components/leveldb_proto/proto_database_impl.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_IMPL_H_
   6 #define COMPONENTS_LEVELDB_PROTO_PROTO_DATABASE_IMPL_H_
   7
   8 #include <string>
   9 #include <vector>
  10
  11 #include "base/bind.h"
  12 #include "base/files/file_path.h"
  13 #include "base/memory/scoped_ptr.h"
  14 #include "base/message_loop/message_loop.h"
  15 #include "base/sequenced_task_runner.h"
  16 #include "base/strings/string_util.h"
  17 #include "base/threading/sequenced_worker_pool.h"
  18 #include "base/threading/thread_checker.h"
  19 #include "base/strings/string_split.h"
  20 #include "components/leveldb_proto/leveldb_database.h"
  21 #include "components/leveldb_proto/proto_database.h"
  22
  23 namespace leveldb_proto {
  24
  25 typedef base::StringPairs KeyValueVector;
  26 typedef std::vector<std::string> KeyVector;
  27
  28 // When the ProtoDatabaseImpl instance is deleted, in-progress asynchronous
  29 // operations will be completed and the corresponding callbacks will be called.
  30 // Construction/calls/destruction should all happen on the same thread.
  31 template <typename T>
  32 class ProtoDatabaseImpl : public ProtoDatabase<T> {
  33  public:
  34   // All blocking calls/disk access will happen on the provided |task_runner|.
  35   explicit ProtoDatabaseImpl(
  36       scoped_refptr<base::SequencedTaskRunner> task_runner);
  37
  38   virtual ~ProtoDatabaseImpl();
  39
  40   // ProtoDatabase implementation.
  41   // TODO(cjhopman): Perhaps Init() shouldn't be exposed to users and not just
  42   //     part of the constructor
  43   virtual void Init(const base::FilePath& database_dir,
  44                     typename ProtoDatabase<T>::InitCallback callback) override;
  45   virtual void UpdateEntries(
  46       scoped_ptr<typename ProtoDatabase<T>::KeyEntryVector> entries_to_save,
  47       scoped_ptr<KeyVector> keys_to_remove,
  48       typename ProtoDatabase<T>::UpdateCallback callback) override;
  49   virtual void LoadEntries(
  50       typename ProtoDatabase<T>::LoadCallback callback) override;
  51
  52   // Allow callers to provide their own Database implementation.
  53   void InitWithDatabase(scoped_ptr<LevelDB> database,
  54                         const base::FilePath& database_dir,
  55                         typename ProtoDatabase<T>::InitCallback callback);
  56
  57  private:
  58   base::ThreadChecker thread_checker_;
  59
  60   // Used to run blocking tasks in-order.
  61   scoped_refptr<base::SequencedTaskRunner> task_runner_;
  62
  63   scoped_ptr<LevelDB> db_;
  64
  65   DISALLOW_COPY_AND_ASSIGN(ProtoDatabaseImpl);
  66 };
  67
  68 namespace {
  69
  70 template <typename T>
  71 void RunInitCallback(typename ProtoDatabase<T>::InitCallback callback,
  72                      const bool* success) {
  73   callback.Run(*success);
  74 }
  75
  76 template <typename T>
  77 void RunUpdateCallback(typename ProtoDatabase<T>::UpdateCallback callback,
  78                        const bool* success) {
  79   callback.Run(*success);
  80 }
  81
  82 template <typename T>
  83 void RunLoadCallback(typename ProtoDatabase<T>::LoadCallback callback,
  84                      const bool* success, scoped_ptr<std::vector<T> > entries) {
  85   callback.Run(*success, entries.Pass());
  86 }
  87
  88 void InitFromTaskRunner(LevelDB* database, const base::FilePath& database_dir,
  89                         bool* success) {
  90   DCHECK(success);
  91
  92   // TODO(cjhopman): Histogram for database size.
  93   *success = database->Init(database_dir);
  94 }
  95
  96 template <typename T>
  97 void UpdateEntriesFromTaskRunner(
  98     LevelDB* database,
  99     scoped_ptr<typename ProtoDatabase<T>::KeyEntryVector> entries_to_save,
 100     scoped_ptr<KeyVector> keys_to_remove, bool* success) {
 101   DCHECK(success);
 102   // Serialize the values from Proto to string before passing on to database.
