lib: Add an API to find a message by filename.

[notmuch] / lib / database.cc

diff --git a/lib/database.cc b/lib/database.cc
index 9c2f4ecdc58ff2bcb6de93eba16b8ddc3dfd0b00..f8b95bc46f5fcacf61839c30b4b1cf17a124c9f4 100644 (file)
--- a/lib/database.cc
+++ b/lib/database.cc
@@ -273,6 +273,8 @@ notmuch_status_to_string (notmuch_status_t status)
        return "Tag value is too long (exceeds NOTMUCH_TAG_MAX)";
     case NOTMUCH_STATUS_UNBALANCED_FREEZE_THAW:
        return "Unbalanced number of calls to notmuch_message_freeze/thaw";
+    case NOTMUCH_STATUS_UNBALANCED_ATOMIC:
+       return "Unbalanced number of calls to notmuch_database_begin_atomic/end_atomic";
     default:
     case NOTMUCH_STATUS_LAST_STATUS:
        return "Unknown error status value";
@@ -611,6 +613,7 @@ notmuch_database_open (const char *path,
 
     notmuch->needs_upgrade = FALSE;
     notmuch->mode = mode;
+    notmuch->atomic_nesting = 0;
     try {
        string last_thread_id;
 
@@ -974,6 +977,61 @@ notmuch_database_upgrade (notmuch_database_t *notmuch,
     return NOTMUCH_STATUS_SUCCESS;
 }
 
+notmuch_status_t
+notmuch_database_begin_atomic (notmuch_database_t *notmuch)
+{
+    if (notmuch->mode == NOTMUCH_DATABASE_MODE_READ_ONLY ||
+       notmuch->atomic_nesting > 0)
+       goto DONE;
+
+    try {
+       (static_cast <Xapian::WritableDatabase *> (notmuch->xapian_db))->begin_transaction (false);
+    } catch (const Xapian::Error &error) {
+       fprintf (stderr, "A Xapian exception occurred beginning transaction: %s.\n",
+                error.get_msg().c_str());
+       notmuch->exception_reported = TRUE;
+       return NOTMUCH_STATUS_XAPIAN_EXCEPTION;
+    }
+
+DONE:
+    notmuch->atomic_nesting++;
+    return NOTMUCH_STATUS_SUCCESS;
+}
+
+notmuch_status_t
+notmuch_database_end_atomic (notmuch_database_t *notmuch)
+{
+    Xapian::WritableDatabase *db;
+
+    if (notmuch->atomic_nesting == 0)
+       return NOTMUCH_STATUS_UNBALANCED_ATOMIC;
+
+    if (notmuch->mode == NOTMUCH_DATABASE_MODE_READ_ONLY ||
+       notmuch->atomic_nesting > 1)
+       goto DONE;
+
+    db = static_cast <Xapian::WritableDatabase *> (notmuch->xapian_db);
+    try {
+       db->commit_transaction ();
+
+       /* This is a hack for testing.  Xapian never flushes on a
+        * non-flushed commit, even if the flush threshold is 1.
+        * However, we rely on flushing to test atomicity. */
+       const char *thresh = getenv ("XAPIAN_FLUSH_THRESHOLD");
+       if (thresh && atoi (thresh) == 1)
+           db->commit ();
+    } catch (const Xapian::Error &error) {
+       fprintf (stderr, "A Xapian exception occurred committing transaction: %s.\n",
+                error.get_msg().c_str());
+       notmuch->exception_reported = TRUE;
+       return NOTMUCH_STATUS_XAPIAN_EXCEPTION;
+    }
+
+DONE:
+    notmuch->atomic_nesting--;
+    return NOTMUCH_STATUS_SUCCESS;
+}
+
 /* We allow the user to use arbitrarily long paths for directories. But
  * we have a term-length limit. So if we exceed that, we'll use the
  * SHA-1 of the path for the database term.
@@ -1689,72 +1747,60 @@ notmuch_status_t
 notmuch_database_remove_message (notmuch_database_t *notmuch,
                                 const char *filename)
 {
-    Xapian::WritableDatabase *db;
+    notmuch_message_t *message =
+       notmuch_database_find_message_by_filename (notmuch, filename);
+    notmuch_status_t status = NOTMUCH_STATUS_SUCCESS;
+
+    if (message) {
+           status = _notmuch_message_remove_filename (message, filename);
+           if (status == NOTMUCH_STATUS_SUCCESS)
+               _notmuch_message_delete (message);
+           else if (status == NOTMUCH_STATUS_DUPLICATE_MESSAGE_ID)
+               _notmuch_message_sync (message);
+    }
+
+    return status;
+}
+
+notmuch_message_t *
+notmuch_database_find_message_by_filename (notmuch_database_t *notmuch,
+                                          const char *filename)
+{
     void *local;
     const char *prefix = _find_prefix ("file-direntry");
     char *direntry, *term;
     Xapian::PostingIterator i, end;
-    Xapian::Document document;
+    notmuch_message_t *message = NULL;
     notmuch_status_t status;
 
-    status = _notmuch_database_ensure_writable (notmuch);
-    if (status)
-       return status;
-
     local = talloc_new (notmuch);
 
-    db = static_cast <Xapian::WritableDatabase *> (notmuch->xapian_db);
-
     try {
-
        status = _notmuch_database_filename_to_direntry (local, notmuch,
                                                         filename, &direntry);
        if (status)
-           return status;
+           return NULL;
 
        term = talloc_asprintf (local, "%s%s", prefix, direntry);
 
        find_doc_ids_for_term (notmuch, term, &i, &end);
 
-       for ( ; i != end; i++) {
-           Xapian::TermIterator j;
-           notmuch_message_t *message;
+       if (i != end) {
            notmuch_private_status_t private_status;
 
-           message = _notmuch_message_create (local, notmuch,
+           message = _notmuch_message_create (notmuch, notmuch,
                                               *i, &private_status);
-           if (message == NULL)
-               return COERCE_STATUS (private_status,
-                                     "Inconsistent document ID in datbase.");
-
-           _notmuch_message_remove_filename (message, filename);
-           _notmuch_message_sync (message);
-
-           /* Take care to find document after sync'ing filename removal. */
-           document = find_document_for_doc_id (notmuch, *i);
-           j = document.termlist_begin ();
-           j.skip_to (prefix);
-
-           /* Was this the last file-direntry in the message? */
-           if (j == document.termlist_end () ||
-               strncmp ((*j).c_str (), prefix, strlen (prefix)))
-           {
-               db->delete_document (document.get_docid ());
-               status = NOTMUCH_STATUS_SUCCESS;
-           } else {
-               status = NOTMUCH_STATUS_DUPLICATE_MESSAGE_ID;
-           }
        }
     } catch (const Xapian::Error &error) {
-       fprintf (stderr, "Error: A Xapian exception occurred removing message: %s\n",
+       fprintf (stderr, "Error: A Xapian exception occurred finding message by filename: %s\n",
                 error.get_msg().c_str());
        notmuch->exception_reported = TRUE;
-       status = NOTMUCH_STATUS_XAPIAN_EXCEPTION;
+       message = NULL;
     }
 
     talloc_free (local);
 
-    return status;
+    return message;
 }
 
 notmuch_string_list_t *