Make ProtoDatabase properly handle failed Init

When Init fails, further Save/Load calls should just fail (and not
crash). This makes the underlying LevelDB properly handle the Init failed case
and adds tests for that.

Adds LevelDB::InitWithOptions to make it easy to have the Init fail in tests.

Review URL: https://codereview.chromium.org/735823004

Cr-Commit-Position: refs/heads/master@{#304944}

3 files changed, 39 insertions, 6 deletions

diff --git a/components/leveldb_proto/leveldb_database.cc b/components/leveldb_proto/leveldb_database.cc
index 65d68a9..45f220e 100644
--- a/components/leveldb_proto/leveldb_database.cc
+++ b/components/leveldb_proto/leveldb_database.cc
@@ -23,14 +23,13 @@ namespace leveldb_proto {
 
 LevelDB::LevelDB() {}
 
-LevelDB::~LevelDB() { DFAKE_SCOPED_LOCK(thread_checker_); }
-
-bool LevelDB::Init(const base::FilePath& database_dir) {
+LevelDB::~LevelDB() {
   DFAKE_SCOPED_LOCK(thread_checker_);
+}
 
-  leveldb::Options options;
-  options.create_if_missing = true;
-  options.max_open_files = 0;  // Use minimum.
+bool LevelDB::InitWithOptions(const base::FilePath& database_dir,
+                              const leveldb::Options& options) {
+  DFAKE_SCOPED_LOCK(thread_checker_);
 
   std::string path = database_dir.AsUTF8Unsafe();
 
@@ -52,9 +51,19 @@ bool LevelDB::Init(const base::FilePath& database_dir) {
   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();
@@ -79,6 +88,9 @@ bool LevelDB::Save(const base::StringPairs& entries_to_save,
 
 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));
diff --git a/components/leveldb_proto/leveldb_database.h b/components/leveldb_proto/leveldb_database.h
index 187a687..faa8199 100644
--- a/components/leveldb_proto/leveldb_database.h
+++ b/components/leveldb_proto/leveldb_database.h
@@ -15,6 +15,7 @@
 
 namespace leveldb {
 class DB;
+struct Options;
 }  // namespace leveldb
 
 namespace leveldb_proto {
@@ -27,6 +28,8 @@ class LevelDB {
   LevelDB();
   virtual ~LevelDB();
 
+  virtual bool InitWithOptions(const base::FilePath& database_dir,
+                               const leveldb::Options& options);
   virtual bool Init(const base::FilePath& database_dir);
   virtual bool Save(const base::StringPairs& pairs_to_save,
                     const std::vector<std::string>& keys_to_remove);
diff --git a/components/leveldb_proto/proto_database_impl_unittest.cc b/components/leveldb_proto/proto_database_impl_unittest.cc
index 095b9d4..e1d3144 100644
--- a/components/leveldb_proto/proto_database_impl_unittest.cc
+++ b/components/leveldb_proto/proto_database_impl_unittest.cc
@@ -15,6 +15,7 @@
 #include "components/leveldb_proto/testing/proto/test.pb.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/leveldatabase/src/include/leveldb/options.h"
 
 using base::MessageLoop;
 using base::ScopedTempDir;
@@ -394,4 +395,21 @@ TEST(ProtoDatabaseImplLevelDBTest, TestDBCloseAndReopen) {
   TestLevelDBSaveAndLoad(true);
 }
 
+TEST(ProtoDatabaseImplLevelDBTest, TestDBInitFail) {
+  ScopedTempDir temp_dir;
+  ASSERT_TRUE(temp_dir.CreateUniqueTempDir());
+
+  leveldb::Options options;
+  options.create_if_missing = false;
+  scoped_ptr<LevelDB> db(new LevelDB());
+
+  KeyValueVector save_entries;
+  std::vector<std::string> load_entries;
+  KeyVector remove_keys;
+
+  EXPECT_FALSE(db->InitWithOptions(temp_dir.path(), options));
+  EXPECT_FALSE(db->Load(&load_entries));
+  EXPECT_FALSE(db->Save(save_entries, remove_keys));
+}
+
 }  // namespace leveldb_proto