summaryrefslogtreecommitdiffstats
path: root/win/tclWinNotify.c
blob: b7bb17d38ab61f7e036dd50d4b2f382fe1519ecd (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
/* 
 * tclWinNotify.c --
 *
 *	This file contains Windows-specific procedures for the notifier,
 *	which is the lowest-level part of the Tcl event loop.  This file
 *	works together with ../generic/tclNotify.c.
 *
 * Copyright (c) 1995-1997 Sun Microsystems, Inc.
 *
 * See the file "license.terms" for information on usage and redistribution
 * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 *
 * RCS: @(#) $Id: tclWinNotify.c,v 1.11 2003/01/16 19:02:00 mdejong Exp $
 */

#include "tclWinInt.h"

/*
 * The follwing static indicates whether this module has been initialized.
 */

#define INTERVAL_TIMER 1	/* Handle of interval timer. */

#define WM_WAKEUP WM_USER	/* Message that is send by
				 * Tcl_AlertNotifier. */
/*
 * The following static structure contains the state information for the
 * Windows implementation of the Tcl notifier.  One of these structures
 * is created for each thread that is using the notifier.  
 */

typedef struct ThreadSpecificData {
    CRITICAL_SECTION crit;	/* Monitor for this notifier. */
    DWORD thread;		/* Identifier for thread associated with this
				 * notifier. */
    HANDLE event;		/* Event object used to wake up the notifier
				 * thread. */
    int pending;		/* Alert message pending, this field is
				 * locked by the notifierMutex. */
    HWND hwnd;			/* Messaging window. */
    int timeout;		/* Current timeout value. */
    int timerActive;		/* 1 if interval timer is running. */
} ThreadSpecificData;

static Tcl_ThreadDataKey dataKey;

extern TclStubs tclStubs;
/*
 * The following static indicates the number of threads that have
 * initialized notifiers.  It controls the lifetime of the TclNotifier
 * window class.
 *
 * You must hold the notifierMutex lock before accessing this variable.
 */

static int notifierCount = 0;
TCL_DECLARE_MUTEX(notifierMutex)

/*
 * Static routines defined in this file.
 */

static LRESULT CALLBACK	NotifierProc(HWND hwnd, UINT message,
			    WPARAM wParam, LPARAM lParam);


/*
 *----------------------------------------------------------------------
 *
 * Tcl_InitNotifier --
 *
 *	Initializes the platform specific notifier state.
 *
 * Results:
 *	Returns a handle to the notifier state for this thread..
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

ClientData
Tcl_InitNotifier()
{
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
    WNDCLASS class;

    /*
     * Register Notifier window class if this is the first thread to
     * use this module.
     */

    Tcl_MutexLock(&notifierMutex);
    if (notifierCount == 0) {
	class.style = 0;
	class.cbClsExtra = 0;
	class.cbWndExtra = 0;
	class.hInstance = TclWinGetTclInstance();
	class.hbrBackground = NULL;
	class.lpszMenuName = NULL;
	class.lpszClassName = "TclNotifier";
	class.lpfnWndProc = NotifierProc;
	class.hIcon = NULL;
	class.hCursor = NULL;

	if (!RegisterClassA(&class)) {
	    panic("Unable to register TclNotifier window class");
	}
    }
    notifierCount++;
    Tcl_MutexUnlock(&notifierMutex);

    tsdPtr->pending = 0;
    tsdPtr->timerActive = 0;

    InitializeCriticalSection(&tsdPtr->crit);

    tsdPtr->hwnd = NULL;
    tsdPtr->thread = GetCurrentThreadId();
    tsdPtr->event = CreateEvent(NULL, TRUE /* manual */,
	    FALSE /* !signaled */, NULL);

    return (ClientData) tsdPtr;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_FinalizeNotifier --
 *
 *	This function is called to cleanup the notifier state before
 *	a thread is terminated.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	May dispose of the notifier window and class.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_FinalizeNotifier(clientData)
    ClientData clientData;	/* Pointer to notifier data. */
{
    ThreadSpecificData *tsdPtr = (ThreadSpecificData *) clientData;

    /*
     * Only finalize the notifier if a notifier was installed in the
     * current thread; there is a route in which this is not
     * guaranteed to be true (when tclWin32Dll.c:DllMain() is called
     * with the flag DLL_PROCESS_DETACH by the OS, which could be
     * doing so from a thread that's never previously been involved
     * with Tcl, e.g. the task manager) so this check is important.
     *
     * Fixes Bug #217982 reported by Hugh Vu and Gene Leache.
     */
    if (tsdPtr == NULL) {
	return;
    }

    DeleteCriticalSection(&tsdPtr->crit);
    CloseHandle(tsdPtr->event);

    /*
     * Clean up the timer and messaging window for this thread.
     */

    if (tsdPtr->hwnd) {
	KillTimer(tsdPtr->hwnd, INTERVAL_TIMER);
	DestroyWindow(tsdPtr->hwnd);
    }

