view mercurial/revsetlang.py @ 48687:f8f2ecdde4b5

branchmap: skip obsolete revisions while computing heads

It's time to make this part of core Mercurial obsolescence-aware.

Not considering obsolete revisions when computing heads is clearly what
Mercurial should do. But there are a couple of small issues:

- Let's say tip of the repo is obsolete. There are two ways of finding tiprev
  for branchcache (both are in use): looking at input data for update() and
  looking at computed heads after update(). Previously, repo tip would be
  tiprev of the branchcache. With this patch, an obsolete revision can no
  longer be tiprev. And depending on what way we use for finding tiprev (input
  data vs computed heads) we'll get a different result. This is relevant when
  recomputing cache key from cache contents, and may lead to updating cache for
  obsolete revisions multiple times (not from scratch, because it still would
  be considered valid for a subset of revisions in the repo).

- If all commits on a branch are obsolete, the branchcache will include that
  branch, but the list of heads will be empty (that's why there's now `if not
  heads` when recomputing tiprev/tipnode from cache contents). Having an entry
  for every branch is currently required for notify extension (and
  test-notify.t to pass), because notify doesn't handle revsets in its
  subscription config very well and will throw an error if e.g. a branch
  doesn't exist.

- Cloning static HTTP repos may try to stat() a non-existent obsstore file. The
  issue is that we now care about obsolescence during clone, but statichttpvfs
  doesn't implement a stat method, so a regular vfs.stat() is used, and it
  assumes that file is local and calls os.stat().  During a clone, we're trying
  to stat() .hg/store/obsstore, but in static HTTP case we provide a literal
  URL to the obsstore file on the remote as if it were a local file path. On
  windows it actually results in a failure in test-static-http.t.

The first issue is going to be addressed in a series dedicated to making sure
branchcache is properly and timely written on disk (it wasn't perfect even
before this patch, but there aren't enough tests to demonstrate that). The
second issue will be addressed in a future patch for notify extension that will
make it not raise an exception if a branch doesn't exist. And the third one was
partially addressed in the previous patch in this series and will be properly
fixed in a future patch when this series is accepted.

filteredhash() grows a keyword argument to make sure that branchcache is also
invalidated when there are new obsolete revisions in its repo view. This way
the on-disk cache format is unchanged and compatible between versions (although
it will obviously be recomputed when switching versions before/after this patch
and the repo has obsolete revisions).

There's one test that uses plain `hg up` without arguments while updated to a
pruned commit. To make this test pass, simply return current working directory
parent. Later in this series this code will be replaced by what prune command
does: updating to the closest non-obsolete ancestor.

Test changes:

test-branch-change.t: update branch head and cache update message. The head of
default listed in hg heads is changed because revision 2 was rewritten as 7,
and 1 is the closest ancestor on the same branch, so it's the head of default
now.

The cache invalidation message appears now because of the cache hash change,
since we're now accounting for obsolete revisions. Here's some context:

"served.hidden" repo filter means everything is visible (no filtered
revisions), so before this series branch2-served.hidden file would not contain
any cache hash, only revnum and node. Now it also has a hash when there are
obsolete changesets in the repo. The command that the message appears for is
changing branch of 5 and 6, which are now obsolete, so the cache hash changes.

In general, when cache is simply out-of-date, it can be updated using the old
version as a base. But if cache hash differs, then the cache for that
particular repo filter is recomputed (at least with the current
implementation). This is what happens here.

test-obsmarker-template.t: the pull reports 2 heads changed, but after that the
repo correctly sees only 1. The new message could be better, but it's still an
improvement over the previous one where hg pull suggested merging with an
obsolete revision.

test-obsolete.t: we can see these revisions in hg log --hidden, but they
shouldn't be considered heads even with --hidden.

test-rebase-obsolete{,2}.t: there were new heads created previously after
making new orphan changesets, but they weren't detected. Now we are properly
detecting and reporting them.

test-rebase-obsolete4.t: there's only one head now because the other head is
pruned and was falsely reported before.

test-static-http.t: add obsstore to the list of requested files. This file
doesn't exist on the remotes, but clients want it anyway (they get 404). This
is fine, because there are other nonexistent files that clients request, like
.hg/bookmarks or .hg/cache/tags2-served.

