root/components/json_schema/json_schema_validator.cc

/* [<][>][^][v][top][bottom][index][help] */

DEFINITIONS

This source file includes following definitions.
  1. GetNumberValue
  2. IsValidType
  3. CompareToString
  4. ExtractNameFromDictionary
  5. IsValidSchema
  6. message
  7. GetJSONSchemaType
  8. FormatErrorMessage
  9. FormatErrorMessage
  10. IsValidSchema
  11. IsValidSchema
  12. default_allow_additional_properties_
  13. default_allow_additional_properties_
  14. Validate
  15. Validate
  16. ValidateChoices
  17. ValidateEnum
  18. ValidateObject
  19. ValidateArray
  20. ValidateTuple
  21. ValidateString
  22. ValidateNumber
  23. ValidateType
  24. SchemaAllowsAnyAdditionalItems

// Copyright 2013 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.

#include "components/json_schema/json_schema_validator.h"

#include <algorithm>
#include <cfloat>
#include <cmath>
#include <vector>

#include "base/json/json_reader.h"
#include "base/logging.h"
#include "base/memory/scoped_vector.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_util.h"
#include "base/strings/stringprintf.h"
#include "base/values.h"
#include "components/json_schema/json_schema_constants.h"
#include "third_party/re2/re2/re2.h"

namespace schema = json_schema_constants;

namespace {

double GetNumberValue(const base::Value* value) {
  double result = 0;
  CHECK(value->GetAsDouble(&result))
      << "Unexpected value type: " << value->GetType();
  return result;
}

bool IsValidType(const std::string& type) {
  static const char* kValidTypes[] = {
    schema::kAny,
    schema::kArray,
    schema::kBoolean,
    schema::kInteger,
    schema::kNull,
    schema::kNumber,
    schema::kObject,
    schema::kString,
  };
  const char** end = kValidTypes + arraysize(kValidTypes);
  return std::find(kValidTypes, end, type) != end;
}

// Maps a schema attribute name to its expected type.
struct ExpectedType {
  const char* key;
  base::Value::Type type;
};

// Helper for std::lower_bound.
bool CompareToString(const ExpectedType& entry, const std::string& key) {
  return entry.key < key;
}

// If |value| is a dictionary, returns the "name" attribute of |value| or NULL
// if |value| does not contain a "name" attribute. Otherwise, returns |value|.
const base::Value* ExtractNameFromDictionary(const base::Value* value) {
  const base::DictionaryValue* value_dict = NULL;
  const base::Value* name_value = NULL;
  if (value->GetAsDictionary(&value_dict)) {
    value_dict->Get("name", &name_value);
    return name_value;
  }
  return value;
}

bool IsValidSchema(const base::DictionaryValue* dict,
                   int options,
                   std::string* error) {
  // This array must be sorted, so that std::lower_bound can perform a
  // binary search.
  static const ExpectedType kExpectedTypes[] = {
    // Note: kRef == "$ref", kSchema == "$schema"
    { schema::kRef,                     base::Value::TYPE_STRING      },
    { schema::kSchema,                  base::Value::TYPE_STRING      },

    { schema::kAdditionalProperties,    base::Value::TYPE_DICTIONARY  },
    { schema::kChoices,                 base::Value::TYPE_LIST        },
    { schema::kDescription,             base::Value::TYPE_STRING      },
    { schema::kEnum,                    base::Value::TYPE_LIST        },
    { schema::kId,                      base::Value::TYPE_STRING      },
    { schema::kMaxItems,                base::Value::TYPE_INTEGER     },
    { schema::kMaxLength,               base::Value::TYPE_INTEGER     },
    { schema::kMaximum,                 base::Value::TYPE_DOUBLE      },
    { schema::kMinItems,                base::Value::TYPE_INTEGER     },
    { schema::kMinLength,               base::Value::TYPE_INTEGER     },
    { schema::kMinimum,                 base::Value::TYPE_DOUBLE      },
    { schema::kOptional,                base::Value::TYPE_BOOLEAN     },
    { schema::kPattern,                 base::Value::TYPE_STRING      },
    { schema::kPatternProperties,       base::Value::TYPE_DICTIONARY  },
    { schema::kProperties,              base::Value::TYPE_DICTIONARY  },
    { schema::kTitle,                   base::Value::TYPE_STRING      },
  };

