tcliogt.c

来自「tcl是工具命令语言」· C语言 代码 · 共 1,454 行 · 第 1/3 页

	return (*parentWideSeekProc) (parentData, offset, mode, errorCodePtr);
    }

    /*
     * We're transferring to narrow seeks at this point; this is a bit
     * complex because we have to check whether the seek is possible
     * first (i.e. whether we are losing information in truncating the
     * bits of the offset.)  Luckily, there's a defined error for what
     * happens when trying to go out of the representable range.
     */
    if (offset<Tcl_LongAsWide(LONG_MIN) || offset>Tcl_LongAsWide(LONG_MAX)) {
	*errorCodePtr = EOVERFLOW;
	return Tcl_LongAsWide(-1);
    }
    return Tcl_LongAsWide((*parentSeekProc) (parentData,
	    Tcl_WideAsLong(offset), mode, errorCodePtr));
}

/*
 *------------------------------------------------------*
 *
 *	TransformSetOptionProc --
 *
 *	Called by generic layer to handle the reconfi-
 *	guration of channel specific options. As this
 *	channel type does not have such, it simply passes
 *	all requests downstream.
 *
 *	Sideeffects:
 *		As defined by the channel downstream.
 *
 *	Result:
 *		A standard TCL error code.
 *
 *------------------------------------------------------*
 */

static int
TransformSetOptionProc (instanceData, interp, optionName, value)
    ClientData instanceData;
    Tcl_Interp *interp;
    CONST char *optionName;
    CONST char *value;
{
    TransformChannelData* dataPtr = (TransformChannelData*) instanceData;
    Tcl_Channel downChan = Tcl_GetStackedChannel(dataPtr->self);
    Tcl_DriverSetOptionProc *setOptionProc;

    setOptionProc = Tcl_ChannelSetOptionProc(Tcl_GetChannelType(downChan));
    if (setOptionProc != NULL) {
	return (*setOptionProc)(Tcl_GetChannelInstanceData(downChan),
		interp, optionName, value);
    }
    return TCL_ERROR;
}

/*
 *------------------------------------------------------*
 *
 *	TransformGetOptionProc --
 *
 *	Called by generic layer to handle requests for
 *	the values of channel specific options. As this
 *	channel type does not have such, it simply passes
 *	all requests downstream.
 *
 *	Sideeffects:
 *		As defined by the channel downstream.
 *
 *	Result:
 *		A standard TCL error code.
 *
 *------------------------------------------------------*
 */

static int
TransformGetOptionProc (instanceData, interp, optionName, dsPtr)
    ClientData   instanceData;
    Tcl_Interp*  interp;
    CONST char*        optionName;
    Tcl_DString* dsPtr;
{
    TransformChannelData* dataPtr = (TransformChannelData*) instanceData;
    Tcl_Channel downChan = Tcl_GetStackedChannel(dataPtr->self);
    Tcl_DriverGetOptionProc *getOptionProc;

    getOptionProc = Tcl_ChannelGetOptionProc(Tcl_GetChannelType(downChan));
    if (getOptionProc != NULL) {
	return (*getOptionProc)(Tcl_GetChannelInstanceData(downChan),
		interp, optionName, dsPtr);
    } else if (optionName == (CONST char*) NULL) {
	/*
	 * Request is query for all options, this is ok.
	 */
	return TCL_OK;
    }
    /*
     * Request for a specific option has to fail, we don't have any.
     */
    return TCL_ERROR;
}

/*
 *------------------------------------------------------*
 *
 *	TransformWatchProc --
 *
 *	Initialize the notifier to watch for events from
 *	this channel.
 *
 *	Sideeffects:
 *		Sets up the notifier so that a future
 *		event on the channel will be seen by Tcl.
 *
 *	Result:
 *		None.
 *
 *------------------------------------------------------*
 */
	/* ARGSUSED */
static void
TransformWatchProc (instanceData, mask)
    ClientData instanceData;	/* Channel to watch */
    int        mask;		/* Events of interest */
{
    /* The caller expressed interest in events occuring for this
     * channel. We are forwarding the call to the underlying
     * channel now.
     */

    TransformChannelData* dataPtr = (TransformChannelData*) instanceData;
    Tcl_Channel     downChan;

    dataPtr->watchMask = mask;

    /* No channel handlers any more. We will be notified automatically
     * about events on the channel below via a call to our
     * 'TransformNotifyProc'. But we have to pass the interest down now.
     * We are allowed to add additional 'interest' to the mask if we want
     * to. But this transformation has no such interest. It just passes
     * the request down, unchanged.
     */

    downChan = Tcl_GetStackedChannel(dataPtr->self);