Differential Revision: https://phab.mercurial-scm.org/D12097

# revsetlang.py - parser, tokenizer and utility for revision set language
#
# 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 string

from .i18n import _
from .pycompat import getattr
from .node import hex
from . import (
    error,
    parser,
    pycompat,
    smartset,
    util,
)
from .utils import stringutil

elements = {
    # token-type: binding-strength, primary, prefix, infix, suffix
    b"(": (21, None, (b"group", 1, b")"), (b"func", 1, b")"), None),
    b"[": (21, None, None, (b"subscript", 1, b"]"), None),
    b"#": (21, None, None, (b"relation", 21), None),
    b"##": (20, None, None, (b"_concat", 20), None),
    b"~": (18, None, None, (b"ancestor", 18), None),
    b"^": (18, None, None, (b"parent", 18), b"parentpost"),
    b"-": (5, None, (b"negate", 19), (b"minus", 5), None),
    b"::": (
        17,
        b"dagrangeall",
        (b"dagrangepre", 17),
        (b"dagrange", 17),
        b"dagrangepost",
    ),
    b"..": (
        17,
        b"dagrangeall",
        (b"dagrangepre", 17),
        (b"dagrange", 17),
        b"dagrangepost",
    ),
    b":": (15, b"rangeall", (b"rangepre", 15), (b"range", 15), b"rangepost"),
    b"not": (10, None, (b"not", 10), None, None),
    b"!": (10, None, (b"not", 10), None, None),
    b"and": (5, None, None, (b"and", 5), None),
    b"&": (5, None, None, (b"and", 5), None),
    b"%": (5, None, None, (b"only", 5), b"onlypost"),
    b"or": (4, None, None, (b"or", 4), None),
    b"|": (4, None, None, (b"or", 4), None),
    b"+": (4, None, None, (b"or", 4), None),
    b"=": (3, None, None, (b"keyvalue", 3), None),
    b",": (2, None, None, (b"list", 2), None),
    b")": (0, None, None, None, None),
    b"]": (0, None, None, None, None),
    b"symbol": (0, b"symbol", None, None, None),
    b"string": (0, b"string", None, None, None),
    b"end": (0, None, None, None, None),
}

keywords = {b'and', b'or', b'not'}

symbols = {}

_quoteletters = {b'"', b"'"}
_simpleopletters = set(pycompat.iterbytestr(b"()[]#:=,-|&+!~^%"))

# default set of valid characters for the initial letter of symbols
_syminitletters = set(
    pycompat.iterbytestr(
        pycompat.sysbytes(string.ascii_letters)
        + pycompat.sysbytes(string.digits)
        + b'._@'
    )
) | set(map(pycompat.bytechr, pycompat.xrange(128, 256)))

# default set of valid characters for non-initial letters of symbols
_symletters = _syminitletters | set(pycompat.iterbytestr(b'-/'))


def tokenize(program, lookup=None, syminitletters=None, symletters=None):
    """
    Parse a revset statement into a stream of tokens

    ``syminitletters`` is the set of valid characters for the initial
    letter of symbols.

    By default, character ``c`` is recognized as valid for initial
    letter of symbols, if ``c.isalnum() or c in '._@' or ord(c) > 127``.

    ``symletters`` is the set of valid characters for non-initial
    letters of symbols.

    By default, character ``c`` is recognized as valid for non-initial
    letters of symbols, if ``c.isalnum() or c in '-._/@' or ord(c) > 127``.

    Check that @ is a valid unquoted token character (issue3686):
    >>> list(tokenize(b"@::"))
    [('symbol', '@', 0), ('::', None, 1), ('end', None, 3)]

    """
    if not isinstance(program, bytes):
        raise error.ProgrammingError(
            b'revset statement must be bytes, got %r' % program
        )
    program = pycompat.bytestr(program)
    if syminitletters is None:
        syminitletters = _syminitletters
    if symletters is None:
        symletters = _symletters

    if program and lookup:
        # attempt to parse old-style ranges first to deal with
        # things like old-tag which contain query metacharacters
        parts = program.split(b':', 1)
        if all(lookup(sym) for sym in parts if sym):
            if parts[0]:
                yield (b'symbol', parts[0], 0)
            if len(parts) > 1:
                s = len(parts[0])
                yield (b':', None, s)
                if parts[1]:
                    yield (b'symbol', parts[1], s + 1)
            yield (b'end', None, len(program))
            return

