#define LAZY_THREAD_CREATE 1
#define AT_FORK_INIT_VALUE 0
#define DEACTIVATE_ATFORK_MUTEX 0
/*
 * tclUnixNotify.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
 * file.
 */

typedef struct FileHandler {

				 * fields. */
#ifdef __CYGWIN__
    void *event;     /* Any other thread alerts a notifier
	 * that an event is ready to be processed
	 * by sending this event. */
    void *hwnd;			/* Messaging window. */
#else /* !__CYGWIN__ */
    Tcl_Condition waitCV;	/* Any other thread alerts a notifier that an
				 * event is ready to be processed by signaling
				 * this condition variable. */

#endif /* __CYGWIN__ */
    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.
 */

static int notifierCount = 0;

/*
 * The following static stores the process ID of the initialized notifier
 * thread. If it changes, we have passed a fork and we should start a new
 * notifier thread.
 *
 * You must hold the notifierMutex lock before accessing this variable.
 */
static pid_t processIDInitialized = 0;

/*
 * The following variable points to the head of a doubly-linked list of
 * ThreadSpecificData structures for all threads that are currently waiting on
 * an event.
 *
 * You must hold the notifierMutex lock before accessing this list.
 */

static int triggerPipe = -1;

/*
 * The notifierMutex locks access to all of the global notifier state.
 */

TCL_DECLARE_MUTEX(notifierMutex)

#if LAZY_THREAD_CREATE == 1
TCL_DECLARE_MUTEX(notifierInitMutex)

/*
 * The following static indicates if the notifier thread is running.
 *
 * You must hold the notifierInitLock before accessing this variable.
 */

static int notifierThreadRunning = 0;
#endif

/*
 * The notifier thread signals the notifierCV when it has finished
 * initializing the triggerPipe and right before the notifier thread
 * terminates.
 */

static Tcl_Condition notifierCV;

/*
 * The pollState bits
 *	POLL_WANT is set by each thread before it waits on its condition
 *		variable. It is checked by the notifier before it does select.
 *	POLL_DONE is set by the notifier if it goes into select after seeing
 *		POLL_WANT. The idea is to ensure it tries a select with the

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

static DWORD __stdcall	NotifierProc(void *hwnd, unsigned int message,
			    void *wParam, void *lParam);
#endif /* TCL_THREADS && __CYGWIN__ */

#if LAZY_THREAD_CREATE == 1
















static void
StartNotifierThread(void)
{
    fprintf(stderr, "=== StartNotifierThread()\n");
    Tcl_MutexLock(&notifierInitMutex);
    TclpMasterLock();
    TclpMutexLock();
    fprintf(stderr, "=== StartNotifierThread() locked notifierThreadRunning %d notifierCount %d\n", notifierThreadRunning, notifierCount);
    if (!notifierCount) {
	Tcl_Panic("StartNotifierThread: notifier not initialized");
    }

    if (!notifierThreadRunning) {
         fprintf(stderr, "=== StartNotifierThread() really start\n");
	 if (TclpThreadCreate(&notifierThread, NotifierThreadProc, NULL,
	     TCL_THREAD_STACK_DEFAULT, TCL_THREAD_JOINABLE) != TCL_OK) {
	        Tcl_Panic("Tcl_InitNotifier: unable to start notifier thread");
	 }
	 processIDInitialized = getpid();










	 notifierThreadRunning = 1;
    }
    TclpMutexUnlock();
    TclpMasterUnlock();
    Tcl_MutexUnlock(&notifierInitMutex);
}
#endif

/*
 *----------------------------------------------------------------------
 *
 * 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(void)
{
    //fprintf(stderr, "==== Tcl_InitNotifier atForkInit %d notifierCount %d\n", atForkInit, notifierCount);
    if (tclNotifierHooks.initNotifierProc) {
	return tclNotifierHooks.initNotifierProc();
    } else {
	ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); 
#ifdef TCL_THREADS
	tsdPtr->eventReady = 0;


