path: root/subversion/svnrdump/load_editor.c

/*
 *  load_editor.c: The svn_delta_editor_t editor used by svnrdump to
 *  load revisions.
 *
 * ====================================================================
 *    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 "svn_cmdline.h"
#include "svn_pools.h"
#include "svn_delta.h"
#include "svn_repos.h"
#include "svn_props.h"
#include "svn_path.h"
#include "svn_ra.h"
#include "svn_subst.h"
#include "svn_io.h"
#include "svn_private_config.h"
#include "private/svn_repos_private.h"
#include "private/svn_ra_private.h"
#include "private/svn_mergeinfo_private.h"
#include "private/svn_fspath.h"

#include "svnrdump.h"

#define SVNRDUMP_PROP_LOCK SVN_PROP_PREFIX "rdump-lock"

#define ARE_VALID_COPY_ARGS(p,r) ((p) && SVN_IS_VALID_REVNUM(r))


/**
 * A vtable that is driven by get_dumpstream_loader().
 */
typedef struct loader_fns_t
{
  /* Callback on starting a revision, to obtain an editor for the revision.
   *
   * This callback returns in *EDITOR and *EDIT_BATON an editor through which
   * its caller will drive the changes for revision REVISION.
   *
   * This callback should call the editor's SET_TARGET_REVISION method if
   * required.
   *
   * REV_PROPS holds the revision properties.
   *
   * POOL (and REV_PROPS) will persist until after the REVFINISH callback
   * returns.
   *
   * Modelled on svn_ra_replay_revstart_callback_t.
   */
  svn_error_t *(*revstart)(
    svn_revnum_t revision,
    void *baton,
    const svn_delta_editor_t **editor,
    void **edit_baton,
    apr_hash_t *rev_props,
    apr_pool_t *pool);

  /* Fetch the node props for ORIG_PATH @ ORIG_REV, a node of kind KIND.
   *
   * This callback is required if a non-deltas-format dump is parsed;
   * otherwise it will not be called and may be null. If required and not
   * provided, the loader will return SVN_ERR_UNSUPPORTED_FEATURE.
   *
   * Only regular props are needed. Any special kinds of property such as
   * entry-props and DAV/WC-props will be ignored.
   */
  svn_error_t *(*fetch_props)(
    apr_hash_t **props,
    void *baton,
    const char *orig_path,
    svn_revnum_t orig_rev,
    svn_node_kind_t kind,
    apr_pool_t *result_pool,
    apr_pool_t *scratch_pool);

} loader_fns_t;

/**
 * General baton used by the parser functions.
 */
struct parse_baton
{
  /* RA session(s) for committing to the target repository. */
  svn_ra_session_t *session;
  svn_ra_session_t *aux_session;

  /* To bleep, or not to bleep?  (What kind of question is that?) */
  svn_boolean_t quiet;

  /* Root URL of the target repository. */
  const char *root_url;

  /* The "parent directory" of the target repository in which to load.
     (This is essentially the difference between ROOT_URL and
     SESSION's url, and roughly equivalent to the 'svnadmin load
     --parent-dir' option.) */
  const char *parent_dir;

  /* A mapping of svn_revnum_t * dump stream revisions to their
     corresponding svn_revnum_t * target repository revisions. */
  /* ### See https://issues.apache.org/jira/browse/SVN-3903
     ### for discussion about improving the memory costs of this mapping. */
  apr_hash_t *rev_map;

  /* The most recent (youngest) revision from the dump stream mapped in
     REV_MAP, or SVN_INVALID_REVNUM if no revisions have been mapped. */
  svn_revnum_t last_rev_mapped;

  /* The oldest revision loaded from the dump stream, or
     SVN_INVALID_REVNUM if none have been loaded. */
  svn_revnum_t oldest_dumpstream_rev;

  /* An hash containing specific revision properties to skip while
     loading. */
  apr_hash_t *skip_revprops;

  const loader_fns_t *callbacks;
  void *cb_baton;
};

/**
 * Use to wrap the dir_context_t in commit.c so we can keep track of
 * relpath and parent for open_directory and close_directory.
 */
struct directory_baton
{
  void *baton;
  const char *relpath;

  /* The copy-from source of this directory, no matter whether it is
     copied explicitly (the root node of a copy) or implicitly (being an
     existing child of a copied directory). For a node that is newly
     added (without history), even inside a copied parent, these are
     NULL and SVN_INVALID_REVNUM. */
  const char *copyfrom_path;
  svn_revnum_t copyfrom_rev;

  struct directory_baton *parent;
};

/**
 * Baton used to represent a node; to be used by the parser
 * functions. Contains a link to the revision baton.
 */
struct node_baton
{
  const char *path;
  svn_node_kind_t kind;
  enum svn_node_action action;

  /* Is this directory explicitly added? If not, then it already existed
     or is a child of a copy. */
  svn_boolean_t is_added;

  svn_revnum_t copyfrom_rev;
  const char *copyfrom_path;
  const char *copyfrom_url;

  void *file_baton;
  const char *base_checksum;

  /* (const char *name) -> (svn_prop_t *) */
  apr_hash_t *prop_changes;

  struct revision_baton *rb;
};

/**
 * Baton used to represet a revision; used by the parser
 * functions. Contains a link to the parser baton.
 */
struct revision_baton
{
  svn_revnum_t rev;
  apr_hash_t *revprop_table;
  svn_revnum_t head_rev_before_commit;
  apr_int32_t rev_offset;

  /* Commit editor and baton used to transfer loaded revisions to
     the target repository. */
  const svn_delta_editor_t *commit_editor;
  void *commit_edit_baton;

  const svn_string_t *datestamp;
  const svn_string_t *author;

  struct parse_baton *pb;
  struct directory_baton *db;
  apr_pool_t *pool;
};



/* Record the mapping of FROM_REV to TO_REV in REV_MAP, ensuring that
   anything added to the hash is allocated in the hash's pool. */
static void
set_revision_mapping(apr_hash_t *rev_map,
                     svn_revnum_t from_rev,
                     svn_revnum_t to_rev)
{
  svn_revnum_t *mapped_revs = apr_palloc(apr_hash_pool_get(rev_map),
                                         sizeof(svn_revnum_t) * 2);
  mapped_revs[0] = from_rev;
  mapped_revs[1] = to_rev;
  apr_hash_set(rev_map, mapped_revs, sizeof(*mapped_revs), mapped_revs + 1);
}

