docs; fixed docstring

vcsserver/remote/svn_remote.py

@@ -1,941 +1,940 b''
 # RhodeCode VCSServer provides access to different vcs backends via network.
 # Copyright (C) 2014-2023 RhodeCode GmbH
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
 # the Free Software Foundation; either version 3 of the License, or
 # (at your option) any later version.
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
 # along with this program; if not, write to the Free Software Foundation,
 # Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA
 
 
 import os
 import subprocess
 from urllib.error import URLError
 import urllib.parse
 import logging
 import posixpath as vcspath
 import io
 import urllib.request
 import urllib.parse
 import urllib.error
 import traceback
 
 
 import svn.client  # noqa
 import svn.core  # noqa
 import svn.delta  # noqa
 import svn.diff  # noqa
 import svn.fs  # noqa
 import svn.repos  # noqa
 
 from vcsserver import svn_diff, exceptions, subprocessio, settings
 from vcsserver.base import (
     RepoFactory,
     raise_from_original,
     ArchiveNode,
     store_archive_in_cache,
     BytesEnvelope,
     BinaryEnvelope,
 )
 from vcsserver.exceptions import NoContentException
 from vcsserver.str_utils import safe_str, safe_bytes
 from vcsserver.type_utils import assert_bytes
 from vcsserver.vcs_base import RemoteBase
 from vcsserver.lib.svnremoterepo import svnremoterepo
 
 log = logging.getLogger(__name__)
 
 
 svn_compatible_versions_map = {
     'pre-1.4-compatible': '1.3',
     'pre-1.5-compatible': '1.4',
     'pre-1.6-compatible': '1.5',
     'pre-1.8-compatible': '1.7',
     'pre-1.9-compatible': '1.8',
 }
 
 current_compatible_version = '1.14'
 
 
 def reraise_safe_exceptions(func):
     """Decorator for converting svn exceptions to something neutral."""
     def wrapper(*args, **kwargs):
         try:
             return func(*args, **kwargs)
         except Exception as e:
             if not hasattr(e, '_vcs_kind'):
                 log.exception("Unhandled exception in svn remote call")
                 raise_from_original(exceptions.UnhandledException(e), e)
             raise
     return wrapper
 
 
 class SubversionFactory(RepoFactory):
     repo_type = 'svn'
 
     def _create_repo(self, wire, create, compatible_version):
         path = svn.core.svn_path_canonicalize(wire['path'])
         if create:
             fs_config = {'compatible-version': current_compatible_version}
             if compatible_version:
 
                 compatible_version_string = \
                     svn_compatible_versions_map.get(compatible_version) \
                     or compatible_version
                 fs_config['compatible-version'] = compatible_version_string
 
             log.debug('Create SVN repo with config `%s`', fs_config)
             repo = svn.repos.create(path, "", "", None, fs_config)
         else:
             repo = svn.repos.open(path)
 
         log.debug('repository created: got SVN object: %s', repo)
         return repo
 
     def repo(self, wire, create=False, compatible_version=None):
         """
         Get a repository instance for the given path.
         """
         return self._create_repo(wire, create, compatible_version)
 
 
 NODE_TYPE_MAPPING = {
     svn.core.svn_node_file: 'file',
     svn.core.svn_node_dir: 'dir',
 }
 
 
 class SvnRemote(RemoteBase):
 
     def __init__(self, factory, hg_factory=None):
         self._factory = factory
 
         self._bulk_methods = {
             # NOT supported in SVN ATM...
         }
         self._bulk_file_methods = {
             "size": self.get_file_size,
             "data": self.get_file_content,
             "flags": self.get_node_type,
             "is_binary": self.is_binary,
             "md5": self.md5_hash
         }
 
     @reraise_safe_exceptions
     def bulk_file_request(self, wire, commit_id, path, pre_load):
         cache_on, context_uid, repo_id = self._cache_on(wire)
         region = self._region(wire)
 
