plugins: Check return values of gst_buffer_map()

They can fail for various reasons.

For non-fatal cases (such as the dump feature of identiy and fakesink),
we just silently skip it.

For other cases post an error message.

https://bugzilla.gnome.org/show_bug.cgi?id=728326

plugins/elements/gstfakesink.c

@@ -479,9 +479,10 @@ gst_fake_sink_render (GstBaseSink * bsink, GstBuffer * buf)
   if (sink->dump) {
     GstMapInfo info;
 
-    gst_buffer_map (buf, &info, GST_MAP_READ);
+    if (gst_buffer_map (buf, &info, GST_MAP_READ)) {
-    gst_util_dump_mem (info.data, info.size);
+      gst_util_dump_mem (info.data, info.size);
-    gst_buffer_unmap (buf, &info);
+      gst_buffer_unmap (buf, &info);
+    }
   }
   if (sink->num_buffers_left == 0)
     goto eos;

plugins/elements/gstfakesrc.c

@@ -716,7 +716,10 @@ gst_fake_src_create_buffer (GstFakeSrc * src, gsize * bufsize)
         /* try again (this will allocate a new parent) */
         return gst_fake_src_create_buffer (src, bufsize);
       }
-      gst_buffer_map (buf, &info, GST_MAP_WRITE);
+      if (buf == NULL)
+        goto buffer_create_fail;
+      if (!gst_buffer_map (buf, &info, GST_MAP_WRITE))
+        goto buffer_write_fail;
       gst_fake_src_prepare_buffer (src, info.data, info.size);
       gst_buffer_unmap (buf, &info);
       break;
@@ -726,12 +729,28 @@ gst_fake_src_create_buffer (GstFakeSrc * src, gsize * bufsize)
       break;
   }
   if (dump) {
-    gst_buffer_map (buf, &info, GST_MAP_READ);
+    if (gst_buffer_map (buf, &info, GST_MAP_READ)) {
-    gst_util_dump_mem (info.data, info.size);
+      gst_util_dump_mem (info.data, info.size);
-    gst_buffer_unmap (buf, &info);
+      gst_buffer_unmap (buf, &info);
+    }
   }
 
   return buf;
+
+buffer_create_fail:
+  {
+    GST_ELEMENT_ERROR (src, RESOURCE, BUSY, (NULL),
+        ("Failed to create a buffer"));
+    return NULL;
+  }
+
+buffer_write_fail:
+  {
+    GST_ELEMENT_ERROR (src, RESOURCE, WRITE, (NULL),
+        ("Failed to write to buffer"));
+    gst_buffer_unref (buf);
+    return NULL;
+  }
 }
 
 static void

plugins/elements/gstfdsrc.c

@@ -446,7 +446,8 @@ gst_fd_src_create (GstPushSrc * psrc, GstBuffer ** outbuf)
   if (G_UNLIKELY (buf == NULL))
     goto alloc_failed;
 
-  gst_buffer_map (buf, &info, GST_MAP_WRITE);
+  if (!gst_buffer_map (buf, &info, GST_MAP_WRITE))
+    goto buffer_read_error;
 
   do {
     readbytes = read (src->fd, info.data, blocksize);
@@ -508,6 +509,12 @@ read_error:
     gst_buffer_unref (buf);
     return GST_FLOW_ERROR;
   }
+buffer_read_error:
+  {
+    GST_ELEMENT_ERROR (src, RESOURCE, WRITE, (NULL), ("Can't write to buffer"));
+    gst_buffer_unref (buf);
+    return GST_FLOW_ERROR;
+  }
 }
 
 static gboolean

plugins/elements/gstfilesrc.c

@@ -350,7 +350,8 @@ gst_file_src_fill (GstBaseSrc * basesrc, guint64 offset, guint length,
     src->read_position = offset;
   }
 
-  gst_buffer_map (buf, &info, GST_MAP_WRITE);
+  if (!gst_buffer_map (buf, &info, GST_MAP_WRITE))
+    goto buffer_write_fail;
   data = info.data;
 
   bytes_read = 0;
@@ -409,6 +410,11 @@ eos:
     gst_buffer_resize (buf, 0, 0);
     return GST_FLOW_EOS;
   }
+buffer_write_fail:
+  {
+    GST_ELEMENT_ERROR (src, RESOURCE, WRITE, (NULL), ("Can't write to buffer"));
+    return GST_FLOW_ERROR;
+  }
 }
 
 static gboolean

plugins/elements/gstidentity.c

@@ -603,9 +603,10 @@ gst_identity_transform_ip (GstBaseTransform * trans, GstBuffer * buf)
   if (identity->dump) {
     GstMapInfo info;
 
-    gst_buffer_map (buf, &info, GST_MAP_READ);
+    if (gst_buffer_map (buf, &info, GST_MAP_READ)) {
-    gst_util_dump_mem (info.data, info.size);
+      gst_util_dump_mem (info.data, info.size);
-    gst_buffer_unmap (buf, &info);
+      gst_buffer_unmap (buf, &info);
+    }
   }
 
   if (!identity->silent) {

plugins/elements/gstqueue2.c

@@ -1382,7 +1382,8 @@ gst_queue2_create_read (GstQueue2 * queue, guint64 offset, guint length,
   else
     buf = *buffer;
 
-  gst_buffer_map (buf, &info, GST_MAP_WRITE);
+  if (!gst_buffer_map (buf, &info, GST_MAP_WRITE))
+    goto buffer_write_fail;
   data = info.data;
 
   GST_DEBUG_OBJECT (queue, "Reading %u bytes from %" G_GUINT64_FORMAT, length,
@@ -1533,6 +1534,14 @@ read_error:
       gst_buffer_unref (buf);
     return ret;
   }
+buffer_write_fail:
+  {
+    GST_ELEMENT_ERROR (queue, RESOURCE, WRITE, (NULL),
+        ("Can't write to buffer"));
+    if (*buffer == NULL)
+      gst_buffer_unref (buf);
+    return GST_FLOW_ERROR;
+  }
 }
 
 /* should be called with QUEUE_LOCK */
@@ -1784,7 +1793,8 @@ gst_queue2_create_write (GstQueue2 * queue, GstBuffer * buffer)
   ring_buffer = queue->ring_buffer;
   rb_size = queue->ring_buffer_max_size;
 
-  gst_buffer_map (buffer, &info, GST_MAP_READ);
+  if (!gst_buffer_map (buffer, &info, GST_MAP_READ))
+    goto buffer_read_error;
 
   size = info.size;
   data = info.data;
@@ -2060,6 +2070,12 @@ handle_error:
     gst_buffer_unmap (buffer, &info);
     return FALSE;
   }
+buffer_read_error:
+  {
+    GST_ELEMENT_ERROR (queue, RESOURCE, READ, (NULL),
+        ("Can't read from buffer"));
+    return FALSE;
+  }
 }
 
 static gboolean