From 1937d09a958b65d53f1fb8913b343dc65c4bfe38 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Sebastian=20Dr=C3=B6ge?= <sebastian@centricular.com>
Date: Thu, 12 Feb 2015 13:55:36 +0200
Subject: [PATCH] pad: Implement more useful default handling for the LATENCY
 query

Before we just took the values from the first pad that succeded the query,
now we accumulate the results of every sinkpad properly and return that
result.
---
 gst/gstpad.c | 106 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 105 insertions(+), 1 deletion(-)

diff --git a/gst/gstpad.c b/gst/gstpad.c
index dfa1eea..7083aca 100644
--- a/gst/gstpad.c
+++ b/gst/gstpad.c
@@ -3050,6 +3050,107 @@ done:
   return TRUE;
 }
 
+/* Default latency implementation */
+typedef struct
+{
+  gboolean live;
+  GstClockTime min, max;
+} LatencyFoldData;
+
+static gboolean
+query_latency_default_fold (const GValue * item, GValue * ret,
+    gpointer user_data)
+{
+  GstPad *pad = g_value_get_object (item);
+  LatencyFoldData *fold_data = user_data;
+  GstQuery *query;
+  gboolean res;
+
+  query = gst_query_new_latency ();
+  res = gst_pad_peer_query (pad, query);
+
+  if (res) {
+    gboolean live;
+    GstClockTime min, max;
+
+    gst_query_parse_latency (query, &live, &min, &max);
+
+    GST_LOG_OBJECT (pad, "got latency live:%s min:%" G_GINT64_FORMAT
+        " max:%" G_GINT64_FORMAT, live ? "true" : "false", min, max);
+
+    if (live) {
+      if (min > fold_data->min)
+        fold_data->min = min;
+
+      if (fold_data->max == GST_CLOCK_TIME_NONE)
+        fold_data->max = max;
+      else if (max < fold_data->max)
+        fold_data->max = max;
+
+      fold_data->live = TRUE;
+    }
+    g_value_set_boolean (ret, TRUE);
+  }
+  gst_query_unref (query);
+
+  return TRUE;
+}
+
+static gboolean
+gst_pad_query_latency_default (GstPad * pad, GstQuery * query)
+{
+  GstIterator *it;
+  GstIteratorResult res;
+  GValue ret = G_VALUE_INIT;
+  gboolean query_ret;
+  LatencyFoldData fold_data;
+
+  it = gst_pad_iterate_internal_links (pad);
+
+retry:
+  fold_data.live = FALSE;
+  fold_data.min = 0;
+  fold_data.max = GST_CLOCK_TIME_NONE;
+
+  g_value_init (&ret, G_TYPE_BOOLEAN);
+  g_value_set_boolean (&ret, FALSE);
+  res = gst_iterator_fold (it, query_latency_default_fold, &ret, &fold_data);
+  switch (res) {
+    case GST_ITERATOR_OK:
+      g_assert_not_reached ();
+      break;
+    case GST_ITERATOR_DONE:
+      break;
+    case GST_ITERATOR_ERROR:
+      g_value_set_boolean (&ret, FALSE);
+      break;
+    case GST_ITERATOR_RESYNC:
+      gst_iterator_resync (it);
+      goto retry;
+    default:
+      g_assert_not_reached ();
+      break;
+  }
+  gst_iterator_free (it);
+
+  query_ret = g_value_get_boolean (&ret);
+  if (query_ret) {
+    GST_LOG_OBJECT (pad, "got latency live:%s min:%" G_GINT64_FORMAT
+        " max:%" G_GINT64_FORMAT, fold_data.live ? "true" : "false",
+        fold_data.min, fold_data.max);
+
+    if (fold_data.min > fold_data.max) {
+      GST_ERROR_OBJECT (pad, "minimum latency bigger than maximum latency");
+    }
+
+    gst_query_set_latency (query, fold_data.live, fold_data.min, fold_data.max);
+  } else {
+    GST_LOG_OBJECT (pad, "latency query failed");
+  }
+
+  return query_ret;
+}
+
 typedef struct
 {
   GstQuery *query;
@@ -3105,10 +3206,13 @@ gst_pad_query_default (GstPad * pad, GstObject * parent, GstQuery * query)
       ret = gst_pad_query_caps_default (pad, query);
       forward = FALSE;
       break;
+    case GST_QUERY_LATENCY:
+      ret = gst_pad_query_latency_default (pad, query);
+      forward = FALSE;
+      break;
     case GST_QUERY_POSITION:
     case GST_QUERY_SEEKING:
     case GST_QUERY_FORMATS:
-    case GST_QUERY_LATENCY:
     case GST_QUERY_JITTER:
     case GST_QUERY_RATE:
     case GST_QUERY_CONVERT:
-- 
2.7.4