[mutter/gnome-3-36] screen-cast/src: Make record functions return an error when failing

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 2d899596e21d43ab241d0ba37c0a9f90c2e610be
Author: Jonas Ådahl <jadahl gmail com>
Date:   Fri Jul 3 16:57:01 2020 +0200

    screen-cast/src: Make record functions return an error when failing
    
    Now that we don't use the record function to early out depending on
    implicit state (don't record pixels if only cursor moved for example),
    let it simply report an error when it fails, as we should no longer ever
    return without pixels if nothing failed.
    
    https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1351

 src/backends/meta-screen-cast-monitor-stream-src.c | 19 ++++++-------
 src/backends/meta-screen-cast-stream-src.c         | 32 ++++++++++++++--------
 src/backends/meta-screen-cast-stream-src.h         | 10 ++++---
 src/backends/meta-screen-cast-window-stream-src.c  | 16 +++++++----
 4 files changed, 45 insertions(+), 32 deletions(-)
---
diff --git a/src/backends/meta-screen-cast-monitor-stream-src.c 
b/src/backends/meta-screen-cast-monitor-stream-src.c
index 17aa7aeb4b..570f16b4ed 100644
--- a/src/backends/meta-screen-cast-monitor-stream-src.c
+++ b/src/backends/meta-screen-cast-monitor-stream-src.c
@@ -366,8 +366,9 @@ meta_screen_cast_monitor_stream_src_disable (MetaScreenCastStreamSrc *src)
 }
 
 static gboolean
-meta_screen_cast_monitor_stream_src_record_to_buffer (MetaScreenCastStreamSrc *src,
-                                                      uint8_t                 *data)
+meta_screen_cast_monitor_stream_src_record_to_buffer (MetaScreenCastStreamSrc  *src,
+                                                      uint8_t                  *data,
+                                                      GError                  **error)
 {
   MetaScreenCastMonitorStreamSrc *monitor_src =
     META_SCREEN_CAST_MONITOR_STREAM_SRC (src);
@@ -384,8 +385,9 @@ meta_screen_cast_monitor_stream_src_record_to_buffer (MetaScreenCastStreamSrc *s
 }
 
 static gboolean
-meta_screen_cast_monitor_stream_src_record_to_framebuffer (MetaScreenCastStreamSrc *src,
-                                                           CoglFramebuffer         *framebuffer)
+meta_screen_cast_monitor_stream_src_record_to_framebuffer (MetaScreenCastStreamSrc  *src,
+                                                           CoglFramebuffer          *framebuffer,
+                                                           GError                  **error)
 {
   MetaScreenCastMonitorStreamSrc *monitor_src =
     META_SCREEN_CAST_MONITOR_STREAM_SRC (src);
@@ -409,7 +411,6 @@ meta_screen_cast_monitor_stream_src_record_to_framebuffer (MetaScreenCastStreamS
   for (l = meta_renderer_get_views (renderer); l; l = l->next)
     {
       ClutterStageView *view = CLUTTER_STAGE_VIEW (l->data);
-      g_autoptr (GError) error = NULL;
       CoglFramebuffer *view_framebuffer;
       MetaRectangle view_layout;
       int x, y;
@@ -430,12 +431,8 @@ meta_screen_cast_monitor_stream_src_record_to_framebuffer (MetaScreenCastStreamS
                                   x, y,
                                   cogl_framebuffer_get_width (view_framebuffer),
                                   cogl_framebuffer_get_height (view_framebuffer),
-                                  &error))
-        {
-          g_warning ("Error blitting view into DMABuf framebuffer: %s",
-                     error->message);
-          return FALSE;
-        }
+                                  error))
+        return FALSE;
     }
 
   cogl_framebuffer_finish (framebuffer);
diff --git a/src/backends/meta-screen-cast-stream-src.c b/src/backends/meta-screen-cast-stream-src.c
index 463d316ebe..4b79119571 100644
--- a/src/backends/meta-screen-cast-stream-src.c
+++ b/src/backends/meta-screen-cast-stream-src.c
@@ -135,23 +135,25 @@ meta_screen_cast_stream_src_get_videocrop (MetaScreenCastStreamSrc *src,
 }
 
