/* 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 _MOD_INCLUDE_H
#define _MOD_INCLUDE_H 1

#include "apr_pools.h"
#include "apr_optional.h"

#define STARTING_SEQUENCE "<!--#"
#define ENDING_SEQUENCE "-->"

#define DEFAULT_ERROR_MSG "[an error occurred while processing this directive]"
#define DEFAULT_TIME_FORMAT "%A, %d-%b-%Y %H:%M:%S %Z"
#define SIZEFMT_BYTES 0
#define SIZEFMT_KMG 1
#define TMP_BUF_SIZE 1024
#if APR_CHARSET_EBCDIC
#define RAW_ASCII_CHAR(ch)  apr_xlate_conv_byte(ap_hdrs_from_ascii, (unsigned char)ch)
#else /*APR_CHARSET_EBCDIC*/
#define RAW_ASCII_CHAR(ch)  (ch)
#endif /*APR_CHARSET_EBCDIC*/

/****************************************************************************
 * Used to keep context information during parsing of a request for SSI tags.
 * This is especially useful if the tag stretches across multiple buckets or
 * brigades. This keeps track of which buckets need to be replaced with the
 * content generated by the SSI tag.
 *
 * state: PRE_HEAD - State prior to finding the first character of the 
 *                   STARTING_SEQUENCE. Next state is PARSE_HEAD.
 *        PARSE_HEAD - State entered once the first character of the
 *                     STARTING_SEQUENCE is found and exited when the
 *                     the full STARTING_SEQUENCE has been matched or
 *                     a match failure occurs. Next state is PRE_HEAD
 *                     or PARSE_TAG.
 *        PARSE_TAG - State entered once the STARTING sequence has been
 *                    matched. It is exited when the first character in
 *                    ENDING_SEQUENCE is found. Next state is PARSE_TAIL.
 *        PARSE_TAIL - State entered from PARSE_TAG state when the first
 *                     character in ENDING_SEQUENCE is encountered. This
 *                     state is exited when the ENDING_SEQUENCE has been
 *                     completely matched, or when a match failure occurs.
 *                     Next state is PARSE_TAG or PARSED.
 *        PARSED - State entered from PARSE_TAIL once the complete 
 *                 ENDING_SEQUENCE has been matched. The SSI tag is
 *                 processed and the SSI buckets are replaced with the
 *                 SSI content during this state.
 * parse_pos: Current matched position within the STARTING_SEQUENCE or
 *            ENDING_SEQUENCE during the PARSE_HEAD and PARSE_TAIL states.
 *            This is especially useful when the sequence spans brigades.
 * X_start_bucket: These point to the buckets containing the first character
 *                 of the STARTING_SEQUENCE, the first non-whitespace
 *                 character of the tag, and the first character in the
 *                 ENDING_SEQUENCE (head_, tag_, and tail_ respectively).
 *                 The buckets are kept intact until the PARSED state is
 *                 reached, at which time the tag is consolidated and the
 *                 buckets are released. The buckets that these point to
 *                 have all been set aside in the ssi_tag_brigade (along
 *                 with all of the intervening buckets).
 * X_start_index: The index points within the specified bucket contents
 *                where the first character of the STARTING_SEQUENCE,
 *                the first non-whitespace character of the tag, and the
 *                first character in the ENDING_SEQUENCE can be found
 *                (head_, tag_, and tail_ respectively).
 * combined_tag: Once the PARSED state is reached the tag is collected from
 *               the bucket(s) in the ssi_tag_brigade into this contiguous
 *               buffer. The buckets in the ssi_tag_brigade are released
 *               and the tag is processed.
 * curr_tag_pos: Ptr to the combined_tag buffer indicating the current
 *               parse position.
 * tag_length: The number of bytes in the actual tag (excluding the
 *             STARTING_SEQUENCE, leading and trailing whitespace,
 *             and ENDING_SEQUENCE). This length is computed as the
 *             buckets are parsed and set aside during the PARSE_TAG state.
 * ssi_tag_brigade: The temporary brigade used by this filter to set aside
 *                  the buckets containing parts of the ssi tag and headers.
 */

/* I keep this stuff here, because of binary compat. It probably doesn't care,
 * but who knows ...?
 */
#ifdef MOD_INCLUDE_REDESIGN
typedef enum {PRE_HEAD, BLOW_PARSE_HEAD, BLOW_PARSE_DIRECTIVE, PARSE_TAG,
              BLOW_PARSE_TAIL, PARSED} states;
#else
typedef enum {PRE_HEAD, PARSE_HEAD, PARSE_DIRECTIVE, PARSE_TAG, PARSE_TAIL,
              PARSED} states;
#endif

