/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2004 Merjis Ltd.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Apache" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    nor may "Apache" appear in their name, without prior written
 *    permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 */

/*
 * mod_acquire: Implement Zope-like acquisition for Apache.
 *
 * By Richard W.M. Jones <rich@annexia.org>.
 * Copyright (C) 2004 Merjis Ltd.  http://www.merjis.com/
 */

#include "httpd.h"
#include "http_config.h"
#include "http_request.h"
#include "http_core.h"
#include "http_protocol.h"
#include "http_main.h"
#include "http_log.h"
#include "util_script.h"

typedef struct {
  int acquisition;		/* Set if enabled for this directory. */
} acquire_dir_config;

module acquire_module;

static void *
create_acquire_dir_config (pool *p, char *dummy)
{
  acquire_dir_config *new =
    (acquire_dir_config *) ap_palloc(p, sizeof (acquire_dir_config));

  new->acquisition = 0;
  return new;
}

static void *
merge_acquire_dir_configs (pool *p, void *basev, void *addv)
{
  acquire_dir_config *base = (acquire_dir_config *) basev;
  acquire_dir_config *add = (acquire_dir_config *) addv;
  acquire_dir_config *new =
    (acquire_dir_config *) ap_palloc (p, sizeof (acquire_dir_config));

  new->acquisition = add->acquisition || base->acquisition;
  return new;
}

static const char *
acquire (cmd_parms *cmd, acquire_dir_config *m, int enabled)
{
  m->acquisition = enabled;
  return NULL;
}

static const command_rec acquire_cmds[] =
{
  {"Acquire", acquire, NULL, ACCESS_CONF | RSRC_CONF, FLAG,
   "enable acquisition in this scope"},
  {NULL}
};

static char *
rindex_from (char *str, char *from, char c)
{
  while (str <= from)
    {
      if (*from == c) return from;
      from--;
    }
  return 0;
}

static int
no_file (request_rec *r)
{
  return
    r->uri[strlen (r->uri) - 1] != '/' &&
    (r->finfo.st_mode == 0 || (r->path_info && *r->path_info));
}

static char *
uri_above (request_rec *r)
{
  char *pi, *pj, *new_uri;
  int i, j;

  pi = rindex (r->uri, '/');
  if (pi == 0 || pi == r->uri) return 0;
  i = pi - r->uri;

  pj = rindex_from (r->uri, pi-1, '/');
  if (pj == 0) return 0;
  j = pj - r->uri;

  new_uri = ap_pstrdup (r->pool, r->uri);
  memmove (new_uri + j, new_uri + i, strlen (new_uri + i) + 1);
  return new_uri;
}

static int
acquire_fixups (request_rec *r)
{
  acquire_dir_config *conf = (acquire_dir_config *)
    ap_get_module_config (r->per_dir_config, &acquire_module);

  if (! conf->acquisition) return DECLINED;

  /* If the file exists, the core default_handler or another handler
   * will serve it.
   */
  if (! no_file (r)) return DECLINED;

  /* Otherwise, it's a missing file, so a candidate for acquisition. */
  r->handler = "acquire-handler";
  return OK;
}

static int
acquire_handler (request_rec *r)
{
  char *new_uri;
  request_rec *rr;

  /* This is a candidate for acquisition (file not found) so do it. */
  new_uri = uri_above (r);
  if (!new_uri) return DECLINED;

  /* XXX ap_escape_uri? */
  /* ap_sub_req_lookup_uri does everything up to running the handler.
   * ap_run_sub_req actually runs the handler.
   */
  rr = ap_sub_req_lookup_uri (new_uri, r);
  if (!rr) return DECLINED;	/* Display error message? */
  ap_run_sub_req (rr);		/* Check error return?  Do what?? */
  ap_destroy_sub_req (rr);
  return OK;
}

static const handler_rec acquire_handlers[] =
{
    {"acquire-handler", acquire_handler},
    {NULL}
};

module acquire_module =
{
    STANDARD_MODULE_STUFF,
    NULL,			/* initializer */
    create_acquire_dir_config,	/* dir config creater */
    merge_acquire_dir_configs,	/* dir merger --- default is to override */
    NULL,			/* server config */
    NULL,			/* merge server config */
    acquire_cmds,		/* command table */
    acquire_handlers,		/* handlers */
    NULL,			/* filename translation */
    NULL,			/* check_user_id */
    NULL,			/* check auth */
    NULL,			/* check access */
    NULL,			/* type_checker */
    acquire_fixups,		/* fixups */
    NULL,			/* logger */
    NULL,			/* header parser */
    NULL,			/* child_init */
    NULL,			/* child_exit */
    NULL			/* post read-request */
};