/* Return the revision to which FROM_REV maps in REV_MAP, or
   SVN_INVALID_REVNUM if no such mapping exists. */
static svn_revnum_t
get_revision_mapping(apr_hash_t *rev_map,
                     svn_revnum_t from_rev)
{
  svn_revnum_t *to_rev = apr_hash_get(rev_map, &from_rev,
                                      sizeof(from_rev));
  return to_rev ? *to_rev : SVN_INVALID_REVNUM;
}


static svn_error_t *
magic_header_record(int version,
            void *parse_baton,
            apr_pool_t *pool)
{
  return SVN_NO_ERROR;
}

static svn_error_t *
uuid_record(const char *uuid,
            void *parse_baton,
            apr_pool_t *pool)
{
  return SVN_NO_ERROR;
}

/* Push information about another directory onto the linked list RB->db.
 *
 * CHILD_BATON is the baton returned by the commit editor. RELPATH is the
 * repository-relative path of this directory. IS_ADDED is true iff this
 * directory is being added (with or without history). If added with
 * history then COPYFROM_PATH/COPYFROM_REV are the copyfrom source, else
 * are NULL/SVN_INVALID_REVNUM.
 */
static void
push_directory(struct revision_baton *rb,
               void *child_baton,
               const char *relpath,
               svn_boolean_t is_added,
               const char *copyfrom_path,
               svn_revnum_t copyfrom_rev)
{
  struct directory_baton *child_db = apr_pcalloc(rb->pool, sizeof (*child_db));

  SVN_ERR_ASSERT_NO_RETURN(
    is_added || (copyfrom_path == NULL && copyfrom_rev == SVN_INVALID_REVNUM));

  /* If this node is an existing (not newly added) child of a copied node,
     calculate where it was copied from. */
  if (!is_added
      && ARE_VALID_COPY_ARGS(rb->db->copyfrom_path, rb->db->copyfrom_rev))
    {
      const char *name = svn_relpath_basename(relpath, NULL);

      copyfrom_path = svn_relpath_join(rb->db->copyfrom_path, name,
                                       rb->pool);
      copyfrom_rev = rb->db->copyfrom_rev;
    }

  child_db->baton = child_baton;
  child_db->relpath = relpath;
  child_db->copyfrom_path = copyfrom_path;
  child_db->copyfrom_rev = copyfrom_rev;
  child_db->parent = rb->db;
  rb->db = child_db;
}

/* Called to obtain an editor for the revision described by RB.
 */
static svn_error_t *
revision_start_edit(struct revision_baton *rb,
                    apr_pool_t *scratch_pool)
{
  struct parse_baton *pb = rb->pb;
  void *child_baton;

  SVN_ERR(pb->callbacks->revstart(rb->rev,
                                  pb->cb_baton,
                                  &rb->commit_editor, &rb->commit_edit_baton,
                                  rb->revprop_table,
                                  rb->pool));
  SVN_ERR(rb->commit_editor->open_root(rb->commit_edit_baton,
                                       rb->head_rev_before_commit,
                                       rb->pool, &child_baton));
  /* child_baton corresponds to the root directory baton here */
  push_directory(rb, child_baton, "", TRUE /*is_added*/,
                 NULL, SVN_INVALID_REVNUM);
  return SVN_NO_ERROR;
}

static svn_error_t *
new_revision_record(void **revision_baton,
                    apr_hash_t *headers,
                    void *parse_baton,
                    apr_pool_t *pool)
{
  struct parse_baton *pb = parse_baton;
  struct revision_baton *rb;
  const char *rev_str;

  rb = apr_pcalloc(pool, sizeof(*rb));
  rb->pool = svn_pool_create(pool);
  rb->pb = pb;
  rb->db = NULL;

  rev_str = svn_hash_gets(headers, SVN_REPOS_DUMPFILE_REVISION_NUMBER);
  if (rev_str)
    rb->rev = SVN_STR_TO_REV(rev_str);

  SVN_ERR(svn_ra_get_latest_revnum(pb->session, &rb->head_rev_before_commit,
                                   pool));

  /* FIXME: This is a lame fallback loading multiple segments of dump in
     several separate operations. It is highly susceptible to race conditions.
     Calculate the revision 'offset' for finding copyfrom sources.
     It might be positive or negative. */
  rb->rev_offset = (apr_int32_t) ((rb->rev) - (rb->head_rev_before_commit + 1));

  /* Stash the oldest (non-zero) dumpstream revision seen. */
  if ((rb->rev > 0) && (!SVN_IS_VALID_REVNUM(pb->oldest_dumpstream_rev)))
    pb->oldest_dumpstream_rev = rb->rev;

  /* Set the commit_editor/ commit_edit_baton to NULL and wait for
     them to be created in new_node_record */
  rb->commit_editor = NULL;
  rb->commit_edit_baton = NULL;
  rb->revprop_table = apr_hash_make(rb->pool);

  *revision_baton = rb;
  return SVN_NO_ERROR;
}

static svn_error_t *
new_node_record(void **node_baton,
                apr_hash_t *headers,
                void *revision_baton,
                apr_pool_t *pool)
{
  struct revision_baton *rb = revision_baton;
  const struct svn_delta_editor_t *commit_editor = rb->commit_editor;
  struct node_baton *nb;
  apr_hash_index_t *hi;
  void *child_baton;
  const char *nb_dirname;

  nb = apr_pcalloc(rb->pool, sizeof(*nb));
  nb->rb = rb;
  nb->is_added = FALSE;
  nb->copyfrom_path = NULL;
  nb->copyfrom_url = NULL;
  nb->copyfrom_rev = SVN_INVALID_REVNUM;
  nb->prop_changes = apr_hash_make(rb->pool);

  /* If the creation of commit_editor is pending, create it now and
     open_root on it; also create a top-level directory baton. */
  if (!commit_editor)
    {
      /* The revprop_table should have been filled in with important
         information like svn:log in set_revision_property. We can now
         use it all this information to create our commit_editor. But
         first, clear revprops that we aren't allowed to set with the
         commit_editor. We'll set them separately using the RA API
         after closing the editor (see close_revision). */

      svn_hash_sets(rb->revprop_table, SVN_PROP_REVISION_AUTHOR, NULL);
      svn_hash_sets(rb->revprop_table, SVN_PROP_REVISION_DATE, NULL);

