Make ProtoDatabase properly handle failed Init

components/leveldb_proto/leveldb_database.cc

 // 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.
 
 #include "components/leveldb_proto/leveldb_database.h"
 
 #include <string>
 #include <vector>
 
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/strings/string_split.h"
 #include "base/threading/thread_checker.h"
 #include "third_party/leveldatabase/src/include/leveldb/db.h"
 #include "third_party/leveldatabase/src/include/leveldb/iterator.h"
 #include "third_party/leveldatabase/src/include/leveldb/options.h"
 #include "third_party/leveldatabase/src/include/leveldb/slice.h"
 #include "third_party/leveldatabase/src/include/leveldb/status.h"
 #include "third_party/leveldatabase/src/include/leveldb/write_batch.h"
 
 namespace leveldb_proto {
 
 LevelDB::LevelDB() {}
 
-LevelDB::~LevelDB() { DFAKE_SCOPED_LOCK(thread_checker_); }
+LevelDB::~LevelDB() {
+  DFAKE_SCOPED_LOCK(thread_checker_);
+}
 
-bool LevelDB::Init(const base::FilePath& database_dir) {
+bool LevelDB::InitWithOptions(const base::FilePath& database_dir,
+                              const leveldb::Options& options) {
   DFAKE_SCOPED_LOCK(thread_checker_);
 
-  leveldb::Options options;
-  options.create_if_missing = true;
-  options.max_open_files = 0;  // Use minimum.
-
   std::string path = database_dir.AsUTF8Unsafe();
 
   leveldb::DB* db = NULL;
   leveldb::Status status = leveldb::DB::Open(options, path, &db);
   if (status.IsCorruption()) {
     base::DeleteFile(database_dir, true);
     status = leveldb::DB::Open(options, path, &db);
   }
 
   if (status.ok()) {
     CHECK(db);
     db_.reset(db);
     return true;
   }
 
   LOG(WARNING) << "Unable to open " << database_dir.value() << ": "
                << status.ToString();
   return false;
 }
 
+bool LevelDB::Init(const base::FilePath& database_dir) {
+  leveldb::Options options;
+  options.create_if_missing = true;
+  options.max_open_files = 0;  // Use minimum.
+  return InitWithOptions(database_dir, options);
+}
+
 bool LevelDB::Save(const base::StringPairs& entries_to_save,
                    const std::vector<std::string>& keys_to_remove) {
   DFAKE_SCOPED_LOCK(thread_checker_);
+  if (!db_) {
+    return false;
+  }
 
   leveldb::WriteBatch updates;
   for (base::StringPairs::const_iterator it = entries_to_save.begin();
        it != entries_to_save.end();
        ++it) {
     updates.Put(leveldb::Slice(it->first), leveldb::Slice(it->second));
   }
   for (std::vector<std::string>::const_iterator it = keys_to_remove.begin();
        it != keys_to_remove.end(); ++it) {
     updates.Delete(leveldb::Slice(*it));
   }
 
   leveldb::WriteOptions options;
   options.sync = true;
   leveldb::Status status = db_->Write(options, &updates);
   if (status.ok()) return true;
 
   DLOG(WARNING) << "Failed writing leveldb_proto entries: "
                 << status.ToString();
   return false;
 }
 
 bool LevelDB::Load(std::vector<std::string>* entries) {
   DFAKE_SCOPED_LOCK(thread_checker_);
+  if (!db_) {
+    return false;
+  }
 
   leveldb::ReadOptions options;
   scoped_ptr<leveldb::Iterator> db_iterator(db_->NewIterator(options));
   for (db_iterator->SeekToFirst(); db_iterator->Valid(); db_iterator->Next()) {
     leveldb::Slice value_slice = db_iterator->value();
     std::string entry(value_slice.data(), value_slice.size());
     entries->push_back(entry);
   }
   return true;
 }
 
 }  // namespace leveldb_proto