+/* Is the given filename within a maildir directory?
+ *
+ * Specifically, is the final directory component of 'filename' either
+ * "cur" or "new". If so, return a pointer to that final directory
+ * component within 'filename'. If not, return NULL.
+ *
+ * A non-NULL return value is guaranteed to be a valid string pointer
+ * pointing to the characters "new/" or "cur/", (but not
+ * NUL-terminated).
+ */
+static const char *
+_filename_is_in_maildir (const char *filename)
+{
+ const char *slash, *dir = NULL;
+
+ /* Find the last '/' separating directory from filename. */
+ slash = strrchr (filename, '/');
+ if (slash == NULL)
+ return NULL;
+
+ /* Jump back 4 characters to where the previous '/' will be if the
+ * directory is named "cur" or "new". */
+ if (slash - filename < 4)
+ return NULL;
+
+ slash -= 4;
+
+ if (*slash != '/')
+ return NULL;
+
+ dir = slash + 1;
+
+ if (STRNCMP_LITERAL (dir, "cur/") == 0 ||
+ STRNCMP_LITERAL (dir, "new/") == 0)
+ {
+ return dir;
+ }
+
+ return NULL;
+}
+
+notmuch_status_t
+notmuch_message_maildir_flags_to_tags (notmuch_message_t *message)
+{
+ const char *flags;
+ notmuch_status_t status;
+ notmuch_filenames_t *filenames;
+ const char *filename, *dir;
+ char *combined_flags = talloc_strdup (message, "");
+ unsigned i;
+ int seen_maildir_info = 0;
+
+ for (filenames = notmuch_message_get_filenames (message);
+ notmuch_filenames_valid (filenames);
+ notmuch_filenames_move_to_next (filenames))
+ {
+ filename = notmuch_filenames_get (filenames);
+ dir = _filename_is_in_maildir (filename);
+
+ if (! dir)
+ continue;
+
+ flags = strstr (filename, ":2,");
+ if (flags) {
+ seen_maildir_info = 1;
+ flags += 3;
+ combined_flags = talloc_strdup_append (combined_flags, flags);
+ } else if (STRNCMP_LITERAL (dir, "new/") == 0) {
+ /* Messages are delivered to new/ with no "info" part, but
+ * they effectively have default maildir flags. According
+ * to the spec, we should ignore the info part for
+ * messages in new/, but some MUAs (mutt) can set maildir
+ * flags on messages in new/, so we're liberal in what we
+ * accept. */
+ seen_maildir_info = 1;
+ }
+ }
+
+ /* If none of the filenames have any maildir info field (not even
+ * an empty info with no flags set) then there's no information to
+ * go on, so do nothing. */
+ if (! seen_maildir_info)
+ return NOTMUCH_STATUS_SUCCESS;
+
+ status = notmuch_message_freeze (message);
+ if (status)
+ return status;
+
+ for (i = 0; i < ARRAY_SIZE(flag2tag); i++) {
+ if ((strchr (combined_flags, flag2tag[i].flag) != NULL)
+ ^
+ flag2tag[i].inverse)
+ {
+ status = notmuch_message_add_tag (message, flag2tag[i].tag);
+ } else {
+ status = notmuch_message_remove_tag (message, flag2tag[i].tag);
+ }
+ if (status)
+ return status;
+ }
+ status = notmuch_message_thaw (message);
+
+ talloc_free (combined_flags);
+
+ return status;
+}
+
+/* From the set of tags on 'message' and the flag2tag table, compute a
+ * set of maildir-flag actions to be taken, (flags that should be
+ * either set or cleared).
+ *
+ * The result is returned as two talloced strings: to_set, and to_clear
+ */
+static void
+_get_maildir_flag_actions (notmuch_message_t *message,
+ char **to_set_ret,
+ char **to_clear_ret)
+{
+ char *to_set, *to_clear;
+ notmuch_tags_t *tags;
+ const char *tag;
+ unsigned i;
+
+ to_set = talloc_strdup (message, "");
+ to_clear = talloc_strdup (message, "");
+
+ /* First, find flags for all set tags. */
+ for (tags = notmuch_message_get_tags (message);
+ notmuch_tags_valid (tags);
+ notmuch_tags_move_to_next (tags))
+ {
+ tag = notmuch_tags_get (tags);
+
+ for (i = 0; i < ARRAY_SIZE (flag2tag); i++) {
+ if (strcmp (tag, flag2tag[i].tag) == 0) {
+ if (flag2tag[i].inverse)
+ to_clear = talloc_asprintf_append (to_clear,
+ "%c",
+ flag2tag[i].flag);
+ else
+ to_set = talloc_asprintf_append (to_set,
+ "%c",
+ flag2tag[i].flag);
+ }
+ }
+ }
+
+ /* Then, find the flags for all tags not present. */
+ for (i = 0; i < ARRAY_SIZE (flag2tag); i++) {
+ if (flag2tag[i].inverse) {
+ if (strchr (to_clear, flag2tag[i].flag) == NULL)
+ to_set = talloc_asprintf_append (to_set, "%c", flag2tag[i].flag);
+ } else {
+ if (strchr (to_set, flag2tag[i].flag) == NULL)
+ to_clear = talloc_asprintf_append (to_clear, "%c", flag2tag[i].flag);
+ }
+ }
+
+ *to_set_ret = to_set;
+ *to_clear_ret = to_clear;
+}
+
+/* Given 'filename' and a set of maildir flags to set and to clear,
+ * compute the new maildir filename.