         # since we use unified API, we need to cast from str to in for SVN
         commit_id = int(commit_id)
 
         @region.conditional_cache_on_arguments(condition=cache_on)
         def _bulk_file_request(_repo_id, _commit_id, _path, _pre_load):
             result = {}
             for attr in pre_load:
                 try:
                     method = self._bulk_file_methods[attr]
                     wire.update({'cache': False})  # disable cache for bulk calls so we don't double cache
                     result[attr] = method(wire, _commit_id, _path)
                 except KeyError as e:
                     raise exceptions.VcsException(e)(f'Unknown bulk attribute: "{attr}"')
             return result
 
         return BinaryEnvelope(_bulk_file_request(repo_id, commit_id, path, sorted(pre_load)))
 
     @reraise_safe_exceptions
     def discover_svn_version(self):
         try:
             import svn.core
             svn_ver = svn.core.SVN_VERSION
         except ImportError:
             svn_ver = None
         return safe_str(svn_ver)
 
     @reraise_safe_exceptions
     def is_empty(self, wire):
         try:
             return self.lookup(wire, -1) == 0
         except Exception:
             log.exception("failed to read object_store")
             return False
 
     def check_url(self, url, config):
 
         # uuid function gets only valid UUID from proper repo, else
         # throws exception
         username, password, src_url = self.get_url_and_credentials(url)
         try:
             svnremoterepo(safe_bytes(username), safe_bytes(password), safe_bytes(src_url)).svn().uuid
         except Exception:
             tb = traceback.format_exc()
             log.debug("Invalid Subversion url: `%s`, tb: %s", url, tb)
             raise URLError(f'"{url}" is not a valid Subversion source url.')
         return True
 
     def is_path_valid_repository(self, wire, path):
-
         # NOTE(marcink):  short circuit the check for SVN repo
         # the repos.open might be expensive to check, but we have one cheap
-        # pre condition that we can use, to check for 'format' file
+        # pre-condition that we can use, to check for 'format' file
         if not os.path.isfile(os.path.join(path, 'format')):
             return False
 
         try:
             svn.repos.open(path)
         except svn.core.SubversionException:
             tb = traceback.format_exc()
             log.debug("Invalid Subversion path `%s`, tb: %s", path, tb)
             return False
         return True
 
     @reraise_safe_exceptions
     def verify(self, wire,):
         repo_path = wire['path']
         if not self.is_path_valid_repository(wire, repo_path):
             raise Exception(
                 f"Path {repo_path} is not a valid Subversion repository.")
 
         cmd = ['svnadmin', 'info', repo_path]
         stdout, stderr = subprocessio.run_command(cmd)
         return stdout
 
     @reraise_safe_exceptions
     def lookup(self, wire, revision):
         if revision not in [-1, None, 'HEAD']:
             raise NotImplementedError
         repo = self._factory.repo(wire)
         fs_ptr = svn.repos.fs(repo)
         head = svn.fs.youngest_rev(fs_ptr)
         return head
 
     @reraise_safe_exceptions
     def lookup_interval(self, wire, start_ts, end_ts):
         repo = self._factory.repo(wire)
         fsobj = svn.repos.fs(repo)
         start_rev = None
         end_rev = None
         if start_ts:
             start_ts_svn = apr_time_t(start_ts)
             start_rev = svn.repos.dated_revision(repo, start_ts_svn) + 1
         else:
             start_rev = 1
         if end_ts:
             end_ts_svn = apr_time_t(end_ts)
             end_rev = svn.repos.dated_revision(repo, end_ts_svn)
         else:
             end_rev = svn.fs.youngest_rev(fsobj)
         return start_rev, end_rev
 
     @reraise_safe_exceptions
     def revision_properties(self, wire, revision):
 
         cache_on, context_uid, repo_id = self._cache_on(wire)
         region = self._region(wire)
 
         @region.conditional_cache_on_arguments(condition=cache_on)
         def _revision_properties(_repo_id, _revision):
             repo = self._factory.repo(wire)
             fs_ptr = svn.repos.fs(repo)
             return svn.fs.revision_proplist(fs_ptr, revision)
         return _revision_properties(repo_id, revision)
 
     def revision_changes(self, wire, revision):
 
         repo = self._factory.repo(wire)
         fsobj = svn.repos.fs(repo)
         rev_root = svn.fs.revision_root(fsobj, revision)
 
         editor = svn.repos.ChangeCollector(fsobj, rev_root)
         editor_ptr, editor_baton = svn.delta.make_editor(editor)
         base_dir = ""
         send_deltas = False
         svn.repos.replay2(
             rev_root, base_dir, svn.core.SVN_INVALID_REVNUM, send_deltas,
             editor_ptr, editor_baton, None)
 
         added = []
         changed = []
         removed = []
 
