diff options
Diffstat (limited to 'macosx/tclMacOSXNotify.c')
| -rw-r--r-- | macosx/tclMacOSXNotify.c | 1030 |
1 files changed, 1030 insertions, 0 deletions
diff --git a/macosx/tclMacOSXNotify.c b/macosx/tclMacOSXNotify.c new file mode 100644 index 0000000..bf3b9bc --- /dev/null +++ b/macosx/tclMacOSXNotify.c @@ -0,0 +1,1030 @@ +/* + * tclMacOSXNotify.c -- + * + * This file contains the implementation of a merged + * CFRunLoop/select-based 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. + * Copyright 2001, Apple Computer, Inc. + * Copyright 2005, Tcl Core Team. + * + * See the file "license.terms" for information on usage and redistribution + * of this file, and for a DISCLAIMER OF ALL WARRANTIES. + * + * RCS: @(#) $Id: tclMacOSXNotify.c,v 1.1.2.2 2005/05/14 20:52:31 das Exp $ + */ + +#ifdef HAVE_COREFOUNDATION /* Traditional unix select-based notifier + * is in tclUnixNotfy.c */ +#include "tclInt.h" +#include "tclPort.h" +#include <CoreFoundation/CoreFoundation.h> +#include <pthread.h> + +extern TclStubs tclStubs; +extern Tcl_NotifierProcs tclOriginalNotifier; + +/* + * 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; /* Mask of events that have been seen since the + * last time file handlers were invoked for + * this file. */ + 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 structure contains a set of select() masks to track + * readable, writable, and exceptional conditions. + */ + +typedef struct SelectMasks { + fd_set readable; + fd_set writable; + fd_set exceptional; +} SelectMasks; + +/* + * The following static structure contains the state information for the + * select based implementation of the Tcl notifier. One of these structures + * is created for each thread that is using the notifier. + */ + +typedef struct ThreadSpecificData { + FileHandler *firstFileHandlerPtr; + /* Pointer to head of file handler list. */ + + SelectMasks checkMasks; /* This structure 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_CreateFileHandler. */ + SelectMasks readyMasks; /* This array reflects the readable/writable + * conditions that were found to exist by the + * last call to select. */ + int numFdBits; /* Number of valid bits in checkMasks + * (one more than highest fd for which + * Tcl_WatchFile has been called). */ + int onList; /* True if it is in this list */ + unsigned int pollState; /* pollState is used to implement a polling + * handshake between each thread and the + * notifier thread. Bits defined below. */ + struct ThreadSpecificData *nextPtr, *prevPtr; + /* All threads that are currently waiting on + * an event have their ThreadSpecificData + * structure on a doubly-linked listed formed + * from these pointers. You must hold the + * notifierLock before accessing these + * fields. */ + CFRunLoopSourceRef runLoopSource; + /* Any other thread alerts a notifier + * that an event is ready to be processed + * by signaling this CFRunLoopSource. */ + CFRunLoopRef runLoop; /* This thread's CFRunLoop, needs to be woken + * up whenever the runLoopSource is signaled. */ + int eventReady; /* True if an event is ready to be processed. */ +} ThreadSpecificData; + +static Tcl_ThreadDataKey dataKey; + +/* + * The following static indicates the number of threads that have + * initialized notifiers. + * + * You must hold the notifierInitLock before accessing this variable. + */ + +static int notifierCount = 0; + +/* + * The following variable points to the head of a doubly-linked list of + * of ThreadSpecificData structures for all threads that are currently + * waiting on an event. + * + * You must hold the notifierLock before accessing this list. + */ + +static ThreadSpecificData *waitingListPtr = NULL; + +/* + * The notifier thread spends all its time in select() waiting for a + * file descriptor associated with one of the threads on the waitingListPtr + * list to do something interesting. But if the contents of the + * waitingListPtr list ever changes, we need to wake up and restart + * the