io.c

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#endif
	    client->req_len = needed;
	    needed <<= 2;
	}
	if (gotnow < needed)
	{
	    /* Still don't have enough; punt. */
	    YieldControlNoInput();
	    return 0;
	}
    }
    if (needed == 0)
    {
#ifdef BIGREQS
	if (client->big_requests)
	    needed = sizeof(xBigReq);
	else
#endif
	    needed = sizeof(xReq);
    }
    oci->lenLastReq = needed;

    /*
     *  Check to see if client has at least one whole request in the
     *  buffer beyond the request we're returning to the caller.
     *  If there is only a partial request, treat like buffer
     *  is empty so that select() will be called again and other clients
     *  can get into the queue.   
     */

    gotnow -= needed;
    if (gotnow >= sizeof(xReq)) 
    {
	request = (xReq *)(oci->bufptr + needed);
	if (gotnow >= (result = (get_req_len(request, client) << 2))
#ifdef BIGREQS
	    && (result ||
		(client->big_requests &&
		 (gotnow >= sizeof(xBigReq) &&
		  gotnow >= (get_big_req_len(request, client) << 2))))
#endif
	    )
	    FD_SET(fd, &ClientsWithInput);
	else
	    YieldControlNoInput();
    }
    else
    {
	if (!gotnow)
	    AvailableInput = oc;
	YieldControlNoInput();
    }
    if (++timesThisConnection >= MAX_TIMES_PER)
	YieldControl();
#ifdef BIGREQS
    if (move_header)
    {
	request = (xReq *)oci->bufptr;
	oci->bufptr += (sizeof(xBigReq) - sizeof(xReq));
	*(xReq *)oci->bufptr = *request;
	oci->lenLastReq -= (sizeof(xBigReq) - sizeof(xReq));
	client->req_len -= (sizeof(xBigReq) - sizeof(xReq)) >> 2;
    }
#endif
    client->requestBuffer = (pointer)oci->bufptr;
    return needed;
}

/*****************************************************************
 * InsertFakeRequest
 *    Splice a consed up (possibly partial) request in as the next request.
 *
 **********************/

Bool
InsertFakeRequest(client, data, count)
    ClientPtr client;
    char *data;
    int count;
{
    OsCommPtr oc = (OsCommPtr)client->osPrivate;
    register ConnectionInputPtr oci = oc->input;
    int fd = oc->fd;
    register int gotnow, moveup;

    if (AvailableInput)
    {
	if (AvailableInput != oc)
	{
	    register ConnectionInputPtr aci = AvailableInput->input;
	    if (aci->size > BUFWATERMARK)
	    {
		xfree(aci->buffer);
		xfree(aci);
	    }
	    else
	    {
		aci->next = FreeInputs;
		FreeInputs = aci;
	    }
	    AvailableInput->input = (ConnectionInputPtr)NULL;
	}
	AvailableInput = (OsCommPtr)NULL;
    }
    if (!oci)
    {
	if (oci = FreeInputs)
	    FreeInputs = oci->next;
	else if (!(oci = AllocateInputBuffer()))
	    return FALSE;
	oc->input = oci;
    }
    oci->bufptr += oci->lenLastReq;
    oci->lenLastReq = 0;
    gotnow = oci->bufcnt + oci->buffer - oci->bufptr;
    if ((gotnow + count) > oci->size)
    {
	char *ibuf;

	ibuf = (char *)xrealloc(oci->buffer, gotnow + count);
	if (!ibuf)
	    return(FALSE);
	oci->size = gotnow + count;
	oci->buffer = ibuf;
	oci->bufptr = ibuf + oci->bufcnt - gotnow;
    }
    moveup = count - (oci->bufptr - oci->buffer);
    if (moveup > 0)
    {
	if (gotnow > 0)
	    memmove(oci->bufptr + moveup, oci->bufptr, gotnow);
	oci->bufptr += moveup;
	oci->bufcnt += moveup;
    }
    memmove(oci->bufptr - count, data, count);
    oci->bufptr -= count;
    gotnow += count;
    if ((gotnow >= sizeof(xReq)) &&
	(gotnow >= (int)(get_req_len((xReq *)oci->bufptr, client) << 2)))
	FD_SET(fd, &ClientsWithInput);
    else
	YieldControlNoInput();
    return(TRUE);
}

