templater: preparse templates and cache

This breaks templates down into a list of literal and {} groups, with
group types preidentified.

mercurial/templater.py

@@ -1,266 +1,286 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 or any later version.
 
 from i18n import _
 import 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|...}.'''
 
     def __init__(self, loader, filters={}, defaults={}):
         self.loader = loader
         self.filters = filters
         self.defaults = defaults
         self.cache = {}
+        self.parsecache = {}
 
     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)]
+        if t not in self.parsecache:
+            tmpl = self.loader(t)
+            self.parsecache[t] = self._parse(tmpl)
+        parsed = self.parsecache[t]
+        iters = [self._process(parsed, 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 _format(self, expr, get, map):
         key, format = expr.split('%')
         v = get(key)
         if not hasattr(v, '__iter__'):
             raise SyntaxError(_("error expanding '%s%%%s'") % (key, format))
         lm = map.copy()
         for i in v:
             if isinstance(i, dict):
                 lm.update(i)
                 yield self.process(format, lm)
             else:
                 # v is not an iterable of dicts, this happen when 'key'
                 # has been fully expanded already and format is useless.
                 # If so, return the expanded value.
                 yield i
 
     def _filter(self, expr, get, map):
         if expr not in self.cache:
             parts = expr.split('|')
             val = parts[0]
             try:
                 filters = [self.filters[f] for f in parts[1:]]
             except KeyError, i:
                 raise SyntaxError(_("unknown filter '%s'") % i[0])
             def apply(get):
                 x = get(val)
                 for f in filters:
                     x = f(x)
                 return x
             self.cache[expr] = apply
         return self.cache[expr](get)
 
-    def _process(self, tmpl, map):
+    def _parse(self, tmpl):
+        '''preparse a template'''
+
+        parsed = []
+        pos, stop = 0, len(tmpl)
+        while pos < stop:
+            n = tmpl.find('{', pos)
+            if n < 0:
+                parsed.append(('', tmpl[pos:stop]))
+                break
+            if n > 0 and tmpl[n - 1] == '\\':
+                # escaped
+                parsed.append(('', tmpl[pos:n + 1]))
+                pos = n + 1
+                continue
+            if n > pos:
+                parsed.append(('', tmpl[pos:n]))
+
+            pos = n
+            n = tmpl.find('}', pos)
+            if n < 0:
+                # no closing
+                parsed.append(('', tmpl[pos:stop]))
+                break
+
+            expr = tmpl[pos + 1:n]
+            pos = n + 1
+
+            if '%' in expr:
+                parsed.append(('%', expr))
+            elif '|' in expr:
+                parsed.append(('|', expr))
+            else:
+                parsed.append(('g', expr))
+
+        return parsed
+
+    def _process(self, parsed, map):
         '''Render a template. Returns a generator.'''
 
         def get(key):
             v = map.get(key)
             if v is None:
                 v = self.defaults.get(key, '')
             if hasattr(v, '__call__'):
                 v = v(**map)
             return v
 
-        pos, stop = 0, len(tmpl)
-        while pos < stop:
-            n = tmpl.find('{', pos)
-            if n < 0:
-                yield tmpl[pos:stop]
-                break
-            if n > 0 and tmpl[n - 1] == '\\':
-                # escaped
-                yield tmpl[pos:n + 1]
-                pos = n + 1
-                continue
-            if n > pos:
-                yield tmpl[pos:n]
-
-            pos = n
-            n = tmpl.find('}', pos)
-            if n < 0:
-                # no closing
-                yield tmpl[pos:stop]
-                break
-
-            expr = tmpl[pos + 1:n]
-            pos = n + 1
-
-            if '%' in expr:
-                yield self._format(expr, get, map)
-            elif '|' in expr:
-                yield self._filter(expr, get, map)
-            else:
-                yield get(expr)
+        for t, e in parsed:
+            if not t:
+                yield e
+            elif t is '|':
+                yield self._filter(e, get, map)
+            elif t is '%':
+                yield self._format(e, get, map)
+            elif t is 'g':
+                yield get(e)
 
 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:
                 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] = open(self.map[t][1]).read()
             except IOError, inst:
                 raise IOError(inst.args[0], _('template file %s: %s') %
                               (self.map[t][1], inst.args[1]))
         return self.cache[t]
 
     def __call__(self, t, **map):
         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(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 = templatepath()
     elif isinstance(paths, str):
         paths = [paths]
 
     if isinstance(styles, str):
         styles = [styles]
 
     for style in styles:
         if not 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)