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# Copyright (C) 2016-2022 The Software Heritage developers
# See the AUTHORS file at the top-level directory of this distribution
# License: GNU General Public License version 3, or any later version
# See top-level LICENSE file for more information
"""Remote Access client to svn server.
"""
from __future__ import annotations
import codecs
from collections import defaultdict
from dataclasses import dataclass, field
from itertools import chain
import logging
import os
import shutil
import tempfile
from typing import (
TYPE_CHECKING,
Any,
BinaryIO,
Callable,
Dict,
List,
Optional,
Set,
Tuple,
Union,
cast,
)
import click
from subvertpy import SubversionException, delta, properties
from subvertpy.ra import Auth, RemoteAccess, get_username_provider
from swh.model import from_disk, hashutil
from swh.model.from_disk import DiskBackedContent
from swh.model.model import Content, Directory, SkippedContent
if TYPE_CHECKING:
from swh.loader.svn.svn import SvnRepo
from swh.loader.svn.utils import parse_external_definition, svn_urljoin
_eol_style = {"native": b"\n", "CRLF": b"\r\n", "LF": b"\n", "CR": b"\r"}
logger = logging.getLogger(__name__)
def _normalize_line_endings(lines: bytes, eol_style: str = "native") -> bytes:
r"""Normalize line endings to unix (\\n), windows (\\r\\n) or mac (\\r).
Args:
lines: The lines to normalize
eol_style: The line ending format as defined for
svn:eol-style property. Acceptable values are 'native',
'CRLF', 'LF' and 'CR'
Returns:
Lines with endings normalized
"""
if eol_style in _eol_style:
lines = lines.replace(_eol_style["CRLF"], _eol_style["LF"]).replace(
_eol_style["CR"], _eol_style["LF"]
)
if _eol_style[eol_style] != _eol_style["LF"]:
lines = lines.replace(_eol_style["LF"], _eol_style[eol_style])
return lines
def apply_txdelta_handler(
sbuf: bytes, target_stream: BinaryIO
) -> Callable[[Any, bytes, BinaryIO], None]:
"""Return a function that can be called repeatedly with txdelta windows.
When done, closes the target_stream.
Adapted from subvertpy.delta.apply_txdelta_handler to close the
stream when done.
Args:
sbuf: Source buffer
target_stream: Target stream to write to.
Returns:
Function to be called to apply txdelta windows
"""
def apply_window(
window: Any, sbuf: bytes = sbuf, target_stream: BinaryIO = target_stream
):
if window is None:
target_stream.close()
return # Last call
patch = delta.apply_txdelta_window(sbuf, window)
target_stream.write(patch)
return apply_window
def read_svn_link(data: bytes) -> Tuple[bytes, bytes]:
"""Read the svn link's content.
Args:
data: svn link's raw content
Returns:
The tuple of (filetype, destination path)
"""
split_byte = b" "
first_line = data.split(b"\n")[0]
filetype, *src = first_line.split(split_byte)
target = split_byte.join(src)
return filetype, target
def is_file_an_svnlink_p(fullpath: bytes) -> Tuple[bool, bytes]:
"""Determine if a filepath is an svnlink or something else.
Args:
fullpath: Full path to the potential symlink to check
Returns:
Tuple containing a boolean value to determine if it's indeed a symlink
(as per svn) and the link target.
"""
if os.path.islink(fullpath):
return False, b""
with open(fullpath, "rb") as f:
filetype, src = read_svn_link(f.read())
return filetype == b"link", src
def _ra_codecs_error_handler(e: UnicodeError) -> Tuple[Union[str, bytes], int]:
"""Subvertpy may fail to decode to utf-8 the user svn properties. As
they are not used by the loader, return an empty string instead
of the decoded content.
Args:
e: exception raised during the svn properties decoding.
