pcsx2/3rdparty/wxwidgets3.0/include/wx/msgqueue.h

169 lines
4.8 KiB
C++

///////////////////////////////////////////////////////////////////////////////
// Name: wx/msqqueue.h
// Purpose: Message queues for inter-thread communication
// Author: Evgeniy Tarassov
// Created: 2007-10-31
// Copyright: (C) 2007 TT-Solutions SARL
// Licence: wxWindows licence
///////////////////////////////////////////////////////////////////////////////
#ifndef _WX_MSGQUEUE_H_
#define _WX_MSGQUEUE_H_
// ----------------------------------------------------------------------------
// headers
// ----------------------------------------------------------------------------
#include "wx/thread.h"
#if wxUSE_THREADS
#include "wx/stopwatch.h"
#include "wx/beforestd.h"
#include <queue>
#include "wx/afterstd.h"
enum wxMessageQueueError
{
wxMSGQUEUE_NO_ERROR = 0, // operation completed successfully
wxMSGQUEUE_TIMEOUT, // no messages received before timeout expired
wxMSGQUEUE_MISC_ERROR // some unexpected (and fatal) error has occurred
};
// ---------------------------------------------------------------------------
// Message queue allows passing message between threads.
//
// This class is typically used for communicating between the main and worker
// threads. The main thread calls Post() and the worker thread calls Receive().
//
// For this class a message is an object of arbitrary type T. Notice that
// typically there must be some special message indicating that the thread
// should terminate as there is no other way to gracefully shutdown a thread
// waiting on the message queue.
// ---------------------------------------------------------------------------
template <typename T>
class wxMessageQueue
{
public:
// The type of the messages transported by this queue
typedef T Message;
// Default ctor creates an initially empty queue
wxMessageQueue()
: m_conditionNotEmpty(m_mutex)
{
}
// Add a message to this queue and signal the threads waiting for messages.
//
// This method is safe to call from multiple threads in parallel.
wxMessageQueueError Post(const Message& msg)
{
wxMutexLocker locker(m_mutex);
wxCHECK( locker.IsOk(), wxMSGQUEUE_MISC_ERROR );
m_messages.push(msg);
m_conditionNotEmpty.Signal();
return wxMSGQUEUE_NO_ERROR;
}
// Remove all messages from the queue.
//
// This method is meant to be called from the same thread(s) that call
// Post() to discard any still pending requests if they became unnecessary.
wxMessageQueueError Clear()
{
wxCHECK( IsOk(), wxMSGQUEUE_MISC_ERROR );
wxMutexLocker locker(m_mutex);
std::queue<T> empty;
std::swap(m_messages, empty);
return wxMSGQUEUE_NO_ERROR;
}
// Wait no more than timeout milliseconds until a message becomes available.
//
// Setting timeout to 0 is equivalent to an infinite timeout. See Receive().
wxMessageQueueError ReceiveTimeout(long timeout, T& msg)
{
wxCHECK( IsOk(), wxMSGQUEUE_MISC_ERROR );
wxMutexLocker locker(m_mutex);
wxCHECK( locker.IsOk(), wxMSGQUEUE_MISC_ERROR );
const wxMilliClock_t waitUntil = wxGetLocalTimeMillis() + timeout;
while ( m_messages.empty() )
{
wxCondError result = m_conditionNotEmpty.WaitTimeout(timeout);
if ( result == wxCOND_NO_ERROR )
continue;
wxCHECK( result == wxCOND_TIMEOUT, wxMSGQUEUE_MISC_ERROR );
const wxMilliClock_t now = wxGetLocalTimeMillis();
if ( now >= waitUntil )
return wxMSGQUEUE_TIMEOUT;
timeout = (waitUntil - now).ToLong();
wxASSERT(timeout > 0);
}
msg = m_messages.front();
m_messages.pop();
return wxMSGQUEUE_NO_ERROR;
}
// Same as ReceiveTimeout() but waits for as long as it takes for a message
// to become available (so it can't return wxMSGQUEUE_TIMEOUT)
wxMessageQueueError Receive(T& msg)
{
wxCHECK( IsOk(), wxMSGQUEUE_MISC_ERROR );
wxMutexLocker locker(m_mutex);
wxCHECK( locker.IsOk(), wxMSGQUEUE_MISC_ERROR );
while ( m_messages.empty() )
{
wxCondError result = m_conditionNotEmpty.Wait();
wxCHECK( result == wxCOND_NO_ERROR, wxMSGQUEUE_MISC_ERROR );
}
msg = m_messages.front();
m_messages.pop();
return wxMSGQUEUE_NO_ERROR;
}
// Return false only if there was a fatal error in ctor
bool IsOk() const
{
return m_conditionNotEmpty.IsOk();
}
private:
// Disable copy ctor and assignment operator
wxMessageQueue(const wxMessageQueue<T>& rhs);
wxMessageQueue<T>& operator=(const wxMessageQueue<T>& rhs);
mutable wxMutex m_mutex;
wxCondition m_conditionNotEmpty;
std::queue<T> m_messages;
};
#endif // wxUSE_THREADS
#endif // _WX_MSGQUEUE_H_