select() system call. You can wake up the notifier thread by + * writing a single byte to the file descriptor defined below. This + * file descriptor is the input-end of a pipe and the notifier thread is + * listening for data on the output-end of the same pipe. Hence writing + * to this file descriptor will cause the select() system call to return + * and wake up the notifier thread. + * + * You must hold the notifierLock lock before writing to the pipe. + */ + +static int triggerPipe = -1; +static int receivePipe = -1; /* Output end of triggerPipe */ + +/* + * We use Darwin-native spinlocks instead of pthread mutexes for notifier + * locking: this radically simplifies the implementation and lowers + * overhead. Note that these are not pure spinlocks, they employ various + * strategies to back off, making them immune to most priority-inversion + * livelocks (c.f. man 3 OSSpinLockLock). + */ + +#if defined(HAVE_LIBKERN_OSATOMIC_H) && defined(HAVE_OSSPINLOCKLOCK) +/* Use OSSpinLock API where available (Tiger or later) */ +#include <libkern/OSAtomic.h> +#else +/* Otherwise, use commpage spinlock SPI directly */ +typedef uint32_t OSSpinLock; +extern void _spin_lock(OSSpinLock *lock); +extern void _spin_unlock(OSSpinLock *lock); +#define OSSpinLockLock(p) _spin_lock(p) +#define OSSpinLockUnlock(p) _spin_unlock(p) +#endif + +/* + * These spinlocks lock access to the global notifier state. + */ + +static OSSpinLock notifierInitLock = 0; +static OSSpinLock notifierLock = 0; + +/* + * Macros abstracting notifier locking/unlocking + */ + +#define LOCK_NOTIFIER_INIT OSSpinLockLock(¬ifierInitLock) +#define UNLOCK_NOTIFIER_INIT OSSpinLockUnlock(¬ifierInitLock) +#define LOCK_NOTIFIER OSSpinLockLock(¬ifierLock) +#define UNLOCK_NOTIFIER OSSpinLockUnlock(¬ifierLock) + +/* + * The pollState bits + * POLL_WANT is set by each thread before it waits on its condition + * variable. It is checked by the notifier before it does + * select. + * POLL_DONE is set by the notifier if it goes into select after + * seeing POLL_WANT. The idea is to ensure it tries a select + * with the same bits the initial thread had set. + */ +#define POLL_WANT 0x1 +#define POLL_DONE 0x2 + +/* + * This is the thread ID of the notifier thread that does select. + */ +static pthread_t notifierThread; + +/* + * Static routines defined in this file. + */ + +static void NotifierThreadProc(ClientData clientData); +static int FileHandlerEventProc(Tcl_Event *evPtr, int flags); + +/* + *---------------------------------------------------------------------- + * + * Tcl_InitNotifier -- + * + * Initializes the platform specific notifier state. + * + * Results: + * Returns a handle to the notifier state for this thread.. + * + * Side effects: + * None. + * + *---------------------------------------------------------------------- + */ + +ClientData +Tcl_InitNotifier() +{ + ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); + + tsdPtr->eventReady = 0; + + /* + * Initialize CFRunLoopSource and add it to CFRunLoop of this thread + */ + + if (!tsdPtr->runLoop) { + CFRunLoopRef runLoop = CFRunLoopGetCurrent(); + CFRunLoopSourceRef runLoopSource; + CFRunLoopSourceContext runLoopSourceContext; + + bzero(&runLoopSourceContext, sizeof(CFRunLoopSourceContext)); + runLoopSourceContext.info = tsdPtr; + runLoopSource = CFRunLoopSourceCreate(NULL, 0, &runLoopSourceContext); + if (!runLoopSource) { + Tcl_Panic("Tcl_InitNotifier: could not create CFRunLoopSource."); + } + CFRunLoopAddSource(runLoop, runLoopSource, kCFRunLoopCommonModes); + CFRelease(runLoopSource); + tsdPtr->runLoopSource = runLoopSource; + tsdPtr->runLoop = runLoop; + } + + /* + * Initialize trigger pipe and start the Notifier thread if necessary. + */ + + LOCK_NOTIFIER_INIT; + if (notifierCount == 0) { + int fds[2], status, result; + pthread_attr_t attr; + + if (pipe(fds) != 0) { + Tcl_Panic("Tcl_InitNotifier: could not create trigger pipe."); + } + + status = fcntl(fds[0], F_GETFL); + status |= O_NONBLOCK; + if (fcntl(fds[0], F_SETFL, status) < 0) { + Tcl_Panic("Tcl_InitNotifier: could not make receive pipe non blocking."); + } + status = fcntl(fds[1], F_GETFL); + status |= O_NONBLOCK; + if (fcntl(fds[1], F_SETFL, status) < 0) { + Tcl_Panic("Tcl_InitNotifier: could not make trigger pipe non blocking."); + } + + receivePipe = fds[0]; + triggerPipe = fds[1]; + + pthread_attr_init(&attr); + pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEM); + pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE); + pthread_attr_setstacksize(&attr, 60 * 1024); + result = pthread_create(¬ifierThread, &attr, (void * (*)(void *))NotifierThreadProc, NULL); + pthread_attr_destroy(&attr); + if (result) { + Tcl_Panic("Tcl_InitNotifier: unable to start notifier thread."); + } + } + notifierCount++; + UNLOCK_NOTIFIER_INIT; + + return (ClientData) tsdPtr; +} + +/* + *---------------------------------------------------------------------- + * + * Tcl_FinalizeNotifier -- + * + * This function is called to cleanup the notifier state before + * a thread is terminated. + * + * Results: + * None. + * + * Side effects: + * May terminate the background notifier thread if this is the + * last notifier instance. + * + *---------------------------------------------------------------------- + */ + +void +Tcl_FinalizeNotifier(clientData) + ClientData clientData; /* Not used. */ +{ + ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); + + LOCK_NOTIFIER_INIT; + notifierCount--; + + /* + * If this is the last thread to use the notifier, close the notifier + * pipe and wait for the background thread to terminate. + */ + + if (notifierCount == 0) { + int result; + + if (triggerPipe < 0) { + Tcl_Panic("Tcl_FinalizeNotifier: notifier pipe not initialized."); + } + + /* + * Send "q" message to the notifier thread so that it will + * terminate. The notifier will return from its call to select() + * and notice that a "q" message has arrived, it will then close + * its side of the pipe and terminate its thread. Note the we can + * not just close the pipe and check for EOF in the notifier + * thread because if a background child process was created with + * exec, select() would not register the EOF on the pipe until the + * child processes had terminated. [Bug: 4139] + */ + write(triggerPipe, "q", 1); + close(triggerPipe); + + result = pthread_join(notifierThread, NULL); + if (result) { + Tcl_Panic("Tcl_FinalizeNotifier: unable to join notifier thread."); + } + + close(receivePipe); + triggerPipe = -1; + } + UNLOCK_NOTIFIER_INIT; + + LOCK_NOTIFIER; /* for concurrency with Tcl_AlertNotifier */ + if (tsdPtr->runLoop) { + tsdPtr->runLoop = NULL; + /* Remove runLoopSource from all CFRunLoops and release it */ + CFRunLoopSourceInvalidate(tsdPtr->runLoopSource); + tsdPtr->runLoopSource = NULL; + } + UNLOCK_NOTIFIER; +} + +/* + *---------------------------------------------------------------------- + * + * Tcl_AlertNotifier -- + * + * Wake up the specified notifier from any thread. This routine + * is called by the platform independent notifier code whenever + * the Tcl_ThreadAlert routine is called. This routine is + * guaranteed not to be called on a given notifier after + * Tcl_FinalizeNotifier is called for that notifier. + * + * Results: + * None. + * + * Side effects: + * Signals the notifier condition variable for the specified + * notifier. + * + *---------------------------------------------------------------------- + */ + +void +Tcl_AlertNotifier(clientData) + ClientData clientData; +{ + ThreadSpecificData *tsdPtr = (ThreadSpecificData *) clientData; + LOCK_NOTIFIER; + if (tsdPtr->runLoop) { + tsdPtr->eventReady = 1; + CFRunLoopSourceSignal(tsdPtr->runLoopSource); + CFRunLoopWakeUp(tsdPtr->runLoop); + } + UNLOCK_NOTIFIER; +} + +/* + *---------------------------------------------------------------------- + * + * Tcl_SetTimer -- + * + * This procedure sets the current notifier timer value. This + * interface is not implemented in this notifier because we are + * always running inside of Tcl_DoOneEvent. + * + * Results: + * None. + * + * 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. + */ + + if (tclStubs.tcl_SetTimer != tclOriginalNotifier.setTimerProc) { + tclStubs.tcl_SetTimer(timePtr); + } +} + +/* + *---------------------------------------------------------------------- + * + * Tcl_ServiceModeHook -- + * + * This function is invoked whenever the service mode changes. + * + * Results: + * None. + * + * Side effects: + * None. + * + *---------------------------------------------------------------------- + */ + +void +Tcl_ServiceModeHook(mode) + int mode; /* Either TCL_SERVICE_ALL, or + * TCL_SERVICE_NONE. */ +{ +} + +/* + *---------------------------------------------------------------------- + * + * Tcl_CreateFileHandler -- + * + * This procedure registers a file handler with the select notifier. + * + * Results: + * 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; /* Procedure 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; + } + + for (filePtr = tsdPtr->firstFileHandlerPtr; filePtr != NULL; + filePtr = filePtr->nextPtr) { + if (filePtr->fd == fd) { + break; + } + } + if (filePtr == NULL) { + filePtr = (FileHandler*) ckalloc(sizeof(FileHandler)); + filePtr->fd = fd; + filePtr->readyMask = 0; + filePtr->nextPtr = tsdPtr->firstFileHandlerPtr; + tsdPtr->firstFileHandlerPtr = filePtr; + } + filePtr->proc = proc; + filePtr->clientData = clientData; + filePtr->mask = mask; + + /* + * Update the check masks for this file. + */ + + if (mask & TCL_READABLE) { + FD_SET(fd, &(tsdPtr->checkMasks.readable)); + } else { + FD_CLR(fd, &(tsdPtr->checkMasks.readable)); + } + if (mask & TCL_WRITABLE) { + FD_SET(fd, &(tsdPtr->checkMasks.writable)); + } else { + FD_CLR(fd, &(tsdPtr->checkMasks.writable)); + } + if (mask & TCL_EXCEPTION) { + FD_SET(fd, &(tsdPtr->checkMasks.exceptional)); + } else { + FD_CLR(fd, &(tsdPtr->checkMasks.exceptional)); + } + if (tsdPtr->numFdBits <= fd) { + tsdPtr->numFdBits = fd+1; + } +} + +/* + *---------------------------------------------------------------------- + * + * Tcl_DeleteFileHandler -- + * + * Cancel a previously-arranged callback arrangement for + * a file. + * + * Results: + * None. + * + * 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 procedure. */ +{ + FileHandler *filePtr, *prevPtr; + int i; + ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); + + if (tclStubs.tcl_DeleteFileHandler != tclOriginalNotifier.deleteFileHandlerProc) { + tclStubs.tcl_DeleteFileHandler(fd); + return; + } + + /* + * Find the entry for the given file (and return if there isn't one). + */ + + for (prevPtr = NULL, filePtr = tsdPtr->firstFileHandlerPtr; ; + prevPtr = filePtr, filePtr = filePtr->nextPtr) { + if (filePtr == NULL) { + return; + } + if (filePtr->fd == fd) { + break; + } + } + + /* + * Update the check masks for this file. + */ + + if (filePtr->mask & TCL_READABLE) { + FD_CLR(fd, &(tsdPtr->checkMasks.readable)); + } + if (filePtr->mask & TCL_WRITABLE) { + FD_CLR(fd, &(tsdPtr->checkMasks.writable)); + } + if (filePtr->mask & TCL_EXCEPTION) { + FD_CLR(fd, &(tsdPtr->checkMasks.exceptional)); + } + + /* + * Find current max fd. + */ + + if (fd+1 == tsdPtr->numFdBits) { + tsdPtr->numFdBits = 0; + for (i = fd-1; i >= 0; i--) { + if (FD_ISSET(i, &(tsdPtr->checkMasks.readable)) + || FD_ISSET(i, &(tsdPtr->checkMasks.writable)) + || FD_ISSET(i, &(tsdPtr->checkMasks.exceptional))) { + tsdPtr->numFdBits = i+1; + break; + } + } + } + + /* + * Clean up information in the callback record. + */ + + if (prevPtr == NULL) { + tsdPtr->firstFileHandlerPtr = filePtr->nextPtr; + } else { + prevPtr->nextPtr = filePtr->nextPtr; + } + ckfree((char *) filePtr); +} + +/* + *---------------------------------------------------------------------- + * + * 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(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; + + 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. + */ + + tsdPtr = TCL_TSD_INIT(&dataKey); + for (filePtr = tsdPtr->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; +} + +/* + *---------------------------------------------------------------------- + * + * Tcl_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 the select would block forever, otherwise + * returns 0. + * + * 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; + int waitForFiles; + ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); + + if (tclStubs.tcl_WaitForEvent != tclOriginalNotifier.waitForEventProc) { + return tclStubs.tcl_WaitForEvent(timePtr); + } + + /* + * Place this thread on the list of interested threads, signal the + * notifier thread, and wait for a response or a timeout. + */ + + LOCK_NOTIFIER; + + waitForFiles = (tsdPtr->numFdBits > 0); + if (timePtr != NULL && timePtr->sec == 0 && timePtr->usec == 0) { + /* + * Cannot emulate a polling select with a polling condition variable. + * Instead, pretend to wait for files and tell the notifier + * thread what we are doing. The notifier thread makes sure + * it goes through select with its select mask in the same state + * as ours currently is. We block until that happens. + */ + + waitForFiles = 1; + tsdPtr->pollState = POLL_WANT; + timePtr = NULL; + } else { + tsdPtr->pollState = 0; + } + + if (waitForFiles) { + /* + * Add the ThreadSpecificData structure of this thread to the list + * of ThreadSpecificData structures of all threads that are waiting + * on file events. + */ + + tsdPtr->nextPtr = waitingListPtr; + if (waitingListPtr) { + waitingListPtr->prevPtr = tsdPtr; + } + tsdPtr->prevPtr = 0; + waitingListPtr = tsdPtr; + tsdPtr->onList = 1; + + write(triggerPipe, "", 1); + } + + FD_ZERO(&(tsdPtr->readyMasks.readable)); + FD_ZERO(&(tsdPtr->readyMasks.writable)); + FD_ZERO(&(tsdPtr->readyMasks.exceptional)); + + if (!tsdPtr->eventReady) { + CFTimeInterval waitTime; + + if (timePtr == NULL) { + waitTime = 1.0e10; /* Wait forever, as per CFRunLoop.c */ + } else { + waitTime = timePtr->sec + 1.0e-6 * timePtr->usec; + } + UNLOCK_NOTIFIER; + CFRunLoopRunInMode(kCFRunLoopDefaultMode, waitTime, TRUE); + LOCK_NOTIFIER; + } + tsdPtr->eventReady = 0; + + if (waitForFiles && tsdPtr->onList) { + /* + * Remove the ThreadSpecificData structure of this thread from the + * waiting list. Alert the notifier thread to recompute its select + * masks - skipping this caused a hang when trying to close a pipe + * which the notifier thread was still doing a select on. + */ + + if (tsdPtr->prevPtr) { + tsdPtr->prevPtr->nextPtr = tsdPtr->nextPtr; + } else { + waitingListPtr = tsdPtr->nextPtr; + } + if (tsdPtr->nextPtr) { + tsdPtr->nextPtr->prevPtr = tsdPtr->prevPtr; + } + tsdPtr->nextPtr = tsdPtr->prevPtr = NULL; + tsdPtr->onList = 0; + write(triggerPipe, "", 1); + } + + + /* + * Queue all detected file events before returning. + */ + + for (filePtr = tsdPtr->firstFileHandlerPtr; (filePtr != NULL); + filePtr = filePtr->nextPtr) { + + mask = 0; + if (FD_ISSET(filePtr->fd, &(tsdPtr->readyMasks.readable))) { + mask |= TCL_READABLE; + } + if (FD_ISSET(filePtr->fd, &(tsdPtr->readyMasks.writable))) { + mask |= TCL_WRITABLE; + } + if (FD_ISSET(filePtr->fd, &(tsdPtr->readyMasks.exceptional))) { + mask |= TCL_EXCEPTION; + } + + if (!mask) { + continue; + } + + /* + * Don't bother to queue an event if the mask was previously + * non-zero since an event must still be on the queue. + */ + + if (filePtr->readyMask == 0) { + fileEvPtr = (FileHandlerEvent *) ckalloc(sizeof(FileHandlerEvent)); + fileEvPtr->header.proc = FileHandlerEventProc; + fileEvPtr->fd = filePtr->fd; + Tcl_QueueEvent((Tcl_Event *) fileEvPtr, TCL_QUEUE_TAIL); + } + filePtr->readyMask = mask; + } + UNLOCK_NOTIFIER; + return 0; +} + +/* + *---------------------------------------------------------------------- + * + * NotifierThreadProc -- + * + * This routine is the initial (and only) function executed by the + * special notifier thread. Its job is to wait for file descriptors + * to become readable or writable or to have an exception condition + * and then to notify other threads who are interested in this + * information by signalling a condition variable. Other threads + * can signal this notifier thread of a change in their interests + * by writing a single byte to a special pipe that the notifier + * thread is monitoring. + * + * Result: + * None. Once started, this routine never exits. It dies with + * the overall process. + * + * Side effects: + * 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 i, numFdBits = 0; + long found; + struct timeval poll = {0., 0.