         # TODO: CHANGE_ACTION_REPLACE: Figure out where it belongs
         for path, change in editor.changes.items():
             # TODO: Decide what to do with directory nodes. Subversion can add
             # empty directories.
 
             if change.item_kind == svn.core.svn_node_dir:
                 continue
             if change.action in [svn.repos.CHANGE_ACTION_ADD]:
                 added.append(path)
             elif change.action in [svn.repos.CHANGE_ACTION_MODIFY,
                                    svn.repos.CHANGE_ACTION_REPLACE]:
                 changed.append(path)
             elif change.action in [svn.repos.CHANGE_ACTION_DELETE]:
                 removed.append(path)
             else:
                 raise NotImplementedError(
                     "Action {} not supported on path {}".format(
                         change.action, path))
 
         changes = {
             'added': added,
             'changed': changed,
             'removed': removed,
         }
         return changes
 
     @reraise_safe_exceptions
     def node_history(self, wire, path, revision, limit):
         cache_on, context_uid, repo_id = self._cache_on(wire)
         region = self._region(wire)
 
         @region.conditional_cache_on_arguments(condition=cache_on)
         def _assert_correct_path(_context_uid, _repo_id, _path, _revision, _limit):
             cross_copies = False
             repo = self._factory.repo(wire)
             fsobj = svn.repos.fs(repo)
             rev_root = svn.fs.revision_root(fsobj, revision)
 
             history_revisions = []
             history = svn.fs.node_history(rev_root, path)
             history = svn.fs.history_prev(history, cross_copies)
             while history:
                 __, node_revision = svn.fs.history_location(history)
                 history_revisions.append(node_revision)
                 if limit and len(history_revisions) >= limit:
                     break
                 history = svn.fs.history_prev(history, cross_copies)
             return history_revisions
         return _assert_correct_path(context_uid, repo_id, path, revision, limit)
 
     @reraise_safe_exceptions
     def node_properties(self, wire, path, revision):
         cache_on, context_uid, repo_id = self._cache_on(wire)
         region = self._region(wire)
 
         @region.conditional_cache_on_arguments(condition=cache_on)
         def _node_properties(_repo_id, _path, _revision):
             repo = self._factory.repo(wire)
             fsobj = svn.repos.fs(repo)
             rev_root = svn.fs.revision_root(fsobj, revision)
             return svn.fs.node_proplist(rev_root, path)
         return _node_properties(repo_id, path, revision)
 
     def file_annotate(self, wire, path, revision):
         abs_path = 'file://' + urllib.request.pathname2url(
             vcspath.join(wire['path'], path))
         file_uri = svn.core.svn_path_canonicalize(abs_path)
 
         start_rev = svn_opt_revision_value_t(0)
         peg_rev = svn_opt_revision_value_t(revision)
         end_rev = peg_rev
 
         annotations = []
 
         def receiver(line_no, revision, author, date, line, pool):
             annotations.append((line_no, revision, line))
 
         # TODO: Cannot use blame5, missing typemap function in the swig code
         try:
             svn.client.blame2(
                 file_uri, peg_rev, start_rev, end_rev,
                 receiver, svn.client.create_context())
         except svn.core.SubversionException as exc:
             log.exception("Error during blame operation.")
             raise Exception(
                 f"Blame not supported or file does not exist at path {path}. "
                 f"Error {exc}.")
 
         return BinaryEnvelope(annotations)
 
     @reraise_safe_exceptions
     def get_node_type(self, wire, revision=None, path=''):
 
         cache_on, context_uid, repo_id = self._cache_on(wire)
         region = self._region(wire)
 
