Adding upstream version 6.1.22-dfsg.upstream/6.1.22-dfsgupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1774 insertions, 0 deletions

diff --git a/src/libs/xpcom18a4/xpcom/threads/plevent.c b/src/libs/xpcom18a4/xpcom/threads/plevent.c
new file mode 100644
index 00000000..c5e9040f
--- /dev/null
+++ b/src/libs/xpcom18a4/xpcom/threads/plevent.c
@@ -0,0 +1,1774 @@
+/* -*- 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 ***** */
+
+#if defined(_WIN32)
+#include <windows.h>
+#endif
+
+#if defined(XP_OS2)
+#define INCL_DOS
+#define INCL_DOSERRORS
+#define INCL_WIN
+#include <os2.h>
+#define DefWindowProc WinDefWindowProc
+#endif /* XP_OS2 */
+
+#include "nspr.h"
+#include "plevent.h"
+
+#if !defined(WIN32)
+#include <errno.h>
+#include <stddef.h>
+#if !defined(XP_OS2)
+#include <unistd.h>
+#endif /* !XP_OS2 */
+#endif /* !Win32 */
+
+#if defined(XP_UNIX)
+/* for fcntl */
+#include <sys/types.h>
+#include <fcntl.h>
+#endif
+
+#if defined(XP_BEOS)
+#include <kernel/OS.h>
+#endif
+
+#if defined(XP_MACOSX)
+#if defined(MOZ_WIDGET_COCOA)
+#include <CoreFoundation/CoreFoundation.h>
+#define MAC_USE_CFRUNLOOPSOURCE
+#elif defined(TARGET_CARBON)
+/* #include <CarbonEvents.h> */
+/* #define MAC_USE_CARBON_EVENT */
+#include <CoreFoundation/CoreFoundation.h>
+#define MAC_USE_CFRUNLOOPSOURCE
+#endif
+#endif
+
+#include "private/pprthred.h"
+
+#if defined(VMS)
+/*
+** On OpenVMS, XtAppAddInput doesn't want a regular fd, instead it
+** wants an event flag. So, we don't create and use a pipe for
+** notification of when an event queue has something ready, instead
+** we use an event flag. Shouldn't be a problem if we only have
+** a few event queues.
+*/
+#include <lib$routines.h>
+#include <starlet.h>
+#include <stsdef.h>
+#endif /* VMS */
+
+#if defined(_WIN32)
+/* Comment out the following USE_TIMER define to prevent
+ * WIN32 from using a WIN32 native timer for PLEvent notification.
+ * With USE_TIMER defined we will use a timer when pending input
+ * or paint events are starved, otherwise it will use a posted
+ * WM_APP msg for PLEvent notification.
+ */
+#define USE_TIMER
+
+/* Threshold defined in milliseconds for determining when the input
+ * and paint events have been held in the WIN32 msg queue too long
+ */
+#define INPUT_STARVATION_LIMIT    50
+/* The paint starvation limit is set to the smallest value which
+ * does not cause performance degradation while running page load tests
+ */
+#define PAINT_STARVATION_LIMIT   750
+/* The WIN9X paint starvation limit is larger because it was
+ * determined that the following value was required to prevent performance
+ * degradation on page load tests for WIN98/95 only.
+ */
+#define WIN9X_PAINT_STARVATION_LIMIT 3000
+
+#define TIMER_ID 0
+/* If _md_PerformanceSetting <=0 then no event starvation otherwise events will be starved */
+static PRInt32  _md_PerformanceSetting = 0;
+static PRUint32 _md_StarvationDelay    = 0;
+static PRUint32 _md_SwitchTime         = 0;
+#endif
+
+static PRLogModuleInfo *event_lm = NULL;
+
+/*******************************************************************************
+ * Private Stuff
+ ******************************************************************************/
+
+/*
+** EventQueueType -- Defines notification type for an event queue
+**
+*/
+typedef enum {
+    EventQueueIsNative = 1,
+    EventQueueIsMonitored = 2
+} EventQueueType;
+
+
+struct PLEventQueue {
+    const char*         name;
+    PRCList             queue;
+    PRMonitor*          monitor;
+    PRThread*           handlerThread;
+    EventQueueType      type;
+    PRPackedBool        processingEvents;
+    PRPackedBool        notified;
+#if defined(_WIN32)
+    PRPackedBool        timerSet;
+#endif
+
+#if defined(XP_UNIX) && !defined(XP_MACOSX)
+#if defined(VMS)
+    int                 efn;
+#else
+    PRInt32             eventPipe[2];
+#endif
+    PLGetEventIDFunc    idFunc;
+    void*               idFuncClosure;
+#elif defined(_WIN32) || defined(XP_OS2)
+    HWND                eventReceiverWindow;
+    PRBool              removeMsg;
+#elif defined(XP_BEOS)
+    port_id             eventport;
+#elif defined(XP_MACOSX)
+#if defined(MAC_USE_CFRUNLOOPSOURCE)
+    CFRunLoopSourceRef  mRunLoopSource;
+    CFRunLoopRef        mMainRunLoop;
+    CFStringRef         mRunLoopModeStr;                                                                /* vbox */
+#elif defined(MAC_USE_CARBON_EVENT)
+    EventHandlerUPP     eventHandlerUPP;
+    EventHandlerRef     eventHandlerRef;
+#endif
+#endif
+};
+
+#define PR_EVENT_PTR(_qp) \
+    ((PLEvent*) ((char*) (_qp) - offsetof(PLEvent, link)))
+
+static PRStatus    _pl_SetupNativeNotifier(PLEventQueue* self);
+static void        _pl_CleanupNativeNotifier(PLEventQueue* self);
+static PRStatus    _pl_NativeNotify(PLEventQueue* self);
+static PRStatus    _pl_AcknowledgeNativeNotify(PLEventQueue* self);
+static void        _md_CreateEventQueue( PLEventQueue *eventQueue );
+static PRInt32     _pl_GetEventCount(PLEventQueue* self);
+
+
+#if defined(_WIN32) || defined(XP_OS2)
+#if defined(XP_OS2)
+ULONG _pr_PostEventMsgId;
+#else
+UINT _pr_PostEventMsgId;
+#endif /* OS2 */
+static char *_pr_eventWindowClass = "XPCOM:EventWindow";
+#endif /* Win32, OS2 */
+
+#if defined(_WIN32)
+
+static LPCTSTR _md_GetEventQueuePropName() {
+    static ATOM atom = 0;
+    if (!atom) {
+        atom = GlobalAddAtom("XPCOM_EventQueue");
+    }
+    return MAKEINTATOM(atom);
+}
+#endif
+
+#if defined(MAC_USE_CARBON_EVENT)
+enum {
+  kEventClassPL         = FOUR_CHAR_CODE('PLEC'),
+
+  kEventProcessPLEvents = 1,
+
+  kEventParamPLEventQueue = FOUR_CHAR_CODE('OWNQ')
+};
+
+static pascal Boolean _md_CarbonEventComparator(EventRef inEvent, void *inCompareData);
+#endif
+
+/*******************************************************************************
+ * Event Queue Operations
+ ******************************************************************************/
+
+/*
+** _pl_CreateEventQueue() -- Create the event queue
+**
+**
+*/
+static PLEventQueue * _pl_CreateEventQueue(const char *name,
+                                           PRThread *handlerThread,
+                                           EventQueueType  qtype)
+{
+    PRStatus err;
+    PLEventQueue* self = NULL;
+    PRMonitor* mon = NULL;
+
+    if (event_lm == NULL)
+        event_lm = PR_NewLogModule("event");
+
+    self = PR_NEWZAP(PLEventQueue);
+    if (self == NULL) return NULL;