"""
return "", cast(UnicodeDecodeError, e).end
DEFAULT_FLAG = 0
EXEC_FLAG = 1
NOEXEC_FLAG = 2
SVN_PROPERTY_EOL = "svn:eol-style"
@dataclass
class FileState:
"""Persists some file states (eg. end of lines style) across revisions while
replaying them."""
eol_style: Optional[str] = None
"""EOL state check mess"""
svn_special_path_non_link_data: Optional[bytes] = None
"""keep track of non link file content with svn:special property set"""
# default value: 0, 1: set the flag, 2: remove the exec flag
executable: int = DEFAULT_FLAG
"""keep track if file is executable when setting svn:executable property"""
link: bool = False
"""keep track if file is a svn link when setting svn:special property"""
class FileEditor:
"""File Editor in charge of updating file on disk and memory objects.
"""
__slots__ = [
"directory",
"path",
"fullpath",
"executable",
"link",
"state",
"svnrepo",
"editor",
]
def __init__(
self,
directory: from_disk.Directory,
rootpath: bytes,
path: bytes,
state: FileState,
svnrepo: SvnRepo,
):
self.directory = directory
self.path = path
self.fullpath = os.path.join(rootpath, path)
self.state = state
self.svnrepo = svnrepo
self.editor = svnrepo.swhreplay.editor
self.editor.modified_paths.add(path)
def change_prop(self, key: str, value: str) -> None:
if key == properties.PROP_EXECUTABLE:
if value is None: # bit flip off
self.state.executable = NOEXEC_FLAG
else:
self.state.executable = EXEC_FLAG
elif key == properties.PROP_SPECIAL:
# Possibly a symbolic link. We cannot check further at
# that moment though, patch(s) not being applied yet
self.state.link = value is not None
elif key == SVN_PROPERTY_EOL:
# backup end of line style for file
self.state.eol_style = value
def __make_symlink(self, src: bytes) -> None:
"""Convert the svnlink to a symlink on disk.
This function expects self.fullpath to be a svn link.
Args:
src: Path to the link's source
Return:
tuple: The svnlink's data tuple:
- type (should be only 'link')
- <path-to-src>
"""
os.remove(self.fullpath)
os.symlink(src=src, dst=self.fullpath)
def __make_svnlink(self) -> bytes:
"""Convert the symlink to a svnlink on disk.
Return:
The symlink's svnlink data (``b'type <path-to-src>'``)
"""
# we replace the symlink by a svnlink
# to be able to patch the file on future commits
src = os.readlink(self.fullpath)
os.remove(self.fullpath)
sbuf = b"link " + src
with open(self.fullpath, "wb") as f:
f.write(sbuf)
return sbuf
def apply_textdelta(self, base_checksum) -> Callable[[Any, bytes, BinaryIO], None]:
# if the filepath matches an external, do not apply local patch
if self.path in self.editor.external_paths:
return lambda *args: None
if os.path.lexists(self.fullpath):
if os.path.islink(self.fullpath):
# svn does not deal with symlink so we transform into
# real svn symlink for potential patching in later
# commits
sbuf = self.__make_svnlink()
self.state.link = True
else:
with open(self.fullpath, "rb") as f:
sbuf = f.read()
else:
sbuf = b""
t = open(self.fullpath, "wb")
return apply_txdelta_handler(sbuf, target_stream=t)
def close(self) -> None:
"""When done with the file, this is called.
So the file exists and is updated, we can:
- adapt accordingly its execution flag if any
- compute the objects' checksums
- replace the svnlink with a real symlink (for disk
computation purposes)
"""
if self.state.link:
# can only check now that the link is a real one
# since patch has been applied
is_link, src = is_file_an_svnlink_p(self.fullpath)
if is_link:
self.__make_symlink(src)
elif not os.path.isdir(self.fullpath): # not a real link ...
