/* noderevs.h --- FSX node revision container
 *
 * ====================================================================
 *    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_private_config.h"

#include "private/svn_dep_compat.h"
#include "private/svn_packed_data.h"
#include "private/svn_subr_private.h"
#include "private/svn_temp_serializer.h"

#include "noderevs.h"
#include "string_table.h"
#include "temp_serializer.h"

/* These flags will be used with the FLAGS field in binary_noderev_t.
 */

/* (flags & NODEREV_KIND_MASK) extracts the noderev type */
#define NODEREV_KIND_MASK    0x00007

/* the noderev has merge info */
#define NODEREV_HAS_MINFO    0x00008

/* the noderev has copy-from-path and revision */
#define NODEREV_HAS_COPYFROM 0x00010

/* the noderev has copy-root path and revision */
#define NODEREV_HAS_COPYROOT 0x00020

/* the noderev has copy-root path and revision */
#define NODEREV_HAS_CPATH    0x00040

/* Our internal representation of a svn_fs_x__noderev_t.
 *
 * We will store path strings in a string container and reference them
 * from here.  Similarly, IDs and representations are being stored in
 * separate containers and then also referenced here.  This eliminates
 * the need to store the same IDs and representations more than once.
 */
typedef struct binary_noderev_t
{
  /* node type and presence indicators */
  apr_uint32_t flags;

  /* Index+1 of the noderev-id for this node-rev. */
  int id;

  /* Index+1 of the node-id for this node-rev. */
  int node_id;

  /* Index+1 of the copy-id for this node-rev. */
  int copy_id;

  /* Index+1 of the predecessor node revision id, or 0 if there is no
     predecessor for this node revision */
  int predecessor_id;

  /* number of predecessors this node revision has (recursively), or
     -1 if not known (for backward compatibility). */
  int predecessor_count;

  /* If this node-rev is a copy, what revision was it copied from? */
  svn_revnum_t copyfrom_rev;

  /* Helper for history tracing, root revision of the parent tree from
     whence this node-rev was copied. */
  svn_revnum_t copyroot_rev;

  /* If this node-rev is a copy, this is the string index+1 of the path
     from which that copy way made. 0, otherwise. */
  apr_size_t copyfrom_path;

  /* String index+1 of the root of the parent tree from whence this node-
   * rev was copied. */
  apr_size_t copyroot_path;

  /* Index+1 of the representation key for this node's properties.
     May be 0 if there are no properties.  */
  int prop_rep;

  /* Index+1 of the representation for this node's data.
     May be 0 if there is no data. */
  int data_rep;

  /* String index+1 of the path at which this node first came into
     existence.  */
  apr_size_t created_path;

  /* Number of nodes with svn:mergeinfo properties that are
     descendants of this node (including it itself) */
  apr_int64_t mergeinfo_count;

} binary_noderev_t;

/* The actual container object.  Node revisions are concatenated into
 * NODEREVS, referenced representations are stored in DATA_REPS / PROP_REPS
 * and the ids in IDs.  PATHS is the string table for all paths.
 *
 * During construction, BUILDER will be used instead of PATHS. IDS_DICT,
 * DATA_REPS_DICT and PROP_REPS_DICT are also only used during construction
 * and are NULL otherwise.
 */
struct svn_fs_x__noderevs_t
{
  /* The paths - either in 'builder' mode or finalized mode.
   * The respective other pointer will be NULL. */
  string_table_builder_t *builder;
  string_table_t *paths;

  /* During construction, maps a full binary_id_t to an index into IDS */
  apr_hash_t *ids_dict;

  /* During construction, maps a full binary_representation_t to an index
   * into REPS. */
  apr_hash_t *reps_dict;

  /* array of binary_id_t */
  apr_array_header_t *ids;

  /* array of binary_representation_t */
  apr_array_header_t *reps;

