templater: add hook point to populate additional mapping items

The 'revcache' dict will be inserted by this hook.

mercurial/formatter.py

@@ -1,592 +1,595
 # formatter.py - generic output formatting for mercurial
 #
 # Copyright 2012 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.
 
 """Generic output formatting for Mercurial
 
 The formatter provides API to show data in various ways. The following
 functions should be used in place of ui.write():
 
 - fm.write() for unconditional output
 - fm.condwrite() to show some extra data conditionally in plain output
 - fm.context() to provide changectx to template output
 - fm.data() to provide extra data to JSON or template output
 - fm.plain() to show raw text that isn't provided to JSON or template output
 
 To show structured data (e.g. date tuples, dicts, lists), apply fm.format*()
 beforehand so the data is converted to the appropriate data type. Use
 fm.isplain() if you need to convert or format data conditionally which isn't
 supported by the formatter API.
 
 To build nested structure (i.e. a list of dicts), use fm.nested().
 
 See also https://www.mercurial-scm.org/wiki/GenericTemplatingPlan
 
 fm.condwrite() vs 'if cond:':
 
 In most cases, use fm.condwrite() so users can selectively show the data
 in template output. If it's costly to build data, use plain 'if cond:' with
 fm.write().
 
 fm.nested() vs fm.formatdict() (or fm.formatlist()):
 
 fm.nested() should be used to form a tree structure (a list of dicts of
 lists of dicts...) which can be accessed through template keywords, e.g.
 "{foo % "{bar % {...}} {baz % {...}}"}". On the other hand, fm.formatdict()
 exports a dict-type object to template, which can be accessed by e.g.
 "{get(foo, key)}" function.
 
 Doctest helper:
 
 >>> def show(fn, verbose=False, **opts):
 ...     import sys
 ...     from . import ui as uimod
 ...     ui = uimod.ui()
 ...     ui.verbose = verbose
 ...     ui.pushbuffer()
 ...     try:
 ...         return fn(ui, ui.formatter(pycompat.sysbytes(fn.__name__),
 ...                   pycompat.byteskwargs(opts)))
 ...     finally:
 ...         print(pycompat.sysstr(ui.popbuffer()), end='')
 
 Basic example:
 
 >>> def files(ui, fm):
 ...     files = [(b'foo', 123, (0, 0)), (b'bar', 456, (1, 0))]
 ...     for f in files:
 ...         fm.startitem()
 ...         fm.write(b'path', b'%s', f[0])
 ...         fm.condwrite(ui.verbose, b'date', b'  %s',
 ...                      fm.formatdate(f[2], b'%Y-%m-%d %H:%M:%S'))
 ...         fm.data(size=f[1])
 ...         fm.plain(b'\\n')
 ...     fm.end()
 >>> show(files)
 foo
 bar
 >>> show(files, verbose=True)
 foo  1970-01-01 00:00:00
 bar  1970-01-01 00:00:01
 >>> show(files, template=b'json')
 [
  {
   "date": [0, 0],
   "path": "foo",
   "size": 123
  },
  {
   "date": [1, 0],
   "path": "bar",
   "size": 456
  }
 ]
 >>> show(files, template=b'path: {path}\\ndate: {date|rfc3339date}\\n')
 path: foo
 date: 1970-01-01T00:00:00+00:00
 path: bar
 date: 1970-01-01T00:00:01+00:00
 
 Nested example:
 
 >>> def subrepos(ui, fm):
 ...     fm.startitem()
 ...     fm.write(b'reponame', b'[%s]\\n', b'baz')
 ...     files(ui, fm.nested(b'files'))
 ...     fm.end()
 >>> show(subrepos)
 [baz]
 foo
 bar
 >>> show(subrepos, template=b'{reponame}: {join(files % "{path}", ", ")}\\n')
 baz: foo, bar
 """
 
 from __future__ import absolute_import, print_function
 
 import collections
 import contextlib
 import itertools
 import os
 
 from .i18n import _
 from .node import (
     hex,
     short,
 )
 
 from . import (
     error,
     pycompat,
     templatefilters,
     templatekw,
     templater,
     templateutil,
     util,
 )
 from .utils import dateutil
 
 pickle = util.pickle
 
 class _nullconverter(object):
     '''convert non-primitive data types to be processed by formatter'''
 
     # set to True if context object should be stored as item
     storecontext = False
 
     @staticmethod
     def formatdate(date, fmt):
         '''convert date tuple to appropriate format'''
         return date
     @staticmethod
     def formatdict(data, key, value, fmt, sep):
         '''convert dict or key-value pairs to appropriate dict format'''
         # use plain dict instead of util.sortdict so that data can be
         # serialized as a builtin dict in pickle output
         return dict(data)
     @staticmethod
     def formatlist(data, name, fmt, sep):
         '''convert iterable to appropriate list format'''
         return list(data)
 
 class baseformatter(object):
     def __init__(self, ui, topic, opts, converter):
         self._ui = ui
         self._topic = topic
         self._style = opts.get("style")
         self._template = opts.get("template")
         self._converter = converter
         self._item = None
         # function to convert node to string suitable for this output
         self.hexfunc = hex
     def __enter__(self):
         return self
     def __exit__(self, exctype, excvalue, traceback):
         if exctype is None:
             self.end()
     def _showitem(self):
         '''show a formatted item once all data is collected'''
     def startitem(self):
         '''begin an item in the format list'''
         if self._item is not None:
             self._showitem()
         self._item = {}
     def formatdate(self, date, fmt='%a %b %d %H:%M:%S %Y %1%2'):
         '''convert date tuple to appropriate format'''
         return self._converter.formatdate(date, fmt)
     def formatdict(self, data, key='key', value='value', fmt=None, sep=' '):
         '''convert dict or key-value pairs to appropriate dict format'''
         return self._converter.formatdict(data, key, value, fmt, sep)
     def formatlist(self, data, name, fmt=None, sep=' '):
         '''convert iterable to appropriate list format'''
         # name is mandatory argument for now, but it could be optional if
         # we have default template keyword, e.g. {item}
         return self._converter.formatlist(data, name, fmt, sep)
     def context(self, **ctxs):
         '''insert context objects to be used to render template keywords'''
         ctxs = pycompat.byteskwargs(ctxs)
         assert all(k in {'ctx', 'fctx'} for k in ctxs)
         if self._converter.storecontext:
             self._item.update(ctxs)
     def data(self, **data):
         '''insert data into item that's not shown in default output'''
         data = pycompat.byteskwargs(data)
         self._item.update(data)
     def write(self, fields, deftext, *fielddata, **opts):
         '''do default text output while assigning data to item'''
         fieldkeys = fields.split()
         assert len(fieldkeys) == len(fielddata)
         self._item.update(zip(fieldkeys, fielddata))
     def condwrite(self, cond, fields, deftext, *fielddata, **opts):
         '''do conditional write (primarily for plain formatter)'''
         fieldkeys = fields.split()
         assert len(fieldkeys) == len(fielddata)
         self._item.update(zip(fieldkeys, fielddata))
     def plain(self, text, **opts):
         '''show raw text for non-templated mode'''
     def isplain(self):
         '''check for plain formatter usage'''
         return False
     def nested(self, field):
         '''sub formatter to store nested data in the specified field'''
         self._item[field] = data = []
         return _nestedformatter(self._ui, self._converter, data)
     def end(self):
         '''end output for the formatter'''
         if self._item is not None:
             self._showitem()
 