      SVN_ERR(revision_start_edit(rb, pool));
      commit_editor = rb->commit_editor;
    }

  for (hi = apr_hash_first(rb->pool, headers); hi; hi = apr_hash_next(hi))
    {
      const char *hname = apr_hash_this_key(hi);
      const char *hval = apr_hash_this_val(hi);

      /* Parse the different kinds of headers we can encounter and
         stuff them into the node_baton for writing later */
      if (strcmp(hname, SVN_REPOS_DUMPFILE_NODE_PATH) == 0)
        nb->path = apr_pstrdup(rb->pool, hval);
      if (strcmp(hname, SVN_REPOS_DUMPFILE_NODE_KIND) == 0)
        nb->kind = strcmp(hval, "file") == 0 ? svn_node_file : svn_node_dir;
      if (strcmp(hname, SVN_REPOS_DUMPFILE_NODE_ACTION) == 0)
        {
          if (strcmp(hval, "add") == 0)
            nb->action = svn_node_action_add;
          if (strcmp(hval, "change") == 0)
            nb->action = svn_node_action_change;
          if (strcmp(hval, "delete") == 0)
            nb->action = svn_node_action_delete;
          if (strcmp(hval, "replace") == 0)
            nb->action = svn_node_action_replace;
        }
      if (strcmp(hname, SVN_REPOS_DUMPFILE_TEXT_DELTA_BASE_MD5) == 0)
        nb->base_checksum = apr_pstrdup(rb->pool, hval);
      if (strcmp(hname, SVN_REPOS_DUMPFILE_NODE_COPYFROM_REV) == 0)
        nb->copyfrom_rev = SVN_STR_TO_REV(hval);
      if (strcmp(hname, SVN_REPOS_DUMPFILE_NODE_COPYFROM_PATH) == 0)
        nb->copyfrom_path = apr_pstrdup(rb->pool, hval);
    }

  /* Before handling the new node, ensure depth-first editing order by
     traversing the directory hierarchy from the old node's to the new
     node's parent directory. */
  nb_dirname = svn_relpath_dirname(nb->path, pool);
  if (svn_path_compare_paths(nb_dirname,
                             rb->db->relpath) != 0)
    {
      char *ancestor_path;
      apr_size_t residual_close_count;
      apr_array_header_t *residual_open_path;
      int i;
      apr_size_t n;

      ancestor_path =
        svn_relpath_get_longest_ancestor(nb_dirname,
                                         rb->db->relpath, pool);
      residual_close_count =
        svn_path_component_count(svn_relpath_skip_ancestor(ancestor_path,
                                                           rb->db->relpath));
      residual_open_path =
        svn_path_decompose(svn_relpath_skip_ancestor(ancestor_path,
                                                     nb_dirname), pool);

      /* First close all as many directories as there are after
         skip_ancestor, and then open fresh directories */
      for (n = 0; n < residual_close_count; n ++)
        {
          /* Don't worry about destroying the actual rb->db object,
             since the pool we're using has the lifetime of one
             revision anyway */
          SVN_ERR(commit_editor->close_directory(rb->db->baton, rb->pool));
          rb->db = rb->db->parent;
        }

      for (i = 0; i < residual_open_path->nelts; i ++)
        {
          char *relpath_compose =
            svn_relpath_join(rb->db->relpath,
                             APR_ARRAY_IDX(residual_open_path, i, const char *),
                             rb->pool);
          SVN_ERR(commit_editor->open_directory(relpath_compose,
                                                rb->db->baton,
                                                rb->head_rev_before_commit,
                                                rb->pool, &child_baton));
          push_directory(rb, child_baton, relpath_compose, TRUE /*is_added*/,
                         NULL, SVN_INVALID_REVNUM);
        }
    }

  /* Fix up the copyfrom information in light of mapped revisions and
     non-root load targets, and convert copyfrom path into a full
     URL. */
  if (nb->copyfrom_path && SVN_IS_VALID_REVNUM(nb->copyfrom_rev))
    {
      svn_revnum_t copyfrom_rev;

      /* Try to find the copyfrom revision in the revision map;
         failing that, fall back to the revision offset approach. */
      copyfrom_rev = get_revision_mapping(rb->pb->rev_map, nb->copyfrom_rev);
      if (! SVN_IS_VALID_REVNUM(copyfrom_rev))
        copyfrom_rev = nb->copyfrom_rev - rb->rev_offset;

      if (! SVN_IS_VALID_REVNUM(copyfrom_rev))
        return svn_error_createf(SVN_ERR_FS_NO_SUCH_REVISION, NULL,
                                 _("Relative source revision %ld is not"
                                   " available in current repository"),
                                 copyfrom_rev);

      nb->copyfrom_rev = copyfrom_rev;

      if (rb->pb->parent_dir)
        nb->copyfrom_path = svn_relpath_join(rb->pb->parent_dir,
                                             nb->copyfrom_path, rb->pool);
      /* Convert to a URL, as the commit editor requires. */
      nb->copyfrom_url = svn_path_url_add_component2(rb->pb->root_url,
                                                      nb->copyfrom_path,
                                                      rb->pool);
    }


  switch (nb->action)
    {
    case svn_node_action_delete:
    case svn_node_action_replace:
      SVN_ERR(commit_editor->delete_entry(nb->path,
                                          rb->head_rev_before_commit,
                                          rb->db->baton, rb->pool));
      if (nb->action == svn_node_action_delete)
        break;
      else
        /* FALL THROUGH */;
    case svn_node_action_add:
      nb->is_added = TRUE;
      switch (nb->kind)
        {
        case svn_node_file:
          SVN_ERR(commit_editor->add_file(nb->path, rb->db->baton,
                                          nb->copyfrom_url,
                                          nb->copyfrom_rev,
                                          rb->pool, &(nb->file_baton)));
          break;
        case svn_node_dir:
          SVN_ERR(commit_editor->add_directory(nb->path, rb->db->baton,
                                               nb->copyfrom_url,
                                               nb->copyfrom_rev,
                                               rb->pool, &child_baton));
          push_directory(rb, child_baton, nb->path, TRUE /*is_added*/,
                         nb->copyfrom_path, nb->copyfrom_rev);
          break;
        default:
          break;
        }
      break;
    case svn_node_action_change:
      switch (nb->kind)
        {
        case svn_node_file:
          SVN_ERR(commit_editor->open_file(nb->path, rb->db->baton,
                                           SVN_INVALID_REVNUM, rb->pool,
                                           &(nb->file_baton)));
          break;
        default:
          SVN_ERR(commit_editor->open_directory(nb->path, rb->db->baton,
                                                rb->head_rev_before_commit,
                                                rb->pool, &child_baton));
          push_directory(rb, child_baton, nb->path, FALSE /*is_added*/,
                         NULL, SVN_INVALID_REVNUM);
          break;
        }
      break;
    }

