inital gtk2 patch
[claws.git] / src / imap.c
index f618742335be02e6ed2056045fe482928c81ce67..19b3d716d8be3f2db90c5c875ab6a5fe84c12f5a 100644 (file)
 #  include <iconv.h>
 #endif
 
+#if USE_OPENSSL
+#  include "ssl.h"
+#endif
+#include "folder.h"
+#include "session.h"
+#include "procmsg.h"
 #include "intl.h"
 #include "imap.h"
 #include "socket.h"
 #include "ssl.h"
 #include "recv.h"
-#include "procmsg.h"
 #include "procheader.h"
-#include "folder.h"
 #include "prefs_account.h"
 #include "codeconv.h"
+#include "md5.h"
+#include "base64.h"
 #include "utils.h"
 #include "inputdialog.h"
 #include "log.h"
 
+typedef struct _IMAPFolder     IMAPFolder;
+typedef struct _IMAPSession    IMAPSession;
+typedef struct _IMAPNameSpace  IMAPNameSpace;
+typedef struct _IMAPFolderItem IMAPFolderItem;
+
+#include "prefs_account.h"
+
+#define IMAP_FOLDER(obj)       ((IMAPFolder *)obj)
+#define IMAP_SESSION(obj)      ((IMAPSession *)obj)
+
+struct _IMAPFolder
+{
+       RemoteFolder rfolder;
+
+       /* list of IMAPNameSpace */
+       GList *ns_personal;
+       GList *ns_others;
+       GList *ns_shared;
+};
+
+struct _IMAPSession
+{
+       Session session;
+
+       gboolean authenticated;
+
+       gchar **capability;
+       gboolean uidplus;
+
+       gchar *mbox;
+       guint cmd_count;
+
+       /* CLAWS */
+       time_t last_access_time;
+       gboolean folder_content_changed;
+       guint exists;
+};
+
+struct _IMAPNameSpace
+{
+       gchar *name;
+       gchar separator;
+};
+
+#define IMAP_SUCCESS   0
+#define IMAP_SOCKET    2
+#define IMAP_AUTHFAIL  3
+#define IMAP_PROTOCOL  4
+#define IMAP_SYNTAX    5
+#define IMAP_IOERR     6
+#define IMAP_ERROR     7
+
+#define IMAPBUFSIZE    8192
+
+typedef enum
+{
+       IMAP_FLAG_SEEN          = 1 << 0,
+       IMAP_FLAG_ANSWERED      = 1 << 1,
+       IMAP_FLAG_FLAGGED       = 1 << 2,
+       IMAP_FLAG_DELETED       = 1 << 3,
+       IMAP_FLAG_DRAFT         = 1 << 4
+} IMAPFlags;
+
+#define IMAP_IS_SEEN(flags)    ((flags & IMAP_FLAG_SEEN) != 0)
+#define IMAP_IS_ANSWERED(flags)        ((flags & IMAP_FLAG_ANSWERED) != 0)
+#define IMAP_IS_FLAGGED(flags) ((flags & IMAP_FLAG_FLAGGED) != 0)
+#define IMAP_IS_DELETED(flags) ((flags & IMAP_FLAG_DELETED) != 0)
+#define IMAP_IS_DRAFT(flags)   ((flags & IMAP_FLAG_DRAFT) != 0)
+
+
 #define IMAP4_PORT     143
 #if USE_OPENSSL
 #define IMAPS_PORT     993
 #endif
 
+#define IMAP_CMD_LIMIT 1000
+
 #define QUOTE_IF_REQUIRED(out, str)                            \
 {                                                              \
        if (*str != '"' && strpbrk(str, " \t(){}%*") != NULL) { \
        }                                                       \
 }
 
+typedef gchar * IMAPSet;
+
 struct _IMAPFolderItem
 {
        FolderItem item;
 
        guint lastuid;
+       guint uid_next;
        GSList *uid_list;
 };
 
-static GList *session_list = NULL;
+static Folder *imap_folder_new(const gchar * name, const gchar * path);
+static void imap_folder_destroy(Folder * folder);
+
+static IMAPSession *imap_session_new(const PrefsAccount * account);
+static void imap_session_authenticate(IMAPSession * session,
+                                     const PrefsAccount * account);
+static void imap_session_destroy(Session * session);
+
+static gchar *imap_fetch_msg(Folder * folder, FolderItem * item, gint uid);
+static gint imap_add_msg(Folder * folder,
+                        FolderItem * dest,
+                        const gchar * file, MsgFlags * flags);
+static gint imap_add_msgs(Folder * folder, FolderItem * dest,
+                         GSList * file_list,
+                         GRelation *relation);
+
+static gint imap_copy_msg(Folder * folder,
+                         FolderItem * dest, MsgInfo * msginfo);
+static gint imap_copy_msgs(Folder *folder, FolderItem *dest, 
+                   MsgInfoList *msglist, GRelation *relation);
+
+static gint imap_remove_msg(Folder * folder, FolderItem * item, gint uid);
+static gint imap_remove_all_msg(Folder * folder, FolderItem * item);
+
+static gboolean imap_is_msg_changed(Folder * folder,
+                                   FolderItem * item, MsgInfo * msginfo);
+
+static gint imap_close(Folder * folder, FolderItem * item);
+
+static void imap_scan_tree(Folder * folder);
+
+static gint imap_create_tree(Folder * folder);
+
+static FolderItem *imap_create_folder(Folder * folder,
+                                     FolderItem * parent,
+                                     const gchar * name);
+static gint imap_rename_folder(Folder * folder,
+                              FolderItem * item, const gchar * name);
+static gint imap_remove_folder(Folder * folder, FolderItem * item);
 
-static gint imap_cmd_count = 0;
 
 static void imap_folder_init           (Folder         *folder,
                                         const gchar    *name,
@@ -91,9 +209,15 @@ static void imap_folder_item_destroy        (Folder         *folder,
 
 static IMAPSession *imap_session_get   (Folder         *folder);
 
+static gint imap_greeting              (IMAPSession    *session);
+static gint imap_auth                  (IMAPSession    *session,
+                                        const gchar    *user,
+                                        const gchar    *pass,
+                                        IMAPAuthType    type);
+
 static gint imap_scan_tree_recursive   (IMAPSession    *session,
                                         FolderItem     *item);
-static GSList *imap_parse_list         (Folder         *folder,
+static GSList *imap_parse_list         (IMAPFolder     *folder,
                                         IMAPSession    *session,
                                         const gchar    *real_path,
                                         gchar          *separator);
@@ -104,21 +228,11 @@ static FolderItem *imap_create_special_folder
                                         SpecialFolderItemType   stype,
                                         const gchar            *name);
 
-static gint imap_do_copy               (Folder         *folder,
+static gint imap_do_copy_msgs          (Folder         *folder,
                                         FolderItem     *dest,
-                                        MsgInfo        *msginfo,
-                                        gboolean        remove_source);
-#if 0
-static gint imap_do_copy_msgs_with_dest        (Folder         *folder,
-                                        FolderItem     *dest, 
-                                        GSList         *msglist,
-                                        gboolean        remove_source);
-#endif
+                                        MsgInfoList    *msglist,
+                                        GRelation      *relation);
 
-static GSList *imap_get_uncached_messages      (IMAPSession    *session,
-                                                FolderItem     *item,
-                                                guint32         first_uid,
-                                                guint32         last_uid);
 static void imap_delete_all_cached_messages    (FolderItem     *item);
 
 #if USE_OPENSSL
@@ -140,15 +254,15 @@ static SockInfo *imap_open_tunnel(const gchar *server,
 #endif
 
 #if USE_OPENSSL
-static SockInfo *imap_init_sock(SockInfo *sock, SSLType         ssl_type);
+static SockInfo *imap_init_sock(SockInfo *sock, SSLType        ssl_type);
 #else
 static SockInfo *imap_init_sock(SockInfo *sock);
 #endif
 
+static gchar *imap_get_flag_str                (IMAPFlags       flags);
 static gint imap_set_message_flags     (IMAPSession    *session,
-                                        guint32         first_uid,
-                                        guint32         last_uid,
-                                        IMAPFlags       flag,
+                                        MsgNumberList  *numlist,
+                                        IMAPFlags       flags,
                                         gboolean        is_set);
 static gint imap_select                        (IMAPSession    *session,
                                         IMAPFolder     *folder,
@@ -186,80 +300,81 @@ static MsgFlags imap_parse_flags  (const gchar    *flag_str);
 static MsgInfo *imap_parse_envelope    (SockInfo       *sock,
                                         FolderItem     *item,
                                         GString        *line_str);
-static gint imap_greeting              (SockInfo       *sock,
-                                        gboolean       *is_preauth);
-static void imap_get_capability                (Session        *session);
+
 static gboolean imap_has_capability    (IMAPSession    *session,
                                         const gchar    *cap);
+static void imap_free_capabilities     (IMAPSession    *session);
 
 /* low-level IMAP4rev1 commands */
-static gint imap_cmd_login     (SockInfo       *sock,
+static gint imap_cmd_authenticate
+                               (IMAPSession    *session,
+                                const gchar    *user,
+                                const gchar    *pass,
+                                IMAPAuthType    type);
+static gint imap_cmd_login     (IMAPSession    *sock,
                                 const gchar    *user,
                                 const gchar    *pass);
-static gint imap_cmd_logout    (SockInfo       *sock);
-static gint imap_cmd_noop      (SockInfo       *sock);
-static gint imap_cmd_starttls  (SockInfo       *sock);
-static gint imap_cmd_namespace (SockInfo       *sock,
+static gint imap_cmd_logout    (IMAPSession    *sock);
+static gint imap_cmd_noop      (IMAPSession    *sock);
+static gint imap_cmd_starttls  (IMAPSession    *sock);
+static gint imap_cmd_namespace (IMAPSession    *sock,
                                 gchar         **ns_str);
-static gint imap_cmd_list      (SockInfo       *sock,
+static gint imap_cmd_list      (IMAPSession    *session,
                                 const gchar    *ref,
                                 const gchar    *mailbox,
                                 GPtrArray      *argbuf);
-static gint imap_cmd_do_select (SockInfo       *sock,
+static gint imap_cmd_do_select (IMAPSession    *sock,
                                 const gchar    *folder,
                                 gboolean        examine,
                                 gint           *exists,
                                 gint           *recent,
                                 gint           *unseen,
                                 guint32        *uid_validity);
-static gint imap_cmd_select    (SockInfo       *sock,
+static gint imap_cmd_select    (IMAPSession    *sock,
                                 const gchar    *folder,
                                 gint           *exists,
                                 gint           *recent,
                                 gint           *unseen,
                                 guint32        *uid_validity);
-static gint imap_cmd_examine   (SockInfo       *sock,
+static gint imap_cmd_examine   (IMAPSession    *sock,
                                 const gchar    *folder,
                                 gint           *exists,
                                 gint           *recent,
                                 gint           *unseen,
                                 guint32        *uid_validity);
-static gint imap_cmd_create    (SockInfo       *sock,
+static gint imap_cmd_create    (IMAPSession    *sock,
                                 const gchar    *folder);
-static gint imap_cmd_rename    (SockInfo       *sock,
+static gint imap_cmd_rename    (IMAPSession    *sock,
                                 const gchar    *oldfolder,
                                 const gchar    *newfolder);
-static gint imap_cmd_delete    (SockInfo       *sock,
+static gint imap_cmd_delete    (IMAPSession    *sock,
                                 const gchar    *folder);
-static gint imap_cmd_envelope  (SockInfo       *sock,
-                                guint32         first_uid,
-                                guint32         last_uid);
-#if 0
-static gint imap_cmd_search    (SockInfo       *sock,
-                                GSList         *numlist);
-#endif
-static gint imap_cmd_fetch     (SockInfo       *sock,
+static gint imap_cmd_envelope  (IMAPSession    *sock,
+                                IMAPSet         set);
+static gint imap_cmd_fetch     (IMAPSession    *sock,
                                 guint32         uid,
                                 const gchar    *filename);
-static gint imap_cmd_append    (SockInfo       *sock,
-                                const gchar    *destfolder,
-                                const gchar    *file);
-static gint imap_cmd_copy      (IMAPSession    *session,
-                                gint32         msgnum,
+static gint imap_cmd_append    (IMAPSession    *session,
                                 const gchar    *destfolder,
-                                gint32         *new_uid);
-static gint imap_cmd_store     (SockInfo       *sock,
-                                guint32         first_uid,
-                                guint32         last_uid,
+                                const gchar    *file,
+                                IMAPFlags       flags,
+                                guint32        *new_uid);
+static gint imap_cmd_copy       (IMAPSession    *session, 
+                                 const gchar    *seq_set, 
+                                 const gchar    *destfolder,
+                                GRelation      *uid_mapping);
+static gint imap_cmd_store     (IMAPSession    *sock,
+                                IMAPSet         set,
                                 gchar          *sub_cmd);
-static gint imap_cmd_expunge   (SockInfo       *sock);
+static gint imap_cmd_expunge   (IMAPSession    *sock);
+static gint imap_cmd_close     (IMAPSession    *session);
 
-static gint imap_cmd_ok                (SockInfo       *sock,
+static gint imap_cmd_ok                (IMAPSession    *session,
                                 GPtrArray      *argbuf);
-static void imap_cmd_gen_send  (SockInfo       *sock,
+static void imap_gen_send      (IMAPSession    *sock,
                                 const gchar    *format, ...);
-static gint imap_cmd_gen_recv  (SockInfo       *sock,
-                                gchar         **buf);
+static gint imap_gen_recv      (IMAPSession    *sock,
+                                gchar         **ret);
 
 /* misc utility functions */
 static gchar *strchr_cpy                       (const gchar    *src,
@@ -277,22 +392,34 @@ static gchar *search_array_str                    (GPtrArray      *array,
 static void imap_path_separator_subst          (gchar          *str,
                                                 gchar           separator);
 
-static gchar *imap_modified_utf7_to_locale     (const gchar    *mutf7_str);
-static gchar *imap_locale_to_modified_utf7     (const gchar    *from);
+static gchar *imap_utf8_to_modified_utf7       (const gchar    *from);
+static gchar *imap_modified_utf7_to_utf8       (const gchar    *mutf7_str);
+
+static GSList *imap_get_seq_set_from_numlist    (MsgNumberList  *msglist);
+static GSList *imap_get_seq_set_from_msglist   (MsgInfoList    *msglist);
+static void imap_seq_set_free                   (GSList         *seq_list);
 
 static gboolean imap_rename_folder_func                (GNode          *node,
                                                 gpointer        data);
-gint imap_get_num_list                         (Folder         *folder,
+static gint imap_get_num_list                  (Folder         *folder,
                                                 FolderItem     *item,
-                                                GSList        **list);
-GSList *imap_get_msginfos                      (Folder         *folder,
+                                                GSList        **list,
+                                                gboolean       *old_uids_valid);
+static GSList *imap_get_msginfos               (Folder         *folder,
                                                 FolderItem     *item,
                                                 GSList         *msgnum_list);
-MsgInfo *imap_get_msginfo                      (Folder         *folder,
+static MsgInfo *imap_get_msginfo               (Folder         *folder,
                                                 FolderItem     *item,
                                                 gint            num);
-gboolean imap_check_msgnum_validity            (Folder         *folder,
+static gboolean imap_scan_required             (Folder         *folder,
                                                 FolderItem     *item);
+static void imap_change_flags                  (Folder         *folder,
+                                                FolderItem     *item,
+                                                MsgInfo        *msginfo,
+                                                MsgPermFlags   newflags);
+static gchar *imap_folder_get_path             (Folder         *folder);
+static gchar *imap_item_get_path               (Folder         *folder,
+                                                FolderItem     *item);
 
 FolderClass imap_class =
 {
@@ -309,32 +436,32 @@ FolderClass imap_class =
        /* FolderItem functions */
        imap_folder_item_new,
        imap_folder_item_destroy,
+       imap_item_get_path,
        imap_create_folder,
        imap_rename_folder,
        imap_remove_folder,
+       imap_close,
        imap_get_num_list,
        NULL,
        NULL,
        NULL,
-       imap_check_msgnum_validity,
+       imap_scan_required,
 
        /* Message functions */
        imap_get_msginfo,
        imap_get_msginfos,
        imap_fetch_msg,
        imap_add_msg,
-       imap_move_msg,
-       NULL,
+       imap_add_msgs,
        imap_copy_msg,
-       NULL,
+       imap_copy_msgs,
        imap_remove_msg,
-       imap_remove_msgs,
        imap_remove_all_msg,
        imap_is_msg_changed,
-       NULL,
+       imap_change_flags,
 };
 
-FolderClass *imap_get_class()
+FolderClass *imap_get_class(void)
 {
        return &imap_class;
 }
@@ -344,7 +471,7 @@ Folder *imap_folder_new(const gchar *name, const gchar *path)
        Folder *folder;
 
        folder = (Folder *)g_new0(IMAPFolder, 1);
-       folder->class = &imap_class;
+       folder->klass = &imap_class;
        imap_folder_init(folder, name, path);
 
        return folder;
@@ -354,7 +481,7 @@ void imap_folder_destroy(Folder *folder)
 {
        gchar *dir;
 
