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#include "base/process_mutex.h"

#ifndef OS_WIN
#include <unistd.h>

#include <cstdlib>
#endif  // OS_WIN

#include "base/file_util.h"
#include "base/logging.h"
#include "base/system_util.h"
#include "base/util.h"
#include "testing/base/public/googletest.h"
#include "testing/base/public/gunit.h"
#include "absl/flags/flag.h"

namespace mozc {
namespace {
static const char kName[] = "process_mutex_test";

class ProcessMutexTest : public testing::Test {
 protected:
  void SetUp() override {
    original_user_profile_dir_ = SystemUtil::GetUserProfileDirectory();
    SystemUtil::SetUserProfileDirectory(absl::GetFlag(FLAGS_test_tmpdir));
  }

  void TearDown() override {
    ProcessMutex mutex(kName);
    if (FileUtil::FileExists(mutex.lock_filename())) {
      LOG(FATAL) << "Lock file unexpectedly remains: " << mutex.lock_filename();
    }

    SystemUtil::SetUserProfileDirectory(original_user_profile_dir_);
  }

 private:
  std::string original_user_profile_dir_;
};

#if !defined(OS_WIN)
TEST_F(ProcessMutexTest, ForkProcessMutexTest) {
  const pid_t pid = ::fork();
  if (pid == 0) {  // child process
    ProcessMutex m(kName);
    EXPECT_TRUE(m.Lock());
    Util::Sleep(3000);
    EXPECT_TRUE(m.UnLock());
    ::exit(0);
  } else if (pid > 0) {  // parent process
    ProcessMutex m(kName);
    Util::Sleep(1000);

    // kName should be locked by child
    EXPECT_FALSE(m.Lock());

    Util::Sleep(5000);

    // child process already finished, so now we can lock
    EXPECT_TRUE(m.Lock());
    EXPECT_TRUE(m.UnLock());
  } else {
    LOG(FATAL) << "fork() failed";
  }
}
#endif  // !OS_WIN

TEST_F(ProcessMutexTest, BasicTest) {
  ProcessMutex m1(kName);
  EXPECT_TRUE(m1.Lock());
  EXPECT_TRUE(m1.locked());

  ProcessMutex m2(kName);
  EXPECT_FALSE(m2.Lock());
  EXPECT_FALSE(m2.locked());

  ProcessMutex m3(kName);
  EXPECT_FALSE(m3.Lock());
  EXPECT_FALSE(m3.locked());

  EXPECT_TRUE(m1.UnLock());
  EXPECT_FALSE(m1.locked());

  EXPECT_TRUE(m2.Lock());
  EXPECT_TRUE(m2.locked());

  EXPECT_FALSE(m3.Lock());
  EXPECT_FALSE(m3.locked());
}

TEST_F(ProcessMutexTest, RecursiveLockTest) {
  ProcessMutex mutex(kName);
  EXPECT_TRUE(mutex.Lock());
  EXPECT_TRUE(mutex.locked());
  EXPECT_FALSE(mutex.Lock()) << "Recursive lock should fail.";
  EXPECT_TRUE(mutex.locked());
  EXPECT_TRUE(mutex.UnLock());
  EXPECT_FALSE(mutex.locked());
}

}  // namespace
}  // namespace mozc