    /*
     * If this is the last thread to use the notifier, unregister
     * the notifier window class.
     */

    Tcl_MutexLock(&notifierMutex);
    notifierCount--;
    if (notifierCount == 0) {
	UnregisterClassA("TclNotifier", TclWinGetTclInstance());
    }
    Tcl_MutexUnlock(&notifierMutex);
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_AlertNotifier --
 *
 *	Wake up the specified notifier from any thread. This routine
 *	is called by the platform independent notifier code whenever
 *	the Tcl_ThreadAlert routine is called.  This routine is
 *	guaranteed not to be called on a given notifier after
 *	Tcl_FinalizeNotifier is called for that notifier.  This routine
 *	is typically called from a thread other than the notifier's
 *	thread.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Sends a message to the messaging window for the notifier
 *	if there isn't already one pending.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_AlertNotifier(clientData)
    ClientData clientData;	/* Pointer to thread data. */
{
    ThreadSpecificData *tsdPtr = (ThreadSpecificData *) clientData;

    /*
     * Note that we do not need to lock around access to the hwnd
     * because the race condition has no effect since any race condition
     * implies that the notifier thread is already awake.
     */

    if (tsdPtr->hwnd) {
	/*
	 * We do need to lock around access to the pending flag.
	 */

	EnterCriticalSection(&tsdPtr->crit);
	if (!tsdPtr->pending) {
	    PostMessage(tsdPtr->hwnd, WM_WAKEUP, 0, 0);
	}
	tsdPtr->pending = 1;
	LeaveCriticalSection(&tsdPtr->crit);
    } else {
	SetEvent(tsdPtr->event);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_SetTimer --
 *
 *	This procedure sets the current notifier timer value.  The
 *	notifier will ensure that Tcl_ServiceAll() is called after
 *	the specified interval, even if no events have occurred.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Replaces any previous timer.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_SetTimer(
    Tcl_Time *timePtr)		/* Maximum block time, or NULL. */
{
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
    UINT timeout;

    /*
     * Allow the notifier to be hooked.  This may not make sense
     * on Windows, but mirrors the UNIX hook.
     */

    if (tclStubs.tcl_SetTimer != Tcl_SetTimer) {
	tclStubs.tcl_SetTimer(timePtr);
	return;
    }

    /*
     * We only need to set up an interval timer if we're being called
     * from an external event loop.  If we don't have a window handle
     * then we just return immediately and let Tcl_WaitForEvent handle
     * timeouts.
     */

    if (!tsdPtr->hwnd) {
	return;
    }

    if (!timePtr) {
	timeout = 0;
    } else {
	/*
	 * Make sure we pass a non-zero value into the timeout argument.
	 * Windows seems to get confused by zero length timers.
	 */

	timeout = timePtr->sec * 1000 + timePtr->usec / 1000;
	if (timeout == 0) {
	    timeout = 1;
	}
    }
    tsdPtr->timeout = timeout;
    if (timeout != 0) {
	tsdPtr->timerActive = 1;
	SetTimer(tsdPtr->hwnd, INTERVAL_TIMER,
		    (unsigned long) tsdPtr->timeout, NULL);
    } else {
	tsdPtr->timerActive = 0;
	KillTimer(tsdPtr->hwnd, INTERVAL_TIMER);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_ServiceModeHook --
 *
 *	This function is invoked whenever the service mode changes.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	If this is the first time the notifier is set into
 *	TCL_SERVICE_ALL, then the communication window is created.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_ServiceModeHook(mode)
    int mode;			/* Either TCL_SERVICE_ALL, or
				 * TCL_SERVICE_NONE. */
{
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);

    /*
     * If this is the first time that the notifier has been used from a
     * modal loop, then create a communication window.  Note that after
     * this point, the application needs to service events in a timely
     * fashion or Windows will hang waiting for the window to respond
     * to synchronous system messages.  At some point, we may want to
     * consider destroying the window if we leave the modal loop, but
     * for now we'll leave it around.
     */

    if (mode == TCL_SERVICE_ALL && !tsdPtr->hwnd) {
	tsdPtr->hwnd = CreateWindowA("TclNotifier", "TclNotifier", WS_TILED,
		0, 0, 0, 0, NULL, NULL, TclWinGetTclInstance(), NULL);
	/*
	 * Send an initial message to the window to ensure that we wake up the
	 * notifier once we get into the modal loop.  This will force the
	 * notifier to recompute the timeout value and schedule a timer
	 * if one is needed.
	 */

