tclio.c

linux系统下的音频通信

}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_SetStdChannel --
 *
 *	This function is used to change the channels that are used
 *	for stdin/stdout/stderr in new interpreters.
 *
 * Results:
 *	None
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_SetStdChannel(channel, type)
    Tcl_Channel channel;
    int type;			/* One of TCL_STDIN, TCL_STDOUT, TCL_STDERR. */
{
    switch (type) {
	case TCL_STDIN:
            stdinInitialized = 1;
	    stdinChannel = channel;
	    break;
	case TCL_STDOUT:
	    stdoutInitialized = 1;
	    stdoutChannel = channel;
	    break;
	case TCL_STDERR:
	    stderrInitialized = 1;
	    stderrChannel = channel;
	    break;
    }
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_GetStdChannel --
 *
 *	Returns the specified standard channel.
 *
 * Results:
 *	Returns the specified standard channel, or NULL.
 *
 * Side effects:
 *	May cause the creation of a standard channel and the underlying
 *	file.
 *
 *----------------------------------------------------------------------
 */

Tcl_Channel
Tcl_GetStdChannel(type)
    int type;			/* One of TCL_STDIN, TCL_STDOUT, TCL_STDERR. */
{
    Tcl_Channel channel = NULL;

    /*
     * If the channels were not created yet, create them now and
     * store them in the static variables.  Note that we need to set
     * stdinInitialized before calling TclGetDefaultStdChannel in order
     * to avoid recursive loops when TclGetDefaultStdChannel calls
     * Tcl_CreateChannel.
     */

    switch (type) {
	case TCL_STDIN:
	    if (!stdinInitialized) {
		stdinChannel = TclGetDefaultStdChannel(TCL_STDIN);
		stdinInitialized = 1;

                /*
                 * Artificially bump the refcount to ensure that the channel
                 * is only closed on exit.
                 *
                 * NOTE: Must only do this if stdinChannel is not NULL. It
                 * can be NULL in situations where Tcl is unable to connect
                 * to the standard input.
                 */

                if (stdinChannel != (Tcl_Channel) NULL) {
                    (void) Tcl_RegisterChannel((Tcl_Interp *) NULL,
                            stdinChannel);
                }
	    }
	    channel = stdinChannel;
	    break;
	case TCL_STDOUT:
	    if (!stdoutInitialized) {
		stdoutChannel = TclGetDefaultStdChannel(TCL_STDOUT);
		stdoutInitialized = 1;

                /*
                 * Artificially bump the refcount to ensure that the channel
                 * is only closed on exit.
                 *
                 * NOTE: Must only do this if stdoutChannel is not NULL. It
                 * can be NULL in situations where Tcl is unable to connect
                 * to the standard output.
                 */

                if (stdoutChannel != (Tcl_Channel) NULL) {
                    (void) Tcl_RegisterChannel((Tcl_Interp *) NULL,
                            stdoutChannel);
                }
	    }
	    channel = stdoutChannel;
	    break;
	case TCL_STDERR:
	    if (!stderrInitialized) {
		stderrChannel = TclGetDefaultStdChannel(TCL_STDERR);
		stderrInitialized = 1;

                /*
                 * Artificially bump the refcount to ensure that the channel
                 * is only closed on exit.
                 *
                 * NOTE: Must only do this if stderrChannel is not NULL. It
                 * can be NULL in situations where Tcl is unable to connect
                 * to the standard error.
                 */

                if (stderrChannel != (Tcl_Channel) NULL) {
                    (void) Tcl_RegisterChannel((Tcl_Interp *) NULL,
                            stderrChannel);
                }
	    }
	    channel = stderrChannel;
	    break;
    }
    return channel;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_CreateCloseHandler
 *
 *	Creates a close callback which will be called when the channel is
 *	closed.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Causes the callback to be called in the future when the channel
 *	will be closed.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_CreateCloseHandler(chan, proc, clientData)
    Tcl_Channel chan;		/* The channel for which to create the
                                 * close callback. */
    Tcl_CloseProc *proc;	/* The callback routine to call when the
                                 * channel will be closed. */
    ClientData clientData;	/* Arbitrary data to pass to the
                                 * close callback. */
{
    Channel *chanPtr;
    CloseCallback *cbPtr;

    chanPtr = (Channel *) chan;

    cbPtr = (CloseCallback *) ckalloc((unsigned) sizeof(CloseCallback));
    cbPtr->proc = proc;
    cbPtr->clientData = clientData;

    cbPtr->nextPtr = chanPtr->closeCbPtr;
    chanPtr->closeCbPtr = cbPtr;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_DeleteCloseHandler --
 *
 *	Removes a callback that would have been called on closing
 *	the channel. If there is no matching callback then this
 *	function has no effect.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The callback will not be called in the future when the channel
 *	is eventually closed.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_DeleteCloseHandler(chan, proc, clientData)
    Tcl_Channel chan;		/* The channel for which to cancel the
                                 * close callback. */
    Tcl_CloseProc *proc;	/* The procedure for the callback to
                                 * remove. */
    ClientData clientData;	/* The callback data for the callback
                                 * to remove. */
{
    Channel *chanPtr;
    CloseCallback *cbPtr, *cbPrevPtr;

    chanPtr = (Channel *) chan;
    for (cbPtr = chanPtr->closeCbPtr, cbPrevPtr = (CloseCallback *) NULL;
             cbPtr != (CloseCallback *) NULL;
             cbPtr = cbPtr->nextPtr) {
        if ((cbPtr->proc == proc) && (cbPtr->clientData == clientData)) {
            if (cbPrevPtr == (CloseCallback *) NULL) {
                chanPtr->closeCbPtr = cbPtr->nextPtr;
            }
            ckfree((char *) cbPtr);
            break;
        } else {
            cbPrevPtr = cbPtr;
        }
    }
}

