/* locks-table.c : operations on the `locks' table
 *
 * ====================================================================
 * Copyright (c) 2000-2004 CollabNet.  All rights reserved.
 *
 * This software is licensed as described in the file COPYING, which
 * you should have received as part of this distribution.  The terms
 * are also available at http://subversion.tigris.org/license-1.html.
 * If newer versions of this license are posted there, you may use a
 * newer version instead, at your option.
 *
 * This software consists of voluntary contributions made by many
 * individuals.  For exact contribution history, see the revision
 * history and logs, available at http://subversion.tigris.org/.
 * ====================================================================
 */

#include <string.h>
#include <assert.h>
#include "bdb_compat.h"

#include "svn_pools.h"
#include "dbt.h"
#include "../err.h"
#include "../fs.h"
#include "../util/skel.h"
#include "../util/fs_skels.h"
#include "../trail.h"
#include "../../libsvn_fs/fs-loader.h"
#include "bdb-err.h"
#include "locks-table.h"
#include "lock-tokens-table.h"



int
svn_fs_bdb__open_locks_table(DB **locks_p,
                             DB_ENV *env,
                             svn_boolean_t create)
{
  const u_int32_t open_flags = (create ? (DB_CREATE | DB_EXCL) : 0);
  DB *locks;
  int error;

  BDB_ERR(svn_fs_bdb__check_version());
  BDB_ERR(db_create(&locks, env, 0));
  error = locks->open(SVN_BDB_OPEN_PARAMS(locks, NULL),
                      "locks", 0, DB_BTREE,
                      open_flags, 0666);

  /* Create the table if it doesn't yet exist.  This is a form of
     automagical repository upgrading. */
  if (error == ENOENT && (! create))
    {
      BDB_ERR(locks->close(locks, 0));
      return svn_fs_bdb__open_locks_table(locks_p, env, TRUE);
    }
  BDB_ERR(error);

  *locks_p = locks;
  return 0;
}



svn_error_t *
svn_fs_bdb__lock_add(svn_fs_t *fs,
                     const char *lock_token,
                     svn_lock_t *lock,
                     trail_t *trail,
                     apr_pool_t *pool)
{
  base_fs_data_t *bfd = fs->fsap_data;
  skel_t *lock_skel;
  DBT key, value;

  /* Convert native type to skel. */
  SVN_ERR(svn_fs_base__unparse_lock_skel(&lock_skel, lock, pool));

  svn_fs_base__str_to_dbt(&key, lock_token);
  svn_fs_base__skel_to_dbt(&value, lock_skel, pool);
  svn_fs_base__trail_debug(trail, "lock", "add");
  SVN_ERR(BDB_WRAP(fs, "storing lock record",
                   bfd->locks->put(bfd->locks, trail->db_txn,
                                   &key, &value, 0)));

  return SVN_NO_ERROR;
}



svn_error_t *
svn_fs_bdb__lock_delete(svn_fs_t *fs,
                        const char *lock_token,
                        trail_t *trail,
                        apr_pool_t *pool)
{
  base_fs_data_t *bfd = fs->fsap_data;
  DBT key;
  int db_err;

  svn_fs_base__str_to_dbt(&key, lock_token);
  svn_fs_base__trail_debug(trail, "locks", "del");
  db_err = bfd->locks->del(bfd->locks, trail->db_txn, &key, 0);
  
  if (db_err == DB_NOTFOUND)
    return svn_fs_base__err_bad_lock_token(fs, lock_token);
  SVN_ERR(BDB_WRAP(fs, "deleting lock from 'locks' table", db_err));

  return SVN_NO_ERROR;
}



svn_error_t *
svn_fs_bdb__lock_get(svn_lock_t **lock_p,
                     svn_fs_t *fs,
                     const char *lock_token,
                     trail_t *trail,
                     apr_pool_t *pool)
{
  base_fs_data_t *bfd = fs->fsap_data;
  DBT key, value;
  int db_err;
  skel_t *skel;
  svn_lock_t *lock;

  svn_fs_base__trail_debug(trail, "lock", "get");
  db_err = bfd->locks->get(bfd->locks, trail->db_txn,
                           svn_fs_base__str_to_dbt(&key, lock_token),
                           svn_fs_base__result_dbt(&value),
                           0);
  svn_fs_base__track_dbt(&value, pool);

  if (db_err == DB_NOTFOUND)
    return svn_fs_base__err_bad_lock_token(fs, lock_token);
  SVN_ERR(BDB_WRAP(fs, "reading lock", db_err));

  /* Parse TRANSACTION skel */
  skel = svn_fs_base__parse_skel(value.data, value.size, pool);
  if (! skel)
    return svn_fs_base__err_corrupt_lock(fs, lock_token);

  /* Convert skel to native type. */
  SVN_ERR(svn_fs_base__parse_lock_skel(&lock, skel, pool));

  /* Possibly auto-expire the lock. */
  if (lock->expiration_date && (apr_time_now() > lock->expiration_date))
    {
      SVN_ERR(svn_fs_bdb__lock_delete(fs, lock_token, trail, pool));
      return svn_fs_base__err_lock_expired(fs, lock_token); 
    }

