view mercurial/fileset.py @ 49000:dd6b67d5c256 stable

rust: fix unsound `OwningDirstateMap`

As per the previous patch, `OwningDirstateMap` is unsound. Self-referential
structs are difficult to implement correctly in Rust since the compiler is
free to move structs around as much as it wants to. They are also very rarely
needed in practice, so the state-of-the-art on how they should be done within
the Rust rules is still a bit new.

The crate `ouroboros` is an attempt at providing a safe way (in the Rust sense)
of declaring self-referential structs. It is getting a lot attention and was
improved very quickly when soundness issues were found in the past: rather than
relying on our own (limited) review circle, we might as well use the de-facto
common crate to fix this problem. This will give us a much better chance of
finding issues should any new ones be discovered as well as the benefit of
fewer `unsafe` APIs of our own.

I was starting to think about how I would present a safe API to the old struct
but soon realized that the callback-based approach was already done in
`ouroboros`, along with a lot more care towards refusing incorrect structs.

In short: we don't return a mutable reference to the `DirstateMap` anymore, we
expect users of its API to pass a `FnOnce` that takes the map as an argument.
This allows our `OwningDirstateMap` to control the input and output lifetimes
of the code that modifies it to prevent such issues.

Changing to `ouroboros` meant changing every API with it, but it is relatively
low churn in the end. It correctly identified the example buggy modification of
`copy_map_insert` outlined in the previous patch as violating the borrow rules.

Differential Revision: https://phab.mercurial-scm.org/D12429

# fileset.py - file set queries for mercurial
#
# Copyright 2010 Olivia Mackall <[e-mail]>
#
# 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 re

from .i18n import _
from .pycompat import getattr
from . import (
    error,
    filesetlang,
    match as matchmod,
    mergestate as mergestatemod,
    pycompat,
    registrar,
    scmutil,
    util,
)
from .utils import stringutil

# common weight constants
_WEIGHT_CHECK_FILENAME = filesetlang.WEIGHT_CHECK_FILENAME
_WEIGHT_READ_CONTENTS = filesetlang.WEIGHT_READ_CONTENTS
_WEIGHT_STATUS = filesetlang.WEIGHT_STATUS
_WEIGHT_STATUS_THOROUGH = filesetlang.WEIGHT_STATUS_THOROUGH

# helpers for processing parsed tree
getsymbol = filesetlang.getsymbol
getstring = filesetlang.getstring
_getkindpat = filesetlang.getkindpat
getpattern = filesetlang.getpattern
getargs = filesetlang.getargs


def getmatch(mctx, x):
    if not x:
        raise error.ParseError(_(b"missing argument"))
    return methods[x[0]](mctx, *x[1:])


def getmatchwithstatus(mctx, x, hint):
    keys = set(getstring(hint, b'status hint must be a string').split())
    return getmatch(mctx.withstatus(keys), x)


def stringmatch(mctx, x):
    return mctx.matcher([x])


def kindpatmatch(mctx, x, y):
    return stringmatch(
        mctx,
        _getkindpat(
            x, y, matchmod.allpatternkinds, _(b"pattern must be a string")
        ),
    )


def patternsmatch(mctx, *xs):
    allkinds = matchmod.allpatternkinds
    patterns = [
        getpattern(x, allkinds, _(b"pattern must be a string")) for x in xs
    ]
    return mctx.matcher(patterns)


def andmatch(mctx, x, y):
    xm = getmatch(mctx, x)
    ym = getmatch(mctx.narrowed(xm), y)
    return matchmod.intersectmatchers(xm, ym)


def ormatch(mctx, *xs):
    ms = [getmatch(mctx, x) for x in xs]
    return matchmod.unionmatcher(ms)


def notmatch(mctx, x):
    m = getmatch(mctx, x)
    return mctx.predicate(lambda f: not m(f), predrepr=(b'<not %r>', m))


def minusmatch(mctx, x, y):
    xm = getmatch(mctx, x)
    ym = getmatch(mctx.narrowed(xm), y)
    return matchmod.differencematcher(xm, ym)


def listmatch(mctx, *xs):
    raise error.ParseError(
        _(b"can't use a list in this context"),
        hint=_(b'see \'hg help "filesets.x or y"\''),
    )


def func(mctx, a, b):
    funcname = getsymbol(a)
    if funcname in symbols:
        return symbols[funcname](mctx, b)

    keep = lambda fn: getattr(fn, '__doc__', None) is not None

    syms = [s for (s, fn) in symbols.items() if keep(fn)]
    raise error.UnknownIdentifier(funcname, syms)