# when a file with the svn:special property set is not a svn link,
# the svn export operation might extract a truncated version of it
# if it is a binary file, so ensure to produce the same file as the
# export operation.
with open(self.fullpath, "rb") as f:
content = f.read()
self.svnrepo.client.export(
os.path.join(self.svnrepo.remote_url.encode(), self.path),
to=self.fullpath,
rev=self.editor.revnum,
ignore_keywords=True,
overwrite=True,
)
with open(self.fullpath, "rb") as f:
exported_data = f.read()
if exported_data != content:
# keep track of original file content in order to restore
# it if the svn:special property gets unset in another revision
self.state.svn_special_path_non_link_data = content
elif os.path.islink(self.fullpath):
# path was a symbolic link in previous revision but got the property
# svn:special unset in current one, revert its content to svn link format
self.__make_svnlink()
elif self.state.svn_special_path_non_link_data is not None:
# path was a non link file with the svn:special property previously set
# and got truncated on export, restore its original content
with open(self.fullpath, "wb") as f:
f.write(self.state.svn_special_path_non_link_data)
self.state.svn_special_path_non_link_data = None
is_link = os.path.islink(self.fullpath)
if not is_link: # if a link, do nothing regarding flag
if self.state.executable == EXEC_FLAG:
os.chmod(self.fullpath, 0o755)
elif self.state.executable == NOEXEC_FLAG:
os.chmod(self.fullpath, 0o644)
# And now compute file's checksums
if self.state.eol_style and not is_link:
# ensure to normalize line endings as defined by svn:eol-style
# property to get the same file checksum as after an export
# or checkout operation with subversion
with open(self.fullpath, "rb") as f:
data = f.read()
data = _normalize_line_endings(data, self.state.eol_style)
mode = os.lstat(self.fullpath).st_mode
self.directory[self.path] = from_disk.Content.from_bytes(
mode=mode, data=data
)
else:
self.directory[self.path] = from_disk.Content.from_file(path=self.fullpath)
@dataclass
class DirState:
"""Persists some directory states (eg. externals) across revisions while
replaying them."""
externals: Dict[str, Tuple[str, Optional[int]]] = field(default_factory=dict)
class DirEditor:
"""Directory Editor in charge of updating directory hashes computation.
This implementation includes empty folder in the hash computation.
"""
__slots__ = [
"directory",
"rootpath",
"path",
"file_states",
"dir_states",
"svnrepo",
"editor",
"externals",
]
def __init__(
self,
directory: from_disk.Directory,
rootpath: bytes,
path: bytes,
file_states: Dict[bytes, FileState],
dir_states: Dict[bytes, DirState],
svnrepo: SvnRepo,
):
self.directory = directory
self.rootpath = rootpath
self.path = path
# build directory on init
os.makedirs(rootpath, exist_ok=True)
self.file_states = file_states
self.dir_states = dir_states
self.svnrepo = svnrepo
self.editor = svnrepo.swhreplay.editor
self.externals: Dict[str, Tuple[str, Optional[int], bool]] = {}
# repository root dir has empty path
if path:
self.editor.modified_paths.add(path)
def remove_child(self, path: bytes) -> None:
"""Remove a path from the current objects.
The path can be resolved as link, file or directory.
This function takes also care of removing the link between the
child and the parent.
Args:
path: to remove from the current objects.
"""
try:
entry_removed = self.directory[path]
except KeyError:
entry_removed = None
else:
del self.directory[path]
fpath = os.path.join(self.rootpath, path)
if isinstance(entry_removed, from_disk.Directory):
shutil.rmtree(fpath)
else:
os.remove(fpath)
# when deleting a directory ensure to remove any svn property for the
# file it contains as they can be added again later in another revision
# without the same property set
fullpath = os.path.join(self.rootpath, path)
for state_path in list(self.file_states):
if state_path.startswith(fullpath + b"/"):
del self.file_states[state_path]
self.editor.modified_paths.discard(path)
def open_directory(self, path: str, *args) -> DirEditor:
"""Updating existing directory.
"""
return DirEditor(
self.directory,
rootpath=self.rootpath,
path=os.fsencode(path),
file_states=self.file_states,
dir_states=self.dir_states,
svnrepo=self.svnrepo,
)
def add_directory(self, path: str, *args) -> DirEditor:
"""Adding a new directory.
"""
path_bytes = os.fsencode(path)
os.makedirs(os.path.join(self.rootpath, path_bytes), exist_ok=True)
if path_bytes and path_bytes not in self.directory:
self.dir_states[path_bytes] = DirState()
self.directory[path_bytes] = from_disk.Directory()
return DirEditor(
self.directory,
self.rootpath,
path_bytes,
self.file_states,
self.dir_states,
svnrepo=self.svnrepo,
)
def open_file(self, *args) -> FileEditor:
"""Updating existing file.
