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1 // Copyright 2012 The Chromium Authors
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 #include <android/looper.h>
6 #include <stdarg.h>
7 #include <string.h>
8 
9 #include "base/android/path_utils.h"
10 #include "base/files/file_path.h"
11 #include "base/logging.h"
12 #include "base/memory/raw_ptr.h"
13 #include "base/memory/singleton.h"
14 #include "base/message_loop/message_pump.h"
15 #include "base/message_loop/message_pump_android.h"
16 #include "base/path_service.h"
17 #include "base/synchronization/waitable_event.h"
18 #include "base/test/multiprocess_test.h"
19 
20 namespace {
21 
22 base::FilePath* g_test_data_dir = nullptr;
23 
24 struct RunState {
RunState__anon4c7e9c480111::RunState25   RunState(base::MessagePump::Delegate* delegate, int run_depth)
26       : delegate(delegate),
27         run_depth(run_depth),
28         should_quit(false) {
29   }
30 
31   raw_ptr<base::MessagePump::Delegate> delegate;
32 
33   // Used to count how many Run() invocations are on the stack.
34   int run_depth;
35 
36   // Used to flag that the current Run() invocation should return ASAP.
37   bool should_quit;
38 };
39 
40 RunState* g_state = nullptr;
41 
42 // A singleton WaitableEvent wrapper so we avoid a busy loop in
43 // MessagePumpForUIStub. Other platforms use the native event loop which blocks
44 // when there are no pending messages.
45 class Waitable {
46  public:
GetInstance()47   static Waitable* GetInstance() {
48     return base::Singleton<Waitable,
49                            base::LeakySingletonTraits<Waitable>>::get();
50   }
51 
52   Waitable(const Waitable&) = delete;
53   Waitable& operator=(const Waitable&) = delete;
54 
55   // Signals that there are more work to do.
Signal()56   void Signal() { waitable_event_.Signal(); }
57 
58   // Blocks until more work is scheduled.
Block()59   void Block() { waitable_event_.Wait(); }
60 
Quit()61   void Quit() {
62     g_state->should_quit = true;
63     Signal();
64   }
65 
66  private:
67   friend struct base::DefaultSingletonTraits<Waitable>;
68 
Waitable()69   Waitable()
70       : waitable_event_(base::WaitableEvent::ResetPolicy::AUTOMATIC,
71                         base::WaitableEvent::InitialState::NOT_SIGNALED) {}
72 
73   base::WaitableEvent waitable_event_;
74 };
75 
76 // The MessagePumpForUI implementation for test purpose.
77 class MessagePumpForUIStub : public base::MessagePumpForUI {
78  public:
MessagePumpForUIStub()79   MessagePumpForUIStub() : base::MessagePumpForUI() { Waitable::GetInstance(); }
~MessagePumpForUIStub()80   ~MessagePumpForUIStub() override {}
81 
82   // In tests, there isn't a native thread, as such RunLoop::Run() should be
83   // used to run the loop instead of attaching and delegating to the native
84   // loop. As such, this override ignores the Attach() request.
Attach(base::MessagePump::Delegate * delegate)85   void Attach(base::MessagePump::Delegate* delegate) override {}
86 
Run(base::MessagePump::Delegate * delegate)87   void Run(base::MessagePump::Delegate* delegate) override {
88     // The following was based on message_pump_glib.cc, except we're using a
89     // WaitableEvent since there are no native message loop to use.
90     RunState state(delegate, g_state ? g_state->run_depth + 1 : 1);
91 
92     RunState* previous_state = g_state;
93     g_state = &state;
94 
95     // When not nested we can use the looper, otherwise fall back
96     // to the stub implementation.
97     if (g_state->run_depth > 1) {
98       RunNested(delegate);
99     } else {
100       SetQuit(false);
101       SetDelegate(delegate);
102 
103       // Pump the loop once in case we're starting off idle as ALooper_pollOnce
104       // will never return in that case.
105       ScheduleWork();
106       while (true) {
107         // Waits for either the delayed, or non-delayed fds to be signalled,
108         // calling either OnDelayedLooperCallback, or
109         // OnNonDelayedLooperCallback, respectively. This uses Android's Looper
110         // implementation, which is based off of epoll.
