[Spice-devel] [spice-server v3 01/10] sound: Rework spice_server_playback_get_buffer() error handling

[Christophe Fergeau]

The main goal of this commit is to avoid to dereference 'client' before
it's checked for NULL. This meant splitting one error condition in 2
separate ones.

This also sets default values for the 'frame' and 'num-samples'
out parameters so that we just have to return on error conditions.

Based on a patch from Frediano Ziglio <fziglio at redhat.com>

Signed-off-by: Christophe Fergeau <cfergeau at redhat.com>
---
 server/sound.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/server/sound.c b/server/sound.c
index bacd340..2165644 100644
--- a/server/sound.c
+++ b/server/sound.c
@@ -1166,11 +1166,14 @@ SPICE_GNUC_VISIBLE void spice_server_playback_get_buffer(SpicePlaybackInstance *
                                                          uint32_t **frame, uint32_t *num_samples)
 {
     SndChannelClient *client = sin->st->channel.connection;
-    PlaybackChannelClient *playback_client = SPICE_CONTAINEROF(client, PlaybackChannelClient, base);
 
-    if (!client || !playback_client->free_frames) {
-        *frame = NULL;
-        *num_samples = 0;
+    *frame = NULL;
+    *num_samples = 0;
+    if (!client) {
+        return;
+    }
+    PlaybackChannelClient *playback_client = SPICE_CONTAINEROF(client, PlaybackChannelClient, base);
+    if (!playback_client->free_frames) {
         return;
     }
     spice_assert(client->active);
-- 
2.9.3