# symbols are callable like:
#  fun(mctx, x)
# with:
#  mctx - current matchctx instance
#  x - argument in tree form
symbols = filesetlang.symbols

predicate = registrar.filesetpredicate(symbols)


@predicate(b'modified()', callstatus=True, weight=_WEIGHT_STATUS)
def modified(mctx, x):
    """File that is modified according to :hg:`status`."""
    # i18n: "modified" is a keyword
    getargs(x, 0, 0, _(b"modified takes no arguments"))
    s = set(mctx.status().modified)
    return mctx.predicate(s.__contains__, predrepr=b'modified')


@predicate(b'added()', callstatus=True, weight=_WEIGHT_STATUS)
def added(mctx, x):
    """File that is added according to :hg:`status`."""
    # i18n: "added" is a keyword
    getargs(x, 0, 0, _(b"added takes no arguments"))
    s = set(mctx.status().added)
    return mctx.predicate(s.__contains__, predrepr=b'added')


@predicate(b'removed()', callstatus=True, weight=_WEIGHT_STATUS)
def removed(mctx, x):
    """File that is removed according to :hg:`status`."""
    # i18n: "removed" is a keyword
    getargs(x, 0, 0, _(b"removed takes no arguments"))
    s = set(mctx.status().removed)
    return mctx.predicate(s.__contains__, predrepr=b'removed')


@predicate(b'deleted()', callstatus=True, weight=_WEIGHT_STATUS)
def deleted(mctx, x):
    """Alias for ``missing()``."""
    # i18n: "deleted" is a keyword
    getargs(x, 0, 0, _(b"deleted takes no arguments"))
    s = set(mctx.status().deleted)
    return mctx.predicate(s.__contains__, predrepr=b'deleted')


@predicate(b'missing()', callstatus=True, weight=_WEIGHT_STATUS)
def missing(mctx, x):
    """File that is missing according to :hg:`status`."""
    # i18n: "missing" is a keyword
    getargs(x, 0, 0, _(b"missing takes no arguments"))
    s = set(mctx.status().deleted)
    return mctx.predicate(s.__contains__, predrepr=b'deleted')


@predicate(b'unknown()', callstatus=True, weight=_WEIGHT_STATUS_THOROUGH)
def unknown(mctx, x):
    """File that is unknown according to :hg:`status`."""
    # i18n: "unknown" is a keyword
    getargs(x, 0, 0, _(b"unknown takes no arguments"))
    s = set(mctx.status().unknown)
    return mctx.predicate(s.__contains__, predrepr=b'unknown')


@predicate(b'ignored()', callstatus=True, weight=_WEIGHT_STATUS_THOROUGH)
def ignored(mctx, x):
    """File that is ignored according to :hg:`status`."""
    # i18n: "ignored" is a keyword
    getargs(x, 0, 0, _(b"ignored takes no arguments"))
    s = set(mctx.status().ignored)
    return mctx.predicate(s.__contains__, predrepr=b'ignored')


@predicate(b'clean()', callstatus=True, weight=_WEIGHT_STATUS)
def clean(mctx, x):
    """File that is clean according to :hg:`status`."""
    # i18n: "clean" is a keyword
    getargs(x, 0, 0, _(b"clean takes no arguments"))
    s = set(mctx.status().clean)
    return mctx.predicate(s.__contains__, predrepr=b'clean')


@predicate(b'tracked()')
def tracked(mctx, x):
    """File that is under Mercurial control."""
    # i18n: "tracked" is a keyword
    getargs(x, 0, 0, _(b"tracked takes no arguments"))
    return mctx.predicate(mctx.ctx.__contains__, predrepr=b'tracked')


@predicate(b'binary()', weight=_WEIGHT_READ_CONTENTS)
def binary(mctx, x):
    """File that appears to be binary (contains NUL bytes)."""
    # i18n: "binary" is a keyword
    getargs(x, 0, 0, _(b"binary takes no arguments"))
    return mctx.fpredicate(
        lambda fctx: fctx.isbinary(), predrepr=b'binary', cache=True
    )


@predicate(b'exec()')
def exec_(mctx, x):
    """File that is marked as executable."""
    # i18n: "exec" is a keyword
    getargs(x, 0, 0, _(b"exec takes no arguments"))
    ctx = mctx.ctx
    return mctx.predicate(lambda f: ctx.flags(f) == b'x', predrepr=b'exec')