	/*
	 * Start the Notifier thread if necessary.
	 */






	Tcl_MutexLock(&notifierMutex);

#if defined(HAVE_PTHREAD_ATFORK) && !defined(__APPLE__) && !defined(__hpux)
	/*
	 * Install pthread_atfork handlers to reinitialize the notifier in the
	 * child of a fork.
	 */
	if (!atForkInit) {
	    int result = pthread_atfork(AtForkPrepare, AtForkParent, AtForkChild);
            fprintf(stderr, "==== calling pthread_atfork()\n");

	    if (result) {
		Tcl_Panic("Tcl_InitNotifier: pthread_atfork failed");
	    }
	    atForkInit = 1;
	}
#endif /* HAVE_PTHREAD_ATFORK */
	/*
	 * Check if my process id changed, e.g. I was forked
	 * In this case, restart the notifier thread and close the
	 * pipe to the original notifier thread
	 */
#if LAZY_THREAD_CREATE == 0
	if (notifierCount > 0 && processIDInitialized != getpid()) {
            // fprintf(stderr, "==== reset notifierCount for %d\n", getpid());
	    Tcl_ConditionFinalize(&notifierCV);
	    notifierCount = 0;
	    processIDInitialized = 0;
	    close(triggerPipe);
	    triggerPipe = -1;
	}
#endif
	if (notifierCount == 0) {
#if LAZY_THREAD_CREATE == 0
	    if (TclpThreadCreate(&notifierThread, NotifierThreadProc, NULL,
		    TCL_THREAD_STACK_DEFAULT, TCL_THREAD_JOINABLE) != TCL_OK) {
		Tcl_Panic("Tcl_InitNotifier: unable to start notifier thread");
	    }
	    processIDInitialized = getpid();
#endif
	}
	notifierCount++;

#if LAZY_THREAD_CREATE == 0
	/*
	 * Wait for the notifier pipe to be created.
	 */

	while (triggerPipe < 0) {
	    Tcl_ConditionWait(&notifierCV, &notifierMutex, NULL);
	}
#endif

	Tcl_MutexUnlock(&notifierMutex);
#endif /* TCL_THREADS */
	return tsdPtr;
    }
}

/*
 *----------------------------------------------------------------------

    if (tclNotifierHooks.finalizeNotifierProc) {
	tclNotifierHooks.finalizeNotifierProc(clientData);
	return;
    } else {
#ifdef TCL_THREADS
	ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);









	Tcl_MutexLock(&notifierMutex);
	notifierCount--;
    //fprintf(stderr, "==== Tcl_Tcl_FinalizeNotifier (after decr) atForkInit %d notifierCount %d\n", atForkInit, notifierCount);

	/*
	 * If this is the last thread to use the notifier, close the notifier
	 * pipe and wait for the background thread to terminate.
	 */

	if (notifierCount == 0) {
#if LAZY_THREAD_CREATE == 1
	    if (triggerPipe != -1) {
	        if (write(triggerPipe, "q", 1) != 1) {
		    Tcl_Panic("Tcl_FinalizeNotifier: %s",
			    "unable to write q to triggerPipe");
	        }
    	        close(triggerPipe);
                triggerPipe = -1;


	        if (notifierThreadRunning) {
	            int result = Tcl_JoinThread(notifierThread, NULL);

		    if (result) {
		        Tcl_Panic("Tcl_FinalizeNotifier: unable to join notifier "
		    	    "thread");
	    	    }
		    notifierThreadRunning = 0;
	        }
            }
#else
	    int result;

# if AT_FORK_INIT_VALUE == 1
	    if (triggerPipe != -1) {
	        if (write(triggerPipe, "q", 1) != 1) {
		    Tcl_Panic("Tcl_FinalizeNotifier: %s",
			    "unable to write q to triggerPipe");
	        }
    	        close(triggerPipe);
                triggerPipe = -1;
            }
# else

	    if (triggerPipe < 0) {
		Tcl_Panic("Tcl_FinalizeNotifier: %s",
			"notifier pipe not initialized");
	    }

