Separate event-related stuff from Base

[libs/core.git] / source / io / eventobject.h

diff --git a/source/io/eventobject.h b/source/io/eventobject.h
new file mode 100644 (file)
index 0000000..b8423c9
--- /dev/null
+++ b/source/io/eventobject.h
@@ -0,0 +1,54 @@
+#ifndef MSP_IO_EVENTOBJECT_H_
+#define MSP_IO_EVENTOBJECT_H_
+
+#include "base.h"
+
+namespace Msp {
+namespace IO {
+
+struct Handle;
+
+/**
+Interface class for objects that can provide event-based I/O.  These objects
+can be fed to the various poll functions in poll.h, or added to an
+EventDispatcher to generate event signals.
+*/
+class EventObject: public Base
+{
+public:
+       /** Emitted when there is data available for reading.  If all data is not
+       read, the signal is emitted again immediately. */
+       sigc::signal<void> signal_data_available;
+
+       /** Emitted when the mask of interesting events changes.  Mainly for use by
+       EventDispatcher. */
+       sigc::signal<void, PollEvent> signal_events_changed;
+
+private:
+       PollEvent events;
+
+protected:
+       EventObject();
+
+       void set_events(PollEvent);
+public:
+       /** Returns a mask of the currently interesting events.  Used by
+       EventDispatcher. */
+       PollEvent get_events() const { return events; }
+
+       /** Returns a handle for polling. */
+       virtual const Handle &get_event_handle() = 0;
+
+       /** Notifies the object of an event.  Used by EventDispatcher. */
+       void event(PollEvent);
+
+protected:
+       /** Called when an event occurs.  Derived classes can implement this to
+       process events. */
+       virtual void on_event(PollEvent) { }
+};
+
+} // namespace IO
+} // namespace Msp
+
+#endif