wxWidgets/include/wx/unix/private/executeiohandler.h
2017-02-24 23:37:44 +01:00

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///////////////////////////////////////////////////////////////////////////////
// Name: wx/unix/private/executeiohandler.h
// Purpose: IO handler class for the FD used by wxExecute() under Unix
// Author: Rob Bresalier, Vadim Zeitlin
// Created: 2013-01-06
// Copyright: (c) 2013 Rob Bresalier, Vadim Zeitlin
// Licence: wxWindows licence
///////////////////////////////////////////////////////////////////////////////
#ifndef _WX_UNIX_PRIVATE_EXECUTEIOHANDLER_H_
#define _WX_UNIX_PRIVATE_EXECUTEIOHANDLER_H_
#include "wx/private/streamtempinput.h"
// This class handles IO events on the pipe FD connected to the child process
// stdout/stderr and is used by wxExecute().
//
// Currently it can derive from either wxEventLoopSourceHandler or
// wxFDIOHandler depending on the kind of dispatcher/event loop it is used
// with. In the future, when we get rid of wxFDIOHandler entirely, it will
// derive from wxEventLoopSourceHandler only.
template <class T>
class wxExecuteIOHandlerBase : public T
{
public:
wxExecuteIOHandlerBase(int fd, wxStreamTempInputBuffer& buf)
: m_fd(fd),
m_buf(buf)
{
m_callbackDisabled = false;
}
// Called when the associated descriptor is available for reading.
virtual void OnReadWaiting() wxOVERRIDE
{
// Sync process, process all data coming at us from the pipe so that
// the pipe does not get full and cause a deadlock situation.
m_buf.Update();
if ( m_buf.Eof() )
DisableCallback();
}
// These methods are never called as we only monitor the associated FD for
// reading, but we still must implement them as they're pure virtual in the
// base class.
virtual void OnWriteWaiting() wxOVERRIDE { }
virtual void OnExceptionWaiting() wxOVERRIDE { }
// Disable any future calls to our OnReadWaiting(), can be called when
// we're sure that no more input is forthcoming.
void DisableCallback()
{
if ( !m_callbackDisabled )
{
m_callbackDisabled = true;
DoDisable();
}
}
protected:
const int m_fd;
private:
virtual void DoDisable() = 0;
wxStreamTempInputBuffer& m_buf;
// If true, DisableCallback() had been already called.
bool m_callbackDisabled;
wxDECLARE_NO_COPY_CLASS(wxExecuteIOHandlerBase);
};
// This is the version used with wxFDIODispatcher, which must be passed to the
// ctor in order to register this handler with it.
class wxExecuteFDIOHandler : public wxExecuteIOHandlerBase<wxFDIOHandler>
{
public:
wxExecuteFDIOHandler(wxFDIODispatcher& dispatcher,
int fd,
wxStreamTempInputBuffer& buf)
: wxExecuteIOHandlerBase<wxFDIOHandler>(fd, buf),
m_dispatcher(dispatcher)
{
dispatcher.RegisterFD(fd, this, wxFDIO_INPUT);
}
virtual ~wxExecuteFDIOHandler()
{
DisableCallback();
}
private:
virtual void DoDisable() wxOVERRIDE
{
m_dispatcher.UnregisterFD(m_fd);
}
wxFDIODispatcher& m_dispatcher;
wxDECLARE_NO_COPY_CLASS(wxExecuteFDIOHandler);
};
// And this is the version used with an event loop. As AddSourceForFD() is
// static, we don't require passing the event loop to the ctor but an event
// loop must be running to handle our events.
class wxExecuteEventLoopSourceHandler
: public wxExecuteIOHandlerBase<wxEventLoopSourceHandler>
{
public:
wxExecuteEventLoopSourceHandler(int fd, wxStreamTempInputBuffer& buf)
: wxExecuteIOHandlerBase<wxEventLoopSourceHandler>(fd, buf)
{
m_source = wxEventLoop::AddSourceForFD(fd, this, wxEVENT_SOURCE_INPUT);
}
virtual ~wxExecuteEventLoopSourceHandler()
{
DisableCallback();
}
private:
virtual void DoDisable() wxOVERRIDE
{
delete m_source;
m_source = NULL;
}
wxEventLoopSource* m_source;
wxDECLARE_NO_COPY_CLASS(wxExecuteEventLoopSourceHandler);
};
#endif // _WX_UNIX_PRIVATE_EXECUTEIOHANDLER_H_