  /* array of binary_noderev_t. */
  apr_array_header_t *noderevs;
};

svn_fs_x__noderevs_t *
svn_fs_x__noderevs_create(int initial_count,
                          apr_pool_t* result_pool)
{
  svn_fs_x__noderevs_t *noderevs
    = apr_palloc(result_pool, sizeof(*noderevs));

  noderevs->builder = svn_fs_x__string_table_builder_create(result_pool);
  noderevs->ids_dict = svn_hash__make(result_pool);
  noderevs->reps_dict = svn_hash__make(result_pool);
  noderevs->paths = NULL;

  noderevs->ids
    = apr_array_make(result_pool, 2 * initial_count, sizeof(svn_fs_x__id_t));
  noderevs->reps
    = apr_array_make(result_pool, 2 * initial_count,
                     sizeof(svn_fs_x__representation_t));
  noderevs->noderevs
    = apr_array_make(result_pool, initial_count, sizeof(binary_noderev_t));

  return noderevs;
}

/* Given the ID, return the index+1 into IDS that contains a binary_id
 * for it.  Returns 0 for NULL IDs.  We use DICT to detect duplicates.
 */
static int
store_id(apr_array_header_t *ids,
         apr_hash_t *dict,
         const svn_fs_x__id_t *id)
{
  int idx;
  void *idx_void;

  if (!svn_fs_x__id_used(id))
    return 0;

  idx_void = apr_hash_get(dict, &id, sizeof(id));
  idx = (int)(apr_uintptr_t)idx_void;
  if (idx == 0)
    {
      APR_ARRAY_PUSH(ids, svn_fs_x__id_t) = *id;
      idx = ids->nelts;
      apr_hash_set(dict, ids->elts + (idx-1) * ids->elt_size,
                   ids->elt_size, (void*)(apr_uintptr_t)idx);
    }

  return idx;
}

/* Given the REP, return the index+1 into REPS that contains a copy of it.
 * Returns 0 for NULL IDs.  We use DICT to detect duplicates.
 */
static int
store_representation(apr_array_header_t *reps,
                     apr_hash_t *dict,
                     const svn_fs_x__representation_t *rep)
{
  int idx;
  void *idx_void;

  if (rep == NULL)
    return 0;

  idx_void = apr_hash_get(dict, rep, sizeof(*rep));
  idx = (int)(apr_uintptr_t)idx_void;
  if (idx == 0)
    {
      APR_ARRAY_PUSH(reps, svn_fs_x__representation_t) = *rep;
      idx = reps->nelts;
      apr_hash_set(dict, reps->elts + (idx-1) * reps->elt_size,
                   reps->elt_size, (void*)(apr_uintptr_t)idx);
    }

  return idx;
}

apr_size_t
svn_fs_x__noderevs_add(svn_fs_x__noderevs_t *container,
                       svn_fs_x__noderev_t *noderev)
{
  binary_noderev_t binary_noderev = { 0 };

  binary_noderev.flags = (noderev->has_mergeinfo ? NODEREV_HAS_MINFO : 0)
                       | (noderev->copyfrom_path ? NODEREV_HAS_COPYFROM : 0)
                       | (noderev->copyroot_path  ? NODEREV_HAS_COPYROOT : 0)
                       | (noderev->created_path  ? NODEREV_HAS_CPATH : 0)
                       | (int)noderev->kind;

  binary_noderev.id
    = store_id(container->ids, container->ids_dict, &noderev->noderev_id);
  binary_noderev.node_id
    = store_id(container->ids, container->ids_dict, &noderev->node_id);
  binary_noderev.copy_id
    = store_id(container->ids, container->ids_dict, &noderev->copy_id);
  binary_noderev.predecessor_id
    = store_id(container->ids, container->ids_dict, &noderev->predecessor_id);

  if (noderev->copyfrom_path)
    {
      binary_noderev.copyfrom_path
        = svn_fs_x__string_table_builder_add(container->builder,
                                             noderev->copyfrom_path,
                                             0);
      binary_noderev.copyfrom_rev = noderev->copyfrom_rev;
    }

  if (noderev->copyroot_path)
    {
      binary_noderev.copyroot_path
        = svn_fs_x__string_table_builder_add(container->builder,
                                             noderev->copyroot_path,
                                             0);
      binary_noderev.copyroot_rev = noderev->copyroot_rev;
    }

  binary_noderev.predecessor_count = noderev->predecessor_count;
  binary_noderev.prop_rep = store_representation(container->reps,
                                                 container->reps_dict,
                                                 noderev->prop_rep);
  binary_noderev.data_rep = store_representation(container->reps,
                                                 container->reps_dict,
                                                 noderev->data_rep);

  if (noderev->created_path)
    binary_noderev.created_path
      = svn_fs_x__string_table_builder_add(container->builder,
                                           noderev->created_path,
                                           0);

  binary_noderev.mergeinfo_count = noderev->mergeinfo_count;

