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#include "base/process_mutex.h"

#include "base/file_util.h"
#include "base/logging.h"
#include "testing/gunit.h"
#include "testing/mozctest.h"
#include "absl/status/status.h"
#include "absl/time/clock.h"
#include "absl/time/time.h"

#ifndef _WIN32
#include <unistd.h>

#include <cstdlib>
#endif  // _WIN32

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

class ProcessMutexTest : public testing::TestWithTempUserProfile {
 protected:
  void TearDown() override {
    ProcessMutex mutex(kName);
    if (absl::Status s = FileUtil::FileExists(mutex.lock_filename());
        !absl::IsNotFound(s)) {
      LOG(FATAL)
          << "Lock file unexpectedly remains or cannot check the existence: "
          << mutex.lock_filename() << ": " << s;
    }
  }
};

#if !defined(_WIN32)
TEST_F(ProcessMutexTest, ForkProcessMutexTest) {
  const pid_t pid = ::fork();
  if (pid == 0) {  // child process
    ProcessMutex m(kName);
    EXPECT_TRUE(m.Lock());
    absl::SleepFor(absl::Seconds(3));
    EXPECT_TRUE(m.UnLock());
    ::exit(0);
  } else if (pid > 0) {  // parent process
    ProcessMutex m(kName);
    absl::SleepFor(absl::Seconds(1));

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

    absl::SleepFor(absl::Seconds(5));

    // child process already finished, so now we can lock
    EXPECT_TRUE(m.Lock());
    EXPECT_TRUE(m.UnLock());
  } else {
    LOG(FATAL) << "fork() failed";
  }
}
#endif  // !_WIN32

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