@predicate(b'symlink()')
def symlink(mctx, x):
    """File that is marked as a symlink."""
    # i18n: "symlink" is a keyword
    getargs(x, 0, 0, _(b"symlink takes no arguments"))
    ctx = mctx.ctx
    return mctx.predicate(lambda f: ctx.flags(f) == b'l', predrepr=b'symlink')


@predicate(b'resolved()', weight=_WEIGHT_STATUS)
def resolved(mctx, x):
    """File that is marked resolved according to :hg:`resolve -l`."""
    # i18n: "resolved" is a keyword
    getargs(x, 0, 0, _(b"resolved takes no arguments"))
    if mctx.ctx.rev() is not None:
        return mctx.never()
    ms = mergestatemod.mergestate.read(mctx.ctx.repo())
    return mctx.predicate(
        lambda f: f in ms and ms[f] == b'r', predrepr=b'resolved'
    )


@predicate(b'unresolved()', weight=_WEIGHT_STATUS)
def unresolved(mctx, x):
    """File that is marked unresolved according to :hg:`resolve -l`."""
    # i18n: "unresolved" is a keyword
    getargs(x, 0, 0, _(b"unresolved takes no arguments"))
    if mctx.ctx.rev() is not None:
        return mctx.never()
    ms = mergestatemod.mergestate.read(mctx.ctx.repo())
    return mctx.predicate(
        lambda f: f in ms and ms[f] == b'u', predrepr=b'unresolved'
    )


@predicate(b'hgignore()', weight=_WEIGHT_STATUS)
def hgignore(mctx, x):
    """File that matches the active .hgignore pattern."""
    # i18n: "hgignore" is a keyword
    getargs(x, 0, 0, _(b"hgignore takes no arguments"))
    return mctx.ctx.repo().dirstate._ignore


@predicate(b'portable()', weight=_WEIGHT_CHECK_FILENAME)
def portable(mctx, x):
    """File that has a portable name. (This doesn't include filenames with case
    collisions.)
    """
    # i18n: "portable" is a keyword
    getargs(x, 0, 0, _(b"portable takes no arguments"))
    return mctx.predicate(
        lambda f: util.checkwinfilename(f) is None, predrepr=b'portable'
    )


@predicate(b'grep(regex)', weight=_WEIGHT_READ_CONTENTS)
def grep(mctx, x):
    """File contains the given regular expression."""
    try:
        # i18n: "grep" is a keyword
        r = re.compile(getstring(x, _(b"grep requires a pattern")))
    except re.error as e:
        raise error.ParseError(
            _(b'invalid match pattern: %s') % stringutil.forcebytestr(e)
        )
    return mctx.fpredicate(
        lambda fctx: r.search(fctx.data()),
        predrepr=(b'grep(%r)', r.pattern),
        cache=True,
    )


def _sizetomax(s):
    try:
        s = s.strip().lower()
        for k, v in util._sizeunits:
            if s.endswith(k):
                # max(4k) = 5k - 1, max(4.5k) = 4.6k - 1
                n = s[: -len(k)]
                inc = 1.0
                if b"." in n:
                    inc /= 10 ** len(n.split(b".")[1])
                return int((float(n) + inc) * v) - 1
        # no extension, this is a precise value
        return int(s)
    except ValueError:
        raise error.ParseError(_(b"couldn't parse size: %s") % s)


def sizematcher(expr):
    """Return a function(size) -> bool from the ``size()`` expression"""
    expr = expr.strip()
    if b'-' in expr:  # do we have a range?
        a, b = expr.split(b'-', 1)
        a = util.sizetoint(a)
        b = util.sizetoint(b)
        return lambda x: x >= a and x <= b
    elif expr.startswith(b"<="):
        a = util.sizetoint(expr[2:])
        return lambda x: x <= a
    elif expr.startswith(b"<"):
        a = util.sizetoint(expr[1:])
        return lambda x: x < a
    elif expr.startswith(b">="):
        a = util.sizetoint(expr[2:])
        return lambda x: x >= a
    elif expr.startswith(b">"):
        a = util.sizetoint(expr[1:])
        return lambda x: x > a
    else:
        a = util.sizetoint(expr)
        b = _sizetomax(expr)
        return lambda x: x >= a and x <= b


@predicate(b'size(expression)', weight=_WEIGHT_STATUS)
def size(mctx, x):
    """File size matches the given expression. Examples:

