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Editing: loose.py
# Copyright (C) 2010, 2011 Sebastian Thiel (byronimo@gmail.com) and contributors # # This module is part of GitDB and is released under # the New BSD License: http://www.opensource.org/licenses/bsd-license.php from gitdb.db.base import ( FileDBBase, ObjectDBR, ObjectDBW ) from gitdb.exc import ( BadObject, AmbiguousObjectName ) from gitdb.stream import ( DecompressMemMapReader, FDCompressedSha1Writer, FDStream, Sha1Writer ) from gitdb.base import ( OStream, OInfo ) from gitdb.util import ( file_contents_ro_filepath, ENOENT, hex_to_bin, bin_to_hex, exists, chmod, isdir, isfile, remove, mkdir, rename, dirname, basename, join ) from gitdb.fun import ( chunk_size, loose_object_header_info, write_object, stream_copy ) from gitdb.utils.encoding import force_bytes import tempfile import os import sys __all__ = ('LooseObjectDB', ) class LooseObjectDB(FileDBBase, ObjectDBR, ObjectDBW): """A database which operates on loose object files""" # CONFIGURATION # chunks in which data will be copied between streams stream_chunk_size = chunk_size # On windows we need to keep it writable, otherwise it cannot be removed # either new_objects_mode = int("444", 8) if os.name == 'nt': new_objects_mode = int("644", 8) def __init__(self, root_path): super().__init__(root_path) self._hexsha_to_file = dict() # Additional Flags - might be set to 0 after the first failure # Depending on the root, this might work for some mounts, for others not, which # is why it is per instance self._fd_open_flags = getattr(os, 'O_NOATIME', 0) #{ Interface def object_path(self, hexsha): """ :return: path at which the object with the given hexsha would be stored, relative to the database root""" return join(hexsha[:2], hexsha[2:]) def readable_db_object_path(self, hexsha): """ :return: readable object path to the object identified by hexsha :raise BadObject: If the object file does not exist""" try: return self._hexsha_to_file[hexsha] except KeyError: pass # END ignore cache misses # try filesystem path = self.db_path(self.object_path(hexsha)) if exists(path): self._hexsha_to_file[hexsha] = path return path # END handle cache raise BadObject(hexsha) def partial_to_complete_sha_hex(self, partial_hexsha): """:return: 20 byte binary sha1 string which matches the given name uniquely :param name: hexadecimal partial name (bytes or ascii string) :raise AmbiguousObjectName: :raise BadObject: """ candidate = None for binsha in self.sha_iter(): if bin_to_hex(binsha).startswith(force_bytes(partial_hexsha)): # it can't ever find the same object twice if candidate is not None: raise AmbiguousObjectName(partial_hexsha) candidate = binsha # END for each object if candidate is None: raise BadObject(partial_hexsha) return candidate #} END interface def _map_loose_object(self, sha): """ :return: memory map of that file to allow random read access :raise BadObject: if object could not be located""" db_path = self.db_path(self.object_path(bin_to_hex(sha))) try: return file_contents_ro_filepath(db_path, flags=self._fd_open_flags) except OSError as e: if e.errno != ENOENT: # try again without noatime try: return file_contents_ro_filepath(db_path) except OSError as new_e: raise BadObject(sha) from new_e # didn't work because of our flag, don't try it again self._fd_open_flags = 0 else: raise BadObject(sha) from e # END handle error # END exception handling def set_ostream(self, stream): """:raise TypeError: if the stream does not support the Sha1Writer interface""" if stream is not None and not isinstance(stream, Sha1Writer): raise TypeError("Output stream musst support the %s interface" % Sha1Writer.__name__) return super().set_ostream(stream) def info(self, sha): m = self._map_loose_object(sha) try: typ, size = loose_object_header_info(m) return OInfo(sha, typ, size) finally: if hasattr(m, 'close'): m.close() # END assure release of system resources def stream(self, sha): m = self._map_loose_object(sha) type, size, stream = DecompressMemMapReader.new(m, close_on_deletion=True) return OStream(sha, type, size, stream) def has_object(self, sha): try: self.readable_db_object_path(bin_to_hex(sha)) return True except BadObject: return False # END check existence def store(self, istream): """note: The sha we produce will be hex by nature""" tmp_path = None writer = self.ostream() if writer is None: # open a tmp file to write the data to fd, tmp_path = tempfile.mkstemp(prefix='obj', dir=self._root_path) if istream.binsha is None: writer = FDCompressedSha1Writer(fd) else: writer = FDStream(fd) # END handle direct stream copies # END handle custom writer try: try: if istream.binsha is not None: # copy as much as possible, the actual uncompressed item size might # be smaller than the compressed version stream_copy(istream.read, writer.write, sys.maxsize, self.stream_chunk_size) else: # write object with header, we have to make a new one write_object(istream.type, istream.size, istream.read, writer.write, chunk_size=self.stream_chunk_size) # END handle direct stream copies finally: if tmp_path: writer.close() # END assure target stream is closed except: if tmp_path: os.remove(tmp_path) raise # END assure tmpfile removal on error hexsha = None if istream.binsha: hexsha = istream.hexsha else: hexsha = writer.sha(as_hex=True) # END handle sha if tmp_path: obj_path = self.db_path(self.object_path(hexsha)) obj_dir = dirname(obj_path) if not isdir(obj_dir): mkdir(obj_dir) # END handle destination directory # rename onto existing doesn't work on NTFS if isfile(obj_path): remove(tmp_path) else: rename(tmp_path, obj_path) # end rename only if needed # make sure its readable for all ! It started out as rw-- tmp file # but needs to be rwrr chmod(obj_path, self.new_objects_mode) # END handle dry_run istream.binsha = hex_to_bin(hexsha) return istream def sha_iter(self): # find all files which look like an object, extract sha from there for root, dirs, files in os.walk(self.root_path()): root_base = basename(root) if len(root_base) != 2: continue for f in files: if len(f) != 38: continue yield hex_to_bin(root_base + f) # END for each file # END for each walk iteration def size(self): return len(tuple(self.sha_iter()))
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