Initial import of the CDE 2.1.30 sources from the Open Group.

cde/programs/dtdocbook/tcl/tclUnixNotfy.c

@@ -0,0 +1,324 @@
+/* $TOG: tclUnixNotfy.c /main/3 1998/04/06 13:37:34 mgreess $ */
+/* 
+ * tclUnixNotify.c --
+ *
+ *	This file contains Unix-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 Sun Microsystems, Inc.
+ *
+ * See the file "license.terms" for information on usage and redistribution
+ * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
+ *
+ * SCCS: @(#) tclUnixNotfy.c 1.30 96/03/22 12:45:31
+ */
+
+#include "tclInt.h"
+#include "tclPort.h"
+#include <signal.h> 
+#include <sys/time.h> 
+
+/*
+ * The information below is used to provide read, write, and
+ * exception masks to select during calls to Tcl_DoOneEvent.
+ */
+
+static fd_mask checkMasks[3*MASK_SIZE];
+				/* This array is used to build up the masks
+				 * to be used in the next call to select.
+				 * Bits are set in response to calls to
+				 * Tcl_WatchFile. */
+static fd_mask readyMasks[3*MASK_SIZE];
+				/* This array reflects the readable/writable
+				 * conditions that were found to exist by the
+				 * last call to select. */
+static int numFdBits;		/* Number of valid bits in checkMasks
+				 * (one more than highest fd for which
+				 * Tcl_WatchFile has been called). */
+
+/*
+ * Static routines in this file:
+ */
+
+static int	MaskEmpty _ANSI_ARGS_((long *maskPtr));
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_WatchFile --
+ *
+ *	Arrange for Tcl_DoOneEvent to include this file in the masks
+ *	for the next call to select.  This procedure is invoked by
+ *	event sources, which are in turn invoked by Tcl_DoOneEvent
+ *	before it invokes select.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	
+ *	The notifier will generate a file event when the I/O channel
+ *	given by fd next becomes ready in the way indicated by mask.
+ *	If fd is already registered then the old mask will be replaced
+ *	with the new one.  Once the event is sent, the notifier will
+ *	not send any more events about the fd until the next call to
+ *	Tcl_NotifyFile. 
+ *
+ *----------------------------------------------------------------------
+ */
+
+void
+Tcl_WatchFile(file, mask)
+    Tcl_File file;	/* Generic file handle for a stream. */
+    int mask;			/* OR'ed combination of TCL_READABLE,
+				 * TCL_WRITABLE, and TCL_EXCEPTION:
+				 * indicates conditions to wait for
+				 * in select. */
+{
+    int fd, type, index;
+    fd_mask bit;
+
+    fd = (int) Tcl_GetFileInfo(file, &type);
+
+    if (type != TCL_UNIX_FD) {
+	panic("Tcl_WatchFile: unexpected file type");
+    }
+
+    if (fd >= FD_SETSIZE) {
+	panic("Tcl_WatchFile can't handle file id %d", fd);
+    }
+
+    index = fd/(NBBY*sizeof(fd_mask));
+    bit = 1 << (fd%(NBBY*sizeof(fd_mask)));
+    if (mask & TCL_READABLE) {
+	checkMasks[index] |= bit;
+    }
+    if (mask & TCL_WRITABLE) {
+	(checkMasks+MASK_SIZE)[index] |= bit;
+    }
+    if (mask & TCL_EXCEPTION) {
+	(checkMasks+2*(MASK_SIZE))[index] |= bit;
+    }
+    if (numFdBits <= fd) {
+	numFdBits = fd+1;
+    }
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_FileReady --
+ *
+ *	Indicates what conditions (readable, writable, etc.) were
+ *	present on a file the last time the notifier invoked select.
+ *	This procedure is typically invoked by event sources to see
+ *	if they should queue events.
+ *
+ * Results:
+ *	The return value is 0 if none of the conditions specified by mask
+ *	was true for fd the last time the system checked.  If any of the
+ *	conditions were true, then the return value is a mask of those
+ *	that were true.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+Tcl_FileReady(file, mask)
+    Tcl_File file;	/* Generic file handle for a stream. */
+    int mask;			/* OR'ed combination of TCL_READABLE,
+				 * TCL_WRITABLE, and TCL_EXCEPTION:
+				 * indicates conditions caller cares about. */
+{
+    int index, result, type, fd;
+    fd_mask bit;
+
+    fd = (int) Tcl_GetFileInfo(file, &type);
+    if (type != TCL_UNIX_FD) {
+	panic("Tcl_FileReady: unexpected file type");
+    }
+
+    index = fd/(NBBY*sizeof(fd_mask));
+    bit = 1 << (fd%(NBBY*sizeof(fd_mask)));
+    result = 0;
+    if ((mask & TCL_READABLE) && (readyMasks[index] & bit)) {
+	result |= TCL_READABLE;
+    }
+    if ((mask & TCL_WRITABLE) && ((readyMasks+MASK_SIZE)[index] & bit)) {
+	result |= TCL_WRITABLE;
+    }
+    if ((mask & TCL_EXCEPTION) && ((readyMasks+(2*MASK_SIZE))[index] & bit)) {
+	result |= TCL_EXCEPTION;
+    }
+    return result;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * MaskEmpty --
+ *
+ *	Returns nonzero if mask is empty (has no bits set).
