tclwinpipe.c

来自「tcl是工具命令语言」· C语言 代码 · 共 2,329 行 · 第 1/5 页

 * Side effects:
 *	Closes the physical channel.
 *
 *----------------------------------------------------------------------
 */

static int
PipeClose2Proc(
    ClientData instanceData,	/* Pointer to PipeInfo structure. */
    Tcl_Interp *interp,		/* For error reporting. */
    int flags)			/* Flags that indicate which side to close. */
{
    PipeInfo *pipePtr = (PipeInfo *) instanceData;
    Tcl_Channel errChan;
    int errorCode, result;
    PipeInfo *infoPtr, **nextPtrPtr;
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
    DWORD exitCode;

    errorCode = 0;
    if ((!flags || (flags == TCL_CLOSE_READ))
	    && (pipePtr->readFile != NULL)) {
	/*
	 * Clean up the background thread if necessary.  Note that this
	 * must be done before we can close the file, since the 
	 * thread may be blocking trying to read from the pipe.
	 */

	if (pipePtr->readThread) {
	    /*
	     * The thread may already have closed on it's own.  Check it's
	     * exit code.
	     */

	    GetExitCodeThread(pipePtr->readThread, &exitCode);

	    if (exitCode == STILL_ACTIVE) {
		/*
		 * Set the stop event so that if the reader thread is blocked
		 * in PipeReaderThread on WaitForMultipleEvents, it will exit
		 * cleanly.
		 */

		SetEvent(pipePtr->stopReader);

		/*
		 * Wait at most 20 milliseconds for the reader thread to close.
		 */

		if (WaitForSingleObject(pipePtr->readThread, 20)
			== WAIT_TIMEOUT) {
		    /*
		     * The thread must be blocked waiting for the pipe to
		     * become readable in ReadFile().  There isn't a clean way
		     * to exit the thread from this condition.  We should
		     * terminate the child process instead to get the reader
		     * thread to fall out of ReadFile with a FALSE.  (below) is
		     * not the correct way to do this, but will stay here until
		     * a better solution is found.
		     *
		     * Note that we need to guard against terminating the
		     * thread while it is in the middle of Tcl_ThreadAlert
		     * because it won't be able to release the notifier lock.
		     */

		    Tcl_MutexLock(&pipeMutex);

		    /* BUG: this leaks memory */
		    TerminateThread(pipePtr->readThread, 0);
		    Tcl_MutexUnlock(&pipeMutex);
		}
	    }

	    CloseHandle(pipePtr->readThread);
	    CloseHandle(pipePtr->readable);
	    CloseHandle(pipePtr->startReader);
	    CloseHandle(pipePtr->stopReader);
	    pipePtr->readThread = NULL;
	}
	if (TclpCloseFile(pipePtr->readFile) != 0) {
	    errorCode = errno;
	}
	pipePtr->validMask &= ~TCL_READABLE;
	pipePtr->readFile = NULL;
    }
    if ((!flags || (flags & TCL_CLOSE_WRITE))
	    && (pipePtr->writeFile != NULL)) {

	if (pipePtr->writeThread) {
	    /*
	     * Wait for the writer thread to finish the current buffer,
	     * then terminate the thread and close the handles.  If the
	     * channel is nonblocking, there should be no pending write
	     * operations.
	     */

	    WaitForSingleObject(pipePtr->writable, INFINITE);

	    /*
	     * The thread may already have closed on it's own.  Check it's
	     * exit code.
	     */

	    GetExitCodeThread(pipePtr->writeThread, &exitCode);

	    if (exitCode == STILL_ACTIVE) {
		/*
		 * Set the stop event so that if the reader thread is blocked
		 * in PipeReaderThread on WaitForMultipleEvents, it will exit
		 * cleanly.
		 */

		SetEvent(pipePtr->stopWriter);

		/*
		 * Wait at most 20 milliseconds for the reader thread to close.
		 */

		if (WaitForSingleObject(pipePtr->writeThread, 20)
			== WAIT_TIMEOUT) {
		    /*
		     * The thread must be blocked waiting for the pipe to
		     * consume input in WriteFile().  There isn't a clean way
		     * to exit the thread from this condition.  We should
		     * terminate the child process instead to get the writer
		     * thread to fall out of WriteFile with a FALSE.  (below) is
		     * not the correct way to do this, but will stay here until
		     * a better solution is found.
		     *
		     * Note that we need to guard against terminating the
		     * thread while it is in the middle of Tcl_ThreadAlert
		     * because it won't be able to release the notifier lock.
		     */

