nextpnr/common/scope_lock.h

/*
 *  nextpnr -- Next Generation Place and Route
 *
 *  Copyright (C) 2021 Symbiflow Authors.
 *
 *  Permission to use, copy, modify, and/or distribute this software for any
 *  purpose with or without fee is hereby granted, provided that the above
 *  copyright notice and this permission notice appear in all copies.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 */

#ifndef SCOPE_LOCK_H
#define SCOPE_LOCK_H

#include <stdexcept>

namespace nextpnr {

// Provides a simple RAII locking object.  ScopeLock takes a lock when
// constructed, and releases the lock on destruction or if "unlock_early" is
// called.
//
// LockingObject must have a method "void lock(void)" and "void unlock(void)".
template <typename LockingObject> class ScopeLock
{
  public:
    ScopeLock(LockingObject *obj) : obj_(obj), locked_(false)
    {
        obj_->lock();
        locked_ = true;
    }
    ScopeLock(const ScopeLock &other) = delete;
    ScopeLock(const ScopeLock &&other) = delete;

    ~ScopeLock()
    {
        if (locked_) {
            obj_->unlock();
        }
    }
    void unlock_early()
    {
        if (!locked_) {
            throw std::runtime_error("Lock already released?");
        }
        locked_ = false;
        obj_->unlock();
    }

  private:
    LockingObject *obj_;
    bool locked_;
};

}; // namespace nextpnr

#endif /* SCOPE_LOCK_H */