File: Timer.h

package info (click to toggle)
webkit2gtk 2.48.5-1
  • links: PTS, VCS
  • area: main
  • in suites: forky, sid
  • size: 429,764 kB
  • sloc: cpp: 3,697,587; javascript: 194,444; ansic: 169,997; python: 46,499; asm: 19,295; ruby: 18,528; perl: 16,602; xml: 4,650; yacc: 2,360; sh: 2,098; java: 1,993; lex: 1,327; pascal: 366; makefile: 298
file content (288 lines) | stat: -rw-r--r-- 9,573 bytes parent folder | download | duplicates (6)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
/*
 * Copyright (C) 2006-2023 Apple Inc.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
 */

#pragma once

#include "ThreadTimers.h"
#include <functional>
#include <wtf/CheckedRef.h>
#include <wtf/Function.h>
#include <wtf/MonotonicTime.h>
#include <wtf/Noncopyable.h>
#include <wtf/RunLoop.h>
#include <wtf/Seconds.h>
#include <wtf/TZoneMalloc.h>
#include <wtf/Threading.h>
#include <wtf/TypeTraits.h>
#include <wtf/Vector.h>
#include <wtf/WeakPtr.h>

#if PLATFORM(IOS_FAMILY)
#include "WebCoreThread.h"
#endif

namespace WebCore {
class TimerAlignment;
}

namespace WTF {
template<typename T> struct IsDeprecatedWeakRefSmartPointerException;
template<> struct IsDeprecatedWeakRefSmartPointerException<WebCore::TimerAlignment> : std::true_type { };
}

namespace WebCore {

class TimerAlignment : public CanMakeWeakPtr<TimerAlignment> {
public:
    virtual ~TimerAlignment() = default;
    virtual std::optional<MonotonicTime> alignedFireTime(bool hasReachedMaxNestingLevel, MonotonicTime) const = 0;
};

class TimerBase {
    WTF_MAKE_TZONE_ALLOCATED(TimerBase);
    WTF_MAKE_NONCOPYABLE(TimerBase);
public:
    WEBCORE_EXPORT TimerBase();
    WEBCORE_EXPORT virtual ~TimerBase();

    // TimerBase's destructor inspects Ref<Thread> m_thread, which won't work if we are moved-from.
    TimerBase(TimerBase&&) = delete;
    TimerBase& operator=(TimerBase&&) = delete;

    WEBCORE_EXPORT void start(Seconds nextFireInterval, Seconds repeatInterval);

    void startRepeating(Seconds repeatInterval) { start(repeatInterval, repeatInterval); }
    void startOneShot(Seconds delay) { start(delay, 0_s); }

    inline void stop();
    inline bool isActive() const;

    MonotonicTime nextFireTime() const { return m_heapItemWithBitfields.pointer() ? m_heapItemWithBitfields.pointer()->time : MonotonicTime { }; }
    WEBCORE_EXPORT Seconds nextFireInterval() const;
    Seconds nextUnalignedFireInterval() const;
    Seconds repeatInterval() const { return m_repeatInterval; }

    void setTimerAlignment(TimerAlignment& alignment) { m_alignment = alignment; }
    TimerAlignment* timerAlignment() { return m_alignment.get(); }

    bool hasReachedMaxNestingLevel() const { return bitfields().hasReachedMaxNestingLevel; }
    void setHasReachedMaxNestingLevel(bool);

    void augmentFireInterval(Seconds delta) { setNextFireTime(m_heapItemWithBitfields.pointer()->time + delta); }
    void augmentRepeatInterval(Seconds delta) { augmentFireInterval(delta); m_repeatInterval += delta; }

    void didChangeAlignmentInterval();

    WEBCORE_EXPORT static void fireTimersInNestedEventLoop();

protected:
    struct TimerBitfields {
        uint8_t hasReachedMaxNestingLevel : 1 { false };
        uint8_t shouldRestartWhenTimerFires : 1 { false }; // DeferrableOneShotTimer
    };

    TimerBitfields bitfields() const { return std::bit_cast<TimerBitfields>(m_heapItemWithBitfields.type()); }
    void setBitfields(const TimerBitfields& bitfields) { return m_heapItemWithBitfields.setType(std::bit_cast<uint8_t>(bitfields)); }

private:
    virtual void fired() = 0;

    WEBCORE_EXPORT void stopSlowCase();

    void checkConsistency() const;
    void checkHeapIndex() const;

    void setNextFireTime(MonotonicTime);

    bool inHeap() const { return m_heapItemWithBitfields.pointer() && m_heapItemWithBitfields.pointer()->isInHeap(); }

    bool hasValidHeapPosition() const;
    void updateHeapIfNeeded(MonotonicTime oldTime);

    void heapDecreaseKey();
    void heapDelete();
    void heapDeleteMin();
    void heapIncreaseKey();
    void heapInsert();
    void heapPop();
    void heapPopMin();
    static void heapDeleteNullMin(ThreadTimerHeap&);

