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+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is mozilla.org Code.
+ *
+ * The Initial Developer of the Original Code is
+ * Netscape Communications Corporation.
+ * Portions created by the Initial Developer are Copyright (C) 1998
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either of the GNU General Public License Version 2 or later (the "GPL"),
+ * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+/**********************************************************************
+NSPL Events
+
+Defining Events
+---------------
+
+Events are essentially structures that represent argument lists for a
+function that will run on another thread. All event structures you
+define must include a PLEvent struct as their first field:
+
+ typedef struct MyEventType {
+ PLEvent e;
+ // arguments follow...
+ int x;
+ char* y;
+ } MyEventType;
+
+It is also essential that you establish a model of ownership for each
+argument passed in an event record, i.e. whether particular arguments
+will be deleted by the event destruction callback, or whether they
+only loaned to the event handler callback, and guaranteed to persist
+until the time at which the handler is called.
+
+Sending Events
+--------------
+
+Events are initialized by PL_InitEvent and can be sent via
+PL_PostEvent or PL_PostSynchronousEvent. Events can also have an
+owner. The owner of an event can revoke all the events in a given
+event-queue by calling PL_RevokeEvents. An owner might want
+to do this if, for instance, it is being destroyed, and handling the
+events after the owner's destruction would cause an error (e.g. an
+MWContext).
+
+Since the act of initializing and posting an event must be coordinated
+with it's possible revocation, it is essential that the event-queue's
+monitor be entered surrounding the code that constructs, initializes
+and posts the event:
+
+ void postMyEvent(MyOwner* owner, int x, char* y)
+ {
+ MyEventType* event;
+
+ PL_ENTER_EVENT_QUEUE_MONITOR(myQueue);
+
+ // construct
+ event = PR_NEW(MyEventType);
+ if (event == NULL) goto done;
+
+ // initialize
+ PL_InitEvent(event, owner,
+ (PLHandleEventProc)handleMyEvent,
+ (PLDestroyEventProc)destroyMyEvent);
+ event->x = x;
+ event->y = strdup(y);
+
+ // post
+ PL_PostEvent(myQueue, &event->e);
+
+ done:
+ PL_EXIT_EVENT_QUEUE_MONITOR(myQueue);
+ }
+
+If you don't call PL_InitEvent and PL_PostEvent within the
+event-queue's monitor, you'll get a big red assert.
+
+Handling Events
+---------------
+
+To handle an event you must write a callback that is passed the event
+record you defined containing the event's arguments:
+
+ void* handleMyEvent(MyEventType* event)
+ {
+ doit(event->x, event->y);
+ return NULL; // you could return a value for a sync event
+ }
+
+Similarly for the destruction callback:
+
+ void destroyMyEvent(MyEventType* event)
+ {
+ free(event->y); // created by strdup
+ free(event);
+ }
+
+Processing Events in Your Event Loop
+------------------------------------
+
+If your main loop only processes events delivered to the event queue,
+things are rather simple. You just get the next event (which may
+block), and then handle it:
+
+ while (1) {
+ event = PL_GetEvent(myQueue);
+ PL_HandleEvent(event);
+ }
+
+However, if other things must be waited on, you'll need to obtain a
+file-descriptor that represents your event queue, and hand it to select:
+
+ fd = PL_GetEventQueueSelectFD(myQueue);
+ ...add fd to select set...
+ while (select(...)) {
+ if (...fd...) {
+ PL_ProcessPendingEvents(myQueue);
+ }
+ ...
+ }
+
+Of course, with Motif and Windows it's more complicated than that, and
+on Mac it's completely different, but you get the picture.
+
+Revoking Events
+---------------
+If at any time an owner of events is about to be destroyed, you must
+take steps to ensure that no one tries to use the event queue after
+the owner is gone (or a crash may result). You can do this by either
+processing all the events in the queue before destroying the owner:
+
+ {
+ ...
