Implements a C++ version of JSONSchemaValidator.

chrome/common/json_schema_validator.h

+// Copyright (c) 2010 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.
+
+#ifndef CHROME_COMMON_JSON_SCHEMA_VALIDATOR_H_
+#define CHROME_COMMON_JSON_SCHEMA_VALIDATOR_H_
+
+#include <map>
+#include <string>
+#include <vector>
+
+#include "base/basictypes.h"
+
+class DictionaryValue;
+class FundamentalValue;
+class ListValue;
+class StringValue;
+class Value;
+
+class JSONSchemaValidator {

[asargent_no_longer_on_chrome, 2010/11/08 23:47:18]

It would probably be worth having a top-level comment here about the class'
general purpose, and a few brief examples of json schema and valid/invalid
input. That might make it easier to understand for a casual reader not already
familiar with our extension_api.json.

[Aaron Boodman, 2010/11/10 19:03:35]

Done.

+ public:
+  // Details about a validation error.
+  struct Error {
+    Error();
+
+    explicit Error(const std::string& message);
+
+    Error(const std::string& path, const std::string& message);
+
+    // The path to the location of the error in the JSON structure.
+    std::string path;
+
+    // An english message describing the error.
+    std::string message;
+  };
+
+  // Error messages.
+  static const char kUnknownTypeReference[];
+  static const char kInvalidChoice[];
+  static const char kInvalidEnum[];
+  static const char kObjectPropertyIsRequired[];
+  static const char kUnexpectedProperty[];
+  static const char kArrayMinItems[];
+  static const char kArrayMaxItems[];
+  static const char kArrayItemRequired[];
+  static const char kStringMinLength[];
+  static const char kStringMaxLength[];
+  static const char kStringPattern[];
+  static const char kInfinityNaNNotSupported[];
+  static const char kNumberMinimum[];
+  static const char kNumberMaximum[];
+  static const char kNumberDecimalPlaces[];
+  static const char kInvalidType[];
+
+  static std::string FormatErrorMessage(const std::string& format,

[asargent_no_longer_on_chrome, 2010/11/08 23:47:18]

nit: Document what s1 (and below, s1,s2) are used for, or give them more
descriptive names. I'm guessing they're substitutions for tokens in the error
message.

[Aaron Boodman, 2010/11/10 19:03:35]

Done.

+                                        const std::string& s1);
+  static std::string FormatErrorMessage(const std::string& format,
+                                        const std::string& s1,
+                                        const std::string& s2);
+
+  // Creates a validator for the specified schema.
+  JSONSchemaValidator(DictionaryValue* schema);
+
+  // Creates a validator for the specified schema and user-defined types. Each
+  // type must have an "id" property that can be referred to within the schema

[asargent_no_longer_on_chrome, 2010/11/08 23:47:18]

nit: In this comment, consider replacing
"Each type must have ..."
with
"Each type must be a DictionaryValue with .." 

[Aaron Boodman, 2010/11/10 19:03:35]

Done.

+  // with "ref".
+  JSONSchemaValidator(DictionaryValue* schema, ListValue* types);
+
+  // Whether the validator allows additional items for objects and lists, beyond
+  // those defined by their schema, by default.
+  //
+  // This setting defaults to false: all items in an instance list or object
+  // must be defined by the corresponding schema.
+  //
+  // This setting can be overridden on individual object and list schemas by
+  // setting the "additionalProperties" field.
+  bool default_allow_additional_properties() const {
+    return default_allow_additional_properties_;
+  }
+
+  void set_default_allow_additional_properties(bool val) {
+    default_allow_additional_properties_ = val;
+  }
+
+  // Returns any errors from the last call to to Validate().
+  const std::vector<Error>& errors() const {
+    return errors_;
+  }
+
+  // Validates a JSON value. Returns true if the instance is valid, false
+  // otherwise. If false is returned any errors are available from the errors()
+  // getter.
+  bool Validate(Value* instance);
+
+ private:
+  typedef std::map<std::string, DictionaryValue*> TypeMap;
+
+  void Validate(Value* instance, DictionaryValue* schema,
+                const std::string& path);

[asargent_no_longer_on_chrome, 2010/11/08 23:47:18]

The way that paths work is a little bit subtle, and it might be worth adding
overview documentation somewhere. 

[Aaron Boodman, 2010/11/10 19:03:35]

Done.

+
+  void ValidateChoices(Value* instance, ListValue* choices,
+                       const std::string& path);
+
+  void ValidateEnum(Value* instance, ListValue* choices,

[asargent_no_longer_on_chrome, 2010/11/08 23:47:18]

consider adding a comment here about the difference between ValidateChoices and
ValidateEnum, since they have the same method signature.

[Aaron Boodman, 2010/11/10 19:03:35]

Done.

+                    const std::string& path);
+
+  void ValidateObject(DictionaryValue* instance, DictionaryValue* schema,
+                      const std::string& path);
+
+  void ValidateArray(ListValue* instance, DictionaryValue* schema,
+                     const std::string& path);
+
+  void ValidateString(StringValue* instance, DictionaryValue* schema,
+                      const std::string& path);
+
+  void ValidateNumber(Value* instance, DictionaryValue* schema,
+                      const std::string& path);
+
+  void AddError(int error_id, const std::vector<std::string>& replacements);
+
+  bool ValidateType(Value* instance, const std::string& expected_type,
+                    const std::string& path);
+
+  bool SchemaAllowsAnyAdditionalItems(
+      DictionaryValue* schema, DictionaryValue** addition_items_schema);
+
+  // The root schema node.
+  DictionaryValue* schema_root_;
+
+  // Map of user-defined name to type.
+  TypeMap types_;
+
+  // Whether we allow additional properties on objects by default. This can be
+  // overridden by the allow_additional_properties flag on an Object schema.
+  bool default_allow_additional_properties_;
+
+  // Errors accumulated since the last call to Validate().
+  std::vector<Error> errors_;
+
+
+  DISALLOW_COPY_AND_ASSIGN(JSONSchemaValidator);
+};
+
+#endif // CHROME_COMMON_JSON_SCHEMA_VALIDATOR_H_