Function ap_varbuf_grow

server/util.c:2971–3059

}

AP_DECLARE(void) ap_varbuf_grow(struct ap_varbuf *vb, apr_size_t new_len)
{
    apr_memnode_t *new_node = NULL;
    apr_allocator_t *allocator;
    struct ap_varbuf_info *new_info;
    char *new;

    AP_DEBUG_ASSERT(vb->strlen == AP_VARBUF_UNKNOWN || vb->avail >= vb->strlen);

    if (new_len <= vb->avail)
        return;

    if (new_len < 2 * vb->avail && vb->avail < VARBUF_MAX_SIZE/2) {
        /* at least double the size, to avoid repeated reallocations */
        new_len = 2 * vb->avail;
    }
    else if (new_len > VARBUF_MAX_SIZE) {
        apr_abortfunc_t abort_fn = apr_pool_abort_get(vb->pool);
        ap_assert(abort_fn != NULL);
        abort_fn(APR_ENOMEM);
        return;
    }

    new_len++;  /* add space for trailing \0 */
    if (new_len <= VARBUF_SMALL_SIZE) {
        new_len = APR_ALIGN_DEFAULT(new_len);
        new = apr_palloc(vb->pool, new_len);
        if (vb->avail && vb->strlen != 0) {
            AP_DEBUG_ASSERT(vb->buf != NULL);
            AP_DEBUG_ASSERT(vb->buf != varbuf_empty);
            if (new == vb->buf + vb->avail + 1) {
                /* We are lucky: the new memory lies directly after our old
                 * buffer, we can now use both.
                 */
                vb->avail += new_len;
                return;
            }
            else {
                /* copy up to vb->strlen + 1 bytes */
                memcpy(new, vb->buf, vb->strlen == AP_VARBUF_UNKNOWN ?
                                     vb->avail + 1 : vb->strlen + 1);
            }
        }
        else {
            *new = '\0';
        }
        vb->avail = new_len - 1;
        vb->buf = new;
        return;
    }

    /* The required block is rather larger. Use allocator directly so that
     * the memory can be freed independently from the pool. */
    allocator = apr_pool_allocator_get(vb->pool);
    /* Happens if APR was compiled with APR_POOL_DEBUG */
    if (allocator == NULL) {
        apr_allocator_create(&allocator);
        ap_assert(allocator != NULL);