    (Tcl_GetChannelType(downChan))
	->watchProc(Tcl_GetChannelInstanceData(downChan), mask);

    /*
     * Management of the internal timer.
     */

    if ((dataPtr->timer != (Tcl_TimerToken) NULL) &&
	    (!(mask & TCL_READABLE) || (ResultLength(&dataPtr->result) == 0))) {

        /* A pending timer exists, but either is there no (more)
	 * interest in the events it generates or nothing is availablee
	 * for reading, so remove it.
	 */

        Tcl_DeleteTimerHandler (dataPtr->timer);
	dataPtr->timer = (Tcl_TimerToken) NULL;
    }

    if ((dataPtr->timer == (Tcl_TimerToken) NULL) &&
	    (mask & TCL_READABLE) && (ResultLength (&dataPtr->result) > 0)) {

        /* There is no pending timer, but there is interest in readable
	 * events and we actually have data waiting, so generate a timer
	 * to flush that.
	 */

	dataPtr->timer = Tcl_CreateTimerHandler (FLUSH_DELAY,
		TransformChannelHandlerTimer, (ClientData) dataPtr);
    }
}

/*
 *------------------------------------------------------*
 *
 *	TransformGetFileHandleProc --
 *
 *	Called from Tcl_GetChannelHandle to retrieve
 *	OS specific file handle from inside this channel.
 *
 *	Sideeffects:
 *		None.
 *
 *	Result:
 *		The appropriate Tcl_File or NULL if not
 *		present. 
 *
 *------------------------------------------------------*
 */
static int
TransformGetFileHandleProc (instanceData, direction, handlePtr)
    ClientData  instanceData;	/* Channel to query */
    int         direction;	/* Direction of interest */
    ClientData* handlePtr;	/* Place to store the handle into */
{
    /*
     * Return the handle belonging to parent channel.
     * IOW, pass the request down and the result up.
     */

    TransformChannelData* dataPtr = (TransformChannelData*) instanceData;

    return Tcl_GetChannelHandle(Tcl_GetStackedChannel(dataPtr->self),
	    direction, handlePtr);
}

/*
 *------------------------------------------------------*
 *
 *	TransformNotifyProc --
 *
 *	------------------------------------------------*
 *	Handler called by Tcl to inform us of activity
 *	on the underlying channel.
 *	------------------------------------------------*
 *
 *	Sideeffects:
 *		May process the incoming event by itself.
 *
 *	Result:
 *		None.
 *
 *------------------------------------------------------*
 */

static int
TransformNotifyProc (clientData, mask)
    ClientData	   clientData; /* The state of the notified transformation */
    int		   mask;       /* The mask of occuring events */
{
    TransformChannelData* dataPtr = (TransformChannelData*) clientData;

    /*
     * An event occured in the underlying channel.  This
     * transformation doesn't process such events thus returns the
     * incoming mask unchanged.
     */

    if (dataPtr->timer != (Tcl_TimerToken) NULL) {
	/*
	 * Delete an existing timer. It was not fired, yet we are
	 * here, so the channel below generated such an event and we
	 * don't have to. The renewal of the interest after the
	 * execution of channel handlers will eventually cause us to
	 * recreate the timer (in TransformWatchProc).
	 */

	Tcl_DeleteTimerHandler (dataPtr->timer);
	dataPtr->timer = (Tcl_TimerToken) NULL;
    }

    return mask;
}

/*
 *------------------------------------------------------*
 *
 *	TransformChannelHandlerTimer --
 *
 *	Called by the notifier (-> timer) to flush out
 *	information waiting in the input buffer.
 *
 *	Sideeffects:
 *		As of 'Tcl_NotifyChannel'.
 *
 *	Result:
 *		None.
 *
 *------------------------------------------------------*
 */

static void
TransformChannelHandlerTimer (clientData)
    ClientData clientData; /* Transformation to query */
{
    TransformChannelData* dataPtr = (TransformChannelData*) clientData;

    dataPtr->timer = (Tcl_TimerToken) NULL;

    if (!(dataPtr->watchMask & TCL_READABLE) ||
	    (ResultLength (&dataPtr->result) == 0)) {
	/* The timer fired, but either is there no (more)
	 * interest in the events it generates or nothing is available
	 * for reading, so ignore it and don't recreate it.
	 */