  *node_baton = nb;
  return SVN_NO_ERROR;
}

static svn_error_t *
set_revision_property(void *baton,
                      const char *name,
                      const svn_string_t *value)
{
  struct revision_baton *rb = baton;

  SVN_ERR(svn_repos__normalize_prop(&value, NULL, name, value,
                                    rb->pool, rb->pool));
  SVN_ERR(svn_repos__validate_prop(name, value, rb->pool));

  if (rb->rev > 0)
    {
      if (! svn_hash_gets(rb->pb->skip_revprops, name))
        svn_hash_sets(rb->revprop_table,
                      apr_pstrdup(rb->pool, name),
                      svn_string_dup(value, rb->pool));
    }
  else if (rb->head_rev_before_commit == 0
           && ! svn_hash_gets(rb->pb->skip_revprops, name))
    {
      /* Special case: set revision 0 properties directly (which is
         safe because the commit_editor hasn't been created yet), but
         only when loading into an 'empty' filesystem. */
      SVN_ERR(svn_ra_change_rev_prop2(rb->pb->session, 0,
                                      name, NULL, value, rb->pool));
    }

  /* Remember any datestamp/ author that passes through (see comment
     in close_revision). */
  if (!strcmp(name, SVN_PROP_REVISION_DATE))
    rb->datestamp = svn_string_dup(value, rb->pool);
  if (!strcmp(name, SVN_PROP_REVISION_AUTHOR))
    rb->author = svn_string_dup(value, rb->pool);

  return SVN_NO_ERROR;
}

static svn_error_t *
set_node_property(void *baton,
                  const char *name,
                  const svn_string_t *value)
{
  struct node_baton *nb = baton;
  struct revision_baton *rb = nb->rb;
  struct parse_baton *pb = rb->pb;
  apr_pool_t *pool = nb->rb->pool;
  svn_prop_t *prop;

  if (value && strcmp(name, SVN_PROP_MERGEINFO) == 0)
    {
      svn_string_t *new_value;
      svn_error_t *err;

      err = svn_repos__adjust_mergeinfo_property(&new_value, value,
                                                 pb->parent_dir,
                                                 pb->rev_map,
                                                 pb->oldest_dumpstream_rev,
                                                 rb->rev_offset,
                                                 NULL, NULL, /*notify*/
                                                 pool, pool);
      if (err)
        {
          return svn_error_quick_wrap(err,
                                      _("Invalid svn:mergeinfo value"));
        }

      value = new_value;
    }

  SVN_ERR(svn_repos__normalize_prop(&value, NULL, name, value, pool, pool));

  SVN_ERR(svn_repos__validate_prop(name, value, pool));

  prop = apr_palloc(nb->rb->pool, sizeof (*prop));
  prop->name = apr_pstrdup(pool, name);
  prop->value = svn_string_dup(value, pool);
  svn_hash_sets(nb->prop_changes, prop->name, prop);

  return SVN_NO_ERROR;
}

static svn_error_t *
delete_node_property(void *baton,
                     const char *name)
{
  struct node_baton *nb = baton;
  apr_pool_t *pool = nb->rb->pool;
  svn_prop_t *prop;

  SVN_ERR(svn_repos__validate_prop(name, NULL, pool));

  prop = apr_palloc(pool, sizeof (*prop));
  prop->name = apr_pstrdup(pool, name);
  prop->value = NULL;
  svn_hash_sets(nb->prop_changes, prop->name, prop);

  return SVN_NO_ERROR;
}

/* Delete all the properties of the node, if any.
 *
 * The commit editor doesn't have a method to delete a node's properties
 * without knowing what they are, so we have to first find out what
 * properties the node would have had. If it's copied (explicitly or
 * implicitly), we look at the copy source. If it's only being changed,
 * we look at the node's current path in the head revision.
 */
static svn_error_t *
remove_node_props(void *baton)
{
  struct node_baton *nb = baton;
  struct revision_baton *rb = nb->rb;
  apr_pool_t *pool = nb->rb->pool;
  apr_hash_index_t *hi;
  apr_hash_t *props;
  const char *orig_path;
  svn_revnum_t orig_rev;

  /* Find the path and revision that has the node's original properties */
  if (ARE_VALID_COPY_ARGS(nb->copyfrom_path, nb->copyfrom_rev))
    {
      orig_path = nb->copyfrom_path;
      orig_rev = nb->copyfrom_rev;
    }
  else if (!nb->is_added
           && ARE_VALID_COPY_ARGS(rb->db->copyfrom_path, rb->db->copyfrom_rev))
    {
      /* If this is a dir, then it's described by rb->db;
         if this is a file, then it's a child of the dir in rb->db. */
      orig_path = (nb->kind == svn_node_dir)
                    ? rb->db->copyfrom_path
                    : svn_relpath_join(rb->db->copyfrom_path,
                                       svn_relpath_basename(nb->path, NULL),
                                       rb->pool);
      orig_rev = rb->db->copyfrom_rev;
    }
  else
    {
      /* ### Should we query at a known, fixed, "head" revision number
         instead of passing SVN_INVALID_REVNUM and getting a moving target? */
      orig_path = nb->path;
      orig_rev = SVN_INVALID_REVNUM;
    }

  if ((nb->action == svn_node_action_add
            || nb->action == svn_node_action_replace)
      && ! ARE_VALID_COPY_ARGS(orig_path, orig_rev))
    /* Add-without-history; no "old" properties to worry about. */
    return SVN_NO_ERROR;

  if (! rb->pb->callbacks->fetch_props)
    return svn_error_create(SVN_ERR_UNSUPPORTED_FEATURE, NULL,
                            _("This dumpstream reader requires a delta "
                              "format dumpstream"));
  SVN_ERR(rb->pb->callbacks->fetch_props(&props,
                                         rb->pb->cb_baton,
                                         orig_path, orig_rev, nb->kind,
                                         pool, pool));

  for (hi = apr_hash_first(pool, props); hi; hi = apr_hash_next(hi))
    {
      const char *name = apr_hash_this_key(hi);
      svn_prop_kind_t kind = svn_property_kind2(name);

      if (kind == svn_prop_regular_kind)
        SVN_ERR(set_node_property(nb, name, NULL));
    }

  return SVN_NO_ERROR;
}

static svn_error_t *
set_fulltext(svn_stream_t **stream,
             void *node_baton)
{
  struct node_baton *nb = node_baton;
  const struct svn_delta_editor_t *commit_editor = nb->rb->commit_editor;
  svn_txdelta_window_handler_t handler;
  void *handler_baton;
  apr_pool_t *pool = nb->rb->pool;

