Componentize //chrome/browser/prefs/tracked.

chrome/browser/prefs/tracked/pref_hash_store_transaction.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_PREFS_TRACKED_PREF_HASH_STORE_TRANSACTION_H_
-#define CHROME_BROWSER_PREFS_TRACKED_PREF_HASH_STORE_TRANSACTION_H_
-
-#include <string>
-#include <vector>
-
-namespace base {
-class DictionaryValue;
-class Value;
-}  // namespace base
-
-// Used to perform a series of checks/transformations on a PrefHashStore.
-class PrefHashStoreTransaction {
- public:
-  enum ValueState {
-    // The preference value corresponds to its stored hash.
-    UNCHANGED,
-    // The preference has been cleared since the last hash.
-    CLEARED,
-    // The preference value corresponds to its stored hash, but the hash was
-    // calculated using a deprecated hash algorithm which is just as safe as
-    // the current one.
-    SECURE_LEGACY,
-    // The preference value has been changed since the last hash.
-    CHANGED,
-    // No stored hash exists for the preference value.
-    UNTRUSTED_UNKNOWN_VALUE,
-    // No stored hash exists for the preference value, but the current set of
-    // hashes stored is trusted and thus this value can safely be seeded. This
-    // happens when all hashes are already properly seeded and a newly
-    // tracked value needs to be seeded).
-    TRUSTED_UNKNOWN_VALUE,
-    // NULL values are inherently trusted.
-    TRUSTED_NULL_VALUE,
-  };
-
-  // Finalizes any remaining work after the transaction has been performed.
-  virtual ~PrefHashStoreTransaction() {}
-
-  // Checks |initial_value| against the existing stored value hash.
-  virtual ValueState CheckValue(
-      const std::string& path, const base::Value* initial_value) const = 0;
-
-  // Stores a hash of the current |value| of the preference at |path|.
-  virtual void StoreHash(const std::string& path,
-                         const base::Value* value) = 0;
-
-  // Checks |initial_value| against the existing stored hashes for the split
-  // preference at |path|. |initial_split_value| being an empty dictionary or
-  // NULL is equivalent. |invalid_keys| must initially be empty. |invalid_keys|
-  // will not be modified unless the return value is CHANGED, in which case it
-  // will be filled with the keys that are considered invalid (unknown or
-  // changed).
-  virtual ValueState CheckSplitValue(
-      const std::string& path,
-      const base::DictionaryValue* initial_split_value,
-      std::vector<std::string>* invalid_keys) const = 0;
-
-  // Stores hashes for the |value| of the split preference at |path|.
-  // |split_value| being an empty dictionary or NULL is equivalent.
-  virtual void StoreSplitHash(
-      const std::string& path,
-      const base::DictionaryValue* split_value) = 0;
-
-  // Indicates whether the store contains a hash for the preference at |path|.
-  virtual bool HasHash(const std::string& path) const = 0;
-
-  // Sets the hash for the preference at |path|.
-  // If |path| is a split preference |hash| must be a DictionaryValue whose
-  // keys are keys in the split preference and whose values are MACs of the
-  // corresponding values in the split preference.
-  // If |path| is an atomic preference |hash| must be a StringValue
-  // containing a MAC of the preference value.
-  // |hash| should originate from a PrefHashStore sharing the same MAC
-  // parameters as this transaction's store.
-  // The (in)validity of the super MAC will be maintained by this call.
-  virtual void ImportHash(const std::string& path, const base::Value* hash) = 0;
-
-  // Removes the hash stored at |path|. The (in)validity of the super MAC will
-  // be maintained by this call.
-  virtual void ClearHash(const std::string& path) = 0;
-
-  // Indicates whether the super MAC was successfully verified at the beginning
-  // of this transaction.
-  virtual bool IsSuperMACValid() const = 0;
-
-  // Forces a valid super MAC to be stored when this transaction terminates.
-  // Returns true if this results in a change to the store contents.
-  virtual bool StampSuperMac() = 0;
-};
-
-#endif  // CHROME_BROWSER_PREFS_TRACKED_PREF_HASH_STORE_TRANSACTION_H_