111         ALooper_pollOnce(-1, nullptr, nullptr, nullptr);
112         if (ShouldQuit())
113           break;
114       }
115     }
116 
117     g_state = previous_state;
118   }
119 
RunNested(base::MessagePump::Delegate * delegate)120   void RunNested(base::MessagePump::Delegate* delegate) {
121     bool more_work_is_plausible = true;
122 
123     for (;;) {
124       if (!more_work_is_plausible) {
125         Waitable::GetInstance()->Block();
126         if (g_state->should_quit)
127           break;
128       }
129 
130       Delegate::NextWorkInfo next_work_info = g_state->delegate->DoWork();
131       more_work_is_plausible = next_work_info.is_immediate();
132       if (g_state->should_quit)
133         break;
134 
135       if (more_work_is_plausible)
136         continue;
137 
138       more_work_is_plausible = g_state->delegate->DoIdleWork();
139       if (g_state->should_quit)
140         break;
141 
142       more_work_is_plausible |= !next_work_info.delayed_run_time.is_max();
143     }
144   }
145 
Quit()146   void Quit() override {
147     CHECK(g_state);
148     if (g_state->run_depth > 1) {
149       Waitable::GetInstance()->Quit();
150     } else {
151       MessagePumpForUI::Quit();
152     }
153   }
154 
ScheduleWork()155   void ScheduleWork() override {
156     if (g_state && g_state->run_depth > 1) {
157       Waitable::GetInstance()->Signal();
158     } else {
159       MessagePumpForUI::ScheduleWork();
160     }
161   }
162 
ScheduleDelayedWork(const Delegate::NextWorkInfo & next_work_info)163   void ScheduleDelayedWork(
164       const Delegate::NextWorkInfo& next_work_info) override {
165     if (g_state && g_state->run_depth > 1) {
166       Waitable::GetInstance()->Signal();
167     } else {
168       MessagePumpForUI::ScheduleDelayedWork(next_work_info);
169     }
170   }
171 };
172 
CreateMessagePumpForUIStub()173 std::unique_ptr<base::MessagePump> CreateMessagePumpForUIStub() {
174   return std::unique_ptr<base::MessagePump>(new MessagePumpForUIStub());
175 }
176 
177 // Provides the test path for paths overridden during tests.
GetTestProviderPath(int key,base::FilePath * result)178 bool GetTestProviderPath(int key, base::FilePath* result) {
179   switch (key) {
180     // On Android, our tests don't have permission to write to DIR_MODULE.
181     // gtest/test_runner.py pushes data to external storage.
182     // TODO(agrieve): Stop overriding DIR_ANDROID_APP_DATA.
183     // https://crbug.com/617734
184     // Instead DIR_ASSETS should be used to discover assets file location in
185     // tests.
186     case base::DIR_ANDROID_APP_DATA:
187     case base::DIR_ASSETS:
188     case base::DIR_SRC_TEST_DATA_ROOT:
189     case base::DIR_OUT_TEST_DATA_ROOT:
190       CHECK(g_test_data_dir != nullptr);
191       *result = *g_test_data_dir;
192       return true;
193     default:
194       return false;
195   }
196 }
197 
InitPathProvider(int key)198 void InitPathProvider(int key) {
199   base::FilePath path;
200   // If failed to override the key, that means the way has not been registered.
201   if (GetTestProviderPath(key, &path) &&
202       !base::PathService::Override(key, path)) {
203     base::PathService::RegisterProvider(&GetTestProviderPath, key, key + 1);
204   }
205 }
206 
207 }  // namespace
208 
209 namespace base {
210 
InitAndroidTestPaths(const FilePath & test_data_dir)211 void InitAndroidTestPaths(const FilePath& test_data_dir) {
212   if (g_test_data_dir) {
213     CHECK(test_data_dir == *g_test_data_dir);
214     return;
215   }
216   g_test_data_dir = new FilePath(test_data_dir);
217   InitPathProvider(DIR_ANDROID_APP_DATA);
218   InitPathProvider(DIR_ASSETS);
219   InitPathProvider(DIR_SRC_TEST_DATA_ROOT);
220   InitPathProvider(DIR_OUT_TEST_DATA_ROOT);
221 }
222 
InitAndroidTestMessageLoop()223 void InitAndroidTestMessageLoop() {
224   // NOTE something else such as a JNI call may have already overridden the UI
225   // factory.
226   if (!MessagePump::IsMessagePumpForUIFactoryOveridden())
227     MessagePump::OverrideMessagePumpForUIFactory(&CreateMessagePumpForUIStub);
228 }
229 
230 }  // namespace base
231