		    Tcl_MutexLock(&pipeMutex);

		    /* BUG: this leaks memory */
		    TerminateThread(pipePtr->writeThread, 0);
		    Tcl_MutexUnlock(&pipeMutex);
		}
	    }

	    CloseHandle(pipePtr->writeThread);
	    CloseHandle(pipePtr->writable);
	    CloseHandle(pipePtr->startWriter);
	    CloseHandle(pipePtr->stopWriter);
	    pipePtr->writeThread = NULL;
	}
	if (TclpCloseFile(pipePtr->writeFile) != 0) {
	    if (errorCode == 0) {
		errorCode = errno;
	    }
	}
	pipePtr->validMask &= ~TCL_WRITABLE;
	pipePtr->writeFile = NULL;
    }

    pipePtr->watchMask &= pipePtr->validMask;

    /*
     * Don't free the channel if any of the flags were set.
     */

    if (flags) {
	return errorCode;
    }

    /*
     * Remove the file from the list of watched files.
     */

    for (nextPtrPtr = &(tsdPtr->firstPipePtr), infoPtr = *nextPtrPtr;
	    infoPtr != NULL;
	    nextPtrPtr = &infoPtr->nextPtr, infoPtr = *nextPtrPtr) {
	if (infoPtr == (PipeInfo *)pipePtr) {
	    *nextPtrPtr = infoPtr->nextPtr;
	    break;
	}
    }

    /*
     * Wrap the error file into a channel and give it to the cleanup
     * routine.
     */

    if (pipePtr->errorFile) {
	WinFile *filePtr;

	filePtr = (WinFile*)pipePtr->errorFile;
	errChan = Tcl_MakeFileChannel((ClientData) filePtr->handle,
		TCL_READABLE);
	ckfree((char *) filePtr);
    } else {
        errChan = NULL;
    }

    result = TclCleanupChildren(interp, pipePtr->numPids, pipePtr->pidPtr,
            errChan);

    if (pipePtr->numPids > 0) {
        ckfree((char *) pipePtr->pidPtr);
    }

    if (pipePtr->writeBuf != NULL) {
	ckfree(pipePtr->writeBuf);
    }

    ckfree((char*) pipePtr);

    if (errorCode == 0) {
        return result;
    }
    return errorCode;
}

/*
 *----------------------------------------------------------------------
 *
 * PipeInputProc --
 *
 *	Reads input from the IO channel into the buffer given. Returns
 *	count of how many bytes were actually read, and an error indication.
 *
 * Results:
 *	A count of how many bytes were read is returned and an error
 *	indication is returned in an output argument.
 *
 * Side effects:
 *	Reads input from the actual channel.
 *
 *----------------------------------------------------------------------
 */

static int
PipeInputProc(
    ClientData instanceData,		/* Pipe state. */
    char *buf,				/* Where to store data read. */
    int bufSize,			/* How much space is available
                                         * in the buffer? */
    int *errorCode)			/* Where to store error code. */
{
    PipeInfo *infoPtr = (PipeInfo *) instanceData;
    WinFile *filePtr = (WinFile*) infoPtr->readFile;
    DWORD count, bytesRead = 0;
    int result;

    *errorCode = 0;
    /*
     * Synchronize with the reader thread.
     */

    result = WaitForRead(infoPtr, (infoPtr->flags & PIPE_ASYNC) ? 0 : 1);

    /*
     * If an error occurred, return immediately.
     */

    if (result == -1) {
	*errorCode = errno;
	return -1;
    }

    if (infoPtr->readFlags & PIPE_EXTRABYTE) {
	/*
	 * The reader thread consumed 1 byte as a side effect of
	 * waiting so we need to move it into the buffer.
	 */

	*buf = infoPtr->extraByte;
	infoPtr->readFlags &= ~PIPE_EXTRABYTE;
	buf++;
	bufSize--;
	bytesRead = 1;

	/*
	 * If further read attempts would block, return what we have.
	 */

	if (result == 0) {
	    return bytesRead;
	}
    }

    /*
     * Attempt to read bufSize bytes.  The read will return immediately
     * if there is any data available.  Otherwise it will block until
     * at least one byte is available or an EOF occurs.
     */

    if (ReadFile(filePtr->handle, (LPVOID) buf, (DWORD) bufSize, &count,
	    (LPOVERLAPPED) NULL) == TRUE) {
	return bytesRead + count;
    } else if (bytesRead) {
	/*
	 * Ignore errors if we have data to return.
	 */

	return bytesRead;
    }

    TclWinConvertError(GetLastError());
    if (errno == EPIPE) {
	infoPtr->readFlags |= PIPE_EOF;
	return 0;
    }
    *errorCode = errno;
    return -1;
}