+
+    mon = PR_NewNamedMonitor(name);
+    if (mon == NULL) goto error;
+
+    self->name = name;
+    self->monitor = mon;
+    self->handlerThread = handlerThread;
+    self->processingEvents = PR_FALSE;
+    self->type = qtype;
+#if defined(_WIN32)
+    self->timerSet = PR_FALSE;
+#endif
+#if defined(_WIN32) || defined(XP_OS2)
+    self->removeMsg = PR_TRUE;
+#endif
+
+    self->notified = PR_FALSE;
+
+    PR_INIT_CLIST(&self->queue);
+    if ( qtype == EventQueueIsNative ) {
+        err = _pl_SetupNativeNotifier(self);
+        if (err) goto error;
+        _md_CreateEventQueue( self );
+    }
+    return self;
+
+  error:
+    if (mon != NULL)
+        PR_DestroyMonitor(mon);
+    PR_DELETE(self);
+    return NULL;
+}
+
+PR_IMPLEMENT(PLEventQueue*)
+PL_CreateEventQueue(const char* name, PRThread* handlerThread)
+{
+    return( _pl_CreateEventQueue( name, handlerThread, EventQueueIsNative ));
+}
+
+PR_EXTERN(PLEventQueue *)
+PL_CreateNativeEventQueue(const char *name, PRThread *handlerThread)
+{
+    return( _pl_CreateEventQueue( name, handlerThread, EventQueueIsNative ));
+}
+
+PR_EXTERN(PLEventQueue *)
+PL_CreateMonitoredEventQueue(const char *name, PRThread *handlerThread)
+{
+    return( _pl_CreateEventQueue( name, handlerThread, EventQueueIsMonitored ));
+}
+
+PR_IMPLEMENT(PRMonitor*)
+PL_GetEventQueueMonitor(PLEventQueue* self)
+{
+    return self->monitor;
+}
+
+static void PR_CALLBACK
+_pl_destroyEvent(PLEvent* event, void* data, PLEventQueue* queue)
+{
+    PL_DequeueEvent(event, queue);
+    PL_DestroyEvent(event);
+}
+
+PR_IMPLEMENT(void)
+PL_DestroyEventQueue(PLEventQueue* self)
+{
+    PR_EnterMonitor(self->monitor);
+
+    /* destroy undelivered events */
+    PL_MapEvents(self, _pl_destroyEvent, NULL);
+
+    if ( self->type == EventQueueIsNative )
+        _pl_CleanupNativeNotifier(self);
+
+    /* destroying the monitor also destroys the name */
+    PR_ExitMonitor(self->monitor);
+    PR_DestroyMonitor(self->monitor);
+    PR_DELETE(self);
+
+}
+
+PR_IMPLEMENT(PRStatus)
+PL_PostEvent(PLEventQueue* self, PLEvent* event)
+{
+    PRStatus err = PR_SUCCESS;
+    PRMonitor* mon;
+
+    if (self == NULL)
+        return PR_FAILURE;
+
+    mon = self->monitor;
+    PR_EnterMonitor(mon);
+
+#if defined(XP_UNIX) && !defined(XP_MACOSX)
+    if (self->idFunc && event)
+        event->id = self->idFunc(self->idFuncClosure);
+#endif
+
+    /* insert event into thread's event queue: */
+    if (event != NULL) {
+        PR_APPEND_LINK(&event->link, &self->queue);
+    }
+
+    if (self->type == EventQueueIsNative && !self->notified) {
+        err = _pl_NativeNotify(self);
+
+        if (err != PR_SUCCESS)
+            goto error;
+
+        self->notified = PR_TRUE;
+    }
+
+    /*
+     * This may fall on deaf ears if we're really notifying the native
+     * thread, and no one has called PL_WaitForEvent (or PL_EventLoop):
+     */
+    err = PR_Notify(mon);
+
+error:
+    PR_ExitMonitor(mon);
+    return err;
+}
+
+PR_IMPLEMENT(void*)
+PL_PostSynchronousEvent(PLEventQueue* self, PLEvent* event)
+{
+    void* result;
+
+    if (self == NULL)
+        return NULL;
+
+    PR_ASSERT(event != NULL);
+
+    if (PR_GetCurrentThread() == self->handlerThread) {
+        /* Handle the case where the thread requesting the event handling
+         * is also the thread that's supposed to do the handling. */
+        result = event->handler(event);
+    }
+    else {
+        int i, entryCount;
+
+        event->lock = PR_NewLock();
+        if (!event->lock) {
+          return NULL;
+        }
+        event->condVar = PR_NewCondVar(event->lock);
+        if(!event->condVar) {
+          PR_DestroyLock(event->lock);
+          event->lock = NULL;
+          return NULL;
+        }
+
+        PR_Lock(event->lock);
+
+        entryCount = PR_GetMonitorEntryCount(self->monitor);
+
+        event->synchronousResult = (void*)PR_TRUE;
+
+        PL_PostEvent(self, event);
+
+        /* We need temporarily to give up our event queue monitor if
+           we're holding it, otherwise, the thread we're going to wait
+           for notification from won't be able to enter it to process
+           the event. */
+        if (entryCount) {
+            for (i = 0; i < entryCount; i++)
+                PR_ExitMonitor(self->monitor);
+        }
+
+        event->handled = PR_FALSE;
+
+        while (!event->handled) {
+            /* wait for event to be handled or destroyed */
+            PR_WaitCondVar(event->condVar, PR_INTERVAL_NO_TIMEOUT);
+        }
+
+        if (entryCount) {
+            for (i = 0; i < entryCount; i++)
+                PR_EnterMonitor(self->monitor);
+        }
+
+        result = event->synchronousResult;
+        event->synchronousResult = NULL;
+        PR_Unlock(event->lock);
+    }
+
+    /* For synchronous events, they're destroyed here on the caller's
+       thread before the result is returned. See PL_HandleEvent. */
+    PL_DestroyEvent(event);
+
+    return result;
+}
+
+PR_IMPLEMENT(PLEvent*)
+PL_GetEvent(PLEventQueue* self)
+{
+    PLEvent* event = NULL;
+    PRStatus err = PR_SUCCESS;
+
+    if (self == NULL)
+        return NULL;
+
+    PR_EnterMonitor(self->monitor);
+
+    if (!PR_CLIST_IS_EMPTY(&self->queue)) {
+        if ( self->type == EventQueueIsNative &&
+             self->notified                   &&
+             !self->processingEvents          &&
+             0 == _pl_GetEventCount(self)     )
+        {
+            err = _pl_AcknowledgeNativeNotify(self);
+            self->notified = PR_FALSE;
+        }
+        if (err)
+            goto done;
+
+        /* then grab the event and return it: */
+        event = PR_EVENT_PTR(self->queue.next);
+        PR_REMOVE_AND_INIT_LINK(&event->link);
+    }
+
+  done:
+    PR_ExitMonitor(self->monitor);
+    return event;
+}
+
+PR_IMPLEMENT(PRBool)
+PL_EventAvailable(PLEventQueue* self)
+{
+    PRBool result = PR_FALSE;
+
+    if (self == NULL)
+        return PR_FALSE;
+
+    PR_EnterMonitor(self->monitor);
+
+    if (!PR_CLIST_IS_EMPTY(&self->queue))
+        result = PR_TRUE;
+
+    PR_ExitMonitor(self->monitor);
+    return result;
+}
+
+PR_IMPLEMENT(void)
+PL_MapEvents(PLEventQueue* self, PLEventFunProc fun, void* data)
+{
+    PRCList* qp;
+
+    if (self == NULL)
+        return;
+
+    PR_EnterMonitor(self->monitor);
+    qp = self->queue.next;
+    while (qp != &self->queue) {
