/*
 * tclUnixNotfy.c --
 *
 *	This file contains the implementation of the select()-based

 *	Unix-specific 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.
 */


#include "tclInt.h"
#ifndef HAVE_COREFOUNDATION	/* Darwin/Mac OS X CoreFoundation notifier is
				 * in tclMacOSXNotify.c */
#include <signal.h>

/*
 * This structure is used to keep track of the notifier info for a registered

				 * to Tcl_CreateFileHandler. */
    SelectMasks readyMasks;	/* This array reflects the readable/writable
				 * conditions that were found to exist by the
				 * last call to select. */
    int numFdBits;		/* Number of valid bits in checkMasks (one
				 * more than highest fd for which
				 * Tcl_WatchFile has been called). */
#ifdef TCL_THREADS
    int onList;			/* True if it is in this list */
    unsigned int pollState;	/* pollState is used to implement a polling
				 * handshake between each thread and the
				 * notifier thread. Bits defined below. */
    struct ThreadSpecificData *nextPtr, *prevPtr;
				/* All threads that are currently waiting on
				 * an event have their ThreadSpecificData

    int useMonoTime;		/* When true use CLOCK_MONOTONIC */
#endif
#endif /* __CYGWIN__ */
    int waitCVinitialized;	/* Variable to flag initialization of the structure */
    int eventReady;		/* True if an event is ready to be processed.
				 * Used as condition flag together with waitCV
				 * above. */
#endif /* TCL_THREADS */
} ThreadSpecificData;

static Tcl_ThreadDataKey dataKey;

#ifdef TCL_THREADS
/*
 * The following static indicates the number of threads that have initialized
 * notifiers.
 *
 * You must hold the notifierMutex lock before accessing this variable.
 */

/*
 * This is the thread ID of the notifier thread that does select.
 */

static Tcl_ThreadId notifierThread;

#endif /* TCL_THREADS */

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


#ifdef TCL_THREADS





static TCL_NORETURN void NotifierThreadProc(ClientData clientData);
#if defined(HAVE_PTHREAD_ATFORK)
static int	atForkInit = 0;
static void	AtForkChild(void);
#endif /* HAVE_PTHREAD_ATFORK */
#endif /* TCL_THREADS */
static int	FileHandlerEventProc(Tcl_Event *evPtr, int flags);

/*
 * Import of Windows API when building threaded with Cygwin.
 */

#if defined(TCL_THREADS) && defined(__CYGWIN__)
typedef struct {
    void *hwnd;
    unsigned int *message;
    int wParam;
    int lParam;
    int time;
    int x;
    int y;
} MSG;

typedef struct {
    unsigned int style;
    void *lpfnWndProc;
    int cbClsExtra;
    int cbWndExtra;
    void *hInstance;
    void *hIcon;
    void *hCursor;
    void *hbrBackground;
    void *lpszMenuName;
    const void *lpszClassName;
} WNDCLASS;

extern void __stdcall	CloseHandle(void *);
extern void *__stdcall	CreateEventW(void *, unsigned char, unsigned char,
			    void *);
extern void * __stdcall	CreateWindowExW(void *, const void *, const void *,
			    DWORD, int, int, int, int, void *, void *, void *, void *);
extern DWORD __stdcall	DefWindowProcW(void *, int, void *, void *);
extern unsigned char __stdcall	DestroyWindow(void *);
extern int __stdcall	DispatchMessageW(const MSG *);
extern unsigned char __stdcall	GetMessageW(MSG *, void *, int, int);
extern void __stdcall	MsgWaitForMultipleObjects(DWORD, void *,
			    unsigned char, DWORD, DWORD);
extern unsigned char __stdcall	PeekMessageW(MSG *, void *, int, int, int);
extern unsigned char __stdcall	PostMessageW(void *, unsigned int, void *,
				    void *);
extern void __stdcall	PostQuitMessage(int);
extern void *__stdcall	RegisterClassW(const WNDCLASS *);
extern unsigned char __stdcall	ResetEvent(void *);
extern unsigned char __stdcall	TranslateMessage(const MSG *);