  bool has_type_or_ref = false;
  const base::ListValue* list_value = NULL;
  const base::DictionaryValue* dictionary_value = NULL;
  std::string string_value;

  for (base::DictionaryValue::Iterator it(*dict); !it.IsAtEnd(); it.Advance()) {
    // Validate the "type" attribute, which may be a string or a list.
    if (it.key() == schema::kType) {
      switch (it.value().GetType()) {
        case base::Value::TYPE_STRING:
          it.value().GetAsString(&string_value);
          if (!IsValidType(string_value)) {
            *error = "Invalid value for type attribute";
            return false;
          }
          break;
        case base::Value::TYPE_LIST:
          it.value().GetAsList(&list_value);
          for (size_t i = 0; i < list_value->GetSize(); ++i) {
            if (!list_value->GetString(i, &string_value) ||
                !IsValidType(string_value)) {
              *error = "Invalid value for type attribute";
              return false;
            }
          }
          break;
        default:
          *error = "Invalid value for type attribute";
          return false;
      }
      has_type_or_ref = true;
      continue;
    }

    // Validate the "items" attribute, which is a schema or a list of schemas.
    if (it.key() == schema::kItems) {
      if (it.value().GetAsDictionary(&dictionary_value)) {
        if (!IsValidSchema(dictionary_value, options, error)) {
          DCHECK(!error->empty());
          return false;
        }
      } else if (it.value().GetAsList(&list_value)) {
        for (size_t i = 0; i < list_value->GetSize(); ++i) {
          if (!list_value->GetDictionary(i, &dictionary_value)) {
            *error = base::StringPrintf(
                "Invalid entry in items attribute at index %d",
                static_cast<int>(i));
            return false;
          }
          if (!IsValidSchema(dictionary_value, options, error)) {
            DCHECK(!error->empty());
            return false;
          }
        }
      } else {
        *error = "Invalid value for items attribute";
        return false;
      }
      continue;
    }

    // All the other attributes have a single valid type.
    const ExpectedType* end = kExpectedTypes + arraysize(kExpectedTypes);
    const ExpectedType* entry = std::lower_bound(
        kExpectedTypes, end, it.key(), CompareToString);
    if (entry == end || entry->key != it.key()) {
      if (options & JSONSchemaValidator::OPTIONS_IGNORE_UNKNOWN_ATTRIBUTES)
        continue;
      *error = base::StringPrintf("Invalid attribute %s", it.key().c_str());
      return false;
    }

    // Integer can be converted to double.
    if (!(it.value().IsType(entry->type) ||
          (it.value().IsType(base::Value::TYPE_INTEGER) &&
           entry->type == base::Value::TYPE_DOUBLE))) {
      *error = base::StringPrintf("Invalid value for %s attribute",
                                  it.key().c_str());
      return false;
    }

    // base::Value::TYPE_INTEGER attributes must be >= 0.
    // This applies to "minItems", "maxItems", "minLength" and "maxLength".
    if (it.value().IsType(base::Value::TYPE_INTEGER)) {
      int integer_value;
      it.value().GetAsInteger(&integer_value);
      if (integer_value < 0) {
        *error = base::StringPrintf("Value of %s must be >= 0, got %d",
                                    it.key().c_str(), integer_value);
        return false;
      }
    }

