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// Copyright 2016 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 "base/task_scheduler/scheduler_lock.h"
#include <stdlib.h>
#include "base/compiler_specific.h"
#include "base/macros.h"
#include "base/rand_util.h"
#include "base/synchronization/waitable_event.h"
#include "base/task_scheduler/test_utils.h"
#include "base/threading/platform_thread.h"
#include "base/threading/simple_thread.h"
#include "testing/gtest/include/gtest/gtest.h"
namespace base {
namespace internal {
namespace {
// Adapted from base::Lock's BasicLockTestThread to make sure
// Acquire()/Release() don't crash.
class BasicLockTestThread : public SimpleThread {
public:
explicit BasicLockTestThread(SchedulerLock* lock)
: SimpleThread("BasicLockTestThread"),
lock_(lock),
acquired_(0) {}
int acquired() const { return acquired_; }
private:
void Run() override {
for (int i = 0; i < 10; i++) {
lock_->Acquire();
acquired_++;
lock_->Release();
}
for (int i = 0; i < 10; i++) {
lock_->Acquire();
acquired_++;
PlatformThread::Sleep(TimeDelta::FromMilliseconds(base::RandInt(0, 19)));
lock_->Release();
}
}
SchedulerLock* const lock_;
int acquired_;
DISALLOW_COPY_AND_ASSIGN(BasicLockTestThread);
};
class BasicLockAcquireAndWaitThread : public SimpleThread {
public:
explicit BasicLockAcquireAndWaitThread(SchedulerLock* lock)
: SimpleThread("BasicLockAcquireAndWaitThread"),
lock_(lock),
lock_acquire_event_(WaitableEvent::ResetPolicy::AUTOMATIC,
WaitableEvent::InitialState::NOT_SIGNALED),
main_thread_continue_event_(WaitableEvent::ResetPolicy::AUTOMATIC,
WaitableEvent::InitialState::NOT_SIGNALED) {
}
void WaitForLockAcquisition() {
lock_acquire_event_.Wait();
}
void ContinueMain() {
main_thread_continue_event_.Signal();
}
private:
void Run() override {
lock_->Acquire();
lock_acquire_event_.Signal();
main_thread_continue_event_.Wait();
lock_->Release();
}
SchedulerLock* const lock_;
WaitableEvent lock_acquire_event_;
WaitableEvent main_thread_continue_event_;
DISALLOW_COPY_AND_ASSIGN(BasicLockAcquireAndWaitThread);
};
TEST(TaskSchedulerLock, Basic) {
SchedulerLock lock;
BasicLockTestThread thread(&lock);
thread.Start();
int acquired = 0;
for (int i = 0; i < 5; i++) {
lock.Acquire();
acquired++;
lock.Release();
}
for (int i = 0; i < 10; i++) {
lock.Acquire();
acquired++;
PlatformThread::Sleep(TimeDelta::FromMilliseconds(base::RandInt(0, 19)));
lock.Release();
}
for (int i = 0; i < 5; i++) {
lock.Acquire();
acquired++;
PlatformThread::Sleep(TimeDelta::FromMilliseconds(base::RandInt(0, 19)));
lock.Release();
}
thread.Join();
EXPECT_EQ(acquired, 20);
EXPECT_EQ(thread.acquired(), 20);
}
TEST(TaskSchedulerLock, AcquirePredecessor) {
SchedulerLock predecessor;
SchedulerLock lock(&predecessor);
predecessor.Acquire();
lock.Acquire();
lock.Release();
predecessor.Release();
}
TEST(TaskSchedulerLock, AcquirePredecessorWrongOrder) {
SchedulerLock predecessor;
SchedulerLock lock(&predecessor);
EXPECT_DCHECK_DEATH({
lock.Acquire();
predecessor.Acquire();
}, "");
}
TEST(TaskSchedulerLock, AcquireNonPredecessor) {
SchedulerLock lock1;
SchedulerLock lock2;
EXPECT_DCHECK_DEATH({
lock1.Acquire();
lock2.Acquire();
}, "");
}
TEST(TaskSchedulerLock, AcquireMultipleLocksInOrder) {
SchedulerLock lock1;
SchedulerLock lock2(&lock1);
SchedulerLock lock3(&lock2);
lock1.Acquire();
lock2.Acquire();
