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/* -*- 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 nsTimerImpl_h___
#define nsTimerImpl_h___
#include "nsITimer.h"
#include "nsIEventTarget.h"
#include "nsIObserver.h"
#include "nsCOMPtr.h"
#include "mozilla/Attributes.h"
#include "mozilla/Logging.h"
#include "mozilla/Mutex.h"
#include "mozilla/TimeStamp.h"
#include "mozilla/Variant.h"
#ifdef MOZ_TASK_TRACER
# include "TracedTaskCommon.h"
#endif
extern mozilla::LogModule* GetTimerLog();
#define NS_TIMER_CID \
{ /* 5ff24248-1dd2-11b2-8427-fbab44f29bc8 */ \
0x5ff24248, 0x1dd2, 0x11b2, { \
0x84, 0x27, 0xfb, 0xab, 0x44, 0xf2, 0x9b, 0xc8 \
} \
}
class nsTimerImplHolder;
// TimerThread, nsTimerEvent, and nsTimer have references to these. nsTimer has
// a separate lifecycle so we can Cancel() the underlying timer when the user of
// the nsTimer has let go of its last reference.
class nsTimerImpl {
~nsTimerImpl() { MOZ_ASSERT(!mHolder); }
public:
typedef mozilla::TimeStamp TimeStamp;
nsTimerImpl(nsITimer* aTimer, nsIEventTarget* aTarget);
NS_INLINE_DECL_THREADSAFE_REFCOUNTING(nsTimerImpl)
NS_DECL_NON_VIRTUAL_NSITIMER
static nsresult Startup();
static void Shutdown();
void SetDelayInternal(uint32_t aDelay, TimeStamp aBase = TimeStamp::Now());
void CancelImpl(bool aClearITimer);
void Fire(int32_t aGeneration);
#ifdef MOZ_TASK_TRACER
void GetTLSTraceInfo();
mozilla::tasktracer::TracedTaskCommon GetTracedTask();
#endif
int32_t GetGeneration() { return mGeneration; }
struct Callback {
Callback() : mType(Type::Unknown), mName(Nothing), mClosure(nullptr) {
mCallback.c = nullptr;
}
Callback(const Callback& other) : Callback() { *this = other; }
enum class Type : uint8_t {
Unknown = 0,
Interface = 1,
Function = 2,
Observer = 3,
};
Callback& operator=(const Callback& other) {
if (this != &other) {
clear();
mType = other.mType;
switch (mType) {
case Type::Unknown:
break;
case Type::Interface:
mCallback.i = other.mCallback.i;
NS_ADDREF(mCallback.i);
break;
case Type::Function:
mCallback.c = other.mCallback.c;
break;
case Type::Observer:
mCallback.o = other.mCallback.o;
NS_ADDREF(mCallback.o);
break;
}
mName = other.mName;
mClosure = other.mClosure;
}
return *this;
}
~Callback() { clear(); }
void clear() {
if (mType == Type::Interface) {
NS_RELEASE(mCallback.i);
} else if (mType == Type::Observer) {
NS_RELEASE(mCallback.o);
}
mType = Type::Unknown;
}
void swap(Callback& other) {
std::swap(mType, other.mType);
std::swap(mCallback, other.mCallback);
std::swap(mName, other.mName);
std::swap(mClosure, other.mClosure);
}
Type mType;
union CallbackUnion {
nsTimerCallbackFunc c;
// These refcounted references are managed manually, as they are in a
// union
nsITimerCallback* MOZ_OWNING_REF i;
nsIObserver* MOZ_OWNING_REF o;
} mCallback;
// |Name| is a tagged union type representing one of (a) nothing, (b) a
// string, or (c) a function. mozilla::Variant doesn't naturally handle the
// "nothing" case, so we define a dummy type and value (which is unused and
// so the exact value doesn't matter) for it.
