connectors/jk/native/common/jk_sockbuf.c

/*
 *  Copyright 1999-2004 The Apache Software Foundation
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

/***************************************************************************
 * Description: Simple buffer object to handle buffered socket IO          *
 * Author:      Gal Shachor <shachor@il.ibm.com>                           *
 * Version:     $Revision$                                           *
 ***************************************************************************/

#include "jk_global.h"
#include "jk_sockbuf.h"

static int fill_buffer(jk_sockbuf_t *sb);

int jk_sb_open(jk_sockbuf_t *sb,
               int sd)
{
    if(sb && sd >= 0) {
        sb->end   = 0;
        sb->start = 0;
        sb->sd    = sd;
        return JK_TRUE;
    }

    return JK_FALSE;
}

int jk_sb_write(jk_sockbuf_t *sb,
                const void *buf, 
                unsigned sz)
{
    if(sb && buf && sz) {
        if((SOCKBUF_SIZE - sb->end) >= sz) {
            memcpy(sb->buf + sb->end, buf, sz);
            sb->end += sz;
        } else {
            if(!jk_sb_flush(sb)) {
                return JK_FALSE;
            }
            if(sz > SOCKBUF_SIZE) {
                return (send(sb->sd, (char *)buf, sz, 0) == (int)sz);
            } 
            
            memcpy(sb->buf + sb->end, buf, sz);
            sb->end += sz;
        }

        return JK_TRUE;
    }

    return JK_FALSE;
}

int jk_sb_flush(jk_sockbuf_t *sb)
{
    if(sb) {
        int save_out = sb->end;
        sb->end = sb->start = 0;
        if(save_out) {            
            return send(sb->sd, sb->buf, save_out, 0) == save_out;
        }
        return JK_TRUE;
    }

    return JK_FALSE;
}


int jk_sb_read(jk_sockbuf_t *sb,
               char **buf, 
               unsigned sz,
               unsigned *ac)
{
    if(sb && buf && ac) {
        unsigned avail;

        *ac = 0;
        *buf = NULL;

        if(sb->end == sb->start) {
            sb->end = sb->start = 0;
            if(fill_buffer(sb) < 0) {
                return JK_FALSE;
            }
        }
        
        *buf = sb->buf + sb->start;
        avail = sb->end - sb->start;
        if(avail > sz) {
            *ac = sz;
        } else {
            *ac = avail;
        }
        sb->start += *ac;

        return JK_TRUE;
    }

    return JK_FALSE;
}

int jk_sb_gets(jk_sockbuf_t *sb,
               char **ps)
{
    int ret;
    if(sb) {
        while(1) {
            unsigned i;
            for(i = sb->start ; i < sb->end ; i++) {
                if(JK_LF == sb->buf[i]) {
                    if(i > sb->start && JK_CR == sb->buf[i - 1]) {
                        sb->buf[i - 1] = '\0';
                    } else {
                        sb->buf[i] = '\0';
                    }
                    *ps = sb->buf + sb->start;
                    sb->start = (i + 1);
                    return JK_TRUE;
                }
            }
            if((ret = fill_buffer(sb)) < 0) {
                return JK_FALSE;
            } else if (ret == 0) {
                *ps = sb->buf + sb->start;
               if ((SOCKBUF_SIZE - sb->end) > 0) {
                    sb->buf[sb->end] = '\0';
                } else {
                    sb->buf[sb->end-1] = '\0';
                }
                return JK_TRUE;
            }
        }
    }

    return JK_FALSE;
}

/*
 * Read data from the socket into the associated buffer, and update the
 * start and end indices.  May move the data currently in the buffer.  If
 * new data is read into the buffer (or if it is already full), returns 1.
 * If EOF is received on the socket, returns 0.  In case of error returns
 * -1.  
 */
static int fill_buffer(jk_sockbuf_t *sb)
{
    int ret;
    
    /*
     * First move the current data to the beginning of the buffer
     */
    if(sb->start < sb->end) {
        if(sb->start > 0) {
            unsigned to_copy = sb->end - sb->start;
            memmove(sb->buf, sb->buf + sb->start, to_copy);
            sb->start = 0;
            sb->end = to_copy;
        }
    } else {
        sb->start = sb->end = 0;
    }
    
    /*
     * In the unlikely case where the buffer is already full, we won't be
     * reading anything and we'd be calling recv with a 0 count.  
     */
    if ((SOCKBUF_SIZE - sb->end) > 0) {
	/*
	 * Now, read more data
	 */
	ret = recv(sb->sd, 
		   sb->buf + sb->end, 
		   SOCKBUF_SIZE - sb->end, 0);   
	
	/* 0 is EOF/SHUTDOWN, -1 is SOCK_ERROR */
	if (ret <= 0) {
	    return ret;
	} 
	
	sb->end += ret;
    }
    
    return 1;
}