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| 1 // Copyright (c) 2011 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 #ifndef CHROME_COMMON_JSON_SCHEMA_JSON_SCHEMA_VALIDATOR_H_ | |
| 6 #define CHROME_COMMON_JSON_SCHEMA_JSON_SCHEMA_VALIDATOR_H_ | |
| 7 | |
| 8 #include <map> | |
| 9 #include <string> | |
| 10 #include <vector> | |
| 11 | |
| 12 #include "base/basictypes.h" | |
| 13 #include "base/memory/scoped_ptr.h" | |
| 14 | |
| 15 namespace base { | |
| 16 class DictionaryValue; | |
| 17 class ListValue; | |
| 18 class StringValue; | |
| 19 class Value; | |
| 20 } | |
| 21 | |
| 22 //============================================================================== | |
| 23 // This class implements a subset of JSON Schema. | |
| 24 // See: http://www.json.com/json-schema-proposal/ for more details. | |
| 25 // | |
| 26 // There is also an older JavaScript implementation of the same functionality in | |
| 27 // chrome/renderer/resources/json_schema.js. | |
| 28 // | |
| 29 // The following features of JSON Schema are not implemented: | |
| 30 // - requires | |
| 31 // - unique | |
| 32 // - disallow | |
| 33 // - union types (but replaced with 'choices') | |
| 34 // - number.maxDecimal | |
| 35 // - string.pattern | |
| 36 // | |
| 37 // The following properties are not applicable to the interface exposed by | |
| 38 // this class: | |
| 39 // - options | |
| 40 // - readonly | |
| 41 // - title | |
| 42 // - description | |
| 43 // - format | |
| 44 // - default | |
| 45 // - transient | |
| 46 // - hidden | |
| 47 // | |
| 48 // There are also these departures from the JSON Schema proposal: | |
| 49 // - null counts as 'unspecified' for optional values | |
| 50 // - added the 'choices' property, to allow specifying a list of possible types | |
| 51 // for a value | |
| 52 // - by default an "object" typed schema does not allow additional properties. | |
| 53 // if present, "additionalProperties" is to be a schema against which all | |
| 54 // additional properties will be validated. | |
| 55 //============================================================================== | |
| 56 class JSONSchemaValidator { | |
| 57 public: | |
| 58 // Details about a validation error. | |
| 59 struct Error { | |
| 60 Error(); | |
| 61 | |
| 62 explicit Error(const std::string& message); | |
| 63 | |
| 64 Error(const std::string& path, const std::string& message); | |
| 65 | |
| 66 // The path to the location of the error in the JSON structure. | |
| 67 std::string path; | |
| 68 | |
| 69 // An english message describing the error. | |
| 70 std::string message; | |
| 71 }; | |
| 72 | |
| 73 // Error messages. | |
| 74 static const char kUnknownTypeReference[]; | |
| 75 static const char kInvalidChoice[]; | |
| 76 static const char kInvalidEnum[]; | |
| 77 static const char kObjectPropertyIsRequired[]; | |
| 78 static const char kUnexpectedProperty[]; | |
| 79 static const char kArrayMinItems[]; | |
| 80 static const char kArrayMaxItems[]; | |
| 81 static const char kArrayItemRequired[]; | |
| 82 static const char kStringMinLength[]; | |
| 83 static const char kStringMaxLength[]; | |
| 84 static const char kStringPattern[]; | |
| 85 static const char kNumberMinimum[]; | |
| 86 static const char kNumberMaximum[]; | |
| 87 static const char kInvalidType[]; | |
| 88 static const char kInvalidTypeIntegerNumber[]; | |
| 89 | |
| 90 // Classifies a Value as one of the JSON schema primitive types. | |
| 91 static std::string GetJSONSchemaType(const base::Value* value); | |
| 92 | |
| 93 // Utility methods to format error messages. The first method can have one | |
| 94 // wildcard represented by '*', which is replaced with s1. The second method | |
| 95 // can have two, which are replaced by s1 and s2. | |
| 96 static std::string FormatErrorMessage(const std::string& format, | |
| 97 const std::string& s1); | |
| 98 static std::string FormatErrorMessage(const std::string& format, | |
| 99 const std::string& s1, | |
| 100 const std::string& s2); | |
| 101 | |
| 102 // Verifies if |schema| is a valid JSON v3 schema. When this validation passes | |
| 103 // then |schema| is valid JSON that can be parsed into a DictionaryValue, | |
| 104 // and that DictionaryValue can be used to build a JSONSchemaValidator. | |
| 105 // Returns the parsed DictionaryValue when |schema| validated, otherwise | |
| 106 // returns NULL. In that case, |error| contains an error description. | |
| 107 static scoped_ptr<base::DictionaryValue> IsValidSchema( | |
| 108 const std::string& schema, | |
| 109 std::string* error); | |
| 110 | |
| 111 // Creates a validator for the specified schema. | |
| 112 // | |
| 113 // NOTE: This constructor assumes that |schema| is well formed and valid. | |
| 114 // Errors will result in CHECK at runtime; this constructor should not be used | |
| 115 // with untrusted schemas. | |
| 116 explicit JSONSchemaValidator(base::DictionaryValue* schema); | |
| 117 | |
| 118 // Creates a validator for the specified schema and user-defined types. Each | |
| 119 // type must be a valid JSONSchema type description with an additional "id" | |
| 120 // field. Schema objects in |schema| can refer to these types with the "$ref" | |
