archie/tcl7.6/win/tclWinNotify.c
2024-05-27 16:40:40 +02:00

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/*
* tclWinNotify.c --
*
* This file contains Windows-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) 1995-1996 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: @(#) tclWinNotify.c 1.11 96/10/03 14:57:16
*/
#include "tclInt.h"
#include "tclPort.h"
#include <winsock.h>
/*
* The following variable is a backdoor for use by Tk. It is set when
* Tk needs to process events on the Tcl event queue without reentering
* the system event loop. Tk uses it to flush the Tcl event queue.
*/
static int ignoreEvents = 0;
/*
*----------------------------------------------------------------------
*
* TclWinFlushEvents --
*
* This function is a special purpose hack to allow Tk to
* process queued Window events during a recursive event loop
* without looking for new events on the system event queue.
*
* Results:
* None.
*
* Side effects:
* Services any pending Tcl events and calls idle handlers.
*
*----------------------------------------------------------------------
*/
void
TclWinFlushEvents()
{
ignoreEvents = 1;
while (Tcl_DoOneEvent(TCL_DONT_WAIT|TCL_WINDOW_EVENTS|TCL_IDLE_EVENTS)) {
}
ignoreEvents = 0;
}
/*
*----------------------------------------------------------------------
*
* 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; /* Opaque identifier for a stream. */
int mask; /* OR'ed combination of TCL_READABLE,
* TCL_WRITABLE, and TCL_EXCEPTION:
* indicates conditions to wait for
* in select. */
{
int type;
(void) Tcl_GetFileInfo(file, &type);
if (type == TCL_WIN_SOCKET) {
TclWinWatchSocket(file, mask);
} else if (type == TCL_WIN_FILE) {
Tcl_Time timeout = { 0, 0 };
/*
* Files are always ready under Windows, so we just set a
* 0 timeout.
*/
Tcl_SetMaxBlockTime(&timeout);
} else if (type == TCL_WIN_PIPE) {
/*
* We don't support waiting on pipes yet.
*/
}
}
/*
*----------------------------------------------------------------------
*
* 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; /* File handle for a stream. */
int mask; /* OR'ed combination of TCL_READABLE,
* TCL_WRITABLE, and TCL_EXCEPTION:
* indicates conditions caller cares about. */
{
int type;
(void) Tcl_GetFileInfo(file, &type);
if (type == TCL_WIN_SOCKET) {
return TclWinSocketReady(file, mask);
} else if (type == TCL_WIN_FILE) {
/*
* Under Windows, files are always ready, so we just return the
* mask that was passed in.
*/
return mask;
}
return 0;
}
/*
*----------------------------------------------------------------------
*
* 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. */
{
MSG msg;
int foundEvent = 1;
/*
* If we are ignoring events from the system, just return immediately.
*/
if (ignoreEvents) {
return TCL_OK;
}
/*
* Set up the asynchronous select handlers for any sockets we
* are watching.
*/
TclWinNotifySocket();
/*
* Look for an event, setting a timer so we don't block forever.
*/
if (timePtr != NULL) {
UINT ms;
ms = timePtr->sec * 1000;
ms += timePtr->usec / 1000;
if (ms > 0) {
UINT timerHandle = SetTimer(NULL, 0, ms, NULL);
GetMessage(&msg, NULL, 0, 0);
KillTimer(NULL, timerHandle);
} else {
/*
* If the timeout is too small, we just poll.
*/
foundEvent = PeekMessage(&msg, NULL, 0, 0, PM_REMOVE);
}
} else {
GetMessage(&msg, NULL, 0, 0);
}
/*
* Dispatch the message, if we found one. If we are exiting, be
* sure to inform Tcl so we can clean up properly.
*/
if (foundEvent) {
if (msg.message == WM_QUIT) {
Tcl_Exit(0);
}
TranslateMessage(&msg);
DispatchMessage(&msg);
}
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. */
{
Sleep(ms);
}