"""
path = os.fsencode(args[0])
self.directory[path] = from_disk.Content()
fullpath = os.path.join(self.rootpath, path)
return FileEditor(
self.directory,
rootpath=self.rootpath,
path=path,
state=self.file_states[fullpath],
svnrepo=self.svnrepo,
)
def add_file(self, path: str, *args) -> FileEditor:
"""Creating a new file.
"""
path_bytes = os.fsencode(path)
self.directory[path_bytes] = from_disk.Content()
fullpath = os.path.join(self.rootpath, path_bytes)
self.file_states[fullpath] = FileState()
return FileEditor(
self.directory,
self.rootpath,
path_bytes,
state=self.file_states[fullpath],
svnrepo=self.svnrepo,
)
def change_prop(self, key: str, value: str) -> None:
"""Change property callback on directory.
"""
if key == properties.PROP_EXTERNALS:
logger.debug(
"Setting '%s' property with value '%s' on path %s",
key,
value,
self.path,
)
self.externals = {}
if value is not None:
# externals are set on that directory path, parse and store them
# for later processing in the close method
for external in value.split("\n"):
external = external.rstrip("\r")
# skip empty line or comment
if not external or external.startswith("#"):
continue
(
path,
external_url,
revision,
relative_url,
) = parse_external_definition(
external, os.fsdecode(self.path), self.svnrepo.origin_url
)
self.externals[path] = (external_url, revision, relative_url)
if not self.externals:
# externals might have been unset on that directory path,
# remove associated paths from the reconstructed filesystem
externals = self.dir_states[self.path].externals
for path in externals.keys():
self.remove_external_path(os.fsencode(path))
self.dir_states[self.path].externals = {}
def delete_entry(self, path: str, revision: int) -> None:
"""Remove a path.
"""
path_bytes = os.fsencode(path)
if path_bytes not in self.editor.external_paths:
fullpath = os.path.join(self.rootpath, path_bytes)
self.file_states.pop(fullpath, None)
self.remove_child(path_bytes)
def close(self):
"""Function called when we finish processing a repository.
SVN external definitions are processed by it.
"""
prev_externals = self.dir_states[self.path].externals
if self.externals:
# externals definition list might have changed in the current processed
# revision, we need to determine if some were removed and delete the
# associated paths
old_externals = set(prev_externals) - set(self.externals)
for old_external in old_externals:
self.remove_external_path(os.fsencode(old_external))
# For each external, try to export it in reconstructed filesystem
for path, (external_url, revision, relative_url) in self.externals.items():
external = (external_url, revision)
dest_path = os.fsencode(path)
dest_fullpath = os.path.join(self.path, dest_path)
if (
path in prev_externals
and prev_externals[path] == external
and dest_fullpath in self.directory
):
# external already exported, nothing to do
continue
if external not in self.editor.externals_cache:
try:
# try to export external in a temporary path, destination path could
# be versioned and must be overridden only if the external URL is
# still valid
temp_dir = os.fsencode(
tempfile.mkdtemp(dir=self.editor.externals_cache_dir)
)
temp_path = os.path.join(temp_dir, dest_path)
os.makedirs(b"/".join(temp_path.split(b"/")[:-1]), exist_ok=True)
if external_url not in self.editor.dead_externals:
logger.debug(
"Exporting external %s to path %s", external_url, path
)
self.svnrepo.client.export(
external_url.rstrip("/"),
to=temp_path,
rev=revision,
ignore_keywords=True,
)
self.editor.externals_cache[external] = temp_path
self.editor.valid_externals[dest_fullpath] = (
external_url,
relative_url,
)
except SubversionException as se:
# external no longer available (404)
logger.debug(se)
self.editor.dead_externals.add(external_url)
else:
temp_path = self.editor.externals_cache[external]
# subversion export will always create the subdirectories of the external
# path regardless the validity of the remote URL
dest_path_split = dest_path.split(b"/")
current_path = self.path
self.add_directory(current_path)
