reference_resolver.py revision a3f6a49ab37290eeeb8db0f41ec0f1cb74a68be7 
1# Copyright (c) 2012 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
5from copy import deepcopy
6import logging
7import re
8import string
9
10from file_system import FileNotFoundError
11
12
13def _ClassifySchemaNode(node_name, api):
14  """Attempt to classify |node_name| in an API, determining whether |node_name|
15  refers to a type, function, event, or property in |api|.
16  """
17  if '.' in node_name:
18    node_name, rest = node_name.split('.', 1)
19  else:
20    rest = None
21  for key, group in [('types', 'type'),
22                     ('functions', 'method'),
23                     ('events', 'event'),
24                     ('properties', 'property')]:
25    for item in api.get(key, []):
26      if item['name'] == node_name:
27        if rest is not None:
28          ret = _ClassifySchemaNode(rest, item)
29          if ret is not None:
30            return ret
31        else:
32          return group, node_name
33  return None
34
35
36def _MakeKey(namespace, ref):
37  key = '%s/%s' % (namespace, ref)
38  # AppEngine doesn't like keys > 500, but there will be some other stuff
39  # that goes into this key, so truncate it earlier.  This shoudn't be
40  # happening anyway unless there's a bug, such as http://crbug.com/314102.
41  max_size = 256
42  if len(key) > max_size:
43    logging.error('Key was >%s characters: %s' % (max_size, key))
44    key = key[:max_size]
45  return key
46
47
48class ReferenceResolver(object):
49  """Resolves references to $ref's by searching through the APIs to find the
50  correct node.
51
52  $ref's have two forms:
53
54    $ref:api.node - Replaces the $ref with a link to node on the API page. The
55                    title is set to the name of the node.
56
57    $ref:[api.node The Title] - Same as the previous form but title is set to
58                                "The Title".
59  """
60
61  # Matches after a $ref: that doesn't have []s.
62  _bare_ref = re.compile('\w+(\.\w+)*')
63
64  class Factory(object):
65    def __init__(self,
66                 api_data_source_factory,
67                 api_models,
68                 object_store_creator):
69      self._api_data_source_factory = api_data_source_factory
70      self._api_models = api_models
71      self._object_store_creator = object_store_creator
72
73    def Create(self):
74      return ReferenceResolver(
75          self._api_data_source_factory.Create(None),
76          self._api_models,
77          self._object_store_creator.Create(ReferenceResolver))
78
79  def __init__(self, api_data_source, api_models, object_store):
80    self._api_data_source = api_data_source
81    self._api_models = api_models
82    self._object_store = object_store
83
84  def _GetRefLink(self, ref, api_list, namespace):
85    # Check nodes within each API the ref might refer to.
86    parts = ref.split('.')
87    for i, part in enumerate(parts):
88      api_name = '.'.join(parts[:i])
89      if api_name not in api_list:
90        continue
91      try:
92        api = self._api_data_source.get(api_name, disable_refs=True)
93      except FileNotFoundError:
94        continue
95      name = '.'.join(parts[i:])
96      # Attempt to find |name| in the API.
97      node_info = _ClassifySchemaNode(name, api)
98      if node_info is None:
99        # Check to see if this ref is a property. If it is, we want the ref to
100        # the underlying type the property is referencing.
101        for prop in api.get('properties', []):
102          # If the name of this property is in the ref text, replace the
103          # property with its type, and attempt to classify it.
104          if prop['name'] in name and 'link' in prop:
105            name_as_prop_type = name.replace(prop['name'], prop['link']['name'])
106            node_info = _ClassifySchemaNode(name_as_prop_type, api)
107            if node_info is not None:
108              name = name_as_prop_type
109              text = ref.replace(prop['name'], prop['link']['name'])
110              break
111        if node_info is None:
112          continue
113      else:
114        text = ref
115      category, node_name = node_info
116      if namespace is not None and text.startswith('%s.' % namespace):
117        text = text[len('%s.' % namespace):]
118      return {
119        'href': '%s.html#%s-%s' % (api_name, category, name.replace('.', '-')),
120        'text': text,
121        'name': node_name
122      }
123
124    # If it's not a reference to an API node it might just be a reference to an
125    # API. Check this last so that links within APIs take precedence over links
126    # to other APIs.
