1/*
2 * Copyright (C) 2014 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 INC. AND ITS CONTRIBUTORS ``AS IS''
14 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
15 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
17 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
18 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO , PROCUREMENT OF
19 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
20 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
21 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
22 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
23 * THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#include "config.h"
27#include "ProcessThrottler.h"
28
29#include "Logging.h"
30#include "ProcessThrottlerClient.h"
31
32namespace WebKit {
33
34static const Seconds processSuspensionTimeout { 30_s };
35
36ProcessThrottler::ProcessThrottler(ProcessThrottlerClient& process, bool shouldTakeUIBackgroundAssertion)
37 : m_process(process)
38 , m_suspendTimer(RunLoop::main(), this, &ProcessThrottler::suspendTimerFired)
39 , m_foregroundCounter([this](RefCounterEvent) { updateAssertion(); })
40 , m_backgroundCounter([this](RefCounterEvent) { updateAssertion(); })
41 , m_shouldTakeUIBackgroundAssertion(shouldTakeUIBackgroundAssertion)
42{
43}
44
45AssertionState ProcessThrottler::assertionState()
46{
47 ASSERT(!m_suspendTimer.isActive());
48
49 if (m_foregroundCounter.value())
50 return AssertionState::Foreground;
51 if (m_backgroundCounter.value())
52 return AssertionState::Background;
53 return AssertionState::Suspended;
54}
55
56void ProcessThrottler::updateAssertionNow()
57{
58 m_suspendTimer.stop();
59 if (m_assertion) {
60 auto newState = assertionState();
61 if (m_assertion->state() == newState)
62 return;
63 RELEASE_LOG(ProcessSuspension, "%p - ProcessThrottler::updateAssertionNow() updating process assertion state to %u (foregroundActivities: %lu, backgroundActivities: %lu)", this, newState, m_foregroundCounter.value(), m_backgroundCounter.value());
64 m_assertion->setState(newState);
65 m_process.didSetAssertionState(newState);
66 }
67}
68
69void ProcessThrottler::updateAssertion()
70{
71 bool shouldBeRunnable = this->shouldBeRunnable();
72
73 // If the process is currently runnable but will be suspended then first give it a chance to complete what it was doing
74 // and clean up - move it to the background and send it a message to notify. Schedule a timeout so it can't stay running
75 // in the background for too long.
76 if (m_assertion && m_assertion->state() != AssertionState::Suspended && !shouldBeRunnable) {
77 ++m_suspendMessageCount;
78 RELEASE_LOG(ProcessSuspension, "%p - ProcessThrottler::updateAssertion() sending PrepareToSuspend IPC", this);
79 m_process.sendPrepareToSuspend();
80 m_suspendTimer.startOneShot(processSuspensionTimeout);
81 m_assertion->setState(AssertionState::Background);
82 m_process.didSetAssertionState(AssertionState::Background);
83 return;
84 }
85
86 if (shouldBeRunnable) {
87 // If we're currently waiting for the Web process to do suspension cleanup, but no longer need to be suspended, tell the Web process to cancel the cleanup.
88 if (m_suspendTimer.isActive())
89 m_process.sendCancelPrepareToSuspend();
90
91 if ((m_assertion && m_assertion->state() == AssertionState::Suspended) || m_uiAssertionExpired) {
92 m_process.sendProcessDidResume();
93 m_uiAssertionExpired = false;
94 }
95 }
96
97 updateAssertionNow();
98}
99
100void ProcessThrottler::didConnectToProcess(ProcessID pid)
101{
102 RELEASE_LOG(ProcessSuspension, "%p - ProcessThrottler::didConnectToProcess(%d)", this, pid);
103
104 m_suspendTimer.stop();
105 if (m_shouldTakeUIBackgroundAssertion)
106 m_assertion = std::make_unique<ProcessAndUIAssertion>(pid, "Web content visibility"_s, assertionState());
107 else
108 m_assertion = std::make_unique<ProcessAssertion>(pid, "Web content visibility"_s, assertionState());
109 m_process.didSetAssertionState(assertionState());
110 m_assertion->setClient(*this);
111}
112
113void ProcessThrottler::suspendTimerFired()
114{
115 updateAssertionNow();
116}
117
118void ProcessThrottler::processReadyToSuspend()
119{
120 if (!--m_suspendMessageCount)
121 updateAssertionNow();
122 ASSERT(m_suspendMessageCount >= 0);
123}
124
125void ProcessThrottler::didCancelProcessSuspension()
126{
127 if (!--m_suspendMessageCount)
128 updateAssertionNow();
129 ASSERT(m_suspendMessageCount >= 0);
130}
131
132void ProcessThrottler::uiAssertionWillExpireImminently()
133{
134 m_process.sendProcessWillSuspendImminently();
135 m_uiAssertionExpired = true;
136}
137
138}
139