+        PLEvent* event = PR_EVENT_PTR(qp);
+        qp = qp->next;
+        (*fun)(event, data, self);
+    }
+    PR_ExitMonitor(self->monitor);
+}
+
+static void PR_CALLBACK
+_pl_DestroyEventForOwner(PLEvent* event, void* owner, PLEventQueue* queue)
+{
+    PR_ASSERT(PR_GetMonitorEntryCount(queue->monitor) > 0);
+    if (event->owner == owner) {
+        PR_LOG(event_lm, PR_LOG_DEBUG,
+               ("$$$ \tdestroying event %0x for owner %0x", event, owner));
+        PL_DequeueEvent(event, queue);
+
+        if (event->synchronousResult == (void*)PR_TRUE) {
+            PR_Lock(event->lock);
+            event->synchronousResult = NULL;
+            event->handled = PR_TRUE;
+            PR_NotifyCondVar(event->condVar);
+            PR_Unlock(event->lock);
+        }
+        else {
+            PL_DestroyEvent(event);
+        }
+    }
+    else {
+        PR_LOG(event_lm, PR_LOG_DEBUG,
+               ("$$$ \tskipping event %0x for owner %0x", event, owner));
+    }
+}
+
+PR_IMPLEMENT(void)
+PL_RevokeEvents(PLEventQueue* self, void* owner)
+{
+    if (self == NULL)
+        return;
+
+    PR_LOG(event_lm, PR_LOG_DEBUG,
+         ("$$$ revoking events for owner %0x", owner));
+
+    /*
+    ** First we enter the monitor so that no one else can post any events
+    ** to the queue:
+    */
+    PR_EnterMonitor(self->monitor);
+    PR_LOG(event_lm, PR_LOG_DEBUG, ("$$$ owner %0x, entered monitor", owner));
+
+    /*
+    ** Discard any pending events for this owner:
+    */
+    PL_MapEvents(self, _pl_DestroyEventForOwner, owner);
+
+#ifdef DEBUG
+    {
+        PRCList* qp = self->queue.next;
+        while (qp != &self->queue) {
+            PLEvent* event = PR_EVENT_PTR(qp);
+            qp = qp->next;
+            PR_ASSERT(event->owner != owner);
+        }
+    }
+#endif /* DEBUG */
+
+    PR_ExitMonitor(self->monitor);
+
+    PR_LOG(event_lm, PR_LOG_DEBUG,
+           ("$$$ revoking events for owner %0x", owner));
+}
+
+static PRInt32
+_pl_GetEventCount(PLEventQueue* self)
+{
+    PRCList* node;
+    PRInt32  count = 0;
+
+    PR_EnterMonitor(self->monitor);
+    node = PR_LIST_HEAD(&self->queue);
+    while (node != &self->queue) {
+        count++;
+        node = PR_NEXT_LINK(node);
+    }
+    PR_ExitMonitor(self->monitor);
+
+    return count;
+}
+
+PR_IMPLEMENT(void)
+PL_ProcessPendingEvents(PLEventQueue* self)
+{
+    PRInt32 count;
+
+    if (self == NULL)
+        return;
+
+
+    PR_EnterMonitor(self->monitor);
+
+    if (self->processingEvents) {
+        _pl_AcknowledgeNativeNotify(self);
+        self->notified = PR_FALSE;
+        PR_ExitMonitor(self->monitor);
+        return;
+    }
+    self->processingEvents = PR_TRUE;
+
+    /* Only process the events that are already in the queue, and
+     * not any new events that get added. Do this by counting the
+     * number of events currently in the queue
+     */
+    count = _pl_GetEventCount(self);
+    PR_ExitMonitor(self->monitor);
+
+    while (count-- > 0) {
+        PLEvent* event = PL_GetEvent(self);
+        if (event == NULL)
+            break;
+
+        PR_LOG(event_lm, PR_LOG_DEBUG, ("$$$ processing event"));
+        PL_HandleEvent(event);
+        PR_LOG(event_lm, PR_LOG_DEBUG, ("$$$ done processing event"));
+    }
+
+    PR_EnterMonitor(self->monitor);
+
+    if (self->type == EventQueueIsNative) {
+        count = _pl_GetEventCount(self);
+
+        if (count <= 0) {
+            _pl_AcknowledgeNativeNotify(self);
+            self->notified = PR_FALSE;
+        }
+        else {
+            _pl_NativeNotify(self);
+            self->notified = PR_TRUE;
+        }
+
+    }
+    self->processingEvents = PR_FALSE;
+
+    PR_ExitMonitor(self->monitor);
+}
+
+/*******************************************************************************
+ * Event Operations
+ ******************************************************************************/
+
+PR_IMPLEMENT(void)
+PL_InitEvent(PLEvent* self, void* owner,
+             PLHandleEventProc handler,
+             PLDestroyEventProc destructor)
+{
+#ifdef PL_POST_TIMINGS
+    self->postTime = PR_IntervalNow();
+#endif
+    PR_INIT_CLIST(&self->link);
+    self->handler = handler;
+    self->destructor = destructor;
+    self->owner = owner;
+    self->synchronousResult = NULL;
+    self->handled = PR_FALSE;
+    self->lock = NULL;
+    self->condVar = NULL;
+#if defined(XP_UNIX) && !defined(XP_MACOSX)
+    self->id = 0;
+#endif
+}
+
+PR_IMPLEMENT(void*)
+PL_GetEventOwner(PLEvent* self)
+{
+    return self->owner;
+}
+
+PR_IMPLEMENT(void)
+PL_HandleEvent(PLEvent* self)
+{
+    void* result;
+    if (self == NULL)
+        return;
+
+    /* This event better not be on an event queue anymore. */
+    PR_ASSERT(PR_CLIST_IS_EMPTY(&self->link));
+
+    result = self->handler(self);
+    if (NULL != self->synchronousResult) {
+        PR_Lock(self->lock);
+        self->synchronousResult = result;
+        self->handled = PR_TRUE;
+        PR_NotifyCondVar(self->condVar);
+        PR_Unlock(self->lock);
+    }
+    else {
+        /* For asynchronous events, they're destroyed by the event-handler
+           thread. See PR_PostSynchronousEvent. */
+        PL_DestroyEvent(self);
+    }
+}
+#ifdef PL_POST_TIMINGS
+static long s_eventCount = 0;
+static long s_totalTime  = 0;
+#endif
+
+PR_IMPLEMENT(void)
+PL_DestroyEvent(PLEvent* self)
+{
+    if (self == NULL)
+        return;
+
+    /* This event better not be on an event queue anymore. */
+    PR_ASSERT(PR_CLIST_IS_EMPTY(&self->link));
+
+    if(self->condVar)
+      PR_DestroyCondVar(self->condVar);
+    if(self->lock)
+      PR_DestroyLock(self->lock);
+
+#ifdef PL_POST_TIMINGS
+    s_totalTime += PR_IntervalNow() - self->postTime;
+    s_eventCount++;
+    printf("$$$ running avg (%d) \n", PR_IntervalToMilliseconds(s_totalTime/s_eventCount));
+#endif
+
+    self->destructor(self);
+}
+
+PR_IMPLEMENT(void)
+PL_DequeueEvent(PLEvent* self, PLEventQueue* queue)
+{
+    if (self == NULL)
+        return;
+
+    /* Only the owner is allowed to dequeue events because once the
+       client has put it in the queue, they have no idea whether it's
+       been processed and destroyed or not. */
+
+    PR_ASSERT(queue->handlerThread == PR_GetCurrentThread());
+
+    PR_EnterMonitor(queue->monitor);
+
+    PR_ASSERT(!PR_CLIST_IS_EMPTY(&self->link));
+
+#if 0
+    /*  I do not think that we need to do this anymore.