    // Validate the "properties" attribute. Each entry maps a key to a schema.
    if (it.key() == schema::kProperties) {
      it.value().GetAsDictionary(&dictionary_value);
      for (base::DictionaryValue::Iterator iter(*dictionary_value);
           !iter.IsAtEnd(); iter.Advance()) {
        if (!iter.value().GetAsDictionary(&dictionary_value)) {
          *error = "properties must be a dictionary";
          return false;
        }
        if (!IsValidSchema(dictionary_value, options, error)) {
          DCHECK(!error->empty());
          return false;
        }
      }
    }

    // Validate the "patternProperties" attribute. Each entry maps a regular
    // expression to a schema. The validity of the regular expression expression
    // won't be checked here for performance reasons. Instead, invalid regular
    // expressions will be caught as validation errors in Validate().
    if (it.key() == schema::kPatternProperties) {
      it.value().GetAsDictionary(&dictionary_value);
      for (base::DictionaryValue::Iterator iter(*dictionary_value);
           !iter.IsAtEnd(); iter.Advance()) {
        if (!iter.value().GetAsDictionary(&dictionary_value)) {
          *error = "patternProperties must be a dictionary";
          return false;
        }
        if (!IsValidSchema(dictionary_value, options, error)) {
          DCHECK(!error->empty());
          return false;
        }
      }
    }

    // Validate "additionalProperties" attribute, which is a schema.
    if (it.key() == schema::kAdditionalProperties) {
      it.value().GetAsDictionary(&dictionary_value);
      if (!IsValidSchema(dictionary_value, options, error)) {
        DCHECK(!error->empty());
        return false;
      }
    }

    // Validate the values contained in an "enum" attribute.
    if (it.key() == schema::kEnum) {
      it.value().GetAsList(&list_value);
      for (size_t i = 0; i < list_value->GetSize(); ++i) {
        const base::Value* value = NULL;
        list_value->Get(i, &value);
        // Sometimes the enum declaration is a dictionary with the enum value
        // under "name".
        value = ExtractNameFromDictionary(value);
        if (!value) {
          *error = "Invalid value in enum attribute";
          return false;
        }
        switch (value->GetType()) {
          case base::Value::TYPE_NULL:
          case base::Value::TYPE_BOOLEAN:
          case base::Value::TYPE_INTEGER:
          case base::Value::TYPE_DOUBLE:
          case base::Value::TYPE_STRING:
            break;
          default:
            *error = "Invalid value in enum attribute";
            return false;
        }
      }
    }

    // Validate the schemas contained in a "choices" attribute.
    if (it.key() == schema::kChoices) {
      it.value().GetAsList(&list_value);
      for (size_t i = 0; i < list_value->GetSize(); ++i) {
        if (!list_value->GetDictionary(i, &dictionary_value)) {
          *error = "Invalid choices attribute";
          return false;
        }
        if (!IsValidSchema(dictionary_value, options, error)) {
          DCHECK(!error->empty());
          return false;
        }
      }
    }

    if (it.key() == schema::kRef)
      has_type_or_ref = true;
  }

  if (!has_type_or_ref) {
    *error = "Schema must have a type or a $ref attribute";
    return false;
  }

  return true;
}

}  // namespace


JSONSchemaValidator::Error::Error() {
}

JSONSchemaValidator::Error::Error(const std::string& message)
    : path(message) {
}

JSONSchemaValidator::Error::Error(const std::string& path,
                                  const std::string& message)
    : path(path), message(message) {
}


