tools/android/loading: Implements loading_trace_analyzer.py requests

tools/android/loading/loading_trace_analyzer.py

+#! /usr/bin/env 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.
+
+import argparse
+import json
+import re
+import sys
+
+from loading_trace import LoadingTrace
+import request_track
+
+
+def _ArgumentParser():
+  """Build a command line argument's parser.

[Benoit L, 2016/02/22 10:20:46]

s/Build/Builds/

+  """
+  parser = argparse.ArgumentParser()
+  subparsers = parser.add_subparsers(dest='subcommand', help='subcommand line')
+
+  # requests listing subcommand.
+  requests_parser = subparsers.add_parser('requests',
+      help='Lists all request from the loading trace.')
+  requests_parser.add_argument('loading_trace', type=file,
+      help='Input loading trace to see the cache usage from.')
+  requests_parser.add_argument('--output',
+      type=argparse.FileType(),
+      default=sys.stdout,
+      help='Output destination path if different from stdout.')
+  requests_parser.add_argument('--output-format', type=str, default='{url}',
+      help='Output line format (Default to "{url}")')
+  requests_parser.add_argument('--where',
+      dest='where_statement', type=str,
+      nargs=2, metavar=('FORMAT', 'REGEX'), default=[],
+      help='Where statement to filter such as: --where "{protocol}" "https?"')
+  return parser
+
+
+def _RequestsSubcommand(args):
+  """`loading_trace_analyzer.py requests` Command line tool entry point.
+
+  Example:
+    Lists all request with timing:
+      ... requests --output-format "{timing} {url}"
+
+    Lists  HTTP/HTTPS requests that have used the cache:
+      ... requests --where "{protocol} {from_disk_cache}" "https?\S* True"
+  """
+  where_format = None
+  where_statement = None
+  if args.where_statement:
+    where_format = args.where_statement[0]
+    try:
+      where_statement = re.compile(args.where_statement[1])
+    except re.error as e:
+      sys.stderr.write("Invalid where statement REGEX: {}\n{}\n".format(
+          args.where_statement[1], str(e)))
+      return 1
+
+  loading_trace = LoadingTrace.FromJsonDict(json.load(args.loading_trace))
+  for request_event in loading_trace.request_track.GetEvents():
+    request_event_json = request_event.ToJsonDict()
+
+    if where_statement != None:
+      where_in = where_format.format(**request_event_json)
+      if not where_statement.match(where_in):
+        continue
+
+    args.output.write(args.output_format.format(**request_event_json) + '\n')
+  return 0
+
+
+def main(command_line_args):
+  """Command line tool entry point.
+  """
+  args = _ArgumentParser().parse_args(command_line_args)
+  if args.subcommand == 'requests':
+    return _RequestsSubcommand(args)
+  assert False
+
+
+if __name__ == '__main__':
+  sys.exit(main(sys.argv[1:]))