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.h"
  13 #include "base/files/file_path.h"
  14 #include "base/memory/scoped_ptr.h"
  15
  16 namespace leveldb_proto {
  17
  18 // Interface for classes providing persistent storage of Protocol Buffer
  19 // entries (T must be a Proto type extending MessageLite).
  20 template <typename T>
  21 class ProtoDatabase {
  22  public:
  23   typedef base::Callback<void(bool success)> InitCallback;
  24   typedef base::Callback<void(bool success)> UpdateCallback;
  25   typedef base::Callback<void(bool success, scoped_ptr<std::vector<T> >)>
  26       LoadCallback;
  27   // A list of key-value (string, T) tuples.
  28   typedef std::vector<std::pair<std::string, T> > KeyEntryVector;
  29
  30   virtual ~ProtoDatabase() {}
  31
  32   // Asynchronously initializes the object. |callback| will be invoked on the
  33   // calling thread when complete.
  34   virtual void Init(const base::FilePath& database_dir,
  35                     InitCallback callback) = 0;
  36
  37   // Asynchronously saves |entries_to_save| and deletes entries from
  38   // |keys_to_remove| from the database. |callback| will be invoked on the
  39   // calling thread when complete.
  40   virtual void UpdateEntries(
  41       scoped_ptr<KeyEntryVector> entries_to_save,
  42       scoped_ptr<std::vector<std::string> > keys_to_remove,
  43       UpdateCallback callback) = 0;
  44
  45   // Asynchronously loads all entries from the database and invokes |callback|
  46   // when complete.
  47   virtual void LoadEntries(LoadCallback callback) = 0;
  48 };
  49
  50 }  // namespace leveldb_proto
  51
  52 #endif  // COMPONENTS_LEVELDB_PROTO_PROTO_DATABASE_H_