1 files changed, 166 insertions, 0 deletions
diff --git a/dom/media/MediaShutdownManager.cpp b/dom/media/MediaShutdownManager.cpp
new file mode 100644
index 000000000..089cd96a6
--- /dev/null
+++ b/dom/media/MediaShutdownManager.cpp
@@ -0,0 +1,166 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* 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/. */
+
+#include "mozilla/Logging.h"
+#include "mozilla/StaticPtr.h"
+#include "nsContentUtils.h"
+
+#include "MediaDecoder.h"
+#include "MediaShutdownManager.h"
+
+namespace mozilla {
+
+extern LazyLogModule gMediaDecoderLog;
+#define DECODER_LOG(type, msg) MOZ_LOG(gMediaDecoderLog, type, msg)
+
+NS_IMPL_ISUPPORTS(MediaShutdownManager, nsIAsyncShutdownBlocker)
+
+MediaShutdownManager::MediaShutdownManager()
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_COUNT_CTOR(MediaShutdownManager);
+}
+
+MediaShutdownManager::~MediaShutdownManager()
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_COUNT_DTOR(MediaShutdownManager);
+}
+
+// Note that we don't use ClearOnShutdown() on this StaticRefPtr, as that
+// may interfere with our shutdown listener.
+StaticRefPtr<MediaShutdownManager> MediaShutdownManager::sInstance;
+
+MediaShutdownManager&
+MediaShutdownManager::Instance()
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_DIAGNOSTIC_ASSERT(sInstance);
+  return *sInstance;
+}
+
+static nsCOMPtr<nsIAsyncShutdownClient>
+GetShutdownBarrier()
+{
+  nsCOMPtr<nsIAsyncShutdownService> svc = services::GetAsyncShutdown();
+  MOZ_RELEASE_ASSERT(svc);
+
+  nsCOMPtr<nsIAsyncShutdownClient> barrier;
+  nsresult rv = svc->GetProfileBeforeChange(getter_AddRefs(barrier));
+  if (!barrier) {
+    // We are probably in a content process. We need to do cleanup at
+    // XPCOM shutdown in leakchecking builds.
+    rv = svc->GetXpcomWillShutdown(getter_AddRefs(barrier));
+  }
+  MOZ_RELEASE_ASSERT(NS_SUCCEEDED(rv));
+  MOZ_RELEASE_ASSERT(barrier);
+  return barrier.forget();
+}
+
+void
+MediaShutdownManager::InitStatics()
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  static bool sInitDone = false;
+  if (sInitDone) {
+    return;
+  }
+
+  sInitDone = true;
+  sInstance = new MediaShutdownManager();
+
+  nsresult rv = GetShutdownBarrier()->AddBlocker(
+    sInstance, NS_LITERAL_STRING(__FILE__), __LINE__,
+    NS_LITERAL_STRING("MediaShutdownManager shutdown"));
+  if (NS_FAILED(rv)) {
+    MOZ_CRASH_UNSAFE_PRINTF("Failed to add shutdown blocker! rv=%x", uint32_t(rv));
+  }
+}
+
+void
+MediaShutdownManager::RemoveBlocker()
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(mIsDoingXPCOMShutDown);
+  MOZ_ASSERT(mDecoders.Count() == 0);
+  GetShutdownBarrier()->RemoveBlocker(this);
+  // Clear our singleton reference. This will probably delete
+  // this instance, so don't deref |this| clearing sInstance.
+  sInstance = nullptr;
+  DECODER_LOG(LogLevel::Debug, ("MediaShutdownManager::BlockShutdown() end."));
+}
+
+nsresult
+MediaShutdownManager::Register(MediaDecoder* aDecoder)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  if (mIsDoingXPCOMShutDown) {
+    return NS_ERROR_ABORT;
+  }
+  // Don't call Register() after you've Unregistered() all the decoders,
+  // that's not going to work.
+  MOZ_ASSERT(!mDecoders.Contains(aDecoder));
+  mDecoders.PutEntry(aDecoder);
+  MOZ_ASSERT(mDecoders.Contains(aDecoder));
+  MOZ_ASSERT(mDecoders.Count() > 0);
+  return NS_OK;
+}
+
+void
+MediaShutdownManager::Unregister(MediaDecoder* aDecoder)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  if (!mDecoders.Contains(aDecoder)) {
+    return;
+  }
+  mDecoders.RemoveEntry(aDecoder);
+  if (mIsDoingXPCOMShutDown && mDecoders.Count() == 0) {
+    RemoveBlocker();
+  }
+}
+
+NS_IMETHODIMP
+MediaShutdownManager::GetName(nsAString& aName)
+{
+  aName = NS_LITERAL_STRING("MediaShutdownManager: shutdown");
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+MediaShutdownManager::GetState(nsIPropertyBag**)
+{
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+MediaShutdownManager::BlockShutdown(nsIAsyncShutdownClient*)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(sInstance);
+
+  DECODER_LOG(LogLevel::Debug, ("MediaShutdownManager::BlockShutdown() start..."));
+
+  // Set this flag to ensure no Register() is allowed when Shutdown() begins.
+  mIsDoingXPCOMShutDown = true;
+
+  auto oldCount = mDecoders.Count();
+  if (oldCount == 0) {
+    RemoveBlocker();
+    return NS_OK;
+  }
+
+  // Iterate over the decoders and shut them down.
+  for (auto iter = mDecoders.Iter(); !iter.Done(); iter.Next()) {
+    iter.Get()->GetKey()->NotifyXPCOMShutdown();
+    // Check MediaDecoder::Shutdown doesn't call Unregister() synchronously in
+    // order not to corrupt our hashtable traversal.
+    MOZ_ASSERT(mDecoders.Count() == oldCount);
+  }
+
+  return NS_OK;
+}
+
+} // namespace mozilla