/* 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.
 */

#ifndef APACHE_HTTP_REQUEST_H
#define APACHE_HTTP_REQUEST_H

#include "apr_hooks.h"
#include "util_filter.h"

#ifdef __cplusplus
extern "C" {
#endif

#define AP_SUBREQ_NO_ARGS 0
#define AP_SUBREQ_MERGE_ARGS 1

/**
 * @file http_request.h
 * @brief Apache Request library
 */

/* http_request.c is the code which handles the main line of request
 * processing, once a request has been read in (finding the right per-
 * directory configuration, building it if necessary, and calling all
 * the module dispatch functions in the right order).
 *
 * The pieces here which are public to the modules, allow them to learn
 * how the server would handle some other file or URI, or perhaps even
 * direct the server to serve that other file instead of the one the
 * client requested directly.
 *
 * There are two ways to do that.  The first is the sub_request mechanism,
 * which handles looking up files and URIs as adjuncts to some other
 * request (e.g., directory entries for multiviews and directory listings);
 * the lookup functions stop short of actually running the request, but
 * (e.g., for includes), a module may call for the request to be run
 * by calling run_sub_req.  The space allocated to create sub_reqs can be
 * reclaimed by calling destroy_sub_req --- be sure to copy anything you care
 * about which was allocated in its apr_pool_t elsewhere before doing this.
 */

/**
 * An internal handler used by the ap_process_request, all subrequest mechanisms
 * and the redirect mechanism.
 * @param r The request, subrequest or internal redirect to pre-process
 * @return The return code for the request
 */
AP_DECLARE(int) ap_process_request_internal(request_rec *r);

/**
 * Create a subrequest from the given URI.  This subrequest can be
 * inspected to find information about the requested URI
 * @param new_uri The URI to lookup
 * @param r The current request
 * @param next_filter The first filter the sub_request should use.  If this is
 *                    NULL, it defaults to the first filter for the main request
 * @return The new request record
 * @deffunc request_rec * ap_sub_req_lookup_uri(const char *new_uri, const request_rec *r)
 */
AP_DECLARE(request_rec *) ap_sub_req_lookup_uri(const char *new_uri,
                                                const request_rec *r,
                                                ap_filter_t *next_filter);

/**
 * Create a subrequest for the given file.  This subrequest can be
 * inspected to find information about the requested file
 * @param new_file The file to lookup
 * @param r The current request
 * @param next_filter The first filter the sub_request should use.  If this is
 *                    NULL, it defaults to the first filter for the main request
 * @return The new request record
 * @deffunc request_rec * ap_sub_req_lookup_file(const char *new_file, const request_rec *r)
 */
AP_DECLARE(request_rec *) ap_sub_req_lookup_file(const char *new_file,
                                              const request_rec *r,
                                              ap_filter_t *next_filter);
/**
 * Create a subrequest for the given apr_dir_read result.  This subrequest 
 * can be inspected to find information about the requested file
 * @param finfo The apr_dir_read result to lookup
 * @param r The current request
 * @param subtype What type of subrequest to perform, one of;
 * <PRE>
 *      AP_SUBREQ_NO_ARGS     ignore r->args and r->path_info
 *      AP_SUBREQ_MERGE_ARGS  merge r->args and r->path_info
 * </PRE>
 * @param next_filter The first filter the sub_request should use.  If this is
 *                    NULL, it defaults to the first filter for the main request
 * @return The new request record
 * @deffunc request_rec * ap_sub_req_lookup_dirent(apr_finfo_t *finfo, int subtype, const request_rec *r)
 * @tip The apr_dir_read flags value APR_FINFO_MIN|APR_FINFO_NAME flag is the 
 * minimum recommended query if the results will be passed to apr_dir_read.
 * The file info passed must include the name, and must have the same relative
 * directory as the current request.
 */
AP_DECLARE(request_rec *) ap_sub_req_lookup_dirent(const apr_finfo_t *finfo,
                                                   const request_rec *r,
                                                   int subtype,
                                                   ap_filter_t *next_filter);
/**
 * Create a subrequest for the given URI using a specific method.  This
 * subrequest can be inspected to find information about the requested URI
 * @param method The method to use in the new subrequest
 * @param new_uri The URI to lookup
 * @param r The current request
 * @param next_filter The first filter the sub_request should use.  If this is
 *                    NULL, it defaults to the first filter for the main request
 * @return The new request record
 * @deffunc request_rec * ap_sub_req_method_uri(const char *method, const char *new_uri, const request_rec *r)
 */
AP_DECLARE(request_rec *) ap_sub_req_method_uri(const char *method,
                                                const char *new_uri,
                                                const request_rec *r,
                                                ap_filter_t *next_filter);
/**
 * An output filter to strip EOS buckets from sub-requests.  This always
 * has to be inserted at the end of a sub-requests filter stack.
 * @param f The current filter
 * @param bb The brigade to filter
 * @deffunc apr_status_t ap_sub_req_output_filter(ap_filter_t *f, apr_bucket_brigade *bb)
 */
AP_CORE_DECLARE_NONSTD(apr_status_t) ap_sub_req_output_filter(ap_filter_t *f,
                                                        apr_bucket_brigade *bb);

/**
 * Run the handler for the subrequest
 * @param r The subrequest to run
 * @return The return code for the subrequest
 * @deffunc int ap_run_sub_req(request_rec *r)
 */
AP_DECLARE(int) ap_run_sub_req(request_rec *r);

/**
 * Free the memory associated with a subrequest
 * @param r The subrequest to finish
 * @deffunc void ap_destroy_sub_req(request_rec *r)
 */
AP_DECLARE(void) ap_destroy_sub_req(request_rec *r);

/*
 * Then there's the case that you want some other request to be served
 * as the top-level request INSTEAD of what the client requested directly.
 * If so, call this from a handler, and then immediately return OK.
 */

/**
 * Redirect the current request to some other uri
 * @param new_uri The URI to replace the current request with
 * @param r The current request
 * @deffunc void ap_internal_redirect(const char *new_uri, request_rec *r)
 */
AP_DECLARE(void) ap_internal_redirect(const char *new_uri, request_rec *r);

/**
 * This function is designed for things like actions or CGI scripts, when
 * using AddHandler, and you want to preserve the content type across
 * an internal redirect.
 * @param new_uri The URI to replace the current request with.
 * @param r The current request
 * @deffunc void ap_internal_redirect_handler(const char *new_uri, request_rec *r)
 */
AP_DECLARE(void) ap_internal_redirect_handler(const char *new_uri, request_rec *r);

/**
 * Redirect the current request to a sub_req, merging the pools
 * @param sub_req A subrequest created from this request
 * @param r The current request
 * @deffunc void ap_internal_fast_redirect(request_rec *sub_req, request_rec *r)
 * @tip the sub_req's pool will be merged into r's pool, be very careful
 * not to destroy this subrequest, it will be destroyed with the main request!
 */
AP_DECLARE(void) ap_internal_fast_redirect(request_rec *sub_req, request_rec *r);

/**