stringutil: move _formatsetrepr() from smartset

I'll add a matcher subclass wrapping a boolean function, which will use
buildrepr() to provide debugging information in a similar way to
smartset.filteredset.

mercurial/smartset.py

@@ -1,1131 +1,1111 b''
 # smartset.py - data structure for revision set
 #
 # Copyright 2010 Matt 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
 
 from . import (
     encoding,
     error,
     pycompat,
     util,
 )
-
-def _formatsetrepr(r):
-    """Format an optional printable representation of a set
-
-    ========  =================================
-    type(r)   example
-    ========  =================================
-    tuple     ('<not %r>', other)
-    bytes     '<branch closed>'
-    callable  lambda: '<branch %r>' % sorted(b)
-    object    other
-    ========  =================================
-    """
-    if r is None:
-        return ''
-    elif isinstance(r, tuple):
-        return r[0] % pycompat.rapply(pycompat.maybebytestr, r[1:])
-    elif isinstance(r, bytes):
-        return r
-    elif callable(r):
-        return r()
-    else:
-        return pycompat.byterepr(r)
+from .utils import (
+    stringutil,
+)
 
 def _typename(o):
     return pycompat.sysbytes(type(o).__name__).lstrip('_')
 
 class abstractsmartset(object):
 
     def __nonzero__(self):
         """True if the smartset is not empty"""
         raise NotImplementedError()
 
     __bool__ = __nonzero__
 
     def __contains__(self, rev):
         """provide fast membership testing"""
         raise NotImplementedError()
 
     def __iter__(self):
         """iterate the set in the order it is supposed to be iterated"""
         raise NotImplementedError()
 
     # Attributes containing a function to perform a fast iteration in a given
     # direction. A smartset can have none, one, or both defined.
     #
     # Default value is None instead of a function returning None to avoid
     # initializing an iterator just for testing if a fast method exists.
     fastasc = None
     fastdesc = None
 
     def isascending(self):
         """True if the set will iterate in ascending order"""
         raise NotImplementedError()
 
     def isdescending(self):
         """True if the set will iterate in descending order"""
         raise NotImplementedError()
 
     def istopo(self):
         """True if the set will iterate in topographical order"""
         raise NotImplementedError()
 
     def min(self):
         """return the minimum element in the set"""
         if self.fastasc is None:
             v = min(self)
         else:
             for v in self.fastasc():
                 break
             else:
                 raise ValueError('arg is an empty sequence')
         self.min = lambda: v
         return v
 
     def max(self):
         """return the maximum element in the set"""
         if self.fastdesc is None:
             return max(self)
         else:
             for v in self.fastdesc():
                 break
             else:
                 raise ValueError('arg is an empty sequence')
         self.max = lambda: v
         return v
 
     def first(self):
         """return the first element in the set (user iteration perspective)
 
         Return None if the set is empty"""
         raise NotImplementedError()
 
     def last(self):
         """return the last element in the set (user iteration perspective)
 
         Return None if the set is empty"""
         raise NotImplementedError()
 
     def __len__(self):
         """return the length of the smartsets
 
         This can be expensive on smartset that could be lazy otherwise."""
         raise NotImplementedError()
 
     def reverse(self):
         """reverse the expected iteration order"""
         raise NotImplementedError()
 
     def sort(self, reverse=False):
         """get the set to iterate in an ascending or descending order"""
         raise NotImplementedError()
 
     def __and__(self, other):
         """Returns a new object with the intersection of the two collections.
 
         This is part of the mandatory API for smartset."""
         if isinstance(other, fullreposet):
             return self
         return self.filter(other.__contains__, condrepr=other, cache=False)
 
     def __add__(self, other):
         """Returns a new object with the union of the two collections.
 
         This is part of the mandatory API for smartset."""
         return addset(self, other)
 
     def __sub__(self, other):
         """Returns a new object with the substraction of the two collections.
 
         This is part of the mandatory API for smartset."""
         c = other.__contains__
         return self.filter(lambda r: not c(r), condrepr=('<not %r>', other),
                            cache=False)
 
     def filter(self, condition, condrepr=None, cache=True):
         """Returns this smartset filtered by condition as a new smartset.
 
         `condition` is a callable which takes a revision number and returns a
         boolean. Optional `condrepr` provides a printable representation of
         the given `condition`.
 
         This is part of the mandatory API for smartset."""
         # builtin cannot be cached. but do not needs to
         if cache and util.safehasattr(condition, 'func_code'):
             condition = util.cachefunc(condition)
         return filteredset(self, condition, condrepr)
 
     def slice(self, start, stop):
         """Return new smartset that contains selected elements from this set"""
         if start < 0 or stop < 0:
             raise error.ProgrammingError('negative index not allowed')
         return self._slice(start, stop)
 
     def _slice(self, start, stop):
         # sub classes may override this. start and stop must not be negative,
         # but start > stop is allowed, which should be an empty set.
         ys = []
         it = iter(self)
         for x in xrange(start):
             y = next(it, None)
             if y is None:
                 break
         for x in xrange(stop - start):
             y = next(it, None)
             if y is None:
                 break
             ys.append(y)
         return baseset(ys, datarepr=('slice=%d:%d %r', start, stop, self))
 
 class baseset(abstractsmartset):
     """Basic data structure that represents a revset and contains the basic
     operation that it should be able to perform.
 
     Every method in this class should be implemented by any smartset class.
 
     This class could be constructed by an (unordered) set, or an (ordered)
     list-like object. If a set is provided, it'll be sorted lazily.
 