         @region.conditional_cache_on_arguments(condition=cache_on)
         def _get_node_type(_repo_id, _revision, _path):
             repo = self._factory.repo(wire)
             fs_ptr = svn.repos.fs(repo)
             if _revision is None:
                 _revision = svn.fs.youngest_rev(fs_ptr)
             root = svn.fs.revision_root(fs_ptr, _revision)
             node = svn.fs.check_path(root, path)
             return NODE_TYPE_MAPPING.get(node, None)
         return _get_node_type(repo_id, revision, path)
 
     @reraise_safe_exceptions
     def get_nodes(self, wire, revision=None, path=''):
 
         cache_on, context_uid, repo_id = self._cache_on(wire)
         region = self._region(wire)
 
         @region.conditional_cache_on_arguments(condition=cache_on)
         def _get_nodes(_repo_id, _path, _revision):
             repo = self._factory.repo(wire)
             fsobj = svn.repos.fs(repo)
             if _revision is None:
                 _revision = svn.fs.youngest_rev(fsobj)
             root = svn.fs.revision_root(fsobj, _revision)
             entries = svn.fs.dir_entries(root, path)
             result = []
             for entry_path, entry_info in entries.items():
                 result.append(
                     (entry_path, NODE_TYPE_MAPPING.get(entry_info.kind, None)))
             return result
         return _get_nodes(repo_id, path, revision)
 
     @reraise_safe_exceptions
     def get_file_content(self, wire, rev=None, path=''):
         repo = self._factory.repo(wire)
         fsobj = svn.repos.fs(repo)
 
         if rev is None:
             rev = svn.fs.youngest_rev(fsobj)
 
         root = svn.fs.revision_root(fsobj, rev)
         content = svn.core.Stream(svn.fs.file_contents(root, path))
         return BytesEnvelope(content.read())
 
     @reraise_safe_exceptions
     def get_file_size(self, wire, revision=None, path=''):
 
         cache_on, context_uid, repo_id = self._cache_on(wire)
         region = self._region(wire)
 
         @region.conditional_cache_on_arguments(condition=cache_on)
         def _get_file_size(_repo_id, _revision, _path):
             repo = self._factory.repo(wire)
             fsobj = svn.repos.fs(repo)
             if _revision is None:
                 _revision = svn.fs.youngest_revision(fsobj)
             root = svn.fs.revision_root(fsobj, _revision)
             size = svn.fs.file_length(root, path)
             return size
         return _get_file_size(repo_id, revision, path)
 
     def create_repository(self, wire, compatible_version=None):
         log.info('Creating Subversion repository in path "%s"', wire['path'])
         self._factory.repo(wire, create=True,
                            compatible_version=compatible_version)
 
     def get_url_and_credentials(self, src_url) -> tuple[str, str, str]:
         obj = urllib.parse.urlparse(src_url)
         username = obj.username or ''
         password = obj.password or ''
         return username, password, src_url
 
     def import_remote_repository(self, wire, src_url):
         repo_path = wire['path']
         if not self.is_path_valid_repository(wire, repo_path):
             raise Exception(
                 f"Path {repo_path} is not a valid Subversion repository.")
 
         username, password, src_url = self.get_url_and_credentials(src_url)
         rdump_cmd = ['svnrdump', 'dump', '--non-interactive',
                      '--trust-server-cert-failures=unknown-ca']
         if username and password:
             rdump_cmd += ['--username', username, '--password', password]
         rdump_cmd += [src_url]
 
         rdump = subprocess.Popen(
             rdump_cmd,
             stdout=subprocess.PIPE, stderr=subprocess.PIPE)
         load = subprocess.Popen(
             ['svnadmin', 'load', repo_path], stdin=rdump.stdout)
 
         # TODO: johbo: This can be a very long operation, might be better
         # to track some kind of status and provide an api to check if the
         # import is done.
         rdump.wait()
         load.wait()
 
         log.debug('Return process ended with code: %s', rdump.returncode)
         if rdump.returncode != 0:
             errors = rdump.stderr.read()
             log.error('svnrdump dump failed: statuscode %s: message: %s', rdump.returncode, errors)
 
             reason = 'UNKNOWN'
             if b'svnrdump: E230001:' in errors:
                 reason = 'INVALID_CERTIFICATE'
 
             if reason == 'UNKNOWN':
                 reason = f'UNKNOWN:{safe_str(errors)}'
 
             raise Exception(
                 'Failed to dump the remote repository from {}. Reason:{}'.format(
                     src_url, reason))
         if load.returncode != 0:
             raise Exception(
                 f'Failed to load the dump of remote repository from {src_url}.')
 
