view src/core/ngx_buf.c @ 5742:c45c9812cf11

Core: removed meaningless check from ngx_palloc_block(). The check became meaningless after refactoring in 2a92804f4109. With the loop currently in place, "current" can't be NULL, hence the check can be dropped. Additionally, the local variable "current" was removed to simplify code, and pool->current now used directly instead. Found by Coverity (CID 714236).
author Maxim Dounin <mdounin@mdounin.ru>
date Thu, 26 Jun 2014 03:34:19 +0400
parents d620f497c50f
children f9c83484d9ce
line wrap: on
line source


/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#include <ngx_config.h>
#include <ngx_core.h>


ngx_buf_t *
ngx_create_temp_buf(ngx_pool_t *pool, size_t size)
{
    ngx_buf_t *b;

    b = ngx_calloc_buf(pool);
    if (b == NULL) {
        return NULL;
    }

    b->start = ngx_palloc(pool, size);
    if (b->start == NULL) {
        return NULL;
    }

    /*
     * set by ngx_calloc_buf():
     *
     *     b->file_pos = 0;
     *     b->file_last = 0;
     *     b->file = NULL;
     *     b->shadow = NULL;
     *     b->tag = 0;
     *     and flags
     */

    b->pos = b->start;
    b->last = b->start;
    b->end = b->last + size;
    b->temporary = 1;

    return b;
}


ngx_chain_t *
ngx_alloc_chain_link(ngx_pool_t *pool)
{
    ngx_chain_t  *cl;

    cl = pool->chain;

    if (cl) {
        pool->chain = cl->next;
        return cl;
    }

    cl = ngx_palloc(pool, sizeof(ngx_chain_t));
    if (cl == NULL) {
        return NULL;
    }

    return cl;
}


ngx_chain_t *
ngx_create_chain_of_bufs(ngx_pool_t *pool, ngx_bufs_t *bufs)
{
    u_char       *p;
    ngx_int_t     i;
    ngx_buf_t    *b;
    ngx_chain_t  *chain, *cl, **ll;

    p = ngx_palloc(pool, bufs->num * bufs->size);
    if (p == NULL) {
        return NULL;
    }

    ll = &chain;

    for (i = 0; i < bufs->num; i++) {

        b = ngx_calloc_buf(pool);
        if (b == NULL) {
            return NULL;
        }

        /*
         * set by ngx_calloc_buf():
         *
         *     b->file_pos = 0;
         *     b->file_last = 0;
         *     b->file = NULL;
         *     b->shadow = NULL;
         *     b->tag = 0;
         *     and flags
         *
         */

        b->pos = p;
        b->last = p;
        b->temporary = 1;

        b->start = p;
        p += bufs->size;
        b->end = p;

        cl = ngx_alloc_chain_link(pool);
        if (cl == NULL) {
            return NULL;
        }

        cl->buf = b;
        *ll = cl;
        ll = &cl->next;
    }

    *ll = NULL;

    return chain;
}


ngx_int_t
ngx_chain_add_copy(ngx_pool_t *pool, ngx_chain_t **chain, ngx_chain_t *in)
{
    ngx_chain_t  *cl, **ll;

    ll = chain;

    for (cl = *chain; cl; cl = cl->next) {
        ll = &cl->next;
    }

    while (in) {
        cl = ngx_alloc_chain_link(pool);
        if (cl == NULL) {
            return NGX_ERROR;
        }

        cl->buf = in->buf;
        *ll = cl;
        ll = &cl->next;
        in = in->next;
    }

    *ll = NULL;

    return NGX_OK;
}


ngx_chain_t *
ngx_chain_get_free_buf(ngx_pool_t *p, ngx_chain_t **free)
{
    ngx_chain_t  *cl;

    if (*free) {
        cl = *free;
        *free = cl->next;
        cl->next = NULL;
        return cl;
    }

    cl = ngx_alloc_chain_link(p);
    if (cl == NULL) {
        return NULL;
    }

    cl->buf = ngx_calloc_buf(p);
    if (cl->buf == NULL) {
        return NULL;
    }

    cl->next = NULL;

    return cl;
}


void
ngx_chain_update_chains(ngx_pool_t *p, ngx_chain_t **free, ngx_chain_t **busy,
    ngx_chain_t **out, ngx_buf_tag_t tag)
{
    ngx_chain_t  *cl;

    if (*busy == NULL) {
        *busy = *out;

    } else {
        for (cl = *busy; cl->next; cl = cl->next) { /* void */ }

        cl->next = *out;
    }

    *out = NULL;

    while (*busy) {
        cl = *busy;

        if (ngx_buf_size(cl->buf) != 0) {
            break;
        }

        if (cl->buf->tag != tag) {
            *busy = cl->next;
            ngx_free_chain(p, cl);
            continue;
        }

        cl->buf->pos = cl->buf->start;
        cl->buf->last = cl->buf->start;

        *busy = cl->next;
        cl->next = *free;
        *free = cl;
    }
}