     >>> x = [4, 0, 7, 6]
     >>> y = [5, 6, 7, 3]
 
     Construct by a set:
     >>> xs = baseset(set(x))
     >>> ys = baseset(set(y))
     >>> [list(i) for i in [xs + ys, xs & ys, xs - ys]]
     [[0, 4, 6, 7, 3, 5], [6, 7], [0, 4]]
     >>> [type(i).__name__ for i in [xs + ys, xs & ys, xs - ys]]
     ['addset', 'baseset', 'baseset']
 
     Construct by a list-like:
     >>> xs = baseset(x)
     >>> ys = baseset(i for i in y)
     >>> [list(i) for i in [xs + ys, xs & ys, xs - ys]]
     [[4, 0, 7, 6, 5, 3], [7, 6], [4, 0]]
     >>> [type(i).__name__ for i in [xs + ys, xs & ys, xs - ys]]
     ['addset', 'filteredset', 'filteredset']
 
     Populate "_set" fields in the lists so set optimization may be used:
     >>> [1 in xs, 3 in ys]
     [False, True]
 
     Without sort(), results won't be changed:
     >>> [list(i) for i in [xs + ys, xs & ys, xs - ys]]
     [[4, 0, 7, 6, 5, 3], [7, 6], [4, 0]]
     >>> [type(i).__name__ for i in [xs + ys, xs & ys, xs - ys]]
     ['addset', 'filteredset', 'filteredset']
 
     With sort(), set optimization could be used:
     >>> xs.sort(reverse=True)
     >>> [list(i) for i in [xs + ys, xs & ys, xs - ys]]
     [[7, 6, 4, 0, 5, 3], [7, 6], [4, 0]]
     >>> [type(i).__name__ for i in [xs + ys, xs & ys, xs - ys]]
     ['addset', 'baseset', 'baseset']
 
     >>> ys.sort()
     >>> [list(i) for i in [xs + ys, xs & ys, xs - ys]]
     [[7, 6, 4, 0, 3, 5], [7, 6], [4, 0]]
     >>> [type(i).__name__ for i in [xs + ys, xs & ys, xs - ys]]
     ['addset', 'baseset', 'baseset']
 
     istopo is preserved across set operations
     >>> xs = baseset(set(x), istopo=True)
     >>> rs = xs & ys
     >>> type(rs).__name__
     'baseset'
     >>> rs._istopo
     True
     """
     def __init__(self, data=(), datarepr=None, istopo=False):
         """
         datarepr: a tuple of (format, obj, ...), a function or an object that
                   provides a printable representation of the given data.
         """
         self._ascending = None
         self._istopo = istopo
         if isinstance(data, set):
             # converting set to list has a cost, do it lazily
             self._set = data
             # set has no order we pick one for stability purpose
             self._ascending = True
         else:
             if not isinstance(data, list):
                 data = list(data)
             self._list = data
         self._datarepr = datarepr
 
     @util.propertycache
     def _set(self):
         return set(self._list)
 
     @util.propertycache
     def _asclist(self):
         asclist = self._list[:]
         asclist.sort()
         return asclist
 
     @util.propertycache
     def _list(self):
         # _list is only lazily constructed if we have _set
         assert r'_set' in self.__dict__
         return list(self._set)
 
     def __iter__(self):
         if self._ascending is None:
             return iter(self._list)
         elif self._ascending:
             return iter(self._asclist)
         else:
             return reversed(self._asclist)
 
     def fastasc(self):
         return iter(self._asclist)
 
     def fastdesc(self):
         return reversed(self._asclist)
 
     @util.propertycache
     def __contains__(self):
         return self._set.__contains__
 
     def __nonzero__(self):
         return bool(len(self))
 
     __bool__ = __nonzero__
 
     def sort(self, reverse=False):
         self._ascending = not bool(reverse)
         self._istopo = False
 
     def reverse(self):
         if self._ascending is None:
             self._list.reverse()
         else:
             self._ascending = not self._ascending
         self._istopo = False
 
     def __len__(self):
         if r'_list' in self.__dict__:
             return len(self._list)
         else:
             return len(self._set)
 
     def isascending(self):
         """Returns True if the collection is ascending order, False if not.
 
         This is part of the mandatory API for smartset."""
         if len(self) <= 1:
             return True
         return self._ascending is not None and self._ascending
 
     def isdescending(self):
         """Returns True if the collection is descending order, False if not.
 
         This is part of the mandatory API for smartset."""
         if len(self) <= 1:
             return True
         return self._ascending is not None and not self._ascending
 
     def istopo(self):
         """Is the collection is in topographical order or not.
 
         This is part of the mandatory API for smartset."""
         if len(self) <= 1:
             return True
         return self._istopo
 
     def first(self):
         if self:
             if self._ascending is None:
                 return self._list[0]
             elif self._ascending:
                 return self._asclist[0]
             else:
                 return self._asclist[-1]
         return None
 
     def last(self):
         if self:
             if self._ascending is None:
                 return self._list[-1]
             elif self._ascending:
                 return self._asclist[-1]
             else:
                 return self._asclist[0]
         return None
 
     def _fastsetop(self, other, op):
         # try to use native set operations as fast paths
         if (type(other) is baseset and r'_set' in other.__dict__ and r'_set' in
             self.__dict__ and self._ascending is not None):
             s = baseset(data=getattr(self._set, op)(other._set),
                         istopo=self._istopo)
             s._ascending = self._ascending
         else:
             s = getattr(super(baseset, self), op)(other)
         return s
 
     def __and__(self, other):
         return self._fastsetop(other, '__and__')
 
     def __sub__(self, other):
         return self._fastsetop(other, '__sub__')
 
     def _slice(self, start, stop):
         # creating new list should be generally cheaper than iterating items
         if self._ascending is None:
             return baseset(self._list[start:stop], istopo=self._istopo)
 
         data = self._asclist
         if not self._ascending:
             start, stop = max(len(data) - stop, 0), max(len(data) - start, 0)
         s = baseset(data[start:stop], istopo=self._istopo)
         s._ascending = self._ascending
         return s
 
     @encoding.strmethod
     def __repr__(self):
         d = {None: '', False: '-', True: '+'}[self._ascending]
-        s = _formatsetrepr(self._datarepr)
+        s = stringutil.buildrepr(self._datarepr)
         if not s:
             l = self._list
             # if _list has been built from a set, it might have a different
             # order from one python implementation to another.
             # We fallback to the sorted version for a stable output.
             if self._ascending is not None:
                 l = self._asclist
             s = pycompat.byterepr(l)
         return '<%s%s %s>' % (_typename(self), d, s)
 
 class filteredset(abstractsmartset):
     """Duck type for baseset class which iterates lazily over the revisions in
     the subset and contains a function which tests for membership in the
     revset
     """
     def __init__(self, subset, condition=lambda x: True, condrepr=None):
         """
         condition: a function that decide whether a revision in the subset
                    belongs to the revset or not.
         condrepr: a tuple of (format, obj, ...), a function or an object that
                   provides a printable representation of the given condition.
         """
         self._subset = subset
         self._condition = condition
         self._condrepr = condrepr
 
     def __contains__(self, x):
         return x in self._subset and self._condition(x)
 
     def __iter__(self):
         return self._iterfilter(self._subset)
 
     def _iterfilter(self, it):
         cond = self._condition
         for x in it:
             if cond(x):
                 yield x
 