  APR_ARRAY_PUSH(container->noderevs, binary_noderev_t) = binary_noderev;

  return container->noderevs->nelts - 1;
}

apr_size_t
svn_fs_x__noderevs_estimate_size(const svn_fs_x__noderevs_t *container)
{
  /* CONTAINER must be in 'builder' mode */
  if (container->builder == NULL)
    return 0;

  /* string table code makes its own prediction,
   * noderevs should be < 16 bytes each,
   * id parts < 4 bytes each,
   * data representations < 40 bytes each,
   * property representations < 30 bytes each,
   * some static overhead should be assumed */
  return svn_fs_x__string_table_builder_estimate_size(container->builder)
       + container->noderevs->nelts * 16
       + container->ids->nelts * 4
       + container->reps->nelts * 40
       + 100;
}

/* Set *ID to the ID part stored at index IDX in IDS.
 */
static svn_error_t *
get_id(svn_fs_x__id_t *id,
       const apr_array_header_t *ids,
       int idx)
{
  /* handle NULL IDs  */
  if (idx == 0)
    {
      svn_fs_x__id_reset(id);
      return SVN_NO_ERROR;
    }

  /* check for corrupted data */
  if (idx < 0 || idx > ids->nelts)
    return svn_error_createf(SVN_ERR_FS_CONTAINER_INDEX, NULL,
                             _("ID part index %d exceeds container size %d"),
                             idx, ids->nelts);

  /* Return the requested ID. */
  *id = APR_ARRAY_IDX(ids, idx - 1, svn_fs_x__id_t);

  return SVN_NO_ERROR;
}

/* Create a svn_fs_x__representation_t in *REP, allocated in POOL based on the
 * representation stored at index IDX in REPS.
 */
static svn_error_t *
get_representation(svn_fs_x__representation_t **rep,
                   const apr_array_header_t *reps,
                   int idx,
                   apr_pool_t *pool)
{
  /* handle NULL representations  */
  if (idx == 0)
    {
      *rep = NULL;
      return SVN_NO_ERROR;
    }

  /* check for corrupted data */
  if (idx < 0 || idx > reps->nelts)
    return svn_error_createf(SVN_ERR_FS_CONTAINER_INDEX, NULL,
                             _("Node revision ID index %d"
                               " exceeds container size %d"),
                             idx, reps->nelts);

  /* no translation required. Just duplicate the info */
  *rep = apr_pmemdup(pool,
                     &APR_ARRAY_IDX(reps, idx - 1, svn_fs_x__representation_t),
                     sizeof(**rep));

  return SVN_NO_ERROR;
}

svn_error_t *
svn_fs_x__noderevs_get(svn_fs_x__noderev_t **noderev_p,
                       const svn_fs_x__noderevs_t *container,
                       apr_size_t idx,
                       apr_pool_t *result_pool)
{
  svn_fs_x__noderev_t *noderev;
  binary_noderev_t *binary_noderev;

  /* CONTAINER must be in 'finalized' mode */
  SVN_ERR_ASSERT(container->builder == NULL);
  SVN_ERR_ASSERT(container->paths);

  /* validate index */
  if (idx >= (apr_size_t)container->noderevs->nelts)
    return svn_error_createf(SVN_ERR_FS_CONTAINER_INDEX, NULL,
                             apr_psprintf(result_pool,
                                          _("Node revision index %%%s"
                                            " exceeds container size %%d"),
                                          APR_SIZE_T_FMT),
                             idx, container->noderevs->nelts);

