Mercurial > hg
view mercurial/templater.py @ 10845:9d8194c2fcbd
templater: preparse templates and cache
This breaks templates down into a list of literal and {} groups, with
group types preidentified.
author | Matt Mackall <mpm@selenic.com> |
---|---|
date | Mon, 05 Apr 2010 15:25:08 -0500 |
parents | b91c1804008e |
children | 594140b1e12d |
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# templater.py - template expansion for output # # Copyright 2005, 2006 Matt Mackall <mpm@selenic.com> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. from 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.''' 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 _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 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)