     @property
     def fastasc(self):
         it = self._subset.fastasc
         if it is None:
             return None
         return lambda: self._iterfilter(it())
 
     @property
     def fastdesc(self):
         it = self._subset.fastdesc
         if it is None:
             return None
         return lambda: self._iterfilter(it())
 
     def __nonzero__(self):
         fast = None
         candidates = [self.fastasc if self.isascending() else None,
                       self.fastdesc if self.isdescending() else None,
                       self.fastasc,
                       self.fastdesc]
         for candidate in candidates:
             if candidate is not None:
                 fast = candidate
                 break
 
         if fast is not None:
             it = fast()
         else:
             it = self
 
         for r in it:
             return True
         return False
 
     __bool__ = __nonzero__
 
     def __len__(self):
         # Basic implementation to be changed in future patches.
         # until this gets improved, we use generator expression
         # here, since list comprehensions are free to call __len__ again
         # causing infinite recursion
         l = baseset(r for r in self)
         return len(l)
 
     def sort(self, reverse=False):
         self._subset.sort(reverse=reverse)
 
     def reverse(self):
         self._subset.reverse()
 
     def isascending(self):
         return self._subset.isascending()
 
     def isdescending(self):
         return self._subset.isdescending()
 
     def istopo(self):
         return self._subset.istopo()
 
     def first(self):
         for x in self:
             return x
         return None
 
     def last(self):
         it = None
         if self.isascending():
             it = self.fastdesc
         elif self.isdescending():
             it = self.fastasc
         if it is not None:
             for x in it():
                 return x
             return None #empty case
         else:
             x = None
             for x in self:
                 pass
             return x
 
     @encoding.strmethod
     def __repr__(self):
         xs = [pycompat.byterepr(self._subset)]
-        s = _formatsetrepr(self._condrepr)
+        s = stringutil.buildrepr(self._condrepr)
         if s:
             xs.append(s)
         return '<%s %s>' % (_typename(self), ', '.join(xs))
 
 def _iterordered(ascending, iter1, iter2):
     """produce an ordered iteration from two iterators with the same order
 
     The ascending is used to indicated the iteration direction.
     """
     choice = max
     if ascending:
         choice = min
 
     val1 = None
     val2 = None
     try:
         # Consume both iterators in an ordered way until one is empty
         while True:
             if val1 is None:
                 val1 = next(iter1)
             if val2 is None:
                 val2 = next(iter2)
             n = choice(val1, val2)
             yield n
             if val1 == n:
                 val1 = None
             if val2 == n:
                 val2 = None
     except StopIteration:
         # Flush any remaining values and consume the other one
         it = iter2
         if val1 is not None:
             yield val1
             it = iter1
         elif val2 is not None:
             # might have been equality and both are empty
             yield val2
         for val in it:
             yield val
 
 class addset(abstractsmartset):
     """Represent the addition of two sets
 
     Wrapper structure for lazily adding two structures without losing much
     performance on the __contains__ method
 
     If the ascending attribute is set, that means the two structures are
     ordered in either an ascending or descending way. Therefore, we can add
     them maintaining the order by iterating over both at the same time
 
     >>> xs = baseset([0, 3, 2])
     >>> ys = baseset([5, 2, 4])
 
     >>> rs = addset(xs, ys)
     >>> bool(rs), 0 in rs, 1 in rs, 5 in rs, rs.first(), rs.last()
     (True, True, False, True, 0, 4)
     >>> rs = addset(xs, baseset([]))
     >>> bool(rs), 0 in rs, 1 in rs, rs.first(), rs.last()
     (True, True, False, 0, 2)
     >>> rs = addset(baseset([]), baseset([]))
     >>> bool(rs), 0 in rs, rs.first(), rs.last()
     (False, False, None, None)
 
     iterate unsorted:
     >>> rs = addset(xs, ys)
     >>> # (use generator because pypy could call len())
     >>> list(x for x in rs)  # without _genlist
     [0, 3, 2, 5, 4]
     >>> assert not rs._genlist
     >>> len(rs)
     5
     >>> [x for x in rs]  # with _genlist
     [0, 3, 2, 5, 4]
     >>> assert rs._genlist
 
     iterate ascending:
     >>> rs = addset(xs, ys, ascending=True)
     >>> # (use generator because pypy could call len())
     >>> list(x for x in rs), list(x for x in rs.fastasc())  # without _asclist
     ([0, 2, 3, 4, 5], [0, 2, 3, 4, 5])
     >>> assert not rs._asclist
     >>> len(rs)
     5
     >>> [x for x in rs], [x for x in rs.fastasc()]
     ([0, 2, 3, 4, 5], [0, 2, 3, 4, 5])
     >>> assert rs._asclist
 
     iterate descending:
     >>> rs = addset(xs, ys, ascending=False)
     >>> # (use generator because pypy could call len())
     >>> list(x for x in rs), list(x for x in rs.fastdesc())  # without _asclist
     ([5, 4, 3, 2, 0], [5, 4, 3, 2, 0])
     >>> assert not rs._asclist
     >>> len(rs)
     5
     >>> [x for x in rs], [x for x in rs.fastdesc()]
     ([5, 4, 3, 2, 0], [5, 4, 3, 2, 0])
     >>> assert rs._asclist
 
     iterate ascending without fastasc:
     >>> rs = addset(xs, generatorset(ys), ascending=True)
     >>> assert rs.fastasc is None
     >>> [x for x in rs]
     [0, 2, 3, 4, 5]
 
     iterate descending without fastdesc:
     >>> rs = addset(generatorset(xs), ys, ascending=False)
     >>> assert rs.fastdesc is None
     >>> [x for x in rs]
     [5, 4, 3, 2, 0]
     """
     def __init__(self, revs1, revs2, ascending=None):
         self._r1 = revs1
         self._r2 = revs2
         self._iter = None
         self._ascending = ascending
         self._genlist = None
         self._asclist = None
 
     def __len__(self):
         return len(self._list)
 
     def __nonzero__(self):
         return bool(self._r1) or bool(self._r2)
 
     __bool__ = __nonzero__
 
     @util.propertycache
     def _list(self):
         if not self._genlist:
             self._genlist = baseset(iter(self))
         return self._genlist
 
     def __iter__(self):
         """Iterate over both collections without repeating elements
 
         If the ascending attribute is not set, iterate over the first one and
         then over the second one checking for membership on the first one so we
         dont yield any duplicates.
 