+        if we do not acknowledge and this is the only
+        only event in the queue, any calls to process
+        the eventQ will be effective noop.
+    */
+    if (queue->type == EventQueueIsNative)
+      _pl_AcknowledgeNativeNotify(queue);
+#endif
+
+    PR_REMOVE_AND_INIT_LINK(&self->link);
+
+    PR_ExitMonitor(queue->monitor);
+}
+
+PR_IMPLEMENT(void)
+PL_FavorPerformanceHint(PRBool favorPerformanceOverEventStarvation,
+                        PRUint32 starvationDelay)
+{
+#if defined(_WIN32)
+
+    _md_StarvationDelay = starvationDelay;
+
+    if (favorPerformanceOverEventStarvation) {
+        _md_PerformanceSetting++;
+        return;
+    }
+
+    _md_PerformanceSetting--;
+
+    if (_md_PerformanceSetting == 0) {
+      /* Switched from allowing event starvation to no event starvation so grab
+         the current time to determine when to actually switch to using timers
+         instead of posted WM_APP messages. */
+      _md_SwitchTime = PR_IntervalToMilliseconds(PR_IntervalNow());
+    }
+
+#endif
+}
+
+/*******************************************************************************
+ * Pure Event Queues
+ *
+ * For when you're only processing PLEvents and there is no native
+ * select, thread messages, or AppleEvents.
+ ******************************************************************************/
+
+PR_IMPLEMENT(PLEvent*)
+PL_WaitForEvent(PLEventQueue* self)
+{
+    PLEvent* event;
+    PRMonitor* mon;
+
+    if (self == NULL)
+        return NULL;
+
+    mon = self->monitor;
+    PR_EnterMonitor(mon);
+
+    while ((event = PL_GetEvent(self)) == NULL) {
+        PRStatus err;
+        PR_LOG(event_lm, PR_LOG_DEBUG, ("$$$ waiting for event"));
+        err = PR_Wait(mon, PR_INTERVAL_NO_TIMEOUT);
+        if ((err == PR_FAILURE)
+            && (PR_PENDING_INTERRUPT_ERROR == PR_GetError())) break;
+    }
+
+    PR_ExitMonitor(mon);
+    return event;
+}
+
+PR_IMPLEMENT(void)
+PL_EventLoop(PLEventQueue* self)
+{
+    if (self == NULL)
+        return;
+
+    while (PR_TRUE) {
+        PLEvent* event = PL_WaitForEvent(self);
+        if (event == NULL) {
+            /* This can only happen if the current thread is interrupted */
+            return;
+        }
+
+        PR_LOG(event_lm, PR_LOG_DEBUG, ("$$$ processing event"));
+        PL_HandleEvent(event);
+        PR_LOG(event_lm, PR_LOG_DEBUG, ("$$$ done processing event"));
+    }
+}
+
+/*******************************************************************************
+ * Native Event Queues
+ *
+ * For when you need to call select, or WaitNextEvent, and yet also want
+ * to handle PLEvents.
+ ******************************************************************************/
+
+static PRStatus
+_pl_SetupNativeNotifier(PLEventQueue* self)
+{
+#if defined(VMS)
+    unsigned int status;
+    self->idFunc = 0;
+    self->idFuncClosure = 0;
+    status = LIB$GET_EF(&self->efn);
+    if (!$VMS_STATUS_SUCCESS(status))
+        return PR_FAILURE;
+    PR_LOG(event_lm, PR_LOG_DEBUG,
+           ("$$$ Allocated event flag %d", self->efn));
+    return PR_SUCCESS;
+#elif defined(XP_UNIX) && !defined(XP_MACOSX)
+    int err;
+    int flags;
+
+    self->idFunc = 0;
+    self->idFuncClosure = 0;
+
+    err = pipe(self->eventPipe);
+    if (err != 0) {
+        return PR_FAILURE;
+    }
+#ifdef VBOX
+    fcntl(self->eventPipe[0], F_SETFD, FD_CLOEXEC);
+    fcntl(self->eventPipe[1], F_SETFD, FD_CLOEXEC);
+#endif
+
+    /* make the pipe nonblocking */
+    flags = fcntl(self->eventPipe[0], F_GETFL, 0);
+    if (flags == -1) {
+        goto failed;
+    }
+    err = fcntl(self->eventPipe[0], F_SETFL, flags | O_NONBLOCK);
+    if (err == -1) {
+        goto failed;
+    }
+    flags = fcntl(self->eventPipe[1], F_GETFL, 0);
+    if (flags == -1) {
+        goto failed;
+    }
+    err = fcntl(self->eventPipe[1], F_SETFL, flags | O_NONBLOCK);
+    if (err == -1) {
+        goto failed;
+    }
+    return PR_SUCCESS;
+
+failed:
+    close(self->eventPipe[0]);
+    close(self->eventPipe[1]);
+    return PR_FAILURE;
+#elif defined(XP_BEOS)
+    /* hook up to the nsToolkit queue, however the appshell
+     * isn't necessairly started, so we might have to create
+     * the queue ourselves
+     */
+    char portname[64];
+    char semname[64];
+    PR_snprintf(portname, sizeof(portname), "event%lx",
+                (long unsigned) self->handlerThread);
+    PR_snprintf(semname, sizeof(semname), "sync%lx",
+                (long unsigned) self->handlerThread);
+
+    if((self->eventport = find_port(portname)) < 0)
+    {
+        /* create port
+         */
+        self->eventport = create_port(500, portname);
+
+        /* We don't use the sem, but it has to be there
+         */
+        create_sem(0, semname);
+    }
+
+    return PR_SUCCESS;
+#else
+    return PR_SUCCESS;
+#endif
+}
+
+static void
+_pl_CleanupNativeNotifier(PLEventQueue* self)
+{
+#if defined(VMS)
+    {
+        unsigned int status;
+        PR_LOG(event_lm, PR_LOG_DEBUG,
+           ("$$$ Freeing event flag %d", self->efn));
+        status = LIB$FREE_EF(&self->efn);
+    }
+#elif defined(XP_UNIX) && !defined(XP_MACOSX)
+    close(self->eventPipe[0]);
+    close(self->eventPipe[1]);
+#elif defined(_WIN32)
+    if (self->timerSet) {
+        KillTimer(self->eventReceiverWindow, TIMER_ID);
+        self->timerSet = PR_FALSE;
+    }
+    RemoveProp(self->eventReceiverWindow, _md_GetEventQueuePropName());
+
+    /* DestroyWindow doesn't do anything when called from a non ui thread.  Since
+     * self->eventReceiverWindow was created on the ui thread, it must be destroyed
+     * on the ui thread.