     def commit(self, wire, message, author, timestamp, updated, removed):
 
         message = safe_bytes(message)
         author = safe_bytes(author)
 
         repo = self._factory.repo(wire)
         fsobj = svn.repos.fs(repo)
 
         rev = svn.fs.youngest_rev(fsobj)
         txn = svn.repos.fs_begin_txn_for_commit(repo, rev, author, message)
         txn_root = svn.fs.txn_root(txn)
 
         for node in updated:
             TxnNodeProcessor(node, txn_root).update()
         for node in removed:
             TxnNodeProcessor(node, txn_root).remove()
 
         commit_id = svn.repos.fs_commit_txn(repo, txn)
 
         if timestamp:
             apr_time = apr_time_t(timestamp)
             ts_formatted = svn.core.svn_time_to_cstring(apr_time)
             svn.fs.change_rev_prop(fsobj, commit_id, 'svn:date', ts_formatted)
 
         log.debug('Committed revision "%s" to "%s".', commit_id, wire['path'])
         return commit_id
 
     @reraise_safe_exceptions
     def diff(self, wire, rev1, rev2, path1=None, path2=None,
              ignore_whitespace=False, context=3):
 
         wire.update(cache=False)
         repo = self._factory.repo(wire)
         diff_creator = SvnDiffer(
             repo, rev1, path1, rev2, path2, ignore_whitespace, context)
         try:
             return BytesEnvelope(diff_creator.generate_diff())
         except svn.core.SubversionException as e:
             log.exception(
                 "Error during diff operation operation. "
                 "Path might not exist %s, %s", path1, path2)
             return BytesEnvelope(b'')
 
     @reraise_safe_exceptions
     def is_large_file(self, wire, path):
         return False
 
     @reraise_safe_exceptions
     def is_binary(self, wire, rev, path):
         cache_on, context_uid, repo_id = self._cache_on(wire)
         region = self._region(wire)
 
         @region.conditional_cache_on_arguments(condition=cache_on)
         def _is_binary(_repo_id, _rev, _path):
             raw_bytes = self.get_file_content(wire, rev, path)
             if not raw_bytes:
                 return False
             return b'\0' in raw_bytes
 
         return _is_binary(repo_id, rev, path)
 
     @reraise_safe_exceptions
     def md5_hash(self, wire, rev, path):
         cache_on, context_uid, repo_id = self._cache_on(wire)
         region = self._region(wire)
 
         @region.conditional_cache_on_arguments(condition=cache_on)
         def _md5_hash(_repo_id, _rev, _path):
             return ''
 
         return _md5_hash(repo_id, rev, path)
 
     @reraise_safe_exceptions
     def run_svn_command(self, wire, cmd, **opts):
         path = wire.get('path', None)
 
         if path and os.path.isdir(path):
             opts['cwd'] = path
 
         safe_call = opts.pop('_safe', False)
 
         svnenv = os.environ.copy()
         svnenv.update(opts.pop('extra_env', {}))
 
         _opts = {'env': svnenv, 'shell': False}
 
         try:
             _opts.update(opts)
             proc = subprocessio.SubprocessIOChunker(cmd, **_opts)
 
             return b''.join(proc), b''.join(proc.stderr)
         except OSError as err:
             if safe_call:
                 return '', safe_str(err).strip()
             else:
                 cmd = ' '.join(map(safe_str, cmd))  # human friendly CMD
                 tb_err = ("Couldn't run svn command (%s).\n"
                           "Original error was:%s\n"
                           "Call options:%s\n"
                           % (cmd, err, _opts))
                 log.exception(tb_err)
                 raise exceptions.VcsException()(tb_err)
 
     @reraise_safe_exceptions
     def install_hooks(self, wire, force=False):
         from vcsserver.hook_utils import install_svn_hooks
         repo_path = wire['path']
         binary_dir = settings.BINARY_DIR
         executable = None
         if binary_dir:
             executable = os.path.join(binary_dir, 'python3')
         return install_svn_hooks(repo_path, force_create=force)
 