         If the ascending attribute is set, iterate over both collections at the
         same time, yielding only one value at a time in the given order.
         """
         if self._ascending is None:
             if self._genlist:
                 return iter(self._genlist)
             def arbitraryordergen():
                 for r in self._r1:
                     yield r
                 inr1 = self._r1.__contains__
                 for r in self._r2:
                     if not inr1(r):
                         yield r
             return arbitraryordergen()
         # try to use our own fast iterator if it exists
         self._trysetasclist()
         if self._ascending:
             attr = 'fastasc'
         else:
             attr = 'fastdesc'
         it = getattr(self, attr)
         if it is not None:
             return it()
         # maybe half of the component supports fast
         # get iterator for _r1
         iter1 = getattr(self._r1, attr)
         if iter1 is None:
             # let's avoid side effect (not sure it matters)
             iter1 = iter(sorted(self._r1, reverse=not self._ascending))
         else:
             iter1 = iter1()
         # get iterator for _r2
         iter2 = getattr(self._r2, attr)
         if iter2 is None:
             # let's avoid side effect (not sure it matters)
             iter2 = iter(sorted(self._r2, reverse=not self._ascending))
         else:
             iter2 = iter2()
         return _iterordered(self._ascending, iter1, iter2)
 
     def _trysetasclist(self):
         """populate the _asclist attribute if possible and necessary"""
         if self._genlist is not None and self._asclist is None:
             self._asclist = sorted(self._genlist)
 
     @property
     def fastasc(self):
         self._trysetasclist()
         if self._asclist is not None:
             return self._asclist.__iter__
         iter1 = self._r1.fastasc
         iter2 = self._r2.fastasc
         if None in (iter1, iter2):
             return None
         return lambda: _iterordered(True, iter1(), iter2())
 
     @property
     def fastdesc(self):
         self._trysetasclist()
         if self._asclist is not None:
             return self._asclist.__reversed__
         iter1 = self._r1.fastdesc
         iter2 = self._r2.fastdesc
         if None in (iter1, iter2):
             return None
         return lambda: _iterordered(False, iter1(), iter2())
 
     def __contains__(self, x):
         return x in self._r1 or x in self._r2
 
     def sort(self, reverse=False):
         """Sort the added set
 
         For this we use the cached list with all the generated values and if we
         know they are ascending or descending we can sort them in a smart way.
         """
         self._ascending = not reverse
 
     def isascending(self):
         return self._ascending is not None and self._ascending
 
     def isdescending(self):
         return self._ascending is not None and not self._ascending
 
     def istopo(self):
         # not worth the trouble asserting if the two sets combined are still
         # in topographical order. Use the sort() predicate to explicitly sort
         # again instead.
         return False
 
     def reverse(self):
         if self._ascending is None:
             self._list.reverse()
         else:
             self._ascending = not self._ascending
 
     def first(self):
         for x in self:
             return x
         return None
 
     def last(self):
         self.reverse()
         val = self.first()
         self.reverse()
         return val
 
     @encoding.strmethod
     def __repr__(self):
         d = {None: '', False: '-', True: '+'}[self._ascending]
         return '<%s%s %r, %r>' % (_typename(self), d, self._r1, self._r2)
 
 class generatorset(abstractsmartset):
     """Wrap a generator for lazy iteration
 
     Wrapper structure for generators that provides lazy membership and can
     be iterated more than once.
     When asked for membership it generates values until either it finds the
     requested one or has gone through all the elements in the generator
 
     >>> xs = generatorset([0, 1, 4], iterasc=True)
     >>> assert xs.last() == xs.last()
     >>> xs.last()  # cached
     4
     """
     def __new__(cls, gen, iterasc=None):
         if iterasc is None:
             typ = cls
         elif iterasc:
             typ = _generatorsetasc
         else:
             typ = _generatorsetdesc
 
         return super(generatorset, cls).__new__(typ)
 
     def __init__(self, gen, iterasc=None):
         """
         gen: a generator producing the values for the generatorset.
         """
         self._gen = gen
         self._asclist = None
         self._cache = {}
         self._genlist = []
         self._finished = False
         self._ascending = True
 
     def __nonzero__(self):
         # Do not use 'for r in self' because it will enforce the iteration
         # order (default ascending), possibly unrolling a whole descending
         # iterator.
         if self._genlist:
             return True
         for r in self._consumegen():
             return True
         return False
 
     __bool__ = __nonzero__
 
     def __contains__(self, x):
         if x in self._cache:
             return self._cache[x]
 
         # Use new values only, as existing values would be cached.
         for l in self._consumegen():
             if l == x:
                 return True
 
         self._cache[x] = False
         return False
 
     def __iter__(self):
         if self._ascending:
             it = self.fastasc
         else:
             it = self.fastdesc
         if it is not None:
             return it()
         # we need to consume the iterator
         for x in self._consumegen():
             pass
         # recall the same code
         return iter(self)
 
     def _iterator(self):
         if self._finished:
             return iter(self._genlist)
 
         # We have to use this complex iteration strategy to allow multiple
         # iterations at the same time. We need to be able to catch revision
         # removed from _consumegen and added to genlist in another instance.
         #
         # Getting rid of it would provide an about 15% speed up on this
         # iteration.
         genlist = self._genlist
         nextgen = self._consumegen()
         _len, _next = len, next # cache global lookup
         def gen():
             i = 0
             while True:
                 if i < _len(genlist):
                     yield genlist[i]
                 else:
                     try:
                         yield _next(nextgen)
                     except StopIteration:
                         return
                 i += 1
         return gen()
 
     def _consumegen(self):
         cache = self._cache
         genlist = self._genlist.append
         for item in self._gen:
             cache[item] = True
             genlist(item)
             yield item
         if not self._finished:
             self._finished = True
             asc = self._genlist[:]
             asc.sort()
             self._asclist = asc
             self.fastasc = asc.__iter__
             self.fastdesc = asc.__reversed__
 
     def __len__(self):
         for x in self._consumegen():
             pass
         return len(self._genlist)
 
     def sort(self, reverse=False):
         self._ascending = not reverse
 
     def reverse(self):
         self._ascending = not self._ascending
 
     def isascending(self):
         return self._ascending
 
     def isdescending(self):
         return not self._ascending
 
     def istopo(self):
         # not worth the trouble asserting if the two sets combined are still
         # in topographical order. Use the sort() predicate to explicitly sort
         # again instead.
         return False
 
     def first(self):
         if self._ascending:
             it = self.fastasc
         else:
             it = self.fastdesc
         if it is None:
             # we need to consume all and try again
             for x in self._consumegen():
                 pass
             return self.first()
         return next(it(), None)
 
     def last(self):
         if self._ascending:
             it = self.fastdesc
         else:
             it = self.fastasc
         if it is None:
             # we need to consume all and try again
             for x in self._consumegen():
                 pass
             return self.last()
         return next(it(), None)
 