 103   KeyValueVector pairs_to_save;
 104   for (typename ProtoDatabase<T>::KeyEntryVector::iterator it =
 105            entries_to_save->begin();
 106        it != entries_to_save->end(); ++it) {
 107     pairs_to_save.push_back(
 108         std::make_pair(it->first, it->second.SerializeAsString()));
 109   }
 110   *success = database->Save(pairs_to_save, *keys_to_remove);
 111 }
 112
 113 template <typename T>
 114 void LoadEntriesFromTaskRunner(LevelDB* database, std::vector<T>* entries,
 115                                bool* success) {
 116   DCHECK(success);
 117   DCHECK(entries);
 118
 119   entries->clear();
 120   std::vector<std::string> loaded_entries;
 121   *success = database->Load(&loaded_entries);
 122   for (std::vector<std::string>::iterator it = loaded_entries.begin();
 123        it != loaded_entries.end(); ++it) {
 124     T entry;
 125     if (!entry.ParseFromString(*it)) {
 126       DLOG(WARNING) << "Unable to parse leveldb_proto entry " << *it;
 127       // TODO(cjhopman): Decide what to do about un-parseable entries.
 128     }
 129     entries->push_back(entry);
 130   }
 131 }
 132
 133 }  // namespace
 134
 135 template <typename T>
 136 ProtoDatabaseImpl<T>::ProtoDatabaseImpl(
 137     scoped_refptr<base::SequencedTaskRunner> task_runner)
 138     : task_runner_(task_runner) {}
 139
 140 template <typename T>
 141 ProtoDatabaseImpl<T>::~ProtoDatabaseImpl() {
 142   DCHECK(thread_checker_.CalledOnValidThread());
 143   if (!task_runner_->DeleteSoon(FROM_HERE, db_.release())) {
 144     DLOG(WARNING) << "DOM distiller database will not be deleted.";
 145   }
 146 }
 147
 148 template <typename T>
 149 void ProtoDatabaseImpl<T>::Init(
 150     const base::FilePath& database_dir,
 151     typename ProtoDatabase<T>::InitCallback callback) {
 152   DCHECK(thread_checker_.CalledOnValidThread());
 153   InitWithDatabase(scoped_ptr<LevelDB>(new LevelDB()), database_dir, callback);
 154 }
 155
 156 template <typename T>
 157 void ProtoDatabaseImpl<T>::InitWithDatabase(
 158     scoped_ptr<LevelDB> database, const base::FilePath& database_dir,
 159     typename ProtoDatabase<T>::InitCallback callback) {
 160   DCHECK(thread_checker_.CalledOnValidThread());
 161   DCHECK(!db_);
 162   DCHECK(database);
 163   db_.reset(database.release());
 164   bool* success = new bool(false);
 165   task_runner_->PostTaskAndReply(
 166       FROM_HERE, base::Bind(InitFromTaskRunner, base::Unretained(db_.get()),
 167                             database_dir, success),
 168       base::Bind(RunInitCallback<T>, callback, base::Owned(success)));
 169 }
 170
 171 template <typename T>
 172 void ProtoDatabaseImpl<T>::UpdateEntries(
 173     scoped_ptr<typename ProtoDatabase<T>::KeyEntryVector> entries_to_save,
 174     scoped_ptr<KeyVector> keys_to_remove,
 175     typename ProtoDatabase<T>::UpdateCallback callback) {
 176   DCHECK(thread_checker_.CalledOnValidThread());
 177   bool* success = new bool(false);
 178   task_runner_->PostTaskAndReply(
 179       FROM_HERE,
 180       base::Bind(UpdateEntriesFromTaskRunner<T>, base::Unretained(db_.get()),
 181                  base::Passed(&entries_to_save), base::Passed(&keys_to_remove),
 182                  success),
 183       base::Bind(RunUpdateCallback<T>, callback, base::Owned(success)));
 184 }
 185
 186 template <typename T>
 187 void ProtoDatabaseImpl<T>::LoadEntries(
 188     typename ProtoDatabase<T>::LoadCallback callback) {
 189   DCHECK(thread_checker_.CalledOnValidThread());
 190   bool* success = new bool(false);
 191
 192   scoped_ptr<std::vector<T> > entries(new std::vector<T>());
 193   // Get this pointer before entries is base::Passed() so we can use it below.
 194   std::vector<T>* entries_ptr = entries.get();
 195
 196   task_runner_->PostTaskAndReply(
 197       FROM_HERE, base::Bind(LoadEntriesFromTaskRunner<T>,
 198                             base::Unretained(db_.get()), entries_ptr, success),
 199       base::Bind(RunLoadCallback<T>, callback, base::Owned(success),
 200                  base::Passed(&entries)));
 201 }
 202
 203 }  // namespace leveldb_proto
 204
 205 #endif  // COMPONENTS_LEVELDB_PROTO_PROTO_DATABASE_IMPL_H_