revlog: remove some knowledge of sentinel nullid in index
I think the "-2" to mean "last position in index, not counting the
null revision at the end" is an implementation detail of the index
that we should avoid spreading knowledge of. I hope we can even remove
support for index[-2].
Differential Revision: https://phab.mercurial-scm.org/D4016
# filesetlang.py - parser, tokenizer and utility for file set language
#
# Copyright 2010 Matt Mackall <mpm@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 __future__ import absolute_import
from .i18n import _
from . import (
error,
parser,
pycompat,
)
elements = {
# token-type: binding-strength, primary, prefix, infix, suffix
"(": (20, None, ("group", 1, ")"), ("func", 1, ")"), None),
":": (15, None, None, ("kindpat", 15), None),
"-": (5, None, ("negate", 19), ("minus", 5), None),
"not": (10, None, ("not", 10), None, None),
"!": (10, None, ("not", 10), None, None),
"and": (5, None, None, ("and", 5), None),
"&": (5, None, None, ("and", 5), None),
"or": (4, None, None, ("or", 4), None),
"|": (4, None, None, ("or", 4), None),
"+": (4, None, None, ("or", 4), None),
",": (2, None, None, ("list", 2), None),
")": (0, None, None, None, None),
"symbol": (0, "symbol", None, None, None),
"string": (0, "string", None, None, None),
"end": (0, None, None, None, None),
}
keywords = {'and', 'or', 'not'}
symbols = {}
globchars = ".*{}[]?/\\_"
def tokenize(program):
pos, l = 0, len(program)
program = pycompat.bytestr(program)
while pos < l:
c = program[pos]
if c.isspace(): # skip inter-token whitespace
pass
elif c in "(),-:|&+!": # handle simple operators
yield (c, None, pos)
elif (c in '"\'' or c == 'r' and
program[pos:pos + 2] in ("r'", 'r"')): # handle quoted strings
if c == '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 == '\\': # skip over escaped characters
pos += 2
continue
if d == c:
yield ('string', decode(program[s:pos]), s)
break
pos += 1
else:
raise error.ParseError(_("unterminated string"), s)
elif c.isalnum() or c in globchars or ord(c) > 127:
# gather up a symbol/keyword
s = pos
pos += 1
while pos < l: # find end of symbol
d = program[pos]
if not (d.isalnum() or d in globchars or ord(d) > 127):
break
pos += 1
sym = program[s:pos]
if sym in keywords: # operator keywords
yield (sym, None, s)
else:
yield ('symbol', sym, s)
pos -= 1
else:
raise error.ParseError(_("syntax error"), pos)
pos += 1
yield ('end', None, pos)
def parse(expr):
p = parser.parser(elements)
tree, pos = p.parse(tokenize(expr))
if pos != len(expr):
raise error.ParseError(_("invalid token"), pos)
return parser.simplifyinfixops(tree, {'list', 'or'})
def getsymbol(x):
if x and x[0] == 'symbol':
return x[1]
raise error.ParseError(_('not a symbol'))
def getstring(x, err):
if x and (x[0] == 'string' or x[0] == 'symbol'):
return x[1]
raise error.ParseError(err)
def getkindpat(x, y, allkinds, err):
kind = getsymbol(x)
pat = getstring(y, err)
if kind not in allkinds:
raise error.ParseError(_("invalid pattern kind: %s") % kind)
return '%s:%s' % (kind, pat)
def getpattern(x, allkinds, err):
if x and x[0] == 'kindpat':
return getkindpat(x[1], x[2], allkinds, err)
return getstring(x, err)
def getlist(x):
if not x:
return []
if x[0] == 'list':
return list(x[1:])
return [x]
def getargs(x, min, max, err):
l = getlist(x)
if len(l) < min or len(l) > max:
raise error.ParseError(err)
return l
def _analyze(x):
if x is None:
return x
op = x[0]
if op in {'string', 'symbol'}:
return x
if op == 'kindpat':
getsymbol(x[1]) # kind must be a symbol
t = _analyze(x[2])
return (op, x[1], t)
if op == 'group':
return _analyze(x[1])
if op == 'negate':
raise error.ParseError(_("can't use negate operator in this context"))
if op == 'not':
t = _analyze(x[1])
return (op, t)
if op == 'and':
ta = _analyze(x[1])
tb = _analyze(x[2])
return (op, ta, tb)
if op == 'minus':
return _analyze(('and', x[1], ('not', x[2])))
if op in {'list', 'or'}:
ts = tuple(_analyze(y) for y in x[1:])
return (op,) + ts
if op == 'func':
getsymbol(x[1]) # function name must be a symbol
ta = _analyze(x[2])
return (op, x[1], ta)
raise error.ProgrammingError('invalid operator %r' % op)
def analyze(x):
"""Transform raw parsed tree to evaluatable tree which can be fed to
optimize() or getmatch()
All pseudo operations should be mapped to real operations or functions
defined in methods or symbols table respectively.
"""
return _analyze(x)
def _optimizeandops(op, ta, tb):
if tb is not None and tb[0] == 'not':
return ('minus', ta, tb[1])
return (op, ta, tb)
def _optimize(x):
if x is None:
return 0, x
op = x[0]
if op in {'string', 'symbol'}:
return 0.5, x
if op == 'kindpat':
w, t = _optimize(x[2])
return w, (op, x[1], t)
if op == 'not':
w, t = _optimize(x[1])
return w, (op, t)
if op == 'and':
wa, ta = _optimize(x[1])
wb, tb = _optimize(x[2])
if wa <= wb:
return wa, _optimizeandops(op, ta, tb)
else:
return wb, _optimizeandops(op, tb, ta)
if op == 'or':
ws, ts = zip(*(_optimize(y) for y in x[1:]))
return max(ws), (op,) + ts
if op == 'list':
ws, ts = zip(*(_optimize(y) for y in x[1:]))
return sum(ws), (op,) + ts
if op == 'func':
f = getsymbol(x[1])
w = getattr(symbols.get(f), '_weight', 1)
wa, ta = _optimize(x[2])
return w + wa, (op, x[1], ta)
raise error.ProgrammingError('invalid operator %r' % op)
def optimize(x):
"""Reorder/rewrite evaluatable tree for optimization
All pseudo operations should be transformed beforehand.
"""
_w, t = _optimize(x)
return t
def prettyformat(tree):
return parser.prettyformat(tree, ('string', 'symbol'))