const char JSONSchemaValidator::kUnknownTypeReference[] =
    "Unknown schema reference: *.";
const char JSONSchemaValidator::kInvalidChoice[] =
    "Value does not match any valid type choices.";
const char JSONSchemaValidator::kInvalidEnum[] =
    "Value does not match any valid enum choices.";
const char JSONSchemaValidator::kObjectPropertyIsRequired[] =
    "Property is required.";
const char JSONSchemaValidator::kUnexpectedProperty[] =
    "Unexpected property.";
const char JSONSchemaValidator::kArrayMinItems[] =
    "Array must have at least * items.";
const char JSONSchemaValidator::kArrayMaxItems[] =
    "Array must not have more than * items.";
const char JSONSchemaValidator::kArrayItemRequired[] =
    "Item is required.";
const char JSONSchemaValidator::kStringMinLength[] =
    "String must be at least * characters long.";
const char JSONSchemaValidator::kStringMaxLength[] =
    "String must not be more than * characters long.";
const char JSONSchemaValidator::kStringPattern[] =
    "String must match the pattern: *.";
const char JSONSchemaValidator::kNumberMinimum[] =
    "Value must not be less than *.";
const char JSONSchemaValidator::kNumberMaximum[] =
    "Value must not be greater than *.";
const char JSONSchemaValidator::kInvalidType[] =
    "Expected '*' but got '*'.";
const char JSONSchemaValidator::kInvalidTypeIntegerNumber[] =
    "Expected 'integer' but got 'number', consider using Math.round().";
const char JSONSchemaValidator::kInvalidRegex[] =
    "Regular expression /*/ is invalid: *";


// static
std::string JSONSchemaValidator::GetJSONSchemaType(const base::Value* value) {
  switch (value->GetType()) {
    case base::Value::TYPE_NULL:
      return schema::kNull;
    case base::Value::TYPE_BOOLEAN:
      return schema::kBoolean;
    case base::Value::TYPE_INTEGER:
      return schema::kInteger;
    case base::Value::TYPE_DOUBLE: {
      double double_value = 0;
      value->GetAsDouble(&double_value);
      if (std::abs(double_value) <= std::pow(2.0, DBL_MANT_DIG) &&
          double_value == floor(double_value)) {
        return schema::kInteger;
      } else {
        return schema::kNumber;
      }
    }
    case base::Value::TYPE_STRING:
      return schema::kString;
    case base::Value::TYPE_DICTIONARY:
      return schema::kObject;
    case base::Value::TYPE_LIST:
      return schema::kArray;
    default:
      NOTREACHED() << "Unexpected value type: " << value->GetType();
      return std::string();
  }
}

// static
std::string JSONSchemaValidator::FormatErrorMessage(const std::string& format,
                                                    const std::string& s1) {
  std::string ret_val = format;
  ReplaceFirstSubstringAfterOffset(&ret_val, 0, "*", s1);
  return ret_val;
}

// static
std::string JSONSchemaValidator::FormatErrorMessage(const std::string& format,
                                                    const std::string& s1,
                                                    const std::string& s2) {
  std::string ret_val = format;
  ReplaceFirstSubstringAfterOffset(&ret_val, 0, "*", s1);
  ReplaceFirstSubstringAfterOffset(&ret_val, 0, "*", s2);
  return ret_val;
}

// static
scoped_ptr<base::DictionaryValue> JSONSchemaValidator::IsValidSchema(
    const std::string& schema,
    std::string* error) {
  return JSONSchemaValidator::IsValidSchema(schema, 0, error);
}

// static
scoped_ptr<base::DictionaryValue> JSONSchemaValidator::IsValidSchema(
    const std::string& schema,
    int validator_options,
    std::string* error) {
  base::JSONParserOptions json_options = base::JSON_PARSE_RFC;
  scoped_ptr<base::Value> json(
      base::JSONReader::ReadAndReturnError(schema, json_options, NULL, error));
  if (!json)
    return scoped_ptr<base::DictionaryValue>();
  base::DictionaryValue* dict = NULL;
  if (!json->GetAsDictionary(&dict)) {
    *error = "Schema must be a JSON object";
    return scoped_ptr<base::DictionaryValue>();
  }
  if (!::IsValidSchema(dict, validator_options, error))
    return scoped_ptr<base::DictionaryValue>();
  ignore_result(json.release());
  return make_scoped_ptr(dict);
}

JSONSchemaValidator::JSONSchemaValidator(base::DictionaryValue* schema)
    : schema_root_(schema), default_allow_additional_properties_(false) {
}