-       dir = folder_get_path(folder);
+       dir = imap_folder_get_path(folder);
        if (is_dir_exist(dir))
                remove_dir_recursive(dir);
        g_free(dir);
@@ -374,6 +501,7 @@ static FolderItem *imap_folder_item_new(Folder *folder)
        
        item = g_new0(IMAPFolderItem, 1);
        item->lastuid = 0;
+       item->uid_next = 0;
        item->uid_list = NULL;
 
        return (FolderItem *)item;
@@ -394,6 +522,7 @@ static gboolean imap_reset_uid_lists_func(GNode *node, gpointer data)
        IMAPFolderItem *item = (IMAPFolderItem *)node->data;
        
        item->lastuid = 0;
+       item->uid_next = 0;
        g_slist_free(item->uid_list);
        item->uid_list = NULL;
        
@@ -409,28 +538,67 @@ static void imap_reset_uid_lists(Folder *folder)
        g_node_traverse(folder->node, G_IN_ORDER, G_TRAVERSE_ALL, -1, imap_reset_uid_lists_func, NULL); 
 }
 
+/* Send CAPABILITY, and examine the server's response to see whether this
+ * connection is pre-authenticated or not and build a list of CAPABILITIES. */
+static gint imap_greeting(IMAPSession *session)
+{
+       gchar *capstr;
+       GPtrArray *argbuf;
+
+       imap_gen_send(session, "CAPABILITY");
+       
+       argbuf = g_ptr_array_new();
+
+       if (imap_cmd_ok(session, argbuf) != IMAP_SUCCESS ||
+           ((capstr = search_array_str(argbuf, "CAPABILITY ")) == NULL)) {
+               ptr_array_free_strings(argbuf);
+               g_ptr_array_free(argbuf, TRUE);
+               return -1;
+       }
+
+       session->authenticated = search_array_str(argbuf, "PREAUTH") != NULL;
+       
+       capstr += strlen("CAPABILITY ");
+
+       IMAP_SESSION(session)->capability = g_strsplit(capstr, " ", 0);
+       
+       ptr_array_free_strings(argbuf);
+       g_ptr_array_free(argbuf, TRUE);
+
+       if (imap_has_capability(session, "UIDPLUS")) 
+               session->uidplus = TRUE; 
+
+       return 0;
+}
+
+static gint imap_auth(IMAPSession *session, const gchar *user, const gchar *pass,
+                     IMAPAuthType type)
+{
+       gint ok;
+
+       if (type == 0 || type == IMAP_AUTH_LOGIN)
+               ok = imap_cmd_login(session, user, pass);
+       else
+               ok = imap_cmd_authenticate(session, user, pass, type);
+
+       if (ok == IMAP_SUCCESS)
+               session->authenticated = TRUE;
+
+       return ok;
+}
+
 static IMAPSession *imap_session_get(Folder *folder)
 {
        RemoteFolder *rfolder = REMOTE_FOLDER(folder);
-       Session *session = NULL;
-       gushort port;
+       IMAPSession *session = NULL;
 
        g_return_val_if_fail(folder != NULL, NULL);
        g_return_val_if_fail(FOLDER_CLASS(folder) == &imap_class, NULL);
        g_return_val_if_fail(folder->account != NULL, NULL);
 
-#if USE_OPENSSL
-       port = folder->account->set_imapport ? folder->account->imapport
-               : folder->account->ssl_imap == SSL_TUNNEL
-               ? IMAPS_PORT : IMAP4_PORT;
-#else
-       port = folder->account->set_imapport ? folder->account->imapport
-               : IMAP4_PORT;
-#endif
-
        /* Make sure we have a session */
        if (rfolder->session != NULL) {
-               session = rfolder->session;
+               session = IMAP_SESSION(rfolder->session);
        } else {
                imap_reset_uid_lists(folder);
                session = imap_session_new(folder->account);
@@ -438,14 +606,18 @@ static IMAPSession *imap_session_get(Folder *folder)
        if(session == NULL)
                return NULL;
 
-       /* Get CAPABILITY */
-       imap_get_capability(session); 
+       if (SESSION(session)->sock->state == CONN_DISCONNECTED) {
+               debug_print("IMAP server disconnected\n");
+               session_destroy(SESSION(session));
+               imap_reset_uid_lists(folder);
+               session = imap_session_new(folder->account);
+       }
 
        /* Make sure session is authenticated */
        if (!IMAP_SESSION(session)->authenticated)
                imap_session_authenticate(IMAP_SESSION(session), folder->account);
        if (!IMAP_SESSION(session)->authenticated) {
-               session_destroy(session);
+               session_destroy(SESSION(session));
                rfolder->session = NULL;
                return NULL;
        }
@@ -464,42 +636,41 @@ static IMAPSession *imap_session_get(Folder *folder)
         * successfully sent. -- mbp */
        if (time(NULL) - session->last_access_time > SESSION_TIMEOUT) {
                /* verify that the session is still alive */
-               if (imap_cmd_noop(session->sock) != IMAP_SUCCESS) {
+               if (imap_cmd_noop(session) != IMAP_SUCCESS) {
                        /* Check if this is the first try to establish a
                           connection, if yes we don't try to reconnect */
                        if (rfolder->session == NULL) {
-                               log_warning(_("Connecting %s:%d failed"),
-                                           folder->account->recv_server, port);
-                               session_destroy(session);
+                               log_warning(_("Connecting %s failed"),
+                                           folder->account->recv_server);
+                               session_destroy(SESSION(session));
                                session = NULL;
                        } else {
-                               log_warning(_("IMAP4 connection to %s:%d has been"
+                               log_warning(_("IMAP4 connection to %s has been"
                                              " disconnected. Reconnecting...\n"),
-                                           folder->account->recv_server, port);
-                               session_destroy(session);
+                                           folder->account->recv_server);
+                               session_destroy(SESSION(session));
                                /* Clear folders session to make imap_session_get create
                                   a new session, because of rfolder->session == NULL
                                   it will not try to reconnect again and so avoid an
                                   endless loop */
                                rfolder->session = NULL;
-                               session = SESSION(imap_session_get(folder));
+                               session = imap_session_get(folder);
                        }
                }
        }
 
-       rfolder->session = session;
+       rfolder->session = SESSION(session);
        if (session) {
                session->last_access_time = time(NULL);
        }
        return IMAP_SESSION(session);
 }
 
-Session *imap_session_new(const PrefsAccount *account)
+IMAPSession *imap_session_new(const PrefsAccount *account)
 {
        IMAPSession *session;
        SockInfo *imap_sock;
        gushort port;
-       gboolean is_preauth;
 
 #ifdef USE_OPENSSL
        /* FIXME: IMAP over SSL only... */ 
@@ -539,33 +710,57 @@ Session *imap_session_new(const PrefsAccount *account)
                        return NULL;
        }
 
-       /* Only need to log in if the connection was not PREAUTH */
-       if (imap_greeting(imap_sock, &is_preauth) != IMAP_SUCCESS) {
-               sock_close(imap_sock);
-               return NULL;
-       }
-       log_message("IMAP connection is %s-authenticated\n",
-                   (is_preauth) ? "pre" : "un");
-
-       session = g_new(IMAPSession, 1);
+       session = g_new0(IMAPSession, 1);
+       session_init(SESSION(session));
        SESSION(session)->type             = SESSION_IMAP;
        SESSION(session)->server           = g_strdup(account->recv_server);
        SESSION(session)->sock             = imap_sock;
-       SESSION(session)->connected        = TRUE;
-       SESSION(session)->phase            = SESSION_READY;
-       SESSION(session)->last_access_time = time(NULL);
-       SESSION(session)->data             = NULL;
 
        SESSION(session)->destroy          = imap_session_destroy;
 
        session->capability = NULL;
 
+       session->authenticated = FALSE;
        session->mbox = NULL;
-       session->authenticated = is_preauth;
+       session->cmd_count = 0;
 
-       session_list = g_list_append(session_list, session);
+       /* Only need to log in if the connection was not PREAUTH */
+       if (imap_greeting(session) != IMAP_SUCCESS) {
+               session_destroy(SESSION(session));
+               return NULL;
+       }
 
-       return SESSION(session);
+#if USE_OPENSSL
+       if (account->ssl_imap == SSL_STARTTLS && 
+           imap_has_capability(session, "STARTTLS")) {
+               gint ok;
+
+               ok = imap_cmd_starttls(session);
+               if (ok != IMAP_SUCCESS) {
+                       log_warning(_("Can't start TLS session.\n"));
+                       session_destroy(SESSION(session));
+                       return NULL;
+               }
+               if (!ssl_init_socket_with_method(SESSION(session)->sock, SSL_METHOD_TLSv1)) {
+                       session_destroy(SESSION(session));
+                       return NULL;
+               }
+
+               imap_free_capabilities(session);
+               session->authenticated = FALSE;
+               session->uidplus = FALSE;
+               session->cmd_count = 1;
+
+               if (imap_greeting(session) != IMAP_SUCCESS) {
+                       session_destroy(SESSION(session));
+                       return NULL;
+               }               
+       }
+#endif
+       log_message("IMAP connection is %s-authenticated\n",
+                   (session->authenticated) ? "pre" : "un");
+
+       return session;
 }
 
 void imap_session_authenticate(IMAPSession *session, const PrefsAccount *account)
@@ -584,8 +779,8 @@ void imap_session_authenticate(IMAPSession *session, const PrefsAccount *account
                g_free(tmp_pass);
        }
 
-       if (imap_cmd_login(SESSION(session)->sock, account->userid, pass) != IMAP_SUCCESS) {
-               imap_cmd_logout(SESSION(session)->sock);
+       if (imap_auth(session, account->userid, pass, account->imap_auth_type) != IMAP_SUCCESS) {
+               imap_cmd_logout(session);
                return;
        }
 
@@ -594,24 +789,10 @@ void imap_session_authenticate(IMAPSession *session, const PrefsAccount *account
 
 void imap_session_destroy(Session *session)
 {
+       imap_free_capabilities(IMAP_SESSION(session));
+       g_free(IMAP_SESSION(session)->mbox);
        sock_close(session->sock);
        session->sock = NULL;
-
-       g_free(IMAP_SESSION(session)->mbox);
-
-       g_strfreev(IMAP_SESSION(session)->capability);
-
-       session_list = g_list_remove(session_list, session);
-}
-
-void imap_session_destroy_all(void)
-{
-       while (session_list != NULL) {
-               IMAPSession *session = (IMAPSession *)session_list->data;
-
-               imap_cmd_logout(SESSION(session)->sock);
-               session_destroy(SESSION(session));
-       }
 }
 
 gchar *imap_fetch_msg(Folder *folder, FolderItem *item, gint uid)
@@ -649,7 +830,7 @@ gchar *imap_fetch_msg(Folder *folder, FolderItem *item, gint uid)
        }
 
        debug_print("getting message %d...\n", uid);
-       ok = imap_cmd_fetch(SESSION(session)->sock, (guint32)uid, filename);
+       ok = imap_cmd_fetch(session, (guint32)uid, filename);
 
        if (ok != IMAP_SUCCESS) {
                g_warning("can't fetch message %d\n", uid);
@@ -660,130 +841,98 @@ gchar *imap_fetch_msg(Folder *folder, FolderItem *item, gint uid)
        return filename;
 }
 
-gint imap_add_msg(Folder *folder, FolderItem *dest, const gchar *file,
-                 gboolean remove_source)
+gint imap_add_msg(Folder *folder, FolderItem *dest, const gchar *file, MsgFlags *flags)
 {
-       gchar *destdir;
-       IMAPSession *session;
-       gint ok;
+       gint ret;
+       GSList file_list;
+       MsgFileInfo fileinfo;
 
-       g_return_val_if_fail(folder != NULL, -1);
-       g_return_val_if_fail(dest != NULL, -1);
        g_return_val_if_fail(file != NULL, -1);
 
-       session = imap_session_get(folder);
-       if (!session) return -1;
-
-       destdir = imap_get_real_path(IMAP_FOLDER(folder), dest->path);
-       ok = imap_cmd_append(SESSION(session)->sock, destdir, file);
-       g_free(destdir);
-
-       if (ok != IMAP_SUCCESS) {
-               g_warning("can't append message %s\n", file);
-               return -1;
-       }
-
-       if (remove_source) {
-               if (unlink(file) < 0)
-                       FILE_OP_ERROR(file, "unlink");
-       }
+       fileinfo.msginfo = NULL;
+       fileinfo.file = (gchar *)file;
+       fileinfo.flags = flags;
+       file_list.data = &fileinfo;
+       file_list.next = NULL;
 
-       return 0;
+       ret = imap_add_msgs(folder, dest, &file_list, NULL);
+       return ret;
 }
 
-static gint imap_do_copy(Folder *folder, FolderItem *dest, MsgInfo *msginfo,
-                        gboolean remove_source)
+gint imap_add_msgs(Folder *folder, FolderItem *dest, GSList *file_list,
+                  GRelation *relation)
 {
        gchar *destdir;
        IMAPSession *session;
-       IMAPFlags iflags = 0;
-       gint messages, recent, unseen;
-       guint32 newuid = 0, uid_validity;
+       guint32 last_uid = 0;
+       GSList *cur;
+       MsgFileInfo *fileinfo;
        gint ok;
-    
+
        g_return_val_if_fail(folder != NULL, -1);
-       g_return_val_if_fail(FOLDER_CLASS(folder) == &imap_class, -1);
        g_return_val_if_fail(dest != NULL, -1);
-       g_return_val_if_fail(msginfo != NULL, -1);
+       g_return_val_if_fail(file_list != NULL, -1);
 
        session = imap_session_get(folder);
        if (!session) return -1;
 
-       if (msginfo->folder == dest) {
-               g_warning("the src folder is identical to the dest.\n");
-               return -1;
-       }
+       destdir = imap_get_real_path(IMAP_FOLDER(folder), dest->path);
 
-       /* if we don't have UIDPLUS we get UID-NEXT and hope that the
-          message really gets this uid */
-       if (!imap_has_capability(session, "UIDPLUS")) {
-               ok = imap_status(session, IMAP_FOLDER(folder), dest->path,
-                                &messages, &recent, &newuid, &uid_validity, &unseen);
-               if (ok != IMAP_SUCCESS) {
-                       g_warning("can't copy message\n");
-                       return -1;
-               }
-       }
+       for (cur = file_list; cur != NULL; cur = cur->next) {
+               IMAPFlags iflags = 0;
+               guint32 new_uid = 0;
 
-       destdir = imap_get_real_path(IMAP_FOLDER(folder), dest->path);
+               fileinfo = (MsgFileInfo *)cur->data;
 
-       /* ensure source folder selected */
-       ok = imap_select(session, IMAP_FOLDER(folder), msginfo->folder->path,
-                        NULL, NULL, NULL, NULL);
-       if (ok != IMAP_SUCCESS)
-               return -1;
-        
-       if (remove_source)
-               debug_print("Moving message %s%c%d to %s ...\n",
-                           msginfo->folder->path, G_DIR_SEPARATOR,
-                           msginfo->msgnum, destdir);
-       else
-               debug_print("Copying message %s%c%d to %s ...\n",
-                           msginfo->folder->path, G_DIR_SEPARATOR,
-                           msginfo->msgnum, destdir);
+               if (fileinfo->flags) {
+                       if (MSG_IS_MARKED(*fileinfo->flags))
+                               iflags |= IMAP_FLAG_FLAGGED;
+                       if (MSG_IS_REPLIED(*fileinfo->flags))
+                               iflags |= IMAP_FLAG_ANSWERED;
+                       if (!MSG_IS_UNREAD(*fileinfo->flags))
+                               iflags |= IMAP_FLAG_SEEN;
+               }
 
-       ok = imap_cmd_copy(session, msginfo->msgnum, destdir, &newuid);
+               if (dest->stype == F_OUTBOX ||
+                   dest->stype == F_QUEUE  ||
+                   dest->stype == F_DRAFT  ||
+                   dest->stype == F_TRASH)
+                       iflags |= IMAP_FLAG_SEEN;
 
-       if (ok == IMAP_SUCCESS && remove_source) {
-               imap_set_message_flags(session, msginfo->msgnum, msginfo->msgnum,
-                                      IMAP_FLAG_DELETED, TRUE);
-               ok = imap_cmd_expunge(SESSION(session)->sock);
-       }
+               ok = imap_cmd_append(session, destdir, fileinfo->file, iflags, 
+                                    &new_uid);
 
-       /* get the dest folder to set the flags */
-       if (newuid) {
-               ok = imap_select(session, IMAP_FOLDER(folder), dest->path,
-                                NULL, NULL, NULL, NULL);
-               if (ok != IMAP_SUCCESS)         /* the folder disappeared? */
-                       return -1;
+               if (ok != IMAP_SUCCESS) {
+                       g_warning("can't append message %s\n", fileinfo->file);
+                       g_free(destdir);
+                       return -1;
+               }
 
-               if (msginfo->flags.perm_flags & MSG_MARKED)  iflags |= IMAP_FLAG_FLAGGED;
-               if (msginfo->flags.perm_flags & MSG_REPLIED) iflags |= IMAP_FLAG_ANSWERED;
-               if (iflags)
-                       if (imap_set_message_flags(session, newuid, newuid, iflags, TRUE)
-                           != IMAP_SUCCESS)
-                               newuid = 0;
+               if (relation != NULL)
+                       g_relation_insert(relation, fileinfo->msginfo != NULL ? 
+                                         (gpointer) fileinfo->msginfo : (gpointer) fileinfo,
+                                         GINT_TO_POINTER(dest->last_num + 1));
+               if (last_uid < new_uid)
+                       last_uid = new_uid;
        }
 
        g_free(destdir);
 
-       if (ok == IMAP_SUCCESS)
-               return newuid;
-       else
-               return -1;
+       return last_uid;
 }
 
-#if 0
-static gint imap_do_copy_msgs_with_dest(Folder *folder, FolderItem *dest, 
-                                       GSList *msglist,
-                                       gboolean remove_source)
+static gint imap_do_copy_msgs(Folder *folder, FolderItem *dest, 
+                             MsgInfoList *msglist, GRelation *relation)
 {
+       FolderItem *src;
        gchar *destdir;
-       GSList *cur;
+       GSList *seq_list, *cur;
        MsgInfo *msginfo;
        IMAPSession *session;
        gint ok = IMAP_SUCCESS;
-
+       GRelation *uid_mapping;
+       gint last_num = 0;
+       
        g_return_val_if_fail(folder != NULL, -1);
        g_return_val_if_fail(dest != NULL, -1);
        g_return_val_if_fail(msglist != NULL, -1);
@@ -791,160 +940,114 @@ static gint imap_do_copy_msgs_with_dest(Folder *folder, FolderItem *dest,
        session = imap_session_get(folder);
        if (!session) return -1;
 
-       destdir = imap_get_real_path(IMAP_FOLDER(folder), dest->path);
+       msginfo = (MsgInfo *)msglist->data;
 
-       for (cur = msglist; cur != NULL; cur = cur->next) {
-               msginfo = (MsgInfo *)cur->data;
+       src = msginfo->folder;
+       if (src == dest) {
+               g_warning("the src folder is identical to the dest.\n");
+               return -1;
+       }
 
-               if (msginfo->folder == dest) {
-                       g_warning("the src folder is identical to the dest.\n");
-                       continue;
-               }
+       ok = imap_select(session, IMAP_FOLDER(folder), msginfo->folder->path,
+                        NULL, NULL, NULL, NULL);
+       if (ok != IMAP_SUCCESS)
+               return ok;
 
-               /* ensure source folder selected */
-               ok = imap_select(session, IMAP_FOLDER(folder), 
-                                msginfo->folder->path, NULL, NULL, NULL, NULL);
-        
-               if (remove_source)
-                       debug_print("Moving message %s%c%d to %s ...\n",
-                                   msginfo->folder->path, G_DIR_SEPARATOR,
-                                   msginfo->msgnum, destdir);
-               else
-                       debug_print("Copying message %s%c%d to %s ...\n",
-                                   msginfo->folder->path, G_DIR_SEPARATOR,
-                                   msginfo->msgnum, destdir);
+       destdir = imap_get_real_path(IMAP_FOLDER(folder), dest->path);
+       seq_list = imap_get_seq_set_from_msglist(msglist);
+       uid_mapping = g_relation_new(2);
+       g_relation_index(uid_mapping, 0, g_direct_hash, g_direct_equal);
+       
+       for (cur = seq_list; cur != NULL; cur = g_slist_next(cur)) {
+               gchar *seq_set = (gchar *)cur->data;
 
-               ok = imap_cmd_copy(session, msginfo, destdir);
+               debug_print("Copying message %s%c[%s] to %s ...\n",
+                           src->path, G_DIR_SEPARATOR,
+                           seq_set, destdir);
 
-               if (ok == IMAP_SUCCESS && remove_source) {
-                       imap_set_message_flags
-                               (session, msginfo->msgnum, msginfo->msgnum,
-                                IMAP_FLAG_DELETED, TRUE);
+               ok = imap_cmd_copy(session, seq_set, destdir, uid_mapping);
+               if (ok != IMAP_SUCCESS) {
+                       g_relation_destroy(uid_mapping);
+                       imap_seq_set_free(seq_list);
+                       return -1;
                }
        }
 
-       if (remove_source)
-               ok = imap_cmd_expunge(SESSION(session)->sock);
+       for (cur = msglist; cur != NULL; cur = g_slist_next(cur)) {
+               MsgInfo *msginfo = (MsgInfo *)cur->data;
+               GTuples *tuples;
+               
+               tuples = g_relation_select(uid_mapping, 
+                                          GINT_TO_POINTER(msginfo->msgnum),
+                                          0);
+               if (tuples->len > 0) {
+                       gint num = GPOINTER_TO_INT(g_tuples_index(tuples, 0, 1));
+                       g_relation_insert(relation, msginfo,
+                                         GPOINTER_TO_INT(num));
+                       if (num > last_num)
+                               last_num = num;
+               } else
+                       g_relation_insert(relation, msginfo,
+                                         GPOINTER_TO_INT(0));
+               g_tuples_destroy(tuples);
+       }
+       
+       imap_seq_set_free(seq_list);
 
        g_free(destdir);
 
        if (ok == IMAP_SUCCESS)
-               return 0;
+               return last_num;
        else
                return -1;
 }
-#endif
 
-gint imap_move_msg(Folder *folder, FolderItem *dest, MsgInfo *msginfo)
+gint imap_copy_msg(Folder *folder, FolderItem *dest, MsgInfo *msginfo)
 {
-       gchar *srcfile;
-       gint ret = 0;
+       GSList msglist;
 
-       g_return_val_if_fail(folder != NULL, -1);
-       g_return_val_if_fail(dest != NULL, -1);
        g_return_val_if_fail(msginfo != NULL, -1);
-       g_return_val_if_fail(msginfo->folder != NULL, -1);
-
-       if (folder == msginfo->folder->folder)
-               return imap_do_copy(folder, dest, msginfo, TRUE);
 
-       srcfile = procmsg_get_message_file(msginfo);
-       if (!srcfile) return -1;
+       msglist.data = msginfo;
+       msglist.next = NULL;
 
-       ret = imap_add_msg(folder, dest, srcfile, FALSE);
-       g_free(srcfile);
-
-       if (ret != -1) {
-               if(folder_item_remove_msg(msginfo->folder, msginfo->msgnum)) {
-                       ret = -1;
-               }
-       }
-               
-       return ret;
+       return imap_copy_msgs(folder, dest, &msglist, NULL);
 }
 
-#if 0
-gint imap_move_msgs_with_dest(Folder *folder, FolderItem *dest, 
-                             GSList *msglist)
+gint imap_copy_msgs(Folder *folder, FolderItem *dest, 
+                   MsgInfoList *msglist, GRelation *relation)
 {
        MsgInfo *msginfo;
-       GSList *cur;
-       gint ret = 0;
+       GSList *file_list;
+       gint ret;
 
        g_return_val_if_fail(folder != NULL, -1);
        g_return_val_if_fail(dest != NULL, -1);
        g_return_val_if_fail(msglist != NULL, -1);
 
        msginfo = (MsgInfo *)msglist->data;
-       if (folder == msginfo->folder->folder)
-               return imap_do_copy_msgs_with_dest(folder, dest, msglist, TRUE);
-
-       for (cur = msglist; cur != NULL; cur = cur->next) {
-               msginfo = (MsgInfo *)cur->data;
-               ret = imap_move_msg(folder, dest, msginfo);
-               if (ret == -1) break;
-       }
-
-       return ret;
-}
-#endif
-
-gint imap_copy_msg(Folder *folder, FolderItem *dest, MsgInfo *msginfo)
-{
-       gchar *srcfile;
-       gint ret = 0;
-
-       g_return_val_if_fail(folder != NULL, -1);
-       g_return_val_if_fail(dest != NULL, -1);
-       g_return_val_if_fail(msginfo != NULL, -1);
        g_return_val_if_fail(msginfo->folder != NULL, -1);
 
        if (folder == msginfo->folder->folder)
-               return imap_do_copy(folder, dest, msginfo, FALSE);
+               return imap_do_copy_msgs(folder, dest, msglist, relation);
 
-       srcfile = procmsg_get_message_file(msginfo);
-       if (!srcfile) return -1;
+       file_list = procmsg_get_message_file_list(msglist);
+       g_return_val_if_fail(file_list != NULL, -1);
 
-       ret = imap_add_msg(folder, dest, srcfile, FALSE);
+       ret = imap_add_msgs(folder, dest, file_list, relation);
 
-       g_free(srcfile);
+       procmsg_message_file_list_free(file_list);
 
        return ret;
 }
 
-#if 0
-gint imap_copy_msgs_with_dest(Folder *folder, FolderItem *dest, 
-                             GSList *msglist)
-{
-       MsgInfo *msginfo;
-       GSList *cur;
-       gint ret = 0;
-
-       g_return_val_if_fail(folder != NULL, -1);
-       g_return_val_if_fail(dest != NULL, -1);
-       g_return_val_if_fail(msglist != NULL, -1);
-
-       msginfo = (MsgInfo *)msglist->data;
-       if (folder == msginfo->folder->folder)
-               return imap_do_copy_msgs_with_dest
-                       (folder, dest, msglist, FALSE);
-
-       for (cur = msglist; cur != NULL; cur = cur->next) {
-               msginfo = (MsgInfo *)cur->data;
-               ret = imap_copy_msg(folder, dest, msginfo);
-               if (ret == -1) break;
-       }
-
-       return ret;
-}
-#endif
-
 gint imap_remove_msg(Folder *folder, FolderItem *item, gint uid)
 {
        gint ok;
        IMAPSession *session;
        gchar *dir;
-
+       MsgNumberList numlist;
+       
        g_return_val_if_fail(folder != NULL, -1);
        g_return_val_if_fail(FOLDER_CLASS(folder) == &imap_class, -1);
        g_return_val_if_fail(item != NULL, -1);
@@ -957,15 +1060,18 @@ gint imap_remove_msg(Folder *folder, FolderItem *item, gint uid)
        if (ok != IMAP_SUCCESS)
                return ok;
 
+       numlist.next = NULL;
+       numlist.data = GINT_TO_POINTER(uid);
+       
        ok = imap_set_message_flags
                (IMAP_SESSION(REMOTE_FOLDER(folder)->session),
-                (guint32)uid, (guint32)uid, IMAP_FLAG_DELETED, TRUE);
+               &numlist, IMAP_FLAG_DELETED, TRUE);
        if (ok != IMAP_SUCCESS) {
                log_warning(_("can't set deleted flags: %d\n"), uid);
                return ok;
        }
 
-       ok = imap_cmd_expunge(SESSION(session)->sock);
+       ok = imap_cmd_expunge(session);
        if (ok != IMAP_SUCCESS) {
                log_warning(_("can't expunge\n"));
                return ok;
@@ -979,63 +1085,8 @@ gint imap_remove_msg(Folder *folder, FolderItem *item, gint uid)
        return IMAP_SUCCESS;
 }
 
-gint imap_remove_msgs(Folder *folder, FolderItem *item, GSList *msglist)
-{
-       gint ok;
-       IMAPSession *session;
-       gchar *dir;
-       MsgInfo *msginfo;
-       GSList *cur;
-       guint32 uid;
-
-       g_return_val_if_fail(folder != NULL, -1);
-       g_return_val_if_fail(FOLDER_CLASS(folder) == &imap_class, -1);
-       g_return_val_if_fail(item != NULL, -1);
-       g_return_val_if_fail(msglist != NULL, -1);
-
-       session = imap_session_get(folder);
-       if (!session) return -1;
-
-       ok = imap_select(session, IMAP_FOLDER(folder), item->path,
-                        NULL, NULL, NULL, NULL);
-       if (ok != IMAP_SUCCESS)
-               return ok;
-
-       for (cur = msglist; cur != NULL; cur = cur->next) {
-               msginfo = (MsgInfo *)cur->data;
-               uid = msginfo->msgnum;
-               ok = imap_set_message_flags
-                       (IMAP_SESSION(REMOTE_FOLDER(folder)->session),
-                        uid, uid, IMAP_FLAG_DELETED, TRUE);
-               if (ok != IMAP_SUCCESS) {
-                       log_warning(_("can't set deleted flags: %d\n"), uid);
-                       return ok;
-               }
-       }
-
-       ok = imap_cmd_expunge(SESSION(session)->sock);
-       if (ok != IMAP_SUCCESS) {
-               log_warning(_("can't expunge\n"));
-               return ok;
-       }
-
-       dir = folder_item_get_path(item);
-       if (is_dir_exist(dir)) {
-               for (cur = msglist; cur != NULL; cur = cur->next) {
-                       msginfo = (MsgInfo *)cur->data;
-                       uid = msginfo->msgnum;
-                       remove_numbered_files(dir, uid, uid);
-               }
-       }
-       g_free(dir);
-       return IMAP_SUCCESS;
-}
-
 gint imap_remove_all_msg(Folder *folder, FolderItem *item)
 {
-        gint exists, recent, unseen;
-        guint32 uid_validity;
        gint ok;
        IMAPSession *session;
        gchar *dir;
@@ -1047,21 +1098,18 @@ gint imap_remove_all_msg(Folder *folder, FolderItem *item)
        if (!session) return -1;
 
        ok = imap_select(session, IMAP_FOLDER(folder), item->path,
-                        &exists, &recent, &unseen, &uid_validity);
+                        NULL, NULL, NULL, NULL);
        if (ok != IMAP_SUCCESS)
                return ok;
-       if (exists == 0)
-               return IMAP_SUCCESS;
 
-       imap_cmd_gen_send(SESSION(session)->sock,
-                         "STORE 1:%d +FLAGS (\\Deleted)", exists);
-       ok = imap_cmd_ok(SESSION(session)->sock, NULL);
+       imap_gen_send(session, "STORE 1:* +FLAGS.SILENT (\\Deleted)");
+       ok = imap_cmd_ok(session, NULL);
        if (ok != IMAP_SUCCESS) {
-               log_warning(_("can't set deleted flags: 1:%d\n"), exists);
+               log_warning(_("can't set deleted flags: 1:*\n"));
                return ok;
        }
 
-       ok = imap_cmd_expunge(SESSION(session)->sock);
+       ok = imap_cmd_expunge(session);
        if (ok != IMAP_SUCCESS) {
                log_warning(_("can't expunge\n"));
                return ok;
@@ -1081,35 +1129,38 @@ gboolean imap_is_msg_changed(Folder *folder, FolderItem *item, MsgInfo *msginfo)
        return FALSE;
 }
 
-gint imap_scan_folder(Folder *folder, FolderItem *item)
+gint imap_close(Folder *folder, FolderItem *item)
 {
-       IMAPSession *session;
-       gint messages, recent, unseen;
-       guint32 uid_next, uid_validity;
        gint ok;
+       IMAPSession *session;
 
        g_return_val_if_fail(folder != NULL, -1);
        g_return_val_if_fail(item != NULL, -1);
+       g_return_val_if_fail(item->path != NULL, -1);
 
        session = imap_session_get(folder);
        if (!session) return -1;
 
-       ok = imap_status(session, IMAP_FOLDER(folder), item->path,
-                        &messages, &recent, &uid_next, &uid_validity, &unseen);
-       if (ok != IMAP_SUCCESS) return -1;
+       if (session->mbox) {
+               if (strcmp(item->path, session->mbox))
+                       return -1;
+
+               ok = imap_cmd_close(session);
+               if (ok != IMAP_SUCCESS)
+                       log_warning(_("can't close folder\n"));
 
-       item->new = unseen > 0 ? recent : 0;
-       item->unread = unseen;
-       item->total = messages;
-       item->last_num = (messages > 0 && uid_next > 0) ? uid_next - 1 : 0;
-       /* item->mtime = uid_validity; */
+               g_free(session->mbox);
+               session->mbox = NULL;
+
+               return ok;
+       }
 
        return 0;
 }
 
 void imap_scan_tree(Folder *folder)
 {
-       FolderItem *item;
+       FolderItem *item = NULL;
        IMAPSession *session;
        gchar *root_folder = NULL;
 
@@ -1122,7 +1173,7 @@ void imap_scan_tree(Folder *folder)
                        folder_tree_destroy(folder);
                        item = folder_item_new(folder, folder->name, NULL);
                        item->folder = folder;
-                       folder->node = g_node_new(item);
+                       folder->node = item->node = g_node_new(item);
                }
                return;
        }
@@ -1133,13 +1184,17 @@ void imap_scan_tree(Folder *folder)
                debug_print("IMAP root directory: %s\n", root_folder);
        }
 
-       item = folder_item_new(folder, folder->name, root_folder);
-       item->folder = folder;
-       item->no_select = TRUE;
-       folder->node = g_node_new(item);
-
-       imap_scan_tree_recursive(session, item);
+       if (folder->node)
+               item = FOLDER_ITEM(folder->node->data);
+       if (!item || ((item->path || root_folder) &&
+                     strcmp2(item->path, root_folder) != 0)) {
+               folder_tree_destroy(folder);
+               item = folder_item_new(folder, folder->name, root_folder);
+               item->folder = folder;
+               folder->node = item->node = g_node_new(item);
+       }
 
+       imap_scan_tree_recursive(session, FOLDER_ITEM(folder->node->data));
        imap_create_missing_folders(folder);
 }
 
@@ -1149,6 +1204,7 @@ static gint imap_scan_tree_recursive(IMAPSession *session, FolderItem *item)
        IMAPFolder *imapfolder;
        FolderItem *new_item;
        GSList *item_list, *cur;
+       GNode *node;
        gchar *real_path;
        gchar *wildcard_path;
        gchar separator;
@@ -1158,13 +1214,13 @@ static gint imap_scan_tree_recursive(IMAPSession *session, FolderItem *item)
        g_return_val_if_fail(item->folder != NULL, -1);
        g_return_val_if_fail(item->no_sub == FALSE, -1);
 
-       folder = FOLDER(item->folder);
+       folder = item->folder;
        imapfolder = IMAP_FOLDER(folder);
 
        separator = imap_get_path_separator(imapfolder, item->path);
 
-       if (item->folder->ui_func)
-               item->folder->ui_func(folder, item, folder->ui_func_data);
+       if (folder->ui_func)
+               folder->ui_func(folder, item, folder->ui_func_data);
 
        if (item->path) {
                wildcard[0] = separator;
@@ -1181,25 +1237,68 @@ static gint imap_scan_tree_recursive(IMAPSession *session, FolderItem *item)
                  {g_free(real_path); return IMAP_ERROR;});
        QUOTE_IF_REQUIRED(wildcard_path, wildcard_path);
 
-       imap_cmd_gen_send(SESSION(session)->sock, "LIST \"\" %s",
-                         wildcard_path);
+       imap_gen_send(session, "LIST \"\" %s",
+                     wildcard_path);
 
        strtailchomp(real_path, separator);
-       item_list = imap_parse_list(folder, session, real_path, NULL);
+       item_list = imap_parse_list(imapfolder, session, real_path, NULL);
        g_free(real_path);
 
+       node = item->node->children;
+       while (node != NULL) {
+               FolderItem *old_item = FOLDER_ITEM(node->data);
+               GNode *next = node->next;
+
+               new_item = NULL;
+               for (cur = item_list; cur != NULL; cur = cur->next) {
+                       FolderItem *cur_item = FOLDER_ITEM(cur->data);
+                       if (!strcmp2(old_item->path, cur_item->path)) {
+                               new_item = cur_item;
+                               break;
+                       }
+               }
+               if (!new_item) {
+                       debug_print("folder '%s' not found. removing...\n",
+                                   old_item->path);
+                       folder_item_remove(old_item);
+               } else {
+                       old_item->no_sub = new_item->no_sub;
+                       old_item->no_select = new_item->no_select;
+                       if (old_item->no_sub == TRUE && node->children) {
+                               debug_print("folder '%s' doesn't have "
+                                           "subfolders. removing...\n",
+                                           old_item->path);
+                               folder_item_remove_children(old_item);
+                       }
+               }
+
+               node = next;
+       }
+
        for (cur = item_list; cur != NULL; cur = cur->next) {
-               new_item = cur->data;
-               if (!strcmp(new_item->path, "INBOX")) {
-                       if (!folder->inbox) {
-                               new_item->stype = F_INBOX;
-                               item->folder->inbox = new_item;
-                       } else {
-                               folder_item_destroy(new_item);
-                               continue;
+               FolderItem *cur_item = FOLDER_ITEM(cur->data);
+               new_item = NULL;
+               for (node = item->node->children; node != NULL;
+                    node = node->next) {
+                       if (!strcmp2(FOLDER_ITEM(node->data)->path,
+                                    cur_item->path)) {
+                               new_item = FOLDER_ITEM(node->data);
+                               folder_item_destroy(cur_item);
+                               cur_item = NULL;
+                               break;
                        }
+               }
+               if (!new_item) {
+                       new_item = cur_item;
+                       debug_print("new folder '%s' found.\n", new_item->path);
+                       folder_item_append(item, new_item);
+               }
+
+               if (!strcmp(new_item->path, "INBOX")) {
+                       new_item->stype = F_INBOX;
+                       folder->inbox = new_item;
                } else if (!item->parent || item->stype == F_INBOX) {
-                       gchar *base;
+                       const gchar *base;
 
                        base = g_basename(new_item->path);
 
@@ -1217,24 +1316,24 @@ static gint imap_scan_tree_recursive(IMAPSession *session, FolderItem *item)
                                folder->trash = new_item;
                        }
                }
-               folder_item_append(item, new_item);
-               if (new_item->no_select == FALSE)
-                       imap_scan_folder(folder, new_item);
+
                if (new_item->no_sub == FALSE)
                        imap_scan_tree_recursive(session, new_item);
        }
 
+       g_slist_free(item_list);
+
        return IMAP_SUCCESS;
 }
 
-static GSList *imap_parse_list(Folder *folder, IMAPSession *session,
+static GSList *imap_parse_list(IMAPFolder *folder, IMAPSession *session,
                               const gchar *real_path, gchar *separator)
 {
        gchar buf[IMAPBUFSIZE];
        gchar flags[256];
        gchar separator_str[16];
        gchar *p;
-       gchar *name;
+       const gchar *name;
        gchar *loc_name, *loc_path;
        GSList *item_list = NULL;
        GString *str;
@@ -1247,7 +1346,7 @@ static GSList *imap_parse_list(Folder *folder, IMAPSession *session,
 
        for (;;) {
                if (sock_gets(SESSION(session)->sock, buf, sizeof(buf)) <= 0) {
-                       log_warning(_("error occured while getting LIST.\n"));
+                       log_warning(_("error occurred while getting LIST.\n"));
                        break;
                }
                strretchomp(buf);
@@ -1292,9 +1391,9 @@ static GSList *imap_parse_list(Folder *folder, IMAPSession *session,
                name = g_basename(buf);
                if (name[0] == '.') continue;
 
-               loc_name = imap_modified_utf7_to_locale(name);
-               loc_path = imap_modified_utf7_to_locale(buf);
-               new_item = folder_item_new(folder, loc_name, loc_path);
+               loc_name = imap_modified_utf7_to_utf8(name);
+               loc_path = imap_modified_utf7_to_utf8(buf);
+               new_item = folder_item_new(FOLDER(folder), loc_name, loc_path);
                if (strcasestr(flags, "\\Noinferiors") != NULL)
                        new_item->no_sub = TRUE;
                if (strcmp(buf, "INBOX") != 0 &&
@@ -1303,7 +1402,7 @@ static GSList *imap_parse_list(Folder *folder, IMAPSession *session,
 
                item_list = g_slist_append(item_list, new_item);
 
-               debug_print("folder %s has been added.\n", loc_path);
+               debug_print("folder '%s' found.\n", loc_path);
                g_free(loc_path);
                g_free(loc_name);
        }
@@ -1380,6 +1479,52 @@ static FolderItem *imap_create_special_folder(Folder *folder,
        return new_item;
 }
 
+static gchar *imap_folder_get_path(Folder *folder)
+{
+       gchar *folder_path;
+
+       g_return_val_if_fail(folder != NULL, NULL);
+        g_return_val_if_fail(folder->account != NULL, NULL);
+
+        folder_path = g_strconcat(get_imap_cache_dir(),
+                                  G_DIR_SEPARATOR_S,
+                                  folder->account->recv_server,
+                                  G_DIR_SEPARATOR_S,
+                                  folder->account->userid,
+                                  NULL);
+
+       return folder_path;
+}
+
+static gchar *imap_item_get_path(Folder *folder, FolderItem *item)
+{
+       gchar *folder_path, *path;
+
+       g_return_val_if_fail(folder != NULL, NULL);
+       g_return_val_if_fail(item != NULL, NULL);
+       folder_path = imap_folder_get_path(folder);
+
+       g_return_val_if_fail(folder_path != NULL, NULL);
+        if (folder_path[0] == G_DIR_SEPARATOR) {
+                if (item->path)
+                        path = g_strconcat(folder_path, G_DIR_SEPARATOR_S,
+                                           item->path, NULL);
+                else
+                        path = g_strdup(folder_path);
+        } else {
+                if (item->path)
+                        path = g_strconcat(get_home_dir(), G_DIR_SEPARATOR_S,
+                                           folder_path, G_DIR_SEPARATOR_S,
+                                           item->path, NULL);
+                else
+                        path = g_strconcat(get_home_dir(), G_DIR_SEPARATOR_S,
+                                           folder_path, NULL);
+        }
+        g_free(folder_path);
+
+       return path;
+}
+
 FolderItem *imap_create_folder(Folder *folder, FolderItem *parent,
                               const gchar *name)
 {
@@ -1416,7 +1561,7 @@ FolderItem *imap_create_folder(Folder *folder, FolderItem *parent,
 
        /* keep trailing directory separator to create a folder that contains
           sub folder */
-       imap_path = imap_locale_to_modified_utf7(dirpath);
+       imap_path = imap_utf8_to_modified_utf7(dirpath);
        strtailchomp(dirpath, '/');
        Xstrdup_a(new_name, name, {g_free(dirpath); return NULL;});
        strtailchomp(new_name, '/');
@@ -1430,7 +1575,7 @@ FolderItem *imap_create_folder(Folder *folder, FolderItem *parent,
                gboolean exist = FALSE;
 
                argbuf = g_ptr_array_new();
-               ok = imap_cmd_list(SESSION(session)->sock, NULL, imap_path,
+               ok = imap_cmd_list(session, NULL, imap_path,
                                   argbuf);
                if (ok != IMAP_SUCCESS) {
                        log_warning(_("can't create mailbox: LIST failed\n"));
@@ -1453,7 +1598,7 @@ FolderItem *imap_create_folder(Folder *folder, FolderItem *parent,
                g_ptr_array_free(argbuf, TRUE);
 
                if (!exist) {
-                       ok = imap_cmd_create(SESSION(session)->sock, imap_path);
+                       ok = imap_cmd_create(session, imap_path);
                        if (ok != IMAP_SUCCESS) {
                                log_warning(_("can't create mailbox\n"));
                                g_free(imap_path);
@@ -1482,7 +1627,6 @@ gint imap_rename_folder(Folder *folder, FolderItem *item, const gchar *name)
        gchar *newpath;
        gchar *real_oldpath;
        gchar *real_newpath;
-       GNode *node;
        gchar *paths[2];
        gchar *old_cache_dir;
        gchar *new_cache_dir;
@@ -1504,7 +1648,7 @@ gint imap_rename_folder(Folder *folder, FolderItem *item, const gchar *name)
 
        g_free(session->mbox);
        session->mbox = NULL;
-       ok = imap_cmd_examine(SESSION(session)->sock, "INBOX",
+       ok = imap_cmd_examine(session, "INBOX",
                              &exists, &recent, &unseen, &uid_validity);
        if (ok != IMAP_SUCCESS) {
                g_free(real_oldpath);
@@ -1519,10 +1663,10 @@ gint imap_rename_folder(Folder *folder, FolderItem *item, const gchar *name)
        } else
                newpath = g_strdup(name);
 
-       real_newpath = imap_locale_to_modified_utf7(newpath);
+       real_newpath = imap_utf8_to_modified_utf7(newpath);
        imap_path_separator_subst(real_newpath, separator);
 
-       ok = imap_cmd_rename(SESSION(session)->sock, real_oldpath, real_newpath);
+       ok = imap_cmd_rename(session, real_oldpath, real_newpath);
        if (ok != IMAP_SUCCESS) {
                log_warning(_("can't rename mailbox: %s to %s\n"),
                            real_oldpath, real_newpath);
@@ -1537,11 +1681,9 @@ gint imap_rename_folder(Folder *folder, FolderItem *item, const gchar *name)
 
        old_cache_dir = folder_item_get_path(item);
 
-       node = g_node_find(item->folder->node, G_PRE_ORDER, G_TRAVERSE_ALL,
-                          item);
        paths[0] = g_strdup(item->path);
        paths[1] = newpath;
-       g_node_traverse(node, G_PRE_ORDER, G_TRAVERSE_ALL, -1,
+       g_node_traverse(item->node, G_PRE_ORDER, G_TRAVERSE_ALL, -1,
                        imap_rename_folder_func, paths);
 
        if (is_dir_exist(old_cache_dir)) {
@@ -1579,14 +1721,14 @@ gint imap_remove_folder(Folder *folder, FolderItem *item)
 
        path = imap_get_real_path(IMAP_FOLDER(folder), item->path);
 
-       ok = imap_cmd_examine(SESSION(session)->sock, "INBOX",
+       ok = imap_cmd_examine(session, "INBOX",
                              &exists, &recent, &unseen, &uid_validity);
        if (ok != IMAP_SUCCESS) {
                g_free(path);
                return -1;
        }
 
-       ok = imap_cmd_delete(SESSION(session)->sock, path);
+       ok = imap_cmd_delete(session, path);
        if (ok != IMAP_SUCCESS) {
                log_warning(_("can't delete mailbox\n"));
                g_free(path);
@@ -1605,72 +1747,79 @@ gint imap_remove_folder(Folder *folder, FolderItem *item)
 
 static GSList *imap_get_uncached_messages(IMAPSession *session,
                                          FolderItem *item,
-                                         guint32 first_uid, guint32 last_uid)
+                                         MsgNumberList *numlist)
 {
        gchar *tmp;
        GSList *newlist = NULL;
        GSList *llast = NULL;
        GString *str;
        MsgInfo *msginfo;
+       GSList *seq_list, *cur;
+       IMAPSet imapset;
 
        g_return_val_if_fail(session != NULL, NULL);
        g_return_val_if_fail(item != NULL, NULL);
        g_return_val_if_fail(item->folder != NULL, NULL);
        g_return_val_if_fail(FOLDER_CLASS(item->folder) == &imap_class, NULL);
-       g_return_val_if_fail(first_uid <= last_uid, NULL);
-
-       if (imap_cmd_envelope(SESSION(session)->sock, first_uid, last_uid)
-           != IMAP_SUCCESS) {
-               log_warning(_("can't get envelope\n"));
-               return NULL;
-       }
 
-       str = g_string_new(NULL);
+       seq_list = imap_get_seq_set_from_numlist(numlist);
+       for (cur = seq_list; cur != NULL; cur = g_slist_next(cur)) {
+               imapset = cur->data;
 
-       for (;;) {
-               if ((tmp = sock_getline(SESSION(session)->sock)) == NULL) {
-                       log_warning(_("error occurred while getting envelope.\n"));
-                       g_string_free(str, TRUE);
-                       return newlist;
-               }
-               strretchomp(tmp);
-               if (tmp[0] != '*' || tmp[1] != ' ') {
-                       log_print("IMAP4< %s\n", tmp);
-                       g_free(tmp);
-                       break;
+               if (imap_cmd_envelope(session, imapset)
+                   != IMAP_SUCCESS) {
+                       log_warning(_("can't get envelope\n"));
+                       continue;
                }
-               if (strstr(tmp, "FETCH") == NULL) {
+
+               str = g_string_new(NULL);
+
+               for (;;) {
+                       if ((tmp = sock_getline(SESSION(session)->sock)) == NULL) {
+                               log_warning(_("error occurred while getting envelope.\n"));
+                               g_string_free(str, TRUE);
+                               break;
+                       }
+                       strretchomp(tmp);
+                       if (tmp[0] != '*' || tmp[1] != ' ') {
+                               log_print("IMAP4< %s\n", tmp);
+                               g_free(tmp);
+                               break;
+                       }
+                       if (strstr(tmp, "FETCH") == NULL) {
+                               log_print("IMAP4< %s\n", tmp);
+                               g_free(tmp);
+                               continue;
+                       }
                        log_print("IMAP4< %s\n", tmp);
+                       g_string_assign(str, tmp);
                        g_free(tmp);
-                       continue;
-               }
-               log_print("IMAP4< %s\n", tmp);
-               g_string_assign(str, tmp);
-               g_free(tmp);
-
-               msginfo = imap_parse_envelope
-                       (SESSION(session)->sock, item, str);
-               if (!msginfo) {
-                       log_warning(_("can't parse envelope: %s\n"), str->str);
-                       continue;
-               }
-               if (item->stype == F_QUEUE) {
-                       MSG_SET_TMP_FLAGS(msginfo->flags, MSG_QUEUED);
-               } else if (item->stype == F_DRAFT) {
-                       MSG_SET_TMP_FLAGS(msginfo->flags, MSG_DRAFT);
-               }
 
-               msginfo->folder = item;
+                       msginfo = imap_parse_envelope
+                               (SESSION(session)->sock, item, str);
+                       if (!msginfo) {
+                               log_warning(_("can't parse envelope: %s\n"), str->str);
+                               continue;
+                       }
+                       if (item->stype == F_QUEUE) {
+                               MSG_SET_TMP_FLAGS(msginfo->flags, MSG_QUEUED);
+                       } else if (item->stype == F_DRAFT) {
+                               MSG_SET_TMP_FLAGS(msginfo->flags, MSG_DRAFT);
+                       }
+
+                       msginfo->folder = item;
 