/** forward referenced as it needs to be held on the context */
typedef struct bndm_t bndm_t;

typedef struct include_filter_ctx {
    states       state;
    long         flags;    /* See the FLAG_XXXXX definitions. */
    int          if_nesting_level;
    apr_size_t   parse_pos;
    int          bytes_parsed;
    apr_status_t status;
    int          output_now;
    int          output_flush;
    
    apr_bucket   *head_start_bucket;
    apr_size_t   head_start_index;

    apr_bucket   *tag_start_bucket;
    apr_size_t   tag_start_index;

    apr_bucket   *tail_start_bucket;
    apr_size_t   tail_start_index;

    char        *combined_tag;
    char        *curr_tag_pos;
    apr_size_t   directive_length;
    apr_size_t   tag_length;

    char         *error_str;
    char         *error_str_override;
    char         *time_str;
    char         *time_str_override;
    apr_pool_t   *pool;

    apr_bucket_brigade *ssi_tag_brigade;
    bndm_t       *start_seq_pat;
    char         *start_seq;
    int          start_seq_len;
    char         *end_seq;
    char         *re_string;
    regmatch_t   (*re_result)[10];
} include_ctx_t;

/* These flags are used to set flag bits. */
#define FLAG_PRINTING         0x00000001  /* Printing conditional lines. */
#define FLAG_COND_TRUE        0x00000002  /* Conditional eval'd to true. */
#define FLAG_SIZE_IN_BYTES    0x00000004  /* Sizes displayed in bytes.   */
#define FLAG_NO_EXEC          0x00000008  /* No Exec in current context. */

/* These flags are used to clear flag bits. */
#define FLAG_SIZE_ABBREV      0xFFFFFFFB  /* Reset SIZE_IN_BYTES bit.    */
#define FLAG_CLEAR_PRINT_COND 0xFFFFFFFC  /* Reset PRINTING and COND_TRUE*/
#define FLAG_CLEAR_PRINTING   0xFFFFFFFE  /* Reset just PRINTING bit.    */

#define CREATE_ERROR_BUCKET(cntx, t_buck, h_ptr, ins_head)        \
{                                                                 \
    /* XXX: it'd probably be nice to use a pool bucket here */    \
    t_buck = apr_bucket_heap_create(cntx->error_str,              \
                                    strlen(cntx->error_str),      \
                                    NULL, h_ptr->list);           \
    APR_BUCKET_INSERT_BEFORE(h_ptr, t_buck);                      \
                                                                  \
    if (ins_head == NULL) {                                       \
        ins_head = t_buck;                                        \
    }                                                             \
}

/* Make sure to check the return code rc. If it is anything other
 *   than APR_SUCCESS, then you should return this value up the
 *   call chain.
 */
#define SPLIT_AND_PASS_PRETAG_BUCKETS(brgd, cntxt, next, rc)          \
if ((APR_BRIGADE_EMPTY((cntxt)->ssi_tag_brigade)) &&                  \
    ((cntxt)->head_start_bucket != NULL)) {                           \
    apr_bucket_brigade *tag_plus;                                     \
                                                                      \
    tag_plus = apr_brigade_split((brgd), (cntxt)->head_start_bucket); \
    if ((cntxt)->output_flush) {                                      \
        APR_BRIGADE_INSERT_TAIL((brgd), apr_bucket_flush_create((brgd)->bucket_alloc));   \
    }                                                                 \
    (rc) = ap_pass_brigade((next), (brgd));                           \
    (cntxt)->bytes_parsed = 0;                                        \
    (brgd) = tag_plus;                                                \
}


typedef int (include_handler_fn_t)(include_ctx_t *ctx, apr_bucket_brigade **bb,
                       request_rec *r, ap_filter_t *f, apr_bucket *head_ptr, 
                       apr_bucket **inserted_head);

APR_DECLARE_OPTIONAL_FN(void, ap_ssi_get_tag_and_value, (include_ctx_t *ctx,
                                                         char **tag,
                                                         char **tag_val,
                                                         int dodecode));
APR_DECLARE_OPTIONAL_FN(char*, ap_ssi_parse_string, (request_rec *r,
                                                    include_ctx_t *ctx,
                                                    const char *in,
                                                    char *out,
                                                    apr_size_t length,
                                                    int leave_name));
APR_DECLARE_OPTIONAL_FN(void, ap_register_include_handler, 
                        (char *tag, include_handler_fn_t *func));

#endif /* MOD_INCLUDE */