/*****************************************************************
 * ResetRequestFromClient
 *    Reset to reexecute the current request, and yield.
 *
 **********************/

ResetCurrentRequest(client)
    ClientPtr client;
{
    OsCommPtr oc = (OsCommPtr)client->osPrivate;
    register ConnectionInputPtr oci = oc->input;
    int fd = oc->fd;
    register xReq *request;
    int gotnow, needed;
#ifdef LBX
    Bool part;
    LbxClientPtr lbxClient = LbxClient(client);

    if (lbxClient) {
	LbxSetForBlock(lbxClient);
	if (!oci) {
	    AppendFakeRequest(client,
			      client->requestBuffer, client->req_len << 2);
	    return;
	}
    }
#endif
    if (AvailableInput == oc)
	AvailableInput = (OsCommPtr)NULL;
    oci->lenLastReq = 0;
    gotnow = oci->bufcnt + oci->buffer - oci->bufptr;
    if (gotnow < sizeof(xReq))
    {
	YieldControlNoInput();
    }
    else
    {
	request = (xReq *)oci->bufptr;
	needed = get_req_len(request, client);
#ifdef BIGREQS
	if (!needed && client->big_requests)
	{
	    oci->bufptr -= sizeof(xBigReq) - sizeof(xReq);
	    *(xReq *)oci->bufptr = *request;
	    ((xBigReq *)oci->bufptr)->length = client->req_len;
	    if (client->swapped)
	    {
		char n;
		swapl(&((xBigReq *)oci->bufptr)->length, n);
	    }
	}
#endif
	if (gotnow >= (needed << 2))
	{
	    if (FD_ISSET(fd, &AllClients))
	    {
		FD_SET(fd, &ClientsWithInput);
	    }
	    else
	    {
		FD_SET(fd, &IgnoredClientsWithInput);
	    }
	    YieldControl();
	}
	else
	    YieldControlNoInput();
    }
}



/*****************************************************************
 *  PeekNextRequest and SkipRequests were implemented to support DBE 
 *  idioms, but can certainly be used outside of DBE.  There are two 
 *  related macros in os.h, ReqLen and CastxReq.  See the porting 
 *  layer document for more details.
 *
 **********************/


/*****************************************************************
 *  PeekNextRequest
 *      lets you look ahead at the unexecuted requests in a 
 *      client's request buffer.
 *
 *      Note: this implementation of PeekNextRequest ignores the
 *      readmore parameter.
 *
 **********************/

xReqPtr
PeekNextRequest(req, client, readmore)
    xReqPtr req;	/* request we're starting from */
    ClientPtr client;	/* client whose requests we're skipping */
    Bool readmore;	/* attempt to read more if next request isn't there? */
{
    register ConnectionInputPtr oci = ((OsCommPtr)client->osPrivate)->input;
    xReqPtr pnextreq;
    int needed, gotnow, reqlen;

    if (!oci) return NULL;

    if (!req)
    {
	/* caller wants the request after the one currently being executed */
	pnextreq = (xReqPtr)
	    (((CARD32 *)client->requestBuffer) + client->req_len);
    }
    else
    {
	/* caller wants the request after the one specified by req */
	reqlen = get_req_len(req, client);
#ifdef BIGREQS
	if (!reqlen) reqlen = get_big_req_len(req, client);
#endif
	pnextreq = (xReqPtr)(((char *)req) + (reqlen << 2));
    }

    /* see how much of the next request we have available */

    gotnow = oci->bufcnt - (((char *)pnextreq) - oci->buffer);

    if (gotnow < sizeof(xReq))
	return NULL;

    needed = get_req_len(pnextreq, client) << 2;
#ifdef BIGREQS
    if (!needed)
    {
	/* it's a big request */
	if (gotnow < sizeof(xBigReq))
	    return NULL;
	needed = get_big_req_len(pnextreq, client) << 2;
    }
#endif