  /* allocate result struct and fill it field by field */
  noderev = apr_pcalloc(result_pool, sizeof(*noderev));
  binary_noderev = &APR_ARRAY_IDX(container->noderevs, idx, binary_noderev_t);

  noderev->kind = (svn_node_kind_t)(binary_noderev->flags & NODEREV_KIND_MASK);
  SVN_ERR(get_id(&noderev->noderev_id, container->ids, binary_noderev->id));
  SVN_ERR(get_id(&noderev->node_id, container->ids,
                 binary_noderev->node_id));
  SVN_ERR(get_id(&noderev->copy_id, container->ids,
                 binary_noderev->copy_id));
  SVN_ERR(get_id(&noderev->predecessor_id, container->ids,
                 binary_noderev->predecessor_id));

  if (binary_noderev->flags & NODEREV_HAS_COPYFROM)
    {
      noderev->copyfrom_path
        = svn_fs_x__string_table_get(container->paths,
                                     binary_noderev->copyfrom_path,
                                     NULL,
                                     result_pool);
      noderev->copyfrom_rev = binary_noderev->copyfrom_rev;
    }
  else
    {
      noderev->copyfrom_path = NULL;
      noderev->copyfrom_rev = SVN_INVALID_REVNUM;
    }

  if (binary_noderev->flags & NODEREV_HAS_COPYROOT)
    {
      noderev->copyroot_path
        = svn_fs_x__string_table_get(container->paths,
                                     binary_noderev->copyroot_path,
                                     NULL,
                                     result_pool);
      noderev->copyroot_rev = binary_noderev->copyroot_rev;
    }
  else
    {
      noderev->copyroot_path = NULL;
      noderev->copyroot_rev = 0;
    }

  noderev->predecessor_count = binary_noderev->predecessor_count;

  SVN_ERR(get_representation(&noderev->prop_rep, container->reps,
                             binary_noderev->prop_rep, result_pool));
  SVN_ERR(get_representation(&noderev->data_rep, container->reps,
                             binary_noderev->data_rep, result_pool));

  if (binary_noderev->flags & NODEREV_HAS_CPATH)
    noderev->created_path
      = svn_fs_x__string_table_get(container->paths,
                                   binary_noderev->created_path,
                                   NULL,
                                   result_pool);

  noderev->mergeinfo_count = binary_noderev->mergeinfo_count;

  noderev->has_mergeinfo = (binary_noderev->flags & NODEREV_HAS_MINFO) ? 1 : 0;
  *noderev_p = noderev;

  return SVN_NO_ERROR;
}

/* Create and return a stream for representations in PARENT.
 * Initialize the sub-streams for all fields, except checksums.
 */
static svn_packed__int_stream_t *
create_rep_stream(svn_packed__int_stream_t *parent)
{
  svn_packed__int_stream_t *stream
    = svn_packed__create_int_substream(parent, FALSE, FALSE);

  /* sub-streams for members - except for checksums */
  /* has_sha1 */
  svn_packed__create_int_substream(stream, FALSE, FALSE);

  /* rev, item_index, size, expanded_size */
  svn_packed__create_int_substream(stream, TRUE, FALSE);
  svn_packed__create_int_substream(stream, FALSE, FALSE);
  svn_packed__create_int_substream(stream, FALSE, FALSE);
  svn_packed__create_int_substream(stream, FALSE, FALSE);

  return stream;
}

/* Serialize all representations in REP.  Store checksums in DIGEST_STREAM,
 * put all other fields into REP_STREAM.
 */
static void
write_reps(svn_packed__int_stream_t *rep_stream,
           svn_packed__byte_stream_t *digest_stream,
           apr_array_header_t *reps)
{
  int i;
  for (i = 0; i < reps->nelts; ++i)
    {
      svn_fs_x__representation_t *rep
        = &APR_ARRAY_IDX(reps, i, svn_fs_x__representation_t);

      svn_packed__add_uint(rep_stream, rep->has_sha1);

      svn_packed__add_uint(rep_stream, rep->id.change_set);
      svn_packed__add_uint(rep_stream, rep->id.number);
      svn_packed__add_uint(rep_stream, rep->size);
      svn_packed__add_uint(rep_stream, rep->expanded_size);

      svn_packed__add_bytes(digest_stream,
                            (const char *)rep->md5_digest,
                            sizeof(rep->md5_digest));
      if (rep->has_sha1)
        svn_packed__add_bytes(digest_stream,
                              (const char *)rep->sha1_digest,
                              sizeof(rep->sha1_digest));
    }
}

svn_error_t *
svn_fs_x__write_noderevs_container(svn_stream_t *stream,
                                   const svn_fs_x__noderevs_t *container,
                                   apr_pool_t *scratch_pool)
{
  int i;

  string_table_t *paths = container->paths
                        ? container->paths
                        : svn_fs_x__string_table_create(container->builder,
                                                        scratch_pool);

  svn_packed__data_root_t *root = svn_packed__data_create_root(scratch_pool);