for subpath in dest_path_split[:-1]:
current_path = os.path.join(current_path, subpath)
self.add_directory(current_path)
if os.path.exists(temp_path):
# external successfully exported
# remove previous path in from_disk model
self.remove_child(dest_fullpath)
# copy exported path to reconstructed filesystem
fullpath = os.path.join(self.rootpath, dest_fullpath)
self.editor.external_paths.add(dest_fullpath)
self.editor.modified_paths.add(dest_fullpath)
# update from_disk model and store external paths
self.editor.external_paths.add(dest_fullpath)
if os.path.isfile(temp_path):
shutil.copy(temp_path, fullpath)
self.directory[dest_fullpath] = from_disk.Content.from_file(
path=fullpath
)
else:
shutil.copytree(temp_path, fullpath, symlinks=True)
self.directory[dest_fullpath] = from_disk.Directory.from_disk(
path=fullpath
)
external_paths = set()
for root, dirs, files in os.walk(fullpath):
external_paths.update(
[
os.path.join(root.replace(self.rootpath + b"/", b""), p)
for p in chain(dirs, files)
]
)
self.editor.external_paths.update(external_paths)
self.editor.modified_paths.update(external_paths)
# ensure hash update for the directory with externals set
self.directory[self.path].update_hash(force=True)
# backup externals in directory state
if self.externals:
self.dir_states[self.path].externals = self.externals
self.svnrepo.has_relative_externals = any(
[relative_url for (_, relative_url) in self.editor.valid_externals.values()]
)
def remove_external_path(self, external_path: bytes) -> None:
"""Remove a previously exported SVN external path from
the reconstruted filesystem.
"""
fullpath = os.path.join(self.path, external_path)
self.remove_child(fullpath)
self.editor.external_paths.discard(fullpath)
self.editor.valid_externals.pop(fullpath, None)
for path in list(self.editor.external_paths):
if path.startswith(fullpath + b"/"):
self.editor.external_paths.remove(path)
subpath_split = external_path.split(b"/")[:-1]
for i in reversed(range(1, len(subpath_split) + 1)):
# delete external sub-directory only if it is empty
subpath = os.path.join(self.path, b"/".join(subpath_split[0:i]))
if not os.listdir(os.path.join(self.rootpath, subpath)):
self.remove_child(subpath)
else:
break
try:
# externals can overlap with versioned files so we must restore
# them after removing the path above
dest_path = os.path.join(self.rootpath, fullpath)
self.svnrepo.client.export(
svn_urljoin(self.svnrepo.remote_url, os.fsdecode(fullpath)),
to=dest_path,
rev=self.editor.revnum,
ignore_keywords=True,
)
if os.path.isfile(dest_path):
self.directory[fullpath] = from_disk.Content.from_file(path=dest_path)
else:
self.directory[fullpath] = from_disk.Directory.from_disk(path=dest_path)
except SubversionException:
pass
class Editor:
"""Editor in charge of replaying svn events and computing objects
along.
This implementation accounts for empty folder during hash
computations.
"""
def __init__(
self,
rootpath: bytes,
directory: from_disk.Directory,
svnrepo: SvnRepo,
temp_dir: str,
):
self.rootpath = rootpath
self.directory = directory
self.file_states: Dict[bytes, FileState] = defaultdict(FileState)
self.dir_states: Dict[bytes, DirState] = defaultdict(DirState)
self.external_paths: Set[bytes] = set()
self.valid_externals: Dict[bytes, Tuple[str, bool]] = {}
self.dead_externals: Set[str] = set()
self.externals_cache_dir = tempfile.mkdtemp(dir=temp_dir)
self.externals_cache: Dict[Tuple[str, Optional[int]], str] = {}
self.svnrepo = svnrepo
self.revnum = None
# to store the set of paths added or modified when replaying a revision
self.modified_paths: Set[bytes] = set()
def set_target_revision(self, revnum) -> None:
self.revnum = revnum
def abort(self) -> None:
pass
def close(self) -> None:
pass
def open_root(self, base_revnum: int) -> DirEditor:
# a new revision is being replayed so clear the modified_paths set
self.modified_paths.clear()
return DirEditor(
self.directory,
rootpath=self.rootpath,
path=b"",
file_states=self.file_states,
dir_states=self.dir_states,
svnrepo=self.svnrepo,
)
class Replay:
"""Replay class.