     @encoding.strmethod
     def __repr__(self):
         d = {False: '-', True: '+'}[self._ascending]
         return '<%s%s>' % (_typename(self), d)
 
 class _generatorsetasc(generatorset):
     """Special case of generatorset optimized for ascending generators."""
 
     fastasc = generatorset._iterator
 
     def __contains__(self, x):
         if x in self._cache:
             return self._cache[x]
 
         # Use new values only, as existing values would be cached.
         for l in self._consumegen():
             if l == x:
                 return True
             if l > x:
                 break
 
         self._cache[x] = False
         return False
 
 class _generatorsetdesc(generatorset):
     """Special case of generatorset optimized for descending generators."""
 
     fastdesc = generatorset._iterator
 
     def __contains__(self, x):
         if x in self._cache:
             return self._cache[x]
 
         # Use new values only, as existing values would be cached.
         for l in self._consumegen():
             if l == x:
                 return True
             if l < x:
                 break
 
         self._cache[x] = False
         return False
 
 def spanset(repo, start=0, end=None):
     """Create a spanset that represents a range of repository revisions
 
     start: first revision included the set (default to 0)
     end:   first revision excluded (last+1) (default to len(repo))
 
     Spanset will be descending if `end` < `start`.
     """
     if end is None:
         end = len(repo)
     ascending = start <= end
     if not ascending:
         start, end = end + 1, start + 1
     return _spanset(start, end, ascending, repo.changelog.filteredrevs)
 
 class _spanset(abstractsmartset):
     """Duck type for baseset class which represents a range of revisions and
     can work lazily and without having all the range in memory
 
     Note that spanset(x, y) behave almost like xrange(x, y) except for two
     notable points:
     - when x < y it will be automatically descending,
     - revision filtered with this repoview will be skipped.
 
     """
     def __init__(self, start, end, ascending, hiddenrevs):
         self._start = start
         self._end = end
         self._ascending = ascending
         self._hiddenrevs = hiddenrevs
 
     def sort(self, reverse=False):
         self._ascending = not reverse
 
     def reverse(self):
         self._ascending = not self._ascending
 
     def istopo(self):
         # not worth the trouble asserting if the two sets combined are still
         # in topographical order. Use the sort() predicate to explicitly sort
         # again instead.
         return False
 
     def _iterfilter(self, iterrange):
         s = self._hiddenrevs
         for r in iterrange:
             if r not in s:
                 yield r
 
     def __iter__(self):
         if self._ascending:
             return self.fastasc()
         else:
             return self.fastdesc()
 
     def fastasc(self):
         iterrange = xrange(self._start, self._end)
         if self._hiddenrevs:
             return self._iterfilter(iterrange)
         return iter(iterrange)
 
     def fastdesc(self):
         iterrange = xrange(self._end - 1, self._start - 1, -1)
         if self._hiddenrevs:
             return self._iterfilter(iterrange)
         return iter(iterrange)
 
     def __contains__(self, rev):
         hidden = self._hiddenrevs
         return ((self._start <= rev < self._end)
                 and not (hidden and rev in hidden))
 
     def __nonzero__(self):
         for r in self:
             return True
         return False
 
     __bool__ = __nonzero__
 
     def __len__(self):
         if not self._hiddenrevs:
             return abs(self._end - self._start)
         else:
             count = 0
             start = self._start
             end = self._end
             for rev in self._hiddenrevs:
                 if (end < rev <= start) or (start <= rev < end):
                     count += 1
             return abs(self._end - self._start) - count
 
     def isascending(self):
         return self._ascending
 
     def isdescending(self):
         return not self._ascending
 
     def first(self):
         if self._ascending:
             it = self.fastasc
         else:
             it = self.fastdesc
         for x in it():
             return x
         return None
 
     def last(self):
         if self._ascending:
             it = self.fastdesc
         else:
             it = self.fastasc
         for x in it():
             return x
         return None
 
     def _slice(self, start, stop):
         if self._hiddenrevs:
             # unoptimized since all hidden revisions in range has to be scanned
             return super(_spanset, self)._slice(start, stop)
         if self._ascending:
             x = min(self._start + start, self._end)
             y = min(self._start + stop, self._end)
         else:
             x = max(self._end - stop, self._start)
             y = max(self._end - start, self._start)
         return _spanset(x, y, self._ascending, self._hiddenrevs)
 
     @encoding.strmethod
     def __repr__(self):
         d = {False: '-', True: '+'}[self._ascending]
         return '<%s%s %d:%d>' % (_typename(self), d, self._start, self._end)
 
 class fullreposet(_spanset):
     """a set containing all revisions in the repo
 
     This class exists to host special optimization and magic to handle virtual
     revisions such as "null".
     """
 
     def __init__(self, repo):
         super(fullreposet, self).__init__(0, len(repo), True,
                                           repo.changelog.filteredrevs)
 
     def __and__(self, other):
         """As self contains the whole repo, all of the other set should also be
         in self. Therefore `self & other = other`.
 