  SVN_ERR(commit_editor->apply_textdelta(nb->file_baton, nb->base_checksum,
                                         pool, &handler, &handler_baton));
  *stream = svn_txdelta_target_push(handler, handler_baton,
                                    svn_stream_empty(pool), pool);
  return SVN_NO_ERROR;
}

static svn_error_t *
apply_textdelta(svn_txdelta_window_handler_t *handler,
                void **handler_baton,
                void *node_baton)
{
  struct node_baton *nb = node_baton;
  const struct svn_delta_editor_t *commit_editor = nb->rb->commit_editor;
  apr_pool_t *pool = nb->rb->pool;

  SVN_ERR(commit_editor->apply_textdelta(nb->file_baton, nb->base_checksum,
                                         pool, handler, handler_baton));

  return SVN_NO_ERROR;
}

static svn_error_t *
close_node(void *baton)
{
  struct node_baton *nb = baton;
  const struct svn_delta_editor_t *commit_editor = nb->rb->commit_editor;
  apr_pool_t *pool = nb->rb->pool;
  apr_hash_index_t *hi;

  for (hi = apr_hash_first(pool, nb->prop_changes);
       hi; hi = apr_hash_next(hi))
    {
      const char *name = apr_hash_this_key(hi);
      svn_prop_t *prop = apr_hash_this_val(hi);

      switch (nb->kind)
        {
        case svn_node_file:
          SVN_ERR(commit_editor->change_file_prop(nb->file_baton,
                                                  name, prop->value, pool));
          break;
        case svn_node_dir:
          SVN_ERR(commit_editor->change_dir_prop(nb->rb->db->baton,
                                                 name, prop->value, pool));
          break;
        default:
          break;
        }
    }

  /* Pass a file node closure through to the editor *unless* we
     deleted the file (which doesn't require us to open it). */
  if ((nb->kind == svn_node_file) && (nb->file_baton))
    {
      SVN_ERR(commit_editor->close_file(nb->file_baton, NULL, nb->rb->pool));
    }

  /* The svn_node_dir case is handled in close_revision */

  return SVN_NO_ERROR;
}

static svn_error_t *
close_revision(void *baton)
{
  struct revision_baton *rb = baton;
  const svn_delta_editor_t *commit_editor = rb->commit_editor;
  void *commit_edit_baton = rb->commit_edit_baton;
  svn_revnum_t committed_rev = SVN_INVALID_REVNUM;

  /* Fake revision 0 */
  if (rb->rev == 0)
    {
      /* ### Don't print directly; generate a notification. */
      if (! rb->pb->quiet)
        SVN_ERR(svn_cmdline_printf(rb->pool, "* Loaded revision 0.\n"));
    }
  else if (commit_editor)
    {
      /* Close all pending open directories, and then close the edit
         session itself */
      while (rb->db && rb->db->parent)
        {
          SVN_ERR(commit_editor->close_directory(rb->db->baton, rb->pool));
          rb->db = rb->db->parent;
        }
      /* root dir's baton */
      SVN_ERR(commit_editor->close_directory(rb->db->baton, rb->pool));
      SVN_ERR(commit_editor->close_edit(commit_edit_baton, rb->pool));
    }
  else
    {
      /* Legitimate revision with no node information */
      SVN_ERR(revision_start_edit(rb, rb->pool));
      commit_editor = rb->commit_editor;
      commit_edit_baton = rb->commit_edit_baton;

      SVN_ERR(commit_editor->close_directory(rb->db->baton, rb->pool));
      SVN_ERR(commit_editor->close_edit(commit_edit_baton, rb->pool));
    }

  /* svn_fs_commit_txn() rewrites the datestamp and author properties;
     we'll rewrite them again by hand after closing the commit_editor.
     The only time we don't do this is for revision 0 when loaded into
     a non-empty repository.  */
  if (rb->rev > 0)
    {
      committed_rev = get_revision_mapping(rb->pb->rev_map, rb->rev);
    }
  else if (rb->head_rev_before_commit == 0)
    {
      committed_rev = 0;
    }

  if (SVN_IS_VALID_REVNUM(committed_rev))
    {
      if (!svn_hash_gets(rb->pb->skip_revprops, SVN_PROP_REVISION_DATE))
        {
          SVN_ERR(svn_ra_change_rev_prop2(rb->pb->session, committed_rev,
                                          SVN_PROP_REVISION_DATE,
                                          NULL, rb->datestamp, rb->pool));
        }
      if (!svn_hash_gets(rb->pb->skip_revprops, SVN_PROP_REVISION_AUTHOR))
        {
          SVN_ERR(svn_ra_change_rev_prop2(rb->pb->session, committed_rev,
                                          SVN_PROP_REVISION_AUTHOR,
                                          NULL, rb->author, rb->pool));
        }
    }

  svn_pool_destroy(rb->pool);

  return SVN_NO_ERROR;
}

/*----------------------------------------------------------------------*/

/**
 * Baton used for commit callback (and Ev2 shims).
 */
struct commit_baton_t
{
  svn_revnum_t rev;
  struct parse_baton *pb;
};

/*
 * - Notification of the commit.
 * - Update the revision number mapping to take account of the actual
 *   committed revision number.
 */
static svn_error_t *
commit_callback(const svn_commit_info_t *commit_info,
                void *baton,
                apr_pool_t *pool)
{
  struct commit_baton_t *cb = baton;
  struct parse_baton *pb = cb->pb;

