tree.c

subversion-1.4.3-1.tar.gz 配置svn的源码

/* Determine if the properties of two path/root combinations are
   different.  Set *CHANGED_P to TRUE if the properties at PATH1 under
   ROOT1 differ from those at PATH2 under ROOT2, or FALSE otherwise.
   Both roots must be in the same filesystem. */
static svn_error_t *
fs_props_changed(svn_boolean_t *changed_p,
                 svn_fs_root_t *root1,
                 const char *path1,
                 svn_fs_root_t *root2,
                 const char *path2,
                 apr_pool_t *pool)
{
  dag_node_t *node1, *node2;
  
  /* Check that roots are in the same fs. */
  if (root1->fs != root2->fs)
    return svn_error_create
      (SVN_ERR_FS_GENERAL, NULL,
       _("Cannot compare property value between two different filesystems"));
  
  SVN_ERR(get_dag(&node1, root1, path1, pool));
  SVN_ERR(get_dag(&node2, root2, path2, pool));
  SVN_ERR(svn_fs_fs__things_different(changed_p, NULL, 
                                      node1, node2, pool));
  
  return SVN_NO_ERROR;
}



/* Merges and commits. */

/* Set ARGS->node to the root node of ARGS->root.  */
static svn_error_t *
get_root(dag_node_t **node, svn_fs_root_t *root, apr_pool_t *pool)
{
  SVN_ERR(get_dag(node, root, "", pool));
  return SVN_NO_ERROR;
}


static svn_error_t *
update_ancestry(svn_fs_t *fs,
                const svn_fs_id_t *source_id,
                const svn_fs_id_t *target_id,
                const char *txn_id,
                const char *target_path,
                int source_pred_count,
                apr_pool_t *pool)
{
  node_revision_t *noderev;

  if (svn_fs_fs__id_txn_id(target_id) == NULL)
    return svn_error_createf
      (SVN_ERR_FS_NOT_MUTABLE, NULL,
       _("Unexpected immutable node at '%s'"), target_path);

  SVN_ERR(svn_fs_fs__get_node_revision(&noderev, fs, target_id, pool));
  noderev->predecessor_id = source_id;
  noderev->predecessor_count = source_pred_count;
  if (noderev->predecessor_count != -1)
    noderev->predecessor_count++;
  SVN_ERR(svn_fs_fs__put_node_revision(fs, target_id, noderev, pool));

  return SVN_NO_ERROR;
}


/* Set the contents of CONFLICT_PATH to PATH, and return an
   SVN_ERR_FS_CONFLICT error that indicates that there was a conflict
   at PATH.  Perform all allocations in POOL (except the allocation of
   CONFLICT_PATH, which should be handled outside this function).  */
static svn_error_t *
conflict_err(svn_stringbuf_t *conflict_path,
             const char *path)
{
  svn_stringbuf_set(conflict_path, path);
  return svn_error_createf(SVN_ERR_FS_CONFLICT, NULL,
                           _("Conflict at '%s'"), path);
}


/* Merge changes between ANCESTOR and SOURCE into TARGET.  ANCESTOR
 * and TARGET must be distinct node revisions.  TARGET_PATH should
 * correspond to TARGET's full path in its filesystem, and is used for
 * reporting conflict location.
 *
 * SOURCE, TARGET, and ANCESTOR are generally directories; this
 * function recursively merges the directories' contents.  If any are
 * files, this function simply returns an error whenever SOURCE,
 * TARGET, and ANCESTOR are all distinct node revisions.
 *
 * If there are differences between ANCESTOR and SOURCE that conflict
 * with changes between ANCESTOR and TARGET, this function returns an
 * SVN_ERR_FS_CONFLICT error, and updates CONFLICT_P to the name of the
 * conflicting node in TARGET, with TARGET_PATH prepended as a path.
 *
 * If there are no conflicting differences, CONFLICT_P is updated to
 * the empty string.
 *
 * CONFLICT_P must point to a valid svn_stringbuf_t.
 *
 * Do any necessary temporary allocation in POOL.
 */
static svn_error_t *
merge(svn_stringbuf_t *conflict_p,
      const char *target_path,
      dag_node_t *target,
      dag_node_t *source,
      dag_node_t *ancestor,
      const char *txn_id,
      apr_pool_t *pool)
{
  const svn_fs_id_t *source_id, *target_id, *ancestor_id;
  apr_hash_t *s_entries, *t_entries, *a_entries;
  apr_hash_index_t *hi;
  svn_fs_t *fs;
  apr_pool_t *iterpool;
  int pred_count;

  /* Make sure everyone comes from the same filesystem. */
  fs = svn_fs_fs__dag_get_fs(ancestor);
  if ((fs != svn_fs_fs__dag_get_fs(source))
      || (fs != svn_fs_fs__dag_get_fs(target)))
    {
      return svn_error_create
        (SVN_ERR_FS_CORRUPT, NULL,
         _("Bad merge; ancestor, source, and target not all in same fs"));
    }