+ PL_ENTER_EVENT_QUEUE_MONITOR(myQueue);
+ PL_ProcessPendingEvents(myQueue);
+ DestroyMyOwner(owner);
+ PL_EXIT_EVENT_QUEUE_MONITOR(myQueue);
+ ...
+ }
+
+or by revoking the events that are in the queue for that owner. This
+removes them from the queue and calls their destruction callback:
+
+ {
+ ...
+ PL_ENTER_EVENT_QUEUE_MONITOR(myQueue);
+ PL_RevokeEvents(myQueue, owner);
+ DestroyMyOwner(owner);
+ PL_EXIT_EVENT_QUEUE_MONITOR(myQueue);
+ ...
+ }
+
+In either case it is essential that you be in the event-queue's monitor
+to ensure that all events are removed from the queue for that owner,
+and to ensure that no more events will be delivered for that owner.
+**********************************************************************/
+
+#ifndef plevent_h___
+#define plevent_h___
+
+#include "prtypes.h"
+#include "prclist.h"
+#include "prthread.h"
+#include "prlock.h"
+#include "prcvar.h"
+#include "prmon.h"
+
+/* For HWND */
+#if defined(XP_WIN32)
+#include <windef.h>
+#elif defined(XP_OS2)
+#define INCL_DOSMISC
+#define INCL_DOSPROCESS
+#define INCL_DOSERRORS
+#include <os2.h>
+#endif
+
+#ifdef VBOX_WITH_XPCOM_NAMESPACE_CLEANUP
+#define PL_DestroyEvent VBoxNsplPL_DestroyEvent
+#define PL_HandleEvent VBoxNsplPL_HandleEvent
+#define PL_InitEvent VBoxNsplPL_InitEvent
+#define PL_CreateEventQueue VBoxNsplPL_CreateEventQueue
+#define PL_CreateMonitoredEventQueue VBoxNsplPL_CreateMonitoredEventQueue
+#define PL_CreateNativeEventQueue VBoxNsplPL_CreateNativeEventQueue
+#define PL_DequeueEvent VBoxNsplPL_DequeueEvent
+#define PL_DestroyEventQueue VBoxNsplPL_DestroyEventQueue
+#define PL_EventAvailable VBoxNsplPL_EventAvailable
+#define PL_EventLoop VBoxNsplPL_EventLoop
+#define PL_GetEvent VBoxNsplPL_GetEvent
+#define PL_GetEventOwner VBoxNsplPL_GetEventOwner
+#define PL_GetEventQueueMonitor VBoxNsplPL_GetEventQueueMonitor
+#define PL_GetEventQueueSelectFD VBoxNsplPL_GetEventQueueSelectFD
+#define PL_MapEvents VBoxNsplPL_MapEvents
+#define PL_PostEvent VBoxNsplPL_PostEvent
+#define PL_PostSynchronousEvent VBoxNsplPL_PostSynchronousEvent
+#define PL_ProcessEventsBeforeID VBoxNsplPL_ProcessEventsBeforeID
+#define PL_ProcessPendingEvents VBoxNsplPL_ProcessPendingEvents
+#define PL_RegisterEventIDFunc VBoxNsplPL_RegisterEventIDFunc
+#define PL_RevokeEvents VBoxNsplPL_RevokeEvents
+#define PL_UnregisterEventIDFunc VBoxNsplPL_UnregisterEventIDFunc
+#define PL_WaitForEvent VBoxNsplPL_WaitForEvent
+#define PL_IsQueueNative VBoxNsplPL_IsQueueNative
+#define PL_IsQueueOnCurrentThread VBoxNsplPL_IsQueueOnCurrentThread
+#define PL_FavorPerformanceHint VBoxNsplPL_FavorPerformanceHint
+#endif /* VBOX_WITH_XPCOM_NAMESPACE_CLEANUP */
+
+PR_BEGIN_EXTERN_C
+
+/* Typedefs */
+
+typedef struct PLEvent PLEvent;
+typedef struct PLEventQueue PLEventQueue;
+
+/*******************************************************************************
+ * Event Queue Operations
+ ******************************************************************************/
+
+/*
+** Creates a new event queue. Returns NULL on failure.
