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1#!/usr/bin/python
2#
3# Copyright 2014 The Chromium Authors. All rights reserved.
4# Use of this source code is governed by a BSD-style license that can be
5# found in the LICENSE file.
6
7"""Compute global objects.
8
9Global objects are defined by interfaces with [Global] or [PrimaryGlobal] on
10their definition: http://heycam.github.io/webidl/#Global
11
12Design document: http://www.chromium.org/developers/design-documents/idl-build
13"""
14
15import optparse
16import os
17import cPickle as pickle
18import sys
19
20from utilities import get_file_contents, idl_filename_to_interface_name, get_interface_extended_attributes_from_idl, read_file_to_list, read_pickle_files, write_pickle_file
21
22GLOBAL_EXTENDED_ATTRIBUTES = frozenset([
23    'Global',
24    'PrimaryGlobal',
25])
26
27
28def parse_options():
29    usage = 'Usage: %prog [options] [GlobalObjectsComponent.pickle]... [GlobalObjects.pickle]'
30    parser = optparse.OptionParser(usage=usage)
31    parser.add_option('--idl-files-list', help='file listing IDL files')
32    parser.add_option('--write-file-only-if-changed', type='int', help='if true, do not write an output file if it would be identical to the existing one, which avoids unnecessary rebuilds in ninja')
33
34    options, args = parser.parse_args()
35
36    if options.idl_files_list is None:
37        parser.error('Must specify a file listing IDL files using --idl-files-list.')
38    if options.write_file_only_if_changed is None:
39        parser.error('Must specify whether output files are only written if changed using --write-file-only-if-changed.')
40    options.write_file_only_if_changed = bool(options.write_file_only_if_changed)
41    if not args:
42        parser.error('Must specify an output pickle filename as argument, '
43                     'optionally preceeded by input pickle filenames.')
44
45    return options, args
46
47
48def dict_union(dicts):
49    return dict((k, v) for d in dicts for k, v in d.iteritems())
50
51
52def idl_file_to_global_names(idl_filename):
53    """Returns global names, if any, for an IDL file.
54
55    If the [Global] or [PrimaryGlobal] extended attribute is declared with an
56    identifier list argument, then those identifiers are the interface's global
57    names; otherwise, the interface has a single global name, which is the
58    interface's identifier (http://heycam.github.io/webidl/#Global).
59    """
60    interface_name = idl_filename_to_interface_name(idl_filename)
61    full_path = os.path.realpath(idl_filename)
62    idl_file_contents = get_file_contents(full_path)
63    extended_attributes = get_interface_extended_attributes_from_idl(idl_file_contents)
64
65    global_keys = GLOBAL_EXTENDED_ATTRIBUTES.intersection(
66        extended_attributes.iterkeys())
67    if not global_keys:
68        return
69    if len(global_keys) > 1:
70        raise ValueError('The [Global] and [PrimaryGlobal] extended attributes '
71                         'MUST NOT be declared on the same interface.')
72    global_key = next(iter(global_keys))
73
74    global_value = extended_attributes[global_key]
75    if global_value:
76        return global_value.strip('()').split(',')
77    return [interface_name]
78
79
80def idl_files_to_interface_name_global_names(idl_files):
81    """Yields pairs (interface_name, global_names) found in IDL files."""
82    for idl_filename in idl_files:
83        interface_name = idl_filename_to_interface_name(idl_filename)
84        global_names = idl_file_to_global_names(idl_filename)
85        if global_names:
86            yield interface_name, global_names
87
88
89################################################################################
90
91def main():
92    options, args = parse_options()
93    # args = Input1, Input2, ..., Output
94    output_global_objects_filename = args.pop()
95    interface_name_global_names = dict_union(
96        existing_interface_name_global_names
97        for existing_interface_name_global_names in read_pickle_files(args))
98
99    # Input IDL files are passed in a file, due to OS command line length
100    # limits. This is generated at GYP time, which is ok b/c files are static.
101    idl_files = read_file_to_list(options.idl_files_list)
102    interface_name_global_names.update(
103            idl_files_to_interface_name_global_names(idl_files))
104
105    write_pickle_file(output_global_objects_filename,
106                      interface_name_global_names,
107                      options.write_file_only_if_changed)
108
109
110if __name__ == '__main__':
111    sys.exit(main())
112