 def nullformatter(ui, topic):
     '''formatter that prints nothing'''
     return baseformatter(ui, topic, opts={}, converter=_nullconverter)
 
 class _nestedformatter(baseformatter):
     '''build sub items and store them in the parent formatter'''
     def __init__(self, ui, converter, data):
         baseformatter.__init__(self, ui, topic='', opts={}, converter=converter)
         self._data = data
     def _showitem(self):
         self._data.append(self._item)
 
 def _iteritems(data):
     '''iterate key-value pairs in stable order'''
     if isinstance(data, dict):
         return sorted(data.iteritems())
     return data
 
 class _plainconverter(object):
     '''convert non-primitive data types to text'''
 
     storecontext = False
 
     @staticmethod
     def formatdate(date, fmt):
         '''stringify date tuple in the given format'''
         return dateutil.datestr(date, fmt)
     @staticmethod
     def formatdict(data, key, value, fmt, sep):
         '''stringify key-value pairs separated by sep'''
         prefmt = pycompat.identity
         if fmt is None:
             fmt = '%s=%s'
             prefmt = pycompat.bytestr
         return sep.join(fmt % (prefmt(k), prefmt(v))
                         for k, v in _iteritems(data))
     @staticmethod
     def formatlist(data, name, fmt, sep):
         '''stringify iterable separated by sep'''
         prefmt = pycompat.identity
         if fmt is None:
             fmt = '%s'
             prefmt = pycompat.bytestr
         return sep.join(fmt % prefmt(e) for e in data)
 
 class plainformatter(baseformatter):
     '''the default text output scheme'''
     def __init__(self, ui, out, topic, opts):
         baseformatter.__init__(self, ui, topic, opts, _plainconverter)
         if ui.debugflag:
             self.hexfunc = hex
         else:
             self.hexfunc = short
         if ui is out:
             self._write = ui.write
         else:
             self._write = lambda s, **opts: out.write(s)
     def startitem(self):
         pass
     def data(self, **data):
         pass
     def write(self, fields, deftext, *fielddata, **opts):
         self._write(deftext % fielddata, **opts)
     def condwrite(self, cond, fields, deftext, *fielddata, **opts):
         '''do conditional write'''
         if cond:
             self._write(deftext % fielddata, **opts)
     def plain(self, text, **opts):
         self._write(text, **opts)
     def isplain(self):
         return True
     def nested(self, field):
         # nested data will be directly written to ui
         return self
     def end(self):
         pass
 
 class debugformatter(baseformatter):
     def __init__(self, ui, out, topic, opts):
         baseformatter.__init__(self, ui, topic, opts, _nullconverter)
         self._out = out
         self._out.write("%s = [\n" % self._topic)
     def _showitem(self):
         self._out.write('    %s,\n' % pycompat.byterepr(self._item))
     def end(self):
         baseformatter.end(self)
         self._out.write("]\n")
 
 class pickleformatter(baseformatter):
     def __init__(self, ui, out, topic, opts):
         baseformatter.__init__(self, ui, topic, opts, _nullconverter)
         self._out = out
         self._data = []
     def _showitem(self):
         self._data.append(self._item)
     def end(self):
         baseformatter.end(self)
         self._out.write(pickle.dumps(self._data))
 
 class jsonformatter(baseformatter):
     def __init__(self, ui, out, topic, opts):
         baseformatter.__init__(self, ui, topic, opts, _nullconverter)
         self._out = out
         self._out.write("[")
         self._first = True
     def _showitem(self):
         if self._first:
             self._first = False
         else:
             self._out.write(",")
 
         self._out.write("\n {\n")
         first = True
         for k, v in sorted(self._item.items()):
             if first:
                 first = False
             else:
                 self._out.write(",\n")
             u = templatefilters.json(v, paranoid=False)
             self._out.write('  "%s": %s' % (k, u))
         self._out.write("\n }")
     def end(self):
         baseformatter.end(self)
         self._out.write("\n]\n")
 
 class _templateconverter(object):
     '''convert non-primitive data types to be processed by templater'''
 
     storecontext = True
 
     @staticmethod
     def formatdate(date, fmt):
         '''return date tuple'''
         return date
     @staticmethod
     def formatdict(data, key, value, fmt, sep):
         '''build object that can be evaluated as either plain string or dict'''
         data = util.sortdict(_iteritems(data))
         def f():
             yield _plainconverter.formatdict(data, key, value, fmt, sep)
         return templateutil.hybriddict(data, key=key, value=value, fmt=fmt,
                                        gen=f)
     @staticmethod
     def formatlist(data, name, fmt, sep):
         '''build object that can be evaluated as either plain string or list'''
         data = list(data)
         def f():
             yield _plainconverter.formatlist(data, name, fmt, sep)
         return templateutil.hybridlist(data, name=name, fmt=fmt, gen=f)
 
 class templateformatter(baseformatter):
     def __init__(self, ui, out, topic, opts):
         baseformatter.__init__(self, ui, topic, opts, _templateconverter)
         self._out = out
         spec = lookuptemplate(ui, topic, opts.get('template', ''))
         self._tref = spec.ref
         self._t = loadtemplater(ui, spec, defaults=templatekw.keywords,
                                 resources=templateresources(ui),
                                 cache=templatekw.defaulttempl)
         self._parts = templatepartsmap(spec, self._t,
                                        ['docheader', 'docfooter', 'separator'])
         self._counter = itertools.count()
         self._renderitem('docheader', {})
 
     def _showitem(self):
         item = self._item.copy()
         item['index'] = index = next(self._counter)
         if index > 0:
             self._renderitem('separator', {})
         self._renderitem(self._tref, item)
 
     def _renderitem(self, part, item):
         if part not in self._parts:
             return
         ref = self._parts[part]
 
         props = {}
         # explicitly-defined fields precede templatekw
         props.update(item)
         if 'ctx' in item or 'fctx' in item:
             # but template resources must be always available
             props['revcache'] = {}
         self._out.write(self._t.render(ref, props))
 
     def end(self):
         baseformatter.end(self)
         self._renderitem('docfooter', {})
 
 templatespec = collections.namedtuple(r'templatespec',
                                       r'ref tmpl mapfile')
 
 def lookuptemplate(ui, topic, tmpl):
     """Find the template matching the given -T/--template spec 'tmpl'
 
