bufferpool: handle metadata in the pool

Mark all metadata on the allocated buffers with a POOLED flag. When a buffer
returns to the pool, remove all metadata that did not have the POOLED flag. This
makes sure that we never leave unknown metadata to the buffers in the pool.

diff --git a/gst/gstbufferpool.c b/gst/gstbufferpool.c
index 66b6e05..07fbbf0 100644 (file)
--- a/gst/gstbufferpool.c
+++ b/gst/gstbufferpool.c
@@ -176,6 +176,14 @@ default_alloc_buffer (GstBufferPool * pool, GstBuffer ** buffer,
   return GST_FLOW_OK;
 }
 
+static gboolean
+mark_meta_pooled (GstBuffer * buffer, GstMeta ** meta, gpointer user_data)
+{
+  GST_META_FLAG_SET (*meta, GST_META_FLAG_POOLED);
+
+  return TRUE;
+}
+
 /* the default implementation for preallocating the buffers
  * in the pool */
 static gboolean
@@ -198,6 +206,7 @@ default_start (GstBufferPool * pool)
     if (pclass->alloc_buffer (pool, &buffer, NULL) != GST_FLOW_OK)
       goto alloc_failed;
 
+    gst_buffer_foreach_meta (buffer, mark_meta_pooled, pool);
     GST_LOG_OBJECT (pool, "prealloced buffer %d: %p", i, buffer);
     /* release to the queue, we call the vmethod directly, we don't need to do
      * the other refcount handling right now. */
@@ -802,6 +811,10 @@ default_acquire_buffer (GstBufferPool * pool, GstBuffer ** buffer,
       /* no max_buffers, we allocate some more */
       if (G_LIKELY (pclass->alloc_buffer)) {
         result = pclass->alloc_buffer (pool, buffer, params);
+        if (result == GST_FLOW_OK && *buffer)
+          gst_buffer_foreach_meta (*buffer, mark_meta_pooled, pool);
+        else
+          result = GST_FLOW_ERROR;
       } else
         result = GST_FLOW_NOT_SUPPORTED;
       GST_LOG_OBJECT (pool, "alloc buffer %p", *buffer);
@@ -919,6 +932,14 @@ default_release_buffer (GstBufferPool * pool, GstBuffer * buffer)
   gst_poll_write_control (pool->poll);
 }
 
+static gboolean
+remove_meta_unpooled (GstBuffer * buffer, GstMeta ** meta, gpointer user_data)
+{
+  if (!GST_META_FLAG_IS_SET (*meta, GST_META_FLAG_POOLED))
+    *meta = NULL;
+  return TRUE;
+}
+
 /**
  * gst_buffer_pool_release_buffer:
  * @pool: a #GstBufferPool
@@ -943,6 +964,9 @@ gst_buffer_pool_release_buffer (GstBufferPool * pool, GstBuffer * buffer)
   if (!G_ATOMIC_POINTER_COMPARE_AND_EXCHANGE (&buffer->pool, pool, NULL))
     return;
 
+  /* remove all metadata without the POOLED flag */
+  gst_buffer_foreach_meta (buffer, remove_meta_unpooled, pool);
+
   pclass = GST_BUFFER_POOL_GET_CLASS (pool);
 
   if (G_LIKELY (pclass->release_buffer))