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/* 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.
*/
/**
* @file ap_expr.h
* @brief Expression parser
*/
#ifndef AP_EXPR_H
#define AP_EXPR_H
#include "httpd.h"
#include "ap_regex.h"
#ifdef __cplusplus
extern "C" {
#endif
/* conditional expression parser stuff */
typedef enum {
TOKEN_STRING,
TOKEN_RE,
TOKEN_AND,
TOKEN_OR,
TOKEN_NOT,
TOKEN_EQ,
TOKEN_NE,
TOKEN_RBRACE,
TOKEN_LBRACE,
TOKEN_GROUP,
TOKEN_GE,
TOKEN_LE,
TOKEN_GT,
TOKEN_LT,
TOKEN_ACCESS
} token_type_t;
typedef struct {
token_type_t type;
const char *value;
#ifdef DEBUG_INCLUDE
const char *s;
#endif
} token_t;
typedef struct parse_node {
struct parse_node *parent;
struct parse_node *left;
struct parse_node *right;
token_t token;
int value;
int done;
#ifdef DEBUG_INCLUDE
int dump_done;
#endif
} ap_parse_node_t;
typedef struct {
const char *source;
const char *rexp;
apr_size_t nsub;
ap_regmatch_t match[AP_MAX_REG_MATCH];
} backref_t;
typedef const char *(*string_func_t)(request_rec*, const char*);
typedef int (*opt_func_t)(request_rec*, ap_parse_node_t*, string_func_t);
/**
* Parse an expression into a parse tree
* @param pool Pool
* @param expr The expression to parse
* @param was_error On return, set to zero if parse successful, nonzero on error
* @return The parse tree
*/
AP_DECLARE(ap_parse_node_t*) ap_expr_parse(apr_pool_t *pool, const char *expr,
int *was_error);
/**
* Evaluate a parse tree
* @param r The current request
* @param root The root node of the parse tree
* @param was_error On return, set to zero if parse successful, nonzero on error
* @param reptr Regular expression memory for backreferencing if a regexp was parsed
* @param string_func String parser function - perform variable substitutions
* Use ap_expr_string where applicable
* @param eval_func Option evaluation function (e.g. -A filename)
* @return the value the expression parsed to
*/
AP_DECLARE(int) ap_expr_eval(request_rec *r, ap_parse_node_t *root,
int *was_error, backref_t **reptr,
string_func_t string_func, opt_func_t eval_func);
/**
* Evaluate an expression. This is functionally equivalent to
* ap_expr_parse followed by ap_expr_eval, but faster and more efficient
* when an expression only needs to be parsed once and discarded.
* @param r The current request
* @param expr The expression to parse
* @param was_error On return, set to zero if parse successful, nonzero on error
* @param reptr Regular expression memory for backreferencing if a regexp was parsed
* @param string_func String parser function - perform variable substitutions
* Use ap_expr_string where applicable
* @param eval_func Option evaluation function (e.g. -A filename)
* @return the value the expression parsed to
*/
AP_DECLARE(int) ap_expr_evalstring(request_rec *r, const char *expr,
int *was_error, backref_t **reptr,
string_func_t string_func,
opt_func_t eval_func);
/**
* Internal initialisation of ap_expr (for httpd)
* @param pool Pool
* @return APR_SUCCESS or error
*/
AP_DECLARE(apr_status_t) ap_expr_init(apr_pool_t *pool);
/**
* Default string evaluation function for passing to ap_expr_eval and
* ap_expr_evalstring. Use this (and update as necessary) to offer
* a consistent expression syntax across different modules.
* Supports the following:
* $req{foo} - request header "foo"
* $resp{foo} - response header "foo"
* $env{foo} - environment variable "foo"
* $handler - r->handler
* $content-type - r->content_type
* Other strings are returned unmodified.
* @param r The current request
* @param str The string to evaluate
* @return The evaluated string
*/
AP_DECLARE_NONSTD(const char*) ap_expr_string(request_rec *r,
const char *str);
#ifdef __cplusplus
}
#endif
#endif /* AP_EXPR_H */
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