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
|
// Copyright 2024 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "components/performance_manager/scenario_api/performance_scenario_observer.h"
#include <atomic>
#include <utility>
#include "base/check.h"
#include "base/memory/scoped_refptr.h"
#include "base/no_destructor.h"
#include "base/notreached.h"
#include "base/observer_list.h"
#include "base/sequence_checker.h"
#include "base/synchronization/lock.h"
#include "base/types/pass_key.h"
#include "components/performance_manager/scenario_api/performance_scenario_memory.h"
#include "components/performance_manager/scenario_api/performance_scenarios.h"
namespace performance_scenarios {
namespace {
// The global pointers to PerformanceScenarioObserverLists are written from one
// thread, but read from several, so the pointers must be accessed under a lock.
// (As well as the pointed-to object having an atomic refcount.)
class LockedObserverListPtr {
public:
LockedObserverListPtr() = default;
~LockedObserverListPtr() = default;
LockedObserverListPtr(const LockedObserverListPtr&) = delete;
LockedObserverListPtr operator=(const LockedObserverListPtr&) = delete;
// Returns a copy of the pointer.
scoped_refptr<PerformanceScenarioObserverList> Get() {
base::AutoLock lock(lock_);
return observer_list_;
}
// Writes `observer_list` to the pointer, and returns the previous value.
scoped_refptr<PerformanceScenarioObserverList> Exchange(
scoped_refptr<PerformanceScenarioObserverList> observer_list) {
base::AutoLock lock(lock_);
return std::exchange(observer_list_, std::move(observer_list));
}
private:
base::Lock lock_;
scoped_refptr<PerformanceScenarioObserverList> observer_list_
GUARDED_BY(lock_);
};
LockedObserverListPtr& GetLockedObserverListPtrForScope(ScenarioScope scope) {
static base::NoDestructor<LockedObserverListPtr>
current_process_observer_list;
static base::NoDestructor<LockedObserverListPtr> global_observer_list;
switch (scope) {
case ScenarioScope::kCurrentProcess:
return *current_process_observer_list;
case ScenarioScope::kGlobal:
return *global_observer_list;
}
NOTREACHED();
}
} // namespace
MatchingScenarioObserver::MatchingScenarioObserver(ScenarioPattern pattern)
: pattern_(pattern) {
for (ScenarioScope scope : ScenarioScopes::All()) {
LastMatchNotification(scope) = CurrentScenariosMatch(scope, pattern_);
}
// NotifyIfScenarioMatchChanged must always run on the sequence that called
// PerformanceScenarioObserverList::AddMatchingObserver, but that might not be
// the constructor sequence.
DETACH_FROM_SEQUENCE(sequence_checker_);
}
MatchingScenarioObserver::~MatchingScenarioObserver() = default;
void MatchingScenarioObserver::NotifyIfScenarioMatchChanged(
ScenarioScope scope,
LoadingScenario loading_scenario,
InputScenario input_scenario) {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
bool matches_pattern =
ScenariosMatch(loading_scenario, input_scenario, pattern_);
bool last_matches_pattern =
std::exchange(LastMatchNotification(scope), matches_pattern);
if (last_matches_pattern != matches_pattern) {
OnScenarioMatchChanged(scope, matches_pattern);
}
}
bool& MatchingScenarioObserver::LastMatchNotification(ScenarioScope scope) {
DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
static_assert(static_cast<size_t>(ScenarioScopes::kMinValue) == 0,
"index will be wrong if enum doesn't start at 0");
return last_match_notifications_.at(static_cast<size_t>(scope));
}
// static
scoped_refptr<PerformanceScenarioObserverList>
PerformanceScenarioObserverList::GetForScope(ScenarioScope scope) {
return GetLockedObserverListPtrForScope(scope).Get();
}
void PerformanceScenarioObserverList::AddObserver(
PerformanceScenarioObserver* observer) {
observers_->AddObserver(observer);
}
void PerformanceScenarioObserverList::RemoveObserver(
PerformanceScenarioObserver* observer) {
observers_->RemoveObserver(observer);
}
void PerformanceScenarioObserverList::AddMatchingObserver(
MatchingScenarioObserver* matching_observer) {
matching_observers_->AddObserver(matching_observer);
}
void PerformanceScenarioObserverList::RemoveMatchingObserver(
MatchingScenarioObserver* matching_observer) {
matching_observers_->RemoveObserver(matching_observer);
}
void PerformanceScenarioObserverList::NotifyIfScenarioChanged(
base::Location location) {
base::AutoLock lock(lock_);
LoadingScenario loading_scenario =
GetLoadingScenario(scope_)->load(std::memory_order_relaxed);
if (loading_scenario != last_loading_scenario_) {
observers_->Notify(location,
&PerformanceScenarioObserver::OnLoadingScenarioChanged,
scope_, last_loading_scenario_, loading_scenario);
last_loading_scenario_ = loading_scenario;
}
InputScenario input_scenario =
GetInputScenario(scope_)->load(std::memory_order_relaxed);
if (input_scenario != last_input_scenario_) {
observers_->Notify(location,
&PerformanceScenarioObserver::OnInputScenarioChanged,
scope_, last_input_scenario_, input_scenario);
last_input_scenario_ = input_scenario;
}
matching_observers_->Notify(
location, &MatchingScenarioObserver::NotifyIfScenarioMatchChanged, scope_,
loading_scenario, input_scenario);
}
// static
void PerformanceScenarioObserverList::NotifyAllScopes(base::Location location) {
if (auto current_process_observers =
GetForScope(ScenarioScope::kCurrentProcess)) {
current_process_observers->NotifyIfScenarioChanged(location);
}
if (auto global_observers = GetForScope(ScenarioScope::kGlobal)) {
global_observers->NotifyIfScenarioChanged(location);
}
}
// static
void PerformanceScenarioObserverList::CreateForScope(
base::PassKey<ScopedReadOnlyScenarioMemory>,
ScenarioScope scope) {
auto old_ptr = GetLockedObserverListPtrForScope(scope).Exchange(
base::WrapRefCounted(new PerformanceScenarioObserverList(scope)));
CHECK(!old_ptr);
}
// static
void PerformanceScenarioObserverList::DestroyForScope(
base::PassKey<ScopedReadOnlyScenarioMemory>,
ScenarioScope scope) {
// Drop the main owning reference. Callers of GetForScope() might still have
// references, but no new caller can obtain a reference.
auto old_ptr = GetLockedObserverListPtrForScope(scope).Exchange(nullptr);
CHECK(old_ptr);
}
PerformanceScenarioObserverList::PerformanceScenarioObserverList(
ScenarioScope scope)
: scope_(scope),
last_loading_scenario_(
GetLoadingScenario(scope)->load(std::memory_order_relaxed)),
last_input_scenario_(
GetInputScenario(scope)->load(std::memory_order_relaxed)) {}
PerformanceScenarioObserverList::~PerformanceScenarioObserverList() = default;
} // namespace performance_scenarios
|
