1#!/usr/bin/env python
2# Copyright 2012 The Chromium Authors. All rights reserved.
3# Use of this source code is governed by a BSD-style license that can be
4# found in the LICENSE file.
5
6# Format for the JSON schema file:
7# {
8#   "type_name": "DesiredCStructName",
9#   "headers": [          // Optional list of headers to be included by the .h.
10#     "path/to/header.h"
11#   ],
12#   "schema": [           // Fields of the generated structure.
13#     {
14#       "field": "my_enum_field",
15#       "type": "enum",   // Either: int, string, string16, enum, array.
16#       "default": "RED", // Optional. Cannot be used for array.
17#       "ctype": "Color"  // Only for enum, specify the C type.
18#     },
19#     {
20#       "field": "my_int_array_field",  // my_int_array_field_size will also
21#       "type": "array",                // be generated.
22#       "contents": {
23#         "type": "int"   // Either: int, string, string16, enum, array.
24#       }
25#     },
26#     ...
27#   ]
28# }
29#
30# Format for the JSON description file:
31# {
32#   "int_variables": {    // An optional list of constant int variables.
33#     "kDesiredConstantName": 45
34#   },
35#   "elements": {         // All the elements for which to create static
36#                         // initialization code in the .cc file.
37#     "my_const_variable": {
38#       "my_int_field": 10,
39#       "my_string_field": "foo bar",
40#       "my_enum_field": "BLACK",
41#       "my_int_array_field": [ 1, 2, 3, 5, 7 ],
42#     },
43#     "my_other_const_variable": {
44#       ...
45#     }
46#   }
47# }
48
49import json
50from datetime import datetime
51import os.path
52import sys
53import optparse
54import re
55_script_path = os.path.realpath(__file__)
56
57sys.path.insert(0, os.path.normpath(_script_path + "/../../json_comment_eater"))
58try:
59  import json_comment_eater
60finally:
61  sys.path.pop(0)
62
63import struct_generator
64import element_generator
65
66HEAD = """// Copyright %d The Chromium Authors. All rights reserved.
67// Use of this source code is governed by a BSD-style license that can be
68// found in the LICENSE file.
69
70// GENERATED FROM THE SCHEMA DEFINITION AND DESCRIPTION IN
71//   %s
72//   %s
73// DO NOT EDIT.
74
75"""
76
77def _GenerateHeaderGuard(h_filename):
78  """Generates the string used in #ifndef guarding the header file.
79  """
80  result = re.sub('[%s\\\\.]' % os.sep, '_', h_filename.upper())
81  return re.sub('^_*', '', result) + '_'  # Remove leading underscores.
82
83def _GenerateH(basepath, fileroot, head, namespace, schema, description):
84  """Generates the .h file containing the definition of the structure specified
85  by the schema.
86
87  Args:
88    basepath: The base directory in which files are generated.
89    fileroot: The filename and path, relative to basepath, of the file to
90        create, without an extension.
91    head: The string to output as the header of the .h file.
92    namespace: A string corresponding to the C++ namespace to use.
93    schema: A dict containing the schema. See comment at the top of this file.
94    description: A dict containing the description. See comment at the top of
95        this file.
96  """
97
98  h_filename = fileroot + '.h'
99  with open(os.path.join(basepath, h_filename), 'w') as f:
100    f.write(head)
101
102    header_guard = _GenerateHeaderGuard(h_filename)
103    f.write('#ifndef %s\n' % header_guard)
104    f.write('#define %s\n' % header_guard)
105    f.write('\n')
106
107    f.write('#include <cstddef>\n')
108    f.write('\n')
109
110    for header in schema.get('headers', []):
111      f.write('#include "%s"\n' % header)
112    f.write('\n')
113
114    if namespace:
115      f.write('namespace %s {\n' % namespace)
116      f.write('\n')
117
118    f.write(struct_generator.GenerateStruct(
119      schema['type_name'], schema['schema']))
120    f.write('\n')
121
122    for var_name, value in description.get('int_variables', []).items():
123      f.write('extern const int %s;\n' % var_name)
124    f.write('\n')
125
126    for element_name, element in description['elements'].items():
127      f.write('extern const %s %s;\n' % (schema['type_name'], element_name))
128
129    if namespace:
130      f.write('\n')
131      f.write('}  // namespace %s\n' % namespace)
132
133    f.write('\n')
134    f.write( '#endif  // %s\n' % header_guard)
135
136def _GenerateCC(basepath, fileroot, head, namespace, schema, description):
137  """Generates the .cc file containing the static initializers for the
138  of the elements specified in the description.
139
140  Args:
141    basepath: The base directory in which files are generated.
142    fileroot: The filename and path, relative to basepath, of the file to
143        create, without an extension.
144    head: The string to output as the header of the .cc file.
145    namespace: A string corresponding to the C++ namespace to use.
146    schema: A dict containing the schema. See comment at the top of this file.
147    description: A dict containing the description. See comment at the top of
148        this file.
149  """
150
151  with open(os.path.join(basepath, fileroot + '.cc'), 'w') as f:
152    f.write(head)
153
154    f.write('#include "%s"\n' % (fileroot + '.h'))
155    f.write('\n')
156
157    if namespace:
158      f.write('namespace %s {\n' % namespace)
159      f.write('\n')
160
161    f.write(element_generator.GenerateElements(schema['type_name'],
162        schema['schema'], description))
163
164    if namespace:
165      f.write('\n')
166      f.write('}  // namespace %s\n' % namespace)
167
168def _Load(filename):
169  """Loads a JSON file int a Python object and return this object.
170  """
171  # TODO(beaudoin): When moving to Python 2.7 use object_pairs_hook=OrderedDict.
172  with open(filename, 'r') as handle:
173    result = json.loads(json_comment_eater.Nom(handle.read()))
174  return result
175
176if __name__ == '__main__':
177  parser = optparse.OptionParser(
178      description='Generates an C++ array of struct from a JSON description.',
179      usage='usage: %prog [option] -s schema description')
180  parser.add_option('-b', '--destbase',
181      help='base directory of generated files.')
182  parser.add_option('-d', '--destdir',
183      help='directory to output generated files, relative to destbase.')
184  parser.add_option('-n', '--namespace',
185      help='C++ namespace for generated files. e.g search_providers.')
186  parser.add_option('-s', '--schema', help='path to the schema file, '
187      'mandatory.')
188  (opts, args) = parser.parse_args()
189
190  if not opts.schema:
191    parser.error('You must specify a --schema.')
192
193  description_filename = os.path.normpath(args[0])
194  root, ext = os.path.splitext(description_filename)
195  shortroot = os.path.split(root)[1]
196  if opts.destdir:
197    output_root = os.path.join(os.path.normpath(opts.destdir), shortroot)
198  else:
199    output_root = shortroot
200
201  if opts.destbase:
202    basepath = os.path.normpath(opts.destbase)
203  else:
204    basepath = ''
205
206  schema = _Load(opts.schema)
207  description = _Load(description_filename)
208
209  head = HEAD % (datetime.now().year, opts.schema, description_filename)
210  _GenerateH(basepath, output_root, head, opts.namespace, schema, description)
211  _GenerateCC(basepath, output_root, head, opts.namespace, schema, description)
212