  /* ### Don't print directly; generate a notification. */
  if (! pb->quiet)
    SVN_ERR(svn_cmdline_printf(pool, "* Loaded revision %ld.\n",
                               commit_info->revision));

  /* Add the mapping of the dumpstream revision to the committed revision. */
  set_revision_mapping(pb->rev_map, cb->rev, commit_info->revision);

  /* If the incoming dump stream has non-contiguous revisions (e.g. from
     using svndumpfilter --drop-empty-revs without --renumber-revs) then
     we must account for the missing gaps in PB->REV_MAP.  Otherwise we
     might not be able to map all mergeinfo source revisions to the correct
     revisions in the target repos. */
  if ((pb->last_rev_mapped != SVN_INVALID_REVNUM)
      && (cb->rev != pb->last_rev_mapped + 1))
    {
      svn_revnum_t i;

      for (i = pb->last_rev_mapped + 1; i < cb->rev; i++)
        {
          set_revision_mapping(pb->rev_map, i, pb->last_rev_mapped);
        }
    }

  /* Update our "last revision mapped". */
  pb->last_rev_mapped = cb->rev;

  return SVN_NO_ERROR;
}

static svn_error_t *
fetch_base_func(const char **filename,
                void *baton,
                const char *path,
                svn_revnum_t base_revision,
                apr_pool_t *result_pool,
                apr_pool_t *scratch_pool)
{
  struct commit_baton_t *cb = baton;
  svn_stream_t *fstream;
  svn_error_t *err;

  if (! SVN_IS_VALID_REVNUM(base_revision))
    base_revision = cb->rev - 1;

  SVN_ERR(svn_stream_open_unique(&fstream, filename, NULL,
                                 svn_io_file_del_on_pool_cleanup,
                                 result_pool, scratch_pool));

  err = svn_ra_get_file(cb->pb->aux_session, path, base_revision,
                        fstream, NULL, NULL, scratch_pool);
  if (err && err->apr_err == SVN_ERR_FS_NOT_FOUND)
    {
      svn_error_clear(err);
      SVN_ERR(svn_stream_close(fstream));

      *filename = NULL;
      return SVN_NO_ERROR;
    }
  else if (err)
    return svn_error_trace(err);

  SVN_ERR(svn_stream_close(fstream));

  return SVN_NO_ERROR;
}

static svn_error_t *
fetch_props(apr_hash_t **props,
            void *baton,
            const char *path,
            svn_revnum_t base_revision,
            svn_node_kind_t node_kind,
            apr_pool_t *result_pool,
            apr_pool_t *scratch_pool)
{
  struct parse_baton *pb = baton;

  if (node_kind == svn_node_file)
    {
      SVN_ERR(svn_ra_get_file(pb->aux_session, path, base_revision,
                              NULL, NULL, props, result_pool));
    }
  else if (node_kind == svn_node_dir)
    {
      apr_array_header_t *tmp_props;

      SVN_ERR(svn_ra_get_dir2(pb->aux_session, NULL, NULL, props, path,
                              base_revision, 0 /* Dirent fields */,
                              result_pool));
      tmp_props = svn_prop_hash_to_array(*props, result_pool);
      SVN_ERR(svn_categorize_props(tmp_props, NULL, NULL, &tmp_props,
                                   result_pool));
      *props = svn_prop_array_to_hash(tmp_props, result_pool);
    }
  else
    {
      *props = apr_hash_make(result_pool);
    }

  return SVN_NO_ERROR;
}

static svn_error_t *
fetch_props_func(apr_hash_t **props,
                 void *baton,
                 const char *path,
                 svn_revnum_t base_revision,
                 apr_pool_t *result_pool,
                 apr_pool_t *scratch_pool)
{
  struct commit_baton_t *cb = baton;
  svn_node_kind_t node_kind;

  if (! SVN_IS_VALID_REVNUM(base_revision))
    base_revision = cb->rev - 1;

  SVN_ERR(svn_ra_check_path(cb->pb->aux_session, path, base_revision,
                            &node_kind, scratch_pool));
  SVN_ERR(fetch_props(props, cb->pb, path, base_revision, node_kind,
                      result_pool, scratch_pool));

  return SVN_NO_ERROR;
}

static svn_error_t *
fetch_kind_func(svn_node_kind_t *kind,
                void *baton,
                const char *path,
                svn_revnum_t base_revision,
                apr_pool_t *scratch_pool)
{
  struct commit_baton_t *cb = baton;

  if (! SVN_IS_VALID_REVNUM(base_revision))
    base_revision = cb->rev - 1;

  SVN_ERR(svn_ra_check_path(cb->pb->aux_session, path, base_revision,
                            kind, scratch_pool));

  return SVN_NO_ERROR;
}

static svn_delta_shim_callbacks_t *
get_shim_callbacks(struct commit_baton_t *cb,
                   apr_pool_t *pool)
{
  svn_delta_shim_callbacks_t *callbacks =
                        svn_delta_shim_callbacks_default(pool);

  callbacks->fetch_props_func = fetch_props_func;
  callbacks->fetch_kind_func = fetch_kind_func;
  callbacks->fetch_base_func = fetch_base_func;
  callbacks->fetch_baton = cb;

  return callbacks;
}

/*  */
static svn_error_t *
revstart(svn_revnum_t revision,
         void *baton,
         const svn_delta_editor_t **editor_p,
         void **edit_baton_p,
         apr_hash_t *rev_props,
         apr_pool_t *result_pool)
{
  struct parse_baton *pb = baton;
  struct commit_baton_t *cb = apr_palloc(result_pool, sizeof(*cb));

  cb->rev = revision;
  cb->pb = pb;
  SVN_ERR(svn_ra__register_editor_shim_callbacks(pb->session,
                                                 get_shim_callbacks(cb, result_pool)));
  SVN_ERR(svn_ra_get_commit_editor3(pb->session,
                                    editor_p, edit_baton_p,
                                    rev_props,
                                    commit_callback, cb,
                                    NULL, FALSE, result_pool));
  return SVN_NO_ERROR;
}