	Tcl_AlertNotifier((ClientData)tsdPtr);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * NotifierProc --
 *
 *	This procedure is invoked by Windows to process events on
 *	the notifier window.  Messages will be sent to this window
 *	in response to external timer events or calls to
 *	TclpAlertTsdPtr->
 *
 * Results:
 *	A standard windows result.
 *
 * Side effects:
 *	Services any pending events.
 *
 *----------------------------------------------------------------------
 */

static LRESULT CALLBACK
NotifierProc(
    HWND hwnd,
    UINT message,
    WPARAM wParam,
    LPARAM lParam)
{
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);

    if (message == WM_WAKEUP) {
	EnterCriticalSection(&tsdPtr->crit);
	tsdPtr->pending = 0;
	LeaveCriticalSection(&tsdPtr->crit);
    } else if (message != WM_TIMER) {
	return DefWindowProc(hwnd, message, wParam, lParam);
    }
	
    /*
     * Process all of the runnable events.
     */

    Tcl_ServiceAll();
    return 0;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_WaitForEvent --
 *
 *	This function is called by Tcl_DoOneEvent to wait for new
 *	events on the message queue.  If the block time is 0, then
 *	Tcl_WaitForEvent just polls the event queue without blocking.
 *
 * Results:
 *	Returns -1 if a WM_QUIT message is detected, returns 1 if
 *	a message was dispatched, otherwise returns 0.
 *
 * Side effects:
 *	Dispatches a message to a window procedure, which could do
 *	anything.
 *
 *----------------------------------------------------------------------
 */

int
Tcl_WaitForEvent(
    Tcl_Time *timePtr)		/* Maximum block time, or NULL. */
{
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
    MSG msg;
    DWORD timeout, result;
    int status;

    /*
     * Allow the notifier to be hooked.  This may not make
     * sense on windows, but mirrors the UNIX hook.
     */

    if (tclStubs.tcl_WaitForEvent != Tcl_WaitForEvent) {
	return tclStubs.tcl_WaitForEvent(timePtr);
    }

    /*
     * Compute the timeout in milliseconds.
     */

    if (timePtr) {
	timeout = timePtr->sec * 1000 + timePtr->usec / 1000;
    } else {
	timeout = INFINITE;
    }

    /*
     * Check to see if there are any messages in the queue before waiting
     * because MsgWaitForMultipleObjects will not wake up if there are events
     * currently sitting in the queue.
     */

    if (!PeekMessage(&msg, NULL, 0, 0, PM_NOREMOVE)) {
	/*
	 * Wait for something to happen (a signal from another thread, a
	 * message, or timeout).
	 */

	result = MsgWaitForMultipleObjects(1, &tsdPtr->event, FALSE, timeout,
		QS_ALLINPUT);
    }

    /*
     * Check to see if there are any messages to process.
     */

    if (PeekMessage(&msg, NULL, 0, 0, PM_NOREMOVE)) {
	/*
	 * Retrieve and dispatch the first message.
	 */

	result = GetMessage(&msg, NULL, 0, 0);
	if (result == 0) {
	    /*
	     * We received a request to exit this thread (WM_QUIT), so
	     * propagate the quit message and start unwinding.
	     */

	    PostQuitMessage((int) msg.wParam);
	    status = -1;
	} else if (result == -1) {
	    /*
	     * We got an error from the system.  I have no idea why this would
	     * happen, so we'll just unwind.
	     */

	    status = -1;
	} else {
	    TranslateMessage(&msg);
	    DispatchMessage(&msg);
	    status = 1;
	}
    } else {
	status = 0;
    }

    ResetEvent(tsdPtr->event);
    return status;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_Sleep --
 *
 *	Delay execution for the specified number of milliseconds.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Time passes.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_Sleep(ms)
    int ms;			/* Number of milliseconds to sleep. */
{
    /*
     * Simply calling 'Sleep' for the requisite number of milliseconds
     * can make the process appear to wake up early because it isn't
     * synchronized with the CPU performance counter that is used in
     * tclWinTime.c.  This behavior is probably benign, but messes
     * up some of the corner cases in the test suite.  We get around
     * this problem by repeating the 'Sleep' call as many times
     * as necessary to make the clock advance by the requisite amount.
     */

    Tcl_Time now;		/* Current wall clock time */
    Tcl_Time desired;		/* Desired wakeup time */
    DWORD sleepTime = ms;	/* Time to sleep */

    Tcl_GetTime( &now );
    desired.sec = now.sec + ( ms / 1000 );
    desired.usec = now.usec + 1000 * ( ms % 1000 );
    if ( desired.usec > 1000000 ) {
	++desired.sec;
	desired.usec -= 1000000;
    }
	
    for ( ; ; ) {
	Sleep( sleepTime );
	Tcl_GetTime( &now );
	if ( now.sec > desired.sec ) {
	    break;
	} else if ( ( now.sec == desired.sec )
	     && ( now.usec >= desired.usec ) ) {
	    break;
	}
	sleepTime = ( ( 1000 * ( desired.sec - now.sec ) )
		      + ( ( desired.usec - now.usec ) / 1000 ) );
    }

}