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#!/usr/bin/env python3
#
# Copyright (C) 2018 Bloomberg Finance LP
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2 of the License, or (at your option) any later version.
#
# This library 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
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library. If not, see <http://www.gnu.org/licenses/>.
#
# Authors:
# Jim MacArthur <jim.macarthur@codethink.co.uk>
"""
FileBasedDirectory
=========
Implementation of the Directory class which backs onto a normal POSIX filing system.
See also: :ref:`sandboxing`.
"""
import os
import time
from .._exceptions import BstError, ErrorDomain
from .directory import Directory
from ..utils import link_files, copy_files, list_relative_paths, _get_link_mtime, _magic_timestamp
from ..utils import _set_deterministic_user, _set_deterministic_mtime
class VirtualDirectoryError(BstError):
"""Raised by Directory functions when system calls fail.
This will be handled internally by the BuildStream core,
if you need to handle this error, then it should be reraised,
or either of the :class:`.ElementError` or :class:`.SourceError`
exceptions should be raised from this error.
"""
def __init__(self, message, reason=None):
super().__init__(message, domain=ErrorDomain.VIRTUAL_FS, reason=reason)
# FileBasedDirectory intentionally doesn't call its superclass constuctor,
# which is mean to be unimplemented.
# pylint: disable=super-init-not-called
class _FileObject():
"""A description of a file in a virtual directory. The contents of
this class are never used, but there needs to be something present
for files so is_empty() works correctly.
"""
def __init__(self, virtual_directory: Directory, filename: str):
self.directory = virtual_directory
self.filename = filename
class FileBasedDirectory(Directory):
def __init__(self, external_directory=None):
self.external_directory = external_directory
self.index = {}
self._directory_read = False
def _populate_index(self):
if self._directory_read:
return
for entry in os.listdir(self.external_directory):
if os.path.isdir(os.path.join(self.external_directory, entry)):
self.index[entry] = FileBasedDirectory(os.path.join(self.external_directory, entry))
else:
self.index[entry] = _FileObject(self, entry)
self._directory_read = True
def descend(self, subdirectory_spec, create=False):
""" See superclass Directory for arguments """
# It's very common to send a directory name instead of a list and this causes
# bizarre errors, so check for it here
if not isinstance(subdirectory_spec, list):
subdirectory_spec = [subdirectory_spec]
# Because of the way split works, it's common to get a list which begins with
# an empty string. Detect these and remove them.
while subdirectory_spec and subdirectory_spec[0] == "":
subdirectory_spec.pop(0)
if not subdirectory_spec:
return self
self._populate_index()
if subdirectory_spec[0] in self.index:
entry = self.index[subdirectory_spec[0]]
if isinstance(entry, FileBasedDirectory):
new_path = os.path.join(self.external_directory, subdirectory_spec[0])
return FileBasedDirectory(new_path).descend(subdirectory_spec[1:], create)
else:
error = "Cannot descend into {}, which is a '{}' in the directory {}"
raise VirtualDirectoryError(error.format(subdirectory_spec[0],
type(entry).__name__,
self.external_directory))
else:
if create:
new_path = os.path.join(self.external_directory, subdirectory_spec[0])
os.makedirs(new_path, exist_ok=True)
return FileBasedDirectory(new_path).descend(subdirectory_spec[1:], create)
else:
error = "No entry called '{}' found in the directory rooted at {}"
raise VirtualDirectoryError(error.format(subdirectory_spec[0], self.external_directory))
def import_files(self, external_pathspec, *, files=None,
report_written=True, update_utimes=False,
can_link=False):
""" See superclass Directory for arguments """
if isinstance(external_pathspec, Directory):
source_directory = external_pathspec.external_directory
else:
source_directory = external_pathspec
if can_link and not update_utimes:
import_result = link_files(source_directory, self.external_directory, files=files,
ignore_missing=False, report_written=report_written)
else:
import_result = copy_files(source_directory, self.external_directory, files=files,
ignore_missing=False, report_written=report_written)
if update_utimes:
cur_time = time.time()
for f in import_result.files_written:
os.utime(os.path.join(self.external_directory, f), times=(cur_time, cur_time))
return import_result
def set_deterministic_mtime(self):
_set_deterministic_mtime(self.external_directory)
def set_deterministic_user(self):
_set_deterministic_user(self.external_directory)
def export_files(self, to_directory, *, can_link=False, can_destroy=False):
if can_destroy:
# Try a simple rename of the sandbox root; if that
# doesnt cut it, then do the regular link files code path
try:
os.rename(self.external_directory, to_directory)
return
except OSError:
# Proceed using normal link/copy
pass
os.makedirs(to_directory, exist_ok=True)
if can_link:
link_files(self.external_directory, to_directory)
else:
copy_files(self.external_directory, to_directory)
# Add a directory entry deterministically to a tar file
#
# This function takes extra steps to ensure the output is deterministic.
# First, it sorts the results of os.listdir() to ensure the ordering of
# the files in the archive is the same. Second, it sets a fixed
# timestamp for each entry. See also https://bugs.python.org/issue24465.
def export_to_tar(self, tf, dir_arcname, mtime=0):
# We need directories here, including non-empty ones,
# so list_relative_paths is not used.
for filename in sorted(os.listdir(self.external_directory)):
source_name = os.path.join(self.external_directory, filename)
arcname = os.path.join(dir_arcname, filename)
tarinfo = tf.gettarinfo(source_name, arcname)
tarinfo.mtime = mtime
if tarinfo.isreg():
with open(source_name, "rb") as f:
tf.addfile(tarinfo, f)
elif tarinfo.isdir():
tf.addfile(tarinfo)
self.descend(filename.split(os.path.sep)).export_to_tar(tf, arcname, mtime)
else:
tf.addfile(tarinfo)
def is_empty(self):
self._populate_index()
return len(self.index) == 0
def mark_unmodified(self):
""" Marks all files in this directory (recursively) as unmodified.
"""
_set_deterministic_mtime(self.external_directory)
def list_modified_paths(self):
"""Provide a list of relative paths which have been modified since the
last call to mark_unmodified.
Return value: List(str) - list of modified paths
"""
return [f for f in list_relative_paths(self.external_directory)
if _get_link_mtime(os.path.join(self.external_directory, f)) != _magic_timestamp]
def list_relative_paths(self):
"""Provide a list of all relative paths.
Return value: List(str) - list of all paths
"""
return list_relative_paths(self.external_directory)
def __str__(self):
# This returns the whole path (since we don't know where the directory started)
# which exposes the sandbox directory; we will have to assume for the time being
# that people will not abuse __str__.
return self.external_directory
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