/*
 * The contents of this file are subject to the AOLserver Public License
 * Version 1.1 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://aolserver.lcs.mit.edu/.
 *
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 * the License for the specific language governing rights and limitations
 * under the License.
 *
 * Copyright (C) 2007 Tom Jackson
 * All rights reserved.
 *
 * Alternatively, the contents of this file may be used under the terms
 * of the GNU General Public License (the "GPL"), in which case the
 * provisions of GPL are applicable instead of those above.  If you wish
 * to allow use of your version of this file only under the terms of the
 * GPL and not to allow others to use your version of this file under the
 * License, indicate your decision by deleting the provisions above and
 * replace them with the notice and other provisions required by the GPL.
 * If you do not delete the provisions above, a recipient may use your
 * version of this file under either the License or the GPL.
 */

/*
 * nsbgwrite.c -- Enables removal of Sock from Conn wrapped in channel.
 *
 * Author
 *     Tom Jackson <tom@junom.com>
 *
 *     Based upon code written by Zoran Vasiljevic and 
 *     extended by Gustaf Neumann.
 *     Module template design take from nszlib by Vlad Seryakov.
 */

#include "nsbgwrite.h"

#define VERSION "4.5"

static Tcl_Channel MakeConnChannel(Ns_Conn *conn, int spliceout);
static int BgWriteObjCmd(ClientData ignored, Tcl_Interp *interp, int objc,
			Tcl_Obj * CONST objv[]);
static int BgTrace(Tcl_Interp *interp, void *ignored);


/*
 *----------------------------------------------------------------------
 *
 * Nsbgwrite_Init--
 *
 *      Tcl load-command entry point.
 *
 * Results:
 *      TCL_OK.
 *
 * Side effects:
 *	Adds the ns_bgwrite command.
 *
 *----------------------------------------------------------------------
 */

int
Nsbgwrite_Init(Tcl_Interp *interp)
{
    Tcl_CreateObjCommand(interp, "ns_bgwrite",BgWriteObjCmd ,NULL, NULL);
    return TCL_OK;
}


/*
 *----------------------------------------------------------------------
 *
 * NsBgWriteModInit--
 *
 *      AOLserver module entry point.
 *
 * Results:
 *      NS_OK.
 *
 * Side effects:
 *	Registers a trace to create ns_bgwrite command in all new
 *      interps.
 *
 *----------------------------------------------------------------------
 */

int
NsBgWriteModInit(char *server, char *module)
{
    Ns_TclRegisterTrace(server, BgTrace, NULL, NS_TCL_TRACE_CREATE);
    return NS_OK;
}


/*
 *----------------------------------------------------------------------
 *
 * BgWriteObjCmd --
 *
 *      Implements the ns_bgwrite command.
 *
 * Results:
 *      Standard Tcl result.
 *
 * Side effects:
 *      None.
 *
 *----------------------------------------------------------------------
 */

static
int BgWriteObjCmd(ClientData arg, Tcl_Interp *interp, int objc,
		Tcl_Obj * CONST objv[])
{
    Ns_Conn      *conn;
    Tcl_Channel   chan;
    Tcl_Obj	 *result;
    int           nContentSent;

    static CONST char *opts[] = {
      "channel", "contentsentlength",
	NULL
    };
    enum {
      CChannelIdx, CContentSentLenIdx
    } opt;

    if (objc < 2) {
	Tcl_WrongNumArgs(interp, 1, objv, "option ?arg?");
        return TCL_ERROR;
    }
    if (Tcl_GetIndexFromObj(interp, objv[1], opts, "option", 0,
			    (int *) &opt) != TCL_OK) 
    {
	return TCL_ERROR;
    }

    result = Tcl_GetObjResult(interp);
    conn = Ns_GetConn();

    if (conn == NULL) {
	Tcl_AppendResult(interp, "no current connection", NULL);
	return TCL_ERROR;
    }

    switch (opt) {
        
        case CChannelIdx:
      	    chan = MakeConnChannel(conn, 1);
	    if (chan == NULL) {
             Tcl_AppendResult(interp, Tcl_PosixError(interp), NULL);
              return TCL_ERROR;
	    }
	    Tcl_RegisterChannel(interp, chan);
	    Tcl_SetStringObj(result, Tcl_GetChannelName(chan), -1);
            break;

        case CContentSentLenIdx:
  	    if (objc == 2) {
	        Tcl_SetIntObj(result, Ns_ConnContentSent(conn));
	    } else if (objc == 3) {
	        if (Tcl_GetIntFromObj(interp, objv[2], &nContentSent) != TCL_OK
		    || Ns_ConnSetContentSent(conn, nContentSent) != TCL_OK) 
	        {
	            return TCL_ERROR;
	        }
	    
	    } else {
	        Tcl_WrongNumArgs(interp, 2, objv, "?value?");
	        return TCL_ERROR;
	    }
	    break;
     }

    return TCL_OK;

}


/*----------------------------------------------------------------------------
 * MakeConnChannel --
 *
 *      Wraps a Tcl channel around the current connection socket
 *      and returns the channel handle to the caller.
 *  
 * Result:
 *      Tcl_Channel handle or NULL.
 *
 * Side Effects:
 *      Flushes the connection socket before dup'ing.
 *      The resulting Tcl channel is set to blocking mode.
 *      On error, connection socket is restored.
 *
 *----------------------------------------------------------------------------
 */

static Tcl_Channel
MakeConnChannel(Ns_Conn *conn, int spliceout)
{
    Tcl_Channel chan;
    SOCKET      sock;
    
    /*
     * Assures the socket is flushed
     */

    Ns_WriteConn(conn, NULL, 0);

    /* 
     * spliceout is always 1, why?
     */

    if (spliceout) {
        sock = Ns_ConnSock(conn);
        if (Ns_ConnSetSockInvalid(conn) != NS_OK) {
	    return NULL;
        }
    } else {
        sock = ns_sockdup(Ns_ConnSock(conn));
    }

    if (sock == INVALID_SOCKET) {
        return NULL;
    }
    
    /*
     * At this point we may also set some other
     * chan config options (binary,encoding, etc)
     */

    Ns_SockSetBlocking(sock);

    /*
     * Wrap a Tcl TCP channel around the socket.
     */
    
    chan = Tcl_MakeTcpClientChannel((ClientData)sock);

    /*
     * Undo INVALID if unable to make channel,
     * otherwise close conn sock.
     * TJ: Note, spliceout is always 1, why?
     */

    if (chan == NULL && spliceout) {
        Ns_ConnSetSock(conn,sock);
    } else if (chan != NULL) {
        ns_sockclose(Ns_ConnSock(conn));
    }

    return chan;
}


/*
 *----------------------------------------------------------------------
 *
 * BgTrace --
 *
 *      AOLserver Tcl trace to add ns_bgwrite command.
 *
 * Results:
 *      NS_OK.
 *
 * Side effects:
 *      None.
 *
 *----------------------------------------------------------------------
 */

static int
BgTrace(Tcl_Interp *interp, void *ignored)
{
    Nsbgwrite_Init(interp);
    return NS_OK;
}