         This boldly assumes the other contains valid revs only.
         """
         # other not a smartset, make is so
         if not util.safehasattr(other, 'isascending'):
             # filter out hidden revision
             # (this boldly assumes all smartset are pure)
             #
             # `other` was used with "&", let's assume this is a set like
             # object.
             other = baseset(other - self._hiddenrevs)
 
         other.sort(reverse=self.isdescending())
         return other

mercurial/utils/stringutil.py

@@ -1,560 +1,583 b''
 # stringutil.py - utility for generic string formatting, parsing, etc.
 #
 #  Copyright 2005 K. Thananchayan <[e-mail]>
 #  Copyright 2005-2007 Matt Mackall <[e-mail]>
 #  Copyright 2006 Vadim Gelfer <[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 ast
 import codecs
 import re as remod
 import textwrap
 
 from ..i18n import _
 from ..thirdparty import attr
 
 from .. import (
     encoding,
     error,
     pycompat,
 )
 
 # regex special chars pulled from https://bugs.python.org/issue29995
 # which was part of Python 3.7.
 _respecial = pycompat.bytestr(b'()[]{}?*+-|^$\\.&~# \t\n\r\v\f')
 _regexescapemap = {ord(i): (b'\\' + i).decode('latin1') for i in _respecial}
 
 def reescape(pat):
     """Drop-in replacement for re.escape."""
     # NOTE: it is intentional that this works on unicodes and not
     # bytes, as it's only possible to do the escaping with
     # unicode.translate, not bytes.translate. Sigh.
     wantuni = True
     if isinstance(pat, bytes):
         wantuni = False
         pat = pat.decode('latin1')
     pat = pat.translate(_regexescapemap)
     if wantuni:
         return pat
     return pat.encode('latin1')
 
 def pprint(o, bprefix=False):
     """Pretty print an object."""
     if isinstance(o, bytes):
         if bprefix:
             return "b'%s'" % escapestr(o)
         return "'%s'" % escapestr(o)
     elif isinstance(o, bytearray):
         # codecs.escape_encode() can't handle bytearray, so escapestr fails
         # without coercion.
         return "bytearray['%s']" % escapestr(bytes(o))
     elif isinstance(o, list):
         return '[%s]' % (b', '.join(pprint(a, bprefix=bprefix) for a in o))
     elif isinstance(o, dict):
         return '{%s}' % (b', '.join(
             '%s: %s' % (pprint(k, bprefix=bprefix),
                         pprint(v, bprefix=bprefix))
             for k, v in sorted(o.items())))
     elif isinstance(o, tuple):
         return '(%s)' % (b', '.join(pprint(a, bprefix=bprefix) for a in o))
     else:
         return pycompat.byterepr(o)
 
 def prettyrepr(o):
     """Pretty print a representation of a possibly-nested object"""
     lines = []
     rs = pycompat.byterepr(o)
     p0 = p1 = 0
     while p0 < len(rs):
         # '... field=<type ... field=<type ...'
         #      ~~~~~~~~~~~~~~~~
         #      p0    p1        q0    q1
         q0 = -1
         q1 = rs.find('<', p1 + 1)
         if q1 < 0:
             q1 = len(rs)
         elif q1 > p1 + 1 and rs.startswith('=', q1 - 1):
             # backtrack for ' field=<'
             q0 = rs.rfind(' ', p1 + 1, q1 - 1)
         if q0 < 0:
             q0 = q1
         else:
             q0 += 1  # skip ' '
         l = rs.count('<', 0, p0) - rs.count('>', 0, p0)
         assert l >= 0
         lines.append((l, rs[p0:q0].rstrip()))
         p0, p1 = q0, q1
     return '\n'.join('  ' * l + s for l, s in lines)
 
+def buildrepr(r):
+    """Format an optional printable representation from unexpanded bits
+
+    ========  =================================
+    type(r)   example
+    ========  =================================
+    tuple     ('<not %r>', other)
+    bytes     '<branch closed>'
+    callable  lambda: '<branch %r>' % sorted(b)
+    object    other
+    ========  =================================
+    """
+    if r is None:
+        return ''
+    elif isinstance(r, tuple):
+        return r[0] % pycompat.rapply(pycompat.maybebytestr, r[1:])
+    elif isinstance(r, bytes):
+        return r
+    elif callable(r):
+        return r()
+    else:
+        return pycompat.byterepr(r)
+
 def binary(s):
     """return true if a string is binary data"""
     return bool(s and '\0' in s)
 
 def stringmatcher(pattern, casesensitive=True):
     """
     accepts a string, possibly starting with 're:' or 'literal:' prefix.
     returns the matcher name, pattern, and matcher function.
     missing or unknown prefixes are treated as literal matches.
 
     helper for tests:
     >>> def test(pattern, *tests):
     ...     kind, pattern, matcher = stringmatcher(pattern)
     ...     return (kind, pattern, [bool(matcher(t)) for t in tests])
     >>> def itest(pattern, *tests):
     ...     kind, pattern, matcher = stringmatcher(pattern, casesensitive=False)
     ...     return (kind, pattern, [bool(matcher(t)) for t in tests])
 
     exact matching (no prefix):
     >>> test(b'abcdefg', b'abc', b'def', b'abcdefg')
     ('literal', 'abcdefg', [False, False, True])
 
     regex matching ('re:' prefix)
     >>> test(b're:a.+b', b'nomatch', b'fooadef', b'fooadefbar')
     ('re', 'a.+b', [False, False, True])
 
     force exact matches ('literal:' prefix)
     >>> test(b'literal:re:foobar', b'foobar', b're:foobar')
     ('literal', 're:foobar', [False, True])
 
     unknown prefixes are ignored and treated as literals
     >>> test(b'foo:bar', b'foo', b'bar', b'foo:bar')
     ('literal', 'foo:bar', [False, False, True])
 
     case insensitive regex matches
     >>> itest(b're:A.+b', b'nomatch', b'fooadef', b'fooadefBar')
     ('re', 'A.+b', [False, False, True])
 
     case insensitive literal matches
     >>> itest(b'ABCDEFG', b'abc', b'def', b'abcdefg')
     ('literal', 'ABCDEFG', [False, False, True])
     """
     if pattern.startswith('re:'):
         pattern = pattern[3:]
         try:
             flags = 0
             if not casesensitive:
                 flags = remod.I
             regex = remod.compile(pattern, flags)
         except remod.error as e:
             raise error.ParseError(_('invalid regular expression: %s')
                                    % e)
         return 're', pattern, regex.search
     elif pattern.startswith('literal:'):
         pattern = pattern[8:]
 
     match = pattern.__eq__
 
     if not casesensitive:
         ipat = encoding.lower(pattern)
         match = lambda s: ipat == encoding.lower(s)
     return 'literal', pattern, match
 
 def shortuser(user):
     """Return a short representation of a user name or email address."""
     f = user.find('@')
     if f >= 0:
         user = user[:f]
     f = user.find('<')
     if f >= 0:
         user = user[f + 1:]
     f = user.find(' ')
     if f >= 0:
         user = user[:f]
     f = user.find('.')
     if f >= 0:
         user = user[:f]
     return user
 
 def emailuser(user):
     """Return the user portion of an email address."""
     f = user.find('@')
     if f >= 0:
         user = user[:f]
     f = user.find('<')
     if f >= 0:
         user = user[f + 1:]
     return user
 
 def email(author):
     '''get email of author.'''
     r = author.find('>')
     if r == -1:
         r = None
     return author[author.find('<') + 1:r]
 
 def person(author):
     """Returns the name before an email address,
     interpreting it as per RFC 5322
 