/* Return an implementation of the dumpstream parser API that will drive
 * commits over the RA layer to the location described by SESSION.
 *
 * Use AUX_SESSION (which is opened to the same URL as SESSION)
 * for any secondary, out-of-band RA communications required. This is
 * needed when loading a non-deltas dump, and for Ev2.
 *
 * Print feedback to the console for each revision, unless QUIET is true.
 *
 * Ignore (don't set) any revision property whose name is a key in
 * SKIP_REVPROPS. The values in the hash are unimportant.
 */
static svn_error_t *
get_dumpstream_loader(svn_repos_parse_fns3_t **parser_p,
                      void **parse_baton_p,
                      svn_ra_session_t *session,
                      svn_ra_session_t *aux_session,
                      svn_boolean_t quiet,
                      apr_hash_t *skip_revprops,
                      apr_pool_t *pool)
{
  svn_repos_parse_fns3_t *parser;
  struct parse_baton *parse_baton;
  const char *session_url, *root_url, *parent_dir;
  static const loader_fns_t callbacks = { revstart, fetch_props };

  SVN_ERR(svn_ra_get_repos_root2(session, &root_url, pool));
  SVN_ERR(svn_ra_get_session_url(session, &session_url, pool));
  SVN_ERR(svn_ra_get_path_relative_to_root(session, &parent_dir,
                                           session_url, pool));

  parser = apr_pcalloc(pool, sizeof(*parser));
  parser->magic_header_record = magic_header_record;
  parser->uuid_record = uuid_record;
  parser->new_revision_record = new_revision_record;
  parser->new_node_record = new_node_record;
  parser->set_revision_property = set_revision_property;
  parser->set_node_property = set_node_property;
  parser->delete_node_property = delete_node_property;
  parser->remove_node_props = remove_node_props;
  parser->set_fulltext = set_fulltext;
  parser->apply_textdelta = apply_textdelta;
  parser->close_node = close_node;
  parser->close_revision = close_revision;

  parse_baton = apr_pcalloc(pool, sizeof(*parse_baton));
  parse_baton->session = session;
  parse_baton->aux_session = aux_session;
  parse_baton->quiet = quiet;
  parse_baton->root_url = root_url;
  parse_baton->parent_dir = parent_dir;
  parse_baton->rev_map = apr_hash_make(pool);
  parse_baton->last_rev_mapped = SVN_INVALID_REVNUM;
  parse_baton->oldest_dumpstream_rev = SVN_INVALID_REVNUM;
  parse_baton->skip_revprops = skip_revprops;
  parse_baton->callbacks = &callbacks;
  parse_baton->cb_baton = parse_baton;

  *parser_p = parser;
  *parse_baton_p = parse_baton;
  return SVN_NO_ERROR;
}

/*----------------------------------------------------------------------*/

/* Dump-stream parser wrapper */

struct filter_parse_baton_t
{
  const svn_repos_parse_fns3_t *wrapped_parser;
  struct parse_baton *wrapped_pb;
};

struct filter_revision_baton_t
{
  struct filter_parse_baton_t *pb;
  void *wrapped_rb;
};

struct filter_node_baton_t
{
  struct filter_revision_baton_t *rb;
  void *wrapped_nb;
};

static svn_error_t *
filter_magic_header_record(int version,
                           void *parse_baton,
                           apr_pool_t *pool)
{
  struct filter_parse_baton_t *pb = parse_baton;

  SVN_ERR(pb->wrapped_parser->magic_header_record(version, pb->wrapped_pb,
                                                  pool));
  return SVN_NO_ERROR;
}

static svn_error_t *
filter_uuid_record(const char *uuid,
                   void *parse_baton,
                   apr_pool_t *pool)
{
  struct filter_parse_baton_t *pb = parse_baton;

  SVN_ERR(pb->wrapped_parser->uuid_record(uuid, pb->wrapped_pb, pool));
  return SVN_NO_ERROR;
}

static svn_error_t *
filter_new_revision_record(void **revision_baton,
                           apr_hash_t *headers,
                           void *parse_baton,
                           apr_pool_t *pool)
{
  struct filter_parse_baton_t *pb = parse_baton;
  struct filter_revision_baton_t *rb = apr_pcalloc(pool, sizeof (*rb));

  rb->pb = pb;
  SVN_ERR(pb->wrapped_parser->new_revision_record(&rb->wrapped_rb, headers,
                                                  pb->wrapped_pb, pool));
  *revision_baton = rb;
  return SVN_NO_ERROR;
}

static svn_error_t *
filter_new_node_record(void **node_baton,
                       apr_hash_t *headers,
                       void *revision_baton,
                       apr_pool_t *pool)
{
  struct filter_revision_baton_t *rb = revision_baton;
  struct filter_parse_baton_t *pb = rb->pb;
  struct filter_node_baton_t *nb = apr_pcalloc(pool, sizeof (*nb));

  nb->rb = rb;
  SVN_ERR(pb->wrapped_parser->new_node_record(&nb->wrapped_nb, headers,
                                              rb->wrapped_rb, pool));
  *node_baton = nb;
  return SVN_NO_ERROR;
}

static svn_error_t *
filter_set_revision_property(void *revision_baton,
                             const char *name,
                             const svn_string_t *value)
{
  struct filter_revision_baton_t *rb = revision_baton;
  struct filter_parse_baton_t *pb = rb->pb;

  SVN_ERR(pb->wrapped_parser->set_revision_property(rb->wrapped_rb,
                                                    name, value));
  return SVN_NO_ERROR;
}

static svn_error_t *
filter_set_node_property(void *node_baton,
                         const char *name,
                         const svn_string_t *value)
{
  struct filter_node_baton_t *nb = node_baton;
  struct filter_revision_baton_t *rb = nb->rb;
  struct filter_parse_baton_t *pb = rb->pb;

  SVN_ERR(pb->wrapped_parser->set_node_property(nb->wrapped_nb,
                                                name, value));
  return SVN_NO_ERROR;
}

static svn_error_t *
filter_delete_node_property(void *node_baton,
                            const char *name)
{
  struct filter_node_baton_t *nb = node_baton;
  struct filter_revision_baton_t *rb = nb->rb;
  struct filter_parse_baton_t *pb = rb->pb;

  SVN_ERR(pb->wrapped_parser->delete_node_property(nb->wrapped_nb, name));
  return SVN_NO_ERROR;
}

static svn_error_t *
filter_remove_node_props(void *node_baton)
{
  struct filter_node_baton_t *nb = node_baton;
  struct filter_revision_baton_t *rb = nb->rb;
  struct filter_parse_baton_t *pb = rb->pb;

