Die build.py, Die: Part 2 (LocalFetcher, Handlebar support, build script)

chrome/common/extensions/docs/server2/template_fetcher.py

+# Copyright (c) 2012 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import logging
+import os
+import time
+
+from third_party.handlebar import Handlebar
+
+# Cache templates for 5 minutes.
+CACHE_TIMEOUT = 300
+
+# Cached templates stored as (branch, path) -> (template, cache time)
+# The template cache is global so it will not be erased each time a new
+# TemplateFetcher is created.
+TEMPLATE_CACHE = {}
+
+class TemplateFetcher(object):
+  def __init__(self, branch, fetcher):
+    self._fetcher = fetcher
+    self._branch = branch
+
+  def __getitem__(self, path):
+    key = (self._branch, path)
+    if key in TEMPLATE_CACHE:
+      compiled_template, compile_time = TEMPLATE_CACHE[key]
+      if (time.clock() - compile_time) > CACHE_TIMEOUT:
+        TEMPLATE_CACHE.pop(key)
+    if key not in TEMPLATE_CACHE:
+      logging.info('Template cache miss for: ' + path)
+      try:
+        template = self._fetcher.FetchResource(self._branch, path).content
+        compiled_template = Handlebar(template)
+        TEMPLATE_CACHE[key] = (compiled_template, time.clock())
+      except:
+        return ''
+
+    return compiled_template