//===-- ProcessRunLock.h ----------------------------------------*- C++ -*-===//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

//

//===----------------------------------------------------------------------===//

#ifndef LLDB_HOST_PROCESSRUNLOCK_H

#define LLDB_HOST_PROCESSRUNLOCK_H

#include <cstdint>

#include <ctime>

#include "lldb/lldb-defines.h"

/// Enumerations for broadcasting.

namespace lldb_private {

/// \class ProcessRunLock ProcessRunLock.h "lldb/Host/ProcessRunLock.h"

/// A class used to prevent the process from starting while other

/// threads are accessing its data, and prevent access to its data while it is

/// running.

class ProcessRunLock {

public:

  ProcessRunLock();

  ~ProcessRunLock();

  bool ReadTryLock();

  bool ReadUnlock();

  bool SetRunning();

  bool TrySetRunning();

  bool SetStopped();

  class ProcessRunLocker {

  public:

    ProcessRunLocker() = default;

    ~ProcessRunLocker() { Unlock(); }

    // Try to lock the read lock, but only do so if there are no writers.

    bool TryLock(ProcessRunLock *lock) {

      if (m_lock) {

        if (m_lock == lock)

          return true; // We already have this lock locked

        else

          Unlock();

      }

      if (lock) {

        if (lock->ReadTryLock()) {

          m_lock = lock;

          return true;

        }

      }

      return false;

    }

  protected:

    void Unlock() {

      if (m_lock) {

        m_lock->ReadUnlock();

        m_lock = nullptr;

      }

    }

    ProcessRunLock *m_lock = nullptr;

  private:

    ProcessRunLocker(const ProcessRunLocker &) = delete;

    const ProcessRunLocker &operator=(const ProcessRunLocker &) = delete;

  };

protected:

  lldb::rwlock_t m_rwlock;

  bool m_running = false;

private:

  ProcessRunLock(const ProcessRunLock &) = delete;

  const ProcessRunLock &operator=(const ProcessRunLock &) = delete;

};

} // namespace lldb_private

#endif // LLDB_HOST_PROCESSRUNLOCK_H