Extensions Docs Server: Efficient MemcacheFileSystem

chrome/common/extensions/docs/server2/subversion_file_system.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 re
 import xml.dom.minidom as xml
+from xml.parsers.expat import ExpatError
 
 import file_system
 from future import Future
 
 class SubversionFileSystem(file_system.FileSystem):
   """Class to fetch resources from src.chromium.org.
   """
-  def __init__(self, fetcher):
+  def __init__(self, fetcher, stat_fetcher):
     self._fetcher = fetcher
+    self._stat_fetcher = stat_fetcher
 
   def Read(self, paths, binary=False):
     return Future(delegate=_AsyncFetchFuture(paths, self._fetcher, binary))
 
+  def _ParseHTML(self, html):
+    """Unfortunately, the viewvc page has a stray </div> tag, so this takes care
+    of all mismatched tags.
+    """
+    try:
+      return xml.parseString(html)
+    except ExpatError as e:
+      new_html = []
+      for lineno, line in enumerate(html.split('\n')):
+        if e.lineno != lineno + 1:
+          new_html.append(line)
+      return self._ParseHTML('\n'.join(new_html))
+
+  def _CreateStatInfo(self, html):
+    dom = self._ParseHTML(html)
+    # Brace yourself, this is about to get ugly. The page returned from viewvc
+    # was not the prettiest.

[not at google - send to devlin, 2012/08/10 06:42:24]

heh. Let's hope it doesn't change; but if it does, make sure we can catch it and
update this function + redeploy.

+    tds = dom.getElementsByTagName('td')
+    a_list = []
+    found = False
+    dir_revision = None
+    for td in tds:
+      if found:
+        dir_revision = td.getElementsByTagName('a')[0].firstChild.nodeValue
+        found = False
+      a_list.extend(td.getElementsByTagName('a'))
+      if (td.firstChild is not None and
+          td.firstChild.nodeValue == 'Directory revision:'):
+        found = True
+    child_revisions = {}
+    for i in range(len(a_list)):
+      name = a_list[i].getAttribute('name')
+      if name:
+        rev = a_list[i + 1].getElementsByTagName('strong')[0]
+        if 'file' in a_list[i + 1].getAttribute('title'):
+          child_revisions[name] = rev.firstChild.nodeValue
+        else:
+          child_revisions[name + '/'] = rev.firstChild.nodeValue
+    return self.StatInfo(dir_revision, child_revisions)
+
   def Stat(self, path):
     directory = path.rsplit('/', 1)[0]
-    dir_html = self._fetcher.Fetch(directory + '/').content
-    return self.StatInfo(int(re.search('([0-9]+)', dir_html).group(0)))
+    dir_html = self._stat_fetcher.Fetch(directory + '/').content
+    return self._CreateStatInfo(dir_html)
 
 class _AsyncFetchFuture(object):
   def __init__(self, paths, fetcher, binary):
     # A list of tuples of the form (path, Future).
     self._fetches = []
     self._value = {}
     self._error = None
     self._fetches = [(path, fetcher.FetchAsync(path)) for path in paths]
     self._binary = binary
 
@@ skipping 12 matching lines @@
       elif path.endswith('/'):
         self._value[path] = self._ListDir(result.content)
       elif not self._binary:
         self._value[path] = file_system._ProcessFileData(result.content, path)
       else:
         self._value[path] = result.content
     if self._error is not None:
       raise self._error
     return self._value