| 121 // property. | |
| 122 // | |
| 123 // NOTE: This constructor assumes that |schema| and |types| are well-formed | |
| 124 // and valid. Errors will result in CHECK at runtime; this constructor should | |
| 125 // not be used with untrusted schemas. | |
| 126 JSONSchemaValidator(base::DictionaryValue* schema, base::ListValue* types); | |
| 127 | |
| 128 ~JSONSchemaValidator(); | |
| 129 | |
| 130 // Whether the validator allows additional items for objects and lists, beyond | |
| 131 // those defined by their schema, by default. | |
| 132 // | |
| 133 // This setting defaults to false: all items in an instance list or object | |
| 134 // must be defined by the corresponding schema. | |
| 135 // | |
| 136 // This setting can be overridden on individual object and list schemas by | |
| 137 // setting the "additionalProperties" field. | |
| 138 bool default_allow_additional_properties() const { | |
| 139 return default_allow_additional_properties_; | |
| 140 } | |
| 141 | |
| 142 void set_default_allow_additional_properties(bool val) { | |
| 143 default_allow_additional_properties_ = val; | |
| 144 } | |
| 145 | |
| 146 // Returns any errors from the last call to to Validate(). | |
| 147 const std::vector<Error>& errors() const { | |
| 148 return errors_; | |
| 149 } | |
| 150 | |
| 151 // Validates a JSON value. Returns true if the instance is valid, false | |
| 152 // otherwise. If false is returned any errors are available from the errors() | |
| 153 // getter. | |
| 154 bool Validate(const base::Value* instance); | |
| 155 | |
| 156 private: | |
| 157 typedef std::map<std::string, const base::DictionaryValue*> TypeMap; | |
| 158 | |
| 159 // Each of the below methods handle a subset of the validation process. The | |
| 160 // path paramater is the path to |instance| from the root of the instance tree | |
| 161 // and is used in error messages. | |
| 162 | |
| 163 // Validates any instance node against any schema node. This is called for | |
| 164 // every node in the instance tree, and it just decides which of the more | |
| 165 // detailed methods to call. | |
| 166 void Validate(const base::Value* instance, | |
| 167 const base::DictionaryValue* schema, | |
| 168 const std::string& path); | |
| 169 | |
| 170 // Validates a node against a list of possible schemas. If any one of the | |
| 171 // schemas match, the node is valid. | |
| 172 void ValidateChoices(const base::Value* instance, | |
| 173 const base::ListValue* choices, | |
| 174 const std::string& path); | |
| 175 | |
| 176 // Validates a node against a list of exact primitive values, eg 42, "foobar". | |
| 177 void ValidateEnum(const base::Value* instance, | |
| 178 const base::ListValue* choices, | |
| 179 const std::string& path); | |
| 180 | |
| 181 // Validates a JSON object against an object schema node. | |
| 182 void ValidateObject(const base::DictionaryValue* instance, | |
| 183 const base::DictionaryValue* schema, | |
| 184 const std::string& path); | |
| 185 | |
| 186 // Validates a JSON array against an array schema node. | |
| 187 void ValidateArray(const base::ListValue* instance, | |
| 188 const base::DictionaryValue* schema, | |
| 189 const std::string& path); | |
| 190 | |
| 191 // Validates a JSON array against an array schema node configured to be a | |
| 192 // tuple. In a tuple, there is one schema node for each item expected in the | |
| 193 // array. | |
| 194 void ValidateTuple(const base::ListValue* instance, | |
| 195 const base::DictionaryValue* schema, | |
| 196 const std::string& path); | |
| 197 | |
| 198 // Validate a JSON string against a string schema node. | |
| 199 void ValidateString(const base::Value* instance, | |
| 200 const base::DictionaryValue* schema, | |
| 201 const std::string& path); | |
| 202 | |
| 203 // Validate a JSON number against a number schema node. | |
| 204 void ValidateNumber(const base::Value* instance, | |
| 205 const base::DictionaryValue* schema, | |
| 206 const std::string& path); | |
| 207 | |
| 208 // Validates that the JSON node |instance| has |expected_type|. | |
| 209 bool ValidateType(const base::Value* instance, | |
| 210 const std::string& expected_type, | |
| 211 const std::string& path); | |
| 212 | |
| 213 // Returns true if |schema| will allow additional items of any type. | |
| 214 bool SchemaAllowsAnyAdditionalItems( | |
| 215 const base::DictionaryValue* schema, | |
| 216 const base::DictionaryValue** addition_items_schema); | |
| 217 | |
| 218 // The root schema node. | |
| 219 base::DictionaryValue* schema_root_; | |
| 220 | |
| 221 // Map of user-defined name to type. | |
| 222 TypeMap types_; | |
| 223 | |
| 224 // Whether we allow additional properties on objects by default. This can be | |
| 225 // overridden by the allow_additional_properties flag on an Object schema. | |
| 226 bool default_allow_additional_properties_; | |
| 227 | |
| 228 // Errors accumulated since the last call to Validate(). | |
| 229 std::vector<Error> errors_; | |
| 230 | |
| 231 | |
| 232 DISALLOW_COPY_AND_ASSIGN(JSONSchemaValidator); | |
| 233 }; | |
| 234 | |
| 235 #endif // CHROME_COMMON_JSON_SCHEMA_JSON_SCHEMA_VALIDATOR_H_ | |
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