    pos, l = 0, len(program)
    while pos < l:
        c = program[pos]
        if c.isspace():  # skip inter-token whitespace
            pass
        elif (
            c == b':' and program[pos : pos + 2] == b'::'
        ):  # look ahead carefully
            yield (b'::', None, pos)
            pos += 1  # skip ahead
        elif (
            c == b'.' and program[pos : pos + 2] == b'..'
        ):  # look ahead carefully
            yield (b'..', None, pos)
            pos += 1  # skip ahead
        elif (
            c == b'#' and program[pos : pos + 2] == b'##'
        ):  # look ahead carefully
            yield (b'##', None, pos)
            pos += 1  # skip ahead
        elif c in _simpleopletters:  # handle simple operators
            yield (c, None, pos)
        elif (
            c in _quoteletters
            or c == b'r'
            and program[pos : pos + 2] in (b"r'", b'r"')
        ):  # handle quoted strings
            if c == b'r':
                pos += 1
                c = program[pos]
                decode = lambda x: x
            else:
                decode = parser.unescapestr
            pos += 1
            s = pos
            while pos < l:  # find closing quote
                d = program[pos]
                if d == b'\\':  # skip over escaped characters
                    pos += 2
                    continue
                if d == c:
                    yield (b'string', decode(program[s:pos]), s)
                    break
                pos += 1
            else:
                raise error.ParseError(_(b"unterminated string"), s)
        # gather up a symbol/keyword
        elif c in syminitletters:
            s = pos
            pos += 1
            while pos < l:  # find end of symbol
                d = program[pos]
                if d not in symletters:
                    break
                if (
                    d == b'.' and program[pos - 1] == b'.'
                ):  # special case for ..
                    pos -= 1
                    break
                pos += 1
            sym = program[s:pos]
            if sym in keywords:  # operator keywords
                yield (sym, None, s)
            elif b'-' in sym:
                # some jerk gave us foo-bar-baz, try to check if it's a symbol
                if lookup and lookup(sym):
                    # looks like a real symbol
                    yield (b'symbol', sym, s)
                else:
                    # looks like an expression
                    parts = sym.split(b'-')
                    for p in parts[:-1]:
                        if p:  # possible consecutive -
                            yield (b'symbol', p, s)
                        s += len(p)
                        yield (b'-', None, s)
                        s += 1
                    if parts[-1]:  # possible trailing -
                        yield (b'symbol', parts[-1], s)
            else:
                yield (b'symbol', sym, s)
            pos -= 1
        else:
            raise error.ParseError(
                _(b"syntax error in revset '%s'") % program, pos
            )
        pos += 1
    yield (b'end', None, pos)


# helpers

_notset = object()


def getsymbol(x):
    if x and x[0] == b'symbol':
        return x[1]
    raise error.ParseError(_(b'not a symbol'))


def getstring(x, err):
    if x and (x[0] == b'string' or x[0] == b'symbol'):
        return x[1]
    raise error.ParseError(err)


def getinteger(x, err, default=_notset):
    if not x and default is not _notset:
        return default
    try:
        return int(getstring(x, err))
    except ValueError:
        raise error.ParseError(err)


def getboolean(x, err):
    value = stringutil.parsebool(getsymbol(x))
    if value is not None:
        return value
    raise error.ParseError(err)


def getlist(x):
    if not x:
        return []
    if x[0] == b'list':
        return list(x[1:])
    return [x]


def getrange(x, err):
    if not x:
        raise error.ParseError(err)
    op = x[0]
    if op == b'range':
        return x[1], x[2]
    elif op == b'rangepre':
        return None, x[1]
    elif op == b'rangepost':
        return x[1], None
    elif op == b'rangeall':
        return None, None
    raise error.ParseError(err)


def getintrange(x, err1, err2, deffirst=_notset, deflast=_notset):
    """Get [first, last] integer range (both inclusive) from a parsed tree

