/* * 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 1.2 2005/05/19 13:27:28 das Exp $ */ #ifdef HAVE_COREFOUNDATION /* Traditional unix select-based notifier * is in tclUnixNotfy.c */ #include "tclInt.h" #include #include 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 #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); 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); CFRelease(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; Tcl_Time myTime; int waitForFiles; Tcl_Time *myTimePtr; ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey); if (tclStubs.tcl_WaitForEvent != tclOriginalNotifier.waitForEventProc) { return tclStubs.tcl_WaitForEvent(timePtr); } if (timePtr != NULL) { /* TIP #233 (Virtualized Time). Is virtual time in effect ? * And do we actually have something to scale ? If yes to both * then we call the handler to do this scaling */ myTime.sec = timePtr->sec; myTime.usec = timePtr->usec; if (myTime.sec != 0 || myTime.usec != 0) { (*tclScaleTimeProcPtr) (&myTime, tclTimeClientData); } myTimePtr = &myTime; } else { myTimePtr = NULL; } /* * 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 (myTimePtr != NULL && myTimePtr->sec == 0 && myTimePtr->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; myTimePtr = 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 (myTimePtr == NULL) { waitTime = 1.0e10; /* Wait forever, as per CFRunLoop.c */ } else { waitTime = myTimePtr->sec + 1.0e-6 * myTimePtr->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 */