  /* We have the same fs, now check it. */
  SVN_ERR(svn_fs_fs__check_fs(fs));

  source_id   = svn_fs_fs__dag_get_id(source);
  target_id   = svn_fs_fs__dag_get_id(target);
  ancestor_id = svn_fs_fs__dag_get_id(ancestor);

  /* It's improper to call this function with ancestor == target. */
  if (svn_fs_fs__id_eq(ancestor_id, target_id))
    {
      svn_string_t *id_str = svn_fs_fs__id_unparse(target_id, pool);
      return svn_error_createf
        (SVN_ERR_FS_GENERAL, NULL,
         _("Bad merge; target '%s' has id '%s', same as ancestor"),
         target_path, id_str->data);
    }

  svn_stringbuf_setempty(conflict_p);

  /* Base cases:
   * Either no change made in source, or same change as made in target.
   * Both mean nothing to merge here.
   */
  if (svn_fs_fs__id_eq(ancestor_id, source_id)
      || (svn_fs_fs__id_eq(source_id, target_id)))
    return SVN_NO_ERROR;

  /* Else proceed, knowing all three are distinct node revisions.
   *
   * How to merge from this point: 
   *
   * if (not all 3 are directories)
   *   {
   *     early exit with conflict;
   *   }
   *
   * // Property changes may only be made to up-to-date
   * // directories, because once the client commits the prop
   * // change, it bumps the directory's revision, and therefore
   * // must be able to depend on there being no other changes to
   * // that directory in the repository.
   * if (target's property list differs from ancestor's)
   *    conflict;
   *
   * For each entry NAME in the directory ANCESTOR:
   *
   *   Let ANCESTOR-ENTRY, SOURCE-ENTRY, and TARGET-ENTRY be the IDs of
   *   the name within ANCESTOR, SOURCE, and TARGET respectively.
   *   (Possibly null if NAME does not exist in SOURCE or TARGET.)
   *
   *   If ANCESTOR-ENTRY == SOURCE-ENTRY, then:
   *     No changes were made to this entry while the transaction was in
   *     progress, so do nothing to the target.
   *
   *   Else if ANCESTOR-ENTRY == TARGET-ENTRY, then:
   *     A change was made to this entry while the transaction was in
   *     process, but the transaction did not touch this entry.  Replace
   *     TARGET-ENTRY with SOURCE-ENTRY.
   *
   *   Else:
   *     Changes were made to this entry both within the transaction and
   *     to the repository while the transaction was in progress.  They
   *     must be merged or declared to be in conflict.
   *
   *     If SOURCE-ENTRY and TARGET-ENTRY are both null, that's a
   *     double delete; flag a conflict.
   *
   *     If any of the three entries is of type file, declare a conflict.
   *
   *     If either SOURCE-ENTRY or TARGET-ENTRY is not a direct
   *     modification of ANCESTOR-ENTRY (determine by comparing the
   *     node-id fields), declare a conflict.  A replacement is
   *     incompatible with a modification or other replacement--even
   *     an identical replacement.
   *
   *     Direct modifications were made to the directory ANCESTOR-ENTRY
   *     in both SOURCE and TARGET.  Recursively merge these
   *     modifications.
   *
   * For each leftover entry NAME in the directory SOURCE:
   *
   *   If NAME exists in TARGET, declare a conflict.  Even if SOURCE and
   *   TARGET are adding exactly the same thing, two additions are not
   *   auto-mergeable with each other.
   *
   *   Add NAME to TARGET with the entry from SOURCE.
   *
   * Now that we are done merging the changes from SOURCE into the
   * directory TARGET, update TARGET's predecessor to be SOURCE.
   */

  if ((svn_fs_fs__dag_node_kind(source) != svn_node_dir)
      || (svn_fs_fs__dag_node_kind(target) != svn_node_dir)
      || (svn_fs_fs__dag_node_kind(ancestor) != svn_node_dir))
    {
      return conflict_err(conflict_p, target_path);
    }

      
  /* Possible early merge failure: if target and ancestor have
     different property lists, then the merge should fail.
     Propchanges can *only* be committed on an up-to-date directory.

     ### TODO: Please see issue #418 about the inelegance of this. */
  {
    node_revision_t *tgt_nr, *anc_nr;

    /* Get node revisions for our id's. */
    
    SVN_ERR(svn_fs_fs__get_node_revision(&tgt_nr, fs, target_id, pool));
    SVN_ERR(svn_fs_fs__get_node_revision(&anc_nr, fs, ancestor_id, pool));
    
    /* Now compare the prop-keys of the skels.  Note that just because
       the keys are different -doesn't- mean the proplists have
       different contents.  But merge() isn't concerned with contents;
       it doesn't do a brute-force comparison on textual contents, so
       it won't do that here either.  Checking to see if the propkey
       atoms are `equal' is enough. */
    if (! svn_fs_fs__noderev_same_rep_key(tgt_nr->prop_rep, anc_nr->prop_rep))
      {
        return conflict_err(conflict_p, target_path);
      }
  }