/*
 * Threaded-cygwin specific constants and functions in this file:
 */

static const WCHAR className[] = L"TclNotifier";
static DWORD __stdcall	NotifierProc(void *hwnd, unsigned int message,
			    void *wParam, void *lParam);
#endif /* TCL_THREADS && __CYGWIN__ */

#if TCL_THREADS
/*
 *----------------------------------------------------------------------
 *
 * StartNotifierThread --
 *
 *	Start a notfier thread and wait for the notifier pipe to be created.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Running Thread.
 *
 *----------------------------------------------------------------------
 */

static void
StartNotifierThread(const char *proc)

{
    if (!notifierThreadRunning) {
	pthread_mutex_lock(&notifierInitMutex);
	if (!notifierThreadRunning) {
	    if (TclpThreadCreate(&notifierThread, NotifierThreadProc, NULL,
		    TCL_THREAD_STACK_DEFAULT, TCL_THREAD_JOINABLE) != TCL_OK) {
		Tcl_Panic("%s: unable to start notifier thread", proc);
	    }

	    pthread_mutex_lock(&notifierMutex);

	    /*
	     * Wait for the notifier pipe to be created.
	     */

	    while (triggerPipe < 0) {
		pthread_cond_wait(&notifierCV, &notifierMutex);
	    }
	    pthread_mutex_unlock(&notifierMutex);

	    notifierThreadRunning = 1;
	}
	pthread_mutex_unlock(&notifierInitMutex);
    }
}
#endif /* TCL_THREADS */

/*
 *----------------------------------------------------------------------
 *
 * Tcl_InitNotifier --
 *
 *	Initializes the platform specific notifier state.

Tcl_InitNotifier(void)
{
    if (tclNotifierHooks.initNotifierProc) {
	return tclNotifierHooks.initNotifierProc();
    } else {
	ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);

#ifdef TCL_THREADS
	tsdPtr->eventReady = 0;

	/*
	 * Initialize thread specific condition variable for this thread.
	 */
	if (tsdPtr->waitCVinitialized == 0) {
#ifdef __CYGWIN__

	}
#endif /* HAVE_PTHREAD_ATFORK */

	notifierCount++;

	pthread_mutex_unlock(&notifierInitMutex);

#endif /* TCL_THREADS */
	return tsdPtr;
    }
}

/*
 *----------------------------------------------------------------------
 *

Tcl_FinalizeNotifier(
    ClientData clientData)		/* Not used. */
{
    if (tclNotifierHooks.finalizeNotifierProc) {
	tclNotifierHooks.finalizeNotifierProc(clientData);
	return;
    } else {
#ifdef TCL_THREADS
	ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);

	pthread_mutex_lock(&notifierInitMutex);
	notifierCount--;

	/*
	 * If this is the last thread to use the notifier, close the notifier

	CloseHandle(tsdPtr->event);
#else /* __CYGWIN__ */
	pthread_cond_destroy(&tsdPtr->waitCV);
#endif /* __CYGWIN__ */
	tsdPtr->waitCVinitialized = 0;

	pthread_mutex_unlock(&notifierInitMutex);
#endif /* TCL_THREADS */
    }
}

/*
 *----------------------------------------------------------------------
 *
 * 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.
 *
 * Results:
 *	None.
 *
 * Side effects:

 *	Signals the notifier condition variable for the specified notifier.





 *
 *----------------------------------------------------------------------
 */

void
Tcl_AlertNotifier(
    ClientData clientData)
{
    if (tclNotifierHooks.alertNotifierProc) {
	tclNotifierHooks.alertNotifierProc(clientData);
	return;
    } else {
#ifdef TCL_THREADS
	ThreadSpecificData *tsdPtr = clientData;

	pthread_mutex_lock(&notifierMutex);
	tsdPtr->eventReady = 1;

#   ifdef __CYGWIN__
	PostMessageW(tsdPtr->hwnd, 1024, 0, 0);
#   else
	pthread_cond_broadcast(&tsdPtr->waitCV);
#   endif /* __CYGWIN__ */
	pthread_mutex_unlock(&notifierMutex);