    - size('1k') - files from 1024 to 2047 bytes
    - size('< 20k') - files less than 20480 bytes
    - size('>= .5MB') - files at least 524288 bytes
    - size('4k - 1MB') - files from 4096 bytes to 1048576 bytes
    """
    # i18n: "size" is a keyword
    expr = getstring(x, _(b"size requires an expression"))
    m = sizematcher(expr)
    return mctx.fpredicate(
        lambda fctx: m(fctx.size()), predrepr=(b'size(%r)', expr), cache=True
    )


@predicate(b'encoding(name)', weight=_WEIGHT_READ_CONTENTS)
def encoding(mctx, x):
    """File can be successfully decoded with the given character
    encoding. May not be useful for encodings other than ASCII and
    UTF-8.
    """

    # i18n: "encoding" is a keyword
    enc = getstring(x, _(b"encoding requires an encoding name"))

    def encp(fctx):
        d = fctx.data()
        try:
            d.decode(pycompat.sysstr(enc))
            return True
        except LookupError:
            raise error.Abort(_(b"unknown encoding '%s'") % enc)
        except UnicodeDecodeError:
            return False

    return mctx.fpredicate(encp, predrepr=(b'encoding(%r)', enc), cache=True)


@predicate(b'eol(style)', weight=_WEIGHT_READ_CONTENTS)
def eol(mctx, x):
    """File contains newlines of the given style (dos, unix, mac). Binary
    files are excluded, files with mixed line endings match multiple
    styles.
    """

    # i18n: "eol" is a keyword
    enc = getstring(x, _(b"eol requires a style name"))

    def eolp(fctx):
        if fctx.isbinary():
            return False
        d = fctx.data()
        if (enc == b'dos' or enc == b'win') and b'\r\n' in d:
            return True
        elif enc == b'unix' and re.search(b'(?<!\r)\n', d):
            return True
        elif enc == b'mac' and re.search(b'\r(?!\n)', d):
            return True
        return False

    return mctx.fpredicate(eolp, predrepr=(b'eol(%r)', enc), cache=True)


@predicate(b'copied()')
def copied(mctx, x):
    """File that is recorded as being copied."""
    # i18n: "copied" is a keyword
    getargs(x, 0, 0, _(b"copied takes no arguments"))

    def copiedp(fctx):
        p = fctx.parents()
        return p and p[0].path() != fctx.path()

    return mctx.fpredicate(copiedp, predrepr=b'copied', cache=True)


@predicate(b'revs(revs, pattern)', weight=_WEIGHT_STATUS)
def revs(mctx, x):
    """Evaluate set in the specified revisions. If the revset match multiple
    revs, this will return file matching pattern in any of the revision.
    """
    # i18n: "revs" is a keyword
    r, x = getargs(x, 2, 2, _(b"revs takes two arguments"))
    # i18n: "revs" is a keyword
    revspec = getstring(r, _(b"first argument to revs must be a revision"))
    repo = mctx.ctx.repo()
    revs = scmutil.revrange(repo, [revspec])

    matchers = []
    for r in revs:
        ctx = repo[r]
        mc = mctx.switch(ctx.p1(), ctx)
        matchers.append(getmatch(mc, x))
    if not matchers:
        return mctx.never()
    if len(matchers) == 1:
        return matchers[0]
    return matchmod.unionmatcher(matchers)


@predicate(b'status(base, rev, pattern)', weight=_WEIGHT_STATUS)
def status(mctx, x):
    """Evaluate predicate using status change between ``base`` and
    ``rev``. Examples:

    - ``status(3, 7, added())`` - matches files added from "3" to "7"
    """
    repo = mctx.ctx.repo()
    # i18n: "status" is a keyword
    b, r, x = getargs(x, 3, 3, _(b"status takes three arguments"))
    # i18n: "status" is a keyword
    baseerr = _(b"first argument to status must be a revision")
    baserevspec = getstring(b, baseerr)
    if not baserevspec:
        raise error.ParseError(baseerr)
    reverr = _(b"second argument to status must be a revision")
    revspec = getstring(r, reverr)
    if not revspec:
        raise error.ParseError(reverr)
    basectx, ctx = scmutil.revpair(repo, [baserevspec, revspec])
    mc = mctx.switch(basectx, ctx)
    return getmatch(mc, x)