/*
 *----------------------------------------------------------------------
 *
 * CloseChannelsOnExit --
 *
 *	Closes all the existing channels, on exit. This	routine is called
 *	during exit processing.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Closes all channels.
 *
 *----------------------------------------------------------------------
 */

	/* ARGSUSED */
static void
CloseChannelsOnExit(clientData)
    ClientData clientData;		/* NULL - unused. */
{
    Channel *chanPtr;			/* Iterates over open channels. */
    Channel *nextChanPtr;		/* Iterates over open channels. */


    for (chanPtr = firstChanPtr; chanPtr != (Channel *) NULL;
             chanPtr = nextChanPtr) {
        nextChanPtr = chanPtr->nextChanPtr;

        /*
         * Set the channel back into blocking mode to ensure that we wait
         * for all data to flush out.
         */
        
        (void) Tcl_SetChannelOption(NULL, (Tcl_Channel) chanPtr,
                "-blocking", "on");

        if ((chanPtr == (Channel *) stdinChannel) ||
                (chanPtr == (Channel *) stdoutChannel) ||
                (chanPtr == (Channel *) stderrChannel)) {

            /*
             * Decrement the refcount which was earlier artificially bumped
             * up to keep the channel from being closed.
             */

            chanPtr->refCount--;
        }

        if (chanPtr->refCount <= 0) {

	    /*
             * Close it only if the refcount indicates that the channel is not
             * referenced from any interpreter. If it is, that interpreter will
             * close the channel when it gets destroyed.
             */

            (void) Tcl_Close((Tcl_Interp *) NULL, (Tcl_Channel) chanPtr);

        } else {

            /*
             * The refcount is greater than zero, so flush the channel.
             */

            Tcl_Flush((Tcl_Channel) chanPtr);

            /*
             * Call the device driver to actually close the underlying
             * device for this channel.
             */
            
            (chanPtr->typePtr->closeProc) (chanPtr->instanceData,
                    (Tcl_Interp *) NULL);

            /*
             * Finally, we clean up the fields in the channel data structure
             * since all of them have been deleted already. We mark the
             * channel with CHANNEL_DEAD to prevent any further IO operations
             * on it.
             */

            chanPtr->instanceData = (ClientData) NULL;
            chanPtr->flags |= CHANNEL_DEAD;
        }
    }

    /*
     * Reinitialize all the variables to the initial state:
     */
    
    firstChanPtr = (Channel *) NULL;
    nestedHandlerPtr = (NextChannelHandler *) NULL;
    channelExitHandlerCreated = 0;
    stdinChannel = NULL;
    stdinInitialized = 0;
    stdoutChannel = NULL;
    stdoutInitialized = 0;
    stderrChannel = NULL;
    stderrInitialized = 0;
}

/*
 *----------------------------------------------------------------------
 *
 * GetChannelTable --
 *
 *	Gets and potentially initializes the channel table for an
 *	interpreter. If it is initializing the table it also inserts
 *	channels for stdin, stdout and stderr if the interpreter is
 *	trusted.
 *
 * Results:
 *	A pointer to the hash table created, for use by the caller.
 *
 * Side effects:
 *	Initializes the channel table for an interpreter. May create
 *	channels for stdin, stdout and stderr.
 *
 *----------------------------------------------------------------------
 */

static Tcl_HashTable *
GetChannelTable(interp)
    Tcl_Interp *interp;
{
    Tcl_HashTable *hTblPtr;	/* Hash table of channels. */
    Tcl_Channel stdinChan, stdoutChan, stderrChan;

    hTblPtr = (Tcl_HashTable *) Tcl_GetAssocData(interp, "tclIO", NULL);
    if (hTblPtr == (Tcl_HashTable *) NULL) {
        hTblPtr = (Tcl_HashTable *) ckalloc((unsigned) sizeof(Tcl_HashTable));
        Tcl_InitHashTable(hTblPtr, TCL_STRING_KEYS);

        (void) Tcl_SetAssocData(interp, "tclIO",
                (Tcl_InterpDeleteProc *) DeleteChannelTable,
                (ClientData) hTblPtr);

        /*
         * If the interpreter is trusted (not "safe"), insert channels
         * for stdin, stdout and stderr (possibly creating them in the
         * process).
         */

        if (Tcl_IsSafe(interp) == 0) {
            stdinChan = Tcl_GetStdChannel(TCL_STDIN);
            if (stdinChan != NULL) {
                Tcl_RegisterChannel(interp, stdinChan);
            }
            stdoutChan = Tcl_GetStdChannel(TCL_STDOUT);
            if (stdoutChan != NULL) {
                Tcl_RegisterChannel(interp, stdoutChan);
            }
            stderrChan = Tcl_GetStdChannel(TCL_STDERR);
            if (stderrChan != NULL) {
                Tcl_RegisterChannel(interp, stderrChan);
            }
        }

    }
    return hTblPtr;
}

/*
 *----------------------------------------------------------------------
 *
 * DeleteChannelTable --
 *
 *	Deletes the channel table for an interpreter, closing any open
 *	channels whose refcount reaches zero. This procedure is invoked
 *	when an interpreter is deleted, via the AssocData cleanup
 *	mechanism.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Deletes the hash table of channels. May close channels. May flush