lib: Simplify code flow in _resolve_message_id_to_thread_id

There are two primary cases in this function, (the message exists in
the database or it does not). Previously the code for these two cases
was split and intermingled with goto-spaghetti connections.

diff --git a/lib/database.cc b/lib/database.cc
index 9cd46d4fcb7ca3c85b6d7be8340cc6b60a1a2c56..d4e2f1ed4d705be14184178ab1612753b50ba6b5 100644 (file)
--- a/lib/database.cc
+++ b/lib/database.cc
@@ -1152,36 +1152,41 @@ _resolve_message_id_to_thread_id (notmuch_database_t *notmuch,
                                  const char *message_id)
 {
     notmuch_message_t *message;
                                  const char *message_id)
 {
     notmuch_message_t *message;

-    const char *ret = NULL;
+    string thread_id_string;
+    const char *thread_id;
+    char *metadata_key;
+    Xapian::WritableDatabase *db;

 
     message = notmuch_database_find_message (notmuch, message_id);
 
     message = notmuch_database_find_message (notmuch, message_id);

-    /* If we haven't seen that message yet then check if we have already
-     * generated a dummy id for it and stored it in the metadata.
-     * If not then we generate a new thread id.
-     * This ensures that we can thread messages even when we haven't received
-     * the root (yet?)
-     */
-    if (message == NULL) {
-        Xapian::WritableDatabase *db = static_cast <Xapian::WritableDatabase *> (notmuch->xapian_db);
-        char * metadata_key = _get_metadata_thread_id_key (ctx, message_id);
-        string thread_id = notmuch->xapian_db->get_metadata(metadata_key);
-        if (thread_id.empty()) {
-            ret = _notmuch_database_generate_thread_id(notmuch);
-            db->set_metadata(metadata_key, ret);
-        } else {
-            ret = thread_id.c_str();
-        }
-        talloc_free (metadata_key);
-        goto DONE;
-    }

 
 

-    ret = talloc_steal (ctx, notmuch_message_get_thread_id (message));
+    if (message) {
+       thread_id = talloc_steal (ctx, notmuch_message_get_thread_id (message));

 
 

-  DONE:
-    if (message)

        notmuch_message_destroy (message);
 
        notmuch_message_destroy (message);
 

-    return ret;
+       return thread_id;
+    }
+
+    /* Message has not been seen yet.
+     *
+     * We may have seen a reference to it already, in which case, we
+     * can return the thread ID stored in the metadata. Otherwise, we
+     * generate a new thread ID and store it there.
+     */
+    db = static_cast <Xapian::WritableDatabase *> (notmuch->xapian_db);
+    metadata_key = _get_metadata_thread_id_key (ctx, message_id);
+    thread_id_string = notmuch->xapian_db->get_metadata (metadata_key);
+
+    if (thread_id_string.empty()) {
+       thread_id = _notmuch_database_generate_thread_id (notmuch);
+       db->set_metadata (metadata_key, thread_id);
+    } else {
+       thread_id = thread_id_string.c_str();
+    }
+
+    talloc_free (metadata_key);
+
+    return thread_id;

 }
 
 static notmuch_status_t
 }
 
 static notmuch_status_t