#endif /* TCL_THREADS */




    }































































}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_SetTimer --
 *
 *	This function sets the current notifier timer value. This interface is
 *	not implemented in this notifier because we are always running inside
 *	of Tcl_DoOneEvent.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_SetTimer(
    const Tcl_Time *timePtr)		/* Timeout value, may be NULL. */
{
    if (tclNotifierHooks.setTimerProc) {
	tclNotifierHooks.setTimerProc(timePtr);
	return;
    } else {
	/*
	 * The interval timer doesn't do anything in this implementation,
	 * because the only event loop is via Tcl_DoOneEvent, which passes
	 * timeout values to Tcl_WaitForEvent.
	 */
    }
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_ServiceModeHook --
 *
 *	This function is invoked whenever the service mode changes.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_ServiceModeHook(
    int mode)			/* Either TCL_SERVICE_ALL, or
				 * TCL_SERVICE_NONE. */
{
    if (tclNotifierHooks.serviceModeHookProc) {
	tclNotifierHooks.serviceModeHookProc(mode);
	return;
    } else if (mode == TCL_SERVICE_ALL) {

#if TCL_THREADS
	StartNotifierThread("Tcl_ServiceModeHook");
#endif
    }
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_CreateFileHandler --
 *
 *	This function registers a file handler with the select notifier.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Creates a new file handler structure.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_CreateFileHandler(
    int fd,			/* Handle of stream to watch. */
    int mask,			/* OR'ed combination of TCL_READABLE,
				 * TCL_WRITABLE, and TCL_EXCEPTION: indicates
				 * conditions under which proc should be
				 * called. */
    Tcl_FileProc *proc,		/* Function to call for each selected
				 * event. */
    ClientData clientData)	/* Arbitrary data to pass to proc. */
{
    if (tclNotifierHooks.createFileHandlerProc) {
	tclNotifierHooks.createFileHandlerProc(fd, mask, proc, clientData);
	return;
    } else {
	ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
	FileHandler *filePtr;

	for (filePtr = tsdPtr->firstFileHandlerPtr; filePtr != NULL;
		filePtr = filePtr->nextPtr) {
	    if (filePtr->fd == fd) {
		break;
	    }
	}
	if (filePtr == NULL) {
	    filePtr = ckalloc(sizeof(FileHandler));
	    filePtr->fd = fd;
	    filePtr->readyMask = 0;
	    filePtr->nextPtr = tsdPtr->firstFileHandlerPtr;
	    tsdPtr->firstFileHandlerPtr = filePtr;
	}
	filePtr->proc = proc;
	filePtr->clientData = clientData;
	filePtr->mask = mask;

	/*
	 * Update the check masks for this file.
	 */

	if (mask & TCL_READABLE) {
	    FD_SET(fd, &tsdPtr->checkMasks.readable);
	} else {
	    FD_CLR(fd, &tsdPtr->checkMasks.readable);
	}
	if (mask & TCL_WRITABLE) {
	    FD_SET(fd, &tsdPtr->checkMasks.writable);
	} else {
	    FD_CLR(fd, &tsdPtr->checkMasks.writable);
	}
	if (mask & TCL_EXCEPTION) {
	    FD_SET(fd, &tsdPtr->checkMasks.exception);
	} else {
	    FD_CLR(fd, &tsdPtr->checkMasks.exception);
	}
	if (tsdPtr->numFdBits <= fd) {
	    tsdPtr->numFdBits = fd+1;
	}
    }
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_DeleteFileHandler --
 *
 *	Cancel a previously-arranged callback arrangement for a file.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	If a callback was previously registered on file, remove it.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_DeleteFileHandler(
    int fd)			/* Stream id for which to remove callback
				 * function. */
{
    if (tclNotifierHooks.deleteFileHandlerProc) {
	tclNotifierHooks.deleteFileHandlerProc(fd);
	return;
    } else {
	FileHandler *filePtr, *prevPtr;
	int i;
	ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);

	/*
	 * Find the entry for the given file (and return if there isn't one).
	 */

	for (prevPtr = NULL, filePtr = tsdPtr->firstFileHandlerPtr; ;
		prevPtr = filePtr, filePtr = filePtr->nextPtr) {
	    if (filePtr == NULL) {
		return;
	    }
	    if (filePtr->fd == fd) {
		break;
	    }
	}

