diff options
Diffstat (limited to 'git/db/py/mem.py')
| -rw-r--r-- | git/db/py/mem.py | 65 |
1 files changed, 33 insertions, 32 deletions
diff --git a/git/db/py/mem.py b/git/db/py/mem.py index 63ceb756..65a457fe 100644 --- a/git/db/py/mem.py +++ b/git/db/py/mem.py @@ -4,72 +4,74 @@ # the New BSD License: http://www.opensource.org/licenses/bsd-license.php """Contains the MemoryDatabase implementation""" from base import ( - PureObjectDBR, - PureObjectDBW - ) + PureObjectDBR, + PureObjectDBW +) from loose import PureLooseObjectODB from git.base import ( - OStream, - IStream, - ) + OStream, + IStream, +) from git.exc import ( - BadObject, - UnsupportedOperation - ) + BadObject, + UnsupportedOperation +) from git.stream import ( - ZippedStoreShaWriter, - DecompressMemMapReader, - ) + ZippedStoreShaWriter, + DecompressMemMapReader, +) from cStringIO import StringIO __all__ = ("PureMemoryDB", ) + class PureMemoryDB(PureObjectDBR, PureObjectDBW): + """A memory database stores everything to memory, providing fast IO and object retrieval. It should be used to buffer results and obtain SHAs before writing it to the actual physical storage, as it allows to query whether object already exists in the target storage before introducing actual IO - + :note: memory is currently not threadsafe, hence the async methods cannot be used for storing""" - + def __init__(self): super(PureMemoryDB, self).__init__() self._db = PureLooseObjectODB("path/doesnt/matter") - + # maps 20 byte shas to their OStream objects self._cache = dict() - + def set_ostream(self, stream): raise UnsupportedOperation("PureMemoryDB's always stream into memory") - + def store(self, istream): zstream = ZippedStoreShaWriter() self._db.set_ostream(zstream) - + istream = self._db.store(istream) zstream.close() # close to flush zstream.seek(0) - - # don't provide a size, the stream is written in object format, hence the + + # don't provide a size, the stream is written in object format, hence the # header needs decompression - decomp_stream = DecompressMemMapReader(zstream.getvalue(), close_on_deletion=False) + decomp_stream = DecompressMemMapReader(zstream.getvalue(), close_on_deletion=False) self._cache[istream.binsha] = OStream(istream.binsha, istream.type, istream.size, decomp_stream) - + return istream - + def store_async(self, reader): raise UnsupportedOperation("PureMemoryDBs cannot currently be used for async write access") - + def has_object(self, sha): return sha in self._cache def info(self, sha): # we always return streams, which are infos as well return self.stream(sha) - + def stream(self, sha): try: ostream = self._cache[sha] @@ -79,15 +81,14 @@ class PureMemoryDB(PureObjectDBR, PureObjectDBW): except KeyError: raise BadObject(sha) # END exception handling - + def size(self): return len(self._cache) - + def sha_iter(self): return self._cache.iterkeys() - - - #{ Interface + + #{ Interface def stream_copy(self, sha_iter, odb): """Copy the streams as identified by sha's yielded by sha_iter into the given odb The streams will be copied directly @@ -99,12 +100,12 @@ class PureMemoryDB(PureObjectDBR, PureObjectDBW): if odb.has_object(sha): continue # END check object existance - + ostream = self.stream(sha) # compressed data including header sio = StringIO(ostream.stream.data()) istream = IStream(ostream.type, ostream.size, sio, sha) - + odb.store(istream) count += 1 # END for each sha |