  /* one common top-level stream for all arrays. One sub-stream */
  svn_packed__int_stream_t *structs_stream
    = svn_packed__create_int_stream(root, FALSE, FALSE);
  svn_packed__int_stream_t *ids_stream
    = svn_packed__create_int_substream(structs_stream, FALSE, FALSE);
  svn_packed__int_stream_t *reps_stream
    = create_rep_stream(structs_stream);
  svn_packed__int_stream_t *noderevs_stream
    = svn_packed__create_int_substream(structs_stream, FALSE, FALSE);
  svn_packed__byte_stream_t *digests_stream
    = svn_packed__create_bytes_stream(root);

  /* structure the IDS_STREAM such we can extract much of the redundancy
   * from the svn_fs_x__ip_part_t structs */
  for (i = 0; i < 2; ++i)
    svn_packed__create_int_substream(ids_stream, TRUE, FALSE);

  /* Same storing binary_noderev_t in the NODEREVS_STREAM */
  svn_packed__create_int_substream(noderevs_stream, FALSE, FALSE);
  for (i = 0; i < 13; ++i)
    svn_packed__create_int_substream(noderevs_stream, TRUE, FALSE);

  /* serialize ids array */
  for (i = 0; i < container->ids->nelts; ++i)
    {
      svn_fs_x__id_t *id = &APR_ARRAY_IDX(container->ids, i, svn_fs_x__id_t);

      svn_packed__add_int(ids_stream, id->change_set);
      svn_packed__add_uint(ids_stream, id->number);
    }

  /* serialize rep arrays */
  write_reps(reps_stream, digests_stream, container->reps);

  /* serialize noderevs array */
  for (i = 0; i < container->noderevs->nelts; ++i)
    {
      const binary_noderev_t *noderev
        = &APR_ARRAY_IDX(container->noderevs, i, binary_noderev_t);

      svn_packed__add_uint(noderevs_stream, noderev->flags);

      svn_packed__add_uint(noderevs_stream, noderev->id);
      svn_packed__add_uint(noderevs_stream, noderev->node_id);
      svn_packed__add_uint(noderevs_stream, noderev->copy_id);
      svn_packed__add_uint(noderevs_stream, noderev->predecessor_id);
      svn_packed__add_uint(noderevs_stream, noderev->predecessor_count);

      svn_packed__add_uint(noderevs_stream, noderev->copyfrom_path);
      svn_packed__add_int(noderevs_stream, noderev->copyfrom_rev);
      svn_packed__add_uint(noderevs_stream, noderev->copyroot_path);
      svn_packed__add_int(noderevs_stream, noderev->copyroot_rev);

      svn_packed__add_uint(noderevs_stream, noderev->prop_rep);
      svn_packed__add_uint(noderevs_stream, noderev->data_rep);

      svn_packed__add_uint(noderevs_stream, noderev->created_path);
      svn_packed__add_uint(noderevs_stream, noderev->mergeinfo_count);
    }

  /* write to disk */
  SVN_ERR(svn_fs_x__write_string_table(stream, paths, scratch_pool));
  SVN_ERR(svn_packed__data_write(stream, root, scratch_pool));

  return SVN_NO_ERROR;
}

/* Allocate a svn_fs_x__representation_t array in RESULT_POOL and return it
 * in REPS_P.  Deserialize the data in REP_STREAM and DIGEST_STREAM and store
 * the resulting representations into the *REPS_P.
 */
static svn_error_t *
read_reps(apr_array_header_t **reps_p,
          svn_packed__int_stream_t *rep_stream,
          svn_packed__byte_stream_t *digest_stream,
          apr_pool_t *result_pool)
{
  apr_size_t i;
  apr_size_t len;
  const char *bytes;

