templater: make the templating engine pluggable to some extent

tests/test-template-engine

@@ -0,0 +1,35 b''
+#!/bin/sh
+
+cat > engine.py << EOF
+
+from mercurial import templater
+
+class mytemplater(object):
+    def __init__(self, loader, filters, defaults):
+        self.loader = loader
+
+    def process(self, t, map):
+        tmpl = self.loader(t)
+        for k, v in map.iteritems():
+            v = templater.stringify(v)
+            tmpl = tmpl.replace('{{%s}}' % k, v)
+        yield tmpl
+
+templater.engines['my'] = mytemplater
+EOF
+
+hg init test
+echo '[extensions]' > test/.hg/hgrc
+echo "engine = $PWD/engine.py" >> test/.hg/hgrc
+
+cd test
+cat > mymap << EOF
+changeset = my:changeset.txt
+EOF
+
+cat > changeset.txt << EOF
+{{rev}} {{node}} {{author}}
+EOF
+
+hg ci -Ama
+hg log --style=./mymap

tests/test-template-engine.out

@@ -0,0 +1,3 b''
+adding changeset.txt
+adding mymap
+0 97e5f848f0936960273bbf75be6388cd0350a32b test

mercurial/templater.py

@@ -1,211 +1,222 b''
 # 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, incorporated herein by reference.
 
 from i18n import _
 import re, sys, os
 import util, config, templatefilters
 
 path = ['templates', '../templates']
 stringify = templatefilters.stringify
 
 def parsestring(s, quoted=True):
     '''parse a string using simple c-like syntax.
     string must be in quotes if quoted is True.'''
     if quoted:
         if len(s) < 2 or s[0] != s[-1]:
             raise SyntaxError(_('unmatched quotes'))
         return s[1:-1].decode('string_escape')
 
     return s.decode('string_escape')
 
 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|...}.'''
 
     template_re = re.compile(r"(?:(?:#(?=[\w\|%]+#))|(?:{(?=[\w\|%]+})))"
                              r"(\w+)(?:(?:%(\w+))|((?:\|\w+)*))[#}]")
 
     def __init__(self, loader, filters={}, defaults={}):
         self.loader = loader
         self.filters = filters
         self.defaults = defaults
 
     def process(self, t, map):
         '''Perform expansion. t is name of map element to expand. map contains
         added elements for use during expansion. Is a generator.'''
         tmpl = self.loader(t)
         iters = [self._process(tmpl, map)]
         while iters:
             try:
                 item = iters[0].next()
             except StopIteration:
                 iters.pop(0)
                 continue
             if isinstance(item, str):
                 yield item
             elif item is None:
                 yield ''
             elif hasattr(item, '__iter__'):
                 iters.insert(0, iter(item))
             else:
                 yield str(item)
 
     def _process(self, tmpl, map):
         '''Render a template. Returns a generator.'''
         while tmpl:
             m = self.template_re.search(tmpl)
             if not m:
                 yield tmpl
                 break
 
             start, end = m.span(0)
             key, format, fl = m.groups()
 
             if start:
                 yield tmpl[:start]
             tmpl = tmpl[end:]
 
             if key in map:
                 v = map[key]
             else:
                 v = self.defaults.get(key, "")
             if callable(v):
                 v = v(**map)
             if format:
                 if not hasattr(v, '__iter__'):
                     raise SyntaxError(_("Error expanding '%s%%%s'")
                                       % (key, format))
                 lm = map.copy()
                 for i in v:
                     lm.update(i)
                     yield self.process(format, lm)
             else:
                 if fl:
                     for f in fl.split("|")[1:]:
                         v = self.filters[f](v)
                 yield v
 
+engines = {'default': engine}
+
 class templater(object):
 
     def __init__(self, mapfile, filters={}, defaults={}, cache={},
                  minchunk=1024, maxchunk=65536):
         '''set up template engine.
         mapfile is name of file to read map definitions from.
         filters is dict of functions. each transforms a value into another.
         defaults is dict of default map definitions.'''
         self.mapfile = mapfile or 'template'
         self.cache = cache.copy()
         self.map = {}
         self.base = (mapfile and os.path.dirname(mapfile)) or ''
         self.filters = templatefilters.filters.copy()
         self.filters.update(filters)
         self.defaults = defaults
         self.minchunk, self.maxchunk = minchunk, maxchunk
+        self.engines = {}
 
         if not mapfile:
             return
         if not os.path.exists(mapfile):
             raise util.Abort(_('style not found: %s') % mapfile)
 
         conf = config.config()
         conf.read(mapfile)
 
         for key, val in conf[''].items():
             if val[0] in "'\"":
                 try:
                     self.cache[key] = parsestring(val)
                 except SyntaxError, inst:
                     raise SyntaxError('%s: %s' %
                                       (conf.source('', key), inst.args[0]))
             else:
-                self.map[key] = os.path.join(self.base, val)
+                val = 'default', val
+                if ':' in val[1]:
+                    val = val[1].split(':', 1)
+                self.map[key] = val[0], os.path.join(self.base, val[1])
 
     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 not t in self.cache:
             try:
-                self.cache[t] = file(self.map[t]).read()
+                self.cache[t] = open(self.map[t][1]).read()
             except IOError, inst:
                 raise IOError(inst.args[0], _('template file %s: %s') %
-                              (self.map[t], inst.args[1]))
+                              (self.map[t][1], inst.args[1]))
         return self.cache[t]
 
     def __call__(self, t, **map):
-        proc = engine(self.load, self.filters, self.defaults)
+        ttype = t in self.map and self.map[t][0] or 'default'
+        proc = self.engines.get(ttype)
+        if proc is None:
+            proc = engines[ttype](self.load, self.filters, self.defaults)
+            self.engines[ttype] = proc
+
         stream = proc.process(t, map)
         if self.minchunk:
             stream = util.increasingchunks(stream, min=self.minchunk,
                                            max=self.maxchunk)
         return stream
 
 def templatepath(name=None):
     '''return location of template file or directory (if no name).
     returns None if not found.'''
     normpaths = []
 
     # executable version (py2exe) doesn't support __file__
     if hasattr(sys, 'frozen'):
         module = sys.executable
     else:
         module = __file__
     for f in path:
         if f.startswith('/'):
             p = f
         else:
             fl = f.split('/')
             p = os.path.join(os.path.dirname(module), *fl)
         if name:
             p = os.path.join(p, name)
         if name and os.path.exists(p):
             return os.path.normpath(p)
         elif os.path.isdir(p):
             normpaths.append(os.path.normpath(p))
 
     return normpaths
 
 def stylemap(style, 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 = templatepath()
     elif isinstance(paths, str):
         paths = [paths]
 
     locations = style and [os.path.join(style, "map"), "map-" + style] or []
     locations.append("map")
     for path in paths:
         for location in locations:
             mapfile = os.path.join(path, location)
             if os.path.isfile(mapfile):
                 return mapfile
 
     raise RuntimeError("No hgweb templates found in %r" % paths)