+     */
+    SendMessage(self->eventReceiverWindow, WM_CLOSE, 0, 0);
+
+#elif defined(XP_OS2)
+    WinDestroyWindow(self->eventReceiverWindow);
+#elif defined(MAC_USE_CFRUNLOOPSOURCE)
+
+    CFRunLoopRemoveSource(self->mMainRunLoop, self->mRunLoopSource, kCFRunLoopCommonModes);
+    CFRunLoopRemoveSource(self->mMainRunLoop, self->mRunLoopSource, self->mRunLoopModeStr);             /* vbox */
+    CFRelease(self->mRunLoopSource);
+    CFRelease(self->mMainRunLoop);
+    CFRelease(self->mRunLoopModeStr);                                                                   /* vbox */
+
+#elif defined(MAC_USE_CARBON_EVENT)
+    EventComparatorUPP comparator = NewEventComparatorUPP(_md_CarbonEventComparator);
+    PR_ASSERT(comparator != NULL);
+    if (comparator) {
+      FlushSpecificEventsFromQueue(GetMainEventQueue(), comparator, self);
+      DisposeEventComparatorUPP(comparator);
+    }
+    DisposeEventHandlerUPP(self->eventHandlerUPP);
+    RemoveEventHandler(self->eventHandlerRef);
+#endif
+}
+
+#if defined(_WIN32)
+
+static PRBool   _md_WasInputPending = PR_FALSE;
+static PRUint32 _md_InputTime = 0;
+static PRBool   _md_WasPaintPending = PR_FALSE;
+static PRUint32 _md_PaintTime = 0;
+/* last mouse location */
+static POINT    _md_LastMousePos;
+
+/*******************************************************************************
+ * Timer callback function. Timers are used on WIN32 instead of APP events
+ * when there are pending UI events because APP events can cause the GUI to lockup
+ * because posted messages are processed before other messages.
+ ******************************************************************************/
+
+static void CALLBACK _md_TimerProc( HWND hwnd, UINT uMsg, UINT idEvent, DWORD dwTime )
+{
+    PREventQueue* queue =  (PREventQueue  *) GetProp(hwnd, _md_GetEventQueuePropName());
+    PR_ASSERT(queue != NULL);
+
+    KillTimer(hwnd, TIMER_ID);
+    queue->timerSet = PR_FALSE;
+    queue->removeMsg = PR_FALSE;
+    PL_ProcessPendingEvents( queue );
+    queue->removeMsg = PR_TRUE;
+}
+
+static PRBool _md_IsWIN9X = PR_FALSE;
+static PRBool _md_IsOSSet = PR_FALSE;
+
+static void _md_DetermineOSType()
+{
+    OSVERSIONINFO os;
+    os.dwOSVersionInfoSize = sizeof(OSVERSIONINFO);
+    GetVersionEx(&os);
+    if (VER_PLATFORM_WIN32_WINDOWS == os.dwPlatformId) {
+        _md_IsWIN9X = PR_TRUE;
+    }
+}
+
+static PRUint32 _md_GetPaintStarvationLimit()
+{
+    if (! _md_IsOSSet) {
+        _md_DetermineOSType();
+        _md_IsOSSet = PR_TRUE;
+    }
+
+    if (_md_IsWIN9X) {
+        return WIN9X_PAINT_STARVATION_LIMIT;
+    }
+
+    return PAINT_STARVATION_LIMIT;
+}
+
+
+/*
+ * Determine if an event is being starved (i.e the starvation limit has
+ * been exceeded.
+ * Note: this function uses the current setting and updates the contents
+ * of the wasPending and lastTime arguments
+ *
+ * ispending:       PR_TRUE if the event is currently pending
+ * starvationLimit: Threshold defined in milliseconds for determining when
+ *                  the event has been held in the queue too long
+ * wasPending:      PR_TRUE if the last time _md_EventIsStarved was called
+ *                  the event was pending.  This value is updated within
+ *                  this function.
+ * lastTime:        Holds the last time the event was in the queue.
+ *                  This value is updated within this function
+ * returns:         PR_TRUE if the event is starved, PR_FALSE otherwise
+ */
+
+static PRBool _md_EventIsStarved(PRBool isPending, PRUint32 starvationLimit,
+                                 PRBool *wasPending, PRUint32 *lastTime,
+                                 PRUint32 currentTime)
+{
+    if (*wasPending && isPending) {
+        /*
+         * It was pending previously and the event is still
+         * pending so check to see if the elapsed time is
+         * over the limit which indicates the event was starved
+         */
+        if ((currentTime - *lastTime) > starvationLimit) {
+            return PR_TRUE; /* pending and over the limit */
+        }
+
+        return PR_FALSE; /* pending but within the limit */
+    }
+
+    if (isPending) {
+        /*
+         * was_pending must be false so record the current time
+         * so the elapsed time can be computed the next time this
+         * function is called
+         */
+        *lastTime = currentTime;
+        *wasPending = PR_TRUE;
+        return PR_FALSE;
+    }
+
+    /* Event is no longer pending */
+    *wasPending = PR_FALSE;
+    return PR_FALSE;
+}
+
+/* Determines if the there is a pending Mouse or input event */
+
+static PRBool _md_IsInputPending(WORD qstatus)
+{
+    /* Return immediately there aren't any pending input or paints. */
+    if (qstatus == 0) {
+        return PR_FALSE;
+    }
+
+    /* Is there anything other than a QS_MOUSEMOVE pending? */
+    if ((qstatus & QS_MOUSEBUTTON) ||
+        (qstatus & QS_KEY) ||
+        (qstatus & QS_HOTKEY)) {
+        return PR_TRUE;
+    }
+
+    /*
+     * Mouse moves need extra processing to determine if the mouse
+     * pointer actually changed location because Windows automatically
+     * generates WM_MOVEMOVE events when a new window is created which
+     * we need to filter out.
+     */
+    if (qstatus & QS_MOUSEMOVE) {
+        POINT cursorPos;
+        GetCursorPos(&cursorPos);
+        if ((_md_LastMousePos.x == cursorPos.x) &&
+            (_md_LastMousePos.y == cursorPos.y)) {
+            return PR_FALSE; /* This is a fake mouse move */
+        }
+
+        /* Real mouse move */
+        _md_LastMousePos.x = cursorPos.x;
+        _md_LastMousePos.y = cursorPos.y;
+        return PR_TRUE;
+    }
+
+    return PR_FALSE;
+}
+
+static PRStatus
+_pl_NativeNotify(PLEventQueue* self)
+{
+#ifdef USE_TIMER
+    WORD qstatus;
+
+    PRUint32 now = PR_IntervalToMilliseconds(PR_IntervalNow());
+
+    /* Since calls to set the _md_PerformanceSetting can be nested
+     * only performance setting values <= 0 will potentially trigger
+     * the use of a timer.
+     */
+    if ((_md_PerformanceSetting <= 0) &&
+        ((now - _md_SwitchTime) > _md_StarvationDelay)) {
+        SetTimer(self->eventReceiverWindow, TIMER_ID, 0 ,_md_TimerProc);
+        self->timerSet = PR_TRUE;
+        _md_WasInputPending = PR_FALSE;
+        _md_WasPaintPending = PR_FALSE;
+        return PR_SUCCESS;
+    }
+
+    qstatus = HIWORD(GetQueueStatus(QS_INPUT | QS_PAINT));
+
+    /* Check for starved input */
+    if (_md_EventIsStarved( _md_IsInputPending(qstatus),
+                            INPUT_STARVATION_LIMIT,
+                            &_md_WasInputPending,
+                            &_md_InputTime,
+                            now )) {
+        /*
+         * Use a timer for notification. Timers have the lowest priority.
+         * They are not processed until all other events have been processed.
+         * This allows any starved paints and input to be processed.
+         */
+        SetTimer(self->eventReceiverWindow, TIMER_ID, 0 ,_md_TimerProc);
+        self->timerSet = PR_TRUE;
+
+        /*
+         * Clear any pending paint.  _md_WasInputPending was cleared in
+         * _md_EventIsStarved.
