predictors: Track whether resources have validators, and require validation.

tools/resource_prefetch_predictor/prefetch_predictor_tool.py

 #!/usr/bin/python
 # Copyright 2016 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.
 
 """Inspection of the prefetch predictor database.
 
 On Android, the database can be extracted using:
 adb pull \
   '/data/user/0/$package_name/app_chrome/Default/Network Action Predictor'
   predictor_db
 """
 
 import argparse
 import operator
 import sqlite3
 
 
 class ResourceType(object):
   """Partially mirrors content::ResourceType."""
   STYLESHEET = 2
   SCRIPT = 3
   FONT_RESOURCE = 5
 
 
 class Entry(object):
   """Represents an entry in the predictor database."""
   HEADER = (
       'score,main_page_url,resource_type,number_of_hits,number_of_misses,'
-      'consecutive_misses,average_position,confidence,resource_url')
+      'consecutive_misses,average_position,confidence,has_validators,'
+      'always_revalidate,resource_url')
 
   def __init__(
       self, main_page_url, resource_url, resource_type, number_of_hits,
-      number_of_misses, consecutive_misses, average_position, priority):
+      number_of_misses, consecutive_misses, average_position, priority,
+      has_validators, always_revalidate):
     self.main_page_url = main_page_url
     self.resource_url = resource_url
     self.resource_type = resource_type
     self.number_of_hits = int(number_of_hits)
     self.number_of_misses = int(number_of_misses)
     self.consecutive_misses = int(consecutive_misses)
     self.average_position = int(average_position)
     self.priority = int(priority)
+    self.has_validators = bool(int(has_validators))
+    self.always_revalidate = bool(int(always_revalidate))
     self.confidence = float(number_of_hits) / (
         number_of_hits + number_of_misses)
     self.score = self._Score()
 
   def _Score(self):
     """Mirrors ResourcePrefetchPredictorTables::ResourceRow::UpdateScore."""
     multiplier = 1
     if self.resource_type in (ResourceType.STYLESHEET, ResourceType.SCRIPT,
                               ResourceType.FONT_RESOURCE):
       multiplier = 2
     return multiplier * 100 - self.average_position
 
   @classmethod
   def FromRow(cls, row):
     """Builds an entry from a database row."""
     return Entry(*row)
 
   def __str__(self):
-    return '%f,%s,%d,%d,%d,%d,%d,%f,%d\t%s' % (
+    return '%f,%s,%d,%d,%d,%d,%d,%f,%d,%d,%d\t%s' % (
         self.score, self.main_page_url, self.resource_type,
         self.number_of_hits, self.number_of_misses, self.consecutive_misses,
         self.average_position, self.confidence, self.priority,
-        self.resource_url)
+        self.has_validators, self.always_revalidate, self.resource_url)
 
 
 def FilterAndSort(entries, domain):
   """Filters and sorts the entries to be prefetched for a given domain.
 
   Uses the default thresholds defined in resource_prefetch_common.cc.
   """
   result = filter(
       lambda x: ((domain is None or x.main_page_url == domain)
                  and x.confidence > .7
                  and x.number_of_hits >= 2), entries)
   return sorted(result, key=operator.attrgetter('score'), reverse=True)
 
 
 def DatabaseStats(filename, domain):
   connection = sqlite3.connect(filename)
   c = connection.cursor()
   query = ('SELECT main_page_url, resource_url, resource_type, number_of_hits, '
-           'number_of_misses, consecutive_misses, average_position, priority '
+           'number_of_misses, consecutive_misses, average_position, priority, '
+           'has_validators, always_revalidate '
            'FROM resource_prefetch_predictor_host')
   entries = [Entry.FromRow(row) for row in c.execute(query)]
   prefetched = FilterAndSort(entries, domain)
   print Entry.HEADER
   for x in prefetched:
     print x
 
 
 def main():
   parser = argparse.ArgumentParser()
   parser.add_argument('-f', dest='database_filename', required=True,
                       help='Path to the database')
   parser.add_argument('-d', dest='domain', default=None, help='Domain')
   args = parser.parse_args()
   DatabaseStats(args.database_filename, args.domain)
 
 
 if __name__ == '__main__':
   main()