	    /*
	     * Send "q" message to the notifier thread so that it will
	     * terminate. The notifier will return from its call to select()
	     * and notice that a "q" message has arrived, it will then close
	     * its side of the pipe and terminate its thread. Note the we can
	     * not just close the pipe and check for EOF in the notifier thread
	     * because if a background child process was created with exec,
	     * select() would not register the EOF on the pipe until the child
	     * processes had terminated. [Bug: 4139] [Bug: 1222872]
	     */

	    if (write(triggerPipe, "q", 1) != 1) {
		Tcl_Panic("Tcl_FinalizeNotifier: %s",
			"unable to write q to triggerPipe");
	    }
	    close(triggerPipe);
	    while(triggerPipe >= 0) {
		Tcl_ConditionWait(&notifierCV, &notifierMutex, NULL);
	    }

	    result = Tcl_JoinThread(notifierThread, NULL);
	    if (result) {
		Tcl_Panic("Tcl_FinalizeNotifier: %s",
			"unable to join notifier thread");
	    }
# endif
#endif
	}

	/*
	 * Clean up any synchronization objects in the thread local storage.
	 */

#ifdef __CYGWIN__
	CloseHandle(tsdPtr->event);
#else /* __CYGWIN__ */
	Tcl_ConditionFinalize(&(tsdPtr->waitCV));
#endif /* __CYGWIN__ */

	Tcl_MutexUnlock(&notifierMutex);

#endif /* TCL_THREADS */
    }
}

/*
 *----------------------------------------------------------------------
 *

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

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

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

	Tcl_MutexUnlock(&notifierMutex);
#endif /* TCL_THREADS */
    }
}

/*
 *----------------------------------------------------------------------
 *

    int mode)			/* Either TCL_SERVICE_ALL, or
				 * TCL_SERVICE_NONE. */
{
    fprintf(stderr, "==== Tcl_ServiceModeHook mode %d\n", mode);
    if (tclNotifierHooks.serviceModeHookProc) {
	tclNotifierHooks.serviceModeHookProc(mode);
	return;
    } else {
#if LAZY_THREAD_CREATE == 1
       if (mode == TCL_SERVICE_ALL) {

           StartNotifierThread();
       }
#else
	/* Does nothing in this implementation. */
#endif
    }
}

/*
 *----------------------------------------------------------------------
 *

    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) {

	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) {

     * Search through the file handlers to find the one whose handle matches
     * the event. We do this rather than keeping a pointer to the file handler
     * directly in the event, so that the handler can be deleted while the
     * event is queued without leaving a dangling pointer.
     */

    tsdPtr = TCL_TSD_INIT(&dataKey);








    for (filePtr = tsdPtr->firstFileHandlerPtr; filePtr != NULL;
	    filePtr = filePtr->nextPtr) {
	if (filePtr->fd != fileEvPtr->fd) {
	    continue;
	}

	/*
	 * The code is tricky for two reasons:
	 * 1. The file handler's desired events could have changed since the

	 */

	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) {

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

#ifdef TCL_THREADS
	/*
	 * Place this thread on the list of interested threads, signal the

	 * notifier thread, and wait for a response or a timeout.
	 */
#if LAZY_THREAD_CREATE == 1
	StartNotifierThread();
#endif

#ifdef __CYGWIN__
	if (!tsdPtr->hwnd) {
	    WNDCLASS class;

	    class.style = 0;
	    class.cbClsExtra = 0;

		    class.lpszClassName, 0, 0, 0, 0, 0, NULL, NULL,
		    TclWinGetTclInstance(), NULL);
	    tsdPtr->event = CreateEventW(NULL, 1 /* manual */,
		    0 /* !signaled */, NULL);
	}
#endif /* __CYGWIN */