     'tmpl' can be any of the following:
 
      - a literal template (e.g. '{rev}')
      - a map-file name or path (e.g. 'changelog')
      - a reference to [templates] in config file
      - a path to raw template file
 
     A map file defines a stand-alone template environment. If a map file
     selected, all templates defined in the file will be loaded, and the
     template matching the given topic will be rendered. Aliases won't be
     loaded from user config, but from the map file.
 
     If no map file selected, all templates in [templates] section will be
     available as well as aliases in [templatealias].
     """
 
     # looks like a literal template?
     if '{' in tmpl:
         return templatespec('', tmpl, None)
 
     # perhaps a stock style?
     if not os.path.split(tmpl)[0]:
         mapname = (templater.templatepath('map-cmdline.' + tmpl)
                    or templater.templatepath(tmpl))
         if mapname and os.path.isfile(mapname):
             return templatespec(topic, None, mapname)
 
     # perhaps it's a reference to [templates]
     if ui.config('templates', tmpl):
         return templatespec(tmpl, None, None)
 
     if tmpl == 'list':
         ui.write(_("available styles: %s\n") % templater.stylelist())
         raise error.Abort(_("specify a template"))
 
     # perhaps it's a path to a map or a template
     if ('/' in tmpl or '\\' in tmpl) and os.path.isfile(tmpl):
         # is it a mapfile for a style?
         if os.path.basename(tmpl).startswith("map-"):
             return templatespec(topic, None, os.path.realpath(tmpl))
         with util.posixfile(tmpl, 'rb') as f:
             tmpl = f.read()
         return templatespec('', tmpl, None)
 
     # constant string?
     return templatespec('', tmpl, None)
 
 def templatepartsmap(spec, t, partnames):
     """Create a mapping of {part: ref}"""
     partsmap = {spec.ref: spec.ref}  # initial ref must exist in t
     if spec.mapfile:
         partsmap.update((p, p) for p in partnames if p in t)
     elif spec.ref:
         for part in partnames:
             ref = '%s:%s' % (spec.ref, part)  # select config sub-section
             if ref in t:
                 partsmap[part] = ref
     return partsmap
 
 def loadtemplater(ui, spec, defaults=None, resources=None, cache=None):
     """Create a templater from either a literal template or loading from
     a map file"""
     assert not (spec.tmpl and spec.mapfile)
     if spec.mapfile:
         frommapfile = templater.templater.frommapfile
         return frommapfile(spec.mapfile, defaults=defaults, resources=resources,
                            cache=cache)
     return maketemplater(ui, spec.tmpl, defaults=defaults, resources=resources,
                          cache=cache)
 
 def maketemplater(ui, tmpl, defaults=None, resources=None, cache=None):
     """Create a templater from a string template 'tmpl'"""
     aliases = ui.configitems('templatealias')
     t = templater.templater(defaults=defaults, resources=resources,
                             cache=cache, aliases=aliases)
     t.cache.update((k, templater.unquotestring(v))
                    for k, v in ui.configitems('templates'))
     if tmpl:
         t.cache[''] = tmpl
     return t
 
 class templateresources(templater.resourcemapper):
     """Resource mapper designed for the default templatekw and function"""
 
     def __init__(self, ui, repo=None):
         self._resmap = {
             'cache': {},  # for templatekw/funcs to store reusable data
             'repo': repo,
             'ui': ui,
         }
 
     def availablekeys(self, context, mapping):
         return {k for k, g in self._gettermap.iteritems()
                 if g(self, context, mapping, k) is not None}
 
     def knownkeys(self):
         return self._knownkeys
 
     def lookup(self, context, mapping, key):
         get = self._gettermap.get(key)
         if not get:
             return None
         return get(self, context, mapping, key)
 
+    def populatemap(self, context, origmapping, newmapping):
+        return {}
+
     def _getsome(self, context, mapping, key):
         v = mapping.get(key)
         if v is not None:
             return v
         return self._resmap.get(key)
 
     def _getctx(self, context, mapping, key):
         ctx = mapping.get('ctx')
         if ctx is not None:
             return ctx
         fctx = mapping.get('fctx')
         if fctx is not None:
             return fctx.changectx()
 
     def _getrepo(self, context, mapping, key):
         ctx = self._getctx(context, mapping, 'ctx')
         if ctx is not None:
             return ctx.repo()
         return self._getsome(context, mapping, key)
 
     _gettermap = {
         'cache': _getsome,
         'ctx': _getctx,
         'fctx': _getsome,
         'repo': _getrepo,
         'revcache': _getsome,  # per-ctx cache; set later
         'ui': _getsome,
     }
     _knownkeys = set(_gettermap.keys())
 
 def formatter(ui, out, topic, opts):
     template = opts.get("template", "")
     if template == "json":
         return jsonformatter(ui, out, topic, opts)
     elif template == "pickle":
         return pickleformatter(ui, out, topic, opts)
     elif template == "debug":
         return debugformatter(ui, out, topic, opts)
     elif template != "":
         return templateformatter(ui, out, topic, opts)
     # developer config: ui.formatdebug
     elif ui.configbool('ui', 'formatdebug'):
         return debugformatter(ui, out, topic, opts)
     # deprecated config: ui.formatjson
     elif ui.configbool('ui', 'formatjson'):
         return jsonformatter(ui, out, topic, opts)
     return plainformatter(ui, out, topic, opts)
 
 @contextlib.contextmanager
 def openformatter(ui, filename, topic, opts):
     """Create a formatter that writes outputs to the specified file
 
     Must be invoked using the 'with' statement.
     """
     with util.posixfile(filename, 'wb') as out:
         with formatter(ui, out, topic, opts) as fm:
             yield fm
 
 @contextlib.contextmanager
 def _neverending(fm):
     yield fm
 
 def maybereopen(fm, filename, opts):
     """Create a formatter backed by file if filename specified, else return
     the given formatter
 
     Must be invoked using the 'with' statement. This will never call fm.end()
     of the given formatter.
     """
     if filename:
         return openformatter(fm._ui, filename, fm._topic, opts)
     else:
         return _neverending(fm)

mercurial/templater.py

@@ -1,897 +1,914
 # templater.py - template expansion for output
 #
 # Copyright 2005, 2006 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.
 
