1 files changed, 164 insertions, 0 deletions
diff --git a/dom/media/gmp/GMPServiceChild.h b/dom/media/gmp/GMPServiceChild.h
new file mode 100644
index 0000000000..2775a83489
--- /dev/null
+++ b/dom/media/gmp/GMPServiceChild.h
@@ -0,0 +1,164 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef GMPServiceChild_h_
+#define GMPServiceChild_h_
+
+#include "GMPService.h"
+#include "MediaResult.h"
+#include "base/process.h"
+#include "mozilla/dom/PContent.h"
+#include "mozilla/gmp/PGMPServiceChild.h"
+#include "mozilla/MozPromise.h"
+#include "nsIAsyncShutdown.h"
+#include "nsRefPtrHashtable.h"
+
+namespace mozilla::gmp {
+
+class GMPContentParent;
+class GMPServiceChild;
+
+class GeckoMediaPluginServiceChild : public GeckoMediaPluginService,
+                                     public nsIAsyncShutdownBlocker {
+  friend class GMPServiceChild;
+
+ public:
+  static already_AddRefed<GeckoMediaPluginServiceChild> GetSingleton();
+  nsresult Init() override;
+
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_NSIASYNCSHUTDOWNBLOCKER
+
+  NS_IMETHOD HasPluginForAPI(const nsACString& aAPI,
+                             const nsTArray<nsCString>& aTags,
+                             bool* aRetVal) override;
+  NS_IMETHOD GetNodeId(const nsAString& aOrigin,
+                       const nsAString& aTopLevelOrigin,
+                       const nsAString& aGMPName,
+                       UniquePtr<GetNodeIdCallback>&& aCallback) override;
+
+  NS_DECL_NSIOBSERVER
+
+  void SetServiceChild(RefPtr<GMPServiceChild>&& aServiceChild);
+
+  void RemoveGMPContentParent(GMPContentParent* aGMPContentParent);
+
+  static void UpdateGMPCapabilities(
+      nsTArray<mozilla::dom::GMPCapabilityData>&& aCapabilities);
+
+  void BeginShutdown();
+
+ protected:
+  void InitializePlugins(nsISerialEventTarget*) override {
+    // Nothing to do here.
+  }
+
+  RefPtr<GetGMPContentParentPromise> GetContentParent(
+      GMPCrashHelper* aHelper, const NodeIdVariant& aNodeIdVariant,
+      const nsACString& aAPI, const nsTArray<nsCString>& aTags) override;
+
+ private:
+  friend class OpenPGMPServiceChild;
+
+  ~GeckoMediaPluginServiceChild() override;
+
+  typedef MozPromise<GMPServiceChild*, MediaResult, /* IsExclusive = */ true>
+      GetServiceChildPromise;
+  RefPtr<GetServiceChildPromise> GetServiceChild();
+
+  nsTArray<MozPromiseHolder<GetServiceChildPromise>> mGetServiceChildPromises;
+  RefPtr<GMPServiceChild> mServiceChild;
+
+  // Shutdown blocker management. A shutdown blocker is used to ensure that
+  // we do not shutdown until all content parents are removed from
+  // GMPServiceChild::mContentParents.
+  //
+  // The following rules let us shutdown block (and thus we shouldn't
+  // violate them):
+  // - We will only call GetContentParent if mShuttingDownOnGMPThread is false.
+  // - mShuttingDownOnGMPThread will become true once profile teardown is
+  //   observed in the parent process (and once GMPServiceChild receives a
+  //   message from GMPServiceParent) or if we block shutdown (which implies
+  //   we're in shutdown).
+  // - If we currently have mPendingGetContentParents > 0 or parents in
+  //   GMPServiceChild::mContentParents we should block shutdown so such
+  //   parents can be cleanly shutdown.
+  // therefore
+  // - We can block shutdown at xpcom-will-shutdown until our content parents
+  //   are handled.
+  // - Because once mShuttingDownOnGMPThread is true we cannot add new content
+  //   parents, we know that when mShuttingDownOnGMPThread && all content
+  //   parents are handled we'll never add more and it's safe to stop blocking
+  //   shutdown.
+  // this relies on
+  // - Once we're shutting down, we need to ensure all content parents are
+  //   shutdown and removed. Failure to do so will result in a shutdown stall.
+
+  // Note that at the time of writing there are significant differences in how
+  // xpcom shutdown is handled in release and non-release builds. For example,
+  // in release builds content processes are exited early, so xpcom shutdown
+  // is not observed (and not blocked by blockers). This is important to keep
+  // in mind when testing the shutdown blocking machinery (you won't see most
+  // of it be invoked in release).
+
+  // All of these members should only be used on the GMP thread unless
+  // otherwise noted!
+
+  // Add a shutdown blocker. Main thread only. Should only be called once when
+  // we init the service.
+  nsresult AddShutdownBlocker();
+  // Remove a shutdown blocker. Should be called once at most and only when
+  // mShuttingDownOnGMPThread. Prefer RemoveShutdownBlockerIfNeeded unless
+  // absolutely certain you need to call this directly.
+  void RemoveShutdownBlocker();
+  // Remove shutdown blocker if the following conditions are met:
+  // - mShuttingDownOnGMPThread.
+  // - !mServiceChild->HaveContentParents.
+  // - mPendingGetContentParents == 0.
+  // - mShutdownBlockerHasBeenAdded.
+  void RemoveShutdownBlockerIfNeeded();
+
+#ifdef DEBUG
+  // Track if we've added a shutdown blocker for sanity checking. Main thread
+  // only.
+  bool mShutdownBlockerAdded = false;
+#endif  // DEBUG
+  // The number of GetContentParent calls that have not yet been resolved or
+  // rejected. We use this value to help determine if we need to block
+  // shutdown. Should only be used on GMP thread to avoid races.
+  uint32_t mPendingGetContentParents = 0;
+  // End shutdown blocker management.
+};
+
+class GMPServiceChild : public PGMPServiceChild {
+ public:
+  // Mark AddRef and Release as `final`, as they overload pure virtual
+  // implementations in PGMPServiceChild.
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(GMPServiceChild, final)
+
+  explicit GMPServiceChild() = default;
+
+  already_AddRefed<GMPContentParent> GetBridgedGMPContentParent(
+      ProcessId aOtherPid, ipc::Endpoint<PGMPContentParent>&& endpoint);
+
+  void RemoveGMPContentParent(GMPContentParent* aGMPContentParent);
+
+  void GetAlreadyBridgedTo(nsTArray<ProcessId>& aAlreadyBridgedTo);
+
+  static bool Create(Endpoint<PGMPServiceChild>&& aGMPService);
+
+  ipc::IPCResult RecvBeginShutdown() override;
+
+  bool HaveContentParents() const;
+
+ private:
+  ~GMPServiceChild() = default;
+
+  nsRefPtrHashtable<nsUint64HashKey, GMPContentParent> mContentParents;
+};
+
+}  // namespace mozilla::gmp
+
+#endif  // GMPServiceChild_h_