Nil bytes are OK for Get/Set etc

And s/Release/Close/g

db/backend_test.go

@@ -21,27 +21,27 @@ func testBackendGetSetDelete(t *testing.T, backend string) {
 	defer dir.Close()
 	db := NewDB("testdb", backend, dirname)
 
-	// A nonexistent key should return nil, even if the key is empty.
+	// A nonexistent key should return nil, even if the key is empty
 	require.Nil(t, db.Get([]byte("")))
 
-	// A nonexistent key should return nil, even if the key is nil.
+	// A nonexistent key should return nil, even if the key is nil
 	require.Nil(t, db.Get(nil))
 
 	// A nonexistent key should return nil.
 	key := []byte("abc")
 	require.Nil(t, db.Get(key))
 
-	// Set empty ("")
+	// Set empty value.
 	db.Set(key, []byte(""))
 	require.NotNil(t, db.Get(key))
 	require.Empty(t, db.Get(key))
 
-	// Set empty (nil)
+	// Set nil value.
 	db.Set(key, nil)
 	require.NotNil(t, db.Get(key))
 	require.Empty(t, db.Get(key))
 
-	// Delete
+	// Delete.
 	db.Delete(key)
 	require.Nil(t, db.Get(key))
 }
@@ -62,12 +62,13 @@ func withDB(t *testing.T, creator dbCreator, fn func(DB)) {
 }
 
 func TestBackendsNilKeys(t *testing.T) {
-	// test all backends.
+
-	// nil keys are treated as the empty key for most operations.
+	// Test all backends.
 	for dbType, creator := range backends {
 		withDB(t, creator, func(db DB) {
 			t.Run(fmt.Sprintf("Testing %s", dbType), func(t *testing.T) {
 
+				// Nil keys are treated as the empty key for most operations.
 				expect := func(key, value []byte) {
 					if len(key) == 0 { // nil or empty
 						assert.Equal(t, db.Get(nil), db.Get([]byte("")))

db/c_level_db.go

@@ -199,12 +199,12 @@ func newCLevelDBIterator(source *levigo.Iterator, start, end []byte, isReverse b
 	}
 }
 
-func (itr *cLevelDBIterator) Domain() ([]byte, []byte) {
+func (itr cLevelDBIterator) Domain() ([]byte, []byte) {
 	return itr.start, itr.end
 }
 
-func (itr *cLevelDBIterator) Valid() bool {
+func (itr cLevelDBIterator) Valid() bool {
-
+  
 	// Once invalid, forever invalid.
 	if itr.isInvalid {
 		return false
@@ -227,33 +227,33 @@ func (itr *cLevelDBIterator) Valid() bool {
 		return false
 	}
 
-	// Valid
+	// It's valid.
 	return true
 }
 
-func (itr *cLevelDBIterator) Key() []byte {
+func (itr cLevelDBIterator) Key() []byte {
 	itr.assertNoError()
 	itr.assertIsValid()
 	return itr.source.Key()
 }
 
-func (itr *cLevelDBIterator) Value() []byte {
+func (itr cLevelDBIterator) Value() []byte {
 	itr.assertNoError()
 	itr.assertIsValid()
 	return itr.source.Value()
 }
 
-func (itr *cLevelDBIterator) Next() {
+func (itr cLevelDBIterator) Next() {
 	itr.assertNoError()
 	itr.assertIsValid()
 	itr.source.Next()
 }
 
-func (itr *cLevelDBIterator) Close() {
+func (itr cLevelDBIterator) Close() {
 	itr.source.Close()
 }
 
-func (itr *cLevelDBIