make the progress window more responsive when importing mbox file
[claws.git] / src / mbox.c
index 0e695a6ce8d5ddef91225752c05538c20abe3e26..faa63d55ca727068e33707e3a7d54cd867bedb3f 100644 (file)
@@ -1,6 +1,6 @@
 /*
- * Sylpheed -- a GTK+ based, lightweight, and fast e-mail client
- * Copyright (C) 1999-2007 Hiroyuki Yamamoto and the Claws Mail team
+ * Claws Mail -- a GTK+ based, lightweight, and fast e-mail client
+ * Copyright (C) 1999-2020 the Claws Mail team and Hiroyuki Yamamoto
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  *
  * You should have received a copy of the GNU General Public License
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
- * 
+ *
  */
 
 #ifdef HAVE_CONFIG_H
 #  include "config.h"
+#include "claws-features.h"
 #endif
 
 
-#define _GNU_SOURCE
 #include <stdio.h>
 
+#ifdef USE_PTHREAD
+#include <pthread.h>
+#endif
+
 #include "defs.h"
 #include <glib.h>
 #include <glib/gi18n.h>
 #include "filtering.h"
 #include "alertpanel.h"
 #include "statusbar.h"
+#include "file-utils.h"
 
-#define MSGBUFSIZE     8192
-
-#ifdef HAVE_FGETS_UNLOCKED
-#define SC_FGETS fgets_unlocked
-#define SC_FPUTS fputs_unlocked
-#define SC_FPUTC fputc_unlocked
-#else
-#define SC_FGETS fgets
-#define SC_FPUTS fputs
-#define SC_FPUTC fputc
-#endif
+#define MESSAGEBUFSIZE 8192
 
 #define FPUTS_TO_TMP_ABORT_IF_FAIL(s) \
 { \
        lines++; \
-       if (fputs(s, tmp_fp) == EOF) { \
-               g_warning("can't write to temporary file\n"); \
-               fclose(tmp_fp); \
-               fclose(mbox_fp); \
-               g_unlink(tmp_file); \
+       if (claws_fputs(s, tmp_fp) == EOF) { \
+               g_warning("can't write to temporary file"); \
+               claws_fclose(tmp_fp); \
+               claws_fclose(mbox_fp); \
+               claws_unlink(tmp_file); \
                g_free(tmp_file); \
                return -1; \
        } \
@@ -82,7 +77,7 @@ gint proc_mbox(FolderItem *dest, const gchar *mbox, gboolean apply_filter,
 /* return values: -1 error, >=0 number of msgs added */
 {
        FILE *mbox_fp;
-       gchar buf[MSGBUFSIZE];
+       gchar buf[MESSAGEBUFSIZE];
        gchar *tmp_file;
        gint msgs = 0;
        gint lines;
@@ -91,30 +86,37 @@ gint proc_mbox(FolderItem *dest, const gchar *mbox, gboolean apply_filter,
        GSList *to_filter = NULL, *filtered = NULL, *unfiltered = NULL, *cur, *to_add = NULL;
        gboolean printed = FALSE;
        FolderItem *dropfolder;
+       GStatBuf src_stat;
 
-       g_return_val_if_fail(dest != NULL, -1);
-       g_return_val_if_fail(mbox != NULL, -1);
+       cm_return_val_if_fail(dest != NULL, -1);
+       cm_return_val_if_fail(mbox != NULL, -1);
 
        debug_print("Getting messages from %s into %s...\n", mbox, dest->path);
 
-       if ((mbox_fp = g_fopen(mbox, "rb")) == NULL) {
-               FILE_OP_ERROR(mbox, "fopen");
+       if (g_stat(mbox, &src_stat) < 0) {
+               FILE_OP_ERROR(mbox, "g_stat");
+               alertpanel_error(_("Could not stat mbox file:\n%s\n"), mbox);
+               return -1;
+       }
+
+       if ((mbox_fp = claws_fopen(mbox, "rb")) == NULL) {
+               FILE_OP_ERROR(mbox, "claws_fopen");
                alertpanel_error(_("Could not open mbox file:\n%s\n"), mbox);
                return -1;
        }
 
        /* ignore empty lines on the head */
        do {
-               if (fgets(buf, sizeof(buf), mbox_fp) == NULL) {
-                       g_warning("can't read mbox file.\n");
-                       fclose(mbox_fp);
+               if (claws_fgets(buf, sizeof(buf), mbox_fp) == NULL) {
+                       g_warning("can't read mbox file.");
+                       claws_fclose(mbox_fp);
                        return -1;
                }
        } while (buf[0] == '\n' || buf[0] == '\r');
 
        if (strncmp(buf, "From ", 5) != 0) {
-               g_warning("invalid mbox format: %s\n", mbox);
-               fclose(mbox_fp);
+               g_warning("invalid mbox format: %s", mbox);
+               claws_fclose(mbox_fp);
                return -1;
        }
 
@@ -123,7 +125,7 @@ gint proc_mbox(FolderItem *dest, const gchar *mbox, gboolean apply_filter,
        folder_item_update_freeze();
 
        if (apply_filter)
-               dropfolder = folder_get_default_processing();
+               dropfolder = folder_get_default_processing(account->account_id);
        else
                dropfolder = dest;
        
@@ -132,18 +134,22 @@ gint proc_mbox(FolderItem *dest, const gchar *mbox, gboolean apply_filter,
                gint empty_lines;
                gint msgnum;
                
-               if (msgs > 0 && msgs%500 == 0) {
+               if (msgs%10 == 0) {
+                       long cur_offset_mb = ftell(mbox_fp) / (1024 * 1024);
                        if (printed)
                                statusbar_pop_all();
-                       statusbar_print_all(_("Importing from mbox... (%d mails imported)"), msgs);
+                       statusbar_print_all(
+                                       ngettext("Importing from mbox... (%ld MB imported)",
+                                               "Importing from mbox... (%ld MB imported)", cur_offset_mb), cur_offset_mb);
+                       statusbar_progress_all(cur_offset_mb, src_stat.st_size / (1024*1024), 1);
                        printed=TRUE;
                        GTK_EVENTS_FLUSH();
                }
        
-               if ((tmp_fp = g_fopen(tmp_file, "wb")) == NULL) {
-                       FILE_OP_ERROR(tmp_file, "fopen");
-                       g_warning("can't open temporary file\n");
-                       fclose(mbox_fp);
+               if ((tmp_fp = claws_fopen(tmp_file, "wb")) == NULL) {
+                       FILE_OP_ERROR(tmp_file, "claws_fopen");
+                       g_warning("can't open temporary file");
+                       claws_fclose(mbox_fp);
                        g_free(tmp_file);
                        return -1;
                }
@@ -153,15 +159,11 @@ gint proc_mbox(FolderItem *dest, const gchar *mbox, gboolean apply_filter,
 
                empty_lines = 0;
                lines = 0;
-               more = FALSE;
 
                /* process all lines from mboxrc file */
-               while (fgets(buf, sizeof(buf), mbox_fp) != NULL) {
+               while (claws_fgets(buf, sizeof(buf), mbox_fp) != NULL) {
                        int offset;
 
-                       /* eof not reached, expect more lines */
-                       more = TRUE;
-
                        /* eat empty lines */
                        if (buf[0] == '\n' || buf[0] == '\r') {
                                empty_lines++;
@@ -171,7 +173,7 @@ gint proc_mbox(FolderItem *dest, const gchar *mbox, gboolean apply_filter,
                        /* From separator or quoted From */
                        offset = 0;
                        /* detect leading '>' char(s) */
-                       while ((buf[offset] == '>')) {
+                       while (buf[offset] == '>') {
                                offset++;
                        }
                        if (!strncmp(buf+offset, "From ", 5)) {
@@ -215,31 +217,31 @@ gint proc_mbox(FolderItem *dest, const gchar *mbox, gboolean apply_filter,
                }
 
                /* more emails to expect? */
-               more = !feof(mbox_fp);
+               more = !claws_feof(mbox_fp);
 
                /* warn if email part is empty (it's the minimum check 
                   we can do */
                if (lines == 0) {
-                       g_warning("malformed mbox: %s: message %d is empty\n", mbox, msgs);
-                       fclose(tmp_fp);
-                       fclose(mbox_fp);
-                       g_unlink(tmp_file);
+                       g_warning("malformed mbox: %s: message %d is empty", mbox, msgs);
+                       claws_fclose(tmp_fp);
+                       claws_fclose(mbox_fp);
+                       claws_unlink(tmp_file);
                        return -1;
                }
 
-               if (fclose(tmp_fp) == EOF) {
-                       FILE_OP_ERROR(tmp_file, "fclose");
-                       g_warning("can't write to temporary file\n");
-                       fclose(mbox_fp);
-                       g_unlink(tmp_file);
+               if (claws_safe_fclose(tmp_fp) == EOF) {
+                       FILE_OP_ERROR(tmp_file, "claws_fclose");
+                       g_warning("can't write to temporary file");
+                       claws_fclose(mbox_fp);
+                       claws_unlink(tmp_file);
                        g_free(tmp_file);
                        return -1;
                }
 
                if (apply_filter) {
                        if ((msgnum = folder_item_add_msg(dropfolder, tmp_file, NULL, TRUE)) < 0) {
-                               fclose(mbox_fp);
-                               g_unlink(tmp_file);
+                               claws_fclose(mbox_fp);
+                               claws_unlink(tmp_file);
                                g_free(tmp_file);
                                return -1;
                        }
@@ -262,24 +264,31 @@ gint proc_mbox(FolderItem *dest, const gchar *mbox, gboolean apply_filter,
                msgs++;
        } while (more);
 
-       if (printed)
+       if (printed) {
                statusbar_pop_all();
+               statusbar_progress_all(0, 0, 0);
+       }
 
        if (apply_filter) {
+
+               folder_item_set_batch(dropfolder, FALSE);
                procmsg_msglist_filter(to_filter, account, 
                                &filtered, &unfiltered, TRUE);
+               folder_item_set_batch(dropfolder, TRUE);
 
                filtering_move_and_copy_msgs(to_filter);
                for (cur = filtered; cur; cur = g_slist_next(cur)) {
                        MsgInfo *info = (MsgInfo *)cur->data;
-                       procmsg_msginfo_free(info);
+                       procmsg_msginfo_free(&info);
                }
 
                unfiltered = g_slist_reverse(unfiltered);
-               folder_item_move_msgs(dest, unfiltered);
-               for (cur = unfiltered; cur; cur = g_slist_next(cur)) {
-                       MsgInfo *info = (MsgInfo *)cur->data;
-                       procmsg_msginfo_free(info);
+               if (unfiltered) {
+                       folder_item_move_msgs(dest, unfiltered);
+                       for (cur = unfiltered; cur; cur = g_slist_next(cur)) {
+                               MsgInfo *info = (MsgInfo *)cur->data;
+                               procmsg_msginfo_free(&info);
+                       }
                }
 
                g_slist_free(unfiltered);
@@ -294,7 +303,7 @@ gint proc_mbox(FolderItem *dest, const gchar *mbox, gboolean apply_filter,
        folder_item_update_thaw();
        
        g_free(tmp_file);
-       fclose(mbox_fp);
+       claws_fclose(mbox_fp);
        debug_print("%d messages found.\n", msgs);
 
        return msgs;
@@ -311,17 +320,22 @@ gint lock_mbox(const gchar *base, LockType type)
                FILE *lockfp;
 
                lockfile = g_strdup_printf("%s.%d", base, getpid());
-               if ((lockfp = g_fopen(lockfile, "wb")) == NULL) {
-                       FILE_OP_ERROR(lockfile, "fopen");
-                       g_warning("can't create lock file %s\n", lockfile);
-                       g_warning("use 'flock' instead of 'file' if possible.\n");
+               if ((lockfp = claws_fopen(lockfile, "wb")) == NULL) {
+                       FILE_OP_ERROR(lockfile, "claws_fopen");
+                       g_warning("can't create lock file '%s', use 'flock' instead of 'file' if possible.", lockfile);
                        g_free(lockfile);
                        return -1;
                }
 
-               if (fprintf(lockfp, "%d\n", getpid()) < 0 ||
-                   fclose(lockfp) == EOF) {
-                       FILE_OP_ERROR(lockfile, "fopen||fclose");
+               if (fprintf(lockfp, "%d\n", getpid()) < 0) {
+                       FILE_OP_ERROR(lockfile, "fprintf");
+                       g_free(lockfile);
+                       claws_fclose(lockfp);
+                       return -1;
+               }
+
+               if (claws_safe_fclose(lockfp) == EOF) {
+                       FILE_OP_ERROR(lockfile, "claws_fclose");
                        g_free(lockfile);
                        return -1;
                }
@@ -330,18 +344,18 @@ gint lock_mbox(const gchar *base, LockType type)
                while (link(lockfile, locklink) < 0) {
                        FILE_OP_ERROR(lockfile, "link");
                        if (retry >= 5) {
-                               g_warning("can't create %s\n", lockfile);
-                               g_unlink(lockfile);
+                               g_warning("can't create '%s'", lockfile);
+                               claws_unlink(lockfile);
                                g_free(lockfile);
                                return -1;
                        }
                        if (retry == 0)
                                g_warning("mailbox is owned by another"
-                                           " process, waiting...\n");
+                                         " process, waiting...");
                        retry++;
                        sleep(5);
                }
-               g_unlink(lockfile);
+               claws_unlink(lockfile);
                g_free(lockfile);
        } else if (type == LOCK_FLOCK) {
                gint lockfd;
@@ -355,9 +369,9 @@ gint lock_mbox(const gchar *base, LockType type)
 #endif
 
 #if HAVE_FLOCK
-               if ((lockfd = open(base, O_RDWR)) < 0) {
+               if ((lockfd = g_open(base, O_RDWR, 0)) < 0) {
 #else
-               if ((lockfd = open(base, O_RDWR)) < 0) {
+               if ((lockfd = g_open(base, O_RDWR, 0)) < 0) {
 #endif
                        FILE_OP_ERROR(base, "open");
                        return -1;
@@ -365,7 +379,8 @@ gint lock_mbox(const gchar *base, LockType type)
                
 #if HAVE_FCNTL_H && !defined(G_OS_WIN32)
                if (fcntl(lockfd, F_SETLK, &fl) == -1) {
-                       g_warning("can't fnctl %s (%s)", base, strerror(errno));
+                       g_warning("can't fnctl %s (%s)", base, g_strerror(errno));
+                       close(lockfd);
                        return -1;
                } else {
                        fcntled = TRUE;
@@ -383,14 +398,14 @@ gint lock_mbox(const gchar *base, LockType type)
                {
 #endif
 #endif /* HAVE_FLOCK */
-                       g_warning("can't lock %s\n", base);
+                       g_warning("can't lock %s", base);
                        if (close(lockfd) < 0)
                                perror("close");
                        return -1;
                }
                retval = lockfd;
        } else {
-               g_warning("invalid lock type\n");
+               g_warning("invalid lock type");
                return -1;
        }
 
@@ -406,7 +421,7 @@ gint unlock_mbox(const gchar *base, gint fd, LockType type)
                gchar *lockfile;
 
                lockfile = g_strconcat(base, ".lock", NULL);
-               if (g_unlink(lockfile) < 0) {
+               if (claws_unlink(lockfile) < 0) {
                        FILE_OP_ERROR(lockfile, "unlink");
                        g_free(lockfile);
                        return -1;
@@ -415,8 +430,8 @@ gint unlock_mbox(const gchar *base, gint fd, LockType type)
 
                return 0;
        } else if (type == LOCK_FLOCK) {
-               gboolean fcntled = FALSE;
 #if HAVE_FCNTL_H && !defined(G_OS_WIN32)
+               gboolean fcntled = FALSE;
                struct flock fl;
                fl.l_type = F_UNLCK;
                fl.l_whence = SEEK_SET;
@@ -440,7 +455,7 @@ gint unlock_mbox(const gchar *base, gint fd, LockType type)
                {
 #endif
 #endif /* HAVE_FLOCK */
-                       g_warning("can't unlock %s\n", base);
+                       g_warning("can't unlock %s", base);
                        if (close(fd) < 0)
                                perror("close");
                        return -1;
@@ -454,7 +469,7 @@ gint unlock_mbox(const gchar *base, gint fd, LockType type)
                return 0;
        }
 
-       g_warning("invalid lock type\n");
+       g_warning("invalid lock type");
        return -1;
 }
 
@@ -470,42 +485,38 @@ gint copy_mbox(gint srcfd, const gchar *dest)
                return -1;
        }
 
-       if ((dest_fp = g_fopen(dest, "wb")) == NULL) {
-               FILE_OP_ERROR(dest, "fopen");
+       if ((dest_fp = claws_fopen(dest, "wb")) == NULL) {
+               FILE_OP_ERROR(dest, "claws_fopen");
                return -1;
        }
 
        if (change_file_mode_rw(dest_fp, dest) < 0) {
                FILE_OP_ERROR(dest, "chmod");
-               g_warning("can't change file mode\n");
+               g_warning("can't change file mode");
        }
 
        while ((n_read = read(srcfd, buf, sizeof(buf))) > 0) {
-               if (n_read == -1 && errno != 0) {
-                       save_errno = errno;
-                       break;
-               }
-               if (fwrite(buf, 1, n_read, dest_fp) < n_read) {
-                       g_warning("writing to %s failed.\n", dest);
-                       fclose(dest_fp);
-                       g_unlink(dest);
+               if (claws_fwrite(buf, 1, n_read, dest_fp) < n_read) {
+                       g_warning("writing to %s failed.", dest);
+                       claws_fclose(dest_fp);
+                       claws_unlink(dest);
                        return -1;
                }
        }
 
        if (save_errno != 0) {
-               g_warning("error %d reading mbox: %s\n", save_errno,
-                               strerror(save_errno));
+               g_warning("error %d reading mbox: %s", save_errno,
+                               g_strerror(save_errno));
                err = TRUE;
        }
 
-       if (fclose(dest_fp) == EOF) {
-               FILE_OP_ERROR(dest, "fclose");
+       if (claws_safe_fclose(dest_fp) == EOF) {
+               FILE_OP_ERROR(dest, "claws_fclose");
                err = TRUE;
        }
 
        if (err) {
-               g_unlink(dest);
+               claws_unlink(dest);
                return -1;
        }
 
@@ -516,12 +527,12 @@ void empty_mbox(const gchar *mbox)
 {
        FILE *fp;
 
-       if ((fp = g_fopen(mbox, "wb")) == NULL) {
-               FILE_OP_ERROR(mbox, "fopen");
-               g_warning("can't truncate mailbox to zero.\n");
+       if ((fp = claws_fopen(mbox, "wb")) == NULL) {
+               FILE_OP_ERROR(mbox, "claws_fopen");
+               g_warning("can't truncate mailbox to zero.");
                return;
        }
-       fclose(fp);
+       claws_safe_fclose(fp);
 }
 
 gint export_list_to_mbox(GSList *mlist, const gchar *mbox)
@@ -538,37 +549,30 @@ gint export_list_to_mbox(GSList *mlist, const gchar *mbox)
        if (g_file_test(mbox, G_FILE_TEST_EXISTS) == TRUE) {
                if (alertpanel_full(_("Overwrite mbox file"),
                                        _("This file already exists. Do you want to overwrite it?"),
-                                       GTK_STOCK_CANCEL, _("Overwrite"), NULL, FALSE,
-                                       NULL, ALERT_WARNING, G_ALERTDEFAULT)
+                                       GTK_STOCK_CANCEL, _("Overwrite"), NULL,
+                                       ALERTFOCUS_FIRST, FALSE, NULL, ALERT_WARNING)
                                != G_ALERTALTERNATE) {
                        return -2;
                }
        }
 
-       if ((mbox_fp = g_fopen(mbox, "wb")) == NULL) {
-               FILE_OP_ERROR(mbox, "fopen");
+       if ((mbox_fp = claws_fopen(mbox, "wb")) == NULL) {
+               FILE_OP_ERROR(mbox, "claws_fopen");
                alertpanel_error(_("Could not create mbox file:\n%s\n"), mbox);
                return -1;
        }
 
-#ifdef HAVE_FGETS_UNLOCKED
-       flockfile(mbox_fp);
-#endif
-
-       statuswindow_print_all(_("Exporting to mbox..."));
+       statusbar_print_all(_("Exporting to mbox..."));
        for (cur = mlist; cur != NULL; cur = cur->next) {
                int len;
                gchar buft[BUFFSIZE];
                msginfo = (MsgInfo *)cur->data;
 
-               msg_fp = procmsg_open_message(msginfo);
+               msg_fp = procmsg_open_message(msginfo, TRUE);
                if (!msg_fp) {
                        continue;
                }
 
