deskflow/src/lib/net/SocketMultiplexer.h
2025-07-07 17:53:56 +01:00

105 lines
3.2 KiB
C++

/*
* Deskflow -- mouse and keyboard sharing utility
* SPDX-FileCopyrightText: (C) 2012 - 2016 Symless Ltd.
* SPDX-FileCopyrightText: (C) 2004 Chris Schoeneman
* SPDX-License-Identifier: GPL-2.0-only WITH LicenseRef-OpenSSL-Exception
*/
#pragma once
#include "arch/IArchNetwork.h"
#include <list>
#include <map>
template <class T> class CondVar;
class Mutex;
class Thread;
class ISocket;
class ISocketMultiplexerJob;
//! Socket multiplexer
/*!
A socket multiplexer services multiple sockets simultaneously.
*/
class SocketMultiplexer
{
public:
SocketMultiplexer();
SocketMultiplexer(SocketMultiplexer const &) = delete;
SocketMultiplexer(SocketMultiplexer &&) = delete;
~SocketMultiplexer();
SocketMultiplexer &operator=(SocketMultiplexer const &) = delete;
SocketMultiplexer &operator=(SocketMultiplexer &&) = delete;
//! @name manipulators
//@{
void addSocket(ISocket *, ISocketMultiplexerJob *);
void removeSocket(ISocket *);
//@}
//! @name accessors
//@{
// maybe belongs on ISocketMultiplexer
static SocketMultiplexer *getInstance();
//@}
private:
// list of jobs. we use a list so we can safely iterate over it
// while other threads modify it.
using SocketJobs = std::list<ISocketMultiplexerJob *>;
using JobCursor = SocketJobs::iterator;
using SocketJobMap = std::map<ISocket *, JobCursor>;
// service sockets. the service thread will only access m_sockets
// and m_update while m_pollable and m_polling are true. all other
// threads must only modify these when m_pollable and m_polling are
// false. only the service thread sets m_polling.
[[noreturn]] void serviceThread(void *);
// create, iterate, and destroy a cursor. a cursor is used to
// safely iterate through the job list while other threads modify
// the list. it works by inserting a dummy item in the list and
// moving that item through the list. the dummy item will never
// be removed by other edits so an iterator pointing at the item
// remains valid until we remove the dummy item in deleteCursor().
// nextCursor() finds the next non-dummy item, moves our dummy
// item just past it, and returns an iterator for the non-dummy
// item. all cursor calls lock the mutex for their duration.
JobCursor newCursor();
JobCursor nextCursor(JobCursor);
void deleteCursor(JobCursor);
// lock out locking the job list. this blocks if another thread
// has already locked out locking. once it returns, only the
// calling thread will be able to lock the job list after any
// current lock is released.
void lockJobListLock();
// lock the job list. this blocks if the job list is already
// locked. the calling thread must have called requestJobLock.
void lockJobList();
// unlock the job list and the lock out on locking.
void unlockJobList();
private:
Mutex *m_mutex = nullptr;
Thread *m_thread = nullptr;
bool m_update = false;
CondVar<bool> *m_jobsReady = nullptr;
CondVar<bool> *m_jobListLock = nullptr;
CondVar<bool> *m_jobListLockLocked = nullptr;
Thread *m_jobListLocker = nullptr;
Thread *m_jobListLockLocker = nullptr;
SocketJobs m_socketJobs = {};
SocketJobMap m_socketJobMap = {};
ISocketMultiplexerJob *m_cursorMark = nullptr;
};