 """Slightly complicated template engine for commands and hgweb
 
 This module provides low-level interface to the template engine. See the
 formatter and cmdutil modules if you are looking for high-level functions
 such as ``cmdutil.rendertemplate(ctx, tmpl)``.
 
 Internal Data Types
 -------------------
 
 Template keywords and functions take a dictionary of current symbols and
 resources (a "mapping") and return result. Inputs and outputs must be one
 of the following data types:
 
 bytes
     a byte string, which is generally a human-readable text in local encoding.
 
 generator
     a lazily-evaluated byte string, which is a possibly nested generator of
     values of any printable types, and  will be folded by ``stringify()``
     or ``flatten()``.
 
     BUG: hgweb overloads this type for mappings (i.e. some hgweb keywords
     returns a generator of dicts.)
 
 None
     sometimes represents an empty value, which can be stringified to ''.
 
 True, False, int, float
     can be stringified as such.
 
 date tuple
     a (unixtime, offset) tuple, which produces no meaningful output by itself.
 
 hybrid
     represents a list/dict of printable values, which can also be converted
     to mappings by % operator.
 
 mappable
     represents a scalar printable value, also supports % operator.
 """
 
 from __future__ import absolute_import, print_function
 
 import abc
 import os
 
 from .i18n import _
 from . import (
     config,
     encoding,
     error,
     parser,
     pycompat,
     templatefilters,
     templatefuncs,
     templateutil,
     util,
 )
 from .utils import (
     stringutil,
 )
 
 # template parsing
 
 elements = {
     # token-type: binding-strength, primary, prefix, infix, suffix
     "(": (20, None, ("group", 1, ")"), ("func", 1, ")"), None),
     ".": (18, None, None, (".", 18), None),
     "%": (15, None, None, ("%", 15), None),
     "|": (15, None, None, ("|", 15), None),
     "*": (5, None, None, ("*", 5), None),
     "/": (5, None, None, ("/", 5), None),
     "+": (4, None, None, ("+", 4), None),
     "-": (4, None, ("negate", 19), ("-", 4), None),
     "=": (3, None, None, ("keyvalue", 3), None),
     ",": (2, None, None, ("list", 2), None),
     ")": (0, None, None, None, None),
     "integer": (0, "integer", None, None, None),
     "symbol": (0, "symbol", None, None, None),
     "string": (0, "string", None, None, None),
     "template": (0, "template", None, None, None),
     "end": (0, None, None, None, None),
 }
 
 def tokenize(program, start, end, term=None):
     """Parse a template expression into a stream of tokens, which must end
     with term if specified"""
     pos = start
     program = pycompat.bytestr(program)
     while pos < end:
         c = program[pos]
         if c.isspace(): # skip inter-token whitespace
             pass
         elif c in "(=,).%|+-*/": # handle simple operators
             yield (c, None, pos)
         elif c in '"\'': # handle quoted templates
             s = pos + 1
             data, pos = _parsetemplate(program, s, end, c)
             yield ('template', data, s)
             pos -= 1
         elif c == 'r' and program[pos:pos + 2] in ("r'", 'r"'):
             # handle quoted strings
             c = program[pos + 1]
             s = pos = pos + 2
             while pos < end: # find closing quote
                 d = program[pos]
                 if d == '\\': # skip over escaped characters
                     pos += 2
                     continue
                 if d == c:
                     yield ('string', program[s:pos], s)
                     break
                 pos += 1
             else:
                 raise error.ParseError(_("unterminated string"), s)
         elif c.isdigit():
             s = pos
             while pos < end:
                 d = program[pos]
                 if not d.isdigit():
                     break
                 pos += 1
             yield ('integer', program[s:pos], s)
             pos -= 1
         elif (c == '\\' and program[pos:pos + 2] in (br"\'", br'\"')
               or c == 'r' and program[pos:pos + 3] in (br"r\'", br'r\"')):
             # handle escaped quoted strings for compatibility with 2.9.2-3.4,
             # where some of nested templates were preprocessed as strings and
             # then compiled. therefore, \"...\" was allowed. (issue4733)
             #
             # processing flow of _evalifliteral() at 5ab28a2e9962:
             # outer template string    -> stringify()  -> compiletemplate()
             # ------------------------    ------------    ------------------
             # {f("\\\\ {g(\"\\\"\")}"}    \\ {g("\"")}    [r'\\', {g("\"")}]
             #             ~~~~~~~~
             #             escaped quoted string
             if c == 'r':
                 pos += 1
                 token = 'string'
             else:
                 token = 'template'
             quote = program[pos:pos + 2]
             s = pos = pos + 2
             while pos < end: # find closing escaped quote
                 if program.startswith('\\\\\\', pos, end):
                     pos += 4 # skip over double escaped characters
                     continue
                 if program.startswith(quote, pos, end):
                     # interpret as if it were a part of an outer string
                     data = parser.unescapestr(program[s:pos])
                     if token == 'template':
                         data = _parsetemplate(data, 0, len(data))[0]
                     yield (token, data, s)
                     pos += 1
                     break
                 pos += 1
             else:
                 raise error.ParseError(_("unterminated string"), s)
         elif c.isalnum() or c in '_':
             s = pos
             pos += 1
             while pos < end: # find end of symbol
                 d = program[pos]
                 if not (d.isalnum() or d == "_"):
                     break
                 pos += 1
             sym = program[s:pos]
             yield ('symbol', sym, s)
             pos -= 1
         elif c == term:
             yield ('end', None, pos)
             return
         else:
             raise error.ParseError(_("syntax error"), pos)
         pos += 1
     if term:
         raise error.ParseError(_("unterminated template expansion"), start)
     yield ('end', None, pos)
 