+*/
+PR_EXTERN(PLEventQueue*)
+PL_CreateEventQueue(const char* name, PRThread* handlerThread);
+
+
+/* -----------------------------------------------------------------------
+** FUNCTION: PL_CreateNativeEventQueue()
+**
+** DESCRIPTION:
+** PL_CreateNativeEventQueue() creates an event queue that
+** uses platform specific notify mechanisms.
+**
+** For Unix, the platform specific notify mechanism provides
+** an FD that may be extracted using the function
+** PL_GetEventQueueSelectFD(). The FD returned may be used in
+** a select() function call.
+**
+** For Windows, the platform specific notify mechanism
+** provides an event receiver window that is called by
+** Windows to process the event using the windows message
+** pump engine.
+**
+** INPUTS:
+** name: A name, as a diagnostic aid.
+**
+** handlerThread: A pointer to the PRThread structure for
+** the thread that will "handle" events posted to this event
+** queue.
+**
+** RETURNS:
+** A pointer to a PLEventQueue structure or NULL.
+**
+*/
+PR_EXTERN(PLEventQueue *)
+ PL_CreateNativeEventQueue(
+ const char *name,
+ PRThread *handlerThread
+ );
+
+/* -----------------------------------------------------------------------
+** FUNCTION: PL_CreateMonitoredEventQueue()
+**
+** DESCRIPTION:
+** PL_CreateMonitoredEventQueue() creates an event queue. No
+** platform specific notify mechanism is created with the
+** event queue.
+**
+** Users of this type of event queue must explicitly poll the
+** event queue to retreive and process events.
+**
+**
+** INPUTS:
+** name: A name, as a diagnostic aid.
+**
+** handlerThread: A pointer to the PRThread structure for
+** the thread that will "handle" events posted to this event
+** queue.
+**
+** RETURNS:
+** A pointer to a PLEventQueue structure or NULL.
+**
+*/
+PR_EXTERN(PLEventQueue *)
+ PL_CreateMonitoredEventQueue(
+ const char *name,
+ PRThread *handlerThread
+ );
+
+/*
+** Destroys an event queue.
+*/
+PR_EXTERN(void)
+PL_DestroyEventQueue(PLEventQueue* self);
+
+/*
+** Returns the monitor associated with an event queue. This monitor is
+** selectable. The monitor should be entered to protect against anyone
+** calling PL_RevokeEvents while the event is trying to be constructed
+** and delivered.
+*/
+PR_EXTERN(PRMonitor*)
+PL_GetEventQueueMonitor(PLEventQueue* self);
+
+#define PL_ENTER_EVENT_QUEUE_MONITOR(queue) \
+ PR_EnterMonitor(PL_GetEventQueueMonitor(queue))
+
+#define PL_EXIT_EVENT_QUEUE_MONITOR(queue) \
+ PR_ExitMonitor(PL_GetEventQueueMonitor(queue))
+
+/*
+** Posts an event to an event queue, waking up any threads waiting for an
+** event. If event is NULL, notification still occurs, but no event will
+** be available.
+**
+** Any events delivered by this routine will be destroyed by PL_HandleEvent
+** when it is called (by the event-handling thread).
+*/
+PR_EXTERN(PRStatus)
+PL_PostEvent(PLEventQueue* self, PLEvent* event);
+
+/*
+** Like PL_PostEvent, this routine posts an event to the event handling
+** thread, but does so synchronously, waiting for the result. The result
+** which is the value of the handler routine is returned.
+**
+** Any events delivered by this routine will be not be destroyed by
+** PL_HandleEvent, but instead will be destroyed just before the result is
+** returned (by the current thread).
