[GStreamer] Misc leak fixes

https://bugs.webkit.org/show_bug.cgi?id=266188

Reviewed by Xabier Rodriguez-Calvar.

The GStreamer device-related objects were leaked, along with a couple GstStream objects in the
player. There are more issues, specially in the MSE code, but that's for another time...

We now explicitely clean-up the capture device managers and the registry scanner before
de-initializing GStreamer. The FastMalloc allocator is flagged as leaked as well, as it is static
and I didn't find how to properly clean it up.

* Source/WebCore/platform/graphics/gstreamer/GStreamerCommon.cpp:
(WebCore::deinitializeGStreamer):
* Source/WebCore/platform/graphics/gstreamer/GStreamerCommon.h:
* Source/WebCore/platform/graphics/gstreamer/GStreamerRegistryScanner.cpp:
(WebCore::teardownGStreamerRegistryScanner):
(WebCore::GStreamerRegistryScanner::ElementFactories::hasElementForCaps const):
(WebCore::GStreamerRegistryScanner::teardown):
* Source/WebCore/platform/graphics/gstreamer/GStreamerRegistryScanner.h:
* Source/WebCore/platform/graphics/gstreamer/GstAllocatorFastMalloc.cpp:
(gst_allocator_fast_malloc_init):
* Source/WebCore/platform/graphics/gstreamer/MediaPlayerPrivateGStreamer.cpp:
(WebCore::MediaPlayerPrivateGStreamer::handleMessage):
* Source/WebCore/platform/mediastream/gstreamer/GStreamerCaptureDeviceManager.cpp:
(WebCore::teardownGStreamerCaptureDeviceManagers):
(WebCore::GStreamerCaptureDeviceManager::~GStreamerCaptureDeviceManager):
(WebCore::GStreamerCaptureDeviceManager::teardown):
(WebCore::GStreamerCaptureDeviceManager::captureDevices):
(WebCore::GStreamerCaptureDeviceManager::refreshCaptureDevices):
* Source/WebCore/platform/mediastream/gstreamer/GStreamerCaptureDeviceManager.h:
* Source/WebKit/WebProcess/gtk/WebProcessMainGtk.cpp:
* Source/WebKit/WebProcess/wpe/WebProcessMainWPE.cpp:

Canonical link: https://commits.webkit.org/271861@main

Author: philn

Source/WebCore/platform/graphics/gstreamer/GstAllocatorFastMalloc.cpp

@@ -148,6 +148,8 @@ static void gst_allocator_fast_malloc_init(GstAllocatorFastMalloc* allocator)
 {
     auto* baseAllocator = GST_ALLOCATOR_CAST(allocator);
 
+    GST_OBJECT_FLAG_SET(allocator, GST_OBJECT_FLAG_MAY_BE_LEAKED);
+
     baseAllocator->mem_type = "FastMalloc";
     baseAllocator->mem_map = reinterpret_cast<GstMemoryMapFunction>(gstAllocatorFastMallocMemMap);
     baseAllocator->mem_unmap = reinterpret_cast<GstMemoryUnmapFunction>(gstAllocatorFastMallocMemUnmap);

Source/WebCore/platform/graphics/gstreamer/MediaPlayerPrivateGStreamer.cpp

@@ -2084,8 +2084,8 @@ void MediaPlayerPrivateGStreamer::handleMessage(GstMessage* message)
         GST_DEBUG_OBJECT(m_pipeline.get(), "Received STREAMS_SELECTED message selecting the following streams:");
         unsigned numStreams = gst_message_streams_selected_get_size(message);
         for (unsigned i = 0; i < numStreams; i++) {
-            GstStream* stream = gst_message_streams_selected_get_stream(message, i);
-            GST_DEBUG_OBJECT(pipeline(), "#%u %s %s", i, gst_stream_type_get_name(gst_stream_get_stream_type(stream)), gst_stream_get_stream_id(stream));
+            auto stream = adoptGRef(gst_message_streams_selected_get_stream(message, i));
+            GST_DEBUG_OBJECT(pipeline(), "#%u %s %s", i, gst_stream_type_get_name(gst_stream_get_stream_type(stream.get())), gst_stream_get_stream_id(stream.get()));
         }
 #endif
         GST_DEBUG_OBJECT(m_pipeline.get(), "Setting m_waitingForStreamsSelectedEvent to false.");

Source/WebCore/platform/mediastream/gstreamer/GStreamerCaptureDeviceManager.cpp

@@ -63,10 +63,39 @@ GStreamerVideoCaptureDeviceManager& GStreamerVideoCaptureDeviceManager::singleto
     return manager;
 }
 