 def _parsetemplate(tmpl, start, stop, quote=''):
     r"""
     >>> _parsetemplate(b'foo{bar}"baz', 0, 12)
     ([('string', 'foo'), ('symbol', 'bar'), ('string', '"baz')], 12)
     >>> _parsetemplate(b'foo{bar}"baz', 0, 12, quote=b'"')
     ([('string', 'foo'), ('symbol', 'bar')], 9)
     >>> _parsetemplate(b'foo"{bar}', 0, 9, quote=b'"')
     ([('string', 'foo')], 4)
     >>> _parsetemplate(br'foo\"bar"baz', 0, 12, quote=b'"')
     ([('string', 'foo"'), ('string', 'bar')], 9)
     >>> _parsetemplate(br'foo\\"bar', 0, 10, quote=b'"')
     ([('string', 'foo\\')], 6)
     """
     parsed = []
     for typ, val, pos in _scantemplate(tmpl, start, stop, quote):
         if typ == 'string':
             parsed.append((typ, val))
         elif typ == 'template':
             parsed.append(val)
         elif typ == 'end':
             return parsed, pos
         else:
             raise error.ProgrammingError('unexpected type: %s' % typ)
     raise error.ProgrammingError('unterminated scanning of template')
 
 def scantemplate(tmpl, raw=False):
     r"""Scan (type, start, end) positions of outermost elements in template
 
     If raw=True, a backslash is not taken as an escape character just like
     r'' string in Python. Note that this is different from r'' literal in
     template in that no template fragment can appear in r'', e.g. r'{foo}'
     is a literal '{foo}', but ('{foo}', raw=True) is a template expression
     'foo'.
 
     >>> list(scantemplate(b'foo{bar}"baz'))
     [('string', 0, 3), ('template', 3, 8), ('string', 8, 12)]
     >>> list(scantemplate(b'outer{"inner"}outer'))
     [('string', 0, 5), ('template', 5, 14), ('string', 14, 19)]
     >>> list(scantemplate(b'foo\\{escaped}'))
     [('string', 0, 5), ('string', 5, 13)]
     >>> list(scantemplate(b'foo\\{escaped}', raw=True))
     [('string', 0, 4), ('template', 4, 13)]
     """
     last = None
     for typ, val, pos in _scantemplate(tmpl, 0, len(tmpl), raw=raw):
         if last:
             yield last + (pos,)
         if typ == 'end':
             return
         else:
             last = (typ, pos)
     raise error.ProgrammingError('unterminated scanning of template')
 
 def _scantemplate(tmpl, start, stop, quote='', raw=False):
     """Parse template string into chunks of strings and template expressions"""
     sepchars = '{' + quote
     unescape = [parser.unescapestr, pycompat.identity][raw]
     pos = start
     p = parser.parser(elements)
     try:
         while pos < stop:
             n = min((tmpl.find(c, pos, stop) for c in sepchars),
                     key=lambda n: (n < 0, n))
             if n < 0:
                 yield ('string', unescape(tmpl[pos:stop]), pos)
                 pos = stop
                 break
             c = tmpl[n:n + 1]
             bs = 0  # count leading backslashes
             if not raw:
                 bs = (n - pos) - len(tmpl[pos:n].rstrip('\\'))
             if bs % 2 == 1:
                 # escaped (e.g. '\{', '\\\{', but not '\\{')
                 yield ('string', unescape(tmpl[pos:n - 1]) + c, pos)
                 pos = n + 1
                 continue
             if n > pos:
                 yield ('string', unescape(tmpl[pos:n]), pos)
             if c == quote:
                 yield ('end', None, n + 1)
                 return
 
             parseres, pos = p.parse(tokenize(tmpl, n + 1, stop, '}'))
             if not tmpl.startswith('}', pos):
                 raise error.ParseError(_("invalid token"), pos)
             yield ('template', parseres, n)
             pos += 1
 
         if quote:
             raise error.ParseError(_("unterminated string"), start)
     except error.ParseError as inst:
         if len(inst.args) > 1:  # has location
             loc = inst.args[1]
             # Offset the caret location by the number of newlines before the
             # location of the error, since we will replace one-char newlines
             # with the two-char literal r'\n'.
             offset = tmpl[:loc].count('\n')
             tmpl = tmpl.replace('\n', br'\n')
             # 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 = (tmpl + '\n'
                          + ' ' * (loc + 1 + offset) + '^ ' + _('here'))
         raise
     yield ('end', None, pos)
 
 def _unnesttemplatelist(tree):
     """Expand list of templates to node tuple
 
     >>> def f(tree):
     ...     print(pycompat.sysstr(prettyformat(_unnesttemplatelist(tree))))
     >>> f((b'template', []))
     (string '')
     >>> f((b'template', [(b'string', b'foo')]))
     (string 'foo')
     >>> f((b'template', [(b'string', b'foo'), (b'symbol', b'rev')]))
     (template
       (string 'foo')
       (symbol 'rev'))
     >>> f((b'template', [(b'symbol', b'rev')]))  # template(rev) -> str
     (template
       (symbol 'rev'))
     >>> f((b'template', [(b'template', [(b'string', b'foo')])]))
     (string 'foo')
     """
     if not isinstance(tree, tuple):
         return tree
     op = tree[0]
     if op != 'template':
         return (op,) + tuple(_unnesttemplatelist(x) for x in tree[1:])
 
     assert len(tree) == 2
     xs = tuple(_unnesttemplatelist(x) for x in tree[1])
     if not xs:
         return ('string', '')  # empty template ""
     elif len(xs) == 1 and xs[0][0] == 'string':
         return xs[0]  # fast path for string with no template fragment "x"
     else:
         return (op,) + xs
 
 def parse(tmpl):
     """Parse template string into tree"""
     parsed, pos = _parsetemplate(tmpl, 0, len(tmpl))
     assert pos == len(tmpl), 'unquoted template should be consumed'
     return _unnesttemplatelist(('template', parsed))
 
 def _parseexpr(expr):
     """Parse a template expression into tree
 
     >>> _parseexpr(b'"foo"')
     ('string', 'foo')
     >>> _parseexpr(b'foo(bar)')
     ('func', ('symbol', 'foo'), ('symbol', 'bar'))
     >>> _parseexpr(b'foo(')
     Traceback (most recent call last):
       ...
     ParseError: ('not a prefix: end', 4)
     >>> _parseexpr(b'"foo" "bar"')
     Traceback (most recent call last):
       ...
     ParseError: ('invalid token', 7)
     """
     p = parser.parser(elements)
     tree, pos = p.parse(tokenize(expr, 0, len(expr)))
     if pos != len(expr):
         raise error.ParseError(_('invalid token'), pos)
     return _unnesttemplatelist(tree)
 
 def prettyformat(tree):
     return parser.prettyformat(tree, ('integer', 'string', 'symbol'))
 
 def compileexp(exp, context, curmethods):
     """Compile parsed template tree to (func, data) pair"""
     if not exp:
         raise error.ParseError(_("missing argument"))
     t = exp[0]
     if t in curmethods:
         return curmethods[t](exp, context)
     raise error.ParseError(_("unknown method '%s'") % t)
 
