database: Allowing storing multiple filenames for a single message ID.

The library interface is unchanged so far, (still just
notmuch_database_add_message), but internally, the old
_set_filename function is now _add_filename instead.

lib/database.cc

@@ -843,7 +843,6 @@ notmuch_database_get_directory_mtime (notmuch_database_t *notmuch,
     notmuch_private_status_t status;
     const char *db_path = NULL;
     time_t ret = 0;
-    void *local = talloc_new (notmuch);
 
     db_path = directory_db_path (path);
 
@@ -1188,24 +1187,25 @@ notmuch_database_add_message (notmuch_database_t *notmuch,
 	    goto DONE;
 	}
 
+	_notmuch_message_add_filename (message, filename);
+
 	/* Is this a newly created message object? */
 	if (private_status == NOTMUCH_PRIVATE_STATUS_NO_DOCUMENT_FOUND) {
-	    _notmuch_message_set_filename (message, filename);
 	    _notmuch_message_add_term (message, "type", "mail");
+
+	    ret = _notmuch_database_link_message (notmuch, message,
+						  message_file);
+	    if (ret)
+		goto DONE;
+
+	    date = notmuch_message_file_get_header (message_file, "date");
+	    _notmuch_message_set_date (message, date);
+
+	    _notmuch_message_index_file (message, filename);
 	} else {
 	    ret = NOTMUCH_STATUS_DUPLICATE_MESSAGE_ID;
-	    goto DONE;
 	}
 
-	ret = _notmuch_database_link_message (notmuch, message, message_file);
-	if (ret)
-	    goto DONE;
-
-	date = notmuch_message_file_get_header (message_file, "date");
-	_notmuch_message_set_date (message, date);
-
-	_notmuch_message_index_file (message, filename);
-
 	_notmuch_message_sync (message);
     } catch (const Xapian::Error &error) {
 	fprintf (stderr, "A Xapian exception occurred adding message: %s.\n",

lib/message.cc

@@ -385,15 +385,12 @@ notmuch_message_get_replies (notmuch_message_t *message)
     return _notmuch_messages_create (message->replies);
 }
 
-/* Set the filename for 'message' to 'filename'.
+/* Add an additional 'filename' for 'message'.
- *
- * XXX: We should still figure out if we think it's important to store
- * multiple filenames for email messages with identical message IDs.
  *
  * This change will not be reflected in the database until the next
  * call to _notmuch_message_set_sync. */
 notmuch_status_t
-_notmuch_message_set_filename (notmuch_message_t *message,
+_notmuch_message_add_filename (notmuch_message_t *message,
 			       const char *filename)
 {
     const char *relative, *directory, *basename;

lib/notmuch-private.h

@@ -211,7 +211,7 @@ _notmuch_message_gen_terms (notmuch_message_t *message,
 			    const char *text);
 
 notmuch_status_t
-_notmuch_message_set_filename (notmuch_message_t *message,
+_notmuch_message_add_filename (notmuch_message_t *message,
 			       const char *filename);
 
 void

lib/notmuch.h

@@ -698,14 +698,20 @@ notmuch_message_get_thread_id (notmuch_message_t *message);
 notmuch_messages_t *
 notmuch_message_get_replies (notmuch_message_t *message);
 
-/* Get the filename for the email corresponding to 'message'.
+/* Get a filename for the email corresponding to 'message'.
  *
  * The returned filename is an absolute filename, (the initial
  * component will match notmuch_database_get_path() ).
  *
  * The returned string belongs to the message so should not be
  * modified or freed by the caller (nor should it be referenced after
- * the message is destroyed). */
+ * the message is destroyed).
+ *
+ * Note: If this message corresponds to multiple files in the mail
+ * store, (that is, multiple files contain identical message IDs),
+ * this function will arbitrarily return a single one of those
+ * filenames.
+ */
 const char *
 notmuch_message_get_filename (notmuch_message_t *message);