"""
def __init__(
self,
conn: RemoteAccess,
rootpath: bytes,
svnrepo: SvnRepo,
temp_dir: str,
directory: Optional[from_disk.Directory] = None,
):
self.conn = conn
self.rootpath = rootpath
if directory is None:
directory = from_disk.Directory()
self.directory = directory
self.editor = Editor(
rootpath=rootpath, directory=directory, svnrepo=svnrepo, temp_dir=temp_dir
)
def replay(self, rev: int) -> from_disk.Directory:
"""Replay svn actions between rev and rev+1.
This method updates in place the self.editor.directory, as well as the
filesystem.
Returns:
The updated root directory
"""
codecs.register_error("strict", _ra_codecs_error_handler)
self.conn.replay(rev, rev + 1, self.editor)
codecs.register_error("strict", codecs.strict_errors)
return self.editor.directory
def compute_objects(
self, rev: int
) -> Tuple[List[Content], List[SkippedContent], List[Directory]]:
"""Compute objects added or modified at revisions rev.
Expects the state to be at previous revision's objects.
Args:
rev: The revision to start the replay from.
Returns:
The updated objects between rev and rev+1. Beware that this
mutates the filesystem at rootpath accordingly.
"""
self.replay(rev)
contents: List[Content] = []
skipped_contents: List[SkippedContent] = []
directories: List[Directory] = []
directories.append(self.editor.directory.to_model())
for path in self.editor.modified_paths:
obj = self.directory[path].to_model()
obj_type = obj.object_type
if obj_type in (Content.object_type, DiskBackedContent.object_type):
contents.append(obj.with_data())
elif obj_type == SkippedContent.object_type:
skipped_contents.append(obj)
elif obj_type == Directory.object_type:
directories.append(obj)
return contents, skipped_contents, directories
@click.command()
@click.option("--local-url", default="/tmp", help="local svn working copy")
@click.option(
"--svn-url",
default="file:///home/storage/svn/repos/pkg-fox",
help="svn repository's url.",
)
@click.option(
"--revision-start",
default=1,
type=click.INT,
help="svn repository's starting revision.",
)
@click.option(
"--revision-end",
default=-1,
type=click.INT,
help="svn repository's ending revision.",
)
@click.option(
"--debug/--nodebug",
default=True,
help="Indicates if the server should run in debug mode.",
)
@click.option(
"--cleanup/--nocleanup",
default=True,
help="Indicates whether to cleanup disk when done or not.",
)
def main(local_url, svn_url, revision_start, revision_end, debug, cleanup):
"""Script to present how to use Replay class.
"""
conn = RemoteAccess(svn_url.encode("utf-8"), auth=Auth([get_username_provider()]))
os.makedirs(local_url, exist_ok=True)
rootpath = tempfile.mkdtemp(
prefix=local_url, suffix="-" + os.path.basename(svn_url)
)
rootpath = os.fsencode(rootpath)
# Do not go beyond the repository's latest revision
revision_end_max = conn.get_latest_revnum()
if revision_end == -1:
revision_end = revision_end_max
revision_end = min(revision_end, revision_end_max)
try:
replay = Replay(conn, rootpath)
for rev in range(revision_start, revision_end + 1):
contents, skipped_contents, directories = replay.compute_objects(rev)
print(
"r%s %s (%s new contents, %s new directories)"
% (
rev,
hashutil.hash_to_hex(replay.directory.hash),
len(contents) + len(skipped_contents),
len(directories),
)
)
if debug:
print("%s" % rootpath.decode("utf-8"))
finally:
if cleanup:
if os.path.exists(rootpath):
shutil.rmtree(rootpath)
if __name__ == "__main__":
main()

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