buckets/apr_buckets_simple.c

/* ====================================================================
 * The Apache Software License, Version 1.1
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 * Copyright (c) 2000 The Apache Software Foundation.  All rights
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 */

#include "ap_buckets.h"
#include <stdlib.h>

/*
 * We can't simplify this function by using an ap_bucket_make function
 * because we aren't sure of the exact type of this bucket.
 */
static apr_status_t simple_copy(ap_bucket *a, ap_bucket **c)
{
    ap_bucket *b;
    ap_bucket_simple *ad, *bd;

    b = malloc(sizeof(*b)); 
    if (b == NULL) {
	return APR_ENOMEM;
    }
    bd = malloc(sizeof(*bd));
    if (bd == NULL) {
	free(b);
	return APR_ENOMEM;
    }
    *b = *a;
    ad = a->data;
    b->data = bd;
    *bd = *ad;

    *c = b;

    return APR_SUCCESS;
}

static apr_status_t simple_split(ap_bucket *a, apr_off_t point)
{
    ap_bucket *b;
    ap_bucket_simple *ad, *bd;
    apr_status_t rv;

    if (point < 0 || point > a->length) {
	return APR_EINVAL;
    }

    rv = simple_copy(a, &b);
    if (rv != APR_SUCCESS) {
        return rv;
    }

    ad = a->data;
    bd = b->data;

    a->length = point;
    ad->end = ad->start + point;
    b->length -= point;
    bd->start += point;

    AP_BUCKET_INSERT_AFTER(a, b);

    return APR_SUCCESS;
}

static apr_status_t simple_read(ap_bucket *b, const char **str, 
				apr_size_t *len, ap_read_type block)
{
    ap_bucket_simple *bd = b->data;
    *str = bd->start;
    *len = bd->end - bd->start;
    return APR_SUCCESS;
}

APR_DECLARE(ap_bucket *) ap_bucket_make_immortal(ap_bucket *b,
		const char *buf, apr_size_t length)
{
    ap_bucket_simple *bd;

    bd = malloc(sizeof(*bd));
    if (bd == NULL) {
	return NULL;
    }

    bd->start   = buf;
    bd->end     = buf+length;

    b->type     = &ap_immortal_type;
    b->length   = length;
    b->data     = bd;

    return b;
}

APR_DECLARE(ap_bucket *) ap_bucket_create_immortal(
		const char *buf, apr_size_t length)
{
    ap_bucket_do_create(ap_bucket_make_immortal(b, buf, length));
}

/*
 * XXX: This function could do with some tweaking to reduce memory
 * usage in various cases, e.g. share buffers in the heap between all
 * the buckets that are set aside, or even spool set-aside data to
 * disk if it gets too voluminous (but if it does then that's probably
 * a bug elsewhere). There should probably be a ap_brigade_setaside()
 * function that co-ordinates the action of all the bucket setaside
 * functions to improve memory efficiency.
 */
static apr_status_t transient_setaside(ap_bucket *b)
{
    ap_bucket_simple *bd;
    const char *start, *end;
    apr_size_t w;
    
    bd = b->data;
    start = bd->start;
    end = bd->end;
    /* XXX: handle small heap buckets */
    b = ap_bucket_make_heap(b, start, end-start, 1, &w);
    if (b == NULL || w != end-start) {
	return APR_ENOMEM;
    }
    free(bd);
    return APR_SUCCESS;
}

APR_DECLARE(ap_bucket *) ap_bucket_make_transient(ap_bucket *b,
		const char *buf, apr_size_t length)
{
    b = ap_bucket_make_immortal(b, buf, length);
    if (b == NULL) {
	return NULL;
    }
    b->type = &ap_transient_type;
    return b;
}

APR_DECLARE(ap_bucket *) ap_bucket_create_transient(
		const char *buf, apr_size_t length)
{
    ap_bucket_do_create(ap_bucket_make_transient(b, buf, length));
}

const ap_bucket_type ap_immortal_type = {
    "IMMORTAL", 5,
    free,
    simple_read,
    ap_bucket_setaside_notimpl,
    simple_split,
    simple_copy
};

APR_DECLARE_DATA const ap_bucket_type ap_transient_type = {
    "TRANSIENT", 5,
    ap_bucket_destroy_notimpl, 
    simple_read,
    transient_setaside,
    simple_split,
    simple_copy
};