From 0aa1465bbcecdc1320268966eea8437aaa1ae1f6 Mon Sep 17 00:00:00 2001
From: Wim Taymans <wim.taymans@collabora.co.uk>
Date: Thu, 23 Jun 2011 18:03:22 +0200
Subject: [PATCH] query: add method to check for metadata

Add a method to check if a certain metadata is supported in the ALLOCATION
query.
---
 gst/gstquery.c | 36 ++++++++++++++++++++++++++++++++++++
 gst/gstquery.h |  1 +
 2 files changed, 37 insertions(+)

diff --git a/gst/gstquery.c b/gst/gstquery.c
index 9c308be059..7fcbf2c06f 100644
--- a/gst/gstquery.c
+++ b/gst/gstquery.c
@@ -1682,6 +1682,7 @@ gst_query_add_allocation_meta (GstQuery * query, const gchar * api)
   GstStructure *structure;
 
   g_return_if_fail (GST_QUERY_TYPE (query) == GST_QUERY_ALLOCATION);
+  g_return_if_fail (api != NULL);
   g_return_if_fail (gst_query_is_writable (query));
 
   structure = GST_QUERY_STRUCTURE (query);
@@ -1767,6 +1768,41 @@ gst_query_parse_nth_allocation_meta (GstQuery * query, guint index)
   return ret;
 }
 
+/**
+ * gst_query_has_allocation_meta
+ * @query: a GST_QUERY_ALLOCATION type query #GstQuery
+ * @api: the metadata API
+ *
+ * Check if @query has metadata @api set.
+ *
+ * Returns: TRUE when @api is in the list of metadata.
+ */
+gboolean
+gst_query_has_allocation_meta (GstQuery * query, const gchar * api)
+{
+  const GValue *value;
+  GstStructure *structure;
+
+  g_return_val_if_fail (GST_QUERY_TYPE (query) == GST_QUERY_ALLOCATION, FALSE);
+  g_return_val_if_fail (api != NULL, FALSE);
+
+  structure = GST_QUERY_STRUCTURE (query);
+  value = gst_structure_id_get_value (structure, GST_QUARK (META));
+  if (value) {
+    GValueArray *array;
+    GValue *api_value;
+    guint i;
+
+    array = (GValueArray *) g_value_get_boxed (value);
+    for (i = 0; i < array->n_values; i++) {
+      api_value = g_value_array_get_nth (array, i);
+      if (!strcmp (api, g_value_get_string (api_value)))
+        return TRUE;
+    }
+  }
+  return FALSE;
+}
+
 /**
  * gst_query_add_allocation_memory
  * @query: a GST_QUERY_ALLOCATION type query #GstQuery
diff --git a/gst/gstquery.h b/gst/gstquery.h
index 96c5506ac7..7b83cbc143 100644
--- a/gst/gstquery.h
+++ b/gst/gstquery.h
@@ -363,6 +363,7 @@ void            gst_query_parse_allocation_params (GstQuery *query, guint *size,
 void            gst_query_add_allocation_meta       (GstQuery *query, const gchar *api);
 guint           gst_query_get_n_allocation_metas    (GstQuery *query);
 const gchar *   gst_query_parse_nth_allocation_meta (GstQuery *query, guint index);
+gboolean        gst_query_has_allocation_meta       (GstQuery *query, const gchar *api);
 
 void            gst_query_add_allocation_memory       (GstQuery *query, const gchar *alloc);
 guint           gst_query_get_n_allocation_memories   (GstQuery *query);