+ *
+ * If the existing filename is in the directory "new", the new
+ * filename will be in the directory "cur", except for the case when
+ * no flags are changed and the existing filename does not contain
+ * maildir info (starting with ",2:").
+ *
+ * After a sequence of ":2," in the filename, any subsequent
+ * single-character flags will be added or removed according to the
+ * characters in flags_to_set and flags_to_clear. Any existing flags
+ * not mentioned in either string will remain. The final list of flags
+ * will be in ASCII order.
+ *
+ * If the original flags seem invalid, (repeated characters or
+ * non-ASCII ordering of flags), this function will return NULL
+ * (meaning that renaming would not be safe and should not occur).
+ */
+static char*
+_new_maildir_filename (void *ctx,
+ const char *filename,
+ const char *flags_to_set,
+ const char *flags_to_clear)
+{
+ const char *info, *flags;
+ unsigned int flag, last_flag;
+ char *filename_new, *dir;
+ char flag_map[128];
+ int flags_in_map = 0;
+ notmuch_bool_t flags_changed = FALSE;
+ unsigned int i;
+ char *s;
+
+ memset (flag_map, 0, sizeof (flag_map));
+
+ info = strstr (filename, ":2,");
+
+ if (info == NULL) {
+ info = filename + strlen(filename);
+ } else {
+ /* Loop through existing flags in filename. */
+ for (flags = info + 3, last_flag = 0;
+ *flags;
+ last_flag = flag, flags++)
+ {
+ flag = *flags;
+
+ /* Original flags not in ASCII order. Abort. */
+ if (flag < last_flag)
+ return NULL;
+
+ /* Non-ASCII flag. Abort. */
+ if (flag > sizeof(flag_map) - 1)
+ return NULL;
+
+ /* Repeated flag value. Abort. */
+ if (flag_map[flag])
+ return NULL;
+
+ flag_map[flag] = 1;
+ flags_in_map++;
+ }
+ }
+
+ /* Then set and clear our flags from tags. */
+ for (flags = flags_to_set; *flags; flags++) {
+ flag = *flags;
+ if (flag_map[flag] == 0) {
+ flag_map[flag] = 1;
+ flags_in_map++;
+ flags_changed = TRUE;
+ }
+ }
+
+ for (flags = flags_to_clear; *flags; flags++) {
+ flag = *flags;
+ if (flag_map[flag]) {
+ flag_map[flag] = 0;
+ flags_in_map--;
+ flags_changed = TRUE;
+ }
+ }
+
+ /* Messages in new/ without maildir info can be kept in new/ if no
+ * flags have changed. */
+ dir = (char *) _filename_is_in_maildir (filename);
+ if (dir && STRNCMP_LITERAL (dir, "new/") == 0 && !*info && !flags_changed)
+ return talloc_strdup (ctx, filename);
+
+ filename_new = (char *) talloc_size (ctx,
+ info - filename +
+ strlen (":2,") + flags_in_map + 1);
+ if (unlikely (filename_new == NULL))
+ return NULL;
+
+ strncpy (filename_new, filename, info - filename);
+ filename_new[info - filename] = '\0';
+
+ strcat (filename_new, ":2,");
+
+ s = filename_new + strlen (filename_new);
+ for (i = 0; i < sizeof (flag_map); i++)
+ {
+ if (flag_map[i]) {
+ *s = i;
+ s++;
+ }
+ }
+ *s = '\0';
+
+ /* If message is in new/ move it under cur/. */
+ dir = (char *) _filename_is_in_maildir (filename_new);
+ if (dir && STRNCMP_LITERAL (dir, "new/") == 0)
+ memcpy (dir, "cur/", 4);
+
+ return filename_new;
+}
+
+notmuch_status_t
+notmuch_message_tags_to_maildir_flags (notmuch_message_t *message)
+{
+ notmuch_filenames_t *filenames;
+ const char *filename;
+ char *filename_new;
+ char *to_set, *to_clear;
+ notmuch_status_t status = NOTMUCH_STATUS_SUCCESS;
+
+ _get_maildir_flag_actions (message, &to_set, &to_clear);
+
+ for (filenames = notmuch_message_get_filenames (message);
+ notmuch_filenames_valid (filenames);
+ notmuch_filenames_move_to_next (filenames))
+ {
+ filename = notmuch_filenames_get (filenames);
+
+ if (! _filename_is_in_maildir (filename))
+ continue;
+
+ filename_new = _new_maildir_filename (message, filename,
+ to_set, to_clear);
+ if (filename_new == NULL)
+ continue;
+
+ if (strcmp (filename, filename_new)) {
+ int err;
+ notmuch_status_t new_status;
+
+ err = rename (filename, filename_new);
+ if (err)
+ continue;
+
+ new_status = _notmuch_message_remove_filename (message,
+ filename);
+ /* Hold on to only the first error. */
+ if (! status && new_status
+ && new_status != NOTMUCH_STATUS_DUPLICATE_MESSAGE_ID) {
+ status = new_status;
+ continue;
+ }
+
+ new_status = _notmuch_message_add_filename (message,
+ filename_new);
+ /* Hold on to only the first error. */
+ if (! status && new_status) {
+ status = new_status;
+ continue;
+ }
+
+ _notmuch_message_sync (message);
+ }
+
+ talloc_free (filename_new);
+ }
+
+ talloc_free (to_set);
+ talloc_free (to_clear);
+
+ return status;
+}
+
+notmuch_status_t