Componentize VariationsSeedStore and its unittest

chrome/browser/metrics/variations/variations_seed_store.h

-// 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.
-
-#ifndef CHROME_BROWSER_METRICS_VARIATIONS_VARIATIONS_SEED_STORE_H_
-#define CHROME_BROWSER_METRICS_VARIATIONS_VARIATIONS_SEED_STORE_H_
-
-#include <string>
-
-#include "base/compiler_specific.h"
-#include "base/gtest_prod_util.h"
-#include "base/time/time.h"
-
-class PrefService;
-class PrefRegistrySimple;
-
-namespace variations {
-class VariationsSeed;
-}
-
-namespace chrome_variations {
-
-// VariationsSeedStore is a helper class for reading and writing the variations
-// seed from Local State.
-class VariationsSeedStore {
- public:
-  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_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,
-                     variations::VariationsSeed* parsed_seed);
-
-  // Updates |kVariationsSeedDate| and logs when previous date was from a
-  // different day.
-  void UpdateSeedDateAndLogDayChange(const base::Time& server_date_fetched);
-
-  // 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);
-
- protected:
-  // Note: UMA histogram enum - don't re-order or remove entries.
-  enum VerifySignatureResult {
-    VARIATIONS_SEED_SIGNATURE_MISSING,
-    VARIATIONS_SEED_SIGNATURE_DECODE_FAILED,
-    VARIATIONS_SEED_SIGNATURE_INVALID_SIGNATURE,
-    VARIATIONS_SEED_SIGNATURE_INVALID_SEED,
-    VARIATIONS_SEED_SIGNATURE_VALID,
-    VARIATIONS_SEED_SIGNATURE_ENUM_SIZE,
-  };
-
-  // 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);
-
- private:
-  FRIEND_TEST_ALL_PREFIXES(VariationsSeedStoreTest, VerifySeedSignature);
-  FRIEND_TEST_ALL_PREFIXES(VariationsSeedStoreTest, ApplyDeltaPatch);
-
-  // Clears all prefs related to variations seed storage.
-  void ClearPrefs();
-
-  // 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_;
-
-  DISALLOW_COPY_AND_ASSIGN(VariationsSeedStore);
-};
-
-}  // namespace chrome_variations
-
-#endif  // CHROME_BROWSER_METRICS_VARIATIONS_VARIATIONS_SEED_STORE_H_