-#ifdef HAVE_FGETS_UNLOCKED
-               flockfile(msg_fp);
-#endif
                strncpy2(buf,
                         msginfo->from ? msginfo->from :
                         cur_account && cur_account->address ?
@@ -579,41 +583,32 @@ gint export_list_to_mbox(GSList *mlist, const gchar *mbox)
                if (fprintf(mbox_fp, "From %s %s",
                        buf, ctime_r(&msginfo->date_t, buft)) < 0) {
                        err = -1;
-#ifdef HAVE_FGETS_UNLOCKED
-                       funlockfile(msg_fp);
-#endif
-                       fclose(msg_fp);
+                       claws_fclose(msg_fp);
                        goto out;
                }
 
                buf[0] = '\0';
                
                /* write email to mboxrc */
-               while (SC_FGETS(buf, sizeof(buf), msg_fp) != NULL) {
+               while (claws_fgets(buf, sizeof(buf), msg_fp) != NULL) {
                        /* quote any From, >From, >>From, etc., according to mbox format specs */
                        int offset;
 
                        offset = 0;
                        /* detect leading '>' char(s) */
-                       while ((buf[offset] == '>')) {
+                       while (buf[offset] == '>') {
                                offset++;
                        }
                        if (!strncmp(buf+offset, "From ", 5)) {
-                               if (SC_FPUTC('>', mbox_fp) == EOF) {
+                               if (claws_fputc('>', mbox_fp) == EOF) {
                                        err = -1;
-#ifdef HAVE_FGETS_UNLOCKED
-                                       funlockfile(msg_fp);
-#endif
-                                       fclose(msg_fp);
+                                       claws_fclose(msg_fp);
                                        goto out;
                                }
                        }
-                       if (SC_FPUTS(buf, mbox_fp) == EOF) {
+                       if (claws_fputs(buf, mbox_fp) == EOF) {
                                err = -1;
-#ifdef HAVE_FGETS_UNLOCKED
-                               funlockfile(msg_fp);
-#endif
-                               fclose(msg_fp);
+                               claws_fclose(msg_fp);
                                goto out;
                        }
                }
@@ -623,31 +618,22 @@ gint export_list_to_mbox(GSList *mlist, const gchar *mbox)
                if (len > 0) {
                        len--;
                        if ((buf[len] != '\n') && (buf[len] != '\r')) {
-                               if (SC_FPUTC('\n', mbox_fp) == EOF) {
+                               if (claws_fputc('\n', mbox_fp) == EOF) {
                                        err = -1;
-#ifdef HAVE_FGETS_UNLOCKED
-                                       funlockfile(msg_fp);
-#endif
-                                       fclose(msg_fp);
+                                       claws_fclose(msg_fp);
                                        goto out;
                                }
                        }
                }
 
                /* add a trailing empty line */
-               if (SC_FPUTC('\n', mbox_fp) == EOF) {
+               if (claws_fputc('\n', mbox_fp) == EOF) {
                        err = -1;
-#ifdef HAVE_FGETS_UNLOCKED
-                       funlockfile(msg_fp);
-#endif
-                       fclose(msg_fp);
+                       claws_fclose(msg_fp);
                        goto out;
                }
 
-#ifdef HAVE_FGETS_UNLOCKED
-               funlockfile(msg_fp);
-#endif
-               fclose(msg_fp);
+               claws_safe_fclose(msg_fp);
                statusbar_progress_all(msgs++,total, 500);
                if (msgs%500 == 0)
                        GTK_EVENTS_FLUSH();
@@ -655,12 +641,9 @@ gint export_list_to_mbox(GSList *mlist, const gchar *mbox)
 
 out:
        statusbar_progress_all(0,0,0);
-       statuswindow_pop_all();
+       statusbar_pop_all();
 
-#ifdef HAVE_FGETS_UNLOCKED
-       funlockfile(mbox_fp);
-#endif
-       fclose(mbox_fp);
+       claws_safe_fclose(mbox_fp);
 
        return err;
 }
@@ -672,9 +655,9 @@ gint export_to_mbox(FolderItem *src, const gchar *mbox)
        GSList *mlist;
        gint ret;
        
-       g_return_val_if_fail(src != NULL, -1);
-       g_return_val_if_fail(src->folder != NULL, -1);
-       g_return_val_if_fail(mbox != NULL, -1);
+       cm_return_val_if_fail(src != NULL, -1);
+       cm_return_val_if_fail(src->folder != NULL, -1);
+       cm_return_val_if_fail(mbox != NULL, -1);
 
        debug_print("Exporting messages from %s into %s...\n",
                    src->path, mbox);