lib/thread: rewrite _parent_or_toplevel to use depths

[notmuch] / lib / thread.cc

diff --git a/lib/thread.cc b/lib/thread.cc
index 62dbd3b345482ccb901b8c05c135238f35bc0264..4f85a82934bbfe143d39b40cd05023e8b1893bd2 100644 (file)
--- a/lib/thread.cc
+++ b/lib/thread.cc
@@ -402,7 +402,7 @@ _parent_via_in_reply_to (notmuch_thread_t *thread, notmuch_message_t *message) {
     THREAD_DEBUG("checking message = %s in_reply_to=%s\n",
                 notmuch_message_get_message_id (message), in_reply_to);
 
-    if (in_reply_to && strlen (in_reply_to) &&
+    if (in_reply_to && (! EMPTY_STRING(in_reply_to)) &&
        g_hash_table_lookup_extended (thread->message_hash,
                                      in_reply_to, NULL,
                                      (void **) &parent)) {
@@ -413,22 +413,72 @@ _parent_via_in_reply_to (notmuch_thread_t *thread, notmuch_message_t *message) {
     }
 }
 
+static void
+_parent_or_toplevel (notmuch_thread_t *thread, notmuch_message_t *message)
+{
+    size_t max_depth = 0;
+    notmuch_message_t *new_parent;
+    notmuch_message_t *parent = NULL;
+    const notmuch_string_list_t *references =
+       _notmuch_message_get_references (message);
+
+    THREAD_DEBUG("trying to reparent via references: %s\n",
+                    notmuch_message_get_message_id (message));
+
+    for (notmuch_string_node_t *ref_node = references->head;
+        ref_node; ref_node = ref_node->next) {
+       THREAD_DEBUG("checking reference=%s\n", ref_node->string);
+       if ((g_hash_table_lookup_extended (thread->message_hash,
+                                          ref_node->string, NULL,
+                                          (void **) &new_parent))) {
+           size_t new_depth = _notmuch_message_get_thread_depth (new_parent);
+           THREAD_DEBUG("got depth %lu\n", new_depth);
+           if (new_depth > max_depth || !parent) {
+               THREAD_DEBUG("adding at depth %lu parent=%s\n", new_depth, ref_node->string);
+               max_depth = new_depth;
+               parent = new_parent;
+           }
+       }
+    }
+    if (parent) {
+       THREAD_DEBUG("adding reply %s to parent=%s\n",
+                notmuch_message_get_message_id (message),
+                notmuch_message_get_message_id (parent));
+       _notmuch_message_add_reply (parent, message);
+    } else {
+       THREAD_DEBUG("adding as toplevel %s\n",
+                notmuch_message_get_message_id (message));
+       _notmuch_message_list_add_message (thread->toplevel_list, message);
+    }
+}
+
 static void
 _resolve_thread_relationships (notmuch_thread_t *thread)
 {
     notmuch_message_node_t *node, *first_node;
     notmuch_message_t *message;
+    void *local;
+    notmuch_message_list_t *maybe_toplevel_list;
 
     first_node = thread->message_list->head;
     if (! first_node)
        return;
 
+    local = talloc_new (thread);
+    maybe_toplevel_list = _notmuch_message_list_create (local);
+
     for (node = first_node->next; node; node = node->next) {
        message = node->message;
        if (! _parent_via_in_reply_to (thread, message))
-           _notmuch_message_list_add_message (thread->toplevel_list, message);
+           _notmuch_message_list_add_message (maybe_toplevel_list, message);
     }
 
+    for (notmuch_messages_t *roots = _notmuch_messages_create (maybe_toplevel_list);
+        notmuch_messages_valid (roots);
+        notmuch_messages_move_to_next (roots)) {
+       notmuch_message_t *message = notmuch_messages_get (roots);
+       _parent_or_toplevel (thread, message);
+    }
     /*
      * if we reach the end of the list without finding a top-level
      * message, that means the thread is a cycle (or set of cycles)
@@ -439,7 +489,15 @@ _resolve_thread_relationships (notmuch_thread_t *thread)
        message = first_node->message;
         if (_notmuch_message_list_empty(thread->toplevel_list) ||
            ! _parent_via_in_reply_to (thread, message)) {
-           _notmuch_message_list_add_message (thread->toplevel_list, message);
+           /*
+            * If the oldest message happens to be in-reply-to a
+            * missing message, we only check for references if there
+            * is some other candidate for root message.
+            */
+           if (! _notmuch_message_list_empty (thread->toplevel_list))
+               _parent_or_toplevel (thread, message);
+           else
+               _notmuch_message_list_add_message (thread->toplevel_list, message);
        }
     }
 
@@ -459,6 +517,7 @@ _resolve_thread_relationships (notmuch_thread_t *thread)
      * correctly in the thread even when an intermediate message is
      * missing from the thread.
      */
+    talloc_free (local);
 }
 
 /* Create a new notmuch_thread_t object by finding the thread