/*
 * wcroot_anchor.c :  wcroot and anchor functions
 *
 * ====================================================================
 *    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.
 * ====================================================================
 */


#include <stdlib.h>
#include <string.h>

#include "svn_types.h"
#include "svn_pools.h"
#include "svn_string.h"
#include "svn_dirent_uri.h"
#include "svn_error.h"
#include "svn_io.h"
#include "svn_private_config.h"

#include "wc.h"

#include "private/svn_wc_private.h"

/* ABOUT ANCHOR AND TARGET, AND svn_wc_get_actual_target2()

   THE GOAL

   Note the following actions, where X is the thing we wish to update,
   P is a directory whose repository URL is the parent of
   X's repository URL, N is directory whose repository URL is *not*
   the parent directory of X (including the case where N is not a
   versioned resource at all):

      1.  `svn up .' from inside X.
      2.  `svn up ...P/X' from anywhere.
      3.  `svn up ...N/X' from anywhere.

   For the purposes of the discussion, in the '...N/X' situation, X is
   said to be a "working copy (WC) root" directory.

   Now consider the four cases for X's type (file/dir) in the working
   copy vs. the repository:

      A.  dir in working copy, dir in repos.
      B.  dir in working copy, file in repos.
      C.  file in working copy, dir in repos.
      D.  file in working copy, file in repos.

   Here are the results we expect for each combination of the above:

      1A. Successfully update X.
      1B. Error (you don't want to remove your current working
          directory out from underneath the application).
      1C. N/A (you can't be "inside X" if X is a file).
      1D. N/A (you can't be "inside X" if X is a file).

      2A. Successfully update X.
      2B. Successfully update X.
      2C. Successfully update X.
      2D. Successfully update X.

      3A. Successfully update X.
      3B. Error (you can't create a versioned file X inside a
          non-versioned directory).
      3C. N/A (you can't have a versioned file X in directory that is
          not its repository parent).
      3D. N/A (you can't have a versioned file X in directory that is
          not its repository parent).

   To summarize, case 2 always succeeds, and cases 1 and 3 always fail
   (or can't occur) *except* when the target is a dir that remains a
   dir after the update.

   ACCOMPLISHING THE GOAL

   Updates are accomplished by driving an editor, and an editor is
   "rooted" on a directory.  So, in order to update a file, we need to
   break off the basename of the file, rooting the editor in that
   file's parent directory, and then updating only that file, not the
   other stuff in its parent directory.

   Secondly, we look at the case where we wish to update a directory.
   This is typically trivial.  However, one problematic case, exists
   when we wish to update a directory that has been removed from the
   repository and replaced with a file of the same name.  If we root
   our edit at the initial directory, there is no editor mechanism for
   deleting that directory and replacing it with a file (this would be
   like having an editor now anchored on a file, which is disallowed).

   All that remains is to have a function with the knowledge required
   to properly decide where to root our editor, and what to act upon
   with that now-rooted editor.  Given a path to be updated, this
   function should conditionally split that path into an "anchor" and
   a "target", where the "anchor" is the directory at which the update
   editor is rooted (meaning, editor->open_root() is called with
   this directory in mind), and the "target" is the actual intended
   subject of the update.

   svn_wc_get_actual_target2() is that function.

   So, what are the conditions?

   Case I: Any time X is '.' (implying it is a directory), we won't
   lop off a basename.  So we'll root our editor at X, and update all
   of X.

   Cases II & III: Any time we are trying to update some path ...N/X,
   we again will not lop off a basename.  We can't root an editor at
   ...N with X as a target, either because ...N isn't a versioned
   resource at all (Case II) or because X is X is not a child of ...N
   in the repository (Case III).  We root at X, and update X.

   Cases IV-???: We lop off a basename when we are updating a
   path ...P/X, rooting our editor at ...P and updating X, or when X
   is missing from disk.

   These conditions apply whether X is a file or directory.

   ---

   As it turns out, commits need to have a similar check in place,
   too, specifically for the case where a single directory is being
   committed (we have to anchor at that directory's parent in case the
   directory itself needs to be modified).
*/


svn_error_t *
svn_wc_check_root(svn_boolean_t *is_wcroot,
                  svn_boolean_t *is_switched,
                  svn_node_kind_t *kind,
                  svn_wc_context_t *wc_ctx,
                  const char *local_abspath,
                  apr_pool_t *scratch_pool)
{
  SVN_ERR_ASSERT(svn_dirent_is_absolute(local_abspath));

  return svn_error_trace(svn_wc__db_is_switched(is_wcroot,is_switched, kind,
                                                wc_ctx->db, local_abspath,
                                                scratch_pool));
}

svn_error_t *
svn_wc__is_wcroot(svn_boolean_t *is_wcroot,
                  svn_wc_context_t *wc_ctx,
                  const char *local_abspath,
                  apr_pool_t *scratch_pool)
{
  return svn_error_trace(svn_wc__db_is_wcroot(is_wcroot,
                                              wc_ctx->db,
                                              local_abspath,
                                              scratch_pool));
}


svn_error_t *
svn_wc__get_wcroot(const char **wcroot_abspath,
                   svn_wc_context_t *wc_ctx,
                   const char *local_abspath,
                   apr_pool_t *result_pool,
                   apr_pool_t *scratch_pool)
{
  return svn_wc__db_get_wcroot(wcroot_abspath, wc_ctx->db,
                               local_abspath, result_pool, scratch_pool);
}


svn_error_t *
svn_wc__get_experimental_dir(char **dir,
                             svn_wc_context_t *wc_ctx,
                             const char *local_abspath,
                             apr_pool_t *result_pool,
                             apr_pool_t *scratch_pool)
{
  const char *wcroot_abspath;

  SVN_ERR(svn_wc__get_wcroot(&wcroot_abspath, wc_ctx, local_abspath,
                             scratch_pool, scratch_pool));
  *dir = svn_dirent_join(wcroot_abspath,
                         SVN_WC_ADM_DIR_NAME "/" SVN_WC__ADM_EXPERIMENTAL,
                         result_pool);

  /* Ensure the directory exists. (Other versions of svn don't create it.) */
  SVN_ERR(svn_io_make_dir_recursively(*dir, scratch_pool));

  return SVN_NO_ERROR;
}


svn_error_t *
svn_wc_get_actual_target2(const char **anchor,
                          const char **target,
                          svn_wc_context_t *wc_ctx,
                          const char *path,
                          apr_pool_t *result_pool,
                          apr_pool_t *scratch_pool)
{
  svn_boolean_t is_wc_root, is_switched;
  svn_node_kind_t kind;
  const char *local_abspath;
  svn_error_t *err;

  SVN_ERR(svn_dirent_get_absolute(&local_abspath, path, scratch_pool));

  err = svn_wc__db_is_switched(&is_wc_root, &is_switched, &kind,
                               wc_ctx->db, local_abspath,
                               scratch_pool);

  if (err)
    {
      if (err->apr_err != SVN_ERR_WC_PATH_NOT_FOUND &&
          err->apr_err != SVN_ERR_WC_NOT_WORKING_COPY)
        return svn_error_trace(err);

      svn_error_clear(err);
      is_wc_root = FALSE;
      is_switched = FALSE;
    }

  /* If PATH is not a WC root, or if it is a file, lop off a basename. */
  if (!(is_wc_root || is_switched) || (kind != svn_node_dir))
    {
      svn_dirent_split(anchor, target, path, result_pool);
    }
  else
    {
      *anchor = apr_pstrdup(result_pool, path);
      *target = "";
    }

  return SVN_NO_ERROR;
}