Minor LevelDB cleanups (#1401)

* Add leveldb_transaction* to the CMake build

* Use std::unique_ptr for leveldb::DB pointers

9 files changed, 18 insertions, 10 deletions

diff --git a/Firestore/Example/Tests/Local/FSTLevelDBMigrationsTests.mm b/Firestore/Example/Tests/Local/FSTLevelDBMigrationsTests.mm
index 3da8083..e6ab720 100644
--- a/Firestore/Example/Tests/Local/FSTLevelDBMigrationsTests.mm
+++ b/Firestore/Example/Tests/Local/FSTLevelDBMigrationsTests.mm
@@ -42,7 +42,7 @@ using leveldb::Status;
 @end
 
 @implementation FSTLevelDBMigrationsTests {
-  std::shared_ptr<DB> _db;
+  std::unique_ptr<DB> _db;
 }
 
 - (void)setUp {
@@ -62,12 +62,12 @@ using leveldb::Status;
 }
 
 - (void)testAddsTargetGlobal {
-  FSTPBTargetGlobal *metadata = [FSTLevelDBQueryCache readTargetMetadataFromDB:_db];
+  FSTPBTargetGlobal *metadata = [FSTLevelDBQueryCache readTargetMetadataFromDB:_db.get()];
   XCTAssertNil(metadata, @"Not expecting metadata yet, we should have an empty db");
   LevelDbTransaction transaction(_db.get(), "testAddsTargetGlobal");
   [FSTLevelDBMigrations runMigrationsWithTransaction:&transaction];
   transaction.Commit();
-  metadata = [FSTLevelDBQueryCache readTargetMetadataFromDB:_db];
+  metadata = [FSTLevelDBQueryCache readTargetMetadataFromDB:_db.get()];
   XCTAssertNotNil(metadata, @"Migrations should have added the metadata");
 }
 
@@ -107,7 +107,7 @@ using leveldb::Status;
     LevelDbTransaction transaction(_db.get(), "testCountsQueries");
     [FSTLevelDBMigrations runMigrationsWithTransaction:&transaction];
     transaction.Commit();
-    FSTPBTargetGlobal *metadata = [FSTLevelDBQueryCache readTargetMetadataFromDB:_db];
+    FSTPBTargetGlobal *metadata = [FSTLevelDBQueryCache readTargetMetadataFromDB:_db.get()];
     XCTAssertEqual(expected, metadata.targetCount, @"Failed to count all of the targets we added");
   }
 }
diff --git a/Firestore/Example/Tests/Local/FSTLevelDBTransactionTests.mm b/Firestore/Example/Tests/Local/FSTLevelDBTransactionTests.mm
index 29f5d6c..5c2718b 100644
--- a/Firestore/Example/Tests/Local/FSTLevelDBTransactionTests.mm
+++ b/Firestore/Example/Tests/Local/FSTLevelDBTransactionTests.mm
@@ -46,7 +46,7 @@ using firebase::firestore::local::LevelDbTransaction;
 @end
 
 @implementation FSTLevelDBTransactionTests {
-  std::shared_ptr<DB> _db;
+  std::unique_ptr<DB> _db;
 }
 
 - (void)setUp {
diff --git a/Firestore/Source/Local/FSTLevelDB.h b/Firestore/Source/Local/FSTLevelDB.h
index 95b80a6..a56c133 100644
--- a/Firestore/Source/Local/FSTLevelDB.h
+++ b/Firestore/Source/Local/FSTLevelDB.h
@@ -95,7 +95,7 @@ NS_ASSUME_NONNULL_BEGIN
 + (NSString *)descriptionOfStatus:(leveldb::Status)status;
 
 /** The native db pointer, allocated during start. */
-@property(nonatomic, assign, readonly) std::shared_ptr<leveldb::DB> ptr;
+@property(nonatomic, assign, readonly) leveldb::DB *ptr;
 
 @property(nonatomic, readonly) firebase::firestore::local::LevelDbTransaction *currentTransaction;
 
diff --git a/Firestore/Source/Local/FSTLevelDB.mm b/Firestore/Source/Local/FSTLevelDB.mm
index 9f75a3e..9dc50a2 100644
--- a/Firestore/Source/Local/FSTLevelDB.mm
+++ b/Firestore/Source/Local/FSTLevelDB.mm
@@ -17,6 +17,7 @@
 #import "Firestore/Source/Local/FSTLevelDB.h"
 
 #include <memory>
+#include <utility>
 
 #import "FIRFirestoreErrors.h"
 #import "Firestore/Source/Local/FSTLevelDBMigrations.h"
@@ -60,6 +61,7 @@ using leveldb::WriteOptions;
 
