/*
- Copyright (C) 2000-2007 Paul Davis
+ Copyright (C) 2000-2007 Paul Davis
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
#include "pbd/libpbd_visibility.h"
#ifdef PLATFORM_WINDOWS
-#include <Windows.h>
+#include <windows.h>
#endif // PLATFORM_WINDOWS
/** A simple abstraction of a mechanism of signalling one thread from another.
* The signaller calls ::wakeup() to tell the signalled thread to check for
- * work to be done.
+ * work to be done.
*
* This implementation provides both ::selectable() for use in direct
* poll/select-based event loops, and a Glib::IOSource via ::ios() for use
- * in Glib main loop based situations.
+ * in Glib main loop based situations.
*/
-class LIBPBD_API CrossThreadChannel {
- public:
+class LIBPBD_API CrossThreadChannel {
+public:
/** if @a non_blocking is true, the channel will not cause blocking
* when used in an event loop based on poll/select or the glib main
* loop.
*/
CrossThreadChannel(bool non_blocking);
~CrossThreadChannel();
-
+
/** Tell the listening thread that is has work to do.
*/
void wakeup();
-
+
/* if the listening thread cares about the precise message
* it is being sent, then ::deliver() can be used to send
* a single byte message rather than a simple wakeup. These
* because there is no way to know which byte value will be used
* for ::wakeup()
*/
- int deliver (char msg);
+ int deliver (char msg);
/** if using ::deliver() to wakeup the listening thread, then
* the listener should call ::receive() to fetch the message
* type from the channel.
+ *
+ * wait = true only make sense for non_blocking channels,
+ * it polls for data to become available.
*/
- int receive (char& msg);
+ int receive (char& msg, bool wait = false);
/** empty the channel of all requests.
- * Typically this is done as soon as input
+ * Typically this is done as soon as input
* is noticed on the channel, because the
* handler will look at a separately managed work
* queue. The actual number of queued "wakeups"
*/
void drain ();
- void set_receive_handler (sigc::slot<bool,Glib::IOCondition> s);
- void attach (Glib::RefPtr<Glib::MainContext>);
+ void set_receive_handler (sigc::slot<bool,Glib::IOCondition> s);
+ void attach (Glib::RefPtr<Glib::MainContext>);
private:
friend gboolean cross_thread_channel_call_receive_slot (GIOChannel*, GIOCondition condition, void *data);
GIOChannel* receive_channel;
- GSource* receive_source;
- sigc::slot<bool,Glib::IOCondition> receive_slot;
+ GSource* receive_source;
+ sigc::slot<bool,Glib::IOCondition> receive_slot;
+
+ bool poll_for_request();
#ifndef PLATFORM_WINDOWS
int fds[2]; // current implementation uses a pipe/fifo