JSONSchemaValidator::JSONSchemaValidator(base::DictionaryValue* schema,
                                         base::ListValue* types)
    : schema_root_(schema), default_allow_additional_properties_(false) {
  if (!types)
    return;

  for (size_t i = 0; i < types->GetSize(); ++i) {
    base::DictionaryValue* type = NULL;
    CHECK(types->GetDictionary(i, &type));

    std::string id;
    CHECK(type->GetString(schema::kId, &id));

    CHECK(types_.find(id) == types_.end());
    types_[id] = type;
  }
}

JSONSchemaValidator::~JSONSchemaValidator() {}

bool JSONSchemaValidator::Validate(const base::Value* instance) {
  errors_.clear();
  Validate(instance, schema_root_, std::string());
  return errors_.empty();
}

void JSONSchemaValidator::Validate(const base::Value* instance,
                                   const base::DictionaryValue* schema,
                                   const std::string& path) {
  // If this schema defines itself as reference type, save it in this.types.
  std::string id;
  if (schema->GetString(schema::kId, &id)) {
    TypeMap::iterator iter = types_.find(id);
    if (iter == types_.end())
      types_[id] = schema;
    else
      DCHECK(iter->second == schema);
  }

  // If the schema has a $ref property, the instance must validate against
  // that schema. It must be present in types_ to be referenced.
  std::string ref;
  if (schema->GetString(schema::kRef, &ref)) {
    TypeMap::iterator type = types_.find(ref);
    if (type == types_.end()) {
      errors_.push_back(
          Error(path, FormatErrorMessage(kUnknownTypeReference, ref)));
    } else {
      Validate(instance, type->second, path);
    }
    return;
  }

  // If the schema has a choices property, the instance must validate against at
  // least one of the items in that array.
  const base::ListValue* choices = NULL;
  if (schema->GetList(schema::kChoices, &choices)) {
    ValidateChoices(instance, choices, path);
    return;
  }

  // If the schema has an enum property, the instance must be one of those
  // values.
  const base::ListValue* enumeration = NULL;
  if (schema->GetList(schema::kEnum, &enumeration)) {
    ValidateEnum(instance, enumeration, path);
    return;
  }

  std::string type;
  schema->GetString(schema::kType, &type);
  CHECK(!type.empty());
  if (type != schema::kAny) {
    if (!ValidateType(instance, type, path))
      return;

    // These casts are safe because of checks in ValidateType().
    if (type == schema::kObject) {
      ValidateObject(static_cast<const base::DictionaryValue*>(instance),
                     schema,
                     path);
    } else if (type == schema::kArray) {
      ValidateArray(static_cast<const base::ListValue*>(instance),
                    schema, path);
    } else if (type == schema::kString) {
      // Intentionally NOT downcasting to StringValue*. TYPE_STRING only implies
      // GetAsString() can safely be carried out, not that it's a StringValue.
      ValidateString(instance, schema, path);
    } else if (type == schema::kNumber || type == schema::kInteger) {
      ValidateNumber(instance, schema, path);
    } else if (type != schema::kBoolean && type != schema::kNull) {
      NOTREACHED() << "Unexpected type: " << type;
    }
  }
}

void JSONSchemaValidator::ValidateChoices(const base::Value* instance,
                                          const base::ListValue* choices,
                                          const std::string& path) {
  size_t original_num_errors = errors_.size();

  for (size_t i = 0; i < choices->GetSize(); ++i) {
    const base::DictionaryValue* choice = NULL;
    CHECK(choices->GetDictionary(i, &choice));

    Validate(instance, choice, path);
    if (errors_.size() == original_num_errors)
      return;

    // We discard the error from each choice. We only want to know if any of the
    // validations succeeded.
    errors_.resize(original_num_errors);
  }