	return;
    }

    Tcl_NotifyChannel(dataPtr->self, TCL_READABLE);
}

/*
 *------------------------------------------------------*
 *
 *	ResultClear --
 *
 *	Deallocates any memory allocated by 'ResultAdd'.
 *
 *	Sideeffects:
 *		See above.
 *
 *	Result:
 *		None.
 *
 *------------------------------------------------------*
 */

static void
ResultClear (r)
    ResultBuffer* r; /* Reference to the buffer to clear out */
{
    r->used = 0;

    if (r->allocated) {
        ckfree((char*) r->buf);
	r->buf       = UCHARP (NULL);
	r->allocated = 0;
    }
}

/*
 *------------------------------------------------------*
 *
 *	ResultInit --
 *
 *	Initializes the specified buffer structure. The
 *	structure will contain valid information for an
 *	emtpy buffer.
 *
 *	Sideeffects:
 *		See above.
 *
 *	Result:
 *		None.
 *
 *------------------------------------------------------*
 */

static void
ResultInit (r)
    ResultBuffer* r; /* Reference to the structure to initialize */
{
    r->used      = 0;
    r->allocated = 0;
    r->buf       = UCHARP (NULL);
}

/*
 *------------------------------------------------------*
 *
 *	ResultLength --
 *
 *	Returns the number of bytes stored in the buffer.
 *
 *	Sideeffects:
 *		None.
 *
 *	Result:
 *		An integer, see above too.
 *
 *------------------------------------------------------*
 */

static int
ResultLength (r)
    ResultBuffer* r; /* The structure to query */
{
    return r->used;
}

/*
 *------------------------------------------------------*
 *
 *	ResultCopy --
 *
 *	Copies the requested number of bytes from the
 *	buffer into the specified array and removes them
 *	from the buffer afterward. Copies less if there
 *	is not enough data in the buffer.
 *
 *	Sideeffects:
 *		See above.
 *
 *	Result:
 *		The number of actually copied bytes,
 *		possibly less than 'toRead'.
 *
 *------------------------------------------------------*
 */

static int
ResultCopy (r, buf, toRead)
    ResultBuffer*  r;      /* The buffer to read from */
    unsigned char* buf;    /* The buffer to copy into */
    int		   toRead; /* Number of requested bytes */
{
    if (r->used == 0) {
        /* Nothing to copy in the case of an empty buffer.
	 */

        return 0;
    }

    if (r->used == toRead) {
        /* We have just enough. Copy everything to the caller.
	 */

        memcpy ((VOID*) buf, (VOID*) r->buf, (size_t) toRead);
	r->used = 0;
	return toRead;
    }

    if (r->used > toRead) {
        /* The internal buffer contains more than requested.
	 * Copy the requested subset to the caller, and shift
	 * the remaining bytes down.
	 */

        memcpy  ((VOID*) buf,    (VOID*) r->buf,            (size_t) toRead);
	memmove ((VOID*) r->buf, (VOID*) (r->buf + toRead),
		(size_t) r->used - toRead);

	r->used -= toRead;
	return toRead;
    }

    /* There is not enough in the buffer to satisfy the caller, so
     * take everything.
     */

    memcpy((VOID*) buf, (VOID*) r->buf, (size_t) r->used);
    toRead  = r->used;
    r->used = 0;
    return toRead;
}

/*
 *------------------------------------------------------*
 *
 *	ResultAdd --
 *
 *	Adds the bytes in the specified array to the
 *	buffer, by appending it.
 *
 *	Sideeffects:
 *		See above.
 *
 *	Result:
 *		None.
 *
 *------------------------------------------------------*
 */

static void
ResultAdd (r, buf, toWrite)
    ResultBuffer*  r;       /* The buffer to extend */
    unsigned char* buf;     /* The buffer to read from */
    int		   toWrite; /* The number of bytes in 'buf' */
{
    if ((r->used + toWrite) > r->allocated) {
        /* Extension of the internal buffer is required.
	 */

        if (r->allocated == 0) {
	    r->allocated = toWrite + INCREMENT;
	    r->buf       = UCHARP (ckalloc((unsigned) r->allocated));
	} else {
	    r->allocated += toWrite + INCREMENT;
	    r->buf        = UCHARP (ckrealloc((char*) r->buf,
		    (unsigned) r->allocated));
	}
    }

    /* now copy data */
    memcpy(r->buf + r->used, buf, (size_t) toWrite);
    r->used += toWrite;
}