 @implementation FSTLevelDB {
   std::unique_ptr<LevelDbTransaction> _transaction;
+  std::unique_ptr<leveldb::DB> _ptr;
   FSTTransactionRunner _transactionRunner;
 }
 
@@ -82,6 +84,10 @@ using leveldb::WriteOptions;
   return self;
 }
 
+- (leveldb::DB *)ptr {
+  return _ptr.get();
+}
+
 - (const FSTTransactionRunner &)run {
   return _transactionRunner;
 }
diff --git a/Firestore/Source/Local/FSTLevelDBMutationQueue.h b/Firestore/Source/Local/FSTLevelDBMutationQueue.h
index 034738f..911fa37 100644
--- a/Firestore/Source/Local/FSTLevelDBMutationQueue.h
+++ b/Firestore/Source/Local/FSTLevelDBMutationQueue.h
@@ -51,7 +51,7 @@ NS_ASSUME_NONNULL_BEGIN
  * Returns one larger than the largest batch ID that has been stored. If there are no mutations
  * returns 0. Note that batch IDs are global.
  */
-+ (FSTBatchID)loadNextBatchIDFromDB:(std::shared_ptr<leveldb::DB>)db;
++ (FSTBatchID)loadNextBatchIDFromDB:(leveldb::DB *)db;
 
 @end
 
diff --git a/Firestore/Source/Local/FSTLevelDBMutationQueue.mm b/Firestore/Source/Local/FSTLevelDBMutationQueue.mm
index 3b4687c..94ab8a5 100644
--- a/Firestore/Source/Local/FSTLevelDBMutationQueue.mm
+++ b/Firestore/Source/Local/FSTLevelDBMutationQueue.mm
@@ -132,7 +132,7 @@ using leveldb::WriteOptions;
   self.metadata = metadata;
 }
 
-+ (FSTBatchID)loadNextBatchIDFromDB:(std::shared_ptr<DB>)db {
++ (FSTBatchID)loadNextBatchIDFromDB:(DB *)db {
   // TODO(gsoltis): implement Prev() and SeekToLast() on LevelDbTransaction::Iterator, then port
   // this to a transaction.
   std::unique_ptr<Iterator> it(db->NewIterator(LevelDbTransaction::DefaultReadOptions()));
diff --git a/Firestore/Source/Local/FSTLevelDBQueryCache.h b/Firestore/Source/Local/FSTLevelDBQueryCache.h
index 2cd6758..f756d9e 100644
--- a/Firestore/Source/Local/FSTLevelDBQueryCache.h
+++ b/Firestore/Source/Local/FSTLevelDBQueryCache.h
@@ -36,7 +36,7 @@ NS_ASSUME_NONNULL_BEGIN
  * Retrieves the global singleton metadata row from the given database, if it exists.
  * TODO(gsoltis): remove this method once fully ported to transactions.
  */
-+ (nullable FSTPBTargetGlobal *)readTargetMetadataFromDB:(std::shared_ptr<leveldb::DB>)db;
++ (nullable FSTPBTargetGlobal *)readTargetMetadataFromDB:(leveldb::DB *)db;
 
 /**
  * Retrieves the global singleton metadata row using the given transaction, if it exists.
diff --git a/Firestore/Source/Local/FSTLevelDBQueryCache.mm b/Firestore/Source/Local/FSTLevelDBQueryCache.mm
index f28370a..31c2a2e 100644
--- a/Firestore/Source/Local/FSTLevelDBQueryCache.mm
+++ b/Firestore/Source/Local/FSTLevelDBQueryCache.mm
@@ -85,7 +85,7 @@ using firebase::firestore::model::DocumentKeySet;
   return proto;
 }
 
-+ (nullable FSTPBTargetGlobal *)readTargetMetadataFromDB:(std::shared_ptr<DB>)db {
++ (nullable FSTPBTargetGlobal *)readTargetMetadataFromDB:(DB *)db {
   std::string key = [FSTLevelDBTargetGlobalKey key];
   std::string value;
   Status status = db->Get([FSTLevelDB standardReadOptions], key, &value);
diff --git a/Firestore/core/src/firebase/firestore/local/CMakeLists.txt b/Firestore/core/src/firebase/firestore/local/CMakeLists.txt
index 089d03c..4d39c3d 100644
--- a/Firestore/core/src/firebase/firestore/local/CMakeLists.txt
+++ b/Firestore/core/src/firebase/firestore/local/CMakeLists.txt
@@ -17,6 +17,8 @@ cc_library(
   SOURCES
     leveldb_key.h
     leveldb_key.cc
+    leveldb_transaction.h
+    leveldb_transaction.cc
   DEPENDS
     LevelDB::LevelDB
     absl_strings