 static gboolean
-meta_screen_cast_stream_src_record_to_buffer (MetaScreenCastStreamSrc *src,
-                                              uint8_t                 *data)
+meta_screen_cast_stream_src_record_to_buffer (MetaScreenCastStreamSrc  *src,
+                                              uint8_t                  *data,
+                                              GError                  **error)
 {
   MetaScreenCastStreamSrcClass *klass =
     META_SCREEN_CAST_STREAM_SRC_GET_CLASS (src);
 
-  return klass->record_to_buffer (src, data);
+  return klass->record_to_buffer (src, data, error);
 }
 
 static gboolean
-meta_screen_cast_stream_src_record_to_framebuffer (MetaScreenCastStreamSrc *src,
-                                                   CoglFramebuffer         *framebuffer)
+meta_screen_cast_stream_src_record_to_framebuffer (MetaScreenCastStreamSrc  *src,
+                                                   CoglFramebuffer          *framebuffer,
+                                                   GError                  **error)
 {
   MetaScreenCastStreamSrcClass *klass =
     META_SCREEN_CAST_STREAM_SRC_GET_CLASS (src);
 
-  return klass->record_to_framebuffer (src, framebuffer);
+  return klass->record_to_framebuffer (src, framebuffer, error);
 }
 
 static void
@@ -409,9 +411,10 @@ maybe_record_cursor (MetaScreenCastStreamSrc *src,
 }
 
 static gboolean
-do_record_frame (MetaScreenCastStreamSrc *src,
-                 struct spa_buffer       *spa_buffer,
-                 uint8_t                 *data)
+do_record_frame (MetaScreenCastStreamSrc  *src,
+                 struct spa_buffer        *spa_buffer,
+                 uint8_t                  *data,
+                 GError                  **error)
 {
   MetaScreenCastStreamSrcPrivate *priv =
     meta_screen_cast_stream_src_get_instance_private (src);
@@ -419,7 +422,7 @@ do_record_frame (MetaScreenCastStreamSrc *src,
   if (spa_buffer->datas[0].data ||
       spa_buffer->datas[0].type == SPA_DATA_MemFd)
     {
-      return meta_screen_cast_stream_src_record_to_buffer (src, data);
+      return meta_screen_cast_stream_src_record_to_buffer (src, data, error);
     }
   else if (spa_buffer->datas[0].type == SPA_DATA_DmaBuf)
     {
@@ -430,9 +433,12 @@ do_record_frame (MetaScreenCastStreamSrc *src,
         cogl_dma_buf_handle_get_framebuffer (dmabuf_handle);
 
       return meta_screen_cast_stream_src_record_to_framebuffer (src,
-                                                                dmabuf_fbo);
+                                                                dmabuf_fbo,
+                                                                error);
     }
 
+  g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
+               "Unknown SPA buffer type %u", spa_buffer->datas[0].type);
   return FALSE;
 }
 
@@ -447,6 +453,7 @@ meta_screen_cast_stream_src_maybe_record_frame (MetaScreenCastStreamSrc  *src,
   struct spa_buffer *spa_buffer;
   uint8_t *data = NULL;
   uint64_t now_us;
+  g_autoptr (GError) error = NULL;
 
   now_us = g_get_monotonic_time ();
   if (priv->video_format.max_framerate.num > 0 &&
@@ -474,7 +481,7 @@ meta_screen_cast_stream_src_maybe_record_frame (MetaScreenCastStreamSrc  *src,
 
   if (!(flags & META_SCREEN_CAST_RECORD_FLAG_CURSOR_ONLY))
     {
-      if (do_record_frame (src, spa_buffer, data))
+      if (do_record_frame (src, spa_buffer, data, &error))
         {
           struct spa_meta_region *spa_meta_video_crop;
 
