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// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "third_party/mojo/src/mojo/edk/system/mutex.h"
#include <stdlib.h>
#include "base/threading/platform_thread.h"
#include "mojo/public/cpp/system/macros.h"
#include "testing/gtest/include/gtest/gtest.h"
#include "third_party/mojo/src/mojo/edk/system/test_utils.h"
namespace mojo {
namespace system {
namespace {
// Sleeps for a "very small" amount of time.
void EpsilonRandomSleep() {
test::Sleep(test::DeadlineFromMilliseconds(rand() % 20));
}
// Basic test to make sure that Lock()/Unlock()/TryLock() don't crash ----------
class BasicMutexTestThread : public base::PlatformThread::Delegate {
public:
explicit BasicMutexTestThread(Mutex* mutex) : mutex_(mutex), acquired_(0) {}
void ThreadMain() override {
for (int i = 0; i < 10; i++) {
mutex_->Lock();
mutex_->AssertHeld();
acquired_++;
mutex_->Unlock();
}
for (int i = 0; i < 10; i++) {
mutex_->Lock();
mutex_->AssertHeld();
acquired_++;
EpsilonRandomSleep();
mutex_->Unlock();
}
for (int i = 0; i < 10; i++) {
if (mutex_->TryLock()) {
mutex_->AssertHeld();
acquired_++;
EpsilonRandomSleep();
mutex_->Unlock();
}
}
}
int acquired() const { return acquired_; }
private:
Mutex* mutex_;
int acquired_;
MOJO_DISALLOW_COPY_AND_ASSIGN(BasicMutexTestThread);
};
TEST(MutexTest, Basic) {
Mutex mutex;
BasicMutexTestThread thread(&mutex);
base::PlatformThreadHandle handle;
ASSERT_TRUE(base::PlatformThread::Create(0, &thread, &handle));
int acquired = 0;
for (int i = 0; i < 5; i++) {
mutex.Lock();
mutex.AssertHeld();
acquired++;
mutex.Unlock();
}
for (int i = 0; i < 10; i++) {
mutex.Lock();
mutex.AssertHeld();
acquired++;
EpsilonRandomSleep();
mutex.Unlock();
}
for (int i = 0; i < 10; i++) {
if (mutex.TryLock()) {
mutex.AssertHeld();
acquired++;
EpsilonRandomSleep();
mutex.Unlock();
}
}
for (int i = 0; i < 5; i++) {
mutex.Lock();
mutex.AssertHeld();
acquired++;
EpsilonRandomSleep();
mutex.Unlock();
}
base::PlatformThread::Join(handle);
EXPECT_GE(acquired, 20);
EXPECT_GE(thread.acquired(), 20);
}
// Test that TryLock() works as expected ---------------------------------------
class TryLockTestThread : public base::PlatformThread::Delegate {
public:
explicit TryLockTestThread(Mutex* mutex) : mutex_(mutex), got_lock_(false) {}
void ThreadMain() override MOJO_NO_THREAD_SAFETY_ANALYSIS {
got_lock_ = mutex_->TryLock();
if (got_lock_) {
mutex_->AssertHeld();
mutex_->Unlock();
}
}
bool got_lock() const { return got_lock_; }
private:
Mutex* mutex_;
bool got_lock_;
MOJO_DISALLOW_COPY_AND_ASSIGN(TryLockTestThread);
};
TEST(MutexTest, TryLock) MOJO_NO_THREAD_SAFETY_ANALYSIS {
Mutex mutex;
ASSERT_TRUE(mutex.TryLock());
// We now have the mutex....
// This thread will not be able to get the mutex.
{
TryLockTestThread thread(&mutex);
base::PlatformThreadHandle handle;
ASSERT_TRUE(base::PlatformThread::Create(0, &thread, &handle));
base::PlatformThread::Join(handle);
ASSERT_FALSE(thread.got_lock());
}
mutex.Unlock();
// This thread will....
{
TryLockTestThread thread(&mutex);
base::PlatformThreadHandle handle;
ASSERT_TRUE(base::PlatformThread::Create(0, &thread, &handle));
base::PlatformThread::Join(handle);
ASSERT_TRUE(thread.got_lock());
// But it released it....
ASSERT_TRUE(mutex.TryLock());
}
mutex.Unlock();
}
// Tests that mutexes actually exclude -----------------------------------------
class MutexLockTestThread : public base::PlatformThread::Delegate {
public:
MutexLockTestThread(Mutex* mutex, int* value)
: mutex_(mutex), value_(value) {}
// Static helper which can also be called from the main thread.
static void DoStuff(Mutex* mutex, int* value) {
for (int i = 0; i < 40; i++) {
mutex->Lock();
int v = *value;
EpsilonRandomSleep();
*value = v + 1;
mutex->Unlock();
}
}
void ThreadMain() override { DoStuff(mutex_, value_); }
private:
Mutex* mutex_;
int* value_;
MOJO_DISALLOW_COPY_AND_ASSIGN(MutexLockTestThread);
};
TEST(MutexTest, MutexTwoThreads) {
Mutex mutex;
int value = 0;
MutexLockTestThread thread(&mutex, &value);
base::PlatformThreadHandle handle;
ASSERT_TRUE(base::PlatformThread::Create(0, &thread, &handle));
MutexLockTestThread::DoStuff(&mutex, &value);
base::PlatformThread::Join(handle);
EXPECT_EQ(2 * 40, value);
}
TEST(MutexTest, MutexFourThreads) {
Mutex mutex;
int value = 0;
MutexLockTestThread thread1(&mutex, &value);
MutexLockTestThread thread2(&mutex, &value);
MutexLockTestThread thread3(&mutex, &value);
base::PlatformThreadHandle handle1;
base::PlatformThreadHandle handle2;
base::PlatformThreadHandle handle3;
ASSERT_TRUE(base::PlatformThread::Create(0, &thread1, &handle1));
ASSERT_TRUE(base::PlatformThread::Create(0, &thread2, &handle2));
ASSERT_TRUE(base::PlatformThread::Create(0, &thread3, &handle3));
MutexLockTestThread::DoStuff(&mutex, &value);
base::PlatformThread::Join(handle1);
base::PlatformThread::Join(handle2);
base::PlatformThread::Join(handle3);
EXPECT_EQ(4 * 40, value);
}
// MutexLocker -----------------------------------------------------------------
TEST(MutexTest, MutexLocker) {
Mutex mutex;
{
MutexLocker locker(&mutex);
mutex.AssertHeld();
}
// The destruction of |locker| should unlock |mutex|.
ASSERT_TRUE(mutex.TryLock());
mutex.AssertHeld();
mutex.Unlock();
}
} // namespace
} // namespace system
} // namespace mojo
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