/*
 * 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.
 *
 * RCS: @(#) $Id: tclUnixNotfy.c,v 1.28 2005/07/24 22:56:44 dkf Exp $
 */

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

/*
 * This code does deep stub magic to allow replacement of the notifier at
 * runtime.
 */

extern TclStubs tclStubs;

 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

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

#ifdef TCL_THREADS
    tsdPtr->eventReady = 0;

    /*

 *	May terminate the background notifier thread if this is the last
 *	notifier instance.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_FinalizeNotifier(clientData)
    ClientData clientData;		/* Not used. */
{
#ifdef TCL_THREADS
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);

    Tcl_MutexLock(&notifierMutex);
    notifierCount--;

 * Side effects:
 *	Signals the notifier condition variable for the specified notifier.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_AlertNotifier(clientData)
    ClientData clientData;
{
#ifdef TCL_THREADS
    ThreadSpecificData *tsdPtr = (ThreadSpecificData *) clientData;
    Tcl_MutexLock(&notifierMutex);
    tsdPtr->eventReady = 1;
    Tcl_ConditionNotify(&tsdPtr->waitCV);
    Tcl_MutexUnlock(&notifierMutex);

 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_SetTimer(timePtr)
    Tcl_Time *timePtr;		/* Timeout value, may be NULL. */
{
    /*
     * 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.
     */

 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_ServiceModeHook(mode)
    int mode;			/* Either TCL_SERVICE_ALL, or
				 * TCL_SERVICE_NONE. */
{
}

/*
 *----------------------------------------------------------------------
 *

 * Side effects:
 *	Creates a new file handler structure.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_CreateFileHandler(fd, mask, proc, clientData)
    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. */
{
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
    FileHandler *filePtr;

    if (tclStubs.tcl_CreateFileHandler != tclOriginalNotifier.createFileHandlerProc) {
	tclStubs.tcl_CreateFileHandler(fd, mask, proc, clientData);
	return;

 * Side effects:
 *	If a callback was previously registered on file, remove it.
 *
 *----------------------------------------------------------------------
 */

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

    if (tclStubs.tcl_DeleteFileHandler != tclOriginalNotifier.deleteFileHandlerProc) {

 * Side effects:
 *	Whatever the file handler's callback function does.
 *
 *----------------------------------------------------------------------
 */

static int
FileHandlerEventProc(evPtr, flags)
    Tcl_Event *evPtr;		/* Event to service. */
    int flags;			/* Flags that indicate what events to handle,
				 * such as TCL_FILE_EVENTS. */
{
    int mask;
    FileHandler *filePtr;
    FileHandlerEvent *fileEvPtr = (FileHandlerEvent *) evPtr;
    ThreadSpecificData *tsdPtr;

 * Side effects:
 *	Queues file events that are detected by the select.
 *
 *----------------------------------------------------------------------
 */

int
Tcl_WaitForEvent(timePtr)
    Tcl_Time *timePtr;		/* Maximum block time, or NULL. */
{
    FileHandler *filePtr;
    FileHandlerEvent *fileEvPtr;
    int mask;
    Tcl_Time myTime;
#ifdef TCL_THREADS
    int waitForFiles;

 *	The trigger pipe used to signal the notifier thread is created when
 *	the notifier thread first starts.
 *
 *----------------------------------------------------------------------
 */

static void
NotifierThreadProc(clientData)
    ClientData clientData;	/* Not used. */
{
    ThreadSpecificData *tsdPtr;
    fd_set readableMask;
    fd_set writableMask;
    fd_set exceptionalMask;
    int fds[2];
    int i, status, numFdBits = 0, receivePipe;