-               if (!newlist)
-                       llast = newlist = g_slist_append(newlist, msginfo);
-               else {
-                       llast = g_slist_append(llast, msginfo);
-                       llast = llast->next;
+                       if (!newlist)
+                               llast = newlist = g_slist_append(newlist, msginfo);
+                       else {
+                               llast = g_slist_append(llast, msginfo);
+                               llast = llast->next;
+                       }
                }
-       }
 
-       g_string_free(str, TRUE);
+               g_string_free(str, TRUE);
+       }
+       imap_seq_set_free(seq_list);
 
        return newlist;
 }
@@ -1704,10 +1853,11 @@ static SockInfo *imap_open_tunnel(const gchar *server,
 {
        SockInfo *sock;
 
-       if ((sock = sock_connect_cmd(server, tunnelcmd)) == NULL)
+       if ((sock = sock_connect_cmd(server, tunnelcmd)) == NULL) {
                log_warning(_("Can't establish IMAP4 session with: %s\n"),
                            server);
                return NULL;
+       }
 #if USE_OPENSSL
        return imap_init_sock(sock, ssl_type);
 #else
@@ -1738,10 +1888,8 @@ static SockInfo *imap_open(const gchar *server, gushort port)
                sock_close(sock);
                return NULL;
        }
-       return imap_init_sock(sock, ssl_type);
-#else
-       return imap_init_sock(sock);
 #endif
+       return sock;
 }
 
 #if USE_OPENSSL
@@ -1750,29 +1898,6 @@ static SockInfo *imap_init_sock(SockInfo *sock, SSLType ssl_type)
 static SockInfo *imap_init_sock(SockInfo *sock)
 #endif
 {
-       imap_cmd_count = 0;
-#if USE_OPENSSL
-       if (ssl_type == SSL_STARTTLS) {
-               gint ok;
-
-               ok = imap_cmd_starttls(sock);
-               if (ok != IMAP_SUCCESS) {
-                       log_warning(_("Can't start TLS session.\n"));
-                       sock_close(sock);
-                       return NULL;
-               }
-               if (!ssl_init_socket_with_method(sock, SSL_METHOD_TLSv1)) {
-                       sock_close(sock);
-                       return NULL;
-               }
-       }
-#endif
-
-       if (imap_cmd_noop(sock) != IMAP_SUCCESS) {
-               log_warning(_("Can't establish IMAP4 session.\n"));
-               sock_close(sock);
-               return NULL;
-       }
 
        return sock;
 }
@@ -1846,7 +1971,7 @@ static void imap_parse_namespace(IMAPSession *session, IMAPFolder *folder)
                return;
        }
        
-       if (imap_cmd_namespace(SESSION(session)->sock, &ns_str)
+       if (imap_cmd_namespace(session, &ns_str)
            != IMAP_SUCCESS) {
                log_warning(_("can't get namespace\n"));
                return;
@@ -1882,8 +2007,8 @@ static void imap_get_namespace_by_list(IMAPSession *session, IMAPFolder *folder)
            folder->ns_shared   != NULL)
                return;
 
-       imap_cmd_gen_send(SESSION(session)->sock, "LIST \"\" \"\"");
-       item_list = imap_parse_list(NULL, session, "", &separator);
+       imap_gen_send(session, "LIST \"\" \"\"");
+       item_list = imap_parse_list(folder, session, "", &separator);
        for (cur = item_list; cur != NULL; cur = cur->next)
                folder_item_destroy(FOLDER_ITEM(cur->data));
        g_slist_free(item_list);
@@ -1954,7 +2079,7 @@ static gchar *imap_get_real_path(IMAPFolder *folder, const gchar *path)
        g_return_val_if_fail(folder != NULL, NULL);
        g_return_val_if_fail(path != NULL, NULL);
 
-       real_path = imap_locale_to_modified_utf7(path);
+       real_path = imap_utf8_to_modified_utf7(path);
        separator = imap_get_path_separator(folder, path);
        imap_path_separator_subst(real_path, separator);
 
@@ -1999,6 +2124,7 @@ static gchar *imap_parse_atom(SockInfo *sock, gchar *src,
 
                cur_pos = strchr_cpy(cur_pos + 1, '}', buf, sizeof(buf));
                len = atoi(buf);
+               g_return_val_if_fail(len > 0, cur_pos);
 
                g_string_truncate(str, 0);
                cur_pos = str->str;
@@ -2041,6 +2167,7 @@ static gchar *imap_get_header(SockInfo *sock, gchar *cur_pos, gchar **headers,
 
        cur_pos = strchr_cpy(cur_pos + 1, '}', buf, sizeof(buf));
        len = atoi(buf);
+       g_return_val_if_fail(len > 0, cur_pos);
 
        g_string_truncate(str, 0);
        cur_pos = str->str;
@@ -2203,99 +2330,52 @@ static MsgInfo *imap_parse_envelope(SockInfo *sock, FolderItem *item,
        return msginfo;
 }
 
-gint imap_msg_set_perm_flags(MsgInfo *msginfo, MsgPermFlags flags)
+static gchar *imap_get_flag_str(IMAPFlags flags)
 {
-       Folder *folder;
-       IMAPSession *session;
-       IMAPFlags iflags = 0;
-       gint ok = IMAP_SUCCESS;
-
-       g_return_val_if_fail(msginfo != NULL, -1);
-       g_return_val_if_fail(msginfo->folder != NULL, -1);
-       g_return_val_if_fail(msginfo->folder->folder != NULL, -1);
-
-       folder = msginfo->folder->folder;
-       g_return_val_if_fail(FOLDER_CLASS(folder) == &imap_class, -1);
-
-       session = imap_session_get(folder);
-       if (!session) return -1;
-
-       if ((ok = imap_select(session, IMAP_FOLDER(folder), msginfo->folder->path,
-           NULL, NULL, NULL, NULL)) != IMAP_SUCCESS)
-               return ok;
-
-       if (flags & MSG_MARKED)  iflags |= IMAP_FLAG_FLAGGED;
-       if (flags & MSG_REPLIED) iflags |= IMAP_FLAG_ANSWERED;
-       if (iflags) {
-               ok = imap_set_message_flags(session, msginfo->msgnum,
-                                           msginfo->msgnum, iflags, TRUE);
-               if (ok != IMAP_SUCCESS) return ok;
-       }
-
-       if (flags & MSG_UNREAD)
-               ok = imap_set_message_flags(session, msginfo->msgnum,
-                                           msginfo->msgnum, IMAP_FLAG_SEEN,
-                                           FALSE);
-       return ok;
-}
-
-gint imap_msg_unset_perm_flags(MsgInfo *msginfo, MsgPermFlags flags)
-{
-       Folder *folder;
-       IMAPSession *session;
-       IMAPFlags iflags = 0;
-       gint ok = IMAP_SUCCESS;
+       GString *str;
+       gchar *ret;
 
-       g_return_val_if_fail(msginfo != NULL, -1);
-       g_return_val_if_fail(msginfo->folder != NULL, -1);
-       g_return_val_if_fail(msginfo->folder->folder != NULL, -1);
+       str = g_string_new(NULL);
 
-       folder = msginfo->folder->folder;
-       g_return_val_if_fail(FOLDER_CLASS(folder) == &imap_class, -1);
+       if (IMAP_IS_SEEN(flags))        g_string_append(str, "\\Seen ");
+       if (IMAP_IS_ANSWERED(flags))    g_string_append(str, "\\Answered ");
+       if (IMAP_IS_FLAGGED(flags))     g_string_append(str, "\\Flagged ");
+       if (IMAP_IS_DELETED(flags))     g_string_append(str, "\\Deleted ");
+       if (IMAP_IS_DRAFT(flags))       g_string_append(str, "\\Draft");
 
-       session = imap_session_get(folder);
-       if (!session) return -1;
+       if (str->len > 0 && str->str[str->len - 1] == ' ')
+               g_string_truncate(str, str->len - 1);
 
-       if (flags & MSG_MARKED)  iflags |= IMAP_FLAG_FLAGGED;
-       if (flags & MSG_REPLIED) iflags |= IMAP_FLAG_ANSWERED;
-       if (iflags) {
-               ok = imap_set_message_flags(session, msginfo->msgnum,
-                                           msginfo->msgnum, iflags, FALSE);
-               if (ok != IMAP_SUCCESS) return ok;
-       }
+       ret = str->str;
+       g_string_free(str, FALSE);
 
-       if (flags & MSG_UNREAD)
-               ok = imap_set_message_flags(session, msginfo->msgnum,
-                                           msginfo->msgnum, IMAP_FLAG_SEEN,
-                                           TRUE);
-       return ok;
+       return ret;
 }
 
 static gint imap_set_message_flags(IMAPSession *session,
-                                  guint32 first_uid,
-                                  guint32 last_uid,
+                                  MsgNumberList *numlist,
                                   IMAPFlags flags,
                                   gboolean is_set)
 {
-       GString *buf;
+       gchar *cmd;
+       gchar *flag_str;
        gint ok;
+       GSList *seq_list, *cur;
+       IMAPSet imapset;
 
-       buf = g_string_new(is_set ? "+FLAGS (" : "-FLAGS (");
-
-       if (IMAP_IS_SEEN(flags))        g_string_append(buf, "\\Seen ");
-       if (IMAP_IS_ANSWERED(flags))    g_string_append(buf, "\\Answered ");
-       if (IMAP_IS_FLAGGED(flags))     g_string_append(buf, "\\Flagged ");
-       if (IMAP_IS_DELETED(flags))     g_string_append(buf, "\\Deleted ");
-       if (IMAP_IS_DRAFT(flags))       g_string_append(buf, "\\Draft");
-
-       if (buf->str[buf->len - 1] == ' ')
-               g_string_truncate(buf, buf->len - 1);
+       flag_str = imap_get_flag_str(flags);
+       cmd = g_strconcat(is_set ? "+FLAGS.SILENT (" : "-FLAGS.SILENT (",
+                         flag_str, ")", NULL);
+       g_free(flag_str);
 
-       g_string_append_c(buf, ')');
+       seq_list = imap_get_seq_set_from_numlist(numlist);
+       for (cur = seq_list; cur != NULL; cur = g_slist_next(cur)) {
+               imapset = cur->data;
 
-       ok = imap_cmd_store(SESSION(session)->sock, first_uid, last_uid,
-                           buf->str);
-       g_string_free(buf, TRUE);
+               ok = imap_cmd_store(session, imapset, cmd);
+       }
+       imap_seq_set_free(seq_list);
+       g_free(cmd);
 
        return ok;
 }
@@ -2322,12 +2402,14 @@ static gint imap_select(IMAPSession *session, IMAPFolder *folder,
        session->mbox = NULL;
 
        real_path = imap_get_real_path(folder, path);
-       ok = imap_cmd_select(SESSION(session)->sock, real_path,
+       ok = imap_cmd_select(session, real_path,
                             exists, recent, unseen, uid_validity);
        if (ok != IMAP_SUCCESS)
                log_warning(_("can't select folder: %s\n"), real_path);
-       else
+       else {
                session->mbox = g_strdup(path);
+               session->folder_content_changed = FALSE;
+       }
        g_free(real_path);
 
        return ok;
@@ -2349,15 +2431,18 @@ static gint imap_status(IMAPSession *session, IMAPFolder *folder,
 
        *messages = *recent = *uid_next = *uid_validity = *unseen = 0;
 
+       if (path == NULL)
+               return -1;
+
        argbuf = g_ptr_array_new();
 
        real_path = imap_get_real_path(folder, path);
        QUOTE_IF_REQUIRED(real_path_, real_path);
-       imap_cmd_gen_send(SESSION(session)->sock, "STATUS %s "
-                         "(MESSAGES RECENT UIDNEXT UIDVALIDITY UNSEEN)",
-                         real_path_);
+       imap_gen_send(session, "STATUS %s "
+                     "(MESSAGES RECENT UIDNEXT UIDVALIDITY UNSEEN)",
+                     real_path_);
 
-       ok = imap_cmd_ok(SESSION(session)->sock, argbuf);
+       ok = imap_cmd_ok(session, argbuf);
        if (ok != IMAP_SUCCESS) THROW(ok);
 
        str = search_array_str(argbuf, "STATUS");
@@ -2400,103 +2485,109 @@ catch:
 
 #undef THROW
 
-
-/* low-level IMAP4rev1 commands */
-
-static gint imap_cmd_login(SockInfo *sock,
-                          const gchar *user, const gchar *pass)
+static gboolean imap_has_capability(IMAPSession *session, const gchar *cap)
 {
-       gchar *user_, *pass_;
-       gint ok;
-
-       QUOTE_IF_REQUIRED(user_, user);
-       QUOTE_IF_REQUIRED(pass_, pass);
-       imap_cmd_gen_send(sock, "LOGIN %s %s", user_, pass_);
-
-       ok = imap_cmd_ok(sock, NULL);
-       if (ok != IMAP_SUCCESS)
-               log_warning(_("IMAP4 login failed.\n"));
+       gchar **p;
+       
+       for (p = session->capability; *p != NULL; ++p) {
+               if (!g_strcasecmp(*p, cap))
+                       return TRUE;
+       }
 
-       return ok;
+       return FALSE;
 }
 
-static gint imap_cmd_logout(SockInfo *sock)
+void imap_free_capabilities(IMAPSession *session)
 {
-       imap_cmd_gen_send(sock, "LOGOUT");
-       return imap_cmd_ok(sock, NULL);
+       g_strfreev(session->capability);
+       session->capability = NULL;
 }
 
-/* Send a NOOP, and examine the server's response to see whether this
- * connection is pre-authenticated or not. */
-static gint imap_greeting(SockInfo *sock, gboolean *is_preauth)
+/* low-level IMAP4rev1 commands */
+
+static gint imap_cmd_authenticate(IMAPSession *session, const gchar *user,
+                                 const gchar *pass, IMAPAuthType type)
 {
-       GPtrArray *argbuf;
-       gint r;
+       gchar *auth_type;
+       gint ok;
+       gchar *buf = NULL;
+       gchar *challenge;
+       gint challenge_len;
+       gchar hexdigest[33];
+       gchar *response;
+       gchar *response64;
+
+       auth_type = "CRAM-MD5";
+
+       imap_gen_send(session, "AUTHENTICATE %s", auth_type);
+       ok = imap_gen_recv(session, &buf);
+       if (ok != IMAP_SUCCESS || buf[0] != '+' || buf[1] != ' ') {
+               g_free(buf);
+               return IMAP_ERROR;
+       }
 
-       imap_cmd_gen_send(sock, "NOOP");
-       argbuf = g_ptr_array_new(); /* will hold messages sent back */
-       r = imap_cmd_ok(sock, argbuf);
-       *is_preauth = search_array_str(argbuf, "PREAUTH") != NULL;
+       challenge = g_malloc(strlen(buf + 2) + 1);
+       challenge_len = base64_decode(challenge, buf + 2, -1);
+       challenge[challenge_len] = '\0';
+       g_free(buf);
+       log_print("IMAP< [Decoded: %s]\n", challenge);
 
-       ptr_array_free_strings(argbuf);
-       g_ptr_array_free(argbuf, TRUE);
-       
-       return r;
+       md5_hex_hmac(hexdigest, challenge, challenge_len, pass, strlen(pass));
+       g_free(challenge);
+
+       response = g_strdup_printf("%s %s", user, hexdigest);
+       log_print("IMAP> [Encoded: %s]\n", response);
+       response64 = g_malloc((strlen(response) + 3) * 2 + 1);
+       base64_encode(response64, response, strlen(response));
+       g_free(response);
+
+       log_print("IMAP> %s\n", response64);
+       sock_puts(SESSION(session)->sock, response64);
+       ok = imap_cmd_ok(session, NULL);
+       if (ok != IMAP_SUCCESS)
+               log_warning(_("IMAP4 authentication failed.\n"));
+
+       return ok;
 }
 
-static void imap_get_capability(Session *session)
+static gint imap_cmd_login(IMAPSession *session,
+                          const gchar *user, const gchar *pass)
 {
-       gchar *capstr;
-       GPtrArray *argbuf;
-
-       if (IMAP_SESSION(session)->capability != NULL)
-               return;
+       gchar *user_, *pass_;
+       gint ok;
 
-       imap_cmd_gen_send(session->sock, "CAPABILITY");
-       
-       argbuf = g_ptr_array_new();
+       QUOTE_IF_REQUIRED(user_, user);
+       QUOTE_IF_REQUIRED(pass_, pass);
+       imap_gen_send(session, "LOGIN %s %s", user_, pass_);
 
-       if (imap_cmd_ok(session->sock, argbuf) != IMAP_SUCCESS ||
-           ((capstr = search_array_str(argbuf, "CAPABILITY ")) == NULL)) {
-               ptr_array_free_strings(argbuf);
-               g_ptr_array_free(argbuf, TRUE);
-               return;
-       }
-       
-       capstr += strlen("CAPABILITY ");
+       ok = imap_cmd_ok(session, NULL);
+       if (ok != IMAP_SUCCESS)
+               log_warning(_("IMAP4 login failed.\n"));
 
-       IMAP_SESSION(session)->capability = g_strsplit(capstr, " ", 0);
-       
-       ptr_array_free_strings(argbuf);
-       g_ptr_array_free(argbuf, TRUE);
+       return ok;
 }
 