    If any of the sides omitted, and if no default provided, ParseError will
    be raised.
    """
    if x and (x[0] == b'string' or x[0] == b'symbol'):
        n = getinteger(x, err1)
        return n, n
    a, b = getrange(x, err1)
    return getinteger(a, err2, deffirst), getinteger(b, err2, deflast)


def getargs(x, min, max, err):
    l = getlist(x)
    if len(l) < min or (max >= 0 and len(l) > max):
        raise error.ParseError(err)
    return l


def getargsdict(x, funcname, keys):
    return parser.buildargsdict(
        getlist(x),
        funcname,
        parser.splitargspec(keys),
        keyvaluenode=b'keyvalue',
        keynode=b'symbol',
    )


# cache of {spec: raw parsed tree} built internally
_treecache = {}


def _cachedtree(spec):
    # thread safe because parse() is reentrant and dict.__setitem__() is atomic
    tree = _treecache.get(spec)
    if tree is None:
        _treecache[spec] = tree = parse(spec)
    return tree


def _build(tmplspec, *repls):
    """Create raw parsed tree from a template revset statement

    >>> _build(b'f(_) and _', (b'string', b'1'), (b'symbol', b'2'))
    ('and', ('func', ('symbol', 'f'), ('string', '1')), ('symbol', '2'))
    """
    template = _cachedtree(tmplspec)
    return parser.buildtree(template, (b'symbol', b'_'), *repls)


def _match(patspec, tree):
    """Test if a tree matches the given pattern statement; return the matches

    >>> _match(b'f(_)', parse(b'f()'))
    >>> _match(b'f(_)', parse(b'f(1)'))
    [('func', ('symbol', 'f'), ('symbol', '1')), ('symbol', '1')]
    >>> _match(b'f(_)', parse(b'f(1, 2)'))
    """
    pattern = _cachedtree(patspec)
    return parser.matchtree(
        pattern, tree, (b'symbol', b'_'), {b'keyvalue', b'list'}
    )


def _matchonly(revs, bases):
    return _match(b'ancestors(_) and not ancestors(_)', (b'and', revs, bases))


def _fixops(x):
    """Rewrite raw parsed tree to resolve ambiguous syntax which cannot be
    handled well by our simple top-down parser"""
    if not isinstance(x, tuple):
        return x

    op = x[0]
    if op == b'parent':
        # x^:y means (x^) : y, not x ^ (:y)
        # x^:  means (x^) :,   not x ^ (:)
        post = (b'parentpost', x[1])
        if x[2][0] == b'dagrangepre':
            return _fixops((b'dagrange', post, x[2][1]))
        elif x[2][0] == b'dagrangeall':
            return _fixops((b'dagrangepost', post))
        elif x[2][0] == b'rangepre':
            return _fixops((b'range', post, x[2][1]))
        elif x[2][0] == b'rangeall':
            return _fixops((b'rangepost', post))
    elif op == b'or':
        # make number of arguments deterministic:
        # x + y + z -> (or x y z) -> (or (list x y z))
        return (op, _fixops((b'list',) + x[1:]))
    elif op == b'subscript' and x[1][0] == b'relation':
        # x#y[z] ternary
        return _fixops((b'relsubscript', x[1][1], x[1][2], x[2]))

    return (op,) + tuple(_fixops(y) for y in x[1:])


def _analyze(x):
    if x is None:
        return x

    op = x[0]
    if op == b'minus':
        return _analyze(_build(b'_ and not _', *x[1:]))
    elif op == b'only':
        return _analyze(_build(b'only(_, _)', *x[1:]))
    elif op == b'onlypost':
        return _analyze(_build(b'only(_)', x[1]))
    elif op == b'dagrangeall':
        raise error.ParseError(_(b"can't use '::' in this context"))
    elif op == b'dagrangepre':
        return _analyze(_build(b'ancestors(_)', x[1]))
    elif op == b'dagrangepost':
        return _analyze(_build(b'descendants(_)', x[1]))
    elif op == b'negate':
        s = getstring(x[1], _(b"can't negate that"))
        return _analyze((b'string', b'-' + s))
    elif op in (b'string', b'symbol', b'smartset'):
        return x
    elif op == b'rangeall':
        return (op, None)
    elif op in {b'or', b'not', b'rangepre', b'rangepost', b'parentpost'}:
        return (op, _analyze(x[1]))
    elif op == b'group':
        return _analyze(x[1])
    elif op in {
        b'and',
        b'dagrange',
        b'range',
        b'parent',
        b'ancestor',
        b'relation',
        b'subscript',
    }:
        ta = _analyze(x[1])
        tb = _analyze(x[2])
        return (op, ta, tb)
    elif op == b'relsubscript':
        ta = _analyze(x[1])
        tb = _analyze(x[2])
        tc = _analyze(x[3])
        return (op, ta, tb, tc)
    elif op == b'list':
        return (op,) + tuple(_analyze(y) for y in x[1:])
    elif op == b'keyvalue':
        return (op, x[1], _analyze(x[2]))
    elif op == b'func':
        return (op, x[1], _analyze(x[2]))
    raise ValueError(b'invalid operator %r' % op)


