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// Copyright 2014 the V8 project 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 <cstring>
#include "src/base/platform/platform.h"
#include "src/base/platform/semaphore.h"
#include "src/base/platform/time.h"
#include "testing/gtest/include/gtest/gtest.h"
namespace v8 {
namespace base {
namespace {
static const char kAlphabet[] = "XKOAD";
static const size_t kAlphabetSize = sizeof(kAlphabet) - 1;
static const size_t kBufferSize = 987; // GCD(buffer size, alphabet size) = 1
static const size_t kDataSize = kBufferSize * kAlphabetSize * 10;
class ProducerThread final : public Thread {
public:
ProducerThread(char* buffer, Semaphore* free_space, Semaphore* used_space)
: Thread(Options("ProducerThread")),
buffer_(buffer),
free_space_(free_space),
used_space_(used_space) {}
void Run() override {
for (size_t n = 0; n < kDataSize; ++n) {
free_space_->Wait();
buffer_[n % kBufferSize] = kAlphabet[n % kAlphabetSize];
used_space_->Signal();
}
}
private:
char* buffer_;
Semaphore* const free_space_;
Semaphore* const used_space_;
};
class ConsumerThread final : public Thread {
public:
ConsumerThread(const char* buffer, Semaphore* free_space,
Semaphore* used_space)
: Thread(Options("ConsumerThread")),
buffer_(buffer),
free_space_(free_space),
used_space_(used_space) {}
void Run() override {
for (size_t n = 0; n < kDataSize; ++n) {
used_space_->Wait();
EXPECT_EQ(kAlphabet[n % kAlphabetSize], buffer_[n % kBufferSize]);
free_space_->Signal();
}
}
private:
const char* buffer_;
Semaphore* const free_space_;
Semaphore* const used_space_;
};
class WaitAndSignalThread final : public Thread {
public:
explicit WaitAndSignalThread(Semaphore* semaphore)
: Thread(Options("WaitAndSignalThread")), semaphore_(semaphore) {}
void Run() override {
for (int n = 0; n < 100; ++n) {
semaphore_->Wait();
ASSERT_FALSE(semaphore_->WaitFor(TimeDelta::FromMicroseconds(1)));
semaphore_->Signal();
}
}
private:
Semaphore* const semaphore_;
};
} // namespace
TEST(Semaphore, ProducerConsumer) {
char buffer[kBufferSize];
std::memset(buffer, 0, sizeof(buffer));
Semaphore free_space(kBufferSize);
Semaphore used_space(0);
ProducerThread producer_thread(buffer, &free_space, &used_space);
ConsumerThread consumer_thread(buffer, &free_space, &used_space);
producer_thread.Start();
consumer_thread.Start();
producer_thread.Join();
consumer_thread.Join();
}
TEST(Semaphore, WaitAndSignal) {
Semaphore semaphore(0);
WaitAndSignalThread t1(&semaphore);
WaitAndSignalThread t2(&semaphore);
t1.Start();
t2.Start();
// Make something available.
semaphore.Signal();
t1.Join();
t2.Join();
semaphore.Wait();
EXPECT_FALSE(semaphore.WaitFor(TimeDelta::FromMicroseconds(1)));
}
TEST(Semaphore, WaitFor) {
Semaphore semaphore(0);
// Semaphore not signalled - timeout.
ASSERT_FALSE(semaphore.WaitFor(TimeDelta::FromMicroseconds(0)));
ASSERT_FALSE(semaphore.WaitFor(TimeDelta::FromMicroseconds(100)));
ASSERT_FALSE(semaphore.WaitFor(TimeDelta::FromMicroseconds(1000)));
// Semaphore signalled - no timeout.
semaphore.Signal();
ASSERT_TRUE(semaphore.WaitFor(TimeDelta::FromMicroseconds(0)));
semaphore.Signal();
ASSERT_TRUE(semaphore.WaitFor(TimeDelta::FromMicroseconds(100)));
semaphore.Signal();
ASSERT_TRUE(semaphore.WaitFor(TimeDelta::FromMicroseconds(1000)));
}
} // namespace base
} // namespace v8
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