  // Now add a generic error that no choices matched.
  errors_.push_back(Error(path, kInvalidChoice));
  return;
}

void JSONSchemaValidator::ValidateEnum(const base::Value* instance,
                                       const base::ListValue* choices,
                                       const std::string& path) {
  for (size_t i = 0; i < choices->GetSize(); ++i) {
    const base::Value* choice = NULL;
    CHECK(choices->Get(i, &choice));
    // Sometimes the enum declaration is a dictionary with the enum value under
    // "name".
    choice = ExtractNameFromDictionary(choice);
    if (!choice) {
      NOTREACHED();
    }
    switch (choice->GetType()) {
      case base::Value::TYPE_NULL:
      case base::Value::TYPE_BOOLEAN:
      case base::Value::TYPE_STRING:
        if (instance->Equals(choice))
          return;
        break;

      case base::Value::TYPE_INTEGER:
      case base::Value::TYPE_DOUBLE:
        if (instance->IsType(base::Value::TYPE_INTEGER) ||
            instance->IsType(base::Value::TYPE_DOUBLE)) {
          if (GetNumberValue(choice) == GetNumberValue(instance))
            return;
        }
        break;

      default:
       NOTREACHED() << "Unexpected type in enum: " << choice->GetType();
    }
  }

  errors_.push_back(Error(path, kInvalidEnum));
}

void JSONSchemaValidator::ValidateObject(const base::DictionaryValue* instance,
                                         const base::DictionaryValue* schema,
                                         const std::string& path) {
  const base::DictionaryValue* properties = NULL;
  if (schema->GetDictionary(schema::kProperties, &properties)) {
    for (base::DictionaryValue::Iterator it(*properties); !it.IsAtEnd();
         it.Advance()) {
      std::string prop_path = path.empty() ? it.key() : (path + "." + it.key());
      const base::DictionaryValue* prop_schema = NULL;
      CHECK(it.value().GetAsDictionary(&prop_schema));

      const base::Value* prop_value = NULL;
      if (instance->Get(it.key(), &prop_value)) {
        Validate(prop_value, prop_schema, prop_path);
      } else {
        // Properties are required unless there is an optional field set to
        // 'true'.
        bool is_optional = false;
        prop_schema->GetBoolean(schema::kOptional, &is_optional);
        if (!is_optional) {
          errors_.push_back(Error(prop_path, kObjectPropertyIsRequired));
        }
      }
    }
  }

  const base::DictionaryValue* additional_properties_schema = NULL;
  bool allow_any_additional_properties =
      SchemaAllowsAnyAdditionalItems(schema, &additional_properties_schema);

  const base::DictionaryValue* pattern_properties = NULL;
  ScopedVector<re2::RE2> pattern_properties_pattern;
  std::vector<const base::DictionaryValue*> pattern_properties_schema;

  if (schema->GetDictionary(schema::kPatternProperties, &pattern_properties)) {
    for (base::DictionaryValue::Iterator it(*pattern_properties); !it.IsAtEnd();
         it.Advance()) {
      re2::RE2* prop_pattern = new re2::RE2(it.key());
      if (!prop_pattern->ok()) {
        LOG(WARNING) << "Regular expression /" << it.key()
                     << "/ is invalid: " << prop_pattern->error() << ".";
        errors_.push_back(
            Error(path,
                  FormatErrorMessage(
                      kInvalidRegex, it.key(), prop_pattern->error())));
        continue;
      }
      const base::DictionaryValue* prop_schema = NULL;
      CHECK(it.value().GetAsDictionary(&prop_schema));
      pattern_properties_pattern.push_back(prop_pattern);
      pattern_properties_schema.push_back(prop_schema);
    }
  }

