Move PBD::canonical_path to pbd/file_utils.h/cc and reimplement for Windows

[ardour.git] / libs / pbd / pbd / crossthread.h

diff --git a/libs/pbd/pbd/crossthread.h b/libs/pbd/pbd/crossthread.h
index f16cab94053c9a5594391195036c0449452524a8..e87879e4a31bb9a36698b1f71cc9548919be8c43 100644 (file)
--- a/libs/pbd/pbd/crossthread.h
+++ b/libs/pbd/pbd/crossthread.h
@@ -1,5 +1,5 @@
 /*
-    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
@@ -26,36 +26,83 @@
 
 #include <glibmm/main.h>
 
-class CrossThreadChannel { 
-  public:
-       CrossThreadChannel();
+#include "pbd/libpbd_visibility.h"
+
+#ifdef PLATFORM_WINDOWS
+#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.
+ *
+ * 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.
+ */
+
+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();
-       int selectable() const { return fds[0]; }
 
-        int deliver (char msg);
-        int receive (char& msg);
-        
+       /* 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
+        * two mechanisms should not be used on the same CrossThreadChannel
+        * because there is no way to know which byte value will be used
+        * for ::wakeup()
+        */
+       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, bool wait = false);
+
+       /** empty the channel of all requests.
+        * 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"
+        * in the channel will not be important.
+        */
        void drain ();
-       static void drain (int fd);
 
-       /* glibmm 2.22 and earlier has a terrifying bug that will
-          cause crashes whenever a Source is removed from
-          a MainContext (including the destruction of the MainContext),
-          because the Source is destroyed "out from under the nose of" 
-          the RefPtr. I (Paul) have fixed this (https://bugzilla.gnome.org/show_bug.cgi?id=561885)
-          but in the meantime, we need a hack to get around the issue.
-       */
+       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;
 
-       Glib::RefPtr<Glib::IOSource> ios();
-       void drop_ios ();
+       bool poll_for_request();
 
-       bool ok() const { return fds[0] >= 0 && fds[1] >= 0; }
+#ifndef PLATFORM_WINDOWS
+       int fds[2]; // current implementation uses a pipe/fifo
+#else
+
+       SOCKET send_socket;
+       SOCKET receive_socket;
+       struct sockaddr_in recv_address;
+#endif
 
-  private:
-       Glib::RefPtr<Glib::IOSource>* _ios; // lazily constructed
-       int fds[2];
 };
 
 #endif /* __pbd__crossthread_h__ */