# Copyright (C) 2005 by Canonical Development Ltd # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 2 of the License, or # (at your option) any later version. # This program 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 General Public License for more details. # You should have received a copy of the GNU General Public License # along with this program; if not, write to the Free Software # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA """ Stores are the main data-storage mechanism for Bazaar-NG. A store is a simple write-once container indexed by a universally unique ID. """ import os, tempfile, types, osutils, gzip, errno from stat import ST_SIZE from StringIO import StringIO from bzrlib.errors import BzrError from bzrlib.trace import mutter import bzrlib.ui ###################################################################### # stores class StoreError(Exception): pass class ImmutableStore(object): """Store that holds files indexed by unique names. Files can be added, but not modified once they are in. Typically the hash is used as the name, or something else known to be unique, such as a UUID. >>> st = ImmutableScratchStore() >>> st.add(StringIO('hello'), 'aa') >>> 'aa' in st True >>> 'foo' in st False You are not allowed to add an id that is already present. Entries can be retrieved as files, which may then be read. >>> st.add(StringIO('goodbye'), '123123') >>> st['123123'].read() 'goodbye' TODO: Atomic add by writing to a temporary file and renaming. In bzr 0.0.5 and earlier, files within the store were marked readonly on disk. This is no longer done but existing stores need to be accomodated. """ def __init__(self, basedir): self._basedir = basedir def _path(self, entry_id): if not isinstance(entry_id, basestring): raise TypeError(type(entry_id)) if '\\' in entry_id or '/' in entry_id: raise ValueError("invalid store id %r" % entry_id) return os.path.join(self._basedir, entry_id) def __repr__(self): return "%s(%r)" % (self.__class__.__name__, self._basedir) def add(self, f, fileid, compressed=True): """Add contents of a file into the store. f -- An open file, or file-like object.""" # FIXME: Only works on files that will fit in memory from bzrlib.atomicfile import AtomicFile mutter("add store entry %r" % (fileid)) if isinstance(f, types.StringTypes): content = f else: content = f.read() p = self._path(fileid) if os.access(p, os.F_OK) or os.access(p + '.gz', os.F_OK): raise BzrError("store %r already contains id %r" % (self._basedir, fileid)) fn = p if compressed: fn = fn + '.gz' af = AtomicFile(fn, 'wb') try: if compressed: gf = gzip.GzipFile(mode='wb', fileobj=af) gf.write(content) gf.close() else: af.write(content) af.commit() finally: af.close() def copy_multi(self, other, ids, permit_failure=False): """Copy texts for ids from other into self. If an id is present in self, it is skipped. Returns (count_copied, failed), where failed is a collection of ids that could not be copied. """ pb = bzrlib.ui.ui_factory.progress_bar() pb.update('preparing to copy') to_copy = [id for id in ids if id not in self] if isinstance(other, ImmutableStore): return self.copy_multi_immutable(other, to_copy, pb) count = 0 failed = set() for id in to_copy: count += 1 pb.update('copy', count, len(to_copy)) if not permit_failure: self.add(other[id], id) else: try: entry = other[id] except IndexError: failed.add(id) continue self.add(entry, id) if not permit_failure: assert count == len(to_copy) pb.clear() return count, failed def copy_multi_immutable(self, other, to_copy, pb, permit_failure=False): from shutil import copyfile count = 0 failed = set() for id in to_copy: p = self._path(id) other_p = other._path(id) try: copyfile(other_p, p) except IOError, e: if e.errno == errno.ENOENT: if not permit_failure: copyfile(other_p+".gz", p+".gz") else: try: copyfile(other_p+".gz", p+".gz") except IOError, e: if e.errno == errno.ENOENT: failed.add(id) else: raise else: raise count += 1 pb.update('copy', count, len(to_copy)) assert count == len(to_copy) pb.clear() return count, failed def __contains__(self, fileid): """""" p = self._path(fileid) return (os.access(p, os.R_OK) or os.access(p + '.gz', os.R_OK)) # TODO: Guard against the same thing being stored twice, compressed and uncompresse def __iter__(self): for f in os.listdir(self._basedir): if f[-3:] == '.gz': # TODO: case-insensitive? yield f[:-3] else: yield f def __len__(self): return len(os.listdir(self._basedir)) def __getitem__(self, fileid): """Returns a file reading from a particular entry.""" p = self._path(fileid) try: return gzip.GzipFile(p + '.gz', 'rb') except IOError, e: if e.errno != errno.ENOENT: raise try: return file(p, 'rb') except IOError, e: if e.errno != errno.ENOENT: raise raise IndexError(fileid) def total_size(self): """Return (count, bytes) This is the (compressed) size stored on disk, not the size of the content.""" total = 0 count = 0 for fid in self: count += 1 p = self._path(fid) try: total += os.stat(p)[ST_SIZE] except OSError: total += os.stat(p + '.gz')[ST_SIZE] return count, total class ImmutableScratchStore(ImmutableStore): """Self-destructing test subclass of ImmutableStore. The Store only exists for the lifetime of the Python object. Obviously you should not put anything precious in it. """ def __init__(self): ImmutableStore.__init__(self, tempfile.mkdtemp()) def __del__(self): for f in os.listdir(self._basedir): fpath = os.path.join(self._basedir, f) # needed on windows, and maybe some other filesystems os.chmod(fpath, 0600) os.remove(fpath) os.rmdir(self._basedir) mutter("%r destroyed" % self)