  // Validate pattern properties and additional properties.
  for (base::DictionaryValue::Iterator it(*instance); !it.IsAtEnd();
       it.Advance()) {
    std::string prop_path = path.empty() ? it.key() : path + "." + it.key();

    bool found_matching_pattern = false;
    for (size_t index = 0; index < pattern_properties_pattern.size(); ++index) {
      if (re2::RE2::PartialMatch(it.key(),
                                 *pattern_properties_pattern[index])) {
        found_matching_pattern = true;
        Validate(&it.value(), pattern_properties_schema[index], prop_path);
        break;
      }
    }

    if (found_matching_pattern || allow_any_additional_properties ||
        (properties && properties->HasKey(it.key())))
      continue;

    if (!additional_properties_schema) {
      errors_.push_back(Error(prop_path, kUnexpectedProperty));
    } else {
      Validate(&it.value(), additional_properties_schema, prop_path);
    }
  }
}

void JSONSchemaValidator::ValidateArray(const base::ListValue* instance,
                                        const base::DictionaryValue* schema,
                                        const std::string& path) {
  const base::DictionaryValue* single_type = NULL;
  size_t instance_size = instance->GetSize();
  if (schema->GetDictionary(schema::kItems, &single_type)) {
    int min_items = 0;
    if (schema->GetInteger(schema::kMinItems, &min_items)) {
      CHECK(min_items >= 0);
      if (instance_size < static_cast<size_t>(min_items)) {
        errors_.push_back(Error(path, FormatErrorMessage(
            kArrayMinItems, base::IntToString(min_items))));
      }
    }

    int max_items = 0;
    if (schema->GetInteger(schema::kMaxItems, &max_items)) {
      CHECK(max_items >= 0);
      if (instance_size > static_cast<size_t>(max_items)) {
        errors_.push_back(Error(path, FormatErrorMessage(
            kArrayMaxItems, base::IntToString(max_items))));
      }
    }

    // If the items property is a single schema, each item in the array must
    // validate against that schema.
    for (size_t i = 0; i < instance_size; ++i) {
      const base::Value* item = NULL;
      CHECK(instance->Get(i, &item));
      std::string i_str = base::Uint64ToString(i);
      std::string item_path = path.empty() ? i_str : (path + "." + i_str);
      Validate(item, single_type, item_path);
    }

    return;
  }

  // Otherwise, the list must be a tuple type, where each item in the list has a
  // particular schema.
  ValidateTuple(instance, schema, path);
}

void JSONSchemaValidator::ValidateTuple(const base::ListValue* instance,
                                        const base::DictionaryValue* schema,
                                        const std::string& path) {
  const base::ListValue* tuple_type = NULL;
  schema->GetList(schema::kItems, &tuple_type);
  size_t tuple_size = tuple_type ? tuple_type->GetSize() : 0;
  if (tuple_type) {
    for (size_t i = 0; i < tuple_size; ++i) {
      std::string i_str = base::Uint64ToString(i);
      std::string item_path = path.empty() ? i_str : (path + "." + i_str);
      const base::DictionaryValue* item_schema = NULL;
      CHECK(tuple_type->GetDictionary(i, &item_schema));
      const base::Value* item_value = NULL;
      instance->Get(i, &item_value);
      if (item_value && item_value->GetType() != base::Value::TYPE_NULL) {
        Validate(item_value, item_schema, item_path);
      } else {
        bool is_optional = false;
        item_schema->GetBoolean(schema::kOptional, &is_optional);
        if (!is_optional) {
          errors_.push_back(Error(item_path, kArrayItemRequired));
          return;
        }
      }
    }
  }

  const base::DictionaryValue* additional_properties_schema = NULL;
  if (SchemaAllowsAnyAdditionalItems(schema, &additional_properties_schema))
    return;

  size_t instance_size = instance->GetSize();
  if (additional_properties_schema) {
    // Any additional properties must validate against the additionalProperties
    // schema.
    for (size_t i = tuple_size; i < instance_size; ++i) {
      std::string i_str = base::Uint64ToString(i);
      std::string item_path = path.empty() ? i_str : (path + "." + i_str);
      const base::Value* item_value = NULL;
      CHECK(instance->Get(i, &item_value));
      Validate(item_value, additional_properties_schema, item_path);
    }
  } else if (instance_size > tuple_size) {
    errors_.push_back(Error(path, FormatErrorMessage(
        kArrayMaxItems, base::Uint64ToString(tuple_size))));
  }
}