     @reraise_safe_exceptions
     def get_hooks_info(self, wire):
         from vcsserver.hook_utils import (
             get_svn_pre_hook_version, get_svn_post_hook_version)
         repo_path = wire['path']
         return {
             'pre_version': get_svn_pre_hook_version(repo_path),
             'post_version': get_svn_post_hook_version(repo_path),
         }
 
     @reraise_safe_exceptions
     def set_head_ref(self, wire, head_name):
         pass
 
     @reraise_safe_exceptions
     def archive_repo(self, wire, archive_name_key, kind, mtime, archive_at_path,
                      archive_dir_name, commit_id, cache_config):
 
         def walk_tree(root, root_dir, _commit_id):
             """
             Special recursive svn repo walker
             """
             root_dir = safe_bytes(root_dir)
 
             filemode_default = 0o100644
             filemode_executable = 0o100755
 
             file_iter = svn.fs.dir_entries(root, root_dir)
             for f_name in file_iter:
                 f_type = NODE_TYPE_MAPPING.get(file_iter[f_name].kind, None)
 
                 if f_type == 'dir':
                     # return only DIR, and then all entries in that dir
                     yield os.path.join(root_dir, f_name), {'mode': filemode_default}, f_type
                     new_root = os.path.join(root_dir, f_name)
                     yield from walk_tree(root, new_root, _commit_id)
                 else:
 
                     f_path = os.path.join(root_dir, f_name).rstrip(b'/')
                     prop_list = svn.fs.node_proplist(root, f_path)
 
                     f_mode = filemode_default
                     if prop_list.get('svn:executable'):
                         f_mode = filemode_executable
 
                     f_is_link = False
                     if prop_list.get('svn:special'):
                         f_is_link = True
 
                     data = {
                         'is_link': f_is_link,
                         'mode': f_mode,
                         'content_stream': svn.core.Stream(svn.fs.file_contents(root, f_path)).read
                     }
 
                     yield f_path, data, f_type
 
         def file_walker(_commit_id, path):
             repo = self._factory.repo(wire)
             root = svn.fs.revision_root(svn.repos.fs(repo), int(commit_id))
 
             def no_content():
                 raise NoContentException()
 
             for f_name, f_data, f_type in walk_tree(root, path, _commit_id):
                 file_path = f_name
 
                 if f_type == 'dir':
                     mode = f_data['mode']
                     yield ArchiveNode(file_path, mode, False, no_content)
                 else:
                     mode = f_data['mode']
                     is_link = f_data['is_link']
                     data_stream = f_data['content_stream']
                     yield ArchiveNode(file_path, mode, is_link, data_stream)
 
         return store_archive_in_cache(
             file_walker, archive_name_key, kind, mtime, archive_at_path, archive_dir_name, commit_id, cache_config=cache_config)
 
 
 class SvnDiffer:
     """
     Utility to create diffs based on difflib and the Subversion api
     """
 
     binary_content = False
 
     def __init__(
             self, repo, src_rev, src_path, tgt_rev, tgt_path,
             ignore_whitespace, context):
         self.repo = repo
         self.ignore_whitespace = ignore_whitespace
         self.context = context
 
         fsobj = svn.repos.fs(repo)
 
         self.tgt_rev = tgt_rev
         self.tgt_path = tgt_path or ''
         self.tgt_root = svn.fs.revision_root(fsobj, tgt_rev)
         self.tgt_kind = svn.fs.check_path(self.tgt_root, self.tgt_path)
 
         self.src_rev = src_rev
         self.src_path = src_path or self.tgt_path
         self.src_root = svn.fs.revision_root(fsobj, src_rev)
         self.src_kind = svn.fs.check_path(self.src_root, self.src_path)
 
         self._validate()
 
     def _validate(self):
         if (self.tgt_kind != svn.core.svn_node_none and
                 self.src_kind != svn.core.svn_node_none and
                 self.src_kind != self.tgt_kind):
             # TODO: johbo: proper error handling
             raise Exception(
                 "Source and target are not compatible for diff generation. "
                 "Source type: %s, target type: %s" %
                 (self.src_kind, self.tgt_kind))
 