  apr_size_t count
    = svn_packed__int_count(svn_packed__first_int_substream(rep_stream));
  apr_array_header_t *reps
    = apr_array_make(result_pool, (int)count,
                     sizeof(svn_fs_x__representation_t));

  for (i = 0; i < count; ++i)
    {
      svn_fs_x__representation_t rep;

      rep.has_sha1 = (svn_boolean_t)svn_packed__get_uint(rep_stream);

      rep.id.change_set = (svn_revnum_t)svn_packed__get_uint(rep_stream);
      rep.id.number = svn_packed__get_uint(rep_stream);
      rep.size = svn_packed__get_uint(rep_stream);
      rep.expanded_size = svn_packed__get_uint(rep_stream);

      /* when extracting the checksums, beware of buffer under/overflows
         caused by disk data corruption. */
      bytes = svn_packed__get_bytes(digest_stream, &len);
      if (len != sizeof(rep.md5_digest))
        return svn_error_createf(SVN_ERR_FS_CONTAINER_INDEX, NULL,
                                 apr_psprintf(result_pool,
                                              _("Unexpected MD5"
                                                " digest size %%%s"),
                                              APR_SIZE_T_FMT),
                                 len);

      memcpy(rep.md5_digest, bytes, sizeof(rep.md5_digest));
      if (rep.has_sha1)
        {
          bytes = svn_packed__get_bytes(digest_stream, &len);
          if (len != sizeof(rep.sha1_digest))
            return svn_error_createf(SVN_ERR_FS_CONTAINER_INDEX, NULL,
                                     apr_psprintf(result_pool,
                                                  _("Unexpected SHA1"
                                                    " digest size %%%s"),
                                                  APR_SIZE_T_FMT),
                                     len);

          memcpy(rep.sha1_digest, bytes, sizeof(rep.sha1_digest));
        }

      APR_ARRAY_PUSH(reps, svn_fs_x__representation_t) = rep;
    }

  *reps_p = reps;

  return SVN_NO_ERROR;
}

svn_error_t *
svn_fs_x__read_noderevs_container(svn_fs_x__noderevs_t **container,
                                  svn_stream_t *stream,
                                  apr_pool_t *result_pool,
                                  apr_pool_t *scratch_pool)
{
  apr_size_t i;
  apr_size_t count;

  svn_fs_x__noderevs_t *noderevs
    = apr_pcalloc(result_pool, sizeof(*noderevs));

  svn_packed__data_root_t *root;
  svn_packed__int_stream_t *structs_stream;
  svn_packed__int_stream_t *ids_stream;
  svn_packed__int_stream_t *reps_stream;
  svn_packed__int_stream_t *noderevs_stream;
  svn_packed__byte_stream_t *digests_stream;

  /* read everything from disk */
  SVN_ERR(svn_fs_x__read_string_table(&noderevs->paths, stream,
                                      result_pool, scratch_pool));
  SVN_ERR(svn_packed__data_read(&root, stream, result_pool, scratch_pool));

  /* get streams */
  structs_stream = svn_packed__first_int_stream(root);
  ids_stream = svn_packed__first_int_substream(structs_stream);
  reps_stream = svn_packed__next_int_stream(ids_stream);
  noderevs_stream = svn_packed__next_int_stream(reps_stream);
  digests_stream = svn_packed__first_byte_stream(root);

  /* read ids array */
  count
    = svn_packed__int_count(svn_packed__first_int_substream(ids_stream));
  noderevs->ids
    = apr_array_make(result_pool, (int)count, sizeof(svn_fs_x__id_t));
  for (i = 0; i < count; ++i)
    {
      svn_fs_x__id_t id;

      id.change_set = (svn_revnum_t)svn_packed__get_int(ids_stream);
      id.number = svn_packed__get_uint(ids_stream);

      APR_ARRAY_PUSH(noderevs->ids, svn_fs_x__id_t) = id;
    }

  /* read rep arrays */
  SVN_ERR(read_reps(&noderevs->reps, reps_stream, digests_stream,
                    result_pool));

