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 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 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 65 double DOMTimer::visiblePageAlignmentInterval() 66 { 67 // Alignment does not apply to timers on visible pages. 68 return 0; 69 } 70 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 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 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 } 110 111 DOMTimer::~DOMTimer() 112 { 113 } 114 115 int DOMTimer::timeoutID() const 116 { 117 return m_timeoutID; 118 } 119 120 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 } 165 166 void DOMTimer::contextDestroyed() 167 { 168 SuspendableTimer::contextDestroyed(); 169 } 170 171 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 } 179 180 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