-static gboolean imap_has_capability(IMAPSession *session, const gchar *cap)
+static gint imap_cmd_logout(IMAPSession *session)
 {
-       gchar **p;
-       
-       for (p = session->capability; *p != NULL; ++p)
-               if (g_strcasecmp(*p, cap) == 0)
-                       return TRUE;
-
-       return FALSE;
+       imap_gen_send(session, "LOGOUT");
+       return imap_cmd_ok(session, NULL);
 }
 
-static gint imap_cmd_noop(SockInfo *sock)
+static gint imap_cmd_noop(IMAPSession *session)
 {
-       imap_cmd_gen_send(sock, "NOOP");
-       return imap_cmd_ok(sock, NULL);
+       imap_gen_send(session, "NOOP");
+       return imap_cmd_ok(session, NULL);
 }
 
-static gint imap_cmd_starttls(SockInfo *sock)
+static gint imap_cmd_starttls(IMAPSession *session)
 {
-       imap_cmd_gen_send(sock, "STARTTLS");
-       return imap_cmd_ok(sock, NULL);
+       imap_gen_send(session, "STARTTLS");
+       return imap_cmd_ok(session, NULL);
 }
 
 #define THROW(err) { ok = err; goto catch; }
 
-static gint imap_cmd_namespace(SockInfo *sock, gchar **ns_str)
+static gint imap_cmd_namespace(IMAPSession *session, gchar **ns_str)
 {
        gint ok;
        GPtrArray *argbuf;
@@ -2504,8 +2595,8 @@ static gint imap_cmd_namespace(SockInfo *sock, gchar **ns_str)
 
        argbuf = g_ptr_array_new();
 
-       imap_cmd_gen_send(sock, "NAMESPACE");
-       if ((ok = imap_cmd_ok(sock, argbuf)) != IMAP_SUCCESS) THROW(ok);
+       imap_gen_send(session, "NAMESPACE");
+       if ((ok = imap_cmd_ok(session, argbuf)) != IMAP_SUCCESS) THROW(ok);
 
        str = search_array_str(argbuf, "NAMESPACE");
        if (!str) THROW(IMAP_ERROR);
@@ -2521,7 +2612,7 @@ catch:
 
 #undef THROW
 
-static gint imap_cmd_list(SockInfo *sock, const gchar *ref,
+static gint imap_cmd_list(IMAPSession *session, const gchar *ref,
                          const gchar *mailbox, GPtrArray *argbuf)
 {
        gchar *ref_, *mailbox_;
@@ -2531,14 +2622,14 @@ static gint imap_cmd_list(SockInfo *sock, const gchar *ref,
 
        QUOTE_IF_REQUIRED(ref_, ref);
        QUOTE_IF_REQUIRED(mailbox_, mailbox);
-       imap_cmd_gen_send(sock, "LIST %s %s", ref_, mailbox_);
+       imap_gen_send(session, "LIST %s %s", ref_, mailbox_);
 
-       return imap_cmd_ok(sock, argbuf);
+       return imap_cmd_ok(session, argbuf);
 }
 
 #define THROW goto catch
 
-static gint imap_cmd_do_select(SockInfo *sock, const gchar *folder,
+static gint imap_cmd_do_select(IMAPSession *session, const gchar *folder,
                               gboolean examine,
                               gint *exists, gint *recent, gint *unseen,
                               guint32 *uid_validity)
@@ -2558,9 +2649,9 @@ static gint imap_cmd_do_select(SockInfo *sock, const gchar *folder,
                select_cmd = "SELECT";
 
        QUOTE_IF_REQUIRED(folder_, folder);
-       imap_cmd_gen_send(sock, "%s %s", select_cmd, folder_);
+       imap_gen_send(session, "%s %s", select_cmd, folder_);
 
-       if ((ok = imap_cmd_ok(sock, argbuf)) != IMAP_SUCCESS) THROW;
+       if ((ok = imap_cmd_ok(session, argbuf)) != IMAP_SUCCESS) THROW;
 
        resp_str = search_array_contain_str(argbuf, "EXISTS");
        if (resp_str) {
@@ -2602,57 +2693,57 @@ catch:
        return ok;
 }
 
-static gint imap_cmd_select(SockInfo *sock, const gchar *folder,
+static gint imap_cmd_select(IMAPSession *session, const gchar *folder,
                            gint *exists, gint *recent, gint *unseen,
                            guint32 *uid_validity)
 {
-       return imap_cmd_do_select(sock, folder, FALSE,
+       return imap_cmd_do_select(session, folder, FALSE,
                                  exists, recent, unseen, uid_validity);
 }
 
-static gint imap_cmd_examine(SockInfo *sock, const gchar *folder,
+static gint imap_cmd_examine(IMAPSession *session, const gchar *folder,
                             gint *exists, gint *recent, gint *unseen,
                             guint32 *uid_validity)
 {
-       return imap_cmd_do_select(sock, folder, TRUE,
+       return imap_cmd_do_select(session, folder, TRUE,
                                  exists, recent, unseen, uid_validity);
 }
 
 #undef THROW
 
-static gint imap_cmd_create(SockInfo *sock, const gchar *folder)
+static gint imap_cmd_create(IMAPSession *session, const gchar *folder)
 {
        gchar *folder_;
 
        QUOTE_IF_REQUIRED(folder_, folder);
-       imap_cmd_gen_send(sock, "CREATE %s", folder_);
+       imap_gen_send(session, "CREATE %s", folder_);
 
-       return imap_cmd_ok(sock, NULL);
+       return imap_cmd_ok(session, NULL);
 }
 
-static gint imap_cmd_rename(SockInfo *sock, const gchar *old_folder,
+static gint imap_cmd_rename(IMAPSession *session, const gchar *old_folder,
                            const gchar *new_folder)
 {
        gchar *old_folder_, *new_folder_;
 
        QUOTE_IF_REQUIRED(old_folder_, old_folder);
        QUOTE_IF_REQUIRED(new_folder_, new_folder);
-       imap_cmd_gen_send(sock, "RENAME %s %s", old_folder_, new_folder_);
+       imap_gen_send(session, "RENAME %s %s", old_folder_, new_folder_);
 
-       return imap_cmd_ok(sock, NULL);
+       return imap_cmd_ok(session, NULL);
 }
 
-static gint imap_cmd_delete(SockInfo *sock, const gchar *folder)
+static gint imap_cmd_delete(IMAPSession *session, const gchar *folder)
 {
        gchar *folder_;
 
        QUOTE_IF_REQUIRED(folder_, folder);
-       imap_cmd_gen_send(sock, "DELETE %s", folder_);
+       imap_gen_send(session, "DELETE %s", folder_);
 
-       return imap_cmd_ok(sock, NULL);
+       return imap_cmd_ok(session, NULL);
 }
 
-static gint imap_cmd_search(SockInfo *sock, const gchar *criteria, GSList **list)
+static gint imap_cmd_search(IMAPSession *session, const gchar *criteria, GSList **list)
 {
        gint ok;
        gchar *uidlist;
@@ -2664,9 +2755,9 @@ static gint imap_cmd_search(SockInfo *sock, const gchar *criteria, GSList **list
        *list = NULL;
        
        argbuf = g_ptr_array_new();
-       imap_cmd_gen_send(sock, "UID SEARCH %s", criteria);
+       imap_gen_send(session, "UID SEARCH %s", criteria);
 
-       ok = imap_cmd_ok(sock, argbuf);
+       ok = imap_cmd_ok(session, argbuf);
        if (ok != IMAP_SUCCESS) {
                ptr_array_free_strings(argbuf);
                g_ptr_array_free(argbuf, TRUE);
@@ -2691,53 +2782,54 @@ static gint imap_cmd_search(SockInfo *sock, const gchar *criteria, GSList **list
        return IMAP_SUCCESS;
 }
 
-static gint imap_cmd_fetch(SockInfo *sock, guint32 uid, const gchar *filename)
+static gint imap_cmd_fetch(IMAPSession *session, guint32 uid, const gchar *filename)
 {
        gint ok;
-       gchar *buf;
+       gchar *buf = NULL;
        gchar *cur_pos;
        gchar size_str[32];
        glong size_num;
 
        g_return_val_if_fail(filename != NULL, IMAP_ERROR);
 
-       imap_cmd_gen_send(sock, "UID FETCH %d BODY[]", uid);
+       imap_gen_send(session, "UID FETCH %d BODY.PEEK[]", uid);
 
-       while ((ok = imap_cmd_gen_recv(sock, &buf))
-              == IMAP_SUCCESS) {
+       while ((ok = imap_gen_recv(session, &buf)) == IMAP_SUCCESS) {
                if (buf[0] != '*' || buf[1] != ' ') {
                        g_free(buf);
                        return IMAP_ERROR;
                }
-               if (strstr(buf, "FETCH") != NULL)
-                       break;
+               if (strstr(buf, "FETCH") != NULL) break;
+               g_free(buf);
        }
-       if (ok != IMAP_SUCCESS)
+       if (ok != IMAP_SUCCESS) {
+               g_free(buf);
                return ok;
+       }
 
-       cur_pos = strchr(buf, '{');
-       if (cur_pos == NULL) {
-               g_free(buf);
-               return IMAP_ERROR;
+#define RETURN_ERROR_IF_FAIL(cond)     \
+       if (!(cond)) {                  \
+               g_free(buf);            \
+               return IMAP_ERROR;      \
        }
+
+       cur_pos = strchr(buf, '{');
+       RETURN_ERROR_IF_FAIL(cur_pos != NULL);
        cur_pos = strchr_cpy(cur_pos + 1, '}', size_str, sizeof(size_str));
-       if (cur_pos == NULL) {
-               g_free(buf);
-               return IMAP_ERROR;
-       }
+       RETURN_ERROR_IF_FAIL(cur_pos != NULL);
        size_num = atol(size_str);
+       RETURN_ERROR_IF_FAIL(size_num > 0);
 
-       if (*cur_pos != '\0') {
-               g_free(buf);
-               return IMAP_ERROR;
-       }
+       RETURN_ERROR_IF_FAIL(*cur_pos == '\0');
 
-       if (recv_bytes_write_to_file(sock, size_num, filename) != 0) {
-               g_free(buf);
+#undef RETURN_ERROR_IF_FAIL
+
+       g_free(buf);
+
+       if (recv_bytes_write_to_file(SESSION(session)->sock, size_num, filename) != 0)
                return IMAP_ERROR;
-       }
 
-       if (imap_cmd_gen_recv(sock, &buf) != IMAP_SUCCESS) {
+       if (imap_gen_recv(session, &buf) != IMAP_SUCCESS) {
                g_free(buf);
                return IMAP_ERROR;
        }
@@ -2746,21 +2838,26 @@ static gint imap_cmd_fetch(SockInfo *sock, guint32 uid, const gchar *filename)
                g_free(buf);
                return IMAP_ERROR;
        }
-
        g_free(buf);
-       ok = imap_cmd_ok(sock, NULL);
+
+       ok = imap_cmd_ok(session, NULL);
 
        return ok;
 }
 
-static gint imap_cmd_append(SockInfo *sock, const gchar *destfolder,
-                           const gchar *file)
+static gint imap_cmd_append(IMAPSession *session, const gchar *destfolder,
+                           const gchar *file, IMAPFlags flags, guint32 *new_uid)
 {
        gint ok;
        gint size;
        gchar *destfolder_;
-       gchar buf[BUFFSIZE], *imapbuf;
+       gchar *flag_str;
+       guint32 new_uid_;
+       gchar *ret = NULL;
+       gchar buf[BUFFSIZE];
        FILE *fp;
+       GPtrArray *argbuf;
+       gchar *resp_str;
 
        g_return_val_if_fail(file != NULL, IMAP_ERROR);
 
@@ -2770,24 +2867,26 @@ static gint imap_cmd_append(SockInfo *sock, const gchar *destfolder,
                return -1;
        }
        QUOTE_IF_REQUIRED(destfolder_, destfolder);
-       imap_cmd_gen_send(sock, "APPEND %s (\\Seen) {%d}", destfolder_, size);
+       flag_str = imap_get_flag_str(flags);
+       imap_gen_send(session, "APPEND %s (%s) {%d}", 
+                     destfolder_, flag_str, size);
+       g_free(flag_str);
 
-       ok = imap_cmd_gen_recv(sock, &imapbuf);
-       if (ok != IMAP_SUCCESS || imapbuf[0] != '+' || imapbuf[1] != ' ') {
+       ok = imap_gen_recv(session, &ret);
+       if (ok != IMAP_SUCCESS || ret[0] != '+' || ret[1] != ' ') {
                log_warning(_("can't append %s to %s\n"), file, destfolder_);
-               g_free(imapbuf);
+               g_free(ret);
                fclose(fp);
                return IMAP_ERROR;
        }
-       g_free(imapbuf);
+       g_free(ret);
 
        log_print("IMAP4> %s\n", _("(sending file...)"));
 
        while (fgets(buf, sizeof(buf), fp) != NULL) {
                strretchomp(buf);
-               if (sock_puts(sock, buf) < 0) {
+               if (sock_puts(SESSION(session)->sock, buf) < 0) {
                        fclose(fp);
-                       sock_close(sock);
                        return -1;
                }
        }
@@ -2795,82 +2894,77 @@ static gint imap_cmd_append(SockInfo *sock, const gchar *destfolder,
        if (ferror(fp)) {
                FILE_OP_ERROR(file, "fgets");
                fclose(fp);
-               sock_close(sock);
                return -1;
        }
 
-       sock_puts(sock, "");
+       sock_puts(SESSION(session)->sock, "");
 
        fclose(fp);
-       return imap_cmd_ok(sock, NULL);
-}
-
-#if 0
-static void imap_uidplus_copy(IMAPSession *session, MsgInfo *msginfo,
-                               const gchar *destfolder, const gchar *okmsginfo)
-{
-       unsigned int olduid, newuid;
-       IMAPFlags iflags = 0;
-
-       if (okmsginfo == NULL)
-               return;
-
-       if (sscanf(okmsginfo, "%*u OK [COPYUID %*llu %u %u]", &olduid, &newuid) != 2)
-               return;
 
-       if (olduid != msginfo->msgnum)  /* this should NEVER happen */
-               return;
+       if (new_uid != NULL)
+               *new_uid = 0;
 
-       if (imap_select(session, IMAP_FOLDER(msginfo->folder->folder), destfolder,
-                       NULL, NULL, NULL, NULL) != IMAP_SUCCESS)
-               return;
+       if (new_uid != NULL && session->uidplus) {
+               argbuf = g_ptr_array_new();
 
-       if (msginfo->flags.perm_flags & MSG_MARKED)  iflags |= IMAP_FLAG_FLAGGED;
-       if (msginfo->flags.perm_flags & MSG_REPLIED) iflags |= IMAP_FLAG_ANSWERED;
-       if (iflags)
-               imap_set_message_flags(session, newuid, newuid, iflags, TRUE);
+               ok = imap_cmd_ok(session, argbuf);
+               if (ok != IMAP_SUCCESS)
+                       log_warning(_("can't append message to %s\n"),
+                                   destfolder_);
+               else if (argbuf->len > 0) {
+                       resp_str = g_ptr_array_index(argbuf, argbuf->len - 1);
+                       if (resp_str &&
+                           sscanf(resp_str, "%*u OK [APPENDUID %*u %u]",
+                                  &new_uid_) == 1) {
+                               *new_uid = new_uid_;
+                       }
+               }
 
-       if (msginfo->flags.perm_flags & MSG_UNREAD)
-               imap_set_message_flags(session, newuid, newuid, IMAP_FLAG_SEEN, FALSE);
+               ptr_array_free_strings(argbuf);
+               g_ptr_array_free(argbuf, TRUE);
+       } else
+               ok = imap_cmd_ok(session, NULL);
 
-       imap_select(session, IMAP_FOLDER(msginfo->folder->folder), msginfo->folder->path,
-                   NULL, NULL, NULL, NULL);
+       return ok;
 }
-#endif
 
-static gint imap_cmd_copy(IMAPSession *session,
-    gint32 msgnum, const gchar *destfolder, gint32 *new_uid)
+static gint imap_cmd_copy(IMAPSession *session, const gchar *seq_set,
+                         const gchar *destfolder, GRelation *uid_mapping)
 {
        gint ok;
-       gint32 olduid, newuid;
-       gchar *okmsginfo;
        gchar *destfolder_;
        GPtrArray *reply;
-
-       g_return_val_if_fail(destfolder != NULL, IMAP_ERROR);
+       
        g_return_val_if_fail(session != NULL, IMAP_ERROR);
-       g_return_val_if_fail(new_uid != NULL, IMAP_ERROR);
+       g_return_val_if_fail(seq_set != NULL, IMAP_ERROR);
+       g_return_val_if_fail(destfolder != NULL, IMAP_ERROR);
 
        QUOTE_IF_REQUIRED(destfolder_, destfolder);
-       imap_cmd_gen_send(SESSION(session)->sock, "UID COPY %d %s", msgnum, destfolder_);
+       imap_gen_send(session, "UID COPY %s %s", seq_set, destfolder_);
 
        reply = g_ptr_array_new();
 