void JSONSchemaValidator::ValidateString(const base::Value* instance,
                                         const base::DictionaryValue* schema,
                                         const std::string& path) {
  std::string value;
  CHECK(instance->GetAsString(&value));

  int min_length = 0;
  if (schema->GetInteger(schema::kMinLength, &min_length)) {
    CHECK(min_length >= 0);
    if (value.size() < static_cast<size_t>(min_length)) {
      errors_.push_back(Error(path, FormatErrorMessage(
          kStringMinLength, base::IntToString(min_length))));
    }
  }

  int max_length = 0;
  if (schema->GetInteger(schema::kMaxLength, &max_length)) {
    CHECK(max_length >= 0);
    if (value.size() > static_cast<size_t>(max_length)) {
      errors_.push_back(Error(path, FormatErrorMessage(
          kStringMaxLength, base::IntToString(max_length))));
    }
  }

  std::string pattern;
  if (schema->GetString(schema::kPattern, &pattern)) {
    re2::RE2 compiled_regex(pattern);
    if (!compiled_regex.ok()) {
      LOG(WARNING) << "Regular expression /" << pattern
                   << "/ is invalid: " << compiled_regex.error() << ".";
      errors_.push_back(Error(
          path,
          FormatErrorMessage(kInvalidRegex, pattern, compiled_regex.error())));
    } else if (!re2::RE2::PartialMatch(value, compiled_regex)) {
      errors_.push_back(
          Error(path, FormatErrorMessage(kStringPattern, pattern)));
    }
  }
}

void JSONSchemaValidator::ValidateNumber(const base::Value* instance,
                                         const base::DictionaryValue* schema,
                                         const std::string& path) {
  double value = GetNumberValue(instance);

  // TODO(aa): It would be good to test that the double is not infinity or nan,
  // but isnan and isinf aren't defined on Windows.

  double minimum = 0;
  if (schema->GetDouble(schema::kMinimum, &minimum)) {
    if (value < minimum)
      errors_.push_back(Error(path, FormatErrorMessage(
          kNumberMinimum, base::DoubleToString(minimum))));
  }

  double maximum = 0;
  if (schema->GetDouble(schema::kMaximum, &maximum)) {
    if (value > maximum)
      errors_.push_back(Error(path, FormatErrorMessage(
          kNumberMaximum, base::DoubleToString(maximum))));
  }
}

bool JSONSchemaValidator::ValidateType(const base::Value* instance,
                                       const std::string& expected_type,
                                       const std::string& path) {
  std::string actual_type = GetJSONSchemaType(instance);
  if (expected_type == actual_type ||
      (expected_type == schema::kNumber && actual_type == schema::kInteger)) {
    return true;
  } else if (expected_type == schema::kInteger &&
             actual_type == schema::kNumber) {
    errors_.push_back(Error(path, kInvalidTypeIntegerNumber));
    return false;
  } else {
    errors_.push_back(Error(path, FormatErrorMessage(
        kInvalidType, expected_type, actual_type)));
    return false;
  }
}

bool JSONSchemaValidator::SchemaAllowsAnyAdditionalItems(
    const base::DictionaryValue* schema,
    const base::DictionaryValue** additional_properties_schema) {
  // If the validator allows additional properties globally, and this schema
  // doesn't override, then we can exit early.
  schema->GetDictionary(schema::kAdditionalProperties,
                        additional_properties_schema);

  if (*additional_properties_schema) {
    std::string additional_properties_type(schema::kAny);
    CHECK((*additional_properties_schema)->GetString(
        schema::kType, &additional_properties_type));
    return additional_properties_type == schema::kAny;
  } else {
    return default_allow_additional_properties_;
  }
}

/* [<][>][^][v][top][bottom][index][help] */