     def generate_diff(self) -> bytes:
         buf = io.BytesIO()
         if self.tgt_kind == svn.core.svn_node_dir:
             self._generate_dir_diff(buf)
         else:
             self._generate_file_diff(buf)
         return buf.getvalue()
 
     def _generate_dir_diff(self, buf: io.BytesIO):
         editor = DiffChangeEditor()
         editor_ptr, editor_baton = svn.delta.make_editor(editor)
         svn.repos.dir_delta2(
             self.src_root,
             self.src_path,
             '',  # src_entry
             self.tgt_root,
             self.tgt_path,
             editor_ptr, editor_baton,
             authorization_callback_allow_all,
             False,  # text_deltas
             svn.core.svn_depth_infinity,  # depth
             False,  # entry_props
             False,  # ignore_ancestry
         )
 
         for path, __, change in sorted(editor.changes):
             self._generate_node_diff(
                 buf, change, path, self.tgt_path, path, self.src_path)
 
     def _generate_file_diff(self, buf: io.BytesIO):
         change = None
         if self.src_kind == svn.core.svn_node_none:
             change = "add"
         elif self.tgt_kind == svn.core.svn_node_none:
             change = "delete"
         tgt_base, tgt_path = vcspath.split(self.tgt_path)
         src_base, src_path = vcspath.split(self.src_path)
         self._generate_node_diff(
             buf, change, tgt_path, tgt_base, src_path, src_base)
 
     def _generate_node_diff(
             self, buf: io.BytesIO, change, tgt_path, tgt_base, src_path, src_base):
 
         tgt_path_bytes = safe_bytes(tgt_path)
         tgt_path = safe_str(tgt_path)
 
         src_path_bytes = safe_bytes(src_path)
         src_path = safe_str(src_path)
 
         if self.src_rev == self.tgt_rev and tgt_base == src_base:
             # makes consistent behaviour with git/hg to return empty diff if
             # we compare same revisions
             return
 
         tgt_full_path = vcspath.join(tgt_base, tgt_path)
         src_full_path = vcspath.join(src_base, src_path)
 
         self.binary_content = False
         mime_type = self._get_mime_type(tgt_full_path)
 
         if mime_type and not mime_type.startswith(b'text'):
             self.binary_content = True
             buf.write(b"=" * 67 + b'\n')
             buf.write(b"Cannot display: file marked as a binary type.\n")
             buf.write(b"svn:mime-type = %s\n" % mime_type)
         buf.write(b"Index: %b\n" % tgt_path_bytes)
         buf.write(b"=" * 67 + b'\n')
         buf.write(b"diff --git a/%b b/%b\n" % (tgt_path_bytes, tgt_path_bytes))
 
         if change == 'add':
             # TODO: johbo: SVN is missing a zero here compared to git
             buf.write(b"new file mode 10644\n")
 
             # TODO(marcink): intro to binary detection of svn patches
             # if self.binary_content:
             #     buf.write(b'GIT binary patch\n')
 
             buf.write(b"--- /dev/null\t(revision 0)\n")
             src_lines = []
         else:
             if change == 'delete':
                 buf.write(b"deleted file mode 10644\n")
 
             # TODO(marcink): intro to binary detection of svn patches
             # if self.binary_content:
             #     buf.write('GIT binary patch\n')
 
             buf.write(b"--- a/%b\t(revision %d)\n" % (src_path_bytes, self.src_rev))
             src_lines = self._svn_readlines(self.src_root, src_full_path)
 
         if change == 'delete':
             buf.write(b"+++ /dev/null\t(revision %d)\n" % self.tgt_rev)
             tgt_lines = []
         else:
             buf.write(b"+++ b/%b\t(revision %d)\n" % (tgt_path_bytes, self.tgt_rev))
             tgt_lines = self._svn_readlines(self.tgt_root, tgt_full_path)
 
