1 /*
2 * Copyright (C) 2008 Apple Inc. All Rights Reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE COMPUTER, INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 *
25 */
26
27 #include "config.h"
28 #include "core/frame/DOMTimer.h"
29
30 #include "core/dom/ExecutionContext.h"
31 #include "core/inspector/InspectorInstrumentation.h"
32 #include "core/inspector/InspectorTraceEvents.h"
33 #include "platform/Logging.h"
34 #include "platform/TraceEvent.h"
35 #include "wtf/CurrentTime.h"
36
37 namespace blink {
38
39 static const int maxIntervalForUserGestureForwarding = 1000; // One second matches Gecko.
40 static const int maxTimerNestingLevel = 5;
41 static const double oneMillisecond = 0.001;
42 // Chromium uses a minimum timer interval of 4ms. We'd like to go
43 // lower; however, there are poorly coded websites out there which do
44 // create CPU-spinning loops. Using 4ms prevents the CPU from
45 // spinning too busily and provides a balance between CPU spinning and
46 // the smallest possible interval timer.
47 static const double minimumInterval = 0.004;
48
49 static int timerNestingLevel = 0;
50
shouldForwardUserGesture(int interval,int nestingLevel)51 static inline bool shouldForwardUserGesture(int interval, int nestingLevel)
52 {
53 return UserGestureIndicator::processingUserGesture()
54 && interval <= maxIntervalForUserGestureForwarding
55 && nestingLevel == 1; // Gestures should not be forwarded to nested timers.
56 }
57
hiddenPageAlignmentInterval()58 double DOMTimer::hiddenPageAlignmentInterval()
59 {
60 // Timers on hidden pages are aligned so that they fire once per
61 // second at most.
62 return 1.0;
63 }
64
visiblePageAlignmentInterval()65 double DOMTimer::visiblePageAlignmentInterval()
66 {
67 // Alignment does not apply to timers on visible pages.
68 return 0;
69 }
70
install(ExecutionContext * context,PassOwnPtr<ScheduledAction> action,int timeout,bool singleShot)71 int DOMTimer::install(ExecutionContext* context, PassOwnPtr<ScheduledAction> action, int timeout, bool singleShot)
72 {
73 int timeoutID = context->installNewTimeout(action, timeout, singleShot);
74 TRACE_EVENT_INSTANT1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline"), "TimerInstall", "data", InspectorTimerInstallEvent::data(context, timeoutID, timeout, singleShot));
75 TRACE_EVENT_INSTANT1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline.stack"), "CallStack", "stack", InspectorCallStackEvent::currentCallStack());
76 // FIXME(361045): remove InspectorInstrumentation calls once DevTools Timeline migrates to tracing.
77 InspectorInstrumentation::didInstallTimer(context, timeoutID, timeout, singleShot);
78 WTF_LOG(Timers, "DOMTimer::install: timeoutID = %d, timeout = %d, singleShot = %d", timeoutID, timeout, singleShot ? 1 : 0);
79 return timeoutID;
80 }
81
removeByID(ExecutionContext * context,int timeoutID)82 void DOMTimer::removeByID(ExecutionContext* context, int timeoutID)
83 {
84 WTF_LOG(Timers, "DOMTimer::removeByID: timeoutID = %d", timeoutID);
85 context->removeTimeoutByID(timeoutID);
86 TRACE_EVENT_INSTANT1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline"), "TimerRemove", "data", InspectorTimerRemoveEvent::data(context, timeoutID));
87 TRACE_EVENT_INSTANT1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline.stack"), "CallStack", "stack", InspectorCallStackEvent::currentCallStack());
88 // FIXME(361045): remove InspectorInstrumentation calls once DevTools Timeline migrates to tracing.