+*/
+PR_EXTERN(void*)
+PL_PostSynchronousEvent(PLEventQueue* self, PLEvent* event);
+
+/*
+** Gets an event from an event queue. Returns NULL if no event is
+** available.
+*/
+PR_EXTERN(PLEvent*)
+PL_GetEvent(PLEventQueue* self);
+
+/*
+** Returns true if there is an event available for PL_GetEvent.
+*/
+PR_EXTERN(PRBool)
+PL_EventAvailable(PLEventQueue* self);
+
+/*
+** This is the type of the function that must be passed to PL_MapEvents
+** (see description below).
+*/
+typedef void
+(PR_CALLBACK *PLEventFunProc)(PLEvent* event, void* data, PLEventQueue* queue);
+
+/*
+** Applies a function to every event in the event queue. This can be used
+** to selectively handle, filter, or remove events. The data pointer is
+** passed to each invocation of the function fun.
+*/
+PR_EXTERN(void)
+PL_MapEvents(PLEventQueue* self, PLEventFunProc fun, void* data);
+
+/*
+** This routine walks an event queue and destroys any event whose owner is
+** the owner specified. The == operation is used to compare owners.
+*/
+PR_EXTERN(void)
+PL_RevokeEvents(PLEventQueue* self, void* owner);
+
+/*
+** This routine processes all pending events in the event queue. It can be
+** called from the thread's main event-processing loop whenever the event
+** queue's selectFD is ready (returned by PL_GetEventQueueSelectFD).
+*/
+PR_EXTERN(void)
+PL_ProcessPendingEvents(PLEventQueue* self);
+
+/*******************************************************************************
+ * Pure Event Queues
+ *
+ * For when you're only processing PLEvents and there is no native
+ * select, thread messages, or AppleEvents.
+ ******************************************************************************/
+
+/*
+** Blocks until an event can be returned from the event queue. This routine
+** may return NULL if the current thread is interrupted.
+*/
+PR_EXTERN(PLEvent*)
+PL_WaitForEvent(PLEventQueue* self);
+
+/*
+** One stop shopping if all you're going to do is process PLEvents. Just
+** call this and it loops forever processing events as they arrive. It will
+** terminate when your thread is interrupted or dies.
+*/
+PR_EXTERN(void)
+PL_EventLoop(PLEventQueue* self);
+
+/*******************************************************************************
+ * Native Event Queues
+ *
+ * For when you need to call select, or WaitNextEvent, and yet also want
+ * to handle PLEvents.
+ ******************************************************************************/
+
+/*
+** This routine allows you to grab the file descriptor associated with an
+** event queue and use it in the readFD set of select. Useful for platforms
+** that support select, and must wait on other things besides just PLEvents.
+*/
+PR_EXTERN(PRInt32)
+PL_GetEventQueueSelectFD(PLEventQueue* self);
+
+/*
+** This routine will allow you to check to see if the given eventQueue in
+** on the current thread. It will return PR_TRUE if so, else it will return
+** PR_FALSE
+*/
+PR_EXTERN(PRBool)
+ PL_IsQueueOnCurrentThread( PLEventQueue *queue );
+
+/*
+** Returns whether the queue is native (true) or monitored (false)
+*/
+PR_EXTERN(PRBool)
+PL_IsQueueNative(PLEventQueue *queue);
+
+/*******************************************************************************
+ * Event Operations
+ ******************************************************************************/
+
+/*
+** The type of an event handler function. This function is passed as an
+** initialization argument to PL_InitEvent, and called by
+** PL_HandleEvent. If the event is called synchronously, a void* result
+** may be returned (otherwise any result will be ignored).
+*/
+typedef void*
+(PR_CALLBACK *PLHandleEventProc)(PLEvent* self);
+
+/*
+** The type of an event destructor function. This function is passed as
+** an initialization argument to PL_InitEvent, and called by
+** PL_DestroyEvent.