def analyze(x):
    """Transform raw parsed tree to evaluatable tree which can be fed to
    optimize() or getset()

    All pseudo operations should be mapped to real operations or functions
    defined in methods or symbols table respectively.
    """
    return _analyze(x)


def _optimize(x):
    if x is None:
        return 0, x

    op = x[0]
    if op in (b'string', b'symbol', b'smartset'):
        return 0.5, x  # single revisions are small
    elif op == b'and':
        wa, ta = _optimize(x[1])
        wb, tb = _optimize(x[2])
        w = min(wa, wb)

        # (draft/secret/_notpublic() & ::x) have a fast path
        m = _match(b'_() & ancestors(_)', (b'and', ta, tb))
        if m and getsymbol(m[1]) in {b'draft', b'secret', b'_notpublic'}:
            return w, _build(b'_phaseandancestors(_, _)', m[1], m[2])

        # (::x and not ::y)/(not ::y and ::x) have a fast path
        m = _matchonly(ta, tb) or _matchonly(tb, ta)
        if m:
            return w, _build(b'only(_, _)', *m[1:])

        m = _match(b'not _', tb)
        if m:
            return wa, (b'difference', ta, m[1])
        if wa > wb:
            op = b'andsmally'
        return w, (op, ta, tb)
    elif op == b'or':
        # fast path for machine-generated expression, that is likely to have
        # lots of trivial revisions: 'a + b + c()' to '_list(a b) + c()'
        ws, ts, ss = [], [], []

        def flushss():
            if not ss:
                return
            if len(ss) == 1:
                w, t = ss[0]
            else:
                s = b'\0'.join(t[1] for w, t in ss)
                y = _build(b'_list(_)', (b'string', s))
                w, t = _optimize(y)
            ws.append(w)
            ts.append(t)
            del ss[:]

        for y in getlist(x[1]):
            w, t = _optimize(y)
            if t is not None and (t[0] == b'string' or t[0] == b'symbol'):
                ss.append((w, t))
                continue
            flushss()
            ws.append(w)
            ts.append(t)
        flushss()
        if len(ts) == 1:
            return ws[0], ts[0]  # 'or' operation is fully optimized out
        return max(ws), (op, (b'list',) + tuple(ts))
    elif op == b'not':
        # Optimize not public() to _notpublic() because we have a fast version
        if _match(b'public()', x[1]):
            o = _optimize(_build(b'_notpublic()'))
            return o[0], o[1]
        else:
            o = _optimize(x[1])
            return o[0], (op, o[1])
    elif op == b'rangeall':
        return 1, x
    elif op in (b'rangepre', b'rangepost', b'parentpost'):
        o = _optimize(x[1])
        return o[0], (op, o[1])
    elif op in (b'dagrange', b'range'):
        wa, ta = _optimize(x[1])
        wb, tb = _optimize(x[2])
        return wa + wb, (op, ta, tb)
    elif op in (b'parent', b'ancestor', b'relation', b'subscript'):
        w, t = _optimize(x[1])
        return w, (op, t, x[2])
    elif op == b'relsubscript':
        w, t = _optimize(x[1])
        return w, (op, t, x[2], x[3])
    elif op == b'list':
        ws, ts = zip(*(_optimize(y) for y in x[1:]))
        return sum(ws), (op,) + ts
    elif op == b'keyvalue':
        w, t = _optimize(x[2])
        return w, (op, x[1], t)
    elif op == b'func':
        f = getsymbol(x[1])
        wa, ta = _optimize(x[2])
        w = getattr(symbols.get(f), '_weight', 1)
        m = _match(b'commonancestors(_)', ta)

