tor-browser

MediaShutdownManager.cpp (6075B)

---

/* -*- 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 "MediaShutdownManager.h"

#include "MediaDecoder.h"
#include "mozilla/Logging.h"
#include "mozilla/Services.h"
#include "mozilla/StaticPtr.h"
#include "mozilla/media/MediaUtils.h"
#include "nsComponentManagerUtils.h"
#include "nsIWritablePropertyBag2.h"

namespace mozilla {

#undef LOGW

extern LazyLogModule gMediaDecoderLog;
#define DECODER_LOG(type, msg) MOZ_LOG(gMediaDecoderLog, type, msg)
#define LOGW(...) NS_WARNING(nsPrintfCString(__VA_ARGS__).get())

NS_IMPL_ISUPPORTS(MediaShutdownManager, nsIAsyncShutdownBlocker)

MediaShutdownManager::MediaShutdownManager() {
 MOZ_ASSERT(NS_IsMainThread());
 MOZ_DIAGNOSTIC_ASSERT(sInitPhase == NotInited);
}

MediaShutdownManager::~MediaShutdownManager() { MOZ_ASSERT(NS_IsMainThread()); }

// Note that we don't use ClearOnShutdown() on this StaticRefPtr, as that
// may interfere with our shutdown listener.
StaticRefPtr<MediaShutdownManager> MediaShutdownManager::sInstance;

MediaShutdownManager::InitPhase MediaShutdownManager::sInitPhase =
   MediaShutdownManager::NotInited;

MediaShutdownManager& MediaShutdownManager::Instance() {
 MOZ_ASSERT(NS_IsMainThread());
#ifdef MOZ_DIAGNOSTIC_ASSERT_ENABLED
 if (!sInstance) {
   MOZ_CRASH_UNSAFE_PRINTF("sInstance is null. sInitPhase=%d",
                           int(sInitPhase));
 }
#endif
 return *sInstance;
}

void MediaShutdownManager::InitStatics() {
 MOZ_ASSERT(NS_IsMainThread());
 if (sInitPhase != NotInited) {
   return;
 }

 sInstance = new MediaShutdownManager();
 MOZ_DIAGNOSTIC_ASSERT(sInstance);

 nsCOMPtr<nsIAsyncShutdownClient> barrier = media::GetShutdownBarrier();

 if (!barrier) {
   LOGW("Failed to get barrier, cannot add shutdown blocker!");
   sInitPhase = InitFailed;
   return;
 }

 nsresult rv =
     barrier->AddBlocker(sInstance, NS_LITERAL_STRING_FROM_CSTRING(__FILE__),
                         __LINE__, u"MediaShutdownManager shutdown"_ns);
 if (NS_FAILED(rv)) {
   LOGW("Failed to add shutdown blocker! rv=%x", uint32_t(rv));
   sInitPhase = InitFailed;
   return;
 }
 sInitPhase = InitSucceeded;
}

void MediaShutdownManager::RemoveBlocker() {
 MOZ_ASSERT(NS_IsMainThread());
 MOZ_DIAGNOSTIC_ASSERT(sInitPhase == XPCOMShutdownStarted);
 MOZ_ASSERT(mDecoders.Count() == 0);
 nsCOMPtr<nsIAsyncShutdownClient> barrier = media::GetShutdownBarrier();
 // xpcom should still be available because we blocked shutdown by having a
 // blocker. Until it completely shuts down we should still be able to get
 // the barrier.
 MOZ_RELEASE_ASSERT(
     barrier,
     "Failed to get shutdown barrier, cannot remove shutdown blocker!");
 barrier->RemoveBlocker(this);
 // Clear our singleton reference. This will probably delete
 // this instance, so don't deref |this| clearing sInstance.
 sInitPhase = XPCOMShutdownEnded;
 sInstance = nullptr;
 DECODER_LOG(LogLevel::Debug, ("MediaShutdownManager::BlockShutdown() end."));
}

nsresult MediaShutdownManager::Register(MediaDecoder* aDecoder) {
 MOZ_ASSERT(NS_IsMainThread());
 if (sInitPhase == InitFailed) {
   return NS_ERROR_NOT_INITIALIZED;
 }
 if (sInitPhase == XPCOMShutdownStarted) {
   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.Insert(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.EnsureRemoved(aDecoder)) {
   return;
 }
 if (sInitPhase == XPCOMShutdownStarted && mDecoders.Count() == 0) {
   RemoveBlocker();
 }
}

NS_IMETHODIMP
MediaShutdownManager::GetName(nsAString& aName) {
 aName = u"MediaShutdownManager: shutdown"_ns;
 return NS_OK;
}

NS_IMETHODIMP
MediaShutdownManager::GetState(nsIPropertyBag** aBagOut) {
 MOZ_ASSERT(NS_IsMainThread());
 MOZ_ASSERT(aBagOut);

 nsCOMPtr<nsIWritablePropertyBag2> propertyBag =
     do_CreateInstance("@mozilla.org/hash-property-bag;1");

 if (NS_WARN_IF(!propertyBag)) {
   return NS_ERROR_OUT_OF_MEMORY;
 }

 nsresult rv = propertyBag->SetPropertyAsInt32(
     u"sInitPhase"_ns, static_cast<int32_t>(sInitPhase));

 if (NS_WARN_IF(NS_FAILED(rv))) {
   return rv;
 }

 nsAutoCString decoderInfo;
 for (const auto& key : mDecoders) {
   // Grab the full extended type for the decoder. This can be used to help
   // indicate problems with specific decoders by associating type -> decoder.
   decoderInfo.Append(key->ContainerType().ExtendedType().OriginalString());
   decoderInfo.Append(", ");
 }

 rv = propertyBag->SetPropertyAsACString(u"decoderInfo"_ns, decoderInfo);

 if (NS_WARN_IF(NS_FAILED(rv))) {
   return rv;
 }

 propertyBag.forget(aBagOut);

 return NS_OK;
}

NS_IMETHODIMP
MediaShutdownManager::BlockShutdown(nsIAsyncShutdownClient*) {
 MOZ_ASSERT(NS_IsMainThread());
 MOZ_DIAGNOSTIC_ASSERT(sInitPhase == InitSucceeded);
 MOZ_DIAGNOSTIC_ASSERT(sInstance);

 DECODER_LOG(LogLevel::Debug,
             ("MediaShutdownManager::BlockShutdown() start..."));

 // Set this flag to ensure no Register() is allowed when Shutdown() begins.
 sInitPhase = XPCOMShutdownStarted;

 auto oldCount = mDecoders.Count();
 if (oldCount == 0) {
   RemoveBlocker();
   return NS_OK;
 }

 // Iterate over the decoders and shut them down.
 for (const auto& key : mDecoders) {
   key->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

// avoid redefined macro in unified build
#undef LOGW