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Posted to commits@buildstream.apache.org by gi...@apache.org on 2020/12/29 13:05:07 UTC
[buildstream] 03/12: Add the virtual directory class 'Directory'
and one implementation.
This is an automated email from the ASF dual-hosted git repository.
github-bot pushed a commit to branch jmac/virtual_directories_pre_rebase
in repository https://gitbox.apache.org/repos/asf/buildstream.git
commit 227bc2042b4c4edfd853a995ebca8967307e3e1a
Author: Jim MacArthur <ji...@codethink.co.uk>
AuthorDate: Tue May 8 16:08:12 2018 +0100
Add the virtual directory class 'Directory' and one implementation.
buildstream/storage/Directory.py: New file.
buildstream/storage/_filebaseddirectory.py: New file.
buildstream/_exceptions.py: New VIRTUAL_FS exception source.
---
buildstream/_exceptions.py | 1 +
buildstream/element.py | 1 -
buildstream/storage/_filebaseddirectory.py | 226 +++++++++++++++++++++++++++++
buildstream/storage/directory.py | 155 ++++++++++++++++++++
4 files changed, 382 insertions(+), 1 deletion(-)
diff --git a/buildstream/_exceptions.py b/buildstream/_exceptions.py
index 8baf167..b46bba9 100644
--- a/buildstream/_exceptions.py
+++ b/buildstream/_exceptions.py
@@ -88,6 +88,7 @@ class ErrorDomain(Enum):
ELEMENT = 11
APP = 12
STREAM = 13
+ VIRTUAL_FS = 14
# BstError is an internal base exception class for BuildSream
diff --git a/buildstream/element.py b/buildstream/element.py
index 1f985ae..7964db6 100644
--- a/buildstream/element.py
+++ b/buildstream/element.py
@@ -97,7 +97,6 @@ from . import _site
from ._platform import Platform
from .sandbox._config import SandboxConfig
-
# _KeyStrength():
#
# Strength of cache key
diff --git a/buildstream/storage/_filebaseddirectory.py b/buildstream/storage/_filebaseddirectory.py
new file mode 100644
index 0000000..57de1ef
--- /dev/null
+++ b/buildstream/storage/_filebaseddirectory.py
@@ -0,0 +1,226 @@
+#!/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 <ji...@codethink.co.uk>
+
+"""
+FileBasedDirectory
+=========
+
+Implementation of the Directory class which backs onto a normal POSIX filing system.
+
+See also: :ref:`sandboxing`.
+"""
+
+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, 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):
+ 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]
+ 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))
+
+ 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
+ """
+ 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):
+ """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
diff --git a/buildstream/storage/directory.py b/buildstream/storage/directory.py
new file mode 100644
index 0000000..f70863f
--- /dev/null
+++ b/buildstream/storage/directory.py
@@ -0,0 +1,155 @@
+#!/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 <ji...@codethink.co.uk>
+
+"""
+Directory
+=========
+
+This is a virtual Directory class to isolate the rest of BuildStream
+from the backing store implementation. Sandboxes are allowed to read
+from and write to the underlying storage, but all others must use this
+Directory class to access files and directories in the sandbox.
+
+See also: :ref:`sandboxing`.
+
+"""
+
+
+class Directory():
+ def __init__(self, external_directory=None):
+ raise NotImplementedError()
+
+ def descend(self, subdirectory_spec, create=False):
+ """Descend one or more levels of directory hierarchy and return a new
+ Directory object for that directory.
+
+ Args:
+ subdirectory_spec (list of str): 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.
+
+ Yields:
+ A Directory object representing the found directory.
+
+ Raises:
+ VirtualDirectoryError: if any of the components in subdirectory_spec
+ cannot be found, or are files, or symlinks to files.
+
+ """
+ raise NotImplementedError()
+
+ # Import and export of files and links
+ def import_files(self, external_pathspec, *, files=None,
+ report_written=True, update_utimes=False,
+ can_link=False):
+ """Imports some or all files from external_path into this directory.
+
+ Args:
+ external_pathspec: Either a string containing a pathname, or a
+ Directory object, to use as the source.
+ files (list of str): 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.
+
+ Yields:
+ (FileListResult) - A report of files imported and overwritten.
+
+ """
+
+ raise NotImplementedError()
+
+ def export_files(self, to_directory, *, can_link=False, can_destroy=False):
+ """Copies everything from this into to_directory.
+
+ Args:
+ 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. Setting this does not guarantee hard links will be used.
+ can_destroy (bool): Can we destroy the data already in this
+ directory when exporting? If set, this may allow data to be
+ moved rather than copied which will be quicker.
+ """
+
+ raise NotImplementedError()
+
+ def export_to_tar(self, tarfile, destination_dir, mtime=0):
+ """ Exports this directory into the given tar file.
+
+ Args:
+ tarfile (TarFile): A Python TarFile object to export into.
+ destination_dir (str): The prefix for all filenames inside the archive.
+ mtime (int): mtimes of all files in the archive are set to this.
+ """
+ raise NotImplementedError()
+
+ # Convenience functions
+ def is_empty(self):
+ """ Return true if this directory has no files, subdirectories or links in it.
+ """
+ raise NotImplementedError()
+
+ def set_deterministic_mtime(self):
+ """ Sets a static modification time for all regular files in this directory.
+ The magic number for timestamps is 2011-11-11 11:11:11.
+ """
+ raise NotImplementedError()
+
+ def set_deterministic_user(self):
+ """ Sets all files in this directory to the current user's euid/egid.
+ """
+ raise NotImplementedError()
+
+ def mark_unmodified(self):
+ """ Marks all files in this directory (recursively) as unmodified.
+ """
+ raise NotImplementedError()
+
+ def list_modified_paths(self):
+ """Provide a list of relative paths which have been modified since the
+ last call to mark_unmodified. Includes directories only if
+ they are empty.
+
+ Yields:
+ (List(str)) - list of all modified files with relative paths.
+
+ """
+ raise NotImplementedError()
+
+ def list_relative_paths(self):
+ """Provide a list of all relative paths in this directory. Includes
+ directories only if they are empty.
+
+ Yields:
+ (List(str)) - list of all files with relative paths.
+
+ """
+ raise NotImplementedError()