    WeakPtr<TimerAlignment> m_alignment;
    MonotonicTime m_unalignedNextFireTime; // m_nextFireTime not considering alignment interval
    Seconds m_repeatInterval; // 0 if not repeating

    CompactRefPtrTuple<ThreadTimerHeapItem, uint8_t> m_heapItemWithBitfields;
    Ref<Thread> m_thread { Thread::current() };

    friend class ThreadTimers;
    friend class TimerHeapLessThanFunction;
    friend class TimerHeapReference;
};

class Timer : public TimerBase {
    WTF_MAKE_TZONE_ALLOCATED_EXPORT(Timer, WEBCORE_EXPORT);
public:
    static void schedule(Seconds delay, Function<void()>&& function)
    {
        auto* timer = new Timer([] { });
        timer->m_function = [timer, function = WTFMove(function)] {
            function();
            delete timer;
        };
        timer->startOneShot(delay);
    }

    template<typename TimerFiredClass, typename TimerFiredBaseClass>
    requires (WTF::HasRefPtrMemberFunctions<TimerFiredClass>::value)
    Timer(TimerFiredClass& object, void (TimerFiredBaseClass::*function)())
        : m_function([objectPtr = &object, function] {
            Ref protectedObject { *objectPtr };
            (objectPtr->*function)();
        })
    {
    }


    template<typename TimerFiredClass, typename TimerFiredBaseClass>
    requires (WTF::HasCheckedPtrMemberFunctions<TimerFiredClass>::value && !WTF::HasRefPtrMemberFunctions<TimerFiredClass>::value)
    Timer(TimerFiredClass& object, void (TimerFiredBaseClass::*function)())
        : m_function([objectPtr = &object, function] {
            CheckedRef checkedObject { *objectPtr };
            (objectPtr->*function)();
        })
    {
    }

    // FIXME: This constructor isn't as safe as the other ones and should ideally be removed.
    template <typename TimerFiredClass, typename TimerFiredBaseClass>
    requires (!WTF::HasRefPtrMemberFunctions<TimerFiredClass>::value && !WTF::HasCheckedPtrMemberFunctions<TimerFiredClass>::value)
    Timer(TimerFiredClass& object, void (TimerFiredBaseClass::*function)())
        : m_function(std::bind(function, &object))
    {
        static_assert(WTF::IsDeprecatedTimerSmartPointerException<std::remove_cv_t<TimerFiredClass>>::value,
            "Classes that use Timer should be ref-counted or CanMakeCheckedPtr. Please do not add new exceptions."
        );
    }

    Timer(Function<void()>&& function)
        : m_function(WTFMove(function))
    {
    }

private:
    void fired() override
    {
        m_function();
    }
    
    Function<void()> m_function;
};

inline void TimerBase::stop()
{
    if (m_heapItemWithBitfields.pointer())
        stopSlowCase();
}

inline bool TimerBase::isActive() const
{
    // FIXME: Write this in terms of USE(WEB_THREAD) instead of PLATFORM(IOS_FAMILY).
#if !PLATFORM(IOS_FAMILY)
    ASSERT(m_thread.ptr() == &Thread::current());
#else
    ASSERT(WebThreadIsCurrent() || pthread_main_np() || m_thread.ptr() == &Thread::current());
#endif // PLATFORM(IOS_FAMILY)
    return static_cast<bool>(nextFireTime());
}

inline void TimerBase::setHasReachedMaxNestingLevel(bool value)
{
    auto values = bitfields();
    values.hasReachedMaxNestingLevel = value;
    setBitfields(values);
}

class DeferrableOneShotTimer : protected TimerBase {
    WTF_MAKE_TZONE_ALLOCATED_EXPORT(DeferrableOneShotTimer, WEBCORE_EXPORT);
public:
    template<typename TimerFiredClass>
    DeferrableOneShotTimer(TimerFiredClass& object, void (TimerFiredClass::*function)(), Seconds delay)
        : DeferrableOneShotTimer(std::bind(function, &object), delay)
    {
    }

    DeferrableOneShotTimer(Function<void()>&& function, Seconds delay)
        : m_function(WTFMove(function))
        , m_delay(delay)
    {
    }

    void restart()
    {
        // Setting this boolean is much more efficient than calling startOneShot
        // again, which might result in rescheduling the system timer which
        // can be quite expensive.

        if (isActive()) {
            setShouldRestartWhenTimerFires(true);
            return;
        }
        startOneShot(m_delay);
    }

    void stop()
    {
        setShouldRestartWhenTimerFires(false);
        TimerBase::stop();
    }

    using TimerBase::isActive;

private:
    void fired() override
    {
        if (bitfields().shouldRestartWhenTimerFires) {
            setShouldRestartWhenTimerFires(false);
            startOneShot(m_delay);
            return;
        }

        m_function();
    }

    void setShouldRestartWhenTimerFires(bool value)
    {
        auto values = bitfields();
        values.shouldRestartWhenTimerFires = value;
        setBitfields(values);
    }

    Function<void()> m_function;

    Seconds m_delay;
};

}