89 InspectorInstrumentation::didRemoveTimer(context, timeoutID);
90 }
91
DOMTimer(ExecutionContext * context,PassOwnPtr<ScheduledAction> action,int interval,bool singleShot,int timeoutID)92 DOMTimer::DOMTimer(ExecutionContext* context, PassOwnPtr<ScheduledAction> action, int interval, bool singleShot, int timeoutID)
93 : SuspendableTimer(context)
94 , m_timeoutID(timeoutID)
95 , m_nestingLevel(timerNestingLevel + 1)
96 , m_action(action)
97 {
98 ASSERT(timeoutID > 0);
99 if (shouldForwardUserGesture(interval, m_nestingLevel))
100 m_userGestureToken = UserGestureIndicator::currentToken();
101
102 double intervalMilliseconds = std::max(oneMillisecond, interval * oneMillisecond);
103 if (intervalMilliseconds < minimumInterval && m_nestingLevel >= maxTimerNestingLevel)
104 intervalMilliseconds = minimumInterval;
105 if (singleShot)
106 startOneShot(intervalMilliseconds, FROM_HERE);
107 else
108 startRepeating(intervalMilliseconds, FROM_HERE);
109 }
110
~DOMTimer()111 DOMTimer::~DOMTimer()
112 {
113 }
114
timeoutID() const115 int DOMTimer::timeoutID() const
116 {
117 return m_timeoutID;
118 }
119
fired()120 void DOMTimer::fired()
121 {
122 ExecutionContext* context = executionContext();
123 timerNestingLevel = m_nestingLevel;
124 ASSERT(!context->activeDOMObjectsAreSuspended());
125 // Only the first execution of a multi-shot timer should get an affirmative user gesture indicator.
126 UserGestureIndicator gestureIndicator(m_userGestureToken.release());
127
128 TRACE_EVENT1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline"), "TimerFire", "data", InspectorTimerFireEvent::data(context, m_timeoutID));
129 // FIXME(361045): remove InspectorInstrumentation calls once DevTools Timeline migrates to tracing.
130 InspectorInstrumentationCookie cookie = InspectorInstrumentation::willFireTimer(context, m_timeoutID);
131
132 // Simple case for non-one-shot timers.
133 if (isActive()) {
134 if (repeatInterval() && repeatInterval() < minimumInterval) {
135 m_nestingLevel++;
136 if (m_nestingLevel >= maxTimerNestingLevel)
137 augmentRepeatInterval(minimumInterval - repeatInterval());
138 }
139
140 WTF_LOG(Timers, "DOMTimer::fired: m_timeoutID = %d, repeatInterval = %f, m_action = %p", m_timeoutID, repeatInterval(), m_action.get());
141
142 // No access to member variables after this point, it can delete the timer.
143 m_action->execute(context);
144
145 InspectorInstrumentation::didFireTimer(cookie);
146
147 return;
148 }
149
150 WTF_LOG(Timers, "DOMTimer::fired: m_timeoutID = %d, one-shot, m_action = %p", m_timeoutID, m_action.get());
151
152 // Delete timer before executing the action for one-shot timers.
153 OwnPtr<ScheduledAction> action = m_action.release();
154
155 // This timer is being deleted; no access to member variables allowed after this point.
156 context->removeTimeoutByID(m_timeoutID);
157
158 action->execute(context);
159
160 InspectorInstrumentation::didFireTimer(cookie);
161 TRACE_EVENT_INSTANT1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline"), "UpdateCounters", "data", InspectorUpdateCountersEvent::data());
162
163 timerNestingLevel = 0;
164 }
165
contextDestroyed()166 void DOMTimer::contextDestroyed()
167 {
168 SuspendableTimer::contextDestroyed();
169 }
170
stop()171 void DOMTimer::stop()
172 {
173 SuspendableTimer::stop();
174 // Need to release JS objects potentially protected by ScheduledAction
175 // because they can form circular references back to the ExecutionContext
176 // which will cause a memory leak.
177 m_action.clear();
178 }
179
alignedFireTime(double fireTime) const180 double DOMTimer::alignedFireTime(double fireTime) const
181 {
182 double alignmentInterval = executionContext()->timerAlignmentInterval();
183 if (alignmentInterval) {
184 double currentTime = monotonicallyIncreasingTime();
185 if (fireTime <= currentTime)
186 return fireTime;
187
188 // When a repeating timer is scheduled for exactly the
189 // background page alignment interval, because it's impossible
190 // for the timer to be rescheduled instantaneously, it misses
191 // every other fire time. Avoid this by looking at the next
192 // fire time rounded both down and up.
193
194 double alignedTimeRoundedDown = floor(fireTime / alignmentInterval) * alignmentInterval;
195 double alignedTimeRoundedUp = ceil(fireTime / alignmentInterval) * alignmentInterval;
196
197 // If the version rounded down is in the past, discard it
198 // immediately.
199
200 if (alignedTimeRoundedDown <= currentTime)
201 return alignedTimeRoundedUp;
202
203 // Only use the rounded-down time if it's within a certain
204 // tolerance of the fire time. This avoids speeding up timers
205 // on background pages in the common case.
206
207 if (fireTime - alignedTimeRoundedDown < minimumInterval)
208 return alignedTimeRoundedDown;
209
210 return alignedTimeRoundedUp;
211 }
212
213 return fireTime;
214 }
215
216 } // namespace blink
217