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Diffstat (limited to 'unix/tclXtNotify.c')
| -rw-r--r-- | unix/tclXtNotify.c | 667 |
1 files changed, 667 insertions, 0 deletions
diff --git a/unix/tclXtNotify.c b/unix/tclXtNotify.c new file mode 100644 index 0000000..a5d92d6 --- /dev/null +++ b/unix/tclXtNotify.c @@ -0,0 +1,667 @@ +/* + * tclXtNotify.c -- + * + * This file contains the notifier driver implementation for the Xt + * intrinsics. + * + * Copyright (c) 1997 by Sun Microsystems, Inc. + * + * See the file "license.terms" for information on usage and redistribution of + * this file, and for a DISCLAIMER OF ALL WARRANTIES. + */ + +#ifndef USE_TCL_STUBS +# define USE_TCL_STUBS +#endif +#include <X11/Intrinsic.h> +#include "tclInt.h" + +/* + * This structure is used to keep track of the notifier info for a a + * registered file. + */ + +typedef struct FileHandler { + int fd; + int mask; /* Mask of desired events: TCL_READABLE, + * etc. */ + int readyMask; /* Events that have been seen since the last + * time FileHandlerEventProc was called for + * this file. */ + XtInputId read; /* Xt read callback handle. */ + XtInputId write; /* Xt write callback handle. */ + XtInputId except; /* Xt exception callback handle. */ + Tcl_FileProc *proc; /* Procedure to call, in the style of + * Tcl_CreateFileHandler. */ + ClientData clientData; /* Argument to pass to proc. */ + struct FileHandler *nextPtr;/* Next in list of all files we care about. */ +} FileHandler; + +/* + * The following structure is what is added to the Tcl event queue when file + * handlers are ready to fire. + */ + +typedef struct FileHandlerEvent { + Tcl_Event header; /* Information that is standard for all + * events. */ + int fd; /* File descriptor that is ready. Used to find + * the FileHandler structure for the file + * (can't point directly to the FileHandler + * structure because it could go away while + * the event is queued). */ +} FileHandlerEvent; + +/* + * The following static structure contains the state information for the Xt + * based implementation of the Tcl notifier. + */ + +static struct NotifierState { + XtAppContext appContext; /* The context used by the Xt notifier. Can be + * set with TclSetAppContext. */ + int appContextCreated; /* Was it created by us? */ + XtIntervalId currentTimeout;/* Handle of current timer. */ + FileHandler *firstFileHandlerPtr; + /* Pointer to head of file handler list. */ +} notifier; + +/* + * The following static indicates whether this module has been initialized. + */ + +static int initialized = 0; + +/* + * Static routines defined in this file. + */ + +static int FileHandlerEventProc(Tcl_Event *evPtr, int flags); +static void FileProc(XtPointer clientData, int *source, + XtInputId *id); +static void NotifierExitHandler(ClientData clientData); +static void TimerProc(XtPointer clientData, XtIntervalId *id); +static void CreateFileHandler(int fd, int mask, + Tcl_FileProc *proc, ClientData clientData); +static void DeleteFileHandler(int fd); +static void SetTimer(const Tcl_Time * timePtr); +static int WaitForEvent(const Tcl_Time * timePtr); + +/* + * Functions defined in this file for use by users of the Xt Notifier: + */ + +MODULE_SCOPE void InitNotifier(void); +MODULE_SCOPE XtAppContext TclSetAppContext(XtAppContext ctx); + +/* + *---------------------------------------------------------------------- + * + * TclSetAppContext -- + * + * Set the notifier application context. + * + * Results: + * None. + * + * Side effects: + * Sets the application context used by the notifier. Panics if the + * context is already set when called. + * + *---------------------------------------------------------------------- + */ + +XtAppContext +TclSetAppContext( + XtAppContext appContext) +{ + if (!initialized) { + InitNotifier(); + } + + /* + * If we already have a context we check whether we were asked to set a + * new context. If so, we panic because we try to prevent switching + * contexts by mistake. Otherwise, we return the one we have. + */ + + if (notifier.appContext != NULL) { + if (appContext != NULL) { + /* + * We already have a context. We do not allow switching contexts + * after initialization, so we panic. + */ + + Tcl_Panic("TclSetAppContext: multiple application contexts"); + } + } else { + /* + * If we get here we have not yet gotten a context, so either create + * one or use the one supplied by our caller. + */ + + if (appContext == NULL) { + /* + * We must create a new context and tell our caller what it is, so + * she can use it too. + */ + + notifier.appContext = XtCreateApplicationContext(); + notifier.appContextCreated = 1; + } else { + /* + * Otherwise we remember the context that our caller gave us and + * use it. + */ + + notifier.appContextCreated = 0; + notifier.appContext = appContext; + } + } + + return notifier.appContext; +} + +/* + *---------------------------------------------------------------------- + * + * InitNotifier -- + * + * Initializes the notifier state. + * + * Results: + * None. + * + * Side effects: + * Creates a new exit handler. + * + *---------------------------------------------------------------------- + */ + +void +InitNotifier(void) +{ + Tcl_NotifierProcs np; + + /* + * Only reinitialize if we are not in exit handling. The notifier can get + * reinitialized after its own exit handler has run, because of exit + * handlers for the I/O and timer sub-systems (order dependency). + */ + + if (TclInExit()) { + return; + } + + np.createFileHandlerProc = CreateFileHandler; + np.deleteFileHandlerProc = DeleteFileHandler; + np.setTimerProc = SetTimer; + np.waitForEventProc = WaitForEvent; + np.initNotifierProc = Tcl_InitNotifier; + np.finalizeNotifierProc = Tcl_FinalizeNotifier; + np.alertNotifierProc = Tcl_AlertNotifier; + np.serviceModeHookProc = Tcl_ServiceModeHook; + Tcl_SetNotifier(&np); + + /* + * DO NOT create the application context yet; doing so would prevent + * external applications from setting it for us to their own ones. + */ + + initialized = 1; + memset(&np, 0, sizeof(np)); + Tcl_CreateExitHandler(NotifierExitHandler, NULL); +} + +/* + *---------------------------------------------------------------------- + * + * NotifierExitHandler -- + * + * This function is called to cleanup the notifier state before Tcl is + * unloaded. + * + * Results: + * None. + * + * Side effects: + * Destroys the notifier window. + * + *---------------------------------------------------------------------- + */ + +static void +NotifierExitHandler( + ClientData clientData) /* Not used. */ +{ + if (notifier.currentTimeout != 0) { + XtRemoveTimeOut(notifier.currentTimeout); + } + for (; notifier.firstFileHandlerPtr != NULL; ) { + Tcl_DeleteFileHandler(notifier.firstFileHandlerPtr->fd); + } + if (notifier.appContextCreated) { + XtDestroyApplicationContext(notifier.appContext); + notifier.appContextCreated = 0; + notifier.appContext = NULL; + } + initialized = 0; +} + +/* + *---------------------------------------------------------------------- + * + * SetTimer -- + * + * This procedure sets the current notifier timeout value. + * + * Results: + * None. + * + * Side effects: + * Replaces any previous timer. + * + *---------------------------------------------------------------------- + */ + +static void +SetTimer( + const Tcl_Time *timePtr) /* Timeout value, may be NULL. */ +{ + long timeout; + + if (!initialized) { + InitNotifier(); + } + + TclSetAppContext(NULL); + if (notifier.currentTimeout != 0) { + XtRemoveTimeOut(notifier.currentTimeout); + } + if (timePtr) { + timeout = timePtr->sec * 1000 + timePtr->usec / 1000; + notifier.currentTimeout = XtAppAddTimeOut(notifier.appContext, + (unsigned long) timeout, TimerProc, NULL); + } else { + notifier.currentTimeout = 0; + } +} + +/* + *---------------------------------------------------------------------- + * + * TimerProc -- + * + * This procedure is the XtTimerCallbackProc used to handle timeouts. + * + * Results: + * None. + * + * Side effects: + * Processes all queued