fetcher: Track outstanding requests with a table

Track outstanding HTTP requests in a table for easier debugging.

Also fixes a bug discussed in https://bugzilla.gnome.org/755224
where the outstanding request counter was not decremented in the
event of an error, which could result in the fetcher hitting its
max request limit and locking up.

The bug is fixed by removing the request struct from the table in
pending_uri_free(), which is always called regardless of error,
so the outstanding request count is always accurate.

diff --git a/src/libostree/ostree-fetcher.c b/src/libostree/ostree-fetcher.c
index fbfc0aeca7bca08c87f1f7a3000e173e6b23c5fd..904c58061cfcf9a324a8c292d38a4e9df869f42a 100644 (file)
--- a/src/libostree/ostree-fetcher.c
+++ b/src/libostree/ostree-fetcher.c
@@ -58,30 +58,6 @@ typedef struct {
   GTask *task;
 } OstreeFetcherPendingURI;
 
-static int
-pending_task_compare (gconstpointer a,
-                      gconstpointer b,
-                      gpointer unused)
-{
-  gint priority_a = g_task_get_priority (G_TASK (a));
-  gint priority_b = g_task_get_priority (G_TASK (b));
-
-  return (priority_a == priority_b) ? 0 :
-         (priority_a < priority_b) ? -1 : 1;
-}
-
-static void
-pending_uri_free (OstreeFetcherPendingURI *pending)
-{
-  soup_uri_free (pending->uri);
-  g_clear_object (&pending->self);
-  g_clear_object (&pending->request);
-  g_clear_object (&pending->request_body);
-  g_free (pending->out_tmpfile);
-  g_clear_object (&pending->out_stream);
-  g_free (pending);
-}
-
 struct OstreeFetcher
 {
   GObject parent_instance;
@@ -101,13 +77,39 @@ struct OstreeFetcher
   guint total_requests;
 
   /* Queue for libsoup, see bgo#708591 */
-  gint outstanding;
   GQueue pending_queue;
+  GHashTable *outstanding;
   gint max_outstanding;
 };
 
 G_DEFINE_TYPE (OstreeFetcher, _ostree_fetcher, G_TYPE_OBJECT)
 
+static int
+pending_task_compare (gconstpointer a,
+                      gconstpointer b,
+                      gpointer unused)
+{
+  gint priority_a = g_task_get_priority (G_TASK (a));
+  gint priority_b = g_task_get_priority (G_TASK (b));
+
+  return (priority_a == priority_b) ? 0 :
+         (priority_a < priority_b) ? -1 : 1;
+}
+
+static void
+pending_uri_free (OstreeFetcherPendingURI *pending)
+{
+  g_hash_table_remove (pending->self->outstanding, pending);
+
+  soup_uri_free (pending->uri);
+  g_clear_object (&pending->self);
+  g_clear_object (&pending->request);
+  g_clear_object (&pending->request_body);
+  g_free (pending->out_tmpfile);
+  g_clear_object (&pending->out_stream);
+  g_free (pending);
+}
+
 static void
 _ostree_fetcher_finalize (GObject *object)
 {
@@ -124,6 +126,8 @@ _ostree_fetcher_finalize (GObject *object)
   while (!g_queue_is_empty (&self->pending_queue))
     g_object_unref (g_queue_pop_head (&self->pending_queue));
 
+  g_hash_table_destroy (self->outstanding);
+
   G_OBJECT_CLASS (_ostree_fetcher_parent_class)->finalize (object);
 }
 
@@ -199,6 +203,8 @@ _ostree_fetcher_init (OstreeFetcher *self)
   self->sending_messages = g_hash_table_new_full (NULL, NULL, NULL,
                                                   (GDestroyNotify)g_object_unref);
   self->output_stream_set = g_hash_table_new_full (NULL, NULL, NULL, (GDestroyNotify)g_object_unref);
+
+  self->outstanding = g_hash_table_new_full (NULL, NULL, NULL, NULL);
 }
 
 OstreeFetcher *
@@ -272,7 +278,7 @@ ostree_fetcher_process_pending_queue (OstreeFetcher *self)
 {
 
   while (g_queue_peek_head (&self->pending_queue) != NULL &&
-         self->outstanding < self->max_outstanding)
+         g_hash_table_size (self->outstanding) < self->max_outstanding)
     {
       GTask *task;
       OstreeFetcherPendingURI *pending;
@@ -283,7 +289,9 @@ ostree_fetcher_process_pending_queue (OstreeFetcher *self)
       pending = g_task_get_task_data (task);
       cancellable = g_task_get_cancellable (task);
 
-      self->outstanding++;
+      /* pending_uri_free() removes this. */
+      g_hash_table_add (self->outstanding, pending);
+
       soup_request_send_async (pending->request,
                                cancellable,
                                on_request_sent,
@@ -321,7 +329,6 @@ finish_stream (OstreeFetcherPendingURI *pending,
   /* Now that we've finished downloading, continue with other queued
    * requests.
    */
-  pending->self->outstanding--;
   ostree_fetcher_process_pending_queue (pending->self);
 
   if (stbuf.st_size < pending->content_length)