/*
 *----------------------------------------------------------------------
 *
 * PipeOutputProc --
 *
 *	Writes the given output on the IO channel. Returns count of how
 *	many characters were actually written, and an error indication.
 *
 * Results:
 *	A count of how many characters were written is returned and an
 *	error indication is returned in an output argument.
 *
 * Side effects:
 *	Writes output on the actual channel.
 *
 *----------------------------------------------------------------------
 */

static int
PipeOutputProc(
    ClientData instanceData,		/* Pipe state. */
    CONST char *buf,			/* The data buffer. */
    int toWrite,			/* How many bytes to write? */
    int *errorCode)			/* Where to store error code. */
{
    PipeInfo *infoPtr = (PipeInfo *) instanceData;
    WinFile *filePtr = (WinFile*) infoPtr->writeFile;
    DWORD bytesWritten, timeout;
    
    *errorCode = 0;
    timeout = (infoPtr->flags & PIPE_ASYNC) ? 0 : INFINITE;
    if (WaitForSingleObject(infoPtr->writable, timeout) == WAIT_TIMEOUT) {
	/*
	 * The writer thread is blocked waiting for a write to complete
	 * and the channel is in non-blocking mode.
	 */

	errno = EAGAIN;
	goto error;
    }
    
    /*
     * Check for a background error on the last write.
     */

    if (infoPtr->writeError) {
	TclWinConvertError(infoPtr->writeError);
	infoPtr->writeError = 0;
	goto error;
    }

    if (infoPtr->flags & PIPE_ASYNC) {
	/*
	 * The pipe is non-blocking, so copy the data into the output
	 * buffer and restart the writer thread.
	 */

	if (toWrite > infoPtr->writeBufLen) {
	    /*
	     * Reallocate the buffer to be large enough to hold the data.
	     */

	    if (infoPtr->writeBuf) {
		ckfree(infoPtr->writeBuf);
	    }
	    infoPtr->writeBufLen = toWrite;
	    infoPtr->writeBuf = ckalloc((unsigned int) toWrite);
	}
	memcpy(infoPtr->writeBuf, buf, (size_t) toWrite);
	infoPtr->toWrite = toWrite;
	ResetEvent(infoPtr->writable);
	SetEvent(infoPtr->startWriter);
	bytesWritten = toWrite;
    } else {
	/*
	 * In the blocking case, just try to write the buffer directly.
	 * This avoids an unnecessary copy.
	 */

	if (WriteFile(filePtr->handle, (LPVOID) buf, (DWORD) toWrite,
		&bytesWritten, (LPOVERLAPPED) NULL) == FALSE) {
	    TclWinConvertError(GetLastError());
	    goto error;
	}
    }
    return bytesWritten;

    error:
    *errorCode = errno;
    return -1;

}

/*
 *----------------------------------------------------------------------
 *
 * PipeEventProc --
 *
 *	This function is invoked by Tcl_ServiceEvent when a file event
 *	reaches the front of the event queue.  This procedure invokes
 *	Tcl_NotifyChannel on the pipe.
 *
 * 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 notifier callback does.
 *
 *----------------------------------------------------------------------
 */

static int
PipeEventProc(
    Tcl_Event *evPtr,		/* Event to service. */
    int flags)			/* Flags that indicate what events to
				 * handle, such as TCL_FILE_EVENTS. */
{
    PipeEvent *pipeEvPtr = (PipeEvent *)evPtr;
    PipeInfo *infoPtr;
    WinFile *filePtr;
    int mask;
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);

    if (!(flags & TCL_FILE_EVENTS)) {
	return 0;
    }

    /*
     * Search through the list of watched pipes for the one whose handle
     * matches the event.  We do this rather than simply dereferencing
     * the handle in the event so that pipes can be deleted while the
     * event is in the queue.
     */

    for (infoPtr = tsdPtr->firstPipePtr; infoPtr != NULL;
	    infoPtr = infoPtr->nextPtr) {
	if (pipeEvPtr->infoPtr == infoPtr) {
	    infoPtr->flags &= ~(PIPE_PENDING);
	    break;
	}
    }

    /*
     * Remove stale events.
     */

    if (!infoPtr) {
	return 1;
    }

    /*
     * Check to see if the pipe is readable.  Note
     * that we can't tell if a pipe is writab