tools/json_schema_compiler/json_schema.py

   1 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 # Use of this source code is governed by a BSD-style license that can be
   3 # found in the LICENSE file.
   4
   5 import copy
   6
   7 import json_parse
   8
   9
  10 def DeleteNodes(item, delete_key=None, matcher=None):
  11   """Deletes certain nodes in item, recursively. If |delete_key| is set, all
  12   dicts with |delete_key| as an attribute are deleted. If a callback is passed
  13   as |matcher|, |DeleteNodes| will delete all dicts for which matcher(dict)
  14   returns True.
  15   """
  16   assert (delete_key is not None) != (matcher is not None)
  17
  18   def ShouldDelete(thing):
  19     return json_parse.IsDict(thing) and (
  20         delete_key is not None and delete_key in thing or
  21         matcher is not None and matcher(thing))
  22
  23   if json_parse.IsDict(item):
  24     toDelete = []
  25     for key, value in item.items():
  26       if ShouldDelete(value):
  27         toDelete.append(key)
  28       else:
  29         DeleteNodes(value, delete_key, matcher)
  30     for key in toDelete:
  31       del item[key]
  32   elif type(item) == list:
  33     item[:] = [DeleteNodes(thing, delete_key, matcher)
  34         for thing in item if not ShouldDelete(thing)]
  35
  36   return item
  37
  38
  39 def Load(filename):
  40   with open(filename, 'r') as handle:
  41     schemas = json_parse.Parse(handle.read())
  42   return schemas
  43
  44
  45 # A dictionary mapping |filename| to the object resulting from loading the JSON
  46 # at |filename|.
  47 _cache = {}
  48
  49
  50 def CachedLoad(filename):
  51   """Equivalent to Load(filename), but caches results for subsequent calls"""
  52   if filename not in _cache:
  53     _cache[filename] = Load(filename)
  54   # Return a copy of the object so that any changes a caller makes won't affect
  55   # the next caller.
  56   return copy.deepcopy(_cache[filename])
  57