From f69283819a83fe3c5eacc177461b29adc6314fbc Mon Sep 17 00:00:00 2001
From: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Date: Fri, 20 Mar 2020 12:35:03 -0400
Subject: [PATCH] v4l2codecs: allocator: Add method to wait for more buffers

This add function to wait for buffers to get back into the pool along with a
set_flushing() method to allow unblocking this wait.
---
 sys/v4l2codecs/gstv4l2codecallocator.c | 39 ++++++++++++++++++++++++++
 sys/v4l2codecs/gstv4l2codecallocator.h |  9 ++++++
 2 files changed, 48 insertions(+)

diff --git a/sys/v4l2codecs/gstv4l2codecallocator.c b/sys/v4l2codecs/gstv4l2codecallocator.c
index c87f6ae9a3..46d6fa823a 100644
--- a/sys/v4l2codecs/gstv4l2codecallocator.c
+++ b/sys/v4l2codecs/gstv4l2codecallocator.c
@@ -45,6 +45,9 @@ struct _GstV4l2CodecAllocator
   gint pool_size;
   gboolean detached;
 
+  GCond buffer_cond;
+  gboolean flushing;
+
   GstV4l2Decoder *decoder;
   GstPadDirection direction;
 };
@@ -152,6 +155,7 @@ gst_v4l2_codec_allocator_release (GstMiniObject * mini_object)
   if (gst_v4l2_codec_buffer_release_mem (buf)) {
     GST_DEBUG_OBJECT (self, "Placing back buffer %i into pool", buf->index);
     g_queue_push_tail (&self->pool, buf);
+    g_cond_signal (&self->buffer_cond);
   }
 
   GST_OBJECT_UNLOCK (self);
@@ -196,6 +200,7 @@ failed:
 static void
 gst_v4l2_codec_allocator_init (GstV4l2CodecAllocator * self)
 {
+  g_cond_init (&self->buffer_cond);
 }
 
 static void
@@ -220,6 +225,8 @@ gst_v4l2_codec_allocator_finalize (GObject * object)
   if (!self->detached)
     gst_v4l2_decoder_request_buffers (self->decoder, self->direction, 0);
 
+  g_cond_clear (&self->buffer_cond);
+
   G_OBJECT_CLASS (gst_v4l2_codec_allocator_parent_class)->finalize (object);
 }
 
@@ -273,6 +280,27 @@ gst_v4l2_codec_allocator_alloc (GstV4l2CodecAllocator * self)
   return mem;
 }
 
+gboolean
+gst_v4l2_codec_allocator_create_buffer (GstV4l2CodecAllocator * self)
+{
+  /* TODO implement */
+  return FALSE;
+}
+
+gboolean
+gst_v4l2_codec_allocator_wait_for_buffer (GstV4l2CodecAllocator * self)
+{
+  gboolean ret;
+
+  GST_OBJECT_LOCK (self);
+  while (self->pool.length == 0 && !self->flushing)
+    g_cond_wait (&self->buffer_cond, GST_OBJECT_GET_LOCK (self));
+  ret = !self->flushing;
+  GST_OBJECT_UNLOCK (self);
+
+  return ret;
+}
+
 gboolean
 gst_v4l2_codec_allocator_prepare_buffer (GstV4l2CodecAllocator * self,
     GstBuffer * gstbuf)
@@ -324,6 +352,17 @@ gst_v4l2_codec_allocator_detach (GstV4l2CodecAllocator * self)
   GST_OBJECT_UNLOCK (self);
 }
 
+void
+gst_v4l2_codec_allocator_set_flushing (GstV4l2CodecAllocator * self,
+    gboolean flushing)
+{
+  GST_OBJECT_LOCK (self);
+  self->flushing = flushing;
+  if (flushing)
+    g_cond_broadcast (&self->buffer_cond);
+  GST_OBJECT_UNLOCK (self);
+}
+
 guint32
 gst_v4l2_codec_memory_get_index (GstMemory * mem)
 {
diff --git a/sys/v4l2codecs/gstv4l2codecallocator.h b/sys/v4l2codecs/gstv4l2codecallocator.h
index 24cf984f27..97fe1d2c41 100644
--- a/sys/v4l2codecs/gstv4l2codecallocator.h
+++ b/sys/v4l2codecs/gstv4l2codecallocator.h
@@ -38,6 +38,12 @@ GstV4l2CodecAllocator  *gst_v4l2_codec_allocator_new (GstV4l2Decoder * decoder,
 
 GstMemory              *gst_v4l2_codec_allocator_alloc (GstV4l2CodecAllocator * allocator);
 
+
+
+gboolean                gst_v4l2_codec_allocator_create_buffer (GstV4l2CodecAllocator * self);
+
+gboolean                gst_v4l2_codec_allocator_wait_for_buffer (GstV4l2CodecAllocator * self);
+
 gboolean                gst_v4l2_codec_allocator_prepare_buffer (GstV4l2CodecAllocator * allocator,
                                                                  GstBuffer * buffer);
 
@@ -45,6 +51,9 @@ guint                   gst_v4l2_codec_allocator_get_pool_size (GstV4l2CodecAllo
 
 void                    gst_v4l2_codec_allocator_detach (GstV4l2CodecAllocator * self);
 
+void                    gst_v4l2_codec_allocator_set_flushing (GstV4l2CodecAllocator * self,
+                                                               gboolean flushing);
+
 guint32                 gst_v4l2_codec_memory_get_index (GstMemory * mem);
 
 #endif /* _GST_V4L2_CODECS_ALLOCATOR_H_ */