        # Optimize heads(commonancestors(_)) because we have a fast version
        if f == b'heads' and m:
            return w + wa, _build(b'_commonancestorheads(_)', m[1])

        return w + wa, (op, x[1], ta)
    raise ValueError(b'invalid operator %r' % op)


def optimize(tree):
    """Optimize evaluatable tree

    All pseudo operations should be transformed beforehand.
    """
    _weight, newtree = _optimize(tree)
    return newtree


# the set of valid characters for the initial letter of symbols in
# alias declarations and definitions
_aliassyminitletters = _syminitletters | {b'$'}


def _parsewith(spec, lookup=None, syminitletters=None):
    """Generate a parse tree of given spec with given tokenizing options

    >>> _parsewith(b'foo($1)', syminitletters=_aliassyminitletters)
    ('func', ('symbol', 'foo'), ('symbol', '$1'))
    >>> from . import error
    >>> from . import pycompat
    >>> try:
    ...   _parsewith(b'$1')
    ... except error.ParseError as e:
    ...   pycompat.sysstr(e.message)
    ...   e.location
    "syntax error in revset '$1'"
    0
    >>> try:
    ...   _parsewith(b'foo bar')
    ... except error.ParseError as e:
    ...   pycompat.sysstr(e.message)
    ...   e.location
    'invalid token'
    4
    """
    if lookup and spec.startswith(b'revset(') and spec.endswith(b')'):
        lookup = None
    p = parser.parser(elements)
    tree, pos = p.parse(
        tokenize(spec, lookup=lookup, syminitletters=syminitletters)
    )
    if pos != len(spec):
        raise error.ParseError(_(b'invalid token'), pos)
    return _fixops(parser.simplifyinfixops(tree, (b'list', b'or')))


class _aliasrules(parser.basealiasrules):
    """Parsing and expansion rule set of revset aliases"""

    _section = _(b'revset alias')

    @staticmethod
    def _parse(spec):
        """Parse alias declaration/definition ``spec``

        This allows symbol names to use also ``$`` as an initial letter
        (for backward compatibility), and callers of this function should
        examine whether ``$`` is used also for unexpected symbols or not.
        """
        return _parsewith(spec, syminitletters=_aliassyminitletters)

    @staticmethod
    def _trygetfunc(tree):
        if tree[0] == b'func' and tree[1][0] == b'symbol':
            return tree[1][1], getlist(tree[2])


def expandaliases(tree, aliases, warn=None):
    """Expand aliases in a tree, aliases is a list of (name, value) tuples"""
    aliases = _aliasrules.buildmap(aliases)
    tree = _aliasrules.expand(aliases, tree)
    # warn about problematic (but not referred) aliases
    if warn is not None:
        for name, alias in sorted(pycompat.iteritems(aliases)):
            if alias.error and not alias.warned:
                warn(_(b'warning: %s\n') % (alias.error))
                alias.warned = True
    return tree


def foldconcat(tree):
    """Fold elements to be concatenated by `##`"""
    if not isinstance(tree, tuple) or tree[0] in (
        b'string',
        b'symbol',
        b'smartset',
    ):
        return tree
    if tree[0] == b'_concat':
        pending = [tree]
        l = []
        while pending:
            e = pending.pop()
            if e[0] == b'_concat':
                pending.extend(reversed(e[1:]))
            elif e[0] in (b'string', b'symbol'):
                l.append(e[1])
            else:
                msg = _(b"\"##\" can't concatenate \"%s\" element") % (e[0])
                raise error.ParseError(msg)
        return (b'string', b''.join(l))
    else:
        return tuple(foldconcat(t) for t in tree)


def parse(spec, lookup=None):
    try:
        return _parsewith(spec, lookup=lookup)
    except error.ParseError as inst:
        if inst.location is not None:
            loc = inst.location
            # Remove newlines -- spaces are equivalent whitespace.
            spec = spec.replace(b'\n', b' ')
            # We want the caret to point to the place in the template that
            # failed to parse, but in a hint we get a open paren at the
            # start. Therefore, we print "loc + 1" spaces (instead of "loc")
            # to line up the caret with the location of the error.
            inst.hint = spec + b'\n' + b' ' * (loc + 1) + b'^ ' + _(b'here')
        raise


def _quote(s):
    r"""Quote a value in order to make it safe for the revset engine.

