// Copyright 2018 The Fuchsia 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 "peridot/bin/ledger/lock/lock.h"

#include <lib/callback/capture.h>
#include <lib/fit/function.h>
#include <lib/fxl/memory/weak_ptr.h>

namespace lock {
namespace {
class LockImpl : public Lock {
 public:
  LockImpl() : weak_ptr_factory_(this) {}

  ~LockImpl() override {
    if (serialization_callback_) {
      serialization_callback_();
    }
  }

  coroutine::ContinuationStatus Acquire(
      coroutine::CoroutineHandler* const handler,
      callback::OperationSerializer* const serializer) {
    return SyncCall(handler, [weak_this = weak_ptr_factory_.GetWeakPtr(),
                              serializer](fit::function<void()> sync_callback) {
      serializer->Serialize<>(
          [] {},
          [weak_this, sync_callback = std::move(sync_callback)](
              fit::closure serialization_callback) mutable {
            // Moving sync_callback to the stack as the serialization_callback
            // might delete this closure.
            auto sync_callback_local = std::move(sync_callback);
            if (weak_this) {
              weak_this->serialization_callback_ =
                  std::move(serialization_callback);
            } else {
              serialization_callback();
            }
            sync_callback_local();
          });
    });
  }

 private:
  fit::closure serialization_callback_;

  fxl::WeakPtrFactory<LockImpl> weak_ptr_factory_;
  FXL_DISALLOW_COPY_AND_ASSIGN(LockImpl);
};
}  // namespace

coroutine::ContinuationStatus AcquireLock(
    coroutine::CoroutineHandler* const handler,
    callback::OperationSerializer* const serializer,
    std::unique_ptr<Lock>* lock) {
  std::unique_ptr<LockImpl> impl = std::make_unique<LockImpl>();
  coroutine::ContinuationStatus status = impl->Acquire(handler, serializer);
  if (status == coroutine::ContinuationStatus::OK) {
    *lock = std::move(impl);
  }
  return status;
}

}  // namespace lock