  *lock_p = lock;
  return SVN_NO_ERROR;
}


static svn_error_t *
get_lock(svn_lock_t **lock_p,
         svn_fs_t *fs,
         const char *path,
         const char *lock_token,
         trail_t *trail,
         apr_pool_t *pool)
{
  svn_error_t *err = SVN_NO_ERROR;
  *lock_p = NULL;

  /* Make sure the token points to an existing, non-expired lock, by
     doing a lookup in the `locks' table.  Use 'pool'. */
  err = svn_fs_bdb__lock_get(lock_p, fs, lock_token, trail, pool);
  if (err && ((err->apr_err == SVN_ERR_FS_LOCK_EXPIRED)
              || (err->apr_err == SVN_ERR_FS_BAD_LOCK_TOKEN)))
    {
      svn_error_clear(err);

      /* If `locks' doesn't have the lock, then we should lose it
         from `lock-tokens' table as well, then skip to the next
         matching path-key. */
      err = svn_fs_bdb__lock_token_delete(fs, path, trail, pool);
    }
  return err;
}


svn_error_t *
svn_fs_bdb__locks_get(svn_fs_t *fs,
                      const char *path,
                      svn_fs_get_locks_callback_t get_locks_func,
                      void *get_locks_baton,
                      trail_t *trail,
                      apr_pool_t *pool)
{
  base_fs_data_t *bfd = fs->fsap_data;
  DBC *cursor;
  DBT key, value;
  int db_err;
  apr_pool_t *subpool = svn_pool_create(pool);
  const char *lock_token;
  svn_lock_t *lock;
  svn_error_t *err;
  const char *lookup_path = path;

  /* First, try to lookup PATH itself. */
  err = svn_fs_bdb__lock_token_get(&lock_token, fs, path, trail, pool);
  if (err && ((err->apr_err == SVN_ERR_FS_LOCK_EXPIRED)
              || (err->apr_err == SVN_ERR_FS_BAD_LOCK_TOKEN)
              || (err->apr_err == SVN_ERR_FS_NO_SUCH_LOCK)))
    {
      svn_error_clear(err);
    }
  else if (err)
    {
      return err;
    }
  else
    {
      SVN_ERR(get_lock(&lock, fs, path, lock_token, trail, pool));
      if (lock && get_locks_func)
        SVN_ERR(get_locks_func(get_locks_baton, lock, pool));
    }

  /* Now go hunt for possible children of PATH. */
  if (strcmp(path, "/") != 0)
    lookup_path = apr_pstrcat(pool, path, "/", NULL);

  svn_fs_base__trail_debug(trail, "lock-tokens", "cursor");
  db_err = bfd->lock_tokens->cursor(bfd->lock_tokens, trail->db_txn,
                                    &cursor, 0);  
  SVN_ERR(BDB_WRAP(fs, "creating cursor for reading lock tokens", db_err));

  /* Since the key is going to be returned as well as the value make
     sure BDB malloc's the returned key.  */
  svn_fs_base__str_to_dbt(&key, lookup_path);
  key.flags |= DB_DBT_MALLOC;

  /* Get the first matching key that is either equal or greater than
     the one passed in, by passing in the DB_RANGE_SET flag.  */
  db_err = cursor->c_get(cursor, &key, svn_fs_base__result_dbt(&value),
                         DB_SET_RANGE);

  /* As long as the prefix of the returned KEY matches LOOKUP_PATH we
     know it is either LOOKUP_PATH or a decendant thereof.  */
  while ((! db_err) 
         && strncmp(lookup_path, key.data, strlen(lookup_path)) == 0)
    {
      const char *child_path;

      svn_pool_clear(subpool);

      svn_fs_base__track_dbt(&key, subpool);      
      svn_fs_base__track_dbt(&value, subpool);

      /* Create a usable path and token in temporary memory. */
      child_path = apr_pstrmemdup(subpool, key.data, key.size);
      lock_token = apr_pstrmemdup(subpool, value.data, value.size);

      /* Get the lock for CHILD_PATH.  */
      err = get_lock(&lock, fs, child_path, lock_token, trail, subpool);
      if (err)
        {
          cursor->c_close(cursor);
          return err;
        }

      /* Lock is verified, hand it off to our callback. */
      if (lock && get_locks_func)
        {
          err = get_locks_func(get_locks_baton, lock, subpool);
          if (err)
            {
              cursor->c_close(cursor);
              return err;
            }
        }

      svn_fs_base__result_dbt(&key);
      svn_fs_base__result_dbt(&value);
      db_err = cursor->c_get(cursor, &key, &value, DB_NEXT);
    }

  svn_pool_destroy(subpool);
  cursor->c_close(cursor);

  if (db_err && (db_err != DB_NOTFOUND)) 
    SVN_ERR(BDB_WRAP(fs, "fetching lock tokens", db_err));

  return SVN_NO_ERROR;
}