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Diffstat (limited to 'buildstream/storage/_filebaseddirectory.py')
| -rw-r--r-- | buildstream/storage/_filebaseddirectory.py | 253 |
1 files changed, 253 insertions, 0 deletions
diff --git a/buildstream/storage/_filebaseddirectory.py b/buildstream/storage/_filebaseddirectory.py new file mode 100644 index 000000000..60379eaed --- /dev/null +++ b/buildstream/storage/_filebaseddirectory.py @@ -0,0 +1,253 @@ +#!/usr/bin/env python3 +# +# Copyright (C) 2018 Codethink Limited +# +# 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`. +""" + +from typing import List +from collections import OrderedDict + +import calendar +import os +import time +from .._exceptions import BstError, ErrorDomain +from .directory import Directory +from ..utils import link_files, copy_files, FileListResult, list_relative_paths +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) + + +# Like os.path.getmtime(), but doesnt explode on symlinks +# Copy/pasted from compose.py +def getmtime(path): + stat = os.lstat(path) + return stat.st_mtime + +# 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 = OrderedDict() + self._directory_read = False + + def _populate_index(self) -> None: + 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: List[str], create: bool = False) -> Directory: + """ Descend one or more levels of directory hierarchy and return a new + Directory object for that directory. + + Arguments: + * subdirectory_spec (list of strings): A list of strings which are all directory + names. + * create (boolean): If this is true, the directories will be created if + they don't already exist. + """ + + # 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] + if not subdirectory_spec: + return self + + # Because of the way split works, it's common to get a list which begins with + # an empty string. Detect these and remove them, then start again. + if subdirectory_spec[0] == "": + return self.descend(subdirectory_spec[1:], create) + + 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)) + return None + + def import_files(self, external_pathspec: any, files: List[str] = None, + report_written: bool = True, update_utimes: bool = False, + can_link: bool = False) -> FileListResult: + """Imports some or all files from external_path into this directory. + + Keyword arguments: external_pathspec: Either a string + containing a pathname, or a Directory object, to use as the + source. + + files (list of strings): A list of all the files relative to + the external_pathspec to copy. If 'None' is supplied, all + files are copied. + + report_written (bool): Return the full list of files + written. Defaults to true. If false, only a list of + overwritten files is returned. + + update_utimes (bool): Update the access and modification time + of each file copied to the current time. + + can_link (bool): Whether it's OK to create a hard link to the + original content, meaning the stored copy will change when the + original files change. Setting this doesn't guarantee hard + links will be made. can_link will never be used if + update_utimes is set. + """ + + 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) -> None: + """ Sets a static modification time for all regular files in this directory. + The magic number for timestamps: 2011-11-11 11:11:11 + """ + _set_deterministic_mtime(self.external_directory) + + def set_deterministic_user(self) -> None: + """ Sets all files in this directory to the current user's euid/egid. + """ + _set_deterministic_user(self.external_directory) + + def export_files(self, to_directory: str, can_link: bool = False, can_destroy: bool = False) -> None: + """Copies everything from this into to_directory. + + Arguments: + + to_directory (string): a path outside this directory object + where the contents will be copied to. + + can_link (bool): Whether we can create hard links in to_directory + instead of copying. + + """ + + 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 + + if can_link: + link_files(self.external_directory, to_directory) + else: + copy_files(self.external_directory, to_directory) + + def is_empty(self) -> bool: + """ Return true if this directory has no files, subdirectories or links in it. + """ + self._populate_index() + return len(self.index) == 0 + + def mark_unmodified(self) -> None: + """ Marks all files in this directory (recursively) as unmodified. + """ + _set_deterministic_mtime(self.external_directory) + + def list_modified_paths(self) -> List[str]: + """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 + """ + magic_timestamp = calendar.timegm([2011, 11, 11, 11, 11, 11]) + + return [f for f in list_relative_paths(self.external_directory) + if getmtime(os.path.join(self.external_directory, f)) != magic_timestamp] + + def list_relative_paths(self) -> List[str]: + """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) -> str: + # 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 |