Docserver: Implement the content providers infrastructure, where a

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

Index: chrome/common/extensions/docs/server2/content_providers.py
diff --git a/chrome/common/extensions/docs/server2/content_providers.py b/chrome/common/extensions/docs/server2/content_providers.py
new file mode 100644
index 0000000000000000000000000000000000000000..9f75f0817a3619b91809bfde50f9c30d4add5109
--- /dev/null
+++ b/chrome/common/extensions/docs/server2/content_providers.py
@@ -0,0 +1,90 @@
+# Copyright 2013 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
+from operator import itemgetter
+import posixpath
+
+from chroot_file_system import ChrootFileSystem
+from content_provider import ContentProvider
+from svn_constants import JSON_PATH
+from third_party.json_schema_compiler.memoize import memoize
+
+
+_CONFIG_PATH = '%s/content_providers.json' % JSON_PATH
+
+
+class ContentProviders(object):
+  '''Implements the content_providers.json configuration; see
+  chrome/common/extensions/docs/templates/json/content_providers.json for its
+  current state and a description of the format.
+
+  Returns ContentProvider instances based on how they're configured there.
+  '''
+
+  def __init__(self, compiled_fs_factory, host_file_system):
+    self._compiled_fs_factory = compiled_fs_factory
+    self._host_file_system = host_file_system
+    self._cache = compiled_fs_factory.ForJson(host_file_system)
+
+  @memoize
+  def GetByName(self, name):
+    '''Gets the ContentProvider keyed by |name| in content_providers.json, or
+    None of there is no such content provider.
+    '''
+    config = self._GetConfig().get(name)
+    if config is None:
+      logging.error('No content provider found with name "%s"' % name)
+      return None
+    return self._CreateContentProvider(name, config)
+
+  @memoize
+  def GetByServlet(self, path):
+    '''Gets a (content_provider, path_in_content_provider) tuple, where
+    content_provider is the ContentProvider with the longest "servlet" property

[Jeffrey Yasskin, 2013/11/04 23:45:21]

s/servlet/serveFrom/?

+    that is a subpath of |path|, and path_in_content_provider is the remainder
+    of |path|.
+
+    For example, if content provider A matches servlet "foo" and content
+    provider B matches servlet "foo/bar", GetByServlet("foo/bar/baz") will
+    return (B, "baz").
+
+    Returns (None, |path|) if there is no ContentProvider matching |path|.
+    '''
+    serve_from_to_config = dict(
+        (config['serveFrom'], (name, config))
+        for name, config in self._GetConfig().iteritems())
+    path_parts = path.split('/')
+    for i in xrange(len(path_parts), -1, -1):
+      name_and_config = serve_from_to_config.get('/'.join(path_parts[:i]))
+      if name_and_config is not None:
+        return (self._CreateContentProvider(name_and_config[0],
+                                            name_and_config[1]),
+                '/'.join(path_parts[i:]))
+    return None, path
+
+  def _GetConfig(self):
+    return self._cache.GetFromFile(_CONFIG_PATH).Get()
+
+  def _CreateContentProvider(self, name, config):
+    type_ = config.get('type')
+    chroot = config.get('chroot', '')
+    supports_templates = config.get('supportsTemplates', False)
+    supports_zip = config.get('supportsZip', False)
+
+    if type_ == 'chromium':
+      file_system = self._host_file_system
+    else:
+      logging.error('Content provider type "%s" not supported', type_)
+      return None
+
+    return ContentProvider(name,
+                           self._compiled_fs_factory,
+                           ChrootFileSystem(file_system, chroot),
+                           supports_templates=supports_templates,
+                           supports_zip=supports_zip)
+
+  def Cron(self):
+    for name, config in self._GetConfig().iteritems():
+      self._CreateContentProvider(name, config).Cron()