-       ok = imap_cmd_ok(SESSION(session)->sock, reply);
+       ok = imap_cmd_ok(session, reply);
        if (ok != IMAP_SUCCESS)
-               log_warning(_("can't copy %d to %s\n"), msgnum, destfolder_);
+               log_warning(_("can't copy %s to %s\n"), seq_set, destfolder_);
+/*
+       TODO: UIDPLUS
+       
+       - split IMAPSets into uids
+       - g_relation_insert(uid_mapping, olduid, newuid);
+
        else if (imap_has_capability(session, "UIDPLUS") && reply->len > 0)
                if ((okmsginfo = g_ptr_array_index(reply, reply->len - 1)) != NULL &&
                    sscanf(okmsginfo, "%*u OK [COPYUID %*u %u %u]", &olduid, &newuid) == 2 &&
                    olduid == msgnum)
                        *new_uid = newuid;
-
+*/
        ptr_array_free_strings(reply);
        g_ptr_array_free(reply, TRUE);
        return ok;
 }
 
-gint imap_cmd_envelope(SockInfo *sock, guint32 first_uid, guint32 last_uid)
+gint imap_cmd_envelope(IMAPSession *session, IMAPSet set)
 {
        static GString *header_fields = NULL;
 
@@ -2899,38 +2993,36 @@ gint imap_cmd_envelope(SockInfo *sock, guint32 first_uid, guint32 last_uid)
                                        namelen, elem->name);
                }
        }
-       
-       imap_cmd_gen_send
-               (sock, "UID FETCH %d:%d (UID FLAGS RFC822.SIZE BODY.PEEK[HEADER.FIELDS (%s)])",
-                first_uid, last_uid,
-                header_fields->str);
+
+       imap_gen_send
+               (session, "UID FETCH %s (UID FLAGS RFC822.SIZE BODY.PEEK[HEADER.FIELDS (%s)])",
+                set, header_fields->str);
 
        return IMAP_SUCCESS;
 }
 
-static gint imap_cmd_store(SockInfo *sock, guint32 first_uid, guint32 last_uid,
+static gint imap_cmd_store(IMAPSession *session, IMAPSet seq_set,
                           gchar *sub_cmd)
 {
        gint ok;
 
-       imap_cmd_gen_send(sock, "UID STORE %d:%d %s",
-                         first_uid, last_uid, sub_cmd);
+       imap_gen_send(session, "UID STORE %s %s", seq_set, sub_cmd);
 
-       if ((ok = imap_cmd_ok(sock, NULL)) != IMAP_SUCCESS) {
-               log_warning(_("error while imap command: STORE %d:%d %s\n"),
-                           first_uid, last_uid, sub_cmd);
+       if ((ok = imap_cmd_ok(session, NULL)) != IMAP_SUCCESS) {
+               log_warning(_("error while imap command: STORE %s %s\n"),
+                           seq_set, sub_cmd);
                return ok;
        }
 
        return IMAP_SUCCESS;
 }
 
-static gint imap_cmd_expunge(SockInfo *sock)
+static gint imap_cmd_expunge(IMAPSession *session)
 {
        gint ok;
 
-       imap_cmd_gen_send(sock, "EXPUNGE");
-       if ((ok = imap_cmd_ok(sock, NULL)) != IMAP_SUCCESS) {
+       imap_gen_send(session, "EXPUNGE");
+       if ((ok = imap_cmd_ok(session, NULL)) != IMAP_SUCCESS) {
                log_warning(_("error while imap command: EXPUNGE\n"));
                return ok;
        }
@@ -2938,70 +3030,98 @@ static gint imap_cmd_expunge(SockInfo *sock)
        return IMAP_SUCCESS;
 }
 
-static gint imap_cmd_ok(SockInfo *sock, GPtrArray *argbuf)
+static gint imap_cmd_close(IMAPSession *session)
 {
        gint ok;
+
+       imap_gen_send(session, "CLOSE");
+       if ((ok = imap_cmd_ok(session, NULL)) != IMAP_SUCCESS)
+               log_warning(_("error while imap command: CLOSE\n"));
+
+       return ok;
+}
+
+static gint imap_cmd_ok(IMAPSession *session, GPtrArray *argbuf)
+{
+       gint ok = IMAP_SUCCESS;
        gchar *buf;
        gint cmd_num;
-       gchar cmd_status[IMAPBUFSIZE];
+       gchar *data;
 
-       while ((ok = imap_cmd_gen_recv(sock, &buf))
+       while ((ok = imap_gen_recv(session, &buf))
               == IMAP_SUCCESS) {
+               // make sure data is long enough for any substring of buf
+               data = alloca(strlen(buf) + 1);
+
+               // untagged line read
                if (buf[0] == '*' && buf[1] == ' ') {
+                       gint num;
                        if (argbuf)
                                g_ptr_array_add(argbuf, g_strdup(buf + 2));
-                       continue;
-               }
 
-               if (sscanf(buf, "%d %s", &cmd_num, cmd_status) < 2)
-                       return IMAP_ERROR;
-               else if (cmd_num == imap_cmd_count &&
-                        !strcmp(cmd_status, "OK")) {
+                       if (sscanf(buf + 2, "%d %s", &num, data) >= 2) {
+                               if (!strcmp(data, "EXISTS")) {
+                                       session->exists = num;
+                                       session->folder_content_changed = TRUE;
+                               }
+
+                               if(!strcmp(data, "EXPUNGE")) {
+                                       session->exists--;
+                                       session->folder_content_changed = TRUE;
+                               }
+                       }
+               // tagged line with correct tag and OK response found
+               } else if ((sscanf(buf, "%d %s", &cmd_num, data) >= 2) &&
+                          (cmd_num == session->cmd_count) &&
+                          !strcmp(data, "OK")) {
                        if (argbuf)
                                g_ptr_array_add(argbuf, g_strdup(buf));
-                       g_free(buf);
-                       return IMAP_SUCCESS;
+                       break;
+               // everything else
                } else {
-                       g_free(buf);
-                       return IMAP_ERROR;
+                       ok = IMAP_ERROR;
+                       break;
                }
+               g_free(buf);
        }
        g_free(buf);
 
        return ok;
 }
 
-static void imap_cmd_gen_send(SockInfo *sock, const gchar *format, ...)
+static void imap_gen_send(IMAPSession *session, const gchar *format, ...)
 {
-       gchar buf[IMAPBUFSIZE];
-       gchar tmp[IMAPBUFSIZE];
+       gchar *buf;
+       gchar *tmp;
        gchar *p;
        va_list args;
 
        va_start(args, format);
-       g_vsnprintf(tmp, sizeof(tmp), format, args);
+       tmp = g_strdup_vprintf(format, args);
        va_end(args);
 
-       imap_cmd_count++;
+       session->cmd_count++;
 
-       g_snprintf(buf, sizeof(buf), "%d %s\r\n", imap_cmd_count, tmp);
+       buf = g_strdup_printf("%d %s\r\n", session->cmd_count, tmp);
        if (!strncasecmp(tmp, "LOGIN ", 6) && (p = strchr(tmp + 6, ' '))) {
                *p = '\0';
-               log_print("IMAP4> %d %s ********\n", imap_cmd_count, tmp);
+               log_print("IMAP4> %d %s ********\n", session->cmd_count, tmp);
        } else
-               log_print("IMAP4> %d %s\n", imap_cmd_count, tmp);
+               log_print("IMAP4> %d %s\n", session->cmd_count, tmp);
 
-       sock_write(sock, buf, strlen(buf));
+       sock_write_all(SESSION(session)->sock, buf, strlen(buf));
+       g_free(tmp);
+       g_free(buf);
 }
 
-static gint imap_cmd_gen_recv(SockInfo *sock, gchar **buf)
+static gint imap_gen_recv(IMAPSession *session, gchar **ret)
 {
-       if ((*buf = sock_getline(sock)) == NULL)
+       if ((*ret = sock_getline(SESSION(session)->sock)) == NULL)
                return IMAP_SOCKET;
 
-       strretchomp(*buf);
+       strretchomp(*ret);
 
-       log_print("IMAP4< %s\n", *buf);
+       log_print("IMAP4< %s\n", *ret);
 
        return IMAP_SUCCESS;
 }
@@ -3098,10 +3218,25 @@ static void imap_path_separator_subst(gchar *str, gchar separator)
        }
 }
 
-static gchar *imap_modified_utf7_to_locale(const gchar *mutf7_str)
+static gchar *imap_modified_utf7_to_utf8(const gchar *mutf7_str)
 {
 #if !HAVE_ICONV
-       return g_strdup(mutf7_str);
+       const gchar *from_p;
+       gchar *to, *to_p;
+
+       to = g_malloc(strlen(mutf7_str) + 1);
+       to_p = to;
+
+       for (from_p = mutf7_str; *from_p != '\0'; from_p++) {
+               if (*from_p == '&' && *(from_p + 1) == '-') {
+                       *to_p++ = '&';
+                       from_p++;
+               } else
+                       *to_p++ = *from_p;
+       }
+       *to_p = '\0';
+
+       return to;
 #else
        static iconv_t cd = (iconv_t)-1;
        static gboolean iconv_ok = TRUE;
@@ -3116,10 +3251,9 @@ static gchar *imap_modified_utf7_to_locale(const gchar *mutf7_str)
        if (!iconv_ok) return g_strdup(mutf7_str);
 
        if (cd == (iconv_t)-1) {
-               cd = iconv_open(conv_get_current_charset_str(), "UTF-7");
+               cd = iconv_open(conv_get_current_charset_str(), CS_UTF_8);
                if (cd == (iconv_t)-1) {
-                       g_warning("iconv cannot convert UTF-7 to %s\n",
-                                 conv_get_current_charset_str());
+                       g_warning(_("iconv cannot convert UTF-7 to UTF-8\n"));
                        iconv_ok = FALSE;
                        return g_strdup(mutf7_str);
                }
@@ -3156,8 +3290,7 @@ static gchar *imap_modified_utf7_to_locale(const gchar *mutf7_str)
 
        if (iconv(cd, (ICONV_CONST gchar **)&norm_utf7_p, &norm_utf7_len,
                  &to_p, &to_len) == -1) {
-               g_warning(_("iconv cannot convert UTF-7 to %s\n"),
-                         conv_get_current_charset_str());
+               g_warning(_("iconv cannot convert UTF-7 to UTF-8\n"));
                g_string_free(norm_utf7, TRUE);
                g_free(to_str);
                return g_strdup(mutf7_str);
@@ -3172,10 +3305,25 @@ static gchar *imap_modified_utf7_to_locale(const gchar *mutf7_str)
 #endif /* !HAVE_ICONV */
 }
 
-static gchar *imap_locale_to_modified_utf7(const gchar *from)
+static gchar *imap_utf8_to_modified_utf7(const gchar *from)
 {
 #if !HAVE_ICONV
-       return g_strdup(from);
+       const gchar *from_p;
+       gchar *to, *to_p;
+
+       to = g_malloc(strlen(from) * 2 + 1);
+       to_p = to;
+
+       for (from_p = from; *from_p != '\0'; from_p++) {
+               if (*from_p == '&') {
+                       *to_p++ = '&';
+                       *to_p++ = '-';
+               } else
+                       *to_p++ = *from_p;
+       }
+       *to_p = '\0';
+
+       return to;
 #else
        static iconv_t cd = (iconv_t)-1;
        static gboolean iconv_ok = TRUE;
@@ -3188,10 +3336,9 @@ static gchar *imap_locale_to_modified_utf7(const gchar *from)
        if (!iconv_ok) return g_strdup(from);
 
        if (cd == (iconv_t)-1) {
-               cd = iconv_open("UTF-7", conv_get_current_charset_str());
+               cd = iconv_open("UTF-7", CS_UTF_8);
                if (cd == (iconv_t)-1) {
-                       g_warning("iconv cannot convert %s to UTF-7\n",
-                                 conv_get_current_charset_str());
+                       g_warning("iconv cannot convert UTF-8 to UTF-7\n");
                        iconv_ok = FALSE;
                        return g_strdup(from);
                }
@@ -3206,25 +3353,39 @@ static gchar *imap_locale_to_modified_utf7(const gchar *from)
 #define IS_PRINT(ch) (isprint(ch) && isascii(ch))
 
        while (from_len > 0) {
-               if (IS_PRINT(*from_tmp)) {
+               if (*from_tmp == '+') {
+                       *norm_utf7_p++ = '+';
+                       *norm_utf7_p++ = '-';
+                       norm_utf7_len -= 2;
+                       from_tmp++;
+                       from_len--;
+               } else if (IS_PRINT(*from_tmp)) {
                        /* printable ascii char */
                        *norm_utf7_p = *from_tmp;
                        norm_utf7_p++;
+                       norm_utf7_len--;
                        from_tmp++;
                        from_len--;
                } else {
-                       size_t mblen;
+                       size_t mb_len = 0, conv_len = 0;
 
                        /* unprintable char: convert to UTF-7 */
-                       for (mblen = 0;
-                            !IS_PRINT(from_tmp[mblen]) && mblen < from_len;
-                            mblen++)
-                               ;
-                       from_len -= mblen;
-                       if (iconv(cd, (ICONV_CONST gchar **)&from_tmp, &mblen,
+                       p = from_tmp;
+                       while (!IS_PRINT(*p) && conv_len < from_len) {
+                               mb_len = mblen(p, MB_LEN_MAX);
+                               if (mb_len <= 0) {
+                                       g_warning("wrong multibyte sequence\n");
+                                       return g_strdup(from);
+                               }
+                               conv_len += mb_len;
+                               p += mb_len;
+                       }
+
+                       from_len -= conv_len;
+                       if (iconv(cd, (ICONV_CONST gchar **)&from_tmp,
+                                 &conv_len,
                                  &norm_utf7_p, &norm_utf7_len) == -1) {
-                               g_warning("iconv cannot convert %s to UTF-7\n",
-                                         conv_get_current_charset_str());
+                               g_warning(_("iconv cannot convert UTF-8 to UTF-7\n"));
                                return g_strdup(from);
                        }
 
@@ -3240,17 +3401,23 @@ static gchar *imap_locale_to_modified_utf7(const gchar *from)
        for (p = norm_utf7; p < norm_utf7_p; p++) {
                /* replace: '&' -> "&-",
                            '+' -> '&',
-                           escaped '/' -> ',' */
+                           "+-" -> '+',
+                           BASE64 '/' -> ',' */
                if (!in_escape && *p == '&') {
                        g_string_append(to_str, "&-");
                } else if (!in_escape && *p == '+') {
-                       g_string_append_c(to_str, '&');
-                       in_escape = TRUE;
+                       if (*(p + 1) == '-') {
+                               g_string_append_c(to_str, '+');
+                               p++;
+                       } else {
+                               g_string_append_c(to_str, '&');
+                               in_escape = TRUE;
+                       }
                } else if (in_escape && *p == '/') {
                        g_string_append_c(to_str, ',');
                } else if (in_escape && *p == '-') {
-                       in_escape = FALSE;
                        g_string_append_c(to_str, '-');
+                       in_escape = FALSE;
                } else {
                        g_string_append_c(to_str, *p);
                }
@@ -3268,6 +3435,84 @@ static gchar *imap_locale_to_modified_utf7(const gchar *from)
 #endif /* !HAVE_ICONV */
 }
 
+static GSList *imap_get_seq_set_from_numlist(MsgNumberList *numlist)
+{
+       GString *str;
+       GSList *sorted_list, *cur;
+       guint first, last, next;
+       gchar *ret_str;
+       GSList *ret_list = NULL;
+
+       if (numlist == NULL)
+               return NULL;
+
+       str = g_string_sized_new(256);
+
+       sorted_list = g_slist_copy(numlist);
+       sorted_list = g_slist_sort(sorted_list, g_int_compare);
+
+       first = GPOINTER_TO_INT(sorted_list->data);
+
+       for (cur = sorted_list; cur != NULL; cur = g_slist_next(cur)) {
+               last = GPOINTER_TO_INT(cur->data);
+               if (cur->next)
+                       next = GPOINTER_TO_INT(cur->next->data);
+               else
+                       next = 0;
+
+               if (last + 1 != next || next == 0) {
+                       if (str->len > 0)
+                               g_string_append_c(str, ',');
+                       if (first == last)
+                               g_string_sprintfa(str, "%u", first);
+                       else
+                               g_string_sprintfa(str, "%u:%u", first, last);
+
+                       first = next;
+
+                       if (str->len > IMAP_CMD_LIMIT) {
+                               ret_str = g_strdup(str->str);
+                               ret_list = g_slist_append(ret_list, ret_str);
+                               g_string_truncate(str, 0);
+                       }
+               }
+       }
+
+       if (str->len > 0) {
+               ret_str = g_strdup(str->str);
+               ret_list = g_slist_append(ret_list, ret_str);
+       }
+
+       g_slist_free(sorted_list);
+       g_string_free(str, TRUE);
+
+       return ret_list;
+}
+
+static GSList *imap_get_seq_set_from_msglist(MsgInfoList *msglist)
+{
+       MsgNumberList *numlist = NULL;
+       MsgInfoList *cur;
+       GSList *seq_list;
+
+       for (cur = msglist; cur != NULL; cur = g_slist_next(cur)) {
+               MsgInfo *msginfo = (MsgInfo *) cur->data;
+
+               numlist = g_slist_append(numlist, GINT_TO_POINTER(msginfo->msgnum));
+       }
+       seq_list = imap_get_seq_set_from_numlist(numlist);
+       g_slist_free(numlist);
+
+       return seq_list;
+}
+
+static void imap_seq_set_free(GSList *seq_list)
+{
+       slist_free_strings(seq_list);
+       g_slist_free(seq_list);
+}
+
+
 static gboolean imap_rename_folder_func(GNode *node, gpointer data)
 {
        FolderItem *item = node->data;
@@ -3297,33 +3542,23 @@ static gboolean imap_rename_folder_func(GNode *node, gpointer data)
        return FALSE;
 }
 
