gecko-dev/dom/media/MediaShutdownManager.cpp

162 lines
4.8 KiB
C++

/* -*- 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()
: mIsObservingShutdown(false)
, mIsDoingXPCOMShutDown(false)
{
MOZ_ASSERT(NS_IsMainThread());
}
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&
MediaShutdownManager::Instance()
{
MOZ_ASSERT(NS_IsMainThread());
if (!sInstance) {
sInstance = new MediaShutdownManager();
}
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::EnsureCorrectShutdownObserverState()
{
bool needShutdownObserver = mDecoders.Count() > 0;
if (needShutdownObserver != mIsObservingShutdown) {
mIsObservingShutdown = needShutdownObserver;
if (mIsObservingShutdown) {
nsresult rv = GetShutdownBarrier()->AddBlocker(
this, NS_LITERAL_STRING(__FILE__), __LINE__,
NS_LITERAL_STRING("MediaShutdownManager shutdown"));
if (NS_FAILED(rv)) {
// Leak the buffer on the heap to make sure that it lives long enough,
// as MOZ_CRASH_ANNOTATE expects the pointer passed to it to live to
// the end of the program.
const size_t CAPACITY = 256;
auto buf = new char[CAPACITY];
snprintf(buf, CAPACITY, "Failed to add shutdown blocker! rv=%x", uint32_t(rv));
MOZ_CRASH_ANNOTATE(buf);
MOZ_REALLY_CRASH();
}
} else {
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."));
}
}
}
void
MediaShutdownManager::Register(MediaDecoder* aDecoder)
{
MOZ_ASSERT(NS_IsMainThread());
MOZ_RELEASE_ASSERT(!mIsDoingXPCOMShutDown);
// 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);
EnsureCorrectShutdownObserverState();
}
void
MediaShutdownManager::Unregister(MediaDecoder* aDecoder)
{
MOZ_ASSERT(NS_IsMainThread());
MOZ_ASSERT(mDecoders.Contains(aDecoder));
mDecoders.RemoveEntry(aDecoder);
EnsureCorrectShutdownObserverState();
}
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;
DebugOnly<uint32_t> oldCount = mDecoders.Count();
MOZ_ASSERT(oldCount > 0);
// Iterate over the decoders and shut them down.
for (auto iter = mDecoders.Iter(); !iter.Done(); iter.Next()) {
MediaDecoderOwner* owner = iter.Get()->GetKey()->GetOwner();
if (owner) {
// The owner will call MediaDecoder::Shutdown() and
// drop its reference to the decoder.
owner->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