     >>> person(b'foo@bar')
     'foo'
     >>> person(b'Foo Bar <foo@bar>')
     'Foo Bar'
     >>> person(b'"Foo Bar" <foo@bar>')
     'Foo Bar'
     >>> person(b'"Foo \"buz\" Bar" <foo@bar>')
     'Foo "buz" Bar'
     >>> # The following are invalid, but do exist in real-life
     ...
     >>> person(b'Foo "buz" Bar <foo@bar>')
     'Foo "buz" Bar'
     >>> person(b'"Foo Bar <foo@bar>')
     'Foo Bar'
     """
     if '@' not in author:
         return author
     f = author.find('<')
     if f != -1:
         return author[:f].strip(' "').replace('\\"', '"')
     f = author.find('@')
     return author[:f].replace('.', ' ')
 
 @attr.s(hash=True)
 class mailmapping(object):
     '''Represents a username/email key or value in
     a mailmap file'''
     email = attr.ib()
     name = attr.ib(default=None)
 
 def _ismailmaplineinvalid(names, emails):
     '''Returns True if the parsed names and emails
     in a mailmap entry are invalid.
 
     >>> # No names or emails fails
     >>> names, emails = [], []
     >>> _ismailmaplineinvalid(names, emails)
     True
     >>> # Only one email fails
     >>> emails = [b'[e-mail]']
     >>> _ismailmaplineinvalid(names, emails)
     True
     >>> # One email and one name passes
     >>> names = [b'Test Name']
     >>> _ismailmaplineinvalid(names, emails)
     False
     >>> # No names but two emails passes
     >>> names = []
     >>> emails = [b'[e-mail]', b'[e-mail]']
     >>> _ismailmaplineinvalid(names, emails)
     False
     '''
     return not emails or not names and len(emails) < 2
 
 def parsemailmap(mailmapcontent):
     """Parses data in the .mailmap format
 
     >>> mmdata = b"\\n".join([
     ... b'# Comment',
     ... b'Name <[e-mail]>',
     ... b'<[e-mail]> <[e-mail]>',
     ... b'Name <[e-mail]> <[e-mail]>',
     ... b'Name <[e-mail]> Commit <[e-mail]>',
     ... ])
     >>> mm = parsemailmap(mmdata)
     >>> for key in sorted(mm.keys()):
     ...     print(key)
     mailmapping(email='[e-mail]', name=None)
     mailmapping(email='[e-mail]', name=None)
     mailmapping(email='[e-mail]', name=None)
     mailmapping(email='[e-mail]', name='Commit')
     >>> for val in sorted(mm.values()):
     ...     print(val)
     mailmapping(email='[e-mail]', name='Name')
     mailmapping(email='[e-mail]', name=None)
     mailmapping(email='[e-mail]', name='Name')
     mailmapping(email='[e-mail]', name='Name')
     """
     mailmap = {}
 
     if mailmapcontent is None:
         return mailmap
 
     for line in mailmapcontent.splitlines():
 
         # Don't bother checking the line if it is a comment or
         # is an improperly formed author field
         if line.lstrip().startswith('#'):
             continue
 
         # names, emails hold the parsed emails and names for each line
         # name_builder holds the words in a persons name
         names, emails = [], []
         namebuilder = []
 
         for element in line.split():
             if element.startswith('#'):
                 # If we reach a comment in the mailmap file, move on
                 break
 
             elif element.startswith('<') and element.endswith('>'):
                 # We have found an email.
                 # Parse it, and finalize any names from earlier
                 emails.append(element[1:-1])  # Slice off the "<>"
 
                 if namebuilder:
                     names.append(' '.join(namebuilder))
                     namebuilder = []
 
                 # Break if we have found a second email, any other
                 # data does not fit the spec for .mailmap
                 if len(emails) > 1:
                     break
 
             else:
                 # We have found another word in the committers name
                 namebuilder.append(element)
 
         # Check to see if we have parsed the line into a valid form
         # We require at least one email, and either at least one
         # name or a second email
         if _ismailmaplineinvalid(names, emails):
             continue
 
         mailmapkey = mailmapping(
             email=emails[-1],
             name=names[-1] if len(names) == 2 else None,
         )
 
         mailmap[mailmapkey] = mailmapping(
             email=emails[0],
             name=names[0] if names else None,
         )
 
     return mailmap
 
 def mapname(mailmap, author):
     """Returns the author field according to the mailmap cache, or
     the original author field.
 
     >>> mmdata = b"\\n".join([
     ...     b'# Comment',
     ...     b'Name <[e-mail]>',
     ...     b'<[e-mail]> <[e-mail]>',
     ...     b'Name <[e-mail]> <[e-mail]>',
     ...     b'Name <[e-mail]> Commit <[e-mail]>',
     ... ])
     >>> m = parsemailmap(mmdata)
     >>> mapname(m, b'Commit <[e-mail]>')
     'Name <[e-mail]>'
     >>> mapname(m, b'Name <[e-mail]>')
     'Name <[e-mail]>'
     >>> mapname(m, b'Commit <[e-mail]>')
     'Name <[e-mail]>'
     >>> mapname(m, b'Commit <[e-mail]>')
     'Name <[e-mail]>'
     >>> mapname(m, b'Unknown Name <[e-mail]>')
     'Unknown Name <[e-mail]>'
     """
     # If the author field coming in isn't in the correct format,
     # or the mailmap is empty just return the original author field
     if not isauthorwellformed(author) or not mailmap:
         return author
 
     # Turn the user name into a mailmapping
     commit = mailmapping(name=person(author), email=email(author))
 
     try:
         # Try and use both the commit email and name as the key
         proper = mailmap[commit]
 
     except KeyError:
         # If the lookup fails, use just the email as the key instead
         # We call this commit2 as not to erase original commit fields
         commit2 = mailmapping(email=commit.email)
         proper = mailmap.get(commit2, mailmapping(None, None))
 
     # Return the author field with proper values filled in
     return '%s <%s>' % (
         proper.name if proper.name else commit.name,
         proper.email if proper.email else commit.email,
     )
 
