content_providers.py revision 0f1bc08d4cfcc34181b0b5cbf065c40f687bf740 
1# Copyright 2013 The Chromium Authors. All rights reserved.
2# Use of this source code is governed by a BSD-style license that can be
3# found in the LICENSE file.
4
5import logging
6from operator import itemgetter
7import posixpath
8
9from chroot_file_system import ChrootFileSystem
10from content_provider import ContentProvider
11from svn_constants import JSON_PATH
12from third_party.json_schema_compiler.memoize import memoize
13
14
15_CONFIG_PATH = '%s/content_providers.json' % JSON_PATH
16
17
18class ContentProviders(object):
19  '''Implements the content_providers.json configuration; see
20  chrome/common/extensions/docs/templates/json/content_providers.json for its
21  current state and a description of the format.
22
23  Returns ContentProvider instances based on how they're configured there.
24  '''
25
26  def __init__(self, compiled_fs_factory, host_file_system):
27    self._compiled_fs_factory = compiled_fs_factory
28    self._host_file_system = host_file_system
29    self._cache = compiled_fs_factory.ForJson(host_file_system)
30
31  @memoize
32  def GetByName(self, name):
33    '''Gets the ContentProvider keyed by |name| in content_providers.json, or
34    None of there is no such content provider.
35    '''
36    config = self._GetConfig().get(name)
37    if config is None:
38      logging.error('No content provider found with name "%s"' % name)
39      return None
40    return self._CreateContentProvider(name, config)
41
42  @memoize
43  def GetByServeFrom(self, path):
44    '''Gets a (content_provider, path_in_content_provider) tuple, where
45    content_provider is the ContentProvider with the longest "serveFrom"
46    property that is a subpath of |path|, and path_in_content_provider is the
47    remainder of |path|.
48
49    For example, if content provider A serves from "foo" and content provider B
50    serves from "foo/bar", GetByServeFrom("foo/bar/baz") will return (B, "baz").
51
52    Returns (None, |path|) if no ContentProvider serves from |path|.
53    '''
54    serve_from_to_config = dict(
55        (config['serveFrom'], (name, config))
56        for name, config in self._GetConfig().iteritems())
57    path_parts = path.split('/')
58    for i in xrange(len(path_parts), -1, -1):
59      name_and_config = serve_from_to_config.get('/'.join(path_parts[:i]))
60      if name_and_config is not None:
61        return (self._CreateContentProvider(name_and_config[0],
62                                            name_and_config[1]),
63                '/'.join(path_parts[i:]))
64    return None, path
65
66  def _GetConfig(self):
67    return self._cache.GetFromFile(_CONFIG_PATH).Get()
68
69  def _CreateContentProvider(self, name, config):
70    supports_templates = config.get('supportsTemplates', False)
71    supports_zip = config.get('supportsZip', False)
72
73    if 'chromium' in config:
74      chromium_config = config['chromium']
75      if 'dir' not in chromium_config:
76        logging.error('"chromium" must have a "dir" property')
77        return None
78      file_system = ChrootFileSystem(self._host_file_system,
79                                     chromium_config['dir'])
80    else:
81      logging.error('Content provider type "%s" not supported', type_)
82      return None
83
84    return ContentProvider(name,
85                           self._compiled_fs_factory,
86                           file_system,
87                           supports_templates=supports_templates,
88                           supports_zip=supports_zip)
89
90  def Cron(self):
91    for name, config in self._GetConfig().iteritems():
92      self._CreateContentProvider(name, config).Cron()
93