[GStreamer] Prevent a crash when fetching data on stopped MediaRecorder

https://bugs.webkit.org/show_bug.cgi?id=260649 rdar://problem/114370120 Reviewed by Xabier Rodriguez-Calvar. The backend (GStreamer transcoder) is now clearly separated from the MediaRecorderPrivate, so that fetchData() can create a weak pointer to be used from the main thread. If the backend was destroyed in-flight no unsafe memory access is performed. Test: http/wpt/mediarecorder/MediaRecorder-start-stop-crash.html Canonical link: https://commits.webkit.org/267345@main
WebKit · Aug 28, 2023 · 37bc742 · 37bc742
1 parent 5b28d64
commit 37bc742
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Showing 5 changed files with 224 additions and 61 deletions.
diff --git a/LayoutTests/http/wpt/mediarecorder/MediaRecorder-start-stop-crash.html b/LayoutTests/http/wpt/mediarecorder/MediaRecorder-start-stop-crash.html
@@ -0,0 +1,20 @@
+<!doctype html>
+<html>
+<head>
+    <title>Starting and stopping a MediaRecorder should trigger no crash</title>
+    <script src="/resources/testharness.js"></script>
+    <script src="/resources/testharnessreport.js"></script>
+</head>
+<body>
+    <script>
+     promise_test(async (t) => {
+         const audioContext = new AudioContext();
+         const destination = audioContext.createMediaStreamDestination();
+         const recorder = new MediaRecorder(destination.stream);
+
+         recorder.start();
+         recorder.stop();
+     }, "Starting and stopping a MediaRecorder should trigger no crash");
+    </script>
+</body>
+</html>
diff --git a/Source/WebCore/platform/graphics/gstreamer/GRefPtrGStreamer.cpp b/Source/WebCore/platform/graphics/gstreamer/GRefPtrGStreamer.cpp
@@ -34,6 +34,10 @@
 #undef GST_USE_UNSTABLE_API
 #endif
 
+#if USE(GSTREAMER_TRANSCODER)
+#include <gst/transcoder/gsttranscoder.h>
+#endif
+
 namespace WTF {
 
 template<> GRefPtr<GstMiniObject> adoptGRef(GstMiniObject* ptr)
@@ -857,6 +861,54 @@ template<> void derefGPtr<GstWebRTCICE>(GstWebRTCICE* ptr)
 
 #endif // USE(GSTREAMER_WEBRTC)
 
+#if USE(GSTREAMER_TRANSCODER)
+
+template<>
+GRefPtr<GstTranscoder> adoptGRef(GstTranscoder* ptr)
+{
+    return GRefPtr<GstTranscoder>(ptr, GRefPtrAdopt);
+}
+
+template<>
+GstTranscoder* refGPtr<GstTranscoder>(GstTranscoder* ptr)
+{
+    if (ptr)
+        gst_object_ref(GST_OBJECT_CAST(ptr));
+
+    return ptr;
+}
+
+template<>
+void derefGPtr<GstTranscoder>(GstTranscoder* ptr)
+{
+    if (ptr)
+        gst_object_unref(ptr);
+}
+
+template<>
+GRefPtr<GstTranscoderSignalAdapter> adoptGRef(GstTranscoderSignalAdapter* ptr)
+{
+    return GRefPtr<GstTranscoderSignalAdapter>(ptr, GRefPtrAdopt);
+}
+
+template<>
+GstTranscoderSignalAdapter* refGPtr<GstTranscoderSignalAdapter>(GstTranscoderSignalAdapter* ptr)
+{
+    if (ptr)
+        g_object_ref(G_OBJECT(ptr));
+
+    return ptr;
+}
+
+template<>
+void derefGPtr<GstTranscoderSignalAdapter>(GstTranscoderSignalAdapter* ptr)
+{
+    if (ptr)
+        g_object_unref(ptr);
+}
+
+#endif // USE(GSTREAMER_TRANSCODER)
+
 } // namespace WTF
 
 #endif // USE(GSTREAMER)
diff --git a/Source/WebCore/platform/graphics/gstreamer/GRefPtrGStreamer.h b/Source/WebCore/platform/graphics/gstreamer/GRefPtrGStreamer.h
@@ -49,6 +49,11 @@ typedef struct _GstRTPHeaderExtension GstRTPHeaderExtension;
 typedef struct _GstWebRTCICE GstWebRTCICE;
 #endif
 
+#if USE(GSTREAMER_TRANSCODER)
+typedef struct _GstTranscoder GstTranscoder;
+typedef struct _GstTranscoderSignalAdapter GstTranscoderSignalAdapter;
+#endif
+
 namespace WTF {
 
 template<> GRefPtr<GstPlugin> adoptGRef(GstPlugin* ptr);
@@ -222,6 +227,16 @@ template<> void derefGPtr<GstWebRTCICE>(GstWebRTCICE*);
 
 #endif
 
+#if USE(GSTREAMER_TRANSCODER)
+template<> GRefPtr<GstTranscoder> adoptGRef(GstTranscoder*);
+template<> GstTranscoder* refGPtr<GstTranscoder>(GstTranscoder*);
+template<> void derefGPtr<GstTranscoder>(GstTranscoder*);
+
+template<> GRefPtr<GstTranscoderSignalAdapter> adoptGRef(GstTranscoderSignalAdapter*);
+template<> GstTranscoderSignalAdapter* refGPtr<GstTranscoderSignalAdapter>(GstTranscoderSignalAdapter*);
+template<> void derefGPtr<GstTranscoderSignalAdapter>(GstTranscoderSignalAdapter*);
+#endif // USE(GSTREAMER_TRANSCODER)
+
 } // namespace WTF
 
 #endif // USE(GSTREAMER)