view mercurial/config.py @ 39646:9c2c77c73f23

wireprotov2: define and implement "changesetdata" command

This commit introduces the "changesetdata" wire protocol command.
The role of the command is to expose data associated with changelog
revisions, including the raw revision data itself.

This command is the first piece of a new clone/pull strategy that
is built on top of domain-specific commands for data retrieval.
Instead of a monolithic "getbundle" command that transfers all of the
things, we'll be introducing commands for fetching specific pieces
of data.

Since the changeset is the fundamental unit from which we derive
pointers to other data (manifests, file nodes, etc), it makes sense
to start reimplementing pull with this data.

The command accepts as arguments a set of root and head revisions
defining the changesets that should be fetched as well as an explicit
list of nodes. By default, the command returns only the node values:
the client must explicitly request additional fields be added to the
response. Current supported fields are the list of parent nodes and
the revision fulltext.

My plan is to eventually add support for transferring other data
associated with changesets, including phases, bookmarks, obsolescence
markers, etc. Since the response format is CBOR, we'll be able to add
this data into the response object relatively easily (it should be
as simple as adding a key in a map).

The documentation captures a number of TODO items. Some of these may
require BC breaking changes. That's fine: wire protocol v2 is still
highly experimental.

Differential Revision: https://phab.mercurial-scm.org/D4481

# config.py - configuration parsing for Mercurial
#
#  Copyright 2009 Matt Mackall <[e-mail]> and others
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

import errno
import os

from .i18n import _
from . import (
    error,
    pycompat,
    util,
)

class config(object):
    def __init__(self, data=None, includepaths=None):
        self._data = {}
        self._unset = []
        self._includepaths = includepaths or []
        if data:
            for k in data._data:
                self._data[k] = data[k].copy()
            self._source = data._source.copy()
        else:
            self._source = util.cowdict()
    def copy(self):
        return config(self)
    def __contains__(self, section):
        return section in self._data
    def hasitem(self, section, item):
        return item in self._data.get(section, {})
    def __getitem__(self, section):
        return self._data.get(section, {})
    def __iter__(self):
        for d in self.sections():
            yield d
    def update(self, src):
        self._source = self._source.preparewrite()
        for s, n in src._unset:
            ds = self._data.get(s, None)
            if ds is not None and n in ds:
                self._data[s] = ds.preparewrite()
                del self._data[s][n]
                del self._source[(s, n)]
        for s in src:
            ds = self._data.get(s, None)
            if ds:
                self._data[s] = ds.preparewrite()
            else:
                self._data[s] = util.cowsortdict()
            self._data[s].update(src._data[s])
        self._source.update(src._source)
    def get(self, section, item, default=None):
        return self._data.get(section, {}).get(item, default)

    def backup(self, section, item):
        """return a tuple allowing restore to reinstall a previous value

        The main reason we need it is because it handles the "no data" case.
        """
        try:
            value = self._data[section][item]
            source = self.source(section, item)
            return (section, item, value, source)
        except KeyError:
            return (section, item)

    def source(self, section, item):
        return self._source.get((section, item), "")
    def sections(self):
        return sorted(self._data.keys())
    def items(self, section):
        return list(self._data.get(section, {}).iteritems())
    def set(self, section, item, value, source=""):
        if pycompat.ispy3:
            assert not isinstance(value, str), (
                'config values may not be unicode strings on Python 3')
        if section not in self:
            self._data[section] = util.cowsortdict()
        else:
            self._data[section] = self._data[section].preparewrite()
        self._data[section][item] = value
        if source:
            self._source = self._source.preparewrite()
            self._source[(section, item)] = source

    def restore(self, data):
        """restore data returned by self.backup"""
        self._source = self._source.preparewrite()
        if len(data) == 4:
            # restore old data
            section, item, value, source = data
            self._data[section] = self._data[section].preparewrite()
            self._data[section][item] = value
            self._source[(section, item)] = source
        else:
            # no data before, remove everything
            section, item = data
            if section in self._data:
                self._data[section].pop(item, None)
            self._source.pop((section, item), None)

    def parse(self, src, data, sections=None, remap=None, include=None):
        sectionre = util.re.compile(br'\[([^\[]+)\]')
        itemre = util.re.compile(br'([^=\s][^=]*?)\s*=\s*(.*\S|)')
        contre = util.re.compile(br'\s+(\S|\S.*\S)\s*$')
        emptyre = util.re.compile(br'(;|#|\s*$)')
        commentre = util.re.compile(br'(;|#)')
        unsetre = util.re.compile(br'%unset\s+(\S+)')
        includere = util.re.compile(br'%include\s+(\S|\S.*\S)\s*$')
        section = ""
        item = None
        line = 0
        cont = False

        if remap:
            section = remap.get(section, section)