  /* read noderevs array */
  count
    = svn_packed__int_count(svn_packed__first_int_substream(noderevs_stream));
  noderevs->noderevs
    = apr_array_make(result_pool, (int)count, sizeof(binary_noderev_t));
  for (i = 0; i < count; ++i)
    {
      binary_noderev_t noderev;

      noderev.flags = (apr_uint32_t)svn_packed__get_uint(noderevs_stream);

      noderev.id = (int)svn_packed__get_uint(noderevs_stream);
      noderev.node_id = (int)svn_packed__get_uint(noderevs_stream);
      noderev.copy_id = (int)svn_packed__get_uint(noderevs_stream);
      noderev.predecessor_id = (int)svn_packed__get_uint(noderevs_stream);
      noderev.predecessor_count = (int)svn_packed__get_uint(noderevs_stream);

      noderev.copyfrom_path = (apr_size_t)svn_packed__get_uint(noderevs_stream);
      noderev.copyfrom_rev = (svn_revnum_t)svn_packed__get_int(noderevs_stream);
      noderev.copyroot_path = (apr_size_t)svn_packed__get_uint(noderevs_stream);
      noderev.copyroot_rev = (svn_revnum_t)svn_packed__get_int(noderevs_stream);

      noderev.prop_rep = (int)svn_packed__get_uint(noderevs_stream);
      noderev.data_rep = (int)svn_packed__get_uint(noderevs_stream);

      noderev.created_path = (apr_size_t)svn_packed__get_uint(noderevs_stream);
      noderev.mergeinfo_count = svn_packed__get_uint(noderevs_stream);

      APR_ARRAY_PUSH(noderevs->noderevs, binary_noderev_t) = noderev;
    }

  *container = noderevs;

  return SVN_NO_ERROR;
}

svn_error_t *
svn_fs_x__serialize_noderevs_container(void **data,
                                       apr_size_t *data_len,
                                       void *in,
                                       apr_pool_t *pool)
{
  svn_fs_x__noderevs_t *noderevs = in;
  svn_stringbuf_t *serialized;
  apr_size_t size
    = noderevs->ids->elt_size * noderevs->ids->nelts
    + noderevs->reps->elt_size * noderevs->reps->nelts
    + noderevs->noderevs->elt_size * noderevs->noderevs->nelts
    + 10 * noderevs->noderevs->elt_size
    + 100;

  /* serialize array header and all its elements */
  svn_temp_serializer__context_t *context
    = svn_temp_serializer__init(noderevs, sizeof(*noderevs), size, pool);

  /* serialize sub-structures */
  svn_fs_x__serialize_string_table(context, &noderevs->paths);
  svn_fs_x__serialize_apr_array(context, &noderevs->ids);
  svn_fs_x__serialize_apr_array(context, &noderevs->reps);
  svn_fs_x__serialize_apr_array(context, &noderevs->noderevs);

  /* return the serialized result */
  serialized = svn_temp_serializer__get(context);

  *data = serialized->data;
  *data_len = serialized->len;

  return SVN_NO_ERROR;
}

svn_error_t *
svn_fs_x__deserialize_noderevs_container(void **out,
                                         void *data,
                                         apr_size_t data_len,
                                         apr_pool_t *result_pool)
{
  svn_fs_x__noderevs_t *noderevs = (svn_fs_x__noderevs_t *)data;

  /* de-serialize sub-structures */
  svn_fs_x__deserialize_string_table(noderevs, &noderevs->paths);
  svn_fs_x__deserialize_apr_array(noderevs, &noderevs->ids, result_pool);
  svn_fs_x__deserialize_apr_array(noderevs, &noderevs->reps, result_pool);
  svn_fs_x__deserialize_apr_array(noderevs, &noderevs->noderevs, result_pool);

  /* done */
  *out = noderevs;

  return SVN_NO_ERROR;
}

/* Deserialize the cache serialized APR struct at *IN in BUFFER and write
 * the result to OUT.  Note that this will only resolve the pointers and
 * not the array elements themselves. */
static void
resolve_apr_array_header(apr_array_header_t *out,
                         const void *buffer,
                         apr_array_header_t * const *in)
{
  const apr_array_header_t *array
    = svn_temp_deserializer__ptr(buffer, (const void *const *)in);
  const char *elements
    = svn_temp_deserializer__ptr(array, (const void *const *)&array->elts);