	/*
	 * Update the check masks for this file.
	 */

	if (filePtr->mask & TCL_READABLE) {
	    FD_CLR(fd, &tsdPtr->checkMasks.readable);
	}
	if (filePtr->mask & TCL_WRITABLE) {
	    FD_CLR(fd, &tsdPtr->checkMasks.writable);
	}
	if (filePtr->mask & TCL_EXCEPTION) {
	    FD_CLR(fd, &tsdPtr->checkMasks.exception);
	}

	/*
	 * Find current max fd.
	 */

	if (fd+1 == tsdPtr->numFdBits) {
	    int numFdBits = 0;

	    for (i = fd-1; i >= 0; i--) {
		if (FD_ISSET(i, &tsdPtr->checkMasks.readable)
			|| FD_ISSET(i, &tsdPtr->checkMasks.writable)
			|| FD_ISSET(i, &tsdPtr->checkMasks.exception)) {
		    numFdBits = i+1;
		    break;
		}
	    }
	    tsdPtr->numFdBits = numFdBits;
	}

	/*
	 * Clean up information in the callback record.
	 */

	if (prevPtr == NULL) {
	    tsdPtr->firstFileHandlerPtr = filePtr->nextPtr;
	} else {
	    prevPtr->nextPtr = filePtr->nextPtr;
	}
	ckfree(filePtr);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * FileHandlerEventProc --

	    filePtr->proc(filePtr->clientData, mask);
	}
	break;
    }
    return 1;
}

#if defined(TCL_THREADS) && defined(__CYGWIN__)

static DWORD __stdcall
NotifierProc(
    void *hwnd,
    unsigned int message,
    void *wParam,
    void *lParam)

     * Process all of the runnable events.
     */

    tsdPtr->eventReady = 1;
    Tcl_ServiceAll();
    return 0;
}
#endif /* TCL_THREADS && __CYGWIN__ */

/*
 *----------------------------------------------------------------------
 *
 * Tcl_WaitForEvent --
 *
 *	This function is called by Tcl_DoOneEvent to wait for new events on

{
    if (tclNotifierHooks.waitForEventProc) {
	return tclNotifierHooks.waitForEventProc(timePtr);
    } else {
	FileHandler *filePtr;
	int mask;
	Tcl_Time vTime;
#ifdef TCL_THREADS
	int waitForFiles;
#   ifdef __CYGWIN__
	MSG msg;
#   endif /* __CYGWIN__ */
#else
	/*
	 * Impl. notes: timeout & timeoutPtr are used if, and only if threads
	 * are not enabled. They are the arguments for the regular select()
	 * used when the core is not thread-enabled.
	 */

	struct timeval timeout, *timeoutPtr;
	int numFound;
#endif /* TCL_THREADS */
	ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);

	/*
	 * Set up the timeout structure. Note that if there are no events to
	 * check for, we return with a negative result rather than blocking
	 * forever.
	 */

	if (timePtr != NULL) {
	    /*
	     * TIP #233 (Virtualized Time). Is virtual time in effect? And do
	     * we actually have something to scale? If yes to both then we
	     * call the handler to do this scaling.
	     */

	    if (timePtr->sec != 0 || timePtr->usec != 0) {
		vTime = *timePtr;
		tclScaleTimeProcPtr(&vTime, tclTimeClientData);
		timePtr = &vTime;
	    }
#ifndef TCL_THREADS
	    timeout.tv_sec = timePtr->sec;
	    timeout.tv_usec = timePtr->usec;
	    timeoutPtr = &timeout;
	} else if (tsdPtr->numFdBits == 0) {
	    /*
	     * If there are no threads, no timeout, and no fds registered,
	     * then there are no events possible and we must avoid deadlock.
	     * Note that this is not entirely correct because there might be a
	     * signal that could interrupt the select call, but we don't
	     * handle that case if we aren't using threads.
	     */

	    return -1;
	} else {
	    timeoutPtr = NULL;
#endif /* !TCL_THREADS */
	}

#ifdef TCL_THREADS
	/*
	 * Start notifier thread and place this thread on the list of
	 * interested threads, signal the notifier thread, and wait for a
	 * response or a timeout.
	 */
	StartNotifierThread("Tcl_WaitForEvent");

	    tsdPtr->onList = 0;
	    if ((write(triggerPipe, "", 1) == -1) && (errno != EAGAIN)) {
		Tcl_Panic("Tcl_WaitForEvent: %s",
			"unable to write to triggerPipe");
	    }
	}