    >>> _quote(b'asdf')
    "'asdf'"
    >>> _quote(b"asdf'\"")
    '\'asdf\\\'"\''
    >>> _quote(b'asdf\'')
    "'asdf\\''"
    >>> _quote(1)
    "'1'"
    """
    return b"'%s'" % stringutil.escapestr(pycompat.bytestr(s))


def _formatargtype(c, arg):
    if c == b'd':
        return b'_rev(%d)' % int(arg)
    elif c == b's':
        return _quote(arg)
    elif c == b'r':
        if not isinstance(arg, bytes):
            raise TypeError
        parse(arg)  # make sure syntax errors are confined
        return b'(%s)' % arg
    elif c == b'n':
        return _quote(hex(arg))
    elif c == b'b':
        try:
            return _quote(arg.branch())
        except AttributeError:
            raise TypeError
    raise error.ParseError(_(b'unexpected revspec format character %s') % c)


def _formatlistexp(s, t):
    l = len(s)
    if l == 0:
        return b"_list('')"
    elif l == 1:
        return _formatargtype(t, s[0])
    elif t == b'd':
        return _formatintlist(s)
    elif t == b's':
        return b"_list(%s)" % _quote(b"\0".join(s))
    elif t == b'n':
        return b"_hexlist('%s')" % b"\0".join(hex(a) for a in s)
    elif t == b'b':
        try:
            return b"_list('%s')" % b"\0".join(a.branch() for a in s)
        except AttributeError:
            raise TypeError

    m = l // 2
    return b'(%s or %s)' % (_formatlistexp(s[:m], t), _formatlistexp(s[m:], t))


def _formatintlist(data):
    try:
        l = len(data)
        if l == 0:
            return b"_list('')"
        elif l == 1:
            return _formatargtype(b'd', data[0])
        return b"_intlist('%s')" % b"\0".join(b'%d' % int(a) for a in data)
    except (TypeError, ValueError):
        raise error.ParseError(_(b'invalid argument for revspec'))


def _formatparamexp(args, t):
    return b', '.join(_formatargtype(t, a) for a in args)


_formatlistfuncs = {
    b'l': _formatlistexp,
    b'p': _formatparamexp,
}


def formatspec(expr, *args):
    """
    This is a convenience function for using revsets internally, and
    escapes arguments appropriately. Aliases are intentionally ignored
    so that intended expression behavior isn't accidentally subverted.

    Supported arguments:

    %r = revset expression, parenthesized
    %d = rev(int(arg)), no quoting
    %s = string(arg), escaped and single-quoted
    %b = arg.branch(), escaped and single-quoted
    %n = hex(arg), single-quoted
    %% = a literal '%'

    Prefixing the type with 'l' specifies a parenthesized list of that type,
    and 'p' specifies a list of function parameters of that type.

    >>> formatspec(b'%r:: and %lr', b'10 or 11', (b"this()", b"that()"))
    '(10 or 11):: and ((this()) or (that()))'
    >>> formatspec(b'%d:: and not %d::', 10, 20)
    '_rev(10):: and not _rev(20)::'
    >>> formatspec(b'%ld or %ld', [], [1])
    "_list('') or _rev(1)"
    >>> formatspec(b'keyword(%s)', b'foo\\xe9')
    "keyword('foo\\\\xe9')"
    >>> b = lambda: b'default'
    >>> b.branch = b
    >>> formatspec(b'branch(%b)', b)
    "branch('default')"
    >>> formatspec(b'root(%ls)', [b'a', b'b', b'c', b'd'])
    "root(_list('a\\\\x00b\\\\x00c\\\\x00d'))"
    >>> formatspec(b'sort(%r, %ps)', b':', [b'desc', b'user'])
    "sort((:), 'desc', 'user')"
    >>> formatspec(b'%ls', [b'a', b"'"])
    "_list('a\\\\x00\\\\'')"
    """
    parsed = _parseargs(expr, args)
    ret = []
    for t, arg in parsed:
        if t is None:
            ret.append(arg)
        elif t == b'baseset':
            if isinstance(arg, set):
                arg = sorted(arg)
            ret.append(_formatintlist(list(arg)))
        else:
            raise error.ProgrammingError(b"unknown revspec item type: %r" % t)
    return b''.join(ret)