 # template evaluation
 
 def getsymbol(exp):
     if exp[0] == 'symbol':
         return exp[1]
     raise error.ParseError(_("expected a symbol, got '%s'") % exp[0])
 
 def getlist(x):
     if not x:
         return []
     if x[0] == 'list':
         return getlist(x[1]) + [x[2]]
     return [x]
 
 def gettemplate(exp, context):
     """Compile given template tree or load named template from map file;
     returns (func, data) pair"""
     if exp[0] in ('template', 'string'):
         return compileexp(exp, context, methods)
     if exp[0] == 'symbol':
         # unlike runsymbol(), here 'symbol' is always taken as template name
         # even if it exists in mapping. this allows us to override mapping
         # by web templates, e.g. 'changelogtag' is redefined in map file.
         return context._load(exp[1])
     raise error.ParseError(_("expected template specifier"))
 
 def _runrecursivesymbol(context, mapping, key):
     raise error.Abort(_("recursive reference '%s' in template") % key)
 
 def buildtemplate(exp, context):
     ctmpl = [compileexp(e, context, methods) for e in exp[1:]]
     return (templateutil.runtemplate, ctmpl)
 
 def buildfilter(exp, context):
     n = getsymbol(exp[2])
     if n in context._filters:
         filt = context._filters[n]
         arg = compileexp(exp[1], context, methods)
         return (templateutil.runfilter, (arg, filt))
     if n in context._funcs:
         f = context._funcs[n]
         args = _buildfuncargs(exp[1], context, methods, n, f._argspec)
         return (f, args)
     raise error.ParseError(_("unknown function '%s'") % n)
 
 def buildmap(exp, context):
     darg = compileexp(exp[1], context, methods)
     targ = gettemplate(exp[2], context)
     return (templateutil.runmap, (darg, targ))
 
 def buildmember(exp, context):
     darg = compileexp(exp[1], context, methods)
     memb = getsymbol(exp[2])
     return (templateutil.runmember, (darg, memb))
 
 def buildnegate(exp, context):
     arg = compileexp(exp[1], context, exprmethods)
     return (templateutil.runnegate, arg)
 
 def buildarithmetic(exp, context, func):
     left = compileexp(exp[1], context, exprmethods)
     right = compileexp(exp[2], context, exprmethods)
     return (templateutil.runarithmetic, (func, left, right))
 
 def buildfunc(exp, context):
     n = getsymbol(exp[1])
     if n in context._funcs:
         f = context._funcs[n]
         args = _buildfuncargs(exp[2], context, exprmethods, n, f._argspec)
         return (f, args)
     if n in context._filters:
         args = _buildfuncargs(exp[2], context, exprmethods, n, argspec=None)
         if len(args) != 1:
             raise error.ParseError(_("filter %s expects one argument") % n)
         f = context._filters[n]
         return (templateutil.runfilter, (args[0], f))
     raise error.ParseError(_("unknown function '%s'") % n)
 
 def _buildfuncargs(exp, context, curmethods, funcname, argspec):
     """Compile parsed tree of function arguments into list or dict of
     (func, data) pairs
 
     >>> context = engine(lambda t: (templateutil.runsymbol, t))
     >>> def fargs(expr, argspec):
     ...     x = _parseexpr(expr)
     ...     n = getsymbol(x[1])
     ...     return _buildfuncargs(x[2], context, exprmethods, n, argspec)
     >>> list(fargs(b'a(l=1, k=2)', b'k l m').keys())
     ['l', 'k']
     >>> args = fargs(b'a(opts=1, k=2)', b'**opts')
     >>> list(args.keys()), list(args[b'opts'].keys())
     (['opts'], ['opts', 'k'])
     """
     def compiledict(xs):
         return util.sortdict((k, compileexp(x, context, curmethods))
                              for k, x in xs.iteritems())
     def compilelist(xs):
         return [compileexp(x, context, curmethods) for x in xs]
 
     if not argspec:
         # filter or function with no argspec: return list of positional args
         return compilelist(getlist(exp))
 
     # function with argspec: return dict of named args
     _poskeys, varkey, _keys, optkey = argspec = parser.splitargspec(argspec)
     treeargs = parser.buildargsdict(getlist(exp), funcname, argspec,
                                     keyvaluenode='keyvalue', keynode='symbol')
     compargs = util.sortdict()
     if varkey:
         compargs[varkey] = compilelist(treeargs.pop(varkey))
     if optkey:
         compargs[optkey] = compiledict(treeargs.pop(optkey))
     compargs.update(compiledict(treeargs))
     return compargs
 
 def buildkeyvaluepair(exp, content):
     raise error.ParseError(_("can't use a key-value pair in this context"))
 
 # methods to interpret function arguments or inner expressions (e.g. {_(x)})
 exprmethods = {
     "integer": lambda e, c: (templateutil.runinteger, e[1]),
     "string": lambda e, c: (templateutil.runstring, e[1]),
     "symbol": lambda e, c: (templateutil.runsymbol, e[1]),
     "template": buildtemplate,
     "group": lambda e, c: compileexp(e[1], c, exprmethods),
     ".": buildmember,
     "|": buildfilter,
     "%": buildmap,
     "func": buildfunc,
     "keyvalue": buildkeyvaluepair,
     "+": lambda e, c: buildarithmetic(e, c, lambda a, b: a + b),
     "-": lambda e, c: buildarithmetic(e, c, lambda a, b: a - b),
     "negate": buildnegate,
     "*": lambda e, c: buildarithmetic(e, c, lambda a, b: a * b),
     "/": lambda e, c: buildarithmetic(e, c, lambda a, b: a // b),
     }
 
 # methods to interpret top-level template (e.g. {x}, {x|_}, {x % "y"})
 methods = exprmethods.copy()
 methods["integer"] = exprmethods["symbol"]  # '{1}' as variable
 
 class _aliasrules(parser.basealiasrules):
     """Parsing and expansion rule set of template aliases"""
     _section = _('template alias')
     _parse = staticmethod(_parseexpr)
 