-gint imap_get_num_list(Folder *folder, FolderItem *_item, GSList **msgnum_list)
+static gint get_list_of_uids(Folder *folder, IMAPFolderItem *item, GSList **msgnum_list)
 {
-       IMAPFolderItem *item = (IMAPFolderItem *)_item;
+       gint ok, nummsgs = 0, lastuid_old;
        IMAPSession *session;
-       gint ok, lastuid_old, nummsgs = 0, exists, resent, unseen, uid_val;
        GSList *uidlist, *elem;
-       gchar *dir, *cmd_buf;
-
-       g_return_val_if_fail(folder != NULL, -1);
-       g_return_val_if_fail(item != NULL, -1);
-       g_return_val_if_fail(item->item.path != NULL, -1);
-       g_return_val_if_fail(FOLDER_CLASS(folder) == &imap_class, -1);
-       g_return_val_if_fail(folder->account != NULL, -1);
+       gchar *cmd_buf;
 
        session = imap_session_get(folder);
        g_return_val_if_fail(session != NULL, -1);
 
        ok = imap_select(session, IMAP_FOLDER(folder), item->item.path,
-                        &exists, &resent, &unseen, &uid_val);
+                        NULL, NULL, NULL, NULL);
        if (ok != IMAP_SUCCESS)
                return -1;
 
-       if (exists == 0)
-               return 0;
-
        cmd_buf = g_strdup_printf("UID %d:*", item->lastuid + 1);
-       ok = imap_cmd_search(SESSION(session)->sock, cmd_buf, &uidlist);
+       ok = imap_cmd_search(session, cmd_buf, &uidlist);
        g_free(cmd_buf);
 
        if (ok == IMAP_SOCKET) {
@@ -3339,9 +3574,9 @@ gint imap_get_num_list(Folder *folder, FolderItem *_item, GSList **msgnum_list)
                argbuf = g_ptr_array_new();
 
                cmd_buf = g_strdup_printf("UID FETCH %d:* (UID)", item->lastuid + 1);
-               imap_cmd_gen_send(SESSION(session)->sock, cmd_buf);
+               imap_gen_send(session, cmd_buf);
                g_free(cmd_buf);
-               ok = imap_cmd_ok(SESSION(session)->sock, argbuf);
+               ok = imap_cmd_ok(session, argbuf);
                if (ok != IMAP_SUCCESS) {
                        ptr_array_free_strings(argbuf);
                        g_ptr_array_free(argbuf, TRUE);
@@ -3361,6 +3596,7 @@ gint imap_get_num_list(Folder *folder, FolderItem *_item, GSList **msgnum_list)
 
        lastuid_old = item->lastuid;
        *msgnum_list = g_slist_copy(item->uid_list);
+       nummsgs = g_slist_length(*msgnum_list);
        debug_print("Got %d uids from cache\n", g_slist_length(item->uid_list));
 
        for (elem = uidlist; elem != NULL; elem = g_slist_next(elem)) {
@@ -3378,9 +3614,95 @@ gint imap_get_num_list(Folder *folder, FolderItem *_item, GSList **msgnum_list)
        }
        g_slist_free(uidlist);
 
-       if (g_slist_length(item->uid_list) != exists) {
+       return nummsgs;
+}
+
+gint imap_get_num_list(Folder *folder, FolderItem *_item, GSList **msgnum_list, gboolean *old_uids_valid)
+{
+       IMAPFolderItem *item = (IMAPFolderItem *)_item;
+       IMAPSession *session;
+       gint ok, nummsgs = 0, exists, recent, uid_val, uid_next, unseen;
+       GSList *uidlist;
+       gchar *dir;
+       gboolean selected_folder;
+
+       g_return_val_if_fail(folder != NULL, -1);
+       g_return_val_if_fail(item != NULL, -1);
+       g_return_val_if_fail(item->item.path != NULL, -1);
+       g_return_val_if_fail(FOLDER_CLASS(folder) == &imap_class, -1);
+       g_return_val_if_fail(folder->account != NULL, -1);
+
+       session = imap_session_get(folder);
+       g_return_val_if_fail(session != NULL, -1);
+
+       selected_folder = (session->mbox != NULL) &&
+                         (!strcmp(session->mbox, item->item.path));
+       if (selected_folder) {
+               ok = imap_cmd_noop(session);
+               if (ok != IMAP_SUCCESS)
+                       return -1;
+               exists = session->exists;
+
+               *old_uids_valid = TRUE;
+       } else {
+               ok = imap_status(session, IMAP_FOLDER(folder), item->item.path,
+                                &exists, &recent, &uid_next, &uid_val, &unseen);
+               if (ok != IMAP_SUCCESS)
+                       return -1;
+
+               if(item->item.mtime == uid_val)
+                       *old_uids_valid = TRUE;
+               else {
+                       *old_uids_valid = FALSE;
+
+                       debug_print("Freeing imap uid cache\n");
+                       item->lastuid = 0;
+                       g_slist_free(item->uid_list);
+                       item->uid_list = NULL;
+               
+                       item->item.mtime = uid_val;
+
+                       imap_delete_all_cached_messages((FolderItem *)item);
+               }
+       }
+
+       if (!selected_folder)
+               item->uid_next = uid_next;
+
+       /* If old uid_next matches new uid_next we can be sure no message
+          was added to the folder */
+       if (( selected_folder && !session->folder_content_changed) ||
+           (!selected_folder && uid_next == item->uid_next)) {
+               nummsgs = g_slist_length(item->uid_list);
+
+               /* If number of messages is still the same we
+                   know our caches message numbers are still valid,
+                   otherwise if the number of messages has decrease
+                  we discard our cache to start a new scan to find
+                  out which numbers have been removed */
+               if (exists == nummsgs) {
+                       *msgnum_list = g_slist_copy(item->uid_list);
+                       return nummsgs;
+               } else if (exists < nummsgs) {
+                       debug_print("Freeing imap uid cache");
+                       item->lastuid = 0;
+                       g_slist_free(item->uid_list);
+                       item->uid_list = NULL;
+               }
+       }
+
+       if (exists == 0) {
+               *msgnum_list = NULL;
+               return 0;
+       }
+
+       nummsgs = get_list_of_uids(folder, item, &uidlist);
+
+       if (nummsgs != exists) {
                /* Cache contains more messages then folder, we have cached
-                   an old UID of a message that was removed */
+                   an old UID of a message that was removed and new messages
+                   have been added too, otherwise the uid_next check would
+                  not have failed */
                debug_print("Freeing imap uid cache");
                item->lastuid = 0;
                g_slist_free(item->uid_list);
@@ -3388,9 +3710,11 @@ gint imap_get_num_list(Folder *folder, FolderItem *_item, GSList **msgnum_list)
 
                g_slist_free(*msgnum_list);
 
-               return imap_get_num_list(folder, _item, msgnum_list);
+               nummsgs = get_list_of_uids(folder, item, &uidlist);
        }
 
+       *msgnum_list = uidlist;
+
        dir = folder_item_get_path((FolderItem *)item);
        debug_print("removing old messages from %s\n", dir);
        remove_numbered_files_not_in_list(dir, *msgnum_list);
@@ -3424,16 +3748,11 @@ static MsgInfo *imap_parse_msg(const gchar *file, FolderItem *item)
        return msginfo;
 }
 
-static int compare_uint(gconstpointer a, gconstpointer b)
-{
-       return a-b;
-}
-
 GSList *imap_get_msginfos(Folder *folder, FolderItem *item, GSList *msgnum_list)
 {
        IMAPSession *session;
-       GSList *sorted_list, *elem, *ret = NULL;
-       gint ok, startnum, lastnum;
+       MsgInfoList *ret = NULL;
+       gint ok;
 
        g_return_val_if_fail(folder != NULL, NULL);
        g_return_val_if_fail(item != NULL, NULL);
@@ -3447,22 +3766,25 @@ GSList *imap_get_msginfos(Folder *folder, FolderItem *item, GSList *msgnum_list)
        if (ok != IMAP_SUCCESS)
                return NULL;
 
-       sorted_list = g_slist_sort(g_slist_copy(msgnum_list), compare_uint);
+       if (!(item->stype == F_QUEUE || item->stype == F_DRAFT)) {
+               ret = g_slist_concat(ret,
+                       imap_get_uncached_messages(
+                       session, item, msgnum_list));
+       } else {
+               MsgNumberList *sorted_list, *elem;
+               gint startnum, lastnum;
 
-       startnum = lastnum = GPOINTER_TO_INT(sorted_list->data);
+               sorted_list = g_slist_sort(g_slist_copy(msgnum_list), g_int_compare);
 
-       for (elem = sorted_list;; elem = g_slist_next(elem)) {
-               guint num;
+               startnum = lastnum = GPOINTER_TO_INT(sorted_list->data);
 
-               if (elem)
-                       num = GPOINTER_TO_INT(elem->data);
+               for (elem = sorted_list;; elem = g_slist_next(elem)) {
+                       guint num;
 
-               if (num > lastnum + 1 || elem == NULL) {
-                       if (!(item->stype == F_QUEUE || item->stype == F_DRAFT)) {
-                               ret = g_slist_concat(ret,
-                                       imap_get_uncached_messages(
-                                               session, item, startnum, lastnum));
-                       } else {
+                       if (elem)
+                               num = GPOINTER_TO_INT(elem->data);
+
+                       if (num > lastnum + 1 || elem == NULL) {
                                int i;
                                for (i = startnum; i <= lastnum; ++i) {
                                        gchar *file;
@@ -3477,93 +3799,130 @@ GSList *imap_get_msginfos(Folder *folder, FolderItem *item, GSList *msgnum_list)
                                                g_free(file);
                                        }
                                }
-                       }
 
-                       if (elem == NULL)
-                               break;
+                               if (elem == NULL)
+                                       break;
 
-                       startnum = num;
+                               startnum = num;
+                       }
+                       lastnum = num;
                }
-               lastnum = num;
-       }
 
-       g_slist_free(sorted_list);
+               g_slist_free(sorted_list);
+       }
 
        return ret;
 }
 
 MsgInfo *imap_get_msginfo(Folder *folder, FolderItem *item, gint uid)
 {
-       IMAPSession *session;
        MsgInfo *msginfo = NULL;
-       gint ok;
-
-       g_return_val_if_fail(folder != NULL, NULL);
-       g_return_val_if_fail(item != NULL, NULL);
-
-       session = imap_session_get(folder);
-       g_return_val_if_fail(session != NULL, NULL);
-
-       ok = imap_select(session, IMAP_FOLDER(folder), item->path,
-                        NULL, NULL, NULL, NULL);
-       if (ok != IMAP_SUCCESS)
-               return NULL;
+       MsgInfoList *msginfolist;
+       MsgNumberList numlist;
 
-       if (!(item->stype == F_QUEUE || item->stype == F_DRAFT)) {
-               GSList *list;
+       numlist.next = NULL;
+       numlist.data = GINT_TO_POINTER(uid);
 
-               list = imap_get_uncached_messages(session, item, uid, uid);
-               if (list) {
-                       msginfo = (MsgInfo *)list->data;
-                       list->data = NULL;
-               }
-               procmsg_msg_list_free(list);
-       } else {
-               gchar *file;
-
-               file = imap_fetch_msg(folder, item, uid);
-               if (file != NULL) {
-                       msginfo = imap_parse_msg(file, item);
-                       if (msginfo != NULL)
-                               msginfo->msgnum = uid;
-                       g_free(file);
-               }
+       msginfolist = imap_get_msginfos(folder, item, &numlist);
+       if (msginfolist != NULL) {
+               msginfo = msginfolist->data;
+               g_slist_free(msginfolist);
        }
-       
+
        return msginfo;
 }
 
-gboolean imap_check_msgnum_validity(Folder *folder, FolderItem *_item)
+gboolean imap_scan_required(Folder *folder, FolderItem *_item)
 {
        IMAPSession *session;
        IMAPFolderItem *item = (IMAPFolderItem *)_item;
        gint ok, exists = 0, recent = 0, unseen = 0;
-       guint32 uid_next, uid_validity = 0;
+       guint32 uid_next, uid_val = 0;
+       gboolean selected_folder;
        
        g_return_val_if_fail(folder != NULL, FALSE);
        g_return_val_if_fail(item != NULL, FALSE);
        g_return_val_if_fail(item->item.folder != NULL, FALSE);
        g_return_val_if_fail(FOLDER_CLASS(item->item.folder) == &imap_class, FALSE);
 
+       if (item->item.path == NULL)
+               return FALSE;
+
        session = imap_session_get(folder);
        g_return_val_if_fail(session != NULL, FALSE);
 
-       ok = imap_status(session, IMAP_FOLDER(folder), item->item.path,
-                        &exists, &recent, &uid_next, &uid_validity, &unseen);
-       if (ok != IMAP_SUCCESS)
-               return FALSE;
-
-       if(item->item.mtime == uid_validity)
-               return TRUE;
+       selected_folder = (session->mbox != NULL) &&
+                         (!strcmp(session->mbox, item->item.path));
+       if (selected_folder) {
+               ok = imap_cmd_noop(session);
+               if (ok != IMAP_SUCCESS)
+                       return FALSE;
 
-       debug_print("Freeing imap uid cache");
-       item->lastuid = 0;
-       g_slist_free(item->uid_list);
-       item->uid_list = NULL;
-               
-       item->item.mtime = uid_validity;
+               if (session->folder_content_changed)
+                       return TRUE;
+       } else {
+               ok = imap_status(session, IMAP_FOLDER(folder), item->item.path,
+                                &exists, &recent, &uid_next, &uid_val, &unseen);
+               if (ok != IMAP_SUCCESS)
+                       return FALSE;
 
-       imap_delete_all_cached_messages((FolderItem *)item);
+               if ((uid_next != item->uid_next) || (exists < item->item.total_msgs))
+                       return TRUE;
+       }
 
        return FALSE;
 }
+
+void imap_change_flags(Folder *folder, FolderItem *item, MsgInfo *msginfo, MsgPermFlags newflags)
+{
+       IMAPSession *session;
+       IMAPFlags flags_set = 0, flags_unset = 0;
+       gint ok = IMAP_SUCCESS;
+       MsgNumberList numlist;
+       
+       g_return_if_fail(folder != NULL);
+       g_return_if_fail(folder->klass == &imap_class);
+       g_return_if_fail(item != NULL);
+       g_return_if_fail(item->folder == folder);
+       g_return_if_fail(msginfo != NULL);
+       g_return_if_fail(msginfo->folder == item);
+
+       session = imap_session_get(folder);
+       if (!session) return;
+
+       if ((ok = imap_select(session, IMAP_FOLDER(folder), msginfo->folder->path,
+           NULL, NULL, NULL, NULL)) != IMAP_SUCCESS)
+               return;
+
+       if (!MSG_IS_MARKED(msginfo->flags) &&  (newflags & MSG_MARKED))
+               flags_set |= IMAP_FLAG_FLAGGED;
+       if ( MSG_IS_MARKED(msginfo->flags) && !(newflags & MSG_MARKED))
+               flags_unset |= IMAP_FLAG_FLAGGED;
+
+       if (!MSG_IS_UNREAD(msginfo->flags) &&  (newflags & MSG_UNREAD))
+               flags_unset |= IMAP_FLAG_SEEN;
+       if ( MSG_IS_UNREAD(msginfo->flags) && !(newflags & MSG_UNREAD))
+               flags_set |= IMAP_FLAG_SEEN;
+
+       if (!MSG_IS_REPLIED(msginfo->flags) &&  (newflags & MSG_REPLIED))
+               flags_set |= IMAP_FLAG_ANSWERED;
+       if ( MSG_IS_REPLIED(msginfo->flags) && !(newflags & MSG_REPLIED))
+               flags_set |= IMAP_FLAG_ANSWERED;
+
+       numlist.next = NULL;
+       numlist.data = GINT_TO_POINTER(msginfo->msgnum);
+       
+       if (flags_set) {
+               ok = imap_set_message_flags(session, &numlist, flags_set, TRUE);
+               if (ok != IMAP_SUCCESS) return;
+       }
+
+       if (flags_unset) {
+               ok = imap_set_message_flags(session, &numlist, flags_unset, FALSE);
+               if (ok != IMAP_SUCCESS) return;
+       }
+
+       msginfo->flags.perm_flags = newflags;
+
+       return;
+}