events. + * + *---------------------------------------------------------------------- + */ + +static void +TimerProc( + XtPointer clientData, /* Not used. */ + XtIntervalId *id) +{ + if (*id != notifier.currentTimeout) { + return; + } + notifier.currentTimeout = 0; + + Tcl_ServiceAll(); +} + +/* + *---------------------------------------------------------------------- + * + * CreateFileHandler -- + * + * This procedure registers a file handler with the Xt notifier. + * + * Results: + * None. + * + * Side effects: + * Creates a new file handler structure and registers one or more input + * procedures with Xt. + * + *---------------------------------------------------------------------- + */ + +static void +CreateFileHandler( + 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, /* Procedure to call for each selected + * event. */ + ClientData clientData) /* Arbitrary data to pass to proc. */ +{ + FileHandler *filePtr; + + if (!initialized) { + InitNotifier(); + } + + TclSetAppContext(NULL); + + for (filePtr = notifier.firstFileHandlerPtr; filePtr != NULL; + filePtr = filePtr->nextPtr) { + if (filePtr->fd == fd) { + break; + } + } + if (filePtr == NULL) { + filePtr = ckalloc(sizeof(FileHandler)); + filePtr->fd = fd; + filePtr->read = 0; + filePtr->write = 0; + filePtr->except = 0; + filePtr->readyMask = 0; + filePtr->mask = 0; + filePtr->nextPtr = notifier.firstFileHandlerPtr; + notifier.firstFileHandlerPtr = filePtr; + } + filePtr->proc = proc; + filePtr->clientData = clientData; + + /* + * Register the file with the Xt notifier, if it hasn't been done yet. + */ + + if (mask & TCL_READABLE) { + if (!(filePtr->mask & TCL_READABLE)) { + filePtr->read = XtAppAddInput(notifier.appContext, fd, + INT2PTR(XtInputReadMask), FileProc, filePtr); + } + } else { + if (filePtr->mask & TCL_READABLE) { + XtRemoveInput(filePtr->read); + } + } + if (mask & TCL_WRITABLE) { + if (!(filePtr->mask & TCL_WRITABLE)) { + filePtr->write = XtAppAddInput(notifier.appContext, fd, + INT2PTR(XtInputWriteMask), FileProc, filePtr); + } + } else { + if (filePtr->mask & TCL_WRITABLE) { + XtRemoveInput(filePtr->write); + } + } + if (mask & TCL_EXCEPTION) { + if (!(filePtr->mask & TCL_EXCEPTION)) { + filePtr->except = XtAppAddInput(notifier.appContext, fd, + INT2PTR(XtInputExceptMask), FileProc, filePtr); + } + } else { + if (filePtr->mask & TCL_EXCEPTION) { + XtRemoveInput(filePtr->except); + } + } + filePtr->mask = mask; +} + +/* + *---------------------------------------------------------------------- + * + * DeleteFileHandler -- + * + * Cancel a previously-arranged callback arrangement for a file. + * + * Results: + * None. + * + * Side effects: + * If a callback was previously registered on file, remove it. + * + *---------------------------------------------------------------------- + */ + +static void +DeleteFileHandler( + int fd) /* Stream id for which to remove callback + * procedure. */ +{ + FileHandler *filePtr, *prevPtr; + + if (!initialized) { + InitNotifier(); + } + + TclSetAppContext(NULL); + + /* + * Find the entry for the given file (and return if there isn't one). + */ + + for (prevPtr = NULL, filePtr = notifier.firstFileHandlerPtr; ; + prevPtr = filePtr, filePtr = filePtr->nextPtr) { + if (filePtr == NULL) { + return; + } + if (filePtr->fd == fd) { + break; + } + } + + /* + * Clean up information in the callback record. + */ + + if (prevPtr == NULL) { + notifier.firstFileHandlerPtr = filePtr->nextPtr; + } else { + prevPtr->nextPtr = filePtr->nextPtr; + } + if (filePtr->mask & TCL_READABLE) { + XtRemoveInput(filePtr->read); + } + if (filePtr->mask & TCL_WRITABLE) { + XtRemoveInput(filePtr->write); + } + if (filePtr->mask & TCL_EXCEPTION) { + XtRemoveInput(filePtr->except); + } + ckfree(filePtr); +} + +/* + *---------------------------------------------------------------------- + * + * FileProc -- + * + * These procedures are called by Xt when a file becomes readable, + * writable, or has an exception. + * + * Results: + * None. + * + * Side effects: + * Makes an entry on the Tcl event queue if the event is interesting. + * + *---------------------------------------------------------------------- + */ + +static void +FileProc( + XtPointer clientData, + int *fd, + XtInputId *id) +{ + FileHandler *filePtr = (FileHandler *)clientData; + FileHandlerEvent *fileEvPtr; + int mask = 0; + + /* + * Determine which event happened. + */ + + if (*id == filePtr->read) { + mask = TCL_READABLE; + } else if (*id == filePtr->write) { + mask = TCL_WRITABLE; + } else if (*id == filePtr->except) { + mask = TCL_EXCEPTION; + } + + /* + * Ignore unwanted or duplicate events. + */ + + if (!