def spectree(expr, *args):
    """similar to formatspec but return a parsed and optimized tree"""
    parsed = _parseargs(expr, args)
    ret = []
    inputs = []
    for t, arg in parsed:
        if t is None:
            ret.append(arg)
        elif t == b'baseset':
            newtree = (b'smartset', smartset.baseset(arg))
            inputs.append(newtree)
            ret.append(b"$")
        else:
            raise error.ProgrammingError(b"unknown revspec item type: %r" % t)
    expr = b''.join(ret)
    tree = _parsewith(expr, syminitletters=_aliassyminitletters)
    tree = parser.buildtree(tree, (b'symbol', b'$'), *inputs)
    tree = foldconcat(tree)
    tree = analyze(tree)
    tree = optimize(tree)
    return tree


def _parseargs(expr, args):
    """parse the expression and replace all inexpensive args

    return a list of tuple [(arg-type, arg-value)]

    Arg-type can be:
    * None:      a string ready to be concatenated into a final spec
    * 'baseset': an iterable of revisions
    """
    expr = pycompat.bytestr(expr)
    argiter = iter(args)
    ret = []
    pos = 0
    while pos < len(expr):
        q = expr.find(b'%', pos)
        if q < 0:
            ret.append((None, expr[pos:]))
            break
        ret.append((None, expr[pos:q]))
        pos = q + 1
        try:
            d = expr[pos]
        except IndexError:
            raise error.ParseError(_(b'incomplete revspec format character'))
        if d == b'%':
            ret.append((None, d))
            pos += 1
            continue

        try:
            arg = next(argiter)
        except StopIteration:
            raise error.ParseError(_(b'missing argument for revspec'))
        f = _formatlistfuncs.get(d)
        if f:
            # a list of some type, might be expensive, do not replace
            pos += 1
            islist = d == b'l'
            try:
                d = expr[pos]
            except IndexError:
                raise error.ParseError(
                    _(b'incomplete revspec format character')
                )
            if islist and d == b'd' and arg:
                # we don't create a baseset yet, because it come with an
                # extra cost. If we are going to serialize it we better
                # skip it.
                ret.append((b'baseset', arg))
                pos += 1
                continue
            try:
                ret.append((None, f(list(arg), d)))
            except (TypeError, ValueError):
                raise error.ParseError(_(b'invalid argument for revspec'))
        else:
            # a single entry, not expensive, replace
            try:
                ret.append((None, _formatargtype(d, arg)))
            except (TypeError, ValueError):
                raise error.ParseError(_(b'invalid argument for revspec'))
        pos += 1

    try:
        next(argiter)
        raise error.ParseError(_(b'too many revspec arguments specified'))
    except StopIteration:
        pass
    return ret


def prettyformat(tree):
    return parser.prettyformat(tree, (b'string', b'symbol'))


def depth(tree):
    if isinstance(tree, tuple):
        return max(map(depth, tree)) + 1
    else:
        return 0


def funcsused(tree):
    if not isinstance(tree, tuple) or tree[0] in (b'string', b'symbol'):
        return set()
    else:
        funcs = set()
        for s in tree[1:]:
            funcs |= funcsused(s)
        if tree[0] == b'func':
            funcs.add(tree[1][1])
        return funcs


_hashre = util.re.compile(b'[0-9a-fA-F]{1,40}$')


def _ishashlikesymbol(symbol):
    """returns true if the symbol looks like a hash"""
    return _hashre.match(symbol)


def gethashlikesymbols(tree):
    """returns the list of symbols of the tree that look like hashes

    >>> gethashlikesymbols(parse(b'3::abe3ff'))
    ['3', 'abe3ff']
    >>> gethashlikesymbols(parse(b'precursors(.)'))
    []
    >>> gethashlikesymbols(parse(b'precursors(34)'))
    ['34']
    >>> gethashlikesymbols(parse(b'abe3ffZ'))
    []
    """
    if not tree:
        return []

    if tree[0] == b"symbol":
        if _ishashlikesymbol(tree[1]):
            return [tree[1]]
    elif len(tree) >= 3:
        results = []
        for subtree in tree[1:]:
            results += gethashlikesymbols(subtree)
        return results
    return []