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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/Mutex.h"
#include "mozilla/StaticMutex.h"
#include "mozilla/TimeStamp.h"
#include "mozilla/Variant.h"
#include "mozilla/Logging.h"
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 nsIObserver;
namespace mozilla {
class LogModule;
}
// 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(!mIsInTimerThread);
// The nsITimer interface requires that its users keep a reference to the
// timers they use while those timers are initialized but have not yet
// fired. If this assert ever fails, it is a bug in the code that created
// and used the timer.
//
// Further, note that this should never fail even with a misbehaving user,
// because nsTimer::Release checks for a refcount of 1 with an armed timer
// (a timer whose only reference is from the timer thread) and when it hits
// this will remove the timer from the timer thread and thus destroy the
// last reference, preventing this situation from occurring.
MOZ_ASSERT(
mCallback.is<UnknownCallback>() || mEventTarget->IsOnCurrentThread(),
"Must not release mCallback off-target without canceling");
}
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);
int32_t GetGeneration() { return mGeneration; }
struct UnknownCallback {};
using InterfaceCallback = nsCOMPtr<nsITimerCallback>;
using ObserverCallback = nsCOMPtr<nsIObserver>;
/// A raw function pointer and its closed-over state, along with its name for
/// logging purposes.
struct FuncCallback {
nsTimerCallbackFunc mFunc;
void* mClosure;
const char* mName;
};
/// A callback defined by an owned closure and its name for logging purposes.
struct ClosureCallback {
std::function<void(nsITimer*)> mFunc;
const char* mName;
};
using Callback =
mozilla::Variant<UnknownCallback, InterfaceCallback, ObserverCallback,
FuncCallback, ClosureCallback>;
nsresult InitCommon(const mozilla::TimeDuration& aDelay, uint32_t aType,
Callback&& newCallback,
const mozilla::MutexAutoLock& aProofOfLock)
MOZ_REQUIRES(mMutex);
Callback& GetCallback() MOZ_REQUIRES(mMutex) {
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, const mozilla::MutexAutoLock& aProofOfLock)
MOZ_REQUIRES(mMutex);
bool IsInTimerThread() const { return mIsInTimerThread; }
void SetIsInTimerThread(bool aIsInTimerThread) {
mIsInTimerThread = aIsInTimerThread;
}
nsCOMPtr<nsIEventTarget> mEventTarget;
void LogFiring(const Callback& aCallback, uint8_t aType, uint32_t aDelay);
nsresult InitWithClosureCallback(std::function<void(nsITimer*)>&& aCallback,
const mozilla::TimeDuration& aDelay,
uint32_t aType, const char* aNameString);
// Is this timer currently referenced from a TimerThread::Entry?
// Note: It is cleared before the Entry is destroyed. Take() also sets it to
// false, to indicate it's no longer in the TimerThread's list. This Take()
// call is NOT made under the nsTimerImpl's mutex (all other
// SetIsInTimerThread calls are under the mutex). However, ALL accesses to
// mIsInTimerThread are under the TimerThread's Monitor lock, so consistency
// is guaranteed by that.
bool mIsInTimerThread;
// 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 MOZ_GUARDED_BY(mMutex);
// Never updated while in the TimerThread's timer list. Only updated
// before adding to that list or during nsTimerImpl::Fire(), when it has
// been removed from the TimerThread's list. TimerThread can access
// mTimeout of any timer in the list safely
mozilla::TimeStamp mTimeout;
RefPtr<nsITimer> mITimer MOZ_GUARDED_BY(mMutex);
mozilla::Mutex mMutex;
Callback mCallback MOZ_GUARDED_BY(mMutex);
// Counter because in rare cases we can Fire reentrantly
unsigned int mFiring MOZ_GUARDED_BY(mMutex);
static mozilla::StaticMutex sDeltaMutex;
static double sDeltaSum MOZ_GUARDED_BY(sDeltaMutex);
static double sDeltaSumSquared MOZ_GUARDED_BY(sDeltaMutex);
static double sDeltaNum MOZ_GUARDED_BY(sDeltaMutex);
};
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);
// NOTE: This constructor is not exposed on `nsITimer` as NS_FORWARD_SAFE_
// does not support forwarding rvalue references.
nsresult InitWithClosureCallback(std::function<void(nsITimer*)>&& aCallback,
const mozilla::TimeDuration& aDelay,
uint32_t aType, const char* aNameString) {
return mImpl ? mImpl->InitWithClosureCallback(std::move(aCallback), aDelay,
aType, aNameString)
: NS_ERROR_NULL_POINTER;
}
// 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(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;
};
class nsTimerManager final : public nsITimerManager {
public:
NS_DECL_ISUPPORTS
NS_DECL_NSITIMERMANAGER
private:
~nsTimerManager() = default;
};
#endif /* nsTimerImpl_h___ */
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