components/leveldb_proto/proto_database.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef COMPONENTS_LEVELDB_PROTO_PROTO_DATABASE_H_
   6 #define COMPONENTS_LEVELDB_PROTO_PROTO_DATABASE_H_
   7
   8 #include <string>
   9 #include <utility>
  10 #include <vector>
  11
  12 #include "base/callback_forward.h"
  13 #include "base/memory/scoped_ptr.h"
  14
  15 namespace base {
  16 class FilePath;
  17 }
  18
  19 namespace leveldb_proto {
  20
  21 // Interface for classes providing persistent storage of Protocol Buffer
  22 // entries (T must be a Proto type extending MessageLite).
  23 template <typename T>
  24 class ProtoDatabase {
  25  public:
  26   using InitCallback = base::Callback<void(bool success)>;
  27   using UpdateCallback = base::Callback<void(bool success)>;
  28   using LoadCallback =
  29       base::Callback<void(bool success, scoped_ptr<std::vector<T>>)>;
  30
  31   // A list of key-value (string, T) tuples.
  32   using KeyEntryVector = std::vector<std::pair<std::string, T>>;
  33
  34   virtual ~ProtoDatabase() {}
  35
  36   // Asynchronously initializes the object. |callback| will be invoked on the
  37   // calling thread when complete.
  38   virtual void Init(const base::FilePath& database_dir,
  39                     const InitCallback& callback) = 0;
  40
  41   // Asynchronously saves |entries_to_save| and deletes entries from
  42   // |keys_to_remove| from the database. |callback| will be invoked on the
  43   // calling thread when complete.
  44   virtual void UpdateEntries(
  45       scoped_ptr<KeyEntryVector> entries_to_save,
  46       scoped_ptr<std::vector<std::string>> keys_to_remove,
  47       const UpdateCallback& callback) = 0;
  48
  49   // Asynchronously loads all entries from the database and invokes |callback|
  50   // when complete.
  51   virtual void LoadEntries(const LoadCallback& callback) = 0;
  52 };
  53
  54 }  // namespace leveldb_proto
  55
  56 #endif  // COMPONENTS_LEVELDB_PROTO_PROTO_DATABASE_H_