#else
	tsdPtr->readyMasks = tsdPtr->checkMasks;
	numFound = select(tsdPtr->numFdBits, &tsdPtr->readyMasks.readable,
		&tsdPtr->readyMasks.writable, &tsdPtr->readyMasks.exception,
		timeoutPtr);

	/*
	 * Some systems don't clear the masks after an error, so we have to do
	 * it here.
	 */

	if (numFound == -1) {
	    FD_ZERO(&tsdPtr->readyMasks.readable);
	    FD_ZERO(&tsdPtr->readyMasks.writable);
	    FD_ZERO(&tsdPtr->readyMasks.exception);
	}
#endif /* TCL_THREADS */

	/*
	 * Queue all detected file events before returning.
	 */

	for (filePtr = tsdPtr->firstFileHandlerPtr; (filePtr != NULL);
		filePtr = filePtr->nextPtr) {
	    mask = 0;

		fileEvPtr->header.proc = FileHandlerEventProc;
		fileEvPtr->fd = filePtr->fd;
		Tcl_QueueEvent((Tcl_Event *) fileEvPtr, TCL_QUEUE_TAIL);
	    }
	    filePtr->readyMask = mask;
	}
#ifdef TCL_THREADS
	pthread_mutex_unlock(&notifierMutex);
#endif /* TCL_THREADS */
	return 0;
    }
}

#ifdef TCL_THREADS
/*
 *----------------------------------------------------------------------
 *
 * NotifierThreadProc --
 *
 *	This routine is the initial (and only) function executed by the
 *	special notifier thread. Its job is to wait for file descriptors to

    if (notifierThreadRunning == 1) {
	pthread_cond_destroy(&notifierCV);
    }
    pthread_mutex_init(&notifierInitMutex, NULL);
    pthread_mutex_init(&notifierMutex, NULL);
    pthread_cond_init(&notifierCV, NULL);





    /*
     * notifierThreadRunning == 1: thread is running, (there might be data in notifier lists)

     * atForkInit == 0: InitNotifier was never called
     * notifierCount != 0: unbalanced  InitNotifier() / FinalizeNotifier calls
     * waitingListPtr != 0: there are threads currently waiting for events.
     */

    if (atForkInit == 1) {

	notifierCount = 0;
	if (notifierThreadRunning == 1) {
	    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
	    notifierThreadRunning = 0;

	    close(triggerPipe);
	    triggerPipe = -1;




	    /*
	     * The waitingListPtr might contain event info from multiple
	     * threads, which are invalid here, so setting it to NULL is not
	     * unreasonable.
	     */
	    waitingListPtr = NULL;

	    /*
	     * The tsdPtr from before the fork is copied as well.  But since
	     * we are paranoic, we don't trust its condvar and reset it.
	     */
#ifdef __CYGWIN__
	    DestroyWindow(tsdPtr->hwnd);
	    tsdPtr->hwnd = CreateWindowExW(NULL, className,
		    className, 0, 0, 0, 0, 0, NULL, NULL,
		    TclWinGetTclInstance(), NULL);
	    ResetEvent(tsdPtr->event);
#else
	    pthread_cond_destroy(&tsdPtr->waitCV);
	    pthread_cond_init(&tsdPtr->waitCV, NULL);
#endif

	    /*
	     * In case, we had multiple threads running before the fork,
	     * make sure, we don't try to reach out to their thread local data.
	     */
	    tsdPtr->nextPtr = tsdPtr->prevPtr = NULL;

	    /*
	     * The list of registered event handlers at fork time is in
	     * tsdPtr->firstFileHandlerPtr;
	     */
	}
    }

    Tcl_InitNotifier();
}








#endif /* HAVE_PTHREAD_ATFORK */






























#endif /* TCL_THREADS */




















































































































































#endif /* !HAVE_COREFOUNDATION */

/*
 * Local Variables:
 * mode: c
 * c-basic-offset: 4
 * fill-column: 78
 * End:
 */