    /* if we have less than we need, return NULL */

    return (gotnow < needed) ? NULL : pnextreq;
}

/*****************************************************************
 *  SkipRequests 
 *      lets you skip over some of the requests in a client's
 *      request buffer.  Presumably the caller has used PeekNextRequest
 *      to examine the requests being skipped and has performed whatever 
 *      actions they dictate.
 *
 **********************/

CallbackListPtr SkippedRequestsCallback = NULL;

void
SkipRequests(req, client, numskipped)
    xReqPtr req;	/* last request being skipped */
    ClientPtr client;   /* client whose requests we're skipping */
    int numskipped;	/* how many requests we're skipping */
{
    OsCommPtr oc = (OsCommPtr)client->osPrivate;
    register ConnectionInputPtr oci = oc->input;
    int reqlen;

    /* see if anyone wants to snoop the skipped requests */

    if (SkippedRequestsCallback)
    {
	SkippedRequestInfoRec skipinfo;
	skipinfo.req = req;
	skipinfo.client = client;
	skipinfo.numskipped = numskipped;
	CallCallbacks(&SkippedRequestsCallback, &skipinfo);
    }

    /* adjust the sequence number */
    client->sequence += numskipped;

    /* twiddle the oci to skip over the requests */

    reqlen = get_req_len(req, client);
#ifdef BIGREQS
    if (!reqlen) reqlen = get_big_req_len(req, client);
#endif
    reqlen <<= 2;
    oci->bufptr = (char *)req;
    oci->lenLastReq = reqlen;

    /* see if any requests left in the buffer */

    if ( ((char *)req + reqlen) == (oci->buffer + oci->bufcnt) )
    {
	/* no requests; mark input buffer as available and client
	 * as having no input
	 */
	int fd = oc->fd;
	AvailableInput = oc;
	YieldControlNoInput();
    }
}


    /* lookup table for adding padding bytes to data that is read from
    	or written to the X socket.  */
static int padlength[4] = {0, 3, 2, 1};

 /********************
 * FlushClient()
 *    If the client isn't keeping up with us, then we try to continue
 *    buffering the data and set the apropriate bit in ClientsWritable
 *    (which is used by WaitFor in the select).  If the connection yields
 *    a permanent error, or we can't allocate any more space, we then
 *    close the connection.
 *
 **********************/

int
#ifdef LBX
StandardFlushClient(who, oc, extraBuf, extraCount)
#else
FlushClient(who, oc, extraBuf, extraCount)
#endif
    ClientPtr who;
    OsCommPtr oc;
    char *extraBuf;
    int extraCount; /* do not modify... returned below */
{
    register ConnectionOutputPtr oco = oc->output;
    int connection = oc->fd;
    XtransConnInfo trans_conn = oc->trans_conn;
    struct iovec iov[3];
    static char padBuffer[3];
    long written;
    long padsize;
    long notWritten;
    long todo;

    if (!oco)
	return 0;
    written = 0;
    padsize = padlength[extraCount & 3];
    notWritten = oco->count + extraCount + padsize;
    todo = notWritten;
    while (notWritten) {
	long before = written;	/* amount of whole thing written */
	long remain = todo;	/* amount to try this time, <= notWritten */
	int i = 0;
	long len;

	/* You could be very general here and have "in" and "out" iovecs
	 * and write a loop without using a macro, but what the heck.  This
	 * translates to:
	 *
	 *     how much of this piece is new?
	 *     if more new then we are trying this time, clamp
	 *     if nothing new
	 *         then bump down amount already written, for next piece
	 *         else put new stuff in iovec, will need all of next piece
	 *
	 * Note that todo had better be at least 1 or else we'll end up
	 * writing 0 iovecs.
	 */
#define InsertIOV(pointer, length) \
	len = (length) - before; \
	if (len > remain) \
	    len = remain; \
	if (len <= 0) { \
	    before = (-len); \
	} else { \
	    iov[i].iov_len = len; \
	    iov[i].iov_base = (pointer) + before; \
	    i++; \
	    remain -= len; \
	    before = 0; \
	}

	InsertIOV ((char *)oco->buf, oco->count)
	InsertIOV (extraBuf, extraCount)