+         */
+        _md_WasPaintPending = PR_FALSE;
+        return PR_SUCCESS;
+    }
+
+    if (_md_EventIsStarved( (qstatus & QS_PAINT),
+                            _md_GetPaintStarvationLimit(),
+                            &_md_WasPaintPending,
+                            &_md_PaintTime,
+                            now) ) {
+        /*
+         * Use a timer for notification. Timers have the lowest priority.
+         * They are not processed until all other events have been processed.
+         * This allows any starved paints and input to be processed
+         */
+        SetTimer(self->eventReceiverWindow, TIMER_ID, 0 ,_md_TimerProc);
+        self->timerSet = PR_TRUE;
+
+        /*
+         * Clear any pending input.  _md_WasPaintPending was cleared in
+         * _md_EventIsStarved.
+         */
+        _md_WasInputPending = PR_FALSE;
+        return PR_SUCCESS;
+    }
+
+    /*
+     * Nothing is being starved so post a message instead of using a timer.
+     * Posted messages are processed before other messages so they have the
+     * highest priority.
+     */
+#endif
+    PostMessage( self->eventReceiverWindow, _pr_PostEventMsgId,
+                (WPARAM)0, (LPARAM)self );
+
+    return PR_SUCCESS;
+}/* --- end _pl_NativeNotify() --- */
+#endif
+
+
+#if defined(XP_OS2)
+static PRStatus
+_pl_NativeNotify(PLEventQueue* self)
+{
+    BOOL rc = WinPostMsg( self->eventReceiverWindow, _pr_PostEventMsgId,
+                          0, MPFROMP(self));
+    return (rc == TRUE) ? PR_SUCCESS : PR_FAILURE;
+}/* --- end _pl_NativeNotify() --- */
+#endif /* XP_OS2 */
+
+#if defined(VMS)
+/* Just set the event flag */
+static PRStatus
+_pl_NativeNotify(PLEventQueue* self)
+{
+    unsigned int status;
+    PR_LOG(event_lm, PR_LOG_DEBUG,
+           ("_pl_NativeNotify: self=%p efn=%d",
+            self, self->efn));
+    status = SYS$SETEF(self->efn);
+    return ($VMS_STATUS_SUCCESS(status)) ? PR_SUCCESS : PR_FAILURE;
+}/* --- end _pl_NativeNotify() --- */
+#elif defined(XP_UNIX) && !defined(XP_MACOSX)
+
+static PRStatus
+_pl_NativeNotify(PLEventQueue* self)
+{
+#define NOTIFY_TOKEN    0xFA
+    PRInt32 count;
+    unsigned char buf[] = { NOTIFY_TOKEN };
+
+# ifdef VBOX
+    /* Don't write two chars, because we'll only acknowledge one and that'll
+       cause trouble for anyone selecting/polling on the read descriptor. */
+    if (self->notified)
+        return PR_SUCCESS;
+# endif
+
+    PR_LOG(event_lm, PR_LOG_DEBUG,
+           ("_pl_NativeNotify: self=%p",
+            self));
+    count = write(self->eventPipe[1], buf, 1);
+    if (count == 1)
+        return PR_SUCCESS;
+    if (count == -1 && (errno == EAGAIN || errno == EWOULDBLOCK))
+        return PR_SUCCESS;
+    return PR_FAILURE;
+}/* --- end _pl_NativeNotify() --- */
+#endif /* defined(XP_UNIX) && !defined(XP_MACOSX) */
+
+#if defined(XP_BEOS)
+struct ThreadInterfaceData
+{
+    void  *data;
+    int32 sync;
+};
+
+static PRStatus
+_pl_NativeNotify(PLEventQueue* self)
+{
+    struct ThreadInterfaceData id;
+    id.data = self;
+    id.sync = false;
+    write_port(self->eventport, 'natv', &id, sizeof(id));
+
+    return PR_SUCCESS;    /* Is this correct? */
+}
+#endif /* XP_BEOS */
+
+#if defined(XP_MACOSX)
+static PRStatus
+_pl_NativeNotify(PLEventQueue* self)
+{
+#if defined(MAC_USE_CFRUNLOOPSOURCE)
+  	CFRunLoopSourceSignal(self->mRunLoopSource);
+  	CFRunLoopWakeUp(self->mMainRunLoop);
+#elif defined(MAC_USE_CARBON_EVENT)
+    OSErr err;
+    EventRef newEvent;
+    if (CreateEvent(NULL, kEventClassPL, kEventProcessPLEvents,
+                    0, kEventAttributeNone, &newEvent) != noErr)
+        return PR_FAILURE;
+    err = SetEventParameter(newEvent, kEventParamPLEventQueue,
+                            typeUInt32, sizeof(PREventQueue*), &self);
+    if (err == noErr) {
+        err = PostEventToQueue(GetMainEventQueue(), newEvent, kEventPriorityLow);
+        ReleaseEvent(newEvent);
+    }
+    if (err != noErr)
+        return PR_FAILURE;
+#endif
+    return PR_SUCCESS;
+}
+#endif /* defined(XP_MACOSX) */
+
+static PRStatus
+_pl_AcknowledgeNativeNotify(PLEventQueue* self)
+{
+#if defined(_WIN32) || defined(XP_OS2)
+#ifdef XP_OS2
+    QMSG aMsg;
+#else
+    MSG aMsg;
+#endif
+    /*
+     * only remove msg when we've been called directly by
+     * PL_ProcessPendingEvents, not when we've been called by
+     * the window proc because the window proc will remove the
+     * msg for us.
+     */
+    if (self->removeMsg) {
+        PR_LOG(event_lm, PR_LOG_DEBUG,
+               ("_pl_AcknowledgeNativeNotify: self=%p", self));
+#ifdef XP_OS2
+        WinPeekMsg((HAB)0, &aMsg, self->eventReceiverWindow,
+                   _pr_PostEventMsgId, _pr_PostEventMsgId, PM_REMOVE);
+#else
+        PeekMessage(&aMsg, self->eventReceiverWindow,
+                    _pr_PostEventMsgId, _pr_PostEventMsgId, PM_REMOVE);
+        if (self->timerSet) {
+            KillTimer(self->eventReceiverWindow, TIMER_ID);
+            self->timerSet = PR_FALSE;
+        }
+#endif
+    }
+    return PR_SUCCESS;
+#elif defined(VMS)
+    PR_LOG(event_lm, PR_LOG_DEBUG,
+            ("_pl_AcknowledgeNativeNotify: self=%p efn=%d",
+             self, self->efn));
+    /*
+    ** If this is the last entry, then clear the event flag. Also make sure
+    ** the flag is cleared on any spurious wakeups.
