blob: 1dd466181b8d8b8c5a1bcdbe15619f8c245b1d4b [file] [log] [blame]
// 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 <string>
#include "base/basictypes.h"
#include "base/callback.h"
#include "base/memory/scoped_ptr.h"
namespace base {
class Value;
} // namespace base
// Calculates and validates preference value hashes.
class PrefHashCalculator {
enum ValidationResult {
// Valid under a deprecated but as secure algorithm.
// Valid under a deprecated and less secure algorithm.
typedef base::Callback<std::string(const std::string& modern_device_id)>
// Constructs a PrefHashCalculator using |seed| and |device_id|. The same
// parameters must be used in order to successfully validate generated hashes.
// |device_id| may be empty.
PrefHashCalculator(const std::string& seed, const std::string& device_id);
// Same as the constructor above, but also specifies that
// |get_legacy_device_id_callback| should be used rather than the default to
// obtain the legacy device id if required.
const std::string& seed,
const std::string& device_id,
const GetLegacyDeviceIdCallback& get_legacy_device_id_callback);
// Calculates a hash value for the supplied preference |path| and |value|.
// |value| may be null if the preference has no value.
std::string Calculate(const std::string& path, const base::Value* value)
// Validates the provided preference hash using current and legacy hashing
// algorithms.
ValidationResult Validate(const std::string& path,
const base::Value* value,
const std::string& hash) const;
// Returns the legacy device id based off of |raw_device_id_|. This method
// lazily gets the legacy device id via |get_legacy_device_id_callback_| and
// caches the result in |legacy_device_id_instance_| for future retrievals.
std::string RetrieveLegacyDeviceId() const;
const std::string seed_;
const std::string device_id_;
// The raw device id from which the legacy device id will be derived if
// required.
const std::string raw_device_id_;
const GetLegacyDeviceIdCallback get_legacy_device_id_callback_;
// A cache for the legacy device id which is hard to compute and thus lazily
// computed when/if required (computing the original value for this instance
// is allowed in const methods).
mutable scoped_ptr<const std::string> legacy_device_id_instance_;