 _correctauthorformat = remod.compile(br'^[^<]+\s\<[^<>]+@[^<>]+\>$')
 
 def isauthorwellformed(author):
     '''Return True if the author field is well formed
     (ie "Contributor Name <[e-mail]>")
 
     >>> isauthorwellformed(b'Good Author <[e-mail]>')
     True
     >>> isauthorwellformed(b'Author <[e-mail]>')
     True
     >>> isauthorwellformed(b'Bad Author')
     False
     >>> isauthorwellformed(b'Bad Author <[e-mail]')
     False
     >>> isauthorwellformed(b'Bad Author [e-mail]')
     False
     >>> isauthorwellformed(b'<[e-mail]>')
     False
     >>> isauthorwellformed(b'Bad Author <author>')
     False
     '''
     return _correctauthorformat.match(author) is not None
 
 def ellipsis(text, maxlength=400):
     """Trim string to at most maxlength (default: 400) columns in display."""
     return encoding.trim(text, maxlength, ellipsis='...')
 
 def escapestr(s):
     # call underlying function of s.encode('string_escape') directly for
     # Python 3 compatibility
     return codecs.escape_encode(s)[0]
 
 def unescapestr(s):
     return codecs.escape_decode(s)[0]
 
 def forcebytestr(obj):
     """Portably format an arbitrary object (e.g. exception) into a byte
     string."""
     try:
         return pycompat.bytestr(obj)
     except UnicodeEncodeError:
         # non-ascii string, may be lossy
         return pycompat.bytestr(encoding.strtolocal(str(obj)))
 
 def uirepr(s):
     # Avoid double backslash in Windows path repr()
     return pycompat.byterepr(pycompat.bytestr(s)).replace(b'\\\\', b'\\')
 
 # delay import of textwrap
 def _MBTextWrapper(**kwargs):
     class tw(textwrap.TextWrapper):
         """
         Extend TextWrapper for width-awareness.
 
         Neither number of 'bytes' in any encoding nor 'characters' is
         appropriate to calculate terminal columns for specified string.
 
         Original TextWrapper implementation uses built-in 'len()' directly,
         so overriding is needed to use width information of each characters.
 
         In addition, characters classified into 'ambiguous' width are
         treated as wide in East Asian area, but as narrow in other.
 
         This requires use decision to determine width of such characters.
         """
         def _cutdown(self, ucstr, space_left):
             l = 0
             colwidth = encoding.ucolwidth
             for i in xrange(len(ucstr)):
                 l += colwidth(ucstr[i])
                 if space_left < l:
                     return (ucstr[:i], ucstr[i:])
             return ucstr, ''
 
         # overriding of base class
         def _handle_long_word(self, reversed_chunks, cur_line, cur_len, width):
             space_left = max(width - cur_len, 1)
 
             if self.break_long_words:
                 cut, res = self._cutdown(reversed_chunks[-1], space_left)
                 cur_line.append(cut)
                 reversed_chunks[-1] = res
             elif not cur_line:
                 cur_line.append(reversed_chunks.pop())
 
         # this overriding code is imported from TextWrapper of Python 2.6
         # to calculate columns of string by 'encoding.ucolwidth()'
         def _wrap_chunks(self, chunks):
             colwidth = encoding.ucolwidth
 
             lines = []
             if self.width <= 0:
                 raise ValueError("invalid width %r (must be > 0)" % self.width)
 
             # Arrange in reverse order so items can be efficiently popped
             # from a stack of chucks.
             chunks.reverse()
 
             while chunks:
 
                 # Start the list of chunks that will make up the current line.
                 # cur_len is just the length of all the chunks in cur_line.
                 cur_line = []
                 cur_len = 0
 
                 # Figure out which static string will prefix this line.
                 if lines:
                     indent = self.subsequent_indent
                 else:
                     indent = self.initial_indent
 
                 # Maximum width for this line.
                 width = self.width - len(indent)
 
                 # First chunk on line is whitespace -- drop it, unless this
                 # is the very beginning of the text (i.e. no lines started yet).
                 if self.drop_whitespace and chunks[-1].strip() == r'' and lines:
                     del chunks[-1]
 
                 while chunks:
                     l = colwidth(chunks[-1])
 
                     # Can at least squeeze this chunk onto the current line.
                     if cur_len + l <= width:
                         cur_line.append(chunks.pop())
                         cur_len += l
 
                     # Nope, this line is full.
                     else:
                         break
 
                 # The current line is full, and the next chunk is too big to
                 # fit on *any* line (not just this one).
                 if chunks and colwidth(chunks[-1]) > width:
                     self._handle_long_word(chunks, cur_line, cur_len, width)
 
                 # If the last chunk on this line is all whitespace, drop it.
                 if (self.drop_whitespace and
                     cur_line and cur_line[-1].strip() == r''):
                     del cur_line[-1]
 
                 # Convert current line back to a string and store it in list
                 # of all lines (return value).
                 if cur_line:
                     lines.append(indent + r''.join(cur_line))
 
             return lines
 
     global _MBTextWrapper
     _MBTextWrapper = tw
     return tw(**kwargs)
 
 def wrap(line, width, initindent='', hangindent=''):
     maxindent = max(len(hangindent), len(initindent))
     if width <= maxindent:
         # adjust for weird terminal size
         width = max(78, maxindent + 1)
     line = line.decode(pycompat.sysstr(encoding.encoding),
                        pycompat.sysstr(encoding.encodingmode))
     initindent = initindent.decode(pycompat.sysstr(encoding.encoding),
                                    pycompat.sysstr(encoding.encodingmode))
     hangindent = hangindent.decode(pycompat.sysstr(encoding.encoding),
                                    pycompat.sysstr(encoding.encodingmode))
     wrapper = _MBTextWrapper(width=width,
                              initial_indent=initindent,
                              subsequent_indent=hangindent)
     return wrapper.fill(line).encode(pycompat.sysstr(encoding.encoding))
 
 _booleans = {'1': True, 'yes': True, 'true': True, 'on': True, 'always': True,
              '0': False, 'no': False, 'false': False, 'off': False,
              'never': False}
 
 def parsebool(s):
     """Parse s into a boolean.
 
     If s is not a valid boolean, returns None.
     """
     return _booleans.get(s.lower(), None)
 
 def evalpythonliteral(s):
     """Evaluate a string containing a Python literal expression"""
     # We could backport our tokenizer hack to rewrite '' to u'' if we want
     if pycompat.ispy3:
         return ast.literal_eval(s.decode('latin1'))
     return ast.literal_eval(s)