gecko-dev/xpcom/base/CycleCollectedJSContext.h
2017-04-27 15:34:46 -07:00

245 lines
7.2 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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 mozilla_CycleCollectedJSContext_h
#define mozilla_CycleCollectedJSContext_h
#include <queue>
#include "mozilla/DeferredFinalize.h"
#include "mozilla/LinkedList.h"
#include "mozilla/mozalloc.h"
#include "mozilla/MemoryReporting.h"
#include "jsapi.h"
#include "jsfriendapi.h"
#include "nsCOMPtr.h"
#include "nsCycleCollectionParticipant.h"
#include "nsTArray.h"
class nsCycleCollectionNoteRootCallback;
class nsIException;
class nsIRunnable;
class nsThread;
class nsWrapperCache;
namespace mozilla {
class CycleCollectedJSRuntime;
// Contains various stats about the cycle collection.
struct CycleCollectorResults
{
CycleCollectorResults()
{
// Initialize here so when we increment mNumSlices the first time we're
// not using uninitialized memory.
Init();
}
void Init()
{
mForcedGC = false;
mMergedZones = false;
mAnyManual = false;
mVisitedRefCounted = 0;
mVisitedGCed = 0;
mFreedRefCounted = 0;
mFreedGCed = 0;
mFreedJSZones = 0;
mNumSlices = 1;
// mNumSlices is initialized to one, because we call Init() after the
// per-slice increment of mNumSlices has already occurred.
}
bool mForcedGC;
bool mMergedZones;
bool mAnyManual; // true if any slice of the CC was manually triggered, or at shutdown.
uint32_t mVisitedRefCounted;
uint32_t mVisitedGCed;
uint32_t mFreedRefCounted;
uint32_t mFreedGCed;
uint32_t mFreedJSZones;
uint32_t mNumSlices;
};
class CycleCollectedJSContext
: public LinkedListElement<CycleCollectedJSContext>
{
friend class CycleCollectedJSRuntime;
protected:
CycleCollectedJSContext();
virtual ~CycleCollectedJSContext();
MOZ_IS_CLASS_INIT
nsresult Initialize(JSRuntime* aParentRuntime,
uint32_t aMaxBytes,
uint32_t aMaxNurseryBytes);
// See explanation in mIsPrimaryContext.
MOZ_IS_CLASS_INIT
nsresult InitializeNonPrimary(CycleCollectedJSContext* aPrimaryContext);
virtual CycleCollectedJSRuntime* CreateRuntime(JSContext* aCx) = 0;
size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
std::queue<nsCOMPtr<nsIRunnable>> mPromiseMicroTaskQueue;
std::queue<nsCOMPtr<nsIRunnable>> mDebuggerPromiseMicroTaskQueue;
private:
MOZ_IS_CLASS_INIT
void InitializeCommon();
static JSObject* GetIncumbentGlobalCallback(JSContext* aCx);
static bool EnqueuePromiseJobCallback(JSContext* aCx,
JS::HandleObject aJob,
JS::HandleObject aAllocationSite,
JS::HandleObject aIncumbentGlobal,
void* aData);
static void PromiseRejectionTrackerCallback(JSContext* aCx,
JS::HandleObject aPromise,
PromiseRejectionHandlingState state,
void* aData);
void AfterProcessMicrotask(uint32_t aRecursionDepth);
public:
void ProcessStableStateQueue();
private:
void ProcessMetastableStateQueue(uint32_t aRecursionDepth);
public:
enum DeferredFinalizeType {
FinalizeIncrementally,
FinalizeNow,
};
CycleCollectedJSRuntime* Runtime() const
{
MOZ_ASSERT(mRuntime);
return mRuntime;
}
already_AddRefed<nsIException> GetPendingException() const;
void SetPendingException(nsIException* aException);
std::queue<nsCOMPtr<nsIRunnable>>& GetPromiseMicroTaskQueue();
std::queue<nsCOMPtr<nsIRunnable>>& GetDebuggerPromiseMicroTaskQueue();
JSContext* Context() const
{
MOZ_ASSERT(mJSContext);
return mJSContext;
}
JS::RootingContext* RootingCx() const
{
MOZ_ASSERT(mJSContext);
return JS::RootingContext::get(mJSContext);
}
bool MicroTaskCheckpointDisabled() const
{
return mDisableMicroTaskCheckpoint;
}
void DisableMicroTaskCheckpoint(bool aDisable)
{
mDisableMicroTaskCheckpoint = aDisable;
}
class MOZ_RAII AutoDisableMicroTaskCheckpoint
{
public:
AutoDisableMicroTaskCheckpoint()
: mCCJSCX(CycleCollectedJSContext::Get())
{
mOldValue = mCCJSCX->MicroTaskCheckpointDisabled();
mCCJSCX->DisableMicroTaskCheckpoint(true);
}
~AutoDisableMicroTaskCheckpoint()
{
mCCJSCX->DisableMicroTaskCheckpoint(mOldValue);
}
CycleCollectedJSContext* mCCJSCX;
bool mOldValue;
};
protected:
JSContext* MaybeContext() const { return mJSContext; }
public:
// nsThread entrypoints
virtual void BeforeProcessTask(bool aMightBlock) { };
virtual void AfterProcessTask(uint32_t aRecursionDepth);
// microtask processor entry point
void AfterProcessMicrotask();
uint32_t RecursionDepth();
// Run in stable state (call through nsContentUtils)
void RunInStableState(already_AddRefed<nsIRunnable>&& aRunnable);
// This isn't in the spec at all yet, but this gets the behavior we want for IDB.
// Runs after the current microtask completes.
void RunInMetastableState(already_AddRefed<nsIRunnable>&& aRunnable);
// Get the current thread's CycleCollectedJSContext. Returns null if there
// isn't one.
static CycleCollectedJSContext* Get();
// Queue an async microtask to the current main or worker thread.
virtual void DispatchToMicroTask(already_AddRefed<nsIRunnable> aRunnable);
// Storage for watching rejected promises waiting for some client to
// consume their rejection.
// Promises in this list have been rejected in the last turn of the
// event loop without the rejection being handled.
// Note that this can contain nullptrs in place of promises removed because
// they're consumed before it'd be reported.
JS::PersistentRooted<JS::GCVector<JSObject*, 0, js::SystemAllocPolicy>> mUncaughtRejections;
// Promises in this list have previously been reported as rejected
// (because they were in the above list), but the rejection was handled
// in the last turn of the event loop.
JS::PersistentRooted<JS::GCVector<JSObject*, 0, js::SystemAllocPolicy>> mConsumedRejections;
nsTArray<nsCOMPtr<nsISupports /* UncaughtRejectionObserver */ >> mUncaughtRejectionObservers;
private:
// A primary context owns the mRuntime. Non-main-thread contexts should always
// be primary. On the main thread, the primary context should be the first one
// created and the last one destroyed. Non-primary contexts are used for
// cooperatively scheduled threads.
bool mIsPrimaryContext;
CycleCollectedJSRuntime* mRuntime;
JSContext* mJSContext;
nsCOMPtr<nsIException> mPendingException;
nsThread* mOwningThread; // Manual refcounting to avoid include hell.
struct RunInMetastableStateData
{
nsCOMPtr<nsIRunnable> mRunnable;
uint32_t mRecursionDepth;
};
nsTArray<nsCOMPtr<nsIRunnable>> mStableStateEvents;
nsTArray<RunInMetastableStateData> mMetastableStateEvents;
uint32_t mBaseRecursionDepth;
bool mDoingStableStates;
bool mDisableMicroTaskCheckpoint;
};
} // namespace mozilla
#endif // mozilla_CycleCollectedJSContext_h