  /* ### todo: it would be more efficient to simply check for a NULL
     entries hash where necessary below than to allocate an empty hash
     here, but another day, another day... */
  SVN_ERR(svn_fs_fs__dag_dir_entries(&s_entries, source, pool));
  s_entries = svn_fs_fs__copy_dir_entries(s_entries, pool);
  SVN_ERR(svn_fs_fs__dag_dir_entries(&t_entries, target, pool));
  t_entries = svn_fs_fs__copy_dir_entries(t_entries, pool);
  SVN_ERR(svn_fs_fs__dag_dir_entries(&a_entries, ancestor, pool));
  a_entries = svn_fs_fs__copy_dir_entries(a_entries, pool);

  /* for each entry E in a_entries... */
  iterpool = svn_pool_create(pool);
  for (hi = apr_hash_first(pool, a_entries); 
       hi; 
       hi = apr_hash_next(hi))
    {
      svn_fs_dirent_t *s_entry, *t_entry, *a_entry;

      const void *key;
      void *val;
      apr_ssize_t klen;
          
      svn_pool_clear(iterpool);

      /* KEY will be the entry name in ancestor, VAL the dirent */
      apr_hash_this(hi, &key, &klen, &val);
      a_entry = val;

      s_entry = apr_hash_get(s_entries, key, klen);
      t_entry = apr_hash_get(t_entries, key, klen);

      /* No changes were made to this entry while the transaction was
         in progress, so do nothing to the target. */
      if (s_entry && svn_fs_fs__id_eq(a_entry->id, s_entry->id))
        goto end;

      /* A change was made to this entry while the transaction was in
         process, but the transaction did not touch this entry. */
      else if (t_entry && svn_fs_fs__id_eq(a_entry->id, t_entry->id))
        {
          if (s_entry)
            {
              SVN_ERR(svn_fs_fs__dag_set_entry(target, key,
                                               s_entry->id,
                                               s_entry->kind,
                                               txn_id,
                                               iterpool));
            }
          else
            {
              SVN_ERR(svn_fs_fs__dag_delete(target, key, txn_id, iterpool));
            }
        }

      /* Changes were made to this entry both within the transaction
         and to the repository while the transaction was in progress.
         They must be merged or declared to be in conflict. */
      else
        {
          dag_node_t *s_ent_node, *t_ent_node, *a_ent_node;
          const char *new_tpath;

          /* If SOURCE-ENTRY and TARGET-ENTRY are both null, that's a
             double delete; flag a conflict. */
          if (s_entry == NULL || t_entry == NULL)
            return conflict_err(conflict_p,
                                svn_path_join(target_path,
                                              a_entry->name,
                                              iterpool));

          /* If any of the three entries is of type file, flag a conflict. */
          if (s_entry->kind == svn_node_file
              || t_entry->kind == svn_node_file
              || a_entry->kind == svn_node_file)
            return conflict_err(conflict_p,
                                svn_path_join(target_path,
                                              a_entry->name,
                                              iterpool));

          /* If either SOURCE-ENTRY or TARGET-ENTRY is not a direct
             modification of ANCESTOR-ENTRY, declare a conflict. */
          if (strcmp(svn_fs_fs__id_node_id(s_entry->id),
                     svn_fs_fs__id_node_id(a_entry->id)) != 0
              || strcmp(svn_fs_fs__id_copy_id(s_entry->id),
                        svn_fs_fs__id_copy_id(a_entry->id)) != 0
              || strcmp(svn_fs_fs__id_node_id(t_entry->id),
                        svn_fs_fs__id_node_id(a_entry->id)) != 0
              || strcmp(svn_fs_fs__id_copy_id(t_entry->id),
                        svn_fs_fs__id_copy_id(a_entry->id)) != 0)
            return conflict_err(conflict_p,
                                svn_path_join(target_path,
                                              a_entry->name,
                                              iterpool));

          /* Direct modifications were made to the directory
             ANCESTOR-ENTRY in both SOURCE and TARGET.  Recursively
             merge these modifications. */
          SVN_ERR(svn_fs_fs__dag_get_node(&s_ent_node, fs,
                                          s_entry->id, iterpool));
          SVN_ERR(svn_fs_fs__dag_get_node(&t_ent_node, fs,
                                          t_entry->id, iterpool));
          SVN_ERR(svn_fs_fs__dag_get_node(&a_ent_node, fs,
                                          a_entry->id, iterpool));
          new_tpath = svn_path_join(target_path, t_entry->name, iterpool);
          SVN_ERR(merge(conflict_p, new_tpath,
                        t_ent_node, s_ent_node, a_ent_node,
                        txn_id, iterpool));
        }

      /* We've taken care of any possible implications E could have.
         Remove it from source_entries, so it's easy later to loop
         over all the source entries that didn't exist in
         ancestor_entries. */
    end:
      apr_hash_set(s_entries, key, klen, NULL);
    }

  /* For each entry E in source but not in ancestor */
  for (hi = apr_hash_first(pool, s_entries); 
       hi; 
       hi = apr_hash_next(hi))
    {