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// Copyright 2014 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/compiler_specific.h"
#include "base/gtest_prod_util.h"
#include "base/macros.h"
#include "base/time/time.h"
#include "build/build_config.h"
class PrefService;
class PrefRegistrySimple;
namespace variations {
class VariationsSeed;
namespace variations {
// VariationsSeedStore is a helper class for reading and writing the variations
// seed from Local State.
class VariationsSeedStore {
explicit VariationsSeedStore(PrefService* local_state);
virtual ~VariationsSeedStore();
// Loads the variations seed data from local state into |seed|. If there is a
// problem with loading, the pref value is cleared and false is returned. If
// successful, |seed| will contain the loaded data and true is returned.
bool LoadSeed(variations::VariationsSeed* seed);
// Stores the given seed |data| (serialized protobuf) to local state, along
// with a base64-encoded digital signature for seed and the date when it was
// fetched. If |is_gzip_compressed| is true, treats |data| as being gzip
// compressed and decompresses it before any other processing.
// If |is_delta_compressed| is true, treats |data| as being delta
// compressed and attempts to decode it first using the store's seed data.
// The actual seed data will be base64 encoded for storage. If the string
// is invalid, the existing prefs are untouched and false is returned.
// Additionally, stores the |country_code| that was received with the seed in
// a separate pref. On success and if |parsed_seed| is not NULL, |parsed_seed|
// will be filled with the de-serialized decoded protobuf.
bool StoreSeedData(const std::string& data,
const std::string& base64_seed_signature,
const std::string& country_code,
const base::Time& date_fetched,
bool is_delta_compressed,
bool is_gzip_compressed,
variations::VariationsSeed* parsed_seed);
// Updates |kVariationsSeedDate| and logs when previous date was from a
// different day.
void UpdateSeedDateAndLogDayChange(const base::Time& server_date_fetched);
// Reports to UMA that the seed format specified by the server is unsupported.
void ReportUnsupportedSeedFormatError();
// Returns the serial number of the last loaded or stored seed.
const std::string& variations_serial_number() const {
return variations_serial_number_;
// Returns whether the last loaded or stored seed has the country field set.
bool seed_has_country_code() const {
return seed_has_country_code_;
// Returns the invalid signature in base64 format, or an empty string if the
// signature was valid, missing, or if signature verification is disabled.
std::string GetInvalidSignature() const;
// Registers Local State prefs used by this class.
static void RegisterPrefs(PrefRegistrySimple* registry);
// Note: UMA histogram enum - don't re-order or remove entries.
enum VerifySignatureResult {
// Verifies a variations seed (the serialized proto bytes) with the specified
// base-64 encoded signature that was received from the server and returns the
// result. The signature is assumed to be an "ECDSA with SHA-256" signature
// (see kECDSAWithSHA256AlgorithmID in the .cc file). Returns the result of
// signature verification or VARIATIONS_SEED_SIGNATURE_ENUM_SIZE if signature
// verification is not enabled.
virtual VariationsSeedStore::VerifySignatureResult VerifySeedSignature(
const std::string& seed_bytes,
const std::string& base64_seed_signature);
FRIEND_TEST_ALL_PREFIXES(VariationsSeedStoreTest, VerifySeedSignature);
FRIEND_TEST_ALL_PREFIXES(VariationsSeedStoreTest, ApplyDeltaPatch);
// Clears all prefs related to variations seed storage.
void ClearPrefs();
#if defined(OS_ANDROID)
// Imports the variations seed data from Java side during the first
// Chrome for Android run.
void ImportFirstRunJavaSeed();
#endif // OS_ANDROID
// Reads the variations seed data from prefs; returns true on success.
bool ReadSeedData(std::string* seed_data);
// Internal version of |StoreSeedData()| that assumes |seed_data| is not delta
// compressed.
bool StoreSeedDataNoDelta(
const std::string& seed_data,
const std::string& base64_seed_signature,
const std::string& country_code,
const base::Time& date_fetched,
variations::VariationsSeed* parsed_seed);
// Applies a delta-compressed |patch| to |existing_data|, producing the result
// in |output|. Returns whether the operation was successful.
static bool ApplyDeltaPatch(const std::string& existing_data,
const std::string& patch,
std::string* output);
// The pref service used to persist the variations seed.
PrefService* local_state_;
// Cached serial number from the most recently fetched variations seed.
std::string variations_serial_number_;
// Whether the most recently fetched variations seed has the country code
// field set.
bool seed_has_country_code_;
// Keeps track of an invalid signature.
std::string invalid_base64_signature_;
} // namespace variations