comparison mercurial/revlog.py @ 41202:e7a2cc84dbc0

revlog: always enable generaldelta on version 2 revlogs

This commit starts the process of diverging version 2 revlogs
from version 1 revlogs.

generaldelta is a useful feature and has been enabled by
default for ages. I can't think of a good reason why the
feature should be disabled. Yes, it is true changelogs
today don't have generaldelta enabled. But that's because
they don't have delta chains enabled, so generaldelta makes
no sense there.

This commit makes generaldelta always enabled on version 2
revlogs.

As part of this, one-off code in changelog.py mucking with
revlog.version had to be made conditional on the revlog
version, as we don't want to change revlog feature
flags on version 2 revlogs. The fact this code exists
is horrible and stems from revlog options being shared by
the opener. We probably want a better API here. But that can
wait for another patch.

Differential Revision: https://phab.mercurial-scm.org/D5561

41201:6439cefaeb64

        mmapindexthreshold = None
        opts = getattr(opener, 'options', {}) or {}

        if 'revlogv2' in opts:
            # version 2 revlogs always use generaldelta.
            versionflags = REVLOGV2 | FLAG_GENERALDELTA | FLAG_INLINE_DATA
        elif 'revlogv1' in opts:
            versionflags = REVLOGV1 | FLAG_INLINE_DATA
            if 'generaldelta' in opts:
                versionflags |= FLAG_GENERALDELTA
        else:

        except IOError as inst:
            if inst.errno != errno.ENOENT:
                raise

        self.version = versionflags
        self._inline = versionflags & FLAG_INLINE_DATA
        self._generaldelta = versionflags & FLAG_GENERALDELTA
        flags = versionflags & ~0xFFFF
        fmt = versionflags & 0xFFFF
        if fmt == REVLOGV0:
            if flags:
                raise error.RevlogError(_('unknown flags (%#04x) in version %d '
                                          'revlog %s') %
                                        (flags >> 16, fmt, self.indexfile))
        elif fmt == REVLOGV1:
            if flags & ~REVLOGV1_FLAGS:
                raise error.RevlogError(_('unknown flags (%#04x) in version %d '
                                          'revlog %s') %
                                        (flags >> 16, fmt, self.indexfile))
        elif fmt == REVLOGV2:
            if flags & ~REVLOGV2_FLAGS:
                raise error.RevlogError(_('unknown flags (%#04x) in version %d '
                                          'revlog %s') %
                                        (flags >> 16, fmt, self.indexfile))
        else:
            raise error.RevlogError(_('unknown version (%d) in revlog %s') %
                                    (fmt, self.indexfile))

        self._storedeltachains = True

41202:e7a2cc84dbc0

        mmapindexthreshold = None
        opts = getattr(opener, 'options', {}) or {}

        if 'revlogv2' in opts:
            versionflags = REVLOGV2 | FLAG_INLINE_DATA
        elif 'revlogv1' in opts:
            versionflags = REVLOGV1 | FLAG_INLINE_DATA
            if 'generaldelta' in opts:
                versionflags |= FLAG_GENERALDELTA
        else:

        except IOError as inst:
            if inst.errno != errno.ENOENT:
                raise

        self.version = versionflags

        flags = versionflags & ~0xFFFF
        fmt = versionflags & 0xFFFF

        if fmt == REVLOGV0:
            if flags:
                raise error.RevlogError(_('unknown flags (%#04x) in version %d '
                                          'revlog %s') %
                                        (flags >> 16, fmt, self.indexfile))

            self._inline = False
            self._generaldelta = False

        elif fmt == REVLOGV1:
            if flags & ~REVLOGV1_FLAGS:
                raise error.RevlogError(_('unknown flags (%#04x) in version %d '
                                          'revlog %s') %
                                        (flags >> 16, fmt, self.indexfile))

            self._inline = versionflags & FLAG_INLINE_DATA
            self._generaldelta = versionflags & FLAG_GENERALDELTA

        elif fmt == REVLOGV2:
            if flags & ~REVLOGV2_FLAGS:
                raise error.RevlogError(_('unknown flags (%#04x) in version %d '
                                          'revlog %s') %
                                        (flags >> 16, fmt, self.indexfile))

            self._inline = versionflags & FLAG_INLINE_DATA
            # generaldelta implied by version 2 revlogs.
            self._generaldelta = True

        else:
            raise error.RevlogError(_('unknown version (%d) in revlog %s') %
                                    (fmt, self.indexfile))

        self._storedeltachains = True