+*/
+typedef void
+(PR_CALLBACK *PLDestroyEventProc)(PLEvent* self);
+
+/*
+** Initializes an event. Usually events are embedded in a larger event
+** structure which holds event-specific data, so this is an initializer
+** for that embedded part of the structure.
+*/
+PR_EXTERN(void)
+PL_InitEvent(PLEvent* self, void* owner,
+ PLHandleEventProc handler,
+ PLDestroyEventProc destructor);
+
+/*
+** Returns the owner of an event.
+*/
+PR_EXTERN(void*)
+PL_GetEventOwner(PLEvent* self);
+
+/*
+** Handles an event, calling the event's handler routine.
+*/
+PR_EXTERN(void)
+PL_HandleEvent(PLEvent* self);
+
+/*
+** Destroys an event, calling the event's destructor.
+*/
+PR_EXTERN(void)
+PL_DestroyEvent(PLEvent* self);
+
+/*
+** Removes an event from an event queue.
+*/
+PR_EXTERN(void)
+PL_DequeueEvent(PLEvent* self, PLEventQueue* queue);
+
+
+/*
+ * Give hint to native PL_Event notification mechanism. If the native
+ * platform needs to tradeoff performance vs. native event starvation
+ * this hint tells the native dispatch code which to favor.
+ * The default is to prevent event starvation.
+ *
+ * Calls to this function may be nested. When the number of calls that
+ * pass PR_TRUE is subtracted from the number of calls that pass PR_FALSE
+ * is greater than 0, performance is given precedence over preventing
+ * event starvation.
+ *
+ * The starvationDelay arg is only used when
+ * favorPerformanceOverEventStarvation is PR_FALSE. It is the
+ * amount of time in milliseconds to wait before the PR_FALSE actually
+ * takes effect.
+ */
+PR_EXTERN(void)
+PL_FavorPerformanceHint(PRBool favorPerformanceOverEventStarvation, PRUint32 starvationDelay);
+
+
+/*******************************************************************************
+ * Private Stuff
+ ******************************************************************************/
+
+struct PLEvent {
+ PRCList link;
+ PLHandleEventProc handler;
+ PLDestroyEventProc destructor;
+ void* owner;
+ void* synchronousResult;
+ PRLock* lock;
+ PRCondVar* condVar;
+ PRBool handled;
+#ifdef PL_POST_TIMINGS
+ PRIntervalTime postTime;
+#endif
+#ifdef XP_UNIX
+ unsigned long id;
+#endif /* XP_UNIX */
+ /* other fields follow... */
+};
+
+/******************************************************************************/
+
+/*
+** Returns the event queue associated with the main thread.
+**
+*/
+#if defined(XP_WIN) || defined(XP_OS2)
+/* -----------------------------------------------------------------------
+** FUNCTION: PL_GetNativeEventReceiverWindow()
+**
+** DESCRIPTION:
+** PL_GetNativeEventReceiverWindow() returns the windows
+** handle of the event receiver window associated with the
+** referenced PLEventQueue argument.
+**
+** INPUTS:
+** PLEventQueue pointer
+**
+** RETURNS:
+** event receiver window handle.
+**
+** RESTRICTIONS: MS-Windows ONLY.
+**
+*/
+PR_EXTERN(HWND)
+ PL_GetNativeEventReceiverWindow(
+ PLEventQueue *eqp
+ );
+#endif /* XP_WIN || XP_OS2 */
+
+#ifdef XP_UNIX
+/* -----------------------------------------------------------------------
+** FUNCTION: PL_ProcessEventsBeforeID()
+**
+** DESCRIPTION:
+**
+** PL_ProcessEventsBeforeID() will process events in a native event
+** queue that have an id that is older than the ID passed in.
+**
+** INPUTS:
+** PLEventQueue *aSelf
+** unsigned long aID
+**
+** RETURNS:
+** PRInt32 number of requests processed, -1 on error.
