Add proto for TLS error assistant, refactor proto generator code.

chrome/browser/resources/protobufs/binary_proto_generator.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.
+
+"""
+ Converts a given ASCII proto into a binary resource.
+
+"""
+
+import abc
+import optparse
+import os
+import re
+import subprocess
+import sys
+import traceback
+
+class BinaryProtoGenerator:
+
+  # If the script is run in a virtualenv
+  # (https://virtualenv.pypa.io/en/stable/), then no google.protobuf library
+  # should be brought in from site-packages. Passing -S into the interpreter in
+  # a virtualenv actually destroys the ability to import standard library
+  # functions like optparse, so this script should not be wrapped if we're in a
+  # virtualenv.
+  def _IsInVirtualEnv(self):
+    # This is the way used by pip and other software to detect virtualenv.
+    return hasattr(sys, 'real_prefix')
+
+  def _ImportProtoModules(self, paths):
+    """Import the protobuf modules we need. |paths| is list of import paths"""
+    for path in paths:
+      # Put the path to our proto libraries in front, so that we don't use
+      # system protobuf.
+      sys.path.insert(1, path)
+
+    import google.protobuf.text_format as text_format
+    globals()['text_format'] = text_format
+    self.ImportProtoModule()
+
+  def _GenerateBinaryProtos(self, opts):
+    """ Read the ASCII proto and generate one or more binary protos. """
+    # Read the ASCII
+    ifile = open(opts.infile, 'r')

[Nathan Parker, 2016/12/15 00:54:30]

nit: Could this be one line,
ascii_pb_str = open(..).read()

[meacer, 2016/12/15 18:43:36]

Converted to a with block (so that the file is always closed, even when there is
a read error)

+    ascii_pb_str = ifile.read()
+    ifile.close()
+
+    # Parse it into a structured PB
+    full_pb = self.EmptyProtoInstance()
+    text_format.Merge(ascii_pb_str, full_pb)
+
+    self.ValidatePb(opts, full_pb);
+    self.ProcessPb(opts, full_pb)
+
+  @abc.abstractmethod
+  def ImportProtoModule(self):
+    """ Import the proto module to be used by the generator. """
+    pass
+
+  @abc.abstractmethod
+  def EmptyProtoInstance(self):
+    """ Returns an empty proto instance to be filled by the generator."""
+    pass
+
+  @abc.abstractmethod
+  def ValidatePb(self, opts, pb):
+    """ Validate the basic values of the protobuf.  The
+        file_type_policies_unittest.cc will also validate it by platform,
+        but this will catch errors earlier.
+    """
+    pass
+
+  @abc.abstractmethod
+  def ProcessPb(self, opts, pb):
+    """ Process the parsed prototobuf. """
+    pass
+
+  def AddCommandLineOptions(self, parser):
+    """ Allows subclasses to add any options the command line parser. """
+    pass
+
+  def AddExtraCommandLineArgsForVirtualEnvRun(self, opts, command):
+    """ Allows subclasses to add any extra command line arguments when running
+        this under a virtualenv."""
+    pass
+
+  def VerifyArgs(self, opts):
+    """ Allows subclasses to check command line parameters before running. """
+    return True
+
+  def Run(self):
+    parser = optparse.OptionParser()
+    # TODO(crbug.com/614082): Remove this once the bug is fixed.
+    parser.add_option('-w', '--wrap', action="store_true", default=False,
+                      help='Wrap this script in another python '
+                      'execution to disable site-packages.  This is a '
+                      'fix for http://crbug.com/605592')
+
+    parser.add_option('-i', '--infile',
+                      help='The ASCII proto file to read.')
+    parser.add_option('-d', '--outdir',
+                      help='Directory underwhich binary file(s) will be ' +
+                           'written')
+    parser.add_option('-o', '--outbasename',
+                      help='Basename of the binary file to write to.')
+    parser.add_option('-p', '--path', action="append",
+                      help='Repeat this as needed.  Directory(s) containing ' +
+                      'the your_proto_definition_pb2.py and ' +
+                      'google.protobuf.text_format modules')
+    self.AddCommandLineOptions(parser)
+
+    (opts, args) = parser.parse_args()
+    if opts.infile is None or opts.outdir is None or opts.outbasename is None:
+      parser.print_help()
+      return 1
+
+    if opts.wrap and not self._IsInVirtualEnv():
+      # Run this script again with different args to the interpreter to suppress
+      # the inclusion of libraries, like google.protobuf, from site-packages,
+      # which is checked before sys.path when resolving imports. We want to
+      # specifically import the libraries injected into the sys.path in
+      # ImportProtoModules().
+      command = [sys.executable, '-S', '-s', sys.argv[0]]
+      command += ['-i', opts.infile]
+      command += ['-d', opts.outdir]
+      command += ['-o', opts.outbasename]
+      for path in opts.path:
+        command += ['-p', path]
+
+      self.AddExtraCommandLineArgsForVirtualEnvRun(opts, command);
+      sys.exit(subprocess.call(command))
+
+    self._ImportProtoModules(opts.path)
+
+    if not self.VerifyArgs(opts):
+      print "Wrong arguments"
+      return 1
+
+    try:
+      self._GenerateBinaryProtos(opts)
+    except Exception as e:
+      print "ERROR: Failed to render binary version of %s:\n  %s\n%s" % (
+          opts.infile, str(e), traceback.format_exc())
+      return 1