strawberry-audio-player-win.../ext/libstrawberry-common/core/messagereply.h

100 lines
2.9 KiB
C++

/* This file is part of Strawberry.
Copyright 2011, David Sansome <me@davidsansome.com>
Copyright 2018-2021, Jonas Kvinge <jonas@jkvinge.net>
Strawberry is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Strawberry is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with Strawberry. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef MESSAGEREPLY_H
#define MESSAGEREPLY_H
#include <QtGlobal>
#include <QObject>
#include <QSemaphore>
#include <QString>
#include <QTimer>
#include "core/logging.h"
// Base QObject for a reply future class that is returned immediately for requests that will occur in the background.
// Similar to QNetworkReply. Use MessageReply instead.
class _MessageReplyBase : public QObject {
Q_OBJECT
public:
explicit _MessageReplyBase(QObject *parent = nullptr);
virtual int id() const = 0;
bool is_finished() const { return finished_; }
bool is_successful() const { return success_; }
// Waits for the reply to finish by waiting on a semaphore. Never call this from the MessageHandler's thread or it will block forever.
// Returns true if the call was successful.
bool WaitForFinished();
void Abort();
signals:
void Finished();
protected:
bool finished_;
bool success_;
QSemaphore semaphore_;
};
// A reply future class that is returned immediately for requests that will occur in the background. Similar to QNetworkReply.
template <typename MessageType>
class MessageReply : public _MessageReplyBase {
public:
explicit MessageReply(const MessageType &request_message, QObject *parent = nullptr);
int id() const override { return request_message_.id(); }
const MessageType &request_message() const { return request_message_; }
const MessageType &message() const { return reply_message_; }
void SetReply(const MessageType &message);
private:
MessageType request_message_;
MessageType reply_message_;
};
template<typename MessageType>
MessageReply<MessageType>::MessageReply(const MessageType &request_message, QObject *parent) : _MessageReplyBase(parent) {
request_message_.MergeFrom(request_message);
}
template<typename MessageType>
void MessageReply<MessageType>::SetReply(const MessageType &message) {
Q_ASSERT(!finished_);
reply_message_.MergeFrom(message);
finished_ = true;
success_ = true;
qLog(Debug) << "Releasing ID" << id() << "(finished)";
// Delay the signal as workaround to fix the signal periodically not emitted.
QTimer::singleShot(1, this, &_MessageReplyBase::Finished);
semaphore_.release();
}
#endif // MESSAGEREPLY_H