}, *timePtr; + char buf[2]; + + /* + * Look for file events and report them to interested threads. + */ + + while (1) { + FD_ZERO(&readableMask); + FD_ZERO(&writableMask); + FD_ZERO(&exceptionalMask); + + /* + * Compute the logical OR of the select masks from all the + * waiting notifiers. + */ + + LOCK_NOTIFIER; + timePtr = NULL; + for (tsdPtr = waitingListPtr; tsdPtr; tsdPtr = tsdPtr->nextPtr) { + for (i = tsdPtr->numFdBits-1; i >= 0; --i) { + if (FD_ISSET(i, &(tsdPtr->checkMasks.readable))) { + FD_SET(i, &readableMask); + } + if (FD_ISSET(i, &(tsdPtr->checkMasks.writable))) { + FD_SET(i, &writableMask); + } + if (FD_ISSET(i, &(tsdPtr->checkMasks.exceptional))) { + FD_SET(i, &exceptionalMask); + } + } + if (tsdPtr->numFdBits > numFdBits) { + numFdBits = tsdPtr->numFdBits; + } + if (tsdPtr->pollState & POLL_WANT) { + /* + * Here we make sure we go through select() with the same + * mask bits that were present when the thread tried to poll. + */ + + tsdPtr->pollState |= POLL_DONE; + timePtr = &poll; + } + } + UNLOCK_NOTIFIER; + + /* + * Set up the select mask to include the receive pipe. + */ + + if (receivePipe >= numFdBits) { + numFdBits = receivePipe + 1; + } + FD_SET(receivePipe, &readableMask); + + if (select(numFdBits, &readableMask, &writableMask, &exceptionalMask, + timePtr) == -1) { + /* + * Try again immediately on an error. + */ + + continue; + } + + /* + * Alert any threads that are waiting on a ready file descriptor. + */ + + LOCK_NOTIFIER; + for (tsdPtr = waitingListPtr; tsdPtr; tsdPtr = tsdPtr->nextPtr) { + found = 0; + + for (i = tsdPtr->numFdBits-1; i >= 0; --i) { + if (FD_ISSET(i, &(tsdPtr->checkMasks.readable)) + && FD_ISSET(i, &readableMask)) { + FD_SET(i, &(tsdPtr->readyMasks.readable)); + found = 1; + } + if (FD_ISSET(i, &(tsdPtr->checkMasks.writable)) + && FD_ISSET(i, &writableMask)) { + FD_SET(i, &(tsdPtr->readyMasks.writable)); + found = 1; + } + if (FD_ISSET(i, &(tsdPtr->checkMasks.exceptional)) + && FD_ISSET(i, &exceptionalMask)) { + FD_SET(i, &(tsdPtr->readyMasks.exceptional)); + found = 1; + } + } + + if (found || (tsdPtr->pollState & POLL_DONE)) { + tsdPtr->eventReady = 1; + if (tsdPtr->onList) { + /* + * Remove the ThreadSpecificData structure of this + * thread from the waiting list. This prevents us from + * continuously spining on select until the other + * threads runs and services the file event. + */ + + if (tsdPtr->prevPtr) { + tsdPtr->prevPtr->nextPtr = tsdPtr->nextPtr; + } else { + waitingListPtr = tsdPtr->nextPtr; + } + if (tsdPtr->nextPtr) { + tsdPtr->nextPtr->prevPtr = tsdPtr->prevPtr; + } + tsdPtr->nextPtr = tsdPtr->prevPtr = NULL; + tsdPtr->onList = 0; + tsdPtr->pollState = 0; + } + if (tsdPtr->runLoop) { + CFRunLoopSourceSignal(tsdPtr->runLoopSource); + CFRunLoopWakeUp(tsdPtr->runLoop); + } + } + } + UNLOCK_NOTIFIER; + + /* + * Consume the next byte from the notifier pipe if the pipe was + * readable. Note that there may be multiple bytes pending, but + * to avoid a race condition we only read one at a time. + */ + + if (FD_ISSET(receivePipe, &readableMask)) { + i = read(receivePipe, buf, 1); + + if ((i == 0) || ((i == 1) && (buf[0] == 'q'))) { + /* + * Someone closed the write end of the pipe or sent us a + * Quit message [Bug: 4139] and then closed the write end + * of the pipe so we need to shut down the notifier thread. + */ + + break; + } + } + } + pthread_exit (0); +} + +#endif /* HAVE_COREFOUNDATION */ |