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# Copyright (C) 2005 by Canonical Development Ltd
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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An implementation the primary storage type CompressedTextStore.
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This store keeps compressed versions of the full text. It does not
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do any sort of delta compression.
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import os, tempfile, gzip
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from bzrlib.trace import mutter
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from bzrlib.errors import BzrError
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from StringIO import StringIO
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from stat import ST_SIZE
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class CompressedTextStore(bzrlib.store.TransportStore):
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"""Store that holds files indexed by unique names.
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Files can be added, but not modified once they are in. Typically
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the hash is used as the name, or something else known to be unique,
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Files are stored gzip compressed, with no delta compression.
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>>> st = ScratchCompressedTextStore()
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>>> st.add(StringIO('hello'), 'aa')
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You are not allowed to add an id that is already present.
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Entries can be retrieved as files, which may then be read.
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>>> st.add(StringIO('goodbye'), '123123')
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>>> st['123123'].read()
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def __init__(self, transport):
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super(CompressedTextStore, self).__init__(transport)
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def _check_fileid(self, fileid):
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if '\\' in fileid or '/' in fileid:
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raise ValueError("invalid store id %r" % fileid)
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def _relpath(self, fileid):
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self._check_fileid(fileid)
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def add(self, f, fileid):
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"""Add contents of a file into the store.
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f -- An open file, or file-like object."""
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# TODO: implement an add_multi which can do some of it's
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# own piplelining, and possible take advantage of
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# transport.put_multi(). The problem is that
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# entries potentially need to be compressed as they
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# are received, which implies translation, which
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# means it isn't as straightforward as we would like.
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from cStringIO import StringIO
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from bzrlib.osutils import pumpfile
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mutter("add store entry %r" % (fileid))
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if isinstance(f, basestring):
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fn = self._relpath(fileid)
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if self._transport.has(fn):
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raise BzrError("store %r already contains id %r" % (self._transport.base, fileid))
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gf = gzip.GzipFile(mode='wb', fileobj=sio)
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# if pumpfile handles files that don't fit in ram,
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# so will this function
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if isinstance(f, basestring):
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self._transport.put(fn, sio)
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def _do_copy(self, other, to_copy, pb, permit_failure=False):
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if isinstance(other, CompressedTextStore):
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return self._copy_multi_text(other, to_copy, pb,
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permit_failure=permit_failure)
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return super(CompressedTextStore, self)._do_copy(other, to_copy,
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pb, permit_failure=permit_failure)
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def _copy_multi_text(self, other, to_copy, pb,
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permit_failure=False):
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# Because of _transport, we can no longer assume
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# that they are on the same filesystem, we can, however
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# assume that we only need to copy the exact bytes,
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# we don't need to process the files.
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for fileid, has in zip(to_copy, other.has(to_copy)):
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new_to_copy.add(fileid)
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to_copy = new_to_copy
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#mutter('_copy_multi_text copying %s, failed %s' % (to_copy, failed))
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paths = [self._relpath(fileid) for fileid in to_copy]
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count = other._transport.copy_to(paths, self._transport, pb=pb)
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assert count == len(to_copy)
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def __contains__(self, fileid):
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fn = self._relpath(fileid)
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return self._transport.has(fn)
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def has(self, fileids, pb=None):
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"""Return True/False for each entry in fileids.
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:param fileids: A List or generator yielding file ids.
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:return: A generator or list returning True/False for each entry.
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relpaths = (self._relpath(fid) for fid in fileids)
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return self._transport.has_multi(relpaths, pb=pb)
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def get(self, fileids, permit_failure=False, pb=None):
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"""Return a set of files, one for each requested entry.
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TODO: Write some tests to make sure that permit_failure is
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TODO: What should the exception be for a missing file?
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KeyError, or NoSuchFile?
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# This next code gets a bit hairy because it can allow
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# to not request a file which doesn't seem to exist.
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# Also, the same fileid may be requested twice, so we
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# can't just build up a map.
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rel_paths = [self._relpath(fid) for fid in fileids]
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#mutter('CompressedTextStore.get(permit_failure=%s)' % permit_failure)
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for path, has in zip(rel_paths,
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self._transport.has_multi(rel_paths)):
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existing_paths.append(path)
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is_requested.append(True)
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is_requested.append(False)
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#mutter('Retrieving %s out of %s' % (existing_paths, rel_paths))
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#mutter('Retrieving all %s' % (rel_paths, ))
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existing_paths = rel_paths
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is_requested = [True for x in rel_paths]
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for f in self._transport.get_multi(existing_paths, pb=pb):
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assert count < len(is_requested)
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while not is_requested[count]:
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if hasattr(f, 'tell'):
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yield gzip.GzipFile(mode='rb', fileobj=f)
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from cStringIO import StringIO
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sio = StringIO(f.read())
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yield gzip.GzipFile(mode='rb', fileobj=sio)
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while count < len(is_requested):
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# TODO: case-insensitive?
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for f in self._transport.list_dir('.'):
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return len([f for f in self._transport.list_dir('.')])
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def __getitem__(self, fileid):
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"""Returns a file reading from a particular entry."""
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fn = self._relpath(fileid)
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# This will throw if the file doesn't exist.
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f = self._transport.get(fn)
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raise KeyError('This store (%s) does not contain %s' % (self, fileid))
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# gzip.GzipFile.read() requires a tell() function
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# but some transports return objects that cannot seek
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# so buffer them in a StringIO instead
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if hasattr(f, 'tell'):
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return gzip.GzipFile(mode='rb', fileobj=f)
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from cStringIO import StringIO
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sio = StringIO(f.read())
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return gzip.GzipFile(mode='rb', fileobj=sio)
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def total_size(self):
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"""Return (count, bytes)
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This is the (compressed) size stored on disk, not the size of
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relpaths = [self._relpath(fid) for fid in self]
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for st in self._transport.stat_multi(relpaths):
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class ScratchCompressedTextStore(CompressedTextStore):
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"""Self-destructing test subclass of CompressedTextStore.
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The Store only exists for the lifetime of the Python object.
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Obviously you should not put anything precious in it.
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from transport import transport
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t = transport(tempfile.mkdtemp())
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super(ScratchCompressedTextStore, self).__init__(t)
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self._transport.delete_multi(self._transport.list_dir('.'))
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os.rmdir(self._transport.base)
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mutter("%r destroyed" % self)
added
removed
bzrlib/store/compressed_text.py