+    */
+    sys$clref(self->efn);
+    return PR_SUCCESS;
+#elif defined(XP_UNIX) && !defined(XP_MACOSX)
+
+    PRInt32 count;
+    unsigned char c;
+    PR_LOG(event_lm, PR_LOG_DEBUG,
+            ("_pl_AcknowledgeNativeNotify: self=%p",
+             self));
+    /* consume the byte NativeNotify put in our pipe: */
+    count = read(self->eventPipe[0], &c, 1);
+    if ((count == 1) && (c == NOTIFY_TOKEN))
+        return PR_SUCCESS;
+    if ((count == -1) && ((errno == EAGAIN) || (errno == EWOULDBLOCK)))
+        return PR_SUCCESS;
+    return PR_FAILURE;
+#elif defined(MAC_USE_CFRUNLOOPSOURCE)                                                                  /* vbox */
+                                                                                                        /* vbox */
+    CFRunLoopRunInMode(self->mRunLoopModeStr, 0.0, 1);                                                  /* vbox */
+    return PR_SUCCESS;                                                                                  /* vbox */
+#else
+
+    /* nothing to do on the other platforms */
+    return PR_SUCCESS;
+#endif
+}
+
+PR_IMPLEMENT(PRInt32)
+PL_GetEventQueueSelectFD(PLEventQueue* self)
+{
+    if (self == NULL)
+    return -1;
+
+#if defined(VMS)
+    return -(self->efn);
+#elif defined(XP_UNIX) && !defined(XP_MACOSX)
+    return self->eventPipe[0];
+#else
+    return -1;    /* other platforms don't handle this (yet) */
+#endif
+}
+
+PR_IMPLEMENT(PRBool)
+PL_IsQueueOnCurrentThread( PLEventQueue *queue )
+{
+    PRThread *me = PR_GetCurrentThread();
+    return me == queue->handlerThread;
+}
+
+PR_EXTERN(PRBool)
+PL_IsQueueNative(PLEventQueue *queue)
+{
+    return queue->type == EventQueueIsNative ? PR_TRUE : PR_FALSE;
+}
+
+#if defined(_WIN32)
+/*
+** Global Instance handle...
+** In Win32 this is the module handle of the DLL.
+**
+*/
+static HINSTANCE _pr_hInstance;
+#endif
+
+
+#if defined(_WIN32)
+
+/*
+** Initialization routine for the DLL...
+*/
+
+BOOL WINAPI DllMain (HINSTANCE hDLL, DWORD dwReason, LPVOID lpReserved)
+{
+    switch (dwReason)
+    {
+      case DLL_PROCESS_ATTACH:
+        _pr_hInstance = hDLL;
+        break;
+
+      case DLL_THREAD_ATTACH:
+        break;
+
+      case DLL_THREAD_DETACH:
+        break;
+
+      case DLL_PROCESS_DETACH:
+        _pr_hInstance = NULL;
+        break;
+    }
+
+    return TRUE;
+}
+#endif
+
+
+#if defined(_WIN32) || defined(XP_OS2)
+#ifdef XP_OS2
+MRESULT EXPENTRY
+_md_EventReceiverProc(HWND hwnd, ULONG uMsg, MPARAM wParam, MPARAM lParam)
+#else
+LRESULT CALLBACK
+_md_EventReceiverProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
+#endif
+{
+    if (_pr_PostEventMsgId == uMsg )
+    {
+        PREventQueue *queue = (PREventQueue *)lParam;
+        queue->removeMsg = PR_FALSE;
+        PL_ProcessPendingEvents(queue);
+        queue->removeMsg = PR_TRUE;
+#ifdef XP_OS2
+        return MRFROMLONG(TRUE);
+#else
+        return TRUE;
+#endif
+    }
+    return DefWindowProc(hwnd, uMsg, wParam, lParam);
+}
+
+static PRBool   isInitialized;
+static PRCallOnceType once;
+static PRLock   *initLock;
+
+/*
+** InitWinEventLib() -- Create the Windows initialization lock
+**
+*/
+static PRStatus InitEventLib( void )
+{
+    PR_ASSERT( initLock == NULL );
+
+    initLock = PR_NewLock();
+    return initLock ? PR_SUCCESS : PR_FAILURE;
+}
+
+#endif /* Win32, OS2 */
+
+#if defined(_WIN32)
+
+/*
+** _md_CreateEventQueue() -- ModelDependent initializer
+*/
+static void _md_CreateEventQueue( PLEventQueue *eventQueue )
+{
+    WNDCLASS wc;
+
+    /*
+    ** If this is the first call to PL_InitializeEventsLib(),
+    ** make the call to InitWinEventLib() to create the initLock.
+    **
+    ** Then lock the initializer lock to insure that
+    ** we have exclusive control over the initialization sequence.
+    **
+    */
+
+
+    /* Register the windows message for XPCOM Event notification */
+    _pr_PostEventMsgId = RegisterWindowMessage("XPCOM_PostEvent");
+
+    /* Register the class for the event receiver window */
+    if (!GetClassInfo(_pr_hInstance, _pr_eventWindowClass, &wc)) {
+        wc.style         = 0;
+        wc.lpfnWndProc   = _md_EventReceiverProc;
+        wc.cbClsExtra    = 0;
+        wc.cbWndExtra    = 0;
+        wc.hInstance     = _pr_hInstance;
+        wc.hIcon         = NULL;
+        wc.hCursor       = NULL;
+        wc.hbrBackground = (HBRUSH) NULL;
+        wc.lpszMenuName  = (LPCSTR) NULL;
+        wc.lpszClassName = _pr_eventWindowClass;
+        RegisterClass(&wc);
+    }
+
+    /* Create the event receiver window */
+    eventQueue->eventReceiverWindow = CreateWindow(_pr_eventWindowClass,
+                                        "XPCOM:EventReceiver",
+                                            0, 0, 0, 10, 10,
+                                            NULL, NULL, _pr_hInstance,
+                                            NULL);
+    PR_ASSERT(eventQueue->eventReceiverWindow);
+    /* Set a property which can be used to retrieve the event queue
+     * within the _md_TimerProc callback
+     */
+    SetProp(eventQueue->eventReceiverWindow,
+            _md_GetEventQueuePropName(), (HANDLE)eventQueue);
+
+    return;
+} /* end _md_CreateEventQueue() */
+#endif /* Winxx */
+
+#if defined(XP_OS2)
+/*
+** _md_CreateEventQueue() -- ModelDependent initializer
+*/
+static void _md_CreateEventQueue( PLEventQueue *eventQueue )
+{
+    /* Must have HMQ for this & can't assume we already have appshell */
+    if( FALSE == WinQueryQueueInfo( HMQ_CURRENT, NULL, 0))
+    {
+       PPIB ppib;
+       PTIB ptib;
+       HAB hab;
+       HMQ hmq;
+
+       /* Set our app to be a PM app before attempting Win calls */
+       DosGetInfoBlocks(&ptib, &ppib);
+       ppib->pib_ultype = 3;
+
+       hab = WinInitialize(0);
+       hmq = WinCreateMsgQueue(hab, 0);
+       PR_ASSERT(hmq);
+    }
+
+    if( !_pr_PostEventMsgId)
+    {
+        WinRegisterClass( 0 /* hab_current */,
+                         _pr_eventWindowClass,
+                         _md_EventReceiverProc,
+                         0, 0);
+
+        _pr_PostEventMsgId = WinAddAtom( WinQuerySystemAtomTable(),
+                                        "XPCOM_PostEvent");
+    }
+
+    eventQueue->eventReceiverWindow = WinCreateWindow( HWND_DESKTOP,
+                                                       _pr_eventWindowClass,
+                                                       "", 0,
+                                                       0, 0, 0, 0,
+                                                       HWND_DESKTOP,
+                                                       HWND_TOP,
+                                                       0,
+                                                       NULL,
+                                                       NULL);
+    PR_ASSERT(eventQueue->eventReceiverWindow);
+
+    return;
+} /* end _md_CreateEventQueue() */
+#endif /* XP_OS2 */
+
+#if (defined(XP_UNIX) && !defined(XP_MACOSX)) || defined(XP_BEOS)
+/*
+** _md_CreateEventQueue() -- ModelDependent initializer
+*/
+static void _md_CreateEventQueue( PLEventQueue *eventQueue )
+{
+    /* there's really nothing special to do here,
+    ** the guts of the unix stuff is in the setupnativenotify
+    ** and related functions.