  SVN_ERR(pb->wrapped_parser->remove_node_props(nb->wrapped_nb));
  return SVN_NO_ERROR;
}

static svn_error_t *
filter_set_fulltext(svn_stream_t **stream,
                    void *node_baton)
{
  struct filter_node_baton_t *nb = node_baton;
  struct filter_revision_baton_t *rb = nb->rb;
  struct filter_parse_baton_t *pb = rb->pb;

  SVN_ERR(pb->wrapped_parser->set_fulltext(stream, nb->wrapped_nb));
  return SVN_NO_ERROR;
}

static svn_error_t *
filter_apply_textdelta(svn_txdelta_window_handler_t *handler,
                       void **handler_baton,
                       void *node_baton)
{
  struct filter_node_baton_t *nb = node_baton;
  struct filter_revision_baton_t *rb = nb->rb;
  struct filter_parse_baton_t *pb = rb->pb;

  SVN_ERR(pb->wrapped_parser->apply_textdelta(handler, handler_baton,
                                              nb->wrapped_nb));
  return SVN_NO_ERROR;
}

static svn_error_t *
filter_close_node(void *node_baton)
{
  struct filter_node_baton_t *nb = node_baton;
  struct filter_revision_baton_t *rb = nb->rb;
  struct filter_parse_baton_t *pb = rb->pb;

  SVN_ERR(pb->wrapped_parser->close_node(nb->wrapped_nb));
  return SVN_NO_ERROR;
}

static svn_error_t *
filter_close_revision(void *revision_baton)
{
  struct filter_revision_baton_t *rb = revision_baton;
  struct filter_parse_baton_t *pb = rb->pb;

  SVN_ERR(pb->wrapped_parser->close_revision(rb->wrapped_rb));
  return SVN_NO_ERROR;
}

static svn_error_t *
get_dumpstream_filter(svn_repos_parse_fns3_t **parser_p,
                      void **parse_baton_p,
                      const svn_repos_parse_fns3_t *wrapped_parser,
                      void *wrapped_baton,
                      apr_pool_t *pool)
{
  svn_repos_parse_fns3_t *parser;
  struct filter_parse_baton_t *b;

  parser = apr_pcalloc(pool, sizeof(*parser));
  parser->magic_header_record = filter_magic_header_record;
  parser->uuid_record = filter_uuid_record;
  parser->new_revision_record = filter_new_revision_record;
  parser->new_node_record = filter_new_node_record;
  parser->set_revision_property = filter_set_revision_property;
  parser->set_node_property = filter_set_node_property;
  parser->delete_node_property = filter_delete_node_property;
  parser->remove_node_props = filter_remove_node_props;
  parser->set_fulltext = filter_set_fulltext;
  parser->apply_textdelta = filter_apply_textdelta;
  parser->close_node = filter_close_node;
  parser->close_revision = filter_close_revision;

  b = apr_pcalloc(pool, sizeof(*b));
  b->wrapped_parser = wrapped_parser;
  b->wrapped_pb = wrapped_baton;

  *parser_p = parser;
  *parse_baton_p = b;
  return SVN_NO_ERROR;
}

/*----------------------------------------------------------------------*/

/* Implements `svn_ra__lock_retry_func_t'. */
static svn_error_t *
lock_retry_func(void *baton,
                const svn_string_t *reposlocktoken,
                apr_pool_t *pool)
{
  return svn_cmdline_printf(pool,
                            _("Failed to get lock on destination "
                              "repos, currently held by '%s'\n"),
                            reposlocktoken->data);
}

/* Acquire a lock (of sorts) on the repository associated with the
 * given RA SESSION. This lock is just a revprop change attempt in a
 * time-delay loop. This function is duplicated by svnsync in
 * svnsync/svnsync.c
 *
 * ### TODO: Make this function more generic and
 * expose it through a header for use by other Subversion
 * applications to avoid duplication.
 */
static svn_error_t *
get_lock(const svn_string_t **lock_string_p,
         svn_ra_session_t *session,
         svn_cancel_func_t cancel_func,
         void *cancel_baton,
         apr_pool_t *pool)
{
  svn_boolean_t be_atomic;

  SVN_ERR(svn_ra_has_capability(session, &be_atomic,
                                SVN_RA_CAPABILITY_ATOMIC_REVPROPS,
                                pool));
  if (! be_atomic)
    {
      /* Pre-1.7 servers can't lock without a race condition.  (Issue #3546) */
      svn_error_t *err =
        svn_error_create(SVN_ERR_UNSUPPORTED_FEATURE, NULL,
                         _("Target server does not support atomic revision "
                           "property edits; consider upgrading it to 1.7."));
      svn_handle_warning2(stderr, err, "svnrdump: ");
      svn_error_clear(err);
    }

  return svn_ra__get_operational_lock(lock_string_p, NULL, session,
                                      SVNRDUMP_PROP_LOCK, FALSE,
                                      10 /* retries */, lock_retry_func, NULL,
                                      cancel_func, cancel_baton, pool);
}

svn_error_t *
svn_rdump__load_dumpstream(svn_stream_t *stream,
                           svn_ra_session_t *session,
                           svn_ra_session_t *aux_session,
                           svn_boolean_t quiet,
                           apr_hash_t *skip_revprops,
                           svn_cancel_func_t cancel_func,
                           void *cancel_baton,
                           apr_pool_t *pool)
{
  svn_repos_parse_fns3_t *parser;
  void *parse_baton;
  const svn_string_t *lock_string;
  svn_error_t *err;

  SVN_ERR(get_lock(&lock_string, session, cancel_func, cancel_baton, pool));

  SVN_ERR(get_dumpstream_loader(&parser, &parse_baton,
                                session, aux_session,
                                quiet, skip_revprops,
                                pool));

  /* Interpose a filtering layer: currently doing nothing */
  SVN_ERR(get_dumpstream_filter(&parser, &parse_baton,
                                parser, parse_baton,
                                pool));

  err = svn_repos_parse_dumpstream3(stream, parser, parse_baton, FALSE,
                                    cancel_func, cancel_baton, pool);

  /* If all goes well, or if we're cancelled cleanly, don't leave a
     stray lock behind. */
  if ((! err) || (err && (err->apr_err == SVN_ERR_CANCELLED)))
    err = svn_error_compose_create(
              svn_ra__release_operational_lock(session, SVNRDUMP_PROP_LOCK,
                                               lock_string, pool),
              err);
  return err;
}