/* Licensed to the Apache Software Foundation (ASF) under one or more

 * contributor license agreements.  See the NOTICE file distributed with

 * this work for additional information regarding copyright ownership.

 * The ASF licenses this file to You 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.

 */

/*

 * mod_bucketeer.c: split buckets whenever we find a control-char

 *

 * Written by Ian Holsman

 *

 */

#include "httpd.h"

#include "http_config.h"

#include "http_log.h"

#include "apr_strings.h"

#include "apr_general.h"

#include "util_filter.h"

#include "apr_buckets.h"

#include "http_request.h"

#include "http_protocol.h"

static const char bucketeerFilterName[] = "BUCKETEER";

module AP_MODULE_DECLARE_DATA bucketeer_module;

typedef struct bucketeer_filter_config_t

{

    char bucketdelimiter;

    char passdelimiter;

    char flushdelimiter;

} bucketeer_filter_config_t;

static void *create_bucketeer_server_config(apr_pool_t *p, server_rec *s)

{

    bucketeer_filter_config_t *c = apr_pcalloc(p, sizeof *c);

    c->bucketdelimiter = 0x02; /* ^B */

    c->passdelimiter = 0x10;   /* ^P */

    c->flushdelimiter = 0x06;  /* ^F */

    return c;

}

typedef struct bucketeer_ctx_t

{

    apr_bucket_brigade *bb;

} bucketeer_ctx_t;

static apr_status_t bucketeer_out_filter(ap_filter_t *f,

                                         apr_bucket_brigade *bb)

{

    apr_bucket *e;

    request_rec *r = f->r;

    bucketeer_ctx_t *ctx = f->ctx;

    bucketeer_filter_config_t *c;

    c = ap_get_module_config(r->server->module_config, &bucketeer_module);

    /* If have a context, it means we've done this before successfully. */

    if (!ctx) {

        if (!r->content_type || strncmp(r->content_type, "text/", 5)) {

            ap_remove_output_filter(f);

            return ap_pass_brigade(f->next, bb);

        }

        /* We're cool with filtering this. */

        ctx = f->ctx = apr_pcalloc(f->r->pool, sizeof(*ctx));

        ctx->bb = apr_brigade_create(f->r->pool, f->c->bucket_alloc);

        apr_table_unset(f->r->headers_out, "Content-Length");

    }

    for (e = APR_BRIGADE_FIRST(bb);

         e != APR_BRIGADE_SENTINEL(bb);

         e = APR_BUCKET_NEXT(e))

    {

        const char *data;

        apr_size_t len, i, lastpos;

        if (APR_BUCKET_IS_EOS(e)) {

            APR_BUCKET_REMOVE(e);

            APR_BRIGADE_INSERT_TAIL(ctx->bb, e);

            /* Okay, we've seen the EOS.

             * Time to pass it along down the chain.

             */

            return ap_pass_brigade(f->next, ctx->bb);

        }

        if (APR_BUCKET_IS_FLUSH(e)) {

            /*

             * Ignore flush buckets for the moment..

             * we decide what to stream

             */

            continue;

        }

        if (APR_BUCKET_IS_METADATA(e)) {

            /* metadata bucket */

            apr_bucket *cpy;

            apr_bucket_copy(e, &cpy);

            APR_BRIGADE_INSERT_TAIL(ctx->bb, cpy);

            continue;

        }

        /* read */

        apr_bucket_read(e, &data, &len, APR_BLOCK_READ);

        if (len > 0) {

            lastpos = 0;

            for (i = 0; i < len; i++) {

                if (data[i] == c->flushdelimiter ||

                    data[i] == c->bucketdelimiter ||

                    data[i] == c->passdelimiter) {

                    apr_bucket *p;

                    if (i - lastpos > 0) {

                        p = apr_bucket_pool_create(apr_pmemdup(f->r->pool,

                                                               &data[lastpos],

                                                               i - lastpos),

                                                    i - lastpos,

                                                    f->r->pool,

                                                    f->c->bucket_alloc);

                        APR_BRIGADE_INSERT_TAIL(ctx->bb, p);

                    }

                    lastpos = i + 1;

                    if (data[i] == c->flushdelimiter) {

                        p = apr_bucket_flush_create(f->c->bucket_alloc);

                        APR_BRIGADE_INSERT_TAIL(ctx->bb, p);

                    }

                    if (data[i] == c->passdelimiter) {

                        apr_status_t rv;

                        rv = ap_pass_brigade(f->next, ctx->bb);

                        if (rv) {

                            return rv;

                        }

                    }

                }

            }

            /* XXX: really should append this to the next 'real' bucket */

            if (lastpos < i) {

                apr_bucket *p;

                p = apr_bucket_pool_create(apr_pmemdup(f->r->pool,

                                                       &data[lastpos],

                                                       i - lastpos),

                                           i - lastpos,

                                           f->r->pool,

                                           f->c->bucket_alloc);

                lastpos = i;

                APR_BRIGADE_INSERT_TAIL(ctx->bb, p);

            }

        }

    }

    return APR_SUCCESS;

}

static void register_hooks(apr_pool_t * p)

{

    ap_register_output_filter(bucketeerFilterName, bucketeer_out_filter,

                              NULL, AP_FTYPE_RESOURCE-1);

}

static const command_rec bucketeer_filter_cmds[] = {

    {NULL}

};

AP_DECLARE_MODULE(bucketeer) = {

    STANDARD20_MODULE_STUFF,

    NULL,

    NULL,

    create_bucketeer_server_config,

    NULL,

    bucketeer_filter_cmds,

    register_hooks

};