(filePtr->mask & mask) || (filePtr->readyMask & mask)) { + return; + } + + /* + * This is an interesting event, so put it onto the event queue. + */ + + filePtr->readyMask |= mask; + fileEvPtr = ckalloc(sizeof(FileHandlerEvent)); + fileEvPtr->header.proc = FileHandlerEventProc; + fileEvPtr->fd = filePtr->fd; + Tcl_QueueEvent((Tcl_Event *) fileEvPtr, TCL_QUEUE_TAIL); + + /* + * Process events on the Tcl event queue before returning to Xt. + */ + + Tcl_ServiceAll(); +} + +/* + *---------------------------------------------------------------------- + * + * FileHandlerEventProc -- + * + * This procedure is called by Tcl_ServiceEvent when a file event reaches + * the front of the event queue. This procedure is responsible for + * actually handling the event by invoking the callback for the file + * handler. + * + * Results: + * Returns 1 if the event was handled, meaning it should be removed from + * the queue. Returns 0 if the event was not handled, meaning it should + * stay on the queue. The only time the event isn't handled is if the + * TCL_FILE_EVENTS flag bit isn't set. + * + * Side effects: + * Whatever the file handler's callback procedure does. + * + *---------------------------------------------------------------------- + */ + +static int +FileHandlerEventProc( + Tcl_Event *evPtr, /* Event to service. */ + int flags) /* Flags that indicate what events to handle, + * such as TCL_FILE_EVENTS. */ +{ + FileHandler *filePtr; + FileHandlerEvent *fileEvPtr = (FileHandlerEvent *) evPtr; + int mask; + + if (!(flags & TCL_FILE_EVENTS)) { + return 0; + } + + /* + * 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. + */ + + for (filePtr = notifier.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 + * time when the event was queued, so AND the ready mask with the + * desired mask. + * 2. The file could have been closed and re-opened since the time + * when the event was queued. This is why the ready mask is stored + * in the file handler rather than the queued event: it will be + * zeroed when a new file handler is created for the newly opened + * file. + */ + + mask = filePtr->readyMask & filePtr->mask; + filePtr->readyMask = 0; + if (mask != 0) { + filePtr->proc(filePtr->clientData, mask); + } + break; + } + return 1; +} + +/* + *---------------------------------------------------------------------- + * + * WaitForEvent -- + * + * This function is called by Tcl_DoOneEvent to wait for new events on + * the message queue. If the block time is 0, then Tcl_WaitForEvent just + * polls without blocking. + * + * Results: + * Returns 1 if an event was found, else 0. This ensures that + * Tcl_DoOneEvent will return 1, even if the event is handled by non-Tcl + * code. + * + * Side effects: + * Queues file events that are detected by the select. + * + *---------------------------------------------------------------------- + */ + +static int +WaitForEvent( + const Tcl_Time *timePtr) /* Maximum block time, or NULL. */ +{ + int timeout; + + if (!initialized) { + InitNotifier(); + } + + TclSetAppContext(NULL); + + if (timePtr) { + timeout = timePtr->sec * 1000 + timePtr->usec / 1000; + if (timeout == 0) { + if (XtAppPending(notifier.appContext)) { + goto process; + } else { + return 0; + } + } else { + Tcl_SetTimer(timePtr); + } + } + + process: + XtAppProcessEvent(notifier.appContext, XtIMAll); + return 1; +} + +/* + * Local Variables: + * mode: c + * c-basic-offset: 4 + * fill-column: 78 + * End: + */ |