#ifndef _WX_EVTLOOP_H_
#define _WX_EVTLOOP_H_
+#include "wx/event.h"
#include "wx/utils.h"
+/*
+ NOTE ABOUT wxEventLoopBase::YieldFor LOGIC
+ ------------------------------------------
+
+ The YieldFor() function helps to avoid re-entrancy problems and problems
+ caused by out-of-order event processing
+ (see "wxYield-like problems" and "wxProgressDialog+threading BUG" wx-dev threads).
+
+ The logic behind YieldFor() is simple: it analyzes the queue of the native
+ events generated by the underlying GUI toolkit and picks out and processes
+ only those matching the given mask.
+
+ It's important to note that YieldFor() is used to selectively process the
+ events generated by the NATIVE toolkit.
+ Events syntethized by wxWidgets code or by user code are instead selectively
+ processed thanks to the logic built into wxEvtHandler::ProcessPendingEvents().
+ In fact, when wxEvtHandler::ProcessPendingEvents gets called from inside a
+ YieldFor() call, wxEventLoopBase::IsEventAllowedInsideYield is used to decide
+ if the pending events for that event handler can be processed.
+ If all the pending events associated with that event handler result as "not processable",
+ the event handler "delays" itself calling wxEventLoopBase::DelayPendingEventHandler
+ (so it's moved: m_handlersWithPendingEvents => m_handlersWithPendingDelayedEvents).
+ Last, wxEventLoopBase::ProcessPendingEvents() before exiting moves the delayed
+ event handlers back into the list of handlers with pending events
+ (m_handlersWithPendingDelayedEvents => m_handlersWithPendingEvents) so that
+ a later call to ProcessPendingEvents() (possibly outside the YieldFor() call)
+ will process all pending events as usual.
+*/
+
// ----------------------------------------------------------------------------
// wxEventLoopBase: interface for wxEventLoop
// ----------------------------------------------------------------------------
{
public:
// trivial, but needed (because of wxEventLoopBase) ctor
- wxEventLoopBase() { }
+ wxEventLoopBase();
// dtor
virtual ~wxEventLoopBase() { }
// using it
virtual bool IsOk() const { return true; }
+ // returns true if this is the main loop
+ bool IsMain() const;
+
+
+ // dispatch&processing
+ // -------------------
// start the event loop, return the exit code when it is finished
virtual int Run() = 0;
+ // is this event loop running now?
+ //
+ // notice that even if this event loop hasn't terminated yet but has just
+ // spawned a nested (e.g. modal) event loop, this would return false
+ bool IsRunning() const;
+
// exit from the loop with the given exit code
virtual void Exit(int rc = 0) = 0;
// exit the loop or -1 if timeout expired
virtual int DispatchTimeout(unsigned long timeout) = 0;
+ // implement this to wake up the loop: usually done by posting a dummy event
+ // to it (can be called from non main thread)
+ virtual void WakeUp() = 0;
+
+
+ // idle handling
+ // -------------
+
+ // make sure that idle events are sent again
+ virtual void WakeUpIdle();
+
+ // this virtual function is called when the application
+ // becomes idle and by default it forwards to wxApp::ProcessIdle() and
+ // while it can be overridden in a custom event loop, you must call the
+ // base class version to ensure that idle events are still generated
+ //
+ // it should return true if more idle events are needed, false if not
+ virtual bool ProcessIdle();
+
+
+ // Yield-related hooks
+ // -------------------
+
+ // process all currently pending events right now
+ //
+ // it is an error to call Yield() recursively unless the value of
+ // onlyIfNeeded is true
+ //
+ // WARNING: this function is dangerous as it can lead to unexpected
+ // reentrancies (i.e. when called from an event handler it
+ // may result in calling the same event handler again), use
+ // with _extreme_ care or, better, don't use at all!
+ bool Yield(bool onlyIfNeeded = false);
+ virtual bool YieldFor(long eventsToProcess) = 0;
+
+ // returns true if the main thread is inside a Yield() call
+ virtual bool IsYielding() const
+ { return m_isInsideYield; }
+
+ // returns true if events of the given event category should be immediately
+ // processed inside a wxApp::Yield() call or rather should be queued for
+ // later processing by the main event loop
+ virtual bool IsEventAllowedInsideYield(wxEventCategory cat) const
+ { return (m_eventsToProcessInsideYield & cat) != 0; }
+
+ // no SafeYield hooks since it uses wxWindow which is not available when wxUSE_GUI=0
+
+
+ // active loop
+ // -----------
// return currently active (running) event loop, may be NULL
static wxEventLoopBase *GetActive() { return ms_activeLoop; }
// set currently active (running) event loop
- static void SetActive(wxEventLoopBase* loop) { ms_activeLoop = loop; }
+ static void SetActive(wxEventLoopBase* loop);
- // is this event loop running now?
- //
- // notice that even if this event loop hasn't terminated yet but has just
- // spawned a nested (e.g. modal) event loop, this would return false
- bool IsRunning() const;
-
- // implement this to wake up the loop: usually done by posting a dummy event
- // to it (can be called from non main thread)
- virtual void WakeUp() = 0;
protected:
// this function should be called before the event loop terminates, whether
// this happens normally (because of Exit() call) or abnormally (because of
// an exception thrown from inside the loop)
- virtual void OnExit() { }
-
+ virtual void OnExit();
// the pointer to currently active loop
static wxEventLoopBase *ms_activeLoop;
- DECLARE_NO_COPY_CLASS(wxEventLoopBase)
+ // YieldFor() helpers:
+ bool m_isInsideYield;
+ long m_eventsToProcessInsideYield;
+
+ wxDECLARE_NO_COPY_CLASS(wxEventLoopBase);
};
#if defined(__WXMSW__) || defined(__WXMAC__) || defined(__WXDFB__) || defined(__UNIX__)
// should we exit the loop?
bool m_shouldExit;
+
+private:
+ // process all already pending events and dispatch a new one (blocking
+ // until it appears in the event queue if necessary)
+ //
+ // returns the return value of Dispatch()
+ bool ProcessEvents();
+
+ wxDECLARE_NO_COPY_CLASS(wxEventLoopManual);
};
#endif // platforms using "manual" loop
#include "wx/msw/evtloop.h"
#elif defined(__WXMAC__)
#include "wx/osx/evtloop.h"
+#elif defined(__WXCOCOA__)
+ #include "wx/cocoa/evtloop.h"
#elif defined(__WXDFB__)
#include "wx/dfb/evtloop.h"
#elif defined(__WXGTK20__)
}
}
virtual void WakeUp() { }
+ virtual bool YieldFor(long eventsToProcess);
protected:
// the pointer to the port specific implementation class
wxEventLoopImpl *m_impl;
- DECLARE_NO_COPY_CLASS(wxGUIEventLoop)
+ wxDECLARE_NO_COPY_CLASS(wxGUIEventLoop);
};
#endif // platforms
projects / wxWidgets.git / blobdiff