127    if ref in api_list:
128      return {
129        'href': '%s.html' % ref,
130        'text': ref,
131        'name': ref
132      }
133
134    return None
135
136  def GetLink(self, ref, namespace=None, title=None):
137    """Resolve $ref |ref| in namespace |namespace| if not None, returning None
138    if it cannot be resolved.
139    """
140    db_key = _MakeKey(namespace, ref)
141    link = self._object_store.Get(db_key).Get()
142    if link is None:
143      api_list = self._api_models.GetNames()
144      link = self._GetRefLink(ref, api_list, namespace)
145      if link is None and namespace is not None:
146        # Try to resolve the ref in the current namespace if there is one.
147        link = self._GetRefLink('%s.%s' % (namespace, ref), api_list, namespace)
148      if link is None:
149        return None
150      self._object_store.Set(db_key, link)
151    else:
152      link = deepcopy(link)
153    if title is not None:
154      link['text'] = title
155    return link
156
157  def SafeGetLink(self, ref, namespace=None, title=None):
158    """Resolve $ref |ref| in namespace |namespace|, or globally if None. If it
159    cannot be resolved, pretend like it is a link to a type.
160    """
161    ref_data = self.GetLink(ref, namespace=namespace, title=title)
162    if ref_data is not None:
163      return ref_data
164    logging.error('$ref %s could not be resolved in namespace %s.' %
165        (ref, namespace))
166    type_name = ref.rsplit('.', 1)[-1]
167    return {
168      'href': '#type-%s' % type_name,
169      'text': title or ref,
170      'name': ref
171    }
172
173  def ResolveAllLinks(self, text, relative_to='', namespace=None):
174    """This method will resolve all $ref links in |text| using namespace
175    |namespace| if not None. Any links that cannot be resolved will be replaced
176    using the default link format that |SafeGetLink| uses.
177    The links will be generated relative to |relative_to|.
178    """
179    if text is None or '$ref:' not in text:
180      return text
181
182    # requestPath should be of the form (apps|extensions)/...../page.html.
183    # link_prefix should  that the target will point to
184    # (apps|extensions)/target.html. Note multiplying a string by a negative
185    # number gives the empty string.
186    link_prefix = '../' * (relative_to.count('/') - 1)
187    split_text = text.split('$ref:')
188    # |split_text| is an array of text chunks that all start with the
189    # argument to '$ref:'.
190    formatted_text = [split_text[0]]
191    for ref_and_rest in split_text[1:]:
192      title = None
193      if ref_and_rest.startswith('[') and ']' in ref_and_rest:
194        # Text was '$ref:[foo.bar maybe title] other stuff'.
195        ref_with_title, rest = ref_and_rest[1:].split(']', 1)
196        ref_with_title = ref_with_title.split(None, 1)
197        if len(ref_with_title) == 1:
198          # Text was '$ref:[foo.bar] other stuff'.
199          ref = ref_with_title[0]
200        else:
201          # Text was '$ref:[foo.bar title] other stuff'.
202          ref, title = ref_with_title
203      else:
204        # Text was '$ref:foo.bar other stuff'.
205        match = self._bare_ref.match(ref_and_rest)
206        if match is None:
207          ref = ''
208          rest = ref_and_rest
209        else:
210          ref = match.group()
211          rest = ref_and_rest[match.end():]
212
213      ref_dict = self.SafeGetLink(ref, namespace=namespace, title=title)
214      formatted_text.append('<a href="%s%s">%s</a>%s' %
215          (link_prefix, ref_dict['href'], ref_dict['text'], rest))
216    return ''.join(formatted_text)
217