	Tcl_MutexLock(&notifierMutex);

	if (timePtr != NULL && timePtr->sec == 0 && (timePtr->usec == 0
#if defined(__APPLE__) && defined(__LP64__)
		/*
		 * On 64-bit Darwin, pthread_cond_timedwait() appears to have
		 * a bug that causes it to wait forever when passed an
		 * absolute time which has already been exceeded by the system

		DWORD timeout;

		if (timePtr) {
		    timeout = timePtr->sec * 1000 + timePtr->usec / 1000;
		} else {
		    timeout = 0xFFFFFFFF;
		}
		Tcl_MutexUnlock(&notifierMutex);
		MsgWaitForMultipleObjects(1, &tsdPtr->event, 0, timeout, 1279);
		Tcl_MutexLock(&notifierMutex);
	    }
#else
	    Tcl_ConditionWait(&tsdPtr->waitCV, &notifierMutex, timePtr);
#endif /* __CYGWIN__ */
	}
	tsdPtr->eventReady = 0;

#ifdef __CYGWIN__
	while (PeekMessageW(&msg, NULL, 0, 0, 0)) {
	    /*

		fileEvPtr->header.proc = FileHandlerEventProc;
		fileEvPtr->fd = filePtr->fd;
		Tcl_QueueEvent((Tcl_Event *) fileEvPtr, TCL_QUEUE_TAIL);
	    }
	    filePtr->readyMask = mask;
	}
#ifdef TCL_THREADS
	Tcl_MutexUnlock(&notifierMutex);
#endif /* TCL_THREADS */
	return 0;
    }
}

#ifdef TCL_THREADS
/*

		"could not make receive pipe close-on-exec");
    }
    if (fcntl(fds[1], F_SETFD, FD_CLOEXEC) < 0) {
	Tcl_Panic("NotifierThreadProc: %s",
		"could not make trigger pipe close-on-exec");
    }

// fprintf(stderr, "=== Starting Notifier Thread\n");
    /*
     * Install the write end of the pipe into the global variable.
     */

    Tcl_MutexLock(&notifierMutex);
    triggerPipe = fds[1];

    /*
     * Signal any threads that are waiting.
     */



    Tcl_ConditionNotify(&notifierCV);
    Tcl_MutexUnlock(&notifierMutex);

    /*
     * Look for file events and report them to interested threads.
     */

    while (1) {
	FD_ZERO(&readableMask);
	FD_ZERO(&writableMask);
	FD_ZERO(&exceptionMask);

	/*
	 * Compute the logical OR of the select masks from all the waiting
	 * notifiers.
	 */

	Tcl_MutexLock(&notifierMutex);

	timePtr = NULL;
	for (tsdPtr = waitingListPtr; tsdPtr; tsdPtr = tsdPtr->nextPtr) {
	    for (i = tsdPtr->numFdBits-1; i >= 0; --i) {
		if (FD_ISSET(i, &tsdPtr->checkMasks.readable)) {
		    FD_SET(i, &readableMask);
		}
		if (FD_ISSET(i, &tsdPtr->checkMasks.writable)) {

		 * bits that were present when the thread tried to poll.
		 */

		tsdPtr->pollState |= POLL_DONE;
		timePtr = &poll;
	    }
	}
	Tcl_MutexUnlock(&notifierMutex);