         # we made our diff header, time to generate the diff content into our buffer
 
         if not self.binary_content:
             udiff = svn_diff.unified_diff(
                 src_lines, tgt_lines, context=self.context,
                 ignore_blank_lines=self.ignore_whitespace,
                 ignore_case=False,
                 ignore_space_changes=self.ignore_whitespace)
 
             buf.writelines(udiff)
 
     def _get_mime_type(self, path) -> bytes:
         try:
             mime_type = svn.fs.node_prop(
                 self.tgt_root, path, svn.core.SVN_PROP_MIME_TYPE)
         except svn.core.SubversionException:
             mime_type = svn.fs.node_prop(
                 self.src_root, path, svn.core.SVN_PROP_MIME_TYPE)
         return mime_type
 
     def _svn_readlines(self, fs_root, node_path):
         if self.binary_content:
             return []
         node_kind = svn.fs.check_path(fs_root, node_path)
         if node_kind not in (
                 svn.core.svn_node_file, svn.core.svn_node_symlink):
             return []
         content = svn.core.Stream(
             svn.fs.file_contents(fs_root, node_path)).read()
 
         return content.splitlines(True)
 
 
 class DiffChangeEditor(svn.delta.Editor):
     """
     Records changes between two given revisions
     """
 
     def __init__(self):
         self.changes = []
 
     def delete_entry(self, path, revision, parent_baton, pool=None):
         self.changes.append((path, None, 'delete'))
 
     def add_file(
             self, path, parent_baton, copyfrom_path, copyfrom_revision,
             file_pool=None):
         self.changes.append((path, 'file', 'add'))
 
     def open_file(self, path, parent_baton, base_revision, file_pool=None):
         self.changes.append((path, 'file', 'change'))
 
 
 def authorization_callback_allow_all(root, path, pool):
     return True
 
 
 class TxnNodeProcessor:
     """
     Utility to process the change of one node within a transaction root.
 
     It encapsulates the knowledge of how to add, update or remove
     a node for a given transaction root. The purpose is to support the method
     `SvnRemote.commit`.
     """
 
     def __init__(self, node, txn_root):
         assert_bytes(node['path'])
 
         self.node = node
         self.txn_root = txn_root
 
     def update(self):
         self._ensure_parent_dirs()
         self._add_file_if_node_does_not_exist()
         self._update_file_content()
         self._update_file_properties()
 
     def remove(self):
         svn.fs.delete(self.txn_root, self.node['path'])
         # TODO: Clean up directory if empty
 
     def _ensure_parent_dirs(self):
         curdir = vcspath.dirname(self.node['path'])
         dirs_to_create = []
         while not self._svn_path_exists(curdir):
             dirs_to_create.append(curdir)
             curdir = vcspath.dirname(curdir)
 
         for curdir in reversed(dirs_to_create):
             log.debug('Creating missing directory "%s"', curdir)
             svn.fs.make_dir(self.txn_root, curdir)
 
     def _svn_path_exists(self, path):
         path_status = svn.fs.check_path(self.txn_root, path)
         return path_status != svn.core.svn_node_none
 
     def _add_file_if_node_does_not_exist(self):
         kind = svn.fs.check_path(self.txn_root, self.node['path'])
         if kind == svn.core.svn_node_none:
             svn.fs.make_file(self.txn_root, self.node['path'])
 
     def _update_file_content(self):
         assert_bytes(self.node['content'])
 
         handler, baton = svn.fs.apply_textdelta(
             self.txn_root, self.node['path'], None, None)
         svn.delta.svn_txdelta_send_string(self.node['content'], handler, baton)
 
     def _update_file_properties(self):
         properties = self.node.get('properties', {})
         for key, value in properties.items():
             svn.fs.change_node_prop(
                 self.txn_root, self.node['path'], safe_bytes(key), safe_bytes(value))
 
 
 def apr_time_t(timestamp):
     """
     Convert a Python timestamp into APR timestamp type apr_time_t
     """
     return int(timestamp * 1E6)
 
 
 def svn_opt_revision_value_t(num):
     """
     Put `num` into a `svn_opt_revision_value_t` structure.
     """
     value = svn.core.svn_opt_revision_value_t()
     value.number = num
     revision = svn.core.svn_opt_revision_t()
     revision.kind = svn.core.svn_opt_revision_number
     revision.value = value
     return revision