+**
+** RESTRICTIONS: Unix only (well, X based unix only)
+*/
+PR_EXTERN(PRInt32)
+PL_ProcessEventsBeforeID(PLEventQueue *aSelf, unsigned long aID);
+
+/* This prototype is a function that can be called when an event is
+ posted to stick an ID on it. */
+
+typedef unsigned long
+(PR_CALLBACK *PLGetEventIDFunc)(void *aClosure);
+
+
+/* -----------------------------------------------------------------------
+** FUNCTION: PL_RegisterEventIDFunc()
+**
+** DESCRIPTION:
+**
+** This function registers a function for getting the ID on unix for
+** this event queue.
+**
+** INPUTS:
+** PLEventQueue *aSelf
+** PLGetEventIDFunc func
+** void *aClosure
+**
+** RETURNS:
+** void
+**
+** RESTRICTIONS: Unix only (well, X based unix only) */
+PR_EXTERN(void)
+PL_RegisterEventIDFunc(PLEventQueue *aSelf, PLGetEventIDFunc aFunc,
+ void *aClosure);
+
+/* -----------------------------------------------------------------------
+** FUNCTION: PL_RegisterEventIDFunc()
+**
+** DESCRIPTION:
+**
+** This function unregisters a function for getting the ID on unix for
+** this event queue.
+**
+** INPUTS:
+** PLEventQueue *aSelf
+**
+** RETURNS:
+** void
+**
+** RESTRICTIONS: Unix only (well, X based unix only) */
+PR_EXTERN(void)
+PL_UnregisterEventIDFunc(PLEventQueue *aSelf);
+
+#endif /* XP_UNIX */
+
+
+/* ----------------------------------------------------------------------- */
+
+#if defined(NO_NSPR_10_SUPPORT)
+#else
+/********* ???????????????? FIX ME ??????????????????????????? *****/
+/********************** Some old definitions *****************************/
+
+/* Re: prevent.h->plevent.h */
+#define PREvent PLEvent
+#define PREventQueue PLEventQueue
+#define PR_CreateEventQueue PL_CreateEventQueue
+#define PR_DestroyEventQueue PL_DestroyEventQueue
+#define PR_GetEventQueueMonitor PL_GetEventQueueMonitor
+#define PR_ENTER_EVENT_QUEUE_MONITOR PL_ENTER_EVENT_QUEUE_MONITOR
+#define PR_EXIT_EVENT_QUEUE_MONITOR PL_EXIT_EVENT_QUEUE_MONITOR
+#define PR_PostEvent PL_PostEvent
+#define PR_PostSynchronousEvent PL_PostSynchronousEvent
+#define PR_GetEvent PL_GetEvent
+#define PR_EventAvailable PL_EventAvailable
+#define PREventFunProc PLEventFunProc
+#define PR_MapEvents PL_MapEvents
+#define PR_RevokeEvents PL_RevokeEvents
+#define PR_ProcessPendingEvents PL_ProcessPendingEvents
+#define PR_WaitForEvent PL_WaitForEvent
+#define PR_EventLoop PL_EventLoop
+#define PR_GetEventQueueSelectFD PL_GetEventQueueSelectFD
+#define PRHandleEventProc PLHandleEventProc
+#define PRDestroyEventProc PLDestroyEventProc
+#define PR_InitEvent PL_InitEvent
+#define PR_GetEventOwner PL_GetEventOwner
+#define PR_HandleEvent PL_HandleEvent
+#define PR_DestroyEvent PL_DestroyEvent
+#define PR_DequeueEvent PL_DequeueEvent
+#define PR_GetMainEventQueue PL_GetMainEventQueue
+
+/********* ????????????? End Fix me ?????????????????????????????? *****/
+#endif /* NO_NSPR_10_SUPPORT */
+
+PR_END_EXTERN_C
+
+#endif /* plevent_h___ */