comparison mercurial/store.py @ 47234:616b8f412676

revlogv2: introduce a very basic docket file

This is the first stone toward using a docket file in revlogv2. Right now the
docket is very basic and only store the version number (which is -also- stored
into the index file…) and the other files have fixed name. This new
implementation break transactionally… but they are no test checking
transactionally for revlogv2… So I take this as an opportunity to start small.
They are no usage of revlogv2 outside of tests anyway.

The docket keeps the `.i` naming used by previous version index to preserve a
unique entry point. We could decide to use a different name and look it up
first, or to fully rework this in a future "store" version. However that does
not seems necessary right now.

We will re-introduces transactionality (and associated testing…) in a later
changesets.


A long list of TODOs have been added to the relevant comment.

Differential Revision: https://phab.mercurial-scm.org/D10624

47233:bcafcd779d2e

    b'obsstore',
    b'requires',
]

REVLOG_FILES_MAIN_EXT = (b'.i', b'i.tmpcensored')
REVLOG_FILES_OTHER_EXT = (b'.d', b'.n', b'.nd', b'd.tmpcensored')
# files that are "volatile" and might change between listing and streaming
#
# note: the ".nd" file are nodemap data and won't "change" but they might be
# deleted.
REVLOG_FILES_VOLATILE_EXT = (b'.n', b'.nd')

# some exception to the above matching
EXCLUDED = re.compile(b'.*undo\.[^/]+\.nd?$')


def is_revlog(f, kind, st):
    if kind != stat.S_IFREG:
        return None
    return revlog_type(f)


def revlog_type(f):
    if f.endswith(REVLOG_FILES_MAIN_EXT):
        return FILEFLAGS_REVLOG_MAIN
    elif f.endswith(REVLOG_FILES_OTHER_EXT) and EXCLUDED.match(f) is None:
        t = FILETYPE_FILELOG_OTHER
        if f.endswith(REVLOG_FILES_VOLATILE_EXT):
            t |= FILEFLAGS_VOLATILE

47234:616b8f412676

    b'obsstore',
    b'requires',
]

REVLOG_FILES_MAIN_EXT = (b'.i', b'i.tmpcensored')
REVLOG_FILES_OTHER_EXT = (b'.idx', b'.d', b'.n', b'.nd', b'd.tmpcensored')
# files that are "volatile" and might change between listing and streaming
#
# note: the ".nd" file are nodemap data and won't "change" but they might be
# deleted.
REVLOG_FILES_VOLATILE_EXT = (b'.n', b'.nd')

# some exception to the above matching
EXCLUDED = re.compile(b'.*undo\.[^/]+\.(nd?|i)$')


def is_revlog(f, kind, st):
    if kind != stat.S_IFREG:
        return None
    return revlog_type(f)


def revlog_type(f):
    if f.endswith(REVLOG_FILES_MAIN_EXT) and EXCLUDED.match(f) is None:
        return FILEFLAGS_REVLOG_MAIN
    elif f.endswith(REVLOG_FILES_OTHER_EXT) and EXCLUDED.match(f) is None:
        t = FILETYPE_FILELOG_OTHER
        if f.endswith(REVLOG_FILES_VOLATILE_EXT):
            t |= FILEFLAGS_VOLATILE