@@ -505,6 +512,7 @@ meta_screen_cast_stream_src_maybe_record_frame (MetaScreenCastStreamSrc  *src,
         }
       else
         {
+          g_warning ("Failed to record screen cast frame: %s", error->message);
           spa_buffer->datas[0].chunk->size = 0;
         }
     }
diff --git a/src/backends/meta-screen-cast-stream-src.h b/src/backends/meta-screen-cast-stream-src.h
index 87054eedf5..152790ecfb 100644
--- a/src/backends/meta-screen-cast-stream-src.h
+++ b/src/backends/meta-screen-cast-stream-src.h
@@ -59,10 +59,12 @@ struct _MetaScreenCastStreamSrcClass
                       float                   *frame_rate);
   void (* enable) (MetaScreenCastStreamSrc *src);
   void (* disable) (MetaScreenCastStreamSrc *src);
-  gboolean (* record_to_buffer) (MetaScreenCastStreamSrc *src,
-                                 uint8_t                 *data);
-  gboolean (* record_to_framebuffer) (MetaScreenCastStreamSrc *src,
-                                      CoglFramebuffer         *framebuffer);
+  gboolean (* record_to_buffer) (MetaScreenCastStreamSrc  *src,
+                                 uint8_t                  *data,
+                                 GError                  **error);
+  gboolean (* record_to_framebuffer) (MetaScreenCastStreamSrc  *src,
+                                      CoglFramebuffer          *framebuffer,
+                                      GError                  **error);
   gboolean (* get_videocrop) (MetaScreenCastStreamSrc *src,
                               MetaRectangle           *crop_rect);
   void (* set_cursor_metadata) (MetaScreenCastStreamSrc *src,
diff --git a/src/backends/meta-screen-cast-window-stream-src.c 
b/src/backends/meta-screen-cast-window-stream-src.c
index dfc5baa1a2..a504bd1949 100644
--- a/src/backends/meta-screen-cast-window-stream-src.c
+++ b/src/backends/meta-screen-cast-window-stream-src.c
@@ -457,8 +457,9 @@ meta_screen_cast_window_stream_src_disable (MetaScreenCastStreamSrc *src)
 }
 
 static gboolean
-meta_screen_cast_window_stream_src_record_to_buffer (MetaScreenCastStreamSrc *src,
-                                                     uint8_t                 *data)
+meta_screen_cast_window_stream_src_record_to_buffer (MetaScreenCastStreamSrc  *src,
+                                                     uint8_t                  *data,
+                                                     GError                  **error)
 {
   MetaScreenCastWindowStreamSrc *window_src =
     META_SCREEN_CAST_WINDOW_STREAM_SRC (src);
@@ -469,8 +470,9 @@ meta_screen_cast_window_stream_src_record_to_buffer (MetaScreenCastStreamSrc *sr
 }
 
 static gboolean
-meta_screen_cast_window_stream_src_record_to_framebuffer (MetaScreenCastStreamSrc *src,
-                                                          CoglFramebuffer         *framebuffer)
+meta_screen_cast_window_stream_src_record_to_framebuffer (MetaScreenCastStreamSrc  *src,
+                                                          CoglFramebuffer          *framebuffer,
+                                                          GError                  **error)
 {
   MetaScreenCastWindowStreamSrc *window_src =
     META_SCREEN_CAST_WINDOW_STREAM_SRC (src);
@@ -485,7 +487,11 @@ meta_screen_cast_window_stream_src_record_to_framebuffer (MetaScreenCastStreamSr
   if (!meta_screen_cast_window_blit_to_framebuffer (window_src->screen_cast_window,
                                                     &stream_rect,
                                                     framebuffer))
-    return FALSE;
+    {
+      g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
+                   "Failed to blit window content to framebuffer");
+      return FALSE;
+    }
 
   stream = meta_screen_cast_stream_src_get_stream (src);
   switch (meta_screen_cast_stream_get_cursor_mode (stream))