  *out = *array;
  out->elts = (char *)elements;
  out->pool = NULL;
}

svn_error_t *
svn_fs_x__noderevs_get_func(void **out,
                            const void *data,
                            apr_size_t data_len,
                            void *baton,
                            apr_pool_t *pool)
{
  svn_fs_x__noderev_t *noderev;
  binary_noderev_t *binary_noderev;

  apr_array_header_t ids;
  apr_array_header_t reps;
  apr_array_header_t noderevs;

  apr_uint32_t idx = *(apr_uint32_t *)baton;
  const svn_fs_x__noderevs_t *container = data;

  /* Resolve all container pointers */
  const string_table_t *paths
    = svn_temp_deserializer__ptr(container,
                         (const void *const *)&container->paths);

  resolve_apr_array_header(&ids, container, &container->ids);
  resolve_apr_array_header(&reps, container, &container->reps);
  resolve_apr_array_header(&noderevs, container, &container->noderevs);

  /* allocate result struct and fill it field by field */
  noderev = apr_pcalloc(pool, sizeof(*noderev));
  binary_noderev = &APR_ARRAY_IDX(&noderevs, idx, binary_noderev_t);

  noderev->kind = (svn_node_kind_t)(binary_noderev->flags & NODEREV_KIND_MASK);
  SVN_ERR(get_id(&noderev->noderev_id, &ids, binary_noderev->id));
  SVN_ERR(get_id(&noderev->node_id, &ids, binary_noderev->node_id));
  SVN_ERR(get_id(&noderev->copy_id, &ids, binary_noderev->copy_id));
  SVN_ERR(get_id(&noderev->predecessor_id, &ids,
                 binary_noderev->predecessor_id));

  if (binary_noderev->flags & NODEREV_HAS_COPYFROM)
    {
      noderev->copyfrom_path
        = svn_fs_x__string_table_get_func(paths,
                                          binary_noderev->copyfrom_path,
                                          NULL,
                                          pool);
      noderev->copyfrom_rev = binary_noderev->copyfrom_rev;
    }
  else
    {
      noderev->copyfrom_path = NULL;
      noderev->copyfrom_rev = SVN_INVALID_REVNUM;
    }

  if (binary_noderev->flags & NODEREV_HAS_COPYROOT)
    {
      noderev->copyroot_path
        = svn_fs_x__string_table_get_func(paths,
                                          binary_noderev->copyroot_path,
                                          NULL,
                                          pool);
      noderev->copyroot_rev = binary_noderev->copyroot_rev;
    }
  else
    {
      noderev->copyroot_path = NULL;
      noderev->copyroot_rev = 0;
    }

  noderev->predecessor_count = binary_noderev->predecessor_count;

  SVN_ERR(get_representation(&noderev->prop_rep, &reps,
                             binary_noderev->prop_rep, pool));
  SVN_ERR(get_representation(&noderev->data_rep, &reps,
                             binary_noderev->data_rep, pool));

  if (binary_noderev->flags & NODEREV_HAS_CPATH)
    noderev->created_path
      = svn_fs_x__string_table_get_func(paths,
                                        binary_noderev->created_path,
                                        NULL,
                                        pool);

  noderev->mergeinfo_count = binary_noderev->mergeinfo_count;

  noderev->has_mergeinfo = (binary_noderev->flags & NODEREV_HAS_MINFO) ? 1 : 0;
  *out = noderev;

  return SVN_NO_ERROR;
}

svn_error_t *
svn_fs_x__mergeinfo_count_get_func(void **out,
                                   const void *data,
                                   apr_size_t data_len,
                                   void *baton,
                                   apr_pool_t *pool)
{
  binary_noderev_t *binary_noderev;
  apr_array_header_t noderevs;

  apr_uint32_t idx = *(apr_uint32_t *)baton;
  const svn_fs_x__noderevs_t *container = data;

  /* Resolve all container pointers */
  resolve_apr_array_header(&noderevs, container, &container->noderevs);
  binary_noderev = &APR_ARRAY_IDX(&noderevs, idx, binary_noderev_t);

  *(apr_int64_t *)out = binary_noderev->mergeinfo_count;

  return SVN_NO_ERROR;
}