mercurial/revlogutils/revlogv0.py
author Pierre-Yves David <pierre-yves.david@octobus.net>
Thu, 07 Mar 2024 04:15:23 +0100
changeset 51536 718f28ea3af4
parent 49284 d44e3c45f0e4
permissions -rw-r--r--
branchcache: add a "pure topological head" fast path In a narrow but actually quick common case, all topological heads are all on the same branch and all open. In this case, computing the branch map is very simple. We can quickly detect situation where this situation will not change. So we update the V3 format to be able to express this situation and upgrade the update code to detect we remains in that mode. The branch cache is populated with the actual value when the branch map is accessed, but the update_disk method can do the update without needing to populate it.

# revlogv0 - code related to revlog format "V0"
#
# Copyright 2005-2007 Olivia Mackall <olivia@selenic.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.


from ..node import sha1nodeconstants
from .constants import (
    INDEX_ENTRY_V0,
)
from ..i18n import _

from .. import (
    error,
    node,
    revlogutils,
    util,
)

from . import (
    nodemap as nodemaputil,
)


def getoffset(q):
    return int(q >> 16)


def gettype(q):
    return int(q & 0xFFFF)


class revlogoldindex(list):
    rust_ext_compat = 0
    entry_size = INDEX_ENTRY_V0.size
    null_item = revlogutils.entry(
        data_offset=0,
        data_compressed_length=0,
        data_delta_base=node.nullrev,
        link_rev=node.nullrev,
        parent_rev_1=node.nullrev,
        parent_rev_2=node.nullrev,
        node_id=sha1nodeconstants.nullid,
    )

    @util.propertycache
    def _nodemap(self):
        nodemap = nodemaputil.NodeMap({sha1nodeconstants.nullid: node.nullrev})
        for r in range(0, len(self)):
            n = self[r][7]
            nodemap[n] = r
        return nodemap

    def has_node(self, node):
        """return True if the node exist in the index"""
        return node in self._nodemap

    def rev(self, node):
        """return a revision for a node

        If the node is unknown, raise a RevlogError"""
        return self._nodemap[node]

    def get_rev(self, node):
        """return a revision for a node

        If the node is unknown, return None"""
        return self._nodemap.get(node)

    def append(self, tup):
        self._nodemap[tup[7]] = len(self)
        super(revlogoldindex, self).append(tup)

    def __delitem__(self, i):
        if not isinstance(i, slice) or not i.stop == -1 or i.step is not None:
            raise ValueError(b"deleting slices only supports a:-1 with step 1")
        for r in range(i.start, len(self)):
            del self._nodemap[self[r][7]]
        super(revlogoldindex, self).__delitem__(i)

    def clearcaches(self):
        self.__dict__.pop('_nodemap', None)

    def __getitem__(self, i):
        if i == -1:
            return self.null_item
        return list.__getitem__(self, i)

    def pack_header(self, header):
        """pack header information in binary"""
        return b''

    def entry_binary(self, rev):
        """return the raw binary string representing a revision"""
        entry = self[rev]
        if gettype(entry[0]):
            raise error.RevlogError(
                _(b'index entry flags need revlog version 1')
            )
        e2 = (
            getoffset(entry[0]),
            entry[1],
            entry[3],
            entry[4],
            self[entry[5]][7],
            self[entry[6]][7],
            entry[7],
        )
        return INDEX_ENTRY_V0.pack(*e2)


def parse_index_v0(data, inline):
    s = INDEX_ENTRY_V0.size
    index = []
    nodemap = nodemaputil.NodeMap({node.nullid: node.nullrev})
    n = off = 0
    l = len(data)
    while off + s <= l:
        cur = data[off : off + s]
        off += s
        e = INDEX_ENTRY_V0.unpack(cur)
        # transform to revlogv1 format
        e2 = revlogutils.entry(
            data_offset=e[0],
            data_compressed_length=e[1],
            data_delta_base=e[2],
            link_rev=e[3],
            parent_rev_1=nodemap.get(e[4], node.nullrev),
            parent_rev_2=nodemap.get(e[5], node.nullrev),
            node_id=e[6],
        )
        index.append(e2)
        nodemap[e[6]] = n
        n += 1

    index = revlogoldindex(index)
    return index, None