+void teardownGStreamerCaptureDeviceManagers()
+{
+    auto& audioManager = GStreamerAudioCaptureDeviceManager::singleton();
+    audioManager.teardown();
+
+    auto& videoManager = GStreamerVideoCaptureDeviceManager::singleton();
+    videoManager.teardown();
+}
+
 GStreamerCaptureDeviceManager::~GStreamerCaptureDeviceManager()
 {
-    if (m_deviceMonitor)
-        gst_device_monitor_stop(m_deviceMonitor.get());
+    teardown();
+}
+
+void GStreamerCaptureDeviceManager::teardown()
+{
+    GST_DEBUG_OBJECT(m_deviceMonitor.get(), "Tearing down");
+    m_isTearingDown = true;
+    stopMonitor();
+    RealtimeMediaSourceCenter::singleton().removeDevicesChangedObserver(*this);
+    m_devices.clear();
+    m_gstreamerDevices.clear();
+}
+
+void GStreamerCaptureDeviceManager::stopMonitor()
+{
+    if (!m_deviceMonitor)
+        return;
+
+    auto bus = adoptGRef(gst_device_monitor_get_bus(m_deviceMonitor.get()));
+    gst_bus_remove_watch(bus.get());
+    gst_device_monitor_stop(m_deviceMonitor.get());
+    m_deviceMonitor.clear();
 }
 
 std::optional<GStreamerCaptureDevice> GStreamerCaptureDeviceManager::gstreamerDeviceWithUID(const String& deviceID)
@@ -87,7 +116,7 @@ const Vector<CaptureDevice>& GStreamerCaptureDeviceManager::captureDevices()
     std::call_once(onceFlag, [] {
         GST_DEBUG_CATEGORY_INIT(webkitGStreamerCaptureDeviceManagerDebugCategory, "webkitcapturedevicemanager", 0, "WebKit Capture Device Manager");
     });
-    if (m_devices.isEmpty())
+    if (m_devices.isEmpty() && !m_isTearingDown)
         refreshCaptureDevices();
 
     return m_devices;
@@ -129,7 +158,12 @@ void GStreamerCaptureDeviceManager::addDevice(GRefPtr<GstDevice>&& device)
 
 void GStreamerCaptureDeviceManager::refreshCaptureDevices()
 {
+    GST_DEBUG_OBJECT(m_deviceMonitor.get(), "Refreshing capture devices");
     m_devices.clear();
+    m_gstreamerDevices.clear();
+    if (m_isTearingDown)
+        return;
+
     if (!m_deviceMonitor) {
         m_deviceMonitor = adoptGRef(gst_device_monitor_new());
 

Source/WebCore/platform/mediastream/gstreamer/GStreamerCaptureDeviceManager.h

@@ -29,25 +29,34 @@
 #include "GStreamerVideoCapturer.h"
 #include "RealtimeMediaSourceFactory.h"
 
+#include <wtf/Noncopyable.h>
+
 namespace WebCore {
 
 using NodeAndFD = GStreamerVideoCapturer::NodeAndFD;
 
-class GStreamerCaptureDeviceManager : public CaptureDeviceManager {
+void teardownGStreamerCaptureDeviceManagers();
+
+class GStreamerCaptureDeviceManager : public CaptureDeviceManager
+WTF_MAKE_NONCOPYABLE(GStreamerCaptureDeviceManager)
+{
 public:
     ~GStreamerCaptureDeviceManager();
     std::optional<GStreamerCaptureDevice> gstreamerDeviceWithUID(const String&);
 
     const Vector<CaptureDevice>& captureDevices() final;
     virtual CaptureDevice::DeviceType deviceType() = 0;
 
+    void teardown();
+
 private:
     void addDevice(GRefPtr<GstDevice>&&);
     void refreshCaptureDevices();
 
     GRefPtr<GstDeviceMonitor> m_deviceMonitor;
     Vector<GStreamerCaptureDevice> m_gstreamerDevices;
     Vector<CaptureDevice> m_devices;
+    bool m_isTearingDown { false };
 };
 
 class GStreamerAudioCaptureDeviceManager final : public GStreamerCaptureDeviceManager {

Source/WebKit/WebProcess/gtk/WebProcessMainGtk.cpp

@@ -37,7 +37,7 @@
 #endif
 
 #if USE(GSTREAMER)
-#include <gst/gst.h>
+#include <WebCore/GStreamerCommon.h>
 #endif
 
 #if USE(GCRYPT)
@@ -75,7 +75,7 @@ class WebProcessMainGtk final: public AuxiliaryProcessMainBase<WebProcess> {
     void platformFinalize() override
     {
 #if USE(GSTREAMER)
-        gst_deinit();
+        deinitializeGStreamer();
 #endif
     }
 };

Source/WebKit/WebProcess/wpe/WebProcessMainWPE.cpp

@@ -36,7 +36,7 @@
 #endif
 
 #if USE(GSTREAMER)
-#include <gst/gst.h>
+#include <WebCore/GStreamerCommon.h>
 #endif
 
 namespace WebKit {
@@ -65,7 +65,7 @@ class WebProcessMainWPE final : public AuxiliaryProcessMainBase<WebProcess> {
     void platformFinalize() override
     {
 #if USE(GSTREAMER)
-        gst_deinit();
+        deinitializeGStreamer();
 #endif
     }
 };