/***********************************************************
 *      Copyright (C) 1997, Be Inc.  Copyright (C) 1999, Jake Hamby.
 *
 * This program is freely distributable without licensing fees
 * and is provided without guarantee or warrantee expressed or
 * implied. This program is -not- in the public domain.
 *
 *  FILE:       glutBlocker.cpp
 *
 *      DESCRIPTION:    helper class for GLUT event loop.
 *              if a window receives an event, wake up the event loop.
 ***********************************************************/

/***********************************************************
 *      Headers
 ***********************************************************/
#include "glutBlocker.h"

/***********************************************************
 *      Global variable
 ***********************************************************/
GlutBlocker gBlock;

/***********************************************************
 *      Member functions
 ***********************************************************/
GlutBlocker::GlutBlocker() {
        gSem = create_sem(1, "gSem");
        eSem = create_sem(0, "eSem");
        events = false;
        sleeping = false;
}

GlutBlocker::~GlutBlocker() {
        delete_sem(eSem);
        delete_sem(gSem);
}

void GlutBlocker::WaitEvent() {
        acquire_sem(gSem);
        if(!events) {                   // wait for new event
                sleeping = true;
                release_sem(gSem);
                acquire_sem(eSem);      // next event will release eSem
        } else {
                release_sem(gSem);
        }
}

void GlutBlocker::WaitEvent(bigtime_t usecs) {
        acquire_sem(gSem);
        if(!events) {                   // wait for new event
                sleeping = true;
                release_sem(gSem);
                acquire_sem_etc(eSem, 1, B_TIMEOUT, usecs);     // wait for next event or timeout
        } else {
                release_sem(gSem);
        }
}

void GlutBlocker::NewEvent() {
        acquire_sem(gSem);
        events = true;          // next call to WaitEvent returns immediately
        if(sleeping) {
                sleeping = false;
                release_sem(eSem);      // if event loop is blocking, wake it up
        }
        release_sem(gSem);
}