Moving prepopulated search engines to a JSON file.

tools/json_to_struct/element_generator.py

Index: tools/json_to_struct/element_generator.py
diff --git a/tools/json_to_struct/element_generator.py b/tools/json_to_struct/element_generator.py
new file mode 100644
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+++ b/tools/json_to_struct/element_generator.py
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+# Copyright (c) 2012 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 json
+import struct_generator
+
+def _JSONToCString16(json_string_literal):
+  """Converts a JSON string literal to a C++ UTF-16 string literal. This is
+  done by converting \\u#### to \\x####.
+  """
+  c_string_literal = json_string_literal
+  escape_index = c_string_literal.find('\\')
+  while escape_index > 0:
+    if c_string_literal[escape_index + 1] == 'u':
+      # We close the C string literal after the 4 hex digits and reopen it right
+      # after, otherwise the Windows compiler will sometimes try to get more
+      # than 4 characters in the hex string.
+      c_string_literal = (c_string_literal[0:escape_index + 1] + 'x' +
+          c_string_literal[escape_index + 2:escape_index + 6] + '" L"' +
+          c_string_literal[escape_index + 6:])
+    escape_index = c_string_literal.find('\\', escape_index + 6)
+  return c_string_literal
+
+def _GenerateString(content, lines):
+  """Generates an UTF-8 string to be included in a static structure initializer.
+  If content is not specified, uses NULL.
+  """
+  if content is None:
+    lines.append('  NULL,')
+  else:
+    # json.dumps quotes the string and escape characters as required.
+    lines.append('  %s,' % json.dumps(content))
+
+def _GenerateString16(content, lines):
+  """Generates an UTF-16 string to be included in a static structure
+  initializer. If content is not specified, uses NULL.
+  """
+  if content is None:
+    lines.append('  NULL,')
+  else:
+    # json.dumps quotes the string and escape characters as required.
+    lines.append('  L%s,' % _JSONToCString16(json.dumps(content)))
+
+def _GenerateArray(field_info, content, lines):
+  """Generates an array to be included in a static structure initializer. If
+  content is not specified, uses NULL. The array is assigned to a temporary
+  variable which is initialized before the structure.
+  """
+  if content is None:
+    lines.append('  NULL,')
+    lines.append('  0,')  # Size of the array.
+    return
+
+  # Create a new array variable and use it in the structure initializer.
+  # This prohibits nested arrays. Add a clash detection and renaming mechanism
+  # to solve the problem.
+  var = 'array_%s' % field_info['field'];
+  lines.append('  %s,' % var)
+  lines.append('  %s,' % len(content))  # Size of the array.
+  # Generate the array content.
+  array_lines = []
+  field_info['contents']['field'] = var;
+  array_lines.append(struct_generator.GenerateField(
+                     field_info['contents']) + '[] = {')
+  for subcontent in content:
+    GenerateFieldContent(field_info['contents'], subcontent, array_lines)
+  array_lines.append('};')
+  # Prepend the generated array so it is initialized before the structure.
+  lines.reverse()
+  array_lines.reverse()
+  lines.extend(array_lines)
+  lines.reverse()
+
+def GenerateFieldContent(field_info, content, lines):
+  """Generate the content of a field to be included in the static structure
+  initializer. If the field's content is not specified, uses the default value
+  if one exists.
+  """
+  if content is None:
+    content = field_info.get('default', None)
+  type = field_info['type']
+  if type == 'int' or type == 'enum':
+    lines.append('  %s,' % content)
+  elif type == 'string':
+    _GenerateString(content, lines)
+  elif type == 'string16':
+    _GenerateString16(content, lines)
+  elif type == 'array':
+    _GenerateArray(field_info, content, lines)
+  else:
+    raise RuntimeError('Unknown field type "%s"' % type)
+
+def GenerateElement(type_name, schema, element_name, element):
+  """Generate the static structure initializer for one element.
+  """
+  lines = [];
+  lines.append('const %s %s = {' % (type_name, element_name));
+  for field_info in schema:
+    content = element.get(field_info['field'], None)
+    if (content == None and not field_info.get('optional', False)):
+      raise RuntimeError('Mandatory field "%s" omitted in element "%s".' %
+                         (field_info['field'], element_name))
+    GenerateFieldContent(field_info, content, lines)
+  lines.append('};')
+  return '\n'.join(lines)
+
+def GenerateElements(type_name, schema, description):
+  """Generate the static structure initializer for all the elements in the
+  description['elements'] dictionary, as well as for any variables in
+  description['int_variables'].
+  """
+  result = [];
+  for var_name, value in description.get('int_variables', {}).items():
+    result.append('const int %s = %s;' % (var_name, value))
+  result.append('')
+
+  for element_name, element in description.get('elements', {}).items():
+    result.append(GenerateElement(type_name, schema, element_name, element))
+    result.append('')
+  return '\n'.join(result)