     @staticmethod
     def _trygetfunc(tree):
         """Return (name, args) if tree is func(...) or ...|filter; otherwise
         None"""
         if tree[0] == 'func' and tree[1][0] == 'symbol':
             return tree[1][1], getlist(tree[2])
         if tree[0] == '|' and tree[2][0] == 'symbol':
             return tree[2][1], [tree[1]]
 
 def expandaliases(tree, aliases):
     """Return new tree of aliases are expanded"""
     aliasmap = _aliasrules.buildmap(aliases)
     return _aliasrules.expand(aliasmap, tree)
 
 # template engine
 
 def _flatten(thing):
     '''yield a single stream from a possibly nested set of iterators'''
     thing = templateutil.unwraphybrid(thing)
     if isinstance(thing, bytes):
         yield thing
     elif isinstance(thing, str):
         # We can only hit this on Python 3, and it's here to guard
         # against infinite recursion.
         raise error.ProgrammingError('Mercurial IO including templates is done'
                                      ' with bytes, not strings, got %r' % thing)
     elif thing is None:
         pass
     elif not util.safehasattr(thing, '__iter__'):
         yield pycompat.bytestr(thing)
     else:
         for i in thing:
             i = templateutil.unwraphybrid(i)
             if isinstance(i, bytes):
                 yield i
             elif i is None:
                 pass
             elif not util.safehasattr(i, '__iter__'):
                 yield pycompat.bytestr(i)
             else:
                 for j in _flatten(i):
                     yield j
 
 def unquotestring(s):
     '''unwrap quotes if any; otherwise returns unmodified string'''
     if len(s) < 2 or s[0] not in "'\"" or s[0] != s[-1]:
         return s
     return s[1:-1]
 
 class resourcemapper(object):
     """Mapper of internal template resources"""
 
     __metaclass__ = abc.ABCMeta
 
     @abc.abstractmethod
     def availablekeys(self, context, mapping):
         """Return a set of available resource keys based on the given mapping"""
 
     @abc.abstractmethod
     def knownkeys(self):
         """Return a set of supported resource keys"""
 
     @abc.abstractmethod
     def lookup(self, context, mapping, key):
         """Return a resource for the key if available; otherwise None"""
 
+    @abc.abstractmethod
+    def populatemap(self, context, origmapping, newmapping):
+        """Return a dict of additional mapping items which should be paired
+        with the given new mapping"""
+
 class nullresourcemapper(resourcemapper):
     def availablekeys(self, context, mapping):
         return set()
 
     def knownkeys(self):
         return set()
 
     def lookup(self, context, mapping, key):
         return None
 
+    def populatemap(self, context, origmapping, newmapping):
+        return {}
+
 class engine(object):
     '''template expansion engine.
 
     template expansion works like this. a map file contains key=value
     pairs. if value is quoted, it is treated as string. otherwise, it
     is treated as name of template file.
 
     templater is asked to expand a key in map. it looks up key, and
     looks for strings like this: {foo}. it expands {foo} by looking up
     foo in map, and substituting it. expansion is recursive: it stops
     when there is no more {foo} to replace.
 
     expansion also allows formatting and filtering.
 
     format uses key to expand each item in list. syntax is
     {key%format}.
 
     filter uses function to transform value. syntax is
     {key|filter1|filter2|...}.'''
 
     def __init__(self, loader, filters=None, defaults=None, resources=None,
                  aliases=()):
         self._loader = loader
         if filters is None:
             filters = {}
         self._filters = filters
         self._funcs = templatefuncs.funcs  # make this a parameter if needed
         if defaults is None:
             defaults = {}
         if resources is None:
             resources = nullresourcemapper()
         self._defaults = defaults
         self._resources = resources
         self._aliasmap = _aliasrules.buildmap(aliases)
         self._cache = {}  # key: (func, data)
 
     def overlaymap(self, origmapping, newmapping):
         """Create combined mapping from the original mapping and partial
         mapping to override the original"""
         # do not copy symbols which overrides the defaults depending on
         # new resources, so the defaults will be re-evaluated (issue5612)
         knownres = self._resources.knownkeys()
         newres = self._resources.availablekeys(self, newmapping)
         mapping = {k: v for k, v in origmapping.iteritems()
                    if (k in knownres  # not a symbol per self.symbol()
                        or newres.isdisjoint(self._defaultrequires(k)))}
         mapping.update(newmapping)
+        mapping.update(
+            self._resources.populatemap(self, origmapping, newmapping))
         return mapping
 
     def _defaultrequires(self, key):
         """Resource keys required by the specified default symbol function"""
         v = self._defaults.get(key)
         if v is None or not callable(v):
             return ()
         return getattr(v, '_requires', ())
 
     def symbol(self, mapping, key):
         """Resolve symbol to value or function; None if nothing found"""
         v = None
         if key not in self._resources.knownkeys():
             v = mapping.get(key)
         if v is None:
             v = self._defaults.get(key)
         return v
 
     def resource(self, mapping, key):
         """Return internal data (e.g. cache) used for keyword/function
         evaluation"""
         v = self._resources.lookup(self, mapping, key)
         if v is None:
             raise templateutil.ResourceUnavailable(
                 _('template resource not available: %s') % key)
         return v
 
     def _load(self, t):
         '''load, parse, and cache a template'''
         if t not in self._cache:
             # put poison to cut recursion while compiling 't'
             self._cache[t] = (_runrecursivesymbol, t)
             try:
                 x = parse(self._loader(t))
                 if self._aliasmap:
                     x = _aliasrules.expand(self._aliasmap, x)
                 self._cache[t] = compileexp(x, self, methods)
             except: # re-raises
                 del self._cache[t]
                 raise
         return self._cache[t]
 
     def preload(self, t):
         """Load, parse, and cache the specified template if available"""
         try:
             self._load(t)
             return True
         except templateutil.TemplateNotFound:
             return False
 
     def process(self, t, mapping):
         '''Perform expansion. t is name of map element to expand.
         mapping contains added elements for use during expansion. Is a
         generator.'''
         func, data = self._load(t)
+        # populate additional items only if they don't exist in the given
+        # mapping. this is slightly different from overlaymap() because the
+        # initial 'revcache' may contain pre-computed items.
+        extramapping = self._resources.populatemap(self, {}, mapping)
+        if extramapping:
+            extramapping.update(mapping)
+            mapping = extramapping
         return _flatten(func(self, mapping, data))
 
 engines = {'default': engine}
 
 def stylelist():
     paths = templatepaths()
     if not paths:
         return _('no templates found, try `hg debuginstall` for more info')
     dirlist = os.listdir(paths[0])
     stylelist = []
     for file in dirlist:
         split = file.split(".")
         if split[-1] in ('orig', 'rej'):
             continue
         if split[0] == "map-cmdline":
             stylelist.append(split[1])
     return ", ".join(sorted(stylelist))
 
 def _readmapfile(mapfile):
     """Load template elements from the given map file"""
     if not os.path.exists(mapfile):
         raise error.Abort(_("style '%s' not found") % mapfile,
                           hint=_("available styles: %s") % stylelist())
 
     base = os.path.dirname(mapfile)
     conf = config.config(includepaths=templatepaths())
     conf.read(mapfile, remap={'': 'templates'})
 
     cache = {}
     tmap = {}
     aliases = []
 
     val = conf.get('templates', '__base__')
     if val and val[0] not in "'\"":
         # treat as a pointer to a base class for this style
         path = util.normpath(os.path.join(base, val))
 
