/*
 * activity.c: DeltaV activity handling
 *
 * ====================================================================
 * 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 <httpd.h>
#include <mod_dav.h>

#include <apr_dbm.h>

#include "svn_path.h"
#include "svn_fs.h"
#include "svn_repos.h"

#include "dav_svn.h"

#define ACTIVITY_DB "dav/activities"


const char *dav_svn_get_txn(const dav_svn_repos *repos,
                            const char *activity_id)
{
  apr_dbm_t *dbm;
  apr_status_t status;
  const char *pathname;
  apr_datum_t key;
  apr_datum_t value;
  const char *txn_name = NULL;

  pathname = svn_path_join(repos->fs_path, ACTIVITY_DB, repos->pool);
  status = apr_dbm_open(&dbm, pathname, APR_DBM_READONLY, 
                        APR_OS_DEFAULT, repos->pool);
  if (status != APR_SUCCESS)
    {
      /* ### let's just assume that any error means the DB doesn't exist,
         ### therefore, the activity/transaction doesn't exist */
      return NULL;
    }

  key.dptr = (char *)activity_id;
  key.dsize = strlen(activity_id) + 1;  /* null-term'd */
  if (apr_dbm_exists(dbm, key))
    {
      status = apr_dbm_fetch(dbm, key, &value);
      if (status != APR_SUCCESS)
        {
          /* ### again: assume failure means it doesn't exist */
          apr_dbm_close(dbm);
          return NULL;
        }
      txn_name = apr_pstrdup(repos->pool, value.dptr);   /* null-term'd */
      apr_dbm_freedatum(dbm, value);
    }

  apr_dbm_close(dbm);

  return txn_name;
}


dav_error *dav_svn_delete_activity(const dav_svn_repos *repos,
                                   const char *activity_id)
{
  dav_error *err = NULL;
  apr_dbm_t *dbm;
  apr_status_t status;
  const char *pathname;
  apr_datum_t key;
  apr_datum_t value;
  svn_fs_txn_t *txn;
  const char *txn_name;
  svn_error_t *serr;

  /* gstein sez: If the activity ID is not in the database, return a
     404.  If the transaction is not present or is immutable, return a
     204.  For all other failures, return a 500. */

  /* Open the activities database. */
  pathname = svn_path_join(repos->fs_path, ACTIVITY_DB, repos->pool);
  status = apr_dbm_open(&dbm, pathname, APR_DBM_READWRITE, 
                        APR_OS_DEFAULT, repos->pool);
  if (status != APR_SUCCESS)
    return dav_new_error(repos->pool, HTTP_NOT_FOUND, 0,
                         "could not open activities database.");

  /* Get the activity from the activity database. */
  key.dptr = (char *)activity_id;
  key.dsize = strlen(activity_id) + 1;  /* null-term'd */
  status = apr_dbm_fetch(dbm, key, &value);
  if (status == APR_SUCCESS)
    txn_name = value.dptr;
  else
    {
      apr_dbm_close(dbm);
      return dav_new_error(repos->pool, HTTP_NOT_FOUND, 0,
                           "could not find activity.");
    }

  /* After this point, we have to cleanup the value and database. */

  /* An empty txn_name indicates the transaction has been committed,
     so don't try to clean it up. */
  if (*txn_name)
    {
      /* Now, we attempt to delete TXN_NAME from the Subversion
         repository.  If we fail only because the transaction doesn't
         exist, don't sweat it (but then, also don't try to remove it). */
      if ((serr = svn_fs_open_txn(&txn, repos->fs, txn_name, repos->pool)))
        {
          if (serr->apr_err == SVN_ERR_FS_NO_SUCH_TRANSACTION)
            {
              svn_error_clear(serr);
              serr = SVN_NO_ERROR;
            }
          else
            {
              err = dav_svn_convert_err(serr, HTTP_INTERNAL_SERVER_ERROR,
                                        "could not open transaction.", 
                                        repos->pool);
              goto cleanup;
            }
        }
      else
        {
          serr = svn_fs_abort_txn(txn, repos->pool);
          if (serr)
            {
              err = dav_svn_convert_err(serr, HTTP_INTERNAL_SERVER_ERROR,
                                        "could not abort transaction.", 
                                        repos->pool);
              goto cleanup;
            }
        }
    }
  
  /* Finally, we remove the activity from the activities database. */
  status = apr_dbm_delete(dbm, key);
  if (status)
    {
      err = dav_new_error(repos->pool, HTTP_INTERNAL_SERVER_ERROR, 0,
                          "unable to remove activity.");
      goto cleanup;
    }

 cleanup:
  apr_dbm_freedatum(dbm, value);
  apr_dbm_close(dbm);

  return err;
}


dav_error *dav_svn_store_activity(const dav_svn_repos *repos,
                                  const char *activity_id,
                                  const char *txn_name)
{
  apr_dbm_t *dbm;
  apr_status_t status;
  const char *pathname;
  apr_datum_t key;
  apr_datum_t value;

  pathname = svn_path_join(repos->fs_path, ACTIVITY_DB, repos->pool);
  status = apr_dbm_open(&dbm, pathname, APR_DBM_RWCREATE, 
                        APR_OS_DEFAULT, repos->pool);
  if (status != APR_SUCCESS)
    {
      svn_error_t *serr = svn_error_wrap_apr(status, "Can't open activity db");

      return dav_svn_convert_err(serr, HTTP_INTERNAL_SERVER_ERROR,
                                 "could not open dbm files.", 
                                 repos->pool);
    }

  key.dptr = (char *)activity_id;
  key.dsize = strlen(activity_id) + 1;  /* null-term'd */
  value.dptr = (char *)txn_name;
  value.dsize = strlen(txn_name) + 1;   /* null-term'd */
  status = apr_dbm_store(dbm, key, value);
  apr_dbm_close(dbm);
  if (status != APR_SUCCESS)
    {
      svn_error_t *serr =
        svn_error_wrap_apr(status, "Can't close activity db");

      return dav_svn_convert_err(serr, HTTP_INTERNAL_SERVER_ERROR,
                                 "could not close dbm files.", 
                                 repos->pool);
    }

  return NULL;
}

dav_error *dav_svn_create_activity(const dav_svn_repos *repos,
                                   const char **ptxn_name,
                                   apr_pool_t *pool)
{
  svn_revnum_t rev;
  svn_fs_txn_t *txn;
  svn_error_t *serr;

  serr = svn_fs_youngest_rev(&rev, repos->fs, pool);
  if (serr != NULL)
    {
      return dav_svn_convert_err(serr, HTTP_INTERNAL_SERVER_ERROR,
                                 "could not determine youngest revision", 
                                 repos->pool);
    }

  serr = svn_repos_fs_begin_txn_for_commit(&txn, repos->repos, rev,
                                           repos->username, NULL, 
                                           repos->pool);
  if (serr != NULL)
    {
      return dav_svn_convert_err(serr, HTTP_INTERNAL_SERVER_ERROR,
                                 "could not begin a transaction", 
                                 repos->pool);
    }

  serr = svn_fs_txn_name(ptxn_name, txn, pool);
  if (serr != NULL)
    {
      return dav_svn_convert_err(serr, HTTP_INTERNAL_SERVER_ERROR,
                                 "could not fetch transaction name", 
                                 repos->pool);
    }

  return NULL;
}