	/*
	 * Set up the select mask to include the receive pipe.
	 */

	if (receivePipe >= numFdBits) {
	    numFdBits = receivePipe + 1;
	}
	FD_SET(receivePipe, &readableMask);

	if (select(numFdBits, &readableMask, &writableMask, &exceptionMask,
		timePtr) == -1) {
	    /*
	     * Try again immediately on an error.
	     */

	    continue;
	}

	/*
	 * Alert any threads that are waiting on a ready file descriptor.
	 */

	Tcl_MutexLock(&notifierMutex);

	for (tsdPtr = waitingListPtr; tsdPtr; tsdPtr = tsdPtr->nextPtr) {
	    found = 0;

	    for (i = tsdPtr->numFdBits-1; i >= 0; --i) {
		if (FD_ISSET(i, &tsdPtr->checkMasks.readable)
			&& FD_ISSET(i, &readableMask)) {
		    FD_SET(i, &tsdPtr->readyMasks.readable);

		    tsdPtr->nextPtr = tsdPtr->prevPtr = NULL;
		    tsdPtr->onList = 0;
		    tsdPtr->pollState = 0;
		}
#ifdef __CYGWIN__
		PostMessageW(tsdPtr->hwnd, 1024, 0, 0);
#else
		Tcl_ConditionNotify(&tsdPtr->waitCV);
#endif /* __CYGWIN__ */
	    }
	}
	Tcl_MutexUnlock(&notifierMutex);

	/*
	 * Consume the next byte from the notifier pipe if the pipe was
	 * readable. Note that there may be multiple bytes pending, but to
	 * avoid a race condition we only read one at a time.
	 */

	if (FD_ISSET(receivePipe, &readableMask)) {
	    i = read(receivePipe, buf, 1);

	    if ((i == 0) || ((i == 1) && (buf[0] == 'q'))) {
		/*
		 * Someone closed the write end of the pipe or sent us a Quit
		 * message [Bug: 4139] and then closed the write end of the

    /*
     * Clean up the read end of the pipe and signal any threads waiting on
     * termination of the notifier thread.
     */
fprintf(stderr, "=== Stopping Notifier Thread\n");

    close(receivePipe);

    Tcl_MutexLock(&notifierMutex);
    triggerPipe = -1;
    Tcl_ConditionNotify(&notifierCV);
    Tcl_MutexUnlock(&notifierMutex);

    TclpThreadExit(0);
}

#if defined(HAVE_PTHREAD_ATFORK) && !defined(__APPLE__) && !defined(__hpux)
/*
 *----------------------------------------------------------------------

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

static void
AtForkPrepare(void)
{
#if DEACTIVATE_ATFORK_MUTEX == 0
    Tcl_MutexLock(&notifierMutex);
    TclpMasterLock();
    TclpMutexLock();
#endif
}

/*
 *----------------------------------------------------------------------
 *
 * AtForkParent --

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

static void
AtForkParent(void)
{
#if DEACTIVATE_ATFORK_MUTEX == 0
    TclpMutexUnlock();
    TclpMasterUnlock();
    Tcl_MutexUnlock(&notifierMutex);
#endif
    //fprintf(stderr, "====  atParent %d notifierCount %d atForkInit %d\n", atForkInit, notifierCount, atForkInit);
}


/*
 *----------------------------------------------------------------------
 *
 * AtForkChild --
 *
 *	Unlock and reinstall the notifier in the child after a fork.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static void
AtForkChild(void)
{



#if DEACTIVATE_ATFORK_MUTEX == 0
    TclpMutexUnlock();
    TclpMasterUnlock();


    TclMutexUnlockAndFinalize(&notifierMutex);
#endif


#if LAZY_THREAD_CREATE == 1
    //Tcl_MutexLock(&notifierInitMutex);

    notifierThreadRunning = 0;




    if (notifierCount > 0) {

         Tcl_ConditionFinalize(&notifierCV);
         notifierCount = 0;





         processIDInitialized = 0;
         close(triggerPipe);
         triggerPipe = -1;






    }
    //Tcl_MutexUnlock(&notifierInitMutex);








#endif









    // fprintf(stderr, "==== AtForkChild() notifierCount %d notifierThreadRunning %d atForkInit %d\n",notifierCount,notifierThreadRunning, atForkInit);
    Tcl_InitNotifier();
}
#endif /* HAVE_PTHREAD_ATFORK */

#endif /* TCL_THREADS */

#endif /* !HAVE_COREFOUNDATION */