marmoute updated this revision to Diff 19784. REPOSITORY rHG Mercurial
CHANGES SINCE LAST UPDATE https://phab.mercurial-scm.org/D7838?vs=19754&id=19784 CHANGES SINCE LAST ACTION https://phab.mercurial-scm.org/D7838/new/ REVISION DETAIL https://phab.mercurial-scm.org/D7838 AFFECTED FILES mercurial/revlogutils/nodemap.py tests/test-persistent-nodemap.t CHANGE DETAILS diff --git a/tests/test-persistent-nodemap.t b/tests/test-persistent-nodemap.t --- a/tests/test-persistent-nodemap.t +++ b/tests/test-persistent-nodemap.t @@ -10,6 +10,8 @@ > exp-persistent-nodemap=yes > EOF $ hg debugbuilddag .+5000 + $ f --size .hg/store/00changelog.n + .hg/store/00changelog.n: size=18 $ hg debugnodemap --dump-new | f --sha256 --size size=245760, sha256=bc400bf49f11e83bbd25630439feee6628a80a8602d2e38972eac44cc3efe10c $ hg debugnodemap --dump-disk | f --sha256 --bytes=256 --hexdump --size diff --git a/mercurial/revlogutils/nodemap.py b/mercurial/revlogutils/nodemap.py --- a/mercurial/revlogutils/nodemap.py +++ b/mercurial/revlogutils/nodemap.py @@ -8,6 +8,7 @@ from __future__ import absolute_import +import os import struct from .. import ( @@ -26,7 +27,20 @@ """read the nodemap for a revlog from disk""" if revlog.nodemap_file is None: return None - return revlog.opener.tryread(revlog.nodemap_file) + pdata = revlog.opener.tryread(revlog.nodemap_file) + if not pdata: + return None + offset = 0 + (version,) = S_VERSION.unpack(pdata[offset : offset + S_VERSION.size]) + if version != ONDISK_VERSION: + return None + offset += S_VERSION.size + (uuid_size,) = S_HEADER.unpack(pdata[offset : offset + S_HEADER.size]) + offset += S_HEADER.size + uid = pdata[offset : offset + uuid_size] + + filename = _rawdata_filepath(revlog, uid) + return revlog.opener.tryread(filename) def setup_persistent_nodemap(tr, revlog): @@ -55,13 +69,71 @@ msg = "calling persist nodemap on a revlog without the feature enableb" raise error.ProgrammingError(msg) data = persistent_data(revlog.index) + uid = _make_uid() + datafile = _rawdata_filepath(revlog, uid) + # EXP-TODO: if this is a cache, this should use a cache vfs, not a + # store vfs + with revlog.opener(datafile, b'w') as fd: + fd.write(data) # EXP-TODO: if this is a cache, this should use a cache vfs, not a # store vfs - with revlog.opener(revlog.nodemap_file, b'w') as f: - f.write(data) + with revlog.opener(revlog.nodemap_file, b'w', atomictemp=True) as fp: + fp.write(_serialize_docket(uid)) # EXP-TODO: if the transaction abort, we should remove the new data and - # reinstall the old one. (This will be simpler when the file format get a - # bit more advanced) + # reinstall the old one. + + +### Nodemap docket file +# +# The nodemap data are stored on disk using 2 files: +# +# * a raw data files containing a persistent nodemap +# (see `Nodemap Trie` section) +# +# * a small "docket" file containing medatadata +# +# While the nodemap data can be multiple tens of megabytes, the "docket" is +# small, it is easy to update it automatically or to duplicated its content +# during a transaction. +# +# Multiple raw data can exist at the same time (The currently valid one and a +# new one beind used by an in progress transaction). To accomodate this, the +# filename hosting the raw data has a variable parts. The exact filename is +# specified inside the "docket" file. +# +# The docket file contains information to find, qualify and validate the raw +# data. Its content is currently very light, but it will expand as the on disk +# nodemap gains the necessary features to be used in production. + +# version 0 is experimental, no BC garantee, do no use outside of tests. +ONDISK_VERSION = 0 + +S_VERSION = struct.Struct(">B") +S_HEADER = struct.Struct(">B") + +ID_SIZE = 8 + + +def _make_uid(): + """return a new unique identifier. + + The identifier is random and composed of ascii characters.""" + return nodemod.hex(os.urandom(ID_SIZE)) + + +def _serialize_docket(uid): + """return serialized bytes for a docket using the passed uid""" + data = [] + data.append(S_VERSION.pack(ONDISK_VERSION)) + data.append(S_HEADER.pack(len(uid))) + data.append(uid) + return b''.join(data) + + +def _rawdata_filepath(revlog, uid): + """The (vfs relative) nodemap's rawdata file for a given uid""" + prefix = revlog.nodemap_file[:-2] + return b"%s-%s.nd" % (prefix, uid) ### Nodemap Trie To: marmoute, #hg-reviewers Cc: mercurial-devel _______________________________________________ Mercurial-devel mailing list Mercurial-devel@mercurial-scm.org https://www.mercurial-scm.org/mailman/listinfo/mercurial-devel