+ *
+ * Results:
+ *	Nonzero if the mask is empty, zero otherwise.
+ *
+ * Side effects:
+ *	None
+ *
+ *----------------------------------------------------------------------
+ */
+
+static int
+MaskEmpty(maskPtr)
+    long *maskPtr;
+{
+    long *runPtr, *tailPtr;
+    int found, sz;
+
+    sz = 3 * ((MASK_SIZE) / sizeof(long)) * sizeof(fd_mask);
+    for (runPtr = maskPtr, tailPtr = maskPtr + sz, found = 0;
+             runPtr < tailPtr;
+             runPtr++) {
+        if (*runPtr != 0) {
+            found = 1;
+            break;
+        }
+    }
+    return !found;    
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * Tcl_WaitForEvent --
+ *
+ *	This procedure does the lowest level wait for events in a
+ *	platform-specific manner.  It uses information provided by
+ *	previous calls to Tcl_WatchFile, plus the timePtr argument,
+ *	to determine what to wait for and how long to wait.
+ *
+ * Results:
+ *	The return value is normally TCL_OK.  However, if there are
+ *	no events to wait for (e.g. no files and no timers) so that
+ *	the procedure would block forever, then it returns TCL_ERROR.
+ *
+ * Side effects:
+ *	May put the process to sleep for a while, depending on timePtr.
+ *	When this procedure returns, an event of interest to the application
+ *	has probably, but not necessarily, occurred.
+ *
+ *----------------------------------------------------------------------
+ */
+
+int
+Tcl_WaitForEvent(timePtr)
+    Tcl_Time *timePtr;		/* Specifies the maximum amount of time
+				 * that this procedure should block before
+				 * returning.  The time is given as an
+				 * interval, not an absolute wakeup time.
+				 * NULL means block forever. */
+{
+    struct timeval timeout, *timeoutPtr;
+    int numFound;
+
+    memcpy((VOID *) readyMasks, (VOID *) checkMasks,
+	    3*MASK_SIZE*sizeof(fd_mask));
+    if (timePtr == NULL) {
+	if ((numFdBits == 0) || (MaskEmpty((long *) readyMasks))) {
+	    return TCL_ERROR;
+	}
+	timeoutPtr = NULL;
+    } else {
+	timeoutPtr = &timeout;
+	timeout.tv_sec = timePtr->sec;
+	timeout.tv_usec = timePtr->usec;
+    }
+    numFound = select(numFdBits, (SELECT_MASK *) &readyMasks[0],
+	    (SELECT_MASK *) &readyMasks[MASK_SIZE],
+	    (SELECT_MASK *) &readyMasks[2*MASK_SIZE], timeoutPtr);
+
+    /*
+     * Some systems don't clear the masks after an error, so
+     * we have to do it here.
+     */
+
+    if (numFound == -1) {
+	memset((VOID *) readyMasks, 0, 3*MASK_SIZE*sizeof(fd_mask));
+    }
+
+    /*
+     * Reset the check masks in preparation for the next call to
+     * select.
+     */
+
+    numFdBits = 0;
+    memset((VOID *) checkMasks, 0, 3*MASK_SIZE*sizeof(fd_mask));
+    return TCL_OK;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * 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. */
+{
+    static struct timeval delay;
+    Tcl_Time before, after;
+
+    /*
+     * The only trick here is that select appears to return early
+     * under some conditions, so we have to check to make sure that
+     * the right amount of time really has elapsed.  If it's too
+     * early, go back to sleep again.
+     */
+
+    TclGetTime(&before);
+    after = before;
+    after.sec += ms/1000;
+    after.usec += (ms%1000)*1000;
+    if (after.usec > 1000000) {
+	after.usec -= 1000000;
+	after.sec += 1;
+    }
+    while (1) {
+	delay.tv_sec = after.sec - before.sec;
+	delay.tv_usec = after.usec - before.usec;
+	if (delay.tv_usec < 0) {
+	    delay.tv_usec += 1000000;
+	    delay.tv_sec -= 1;
+	}
+
+	/*
+	 * Special note:  must convert delay.tv_sec to int before comparing
+	 * to zero, since delay.tv_usec is unsigned on some platforms.
+	 */
+
+	if ((((int) delay.tv_sec) < 0)
+		|| ((delay.tv_usec == 0) && (delay.tv_sec == 0))) {
+	    break;
+	}
+	(void) select(0, (SELECT_MASK *) 0, (SELECT_MASK *) 0,
+		(SELECT_MASK *) 0, &delay);
+	TclGetTime(&before);
+    }
+}
+