@predicate(b'subrepo([pattern])')
def subrepo(mctx, x):
    """Subrepositories whose paths match the given pattern."""
    # i18n: "subrepo" is a keyword
    getargs(x, 0, 1, _(b"subrepo takes at most one argument"))
    ctx = mctx.ctx
    sstate = ctx.substate
    if x:
        pat = getpattern(
            x,
            matchmod.allpatternkinds,
            # i18n: "subrepo" is a keyword
            _(b"subrepo requires a pattern or no arguments"),
        )
        fast = not matchmod.patkind(pat)
        if fast:

            def m(s):
                return s == pat

        else:
            m = matchmod.match(ctx.repo().root, b'', [pat], ctx=ctx)
        return mctx.predicate(
            lambda f: f in sstate and m(f), predrepr=(b'subrepo(%r)', pat)
        )
    else:
        return mctx.predicate(sstate.__contains__, predrepr=b'subrepo')


methods = {
    b'withstatus': getmatchwithstatus,
    b'string': stringmatch,
    b'symbol': stringmatch,
    b'kindpat': kindpatmatch,
    b'patterns': patternsmatch,
    b'and': andmatch,
    b'or': ormatch,
    b'minus': minusmatch,
    b'list': listmatch,
    b'not': notmatch,
    b'func': func,
}


class matchctx(object):
    def __init__(self, basectx, ctx, cwd, badfn=None):
        self._basectx = basectx
        self.ctx = ctx
        self._badfn = badfn
        self._match = None
        self._status = None
        self.cwd = cwd

    def narrowed(self, match):
        """Create matchctx for a sub-tree narrowed by the given matcher"""
        mctx = matchctx(self._basectx, self.ctx, self.cwd, self._badfn)
        mctx._match = match
        # leave wider status which we don't have to care
        mctx._status = self._status
        return mctx

    def switch(self, basectx, ctx):
        mctx = matchctx(basectx, ctx, self.cwd, self._badfn)
        mctx._match = self._match
        return mctx

    def withstatus(self, keys):
        """Create matchctx which has precomputed status specified by the keys"""
        mctx = matchctx(self._basectx, self.ctx, self.cwd, self._badfn)
        mctx._match = self._match
        mctx._buildstatus(keys)
        return mctx

    def _buildstatus(self, keys):
        self._status = self._basectx.status(
            self.ctx,
            self._match,
            listignored=b'ignored' in keys,
            listclean=b'clean' in keys,
            listunknown=b'unknown' in keys,
        )

    def status(self):
        return self._status

    def matcher(self, patterns):
        return self.ctx.match(patterns, badfn=self._badfn, cwd=self.cwd)

    def predicate(self, predfn, predrepr=None, cache=False):
        """Create a matcher to select files by predfn(filename)"""
        if cache:
            predfn = util.cachefunc(predfn)
        return matchmod.predicatematcher(
            predfn, predrepr=predrepr, badfn=self._badfn
        )

    def fpredicate(self, predfn, predrepr=None, cache=False):
        """Create a matcher to select files by predfn(fctx) at the current
        revision

        Missing files are ignored.
        """
        ctx = self.ctx
        if ctx.rev() is None:

            def fctxpredfn(f):
                try:
                    fctx = ctx[f]
                except error.LookupError:
                    return False
                try:
                    fctx.audit()
                except error.Abort:
                    return False
                try:
                    return predfn(fctx)
                except (IOError, OSError) as e:
                    # open()-ing a directory fails with EACCES on Windows
                    if e.errno in (
                        errno.ENOENT,
                        errno.EACCES,
                        errno.ENOTDIR,
                        errno.EISDIR,
                    ):
                        return False
                    raise

        else:

            def fctxpredfn(f):
                try:
                    fctx = ctx[f]
                except error.LookupError:
                    return False
                return predfn(fctx)

        return self.predicate(fctxpredfn, predrepr=predrepr, cache=cache)

    def never(self):
        """Create a matcher to select nothing"""
        return matchmod.never(badfn=self._badfn)


def match(ctx, cwd, expr, badfn=None):
    """Create a matcher for a single fileset expression"""
    tree = filesetlang.parse(expr)
    tree = filesetlang.analyze(tree)
    tree = filesetlang.optimize(tree)
    mctx = matchctx(ctx.p1(), ctx, cwd, badfn=badfn)
    return getmatch(mctx, tree)


def loadpredicate(ui, extname, registrarobj):
    """Load fileset predicates from specified registrarobj"""
    for name, func in pycompat.iteritems(registrarobj._table):
        symbols[name] = func


# tell hggettext to extract docstrings from these functions:
i18nfunctions = symbols.values()