lock3.Acquire();
lock3.Release();
lock2.Release();
lock1.Release();
}
TEST(TaskSchedulerLock, AcquireMultipleLocksInTheMiddleOfAChain) {
SchedulerLock lock1;
SchedulerLock lock2(&lock1);
SchedulerLock lock3(&lock2);
lock2.Acquire();
lock3.Acquire();
lock3.Release();
lock2.Release();
}
TEST(TaskSchedulerLock, AcquireMultipleLocksNoTransitivity) {
SchedulerLock lock1;
SchedulerLock lock2(&lock1);
SchedulerLock lock3(&lock2);
EXPECT_DCHECK_DEATH({
lock1.Acquire();
lock3.Acquire();
}, "");
}
TEST(TaskSchedulerLock, AcquireLocksDifferentThreadsSafely) {
SchedulerLock lock1;
SchedulerLock lock2;
BasicLockAcquireAndWaitThread thread(&lock1);
thread.Start();
lock2.Acquire();
thread.WaitForLockAcquisition();
thread.ContinueMain();
thread.Join();
lock2.Release();
}
TEST(TaskSchedulerLock,
AcquireLocksWithPredecessorDifferentThreadsSafelyPredecessorFirst) {
// A lock and its predecessor may be safely acquired on different threads.
// This Thread Other Thread
// predecessor.Acquire()
// lock.Acquire()
// predecessor.Release()
// lock.Release()
SchedulerLock predecessor;
SchedulerLock lock(&predecessor);
predecessor.Acquire();
BasicLockAcquireAndWaitThread thread(&lock);
thread.Start();
thread.WaitForLockAcquisition();
predecessor.Release();
thread.ContinueMain();
thread.Join();
}
TEST(TaskSchedulerLock,
AcquireLocksWithPredecessorDifferentThreadsSafelyPredecessorLast) {
// A lock and its predecessor may be safely acquired on different threads.
// This Thread Other Thread
// lock.Acquire()
// predecessor.Acquire()
// lock.Release()
// predecessor.Release()
SchedulerLock predecessor;
SchedulerLock lock(&predecessor);
lock.Acquire();
BasicLockAcquireAndWaitThread thread(&predecessor);
thread.Start();
thread.WaitForLockAcquisition();
lock.Release();
thread.ContinueMain();
thread.Join();
}
TEST(TaskSchedulerLock,
AcquireLocksWithPredecessorDifferentThreadsSafelyNoInterference) {
// Acquisition of an unrelated lock on another thread should not affect a
// legal lock acquisition with a predecessor on this thread.
// This Thread Other Thread
// predecessor.Acquire()
// unrelated.Acquire()
// lock.Acquire()
// unrelated.Release()
// lock.Release()
// predecessor.Release();
SchedulerLock predecessor;
SchedulerLock lock(&predecessor);
predecessor.Acquire();
SchedulerLock unrelated;
BasicLockAcquireAndWaitThread thread(&unrelated);
thread.Start();
thread.WaitForLockAcquisition();
lock.Acquire();
thread.ContinueMain();
thread.Join();
lock.Release();
predecessor.Release();
}
TEST(TaskSchedulerLock, SelfReferentialLock) {
struct SelfReferentialLock {
SelfReferentialLock() : lock(&lock) {}
SchedulerLock lock;
};
EXPECT_DCHECK_DEATH({ SelfReferentialLock lock; }, "");
}
TEST(TaskSchedulerLock, PredecessorCycle) {
struct LockCycle {
LockCycle() : lock1(&lock2), lock2(&lock1) {}
SchedulerLock lock1;
SchedulerLock lock2;
};
EXPECT_DCHECK_DEATH({ LockCycle cycle; }, "");
}
TEST(TaskSchedulerLock, PredecessorLongerCycle) {
struct LockCycle {
LockCycle()
: lock1(&lock5),
lock2(&lock1),
lock3(&lock2),
lock4(&lock3),
lock5(&lock4) {}
SchedulerLock lock1;
SchedulerLock lock2;
SchedulerLock lock3;
SchedulerLock lock4;
SchedulerLock lock5;
};
EXPECT_DCHECK_DEATH({ LockCycle cycle; }, "");
}
} // namespace
} // namespace internal
} // namespace base
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