         # fallback check in template paths
         if not os.path.exists(path):
             for p in templatepaths():
                 p2 = util.normpath(os.path.join(p, val))
                 if os.path.isfile(p2):
                     path = p2
                     break
                 p3 = util.normpath(os.path.join(p2, "map"))
                 if os.path.isfile(p3):
                     path = p3
                     break
 
         cache, tmap, aliases = _readmapfile(path)
 
     for key, val in conf['templates'].items():
         if not val:
             raise error.ParseError(_('missing value'),
                                    conf.source('templates', key))
         if val[0] in "'\"":
             if val[0] != val[-1]:
                 raise error.ParseError(_('unmatched quotes'),
                                        conf.source('templates', key))
             cache[key] = unquotestring(val)
         elif key != '__base__':
             val = 'default', val
             if ':' in val[1]:
                 val = val[1].split(':', 1)
             tmap[key] = val[0], os.path.join(base, val[1])
     aliases.extend(conf['templatealias'].items())
     return cache, tmap, aliases
 
 class templater(object):
 
     def __init__(self, filters=None, defaults=None, resources=None,
                  cache=None, aliases=(), minchunk=1024, maxchunk=65536):
         """Create template engine optionally with preloaded template fragments
 
         - ``filters``: a dict of functions to transform a value into another.
         - ``defaults``: a dict of symbol values/functions; may be overridden
           by a ``mapping`` dict.
         - ``resources``: a resourcemapper object to look up internal data
           (e.g. cache), inaccessible from user template.
         - ``cache``: a dict of preloaded template fragments.
         - ``aliases``: a list of alias (name, replacement) pairs.
 
         self.cache may be updated later to register additional template
         fragments.
         """
         if filters is None:
             filters = {}
         if defaults is None:
             defaults = {}
         if cache is None:
             cache = {}
         self.cache = cache.copy()
         self.map = {}
         self.filters = templatefilters.filters.copy()
         self.filters.update(filters)
         self.defaults = defaults
         self._resources = resources
         self._aliases = aliases
         self.minchunk, self.maxchunk = minchunk, maxchunk
         self.ecache = {}
 
     @classmethod
     def frommapfile(cls, mapfile, filters=None, defaults=None, resources=None,
                     cache=None, minchunk=1024, maxchunk=65536):
         """Create templater from the specified map file"""
         t = cls(filters, defaults, resources, cache, [], minchunk, maxchunk)
         cache, tmap, aliases = _readmapfile(mapfile)
         t.cache.update(cache)
         t.map = tmap
         t._aliases = aliases
         return t
 
     def __contains__(self, key):
         return key in self.cache or key in self.map
 
     def load(self, t):
         '''Get the template for the given template name. Use a local cache.'''
         if t not in self.cache:
             try:
                 self.cache[t] = util.readfile(self.map[t][1])
             except KeyError as inst:
                 raise templateutil.TemplateNotFound(
                     _('"%s" not in template map') % inst.args[0])
             except IOError as inst:
                 reason = (_('template file %s: %s')
                           % (self.map[t][1],
                              stringutil.forcebytestr(inst.args[1])))
                 raise IOError(inst.args[0], encoding.strfromlocal(reason))
         return self.cache[t]
 
     def renderdefault(self, mapping):
         """Render the default unnamed template and return result as string"""
         return self.render('', mapping)
 
     def render(self, t, mapping):
         """Render the specified named template and return result as string"""
         return templateutil.stringify(self.generate(t, mapping))
 
     def generate(self, t, mapping):
         """Return a generator that renders the specified named template and
         yields chunks"""
         ttype = t in self.map and self.map[t][0] or 'default'
         if ttype not in self.ecache:
             try:
                 ecls = engines[ttype]
             except KeyError:
                 raise error.Abort(_('invalid template engine: %s') % ttype)
             self.ecache[ttype] = ecls(self.load, self.filters, self.defaults,
                                       self._resources, self._aliases)
         proc = self.ecache[ttype]
 
         stream = proc.process(t, mapping)
         if self.minchunk:
             stream = util.increasingchunks(stream, min=self.minchunk,
                                            max=self.maxchunk)
         return stream
 
 def templatepaths():
     '''return locations used for template files.'''
     pathsrel = ['templates']
     paths = [os.path.normpath(os.path.join(util.datapath, f))
              for f in pathsrel]
     return [p for p in paths if os.path.isdir(p)]
 
 def templatepath(name):
     '''return location of template file. returns None if not found.'''
     for p in templatepaths():
         f = os.path.join(p, name)
         if os.path.exists(f):
             return f
     return None
 
 def stylemap(styles, paths=None):
     """Return path to mapfile for a given style.
 
     Searches mapfile in the following locations:
     1. templatepath/style/map
     2. templatepath/map-style
     3. templatepath/map
     """
 
     if paths is None:
         paths = templatepaths()
     elif isinstance(paths, bytes):
         paths = [paths]
 
     if isinstance(styles, bytes):
         styles = [styles]
 
     for style in styles:
         # only plain name is allowed to honor template paths
         if (not style
             or style in (pycompat.oscurdir, pycompat.ospardir)
             or pycompat.ossep in style
             or pycompat.osaltsep and pycompat.osaltsep in style):
             continue
         locations = [os.path.join(style, 'map'), 'map-' + style]
         locations.append('map')
 
         for path in paths:
             for location in locations:
                 mapfile = os.path.join(path, location)
                 if os.path.isfile(mapfile):
                     return style, mapfile
 
     raise RuntimeError("No hgweb templates found in %r" % paths)