        for l in data.splitlines(True):
            line += 1
            if line == 1 and l.startswith('\xef\xbb\xbf'):
                # Someone set us up the BOM
                l = l[3:]
            if cont:
                if commentre.match(l):
                    continue
                m = contre.match(l)
                if m:
                    if sections and section not in sections:
                        continue
                    v = self.get(section, item) + "\n" + m.group(1)
                    self.set(section, item, v, "%s:%d" % (src, line))
                    continue
                item = None
                cont = False
            m = includere.match(l)

            if m and include:
                expanded = util.expandpath(m.group(1))
                includepaths = [os.path.dirname(src)] + self._includepaths

                for base in includepaths:
                    inc = os.path.normpath(os.path.join(base, expanded))

                    try:
                        include(inc, remap=remap, sections=sections)
                        break
                    except IOError as inst:
                        if inst.errno != errno.ENOENT:
                            raise error.ParseError(_("cannot include %s (%s)")
                                                   % (inc, inst.strerror),
                                                   "%s:%d" % (src, line))
                continue
            if emptyre.match(l):
                continue
            m = sectionre.match(l)
            if m:
                section = m.group(1)
                if remap:
                    section = remap.get(section, section)
                if section not in self:
                    self._data[section] = util.cowsortdict()
                continue
            m = itemre.match(l)
            if m:
                item = m.group(1)
                cont = True
                if sections and section not in sections:
                    continue
                self.set(section, item, m.group(2), "%s:%d" % (src, line))
                continue
            m = unsetre.match(l)
            if m:
                name = m.group(1)
                if sections and section not in sections:
                    continue
                if self.get(section, name) is not None:
                    self._data[section] = self._data[section].preparewrite()
                    del self._data[section][name]
                self._unset.append((section, name))
                continue

            raise error.ParseError(l.rstrip(), ("%s:%d" % (src, line)))

    def read(self, path, fp=None, sections=None, remap=None):
        if not fp:
            fp = util.posixfile(path, 'rb')
        assert getattr(fp, 'mode', r'rb') == r'rb', (
            'config files must be opened in binary mode, got fp=%r mode=%r' % (
                fp, fp.mode))
        self.parse(path, fp.read(),
                   sections=sections, remap=remap, include=self.read)

def parselist(value):
    """parse a configuration value as a list of comma/space separated strings

    >>> parselist(b'this,is "a small" ,test')
    ['this', 'is', 'a small', 'test']
    """

    def _parse_plain(parts, s, offset):
        whitespace = False
        while offset < len(s) and (s[offset:offset + 1].isspace()
                                   or s[offset:offset + 1] == ','):
            whitespace = True
            offset += 1
        if offset >= len(s):
            return None, parts, offset
        if whitespace:
            parts.append('')
        if s[offset:offset + 1] == '"' and not parts[-1]:
            return _parse_quote, parts, offset + 1
        elif s[offset:offset + 1] == '"' and parts[-1][-1:] == '\\':
            parts[-1] = parts[-1][:-1] + s[offset:offset + 1]
            return _parse_plain, parts, offset + 1
        parts[-1] += s[offset:offset + 1]
        return _parse_plain, parts, offset + 1

    def _parse_quote(parts, s, offset):
        if offset < len(s) and s[offset:offset + 1] == '"': # ""
            parts.append('')
            offset += 1
            while offset < len(s) and (s[offset:offset + 1].isspace() or
                    s[offset:offset + 1] == ','):
                offset += 1
            return _parse_plain, parts, offset

        while offset < len(s) and s[offset:offset + 1] != '"':
            if (s[offset:offset + 1] == '\\' and offset + 1 < len(s)
                    and s[offset + 1:offset + 2] == '"'):
                offset += 1
                parts[-1] += '"'
            else:
                parts[-1] += s[offset:offset + 1]
            offset += 1

        if offset >= len(s):
            real_parts = _configlist(parts[-1])
            if not real_parts:
                parts[-1] = '"'
            else:
                real_parts[0] = '"' + real_parts[0]
                parts = parts[:-1]
                parts.extend(real_parts)
            return None, parts, offset

        offset += 1
        while offset < len(s) and s[offset:offset + 1] in [' ', ',']:
            offset += 1

        if offset < len(s):
            if offset + 1 == len(s) and s[offset:offset + 1] == '"':
                parts[-1] += '"'
                offset += 1
            else:
                parts.append('')
        else:
            return None, parts, offset

        return _parse_plain, parts, offset

    def _configlist(s):
        s = s.rstrip(' ,')
        if not s:
            return []
        parser, parts, offset = _parse_plain, [''], 0
        while parser:
            parser, parts, offset = parser(parts, s, offset)
        return parts

    if value is not None and isinstance(value, bytes):
        result = _configlist(value.lstrip(' ,\n'))
    else:
        result = value
    return result or []