+    */
+    return;
+} /* end _md_CreateEventQueue() */
+#endif /* (defined(XP_UNIX) && !defined(XP_MACOSX)) || defined(XP_BEOS) */
+
+#if defined(MAC_USE_CFRUNLOOPSOURCE)
+static void _md_EventReceiverProc(void *info)
+{
+  PLEventQueue *queue = (PLEventQueue*)info;
+  PL_ProcessPendingEvents(queue);
+}
+
+#elif defined(MAC_USE_CARBON_EVENT)
+/*
+** _md_CreateEventQueue() -- ModelDependent initializer
+*/
+
+static pascal OSStatus _md_EventReceiverProc(EventHandlerCallRef nextHandler,
+                                             EventRef inEvent,
+                                             void* userData)
+{
+    if (GetEventClass(inEvent) == kEventClassPL &&
+        GetEventKind(inEvent) == kEventProcessPLEvents)
+    {
+        PREventQueue *queue;
+        if (GetEventParameter(inEvent, kEventParamPLEventQueue,
+                              typeUInt32, NULL, sizeof(PREventQueue*), NULL,
+                              &queue) == noErr)
+        {
+            PL_ProcessPendingEvents(queue);
+            return noErr;
+        }
+    }
+    return eventNotHandledErr;
+}
+
+static pascal Boolean _md_CarbonEventComparator(EventRef inEvent,
+                                                void *inCompareData)
+{
+    Boolean match = false;
+
+    if (GetEventClass(inEvent) == kEventClassPL &&
+        GetEventKind(inEvent) == kEventProcessPLEvents)
+    {
+        PREventQueue *queue;
+        match = ((GetEventParameter(inEvent, kEventParamPLEventQueue,
+                                    typeUInt32, NULL, sizeof(PREventQueue*), NULL,
+                                    &queue) == noErr) && (queue == inCompareData));
+    }
+    return match;
+}
+
+#endif /* defined(MAC_USE_CARBON_EVENT) */
+
+#if defined(XP_MACOSX)
+static void _md_CreateEventQueue( PLEventQueue *eventQueue )
+{
+#if defined(MAC_USE_CFRUNLOOPSOURCE)
+    CFRunLoopSourceContext sourceContext = { 0 };
+    sourceContext.version = 0;
+    sourceContext.info = (void*)eventQueue;
+    sourceContext.perform = _md_EventReceiverProc;
+
+    /* make a run loop source */
+    eventQueue->mRunLoopSource = CFRunLoopSourceCreate(kCFAllocatorDefault, 0 /* order */, &sourceContext);
+    PR_ASSERT(eventQueue->mRunLoopSource);
+
+    eventQueue->mMainRunLoop = CFRunLoopGetCurrent();
+    CFRetain(eventQueue->mMainRunLoop);
+
+    /* and add it to the run loop */
+    CFRunLoopAddSource(eventQueue->mMainRunLoop, eventQueue->mRunLoopSource, kCFRunLoopCommonModes);
+
+    /* Add it again but with a unique mode name so we can acknowledge it
+       without processing any other message sources. */
+    {                                                                                                   /* vbox */
+        char szModeName[80];                                                                            /* vbox */
+        snprintf(szModeName, sizeof(szModeName), "VBoxXPCOMQueueMode-%p", eventQueue);                  /* vbox */
+        eventQueue->mRunLoopModeStr = CFStringCreateWithCString(kCFAllocatorDefault,                    /* vbox */
+                                                                szModeName, kCFStringEncodingASCII);    /* vbox */
+        CFRunLoopAddSource(eventQueue->mMainRunLoop,                                                    /* vbox */
+                           eventQueue->mRunLoopSource, eventQueue->mRunLoopModeStr);                    /* vbox */
+    }                                                                                                   /* vbox */
+
+#elif defined(MAC_USE_CARBON_EVENT)
+    eventQueue->eventHandlerUPP = NewEventHandlerUPP(_md_EventReceiverProc);
+    PR_ASSERT(eventQueue->eventHandlerUPP);
+    if (eventQueue->eventHandlerUPP)
+    {
+      EventTypeSpec     eventType;
+
+      eventType.eventClass = kEventClassPL;
+      eventType.eventKind  = kEventProcessPLEvents;
+
+      InstallApplicationEventHandler(eventQueue->eventHandlerUPP, 1, &eventType,
+                                     eventQueue, &eventQueue->eventHandlerRef);
+      PR_ASSERT(eventQueue->eventHandlerRef);
+    }
+#endif
+} /* end _md_CreateEventQueue() */
+#endif /* defined(XP_MACOSX) */
+
+/* extra functions for unix */
+
+#if defined(XP_UNIX) && !defined(XP_MACOSX)
+
+PR_IMPLEMENT(PRInt32)
+PL_ProcessEventsBeforeID(PLEventQueue *aSelf, unsigned long aID)
+{
+    PRInt32 count = 0;
+    PRInt32 fullCount;
+
+    if (aSelf == NULL)
+        return -1;
+
+    PR_EnterMonitor(aSelf->monitor);
+
+    if (aSelf->processingEvents) {
+        PR_ExitMonitor(aSelf->monitor);
+        return 0;
+    }
+
+    aSelf->processingEvents = PR_TRUE;
+
+    /* Only process the events that are already in the queue, and
+     * not any new events that get added. Do this by counting the
+     * number of events currently in the queue
+     */
+    fullCount = _pl_GetEventCount(aSelf);
+    PR_LOG(event_lm, PR_LOG_DEBUG,
+           ("$$$ fullCount is %d id is %ld\n", fullCount, aID));
+
+    if (fullCount == 0) {
+        aSelf->processingEvents = PR_FALSE;
+        PR_ExitMonitor(aSelf->monitor);
+        return 0;
+    }
+
+    PR_ExitMonitor(aSelf->monitor);
+
+    while (fullCount-- > 0) {
+        /* peek at the next event */
+        PLEvent *event;
+        event = PR_EVENT_PTR(aSelf->queue.next);
+        if (event == NULL)
+            break;
+        PR_LOG(event_lm, PR_LOG_DEBUG, ("$$$ processing event %ld\n",
+                                        event->id));
+        if (event->id >= aID) {
+            PR_LOG(event_lm, PR_LOG_DEBUG, ("$$$ skipping event and breaking"));
+            break;
+        }
+
+        event = PL_GetEvent(aSelf);
+        PL_HandleEvent(event);
+        PR_LOG(event_lm, PR_LOG_DEBUG, ("$$$ done processing event"));
+        count++;
+    }
+
+    PR_EnterMonitor(aSelf->monitor);
+
+    /* if full count still had items left then there's still items left
+       in the queue.  Let the native notify token stay. */
+
+    if (aSelf->type == EventQueueIsNative) {
+        fullCount = _pl_GetEventCount(aSelf);
+
+        if (fullCount <= 0) {
+            _pl_AcknowledgeNativeNotify(aSelf);
+            aSelf->notified = PR_FALSE;
+        }
+    }
+
+    aSelf->processingEvents = PR_FALSE;
+
+    PR_ExitMonitor(aSelf->monitor);
+
+    return count;
+}
+
+PR_IMPLEMENT(void)
+PL_RegisterEventIDFunc(PLEventQueue *aSelf, PLGetEventIDFunc aFunc,
+                       void *aClosure)
+{
+    aSelf->idFunc = aFunc;
+    aSelf->idFuncClosure = aClosure;
+}
+
+PR_IMPLEMENT(void)
+PL_UnregisterEventIDFunc(PLEventQueue *aSelf)
+{
+    aSelf->idFunc = 0;
+    aSelf->idFuncClosure = 0;
+}
+
+#endif /* defined(XP_UNIX) && !defined(XP_MACOSX) */
+
+/* --- end plevent.c --- */