typedef const int NameNothing;
typedef const char* NameString;
typedef nsTimerNameCallbackFunc NameFunc;
typedef mozilla::Variant<NameNothing, NameString, NameFunc> Name;
static const NameNothing Nothing;
Name mName;
void* mClosure;
};
nsresult InitCommon(uint32_t aDelayMS, uint32_t aType,
Callback&& newCallback);
nsresult InitCommon(const mozilla::TimeDuration& aDelay, uint32_t aType,
Callback&& newCallback);
Callback& GetCallback() {
mMutex.AssertCurrentThreadOwns();
return mCallback;
}
bool IsRepeating() const {
static_assert(nsITimer::TYPE_ONE_SHOT < nsITimer::TYPE_REPEATING_SLACK,
"invalid ordering of timer types!");
static_assert(
nsITimer::TYPE_REPEATING_SLACK < nsITimer::TYPE_REPEATING_PRECISE,
"invalid ordering of timer types!");
static_assert(nsITimer::TYPE_REPEATING_PRECISE <
nsITimer::TYPE_REPEATING_PRECISE_CAN_SKIP,
"invalid ordering of timer types!");
return mType >= nsITimer::TYPE_REPEATING_SLACK &&
mType < nsITimer::TYPE_ONE_SHOT_LOW_PRIORITY;
}
bool IsLowPriority() const {
return mType == nsITimer::TYPE_ONE_SHOT_LOW_PRIORITY ||
mType == nsITimer::TYPE_REPEATING_SLACK_LOW_PRIORITY;
}
bool IsSlack() const {
return mType == nsITimer::TYPE_REPEATING_SLACK ||
mType == nsITimer::TYPE_REPEATING_SLACK_LOW_PRIORITY;
}
void GetName(nsACString& aName);
void SetHolder(nsTimerImplHolder* aHolder);
nsCOMPtr<nsIEventTarget> mEventTarget;
void LogFiring(const Callback& aCallback, uint8_t aType, uint32_t aDelay);
nsresult InitWithFuncCallbackCommon(nsTimerCallbackFunc aFunc, void* aClosure,
uint32_t aDelay, uint32_t aType,
const Callback::Name& aName);
// This weak reference must be cleared by the nsTimerImplHolder by calling
// SetHolder(nullptr) before the holder is destroyed.
nsTimerImplHolder* mHolder;
// These members are set by the initiating thread, when the timer's type is
// changed and during the period where it fires on that thread.
uint8_t mType;
// The generation number of this timer, re-generated each time the timer is
// initialized so one-shot timers can be canceled and re-initialized by the
// arming thread without any bad race conditions.
// Updated only after this timer has been removed from the timer thread.
int32_t mGeneration;
mozilla::TimeDuration mDelay;
// Updated only after this timer has been removed from the timer thread.
mozilla::TimeStamp mTimeout;
#ifdef MOZ_TASK_TRACER
mozilla::tasktracer::TracedTaskCommon mTracedTask;
#endif
static double sDeltaSum;
static double sDeltaSumSquared;
static double sDeltaNum;
RefPtr<nsITimer> mITimer;
mozilla::Mutex mMutex;
Callback mCallback;
// Counter because in rare cases we can Fire reentrantly
unsigned int mFiring;
};
class nsTimer final : public nsITimer {
explicit nsTimer(nsIEventTarget* aTarget)
: mImpl(new nsTimerImpl(this, aTarget)) {}
virtual ~nsTimer();
public:
friend class TimerThread;
friend class nsTimerEvent;
NS_DECL_THREADSAFE_ISUPPORTS
NS_FORWARD_SAFE_NSITIMER(mImpl);
virtual size_t SizeOfIncludingThis(
mozilla::MallocSizeOf aMallocSizeOf) const override;
// Create a timer targeting the given target. nullptr indicates that the
// current thread should be used as the timer's target.
static RefPtr<nsTimer> WithEventTarget(nsIEventTarget* aTarget);
static nsresult XPCOMConstructor(nsISupports* aOuter, REFNSIID aIID,
void** aResult);
private:
// nsTimerImpl holds a strong ref to us. When our refcount goes to 1, we will
// null this to break the cycle.
RefPtr<nsTimerImpl> mImpl;
};
// A class that holds on to an nsTimerImpl. This lets the nsTimerImpl object
// directly instruct its holder to forget the timer, avoiding list lookups.
class nsTimerImplHolder {
public:
explicit nsTimerImplHolder(nsTimerImpl* aTimerImpl) : mTimerImpl(aTimerImpl) {
if (mTimerImpl) {
mTimerImpl->SetHolder(this);
}
}
~nsTimerImplHolder() {
if (mTimerImpl) {
mTimerImpl->SetHolder(nullptr);
}
}
void Forget(nsTimerImpl* aTimerImpl) {
if (MOZ_UNLIKELY(!mTimerImpl)) {
return;
}
MOZ_ASSERT(aTimerImpl == mTimerImpl);
mTimerImpl->SetHolder(nullptr);
mTimerImpl = nullptr;
}
protected:
RefPtr<nsTimerImpl> mTimerImpl;
};
#endif /* nsTimerImpl_h___ */
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