Remove view backend bridge association on connection drops

Arrange for calling ViewBackend::unregisterSurface() also when a Surface is destroyed. This is a no-op if the nested compositor had the chance to receive and handle a FdoIPC::UnregisterSurface message before the surface is destroyed; but allows undoing the bridge association when the Wayland client connection is closed beforehand. The destruction callback for the surface is guaranteed to always be called by libwayland, even on dropped connections, to allow cleaning up reagardless of the fate of its clients. Among others, this covers the case in which a WPEWebProcess is abruptly exited, for example due to a crash or a top-level resource load being blocked by a content filter. Co-authored-by: Adrian Perez de Castro <[email protected]> Acked-by: Adrian Perez de Castro <[email protected]> Signed-off-by: Pablo Saavedra <[email protected]> (cherry picked from commit 4e64c8d)
Igalia · May 12, 2021 · a01f2c0 · a01f2c0
1 parent 007a285
commit a01f2c0
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Showing 3 changed files with 16 additions and 1 deletion.
diff --git a/src/view-backend-private.h b/src/view-backend-private.h
@@ -68,6 +68,12 @@ class ViewBackend final : public WS::APIClient, public FdoIPC::MessageReceiver {
     void exportLinuxDmabuf(const struct linux_dmabuf_buffer *dmabuf_buffer) override;
     void exportShmBuffer(struct wl_resource* bufferResource, struct wl_shm_buffer* shmBuffer) override;
     void exportEGLStreamProducer(struct wl_resource*) override;
+
+    void bridgeConnectionLost(uint32_t id) override
+    {
+         unregisterSurface(id);
+    }
+
     void dispatchFrameCallbacks();
     void releaseBuffer(struct wl_resource* buffer_resource);
 

diff --git a/src/ws.cpp b/src/ws.cpp
@@ -545,8 +545,11 @@ void Instance::unregisterSurface(Surface* surface)
         [surface](const std::pair<uint32_t, Surface*>& value) -> bool {
             return value.second == surface;
         });
-    if (it != m_viewBackendMap.end())
+    if (it != m_viewBackendMap.end()) {
         m_viewBackendMap.erase(it);
+        if (surface->apiClient)
+            surface->apiClient->bridgeConnectionLost(it->first);
+    }
 }
 
 void Instance::dispatchFrameCallbacks(uint32_t bridgeId)

diff --git a/src/ws.h b/src/ws.h
@@ -45,6 +45,12 @@ struct APIClient {
     virtual void exportLinuxDmabuf(const struct linux_dmabuf_buffer *dmabuf_buffer) = 0;
     virtual void exportShmBuffer(struct wl_resource*, struct wl_shm_buffer*) = 0;
     virtual void exportEGLStreamProducer(struct wl_resource*) = 0;
+
+    // Invoked when the association with the surface associated with a given
+    // wpe_bridge identifier is no longer valid, typically due to the nested
+    // compositor client being disconnected before having the chance to read
+    // and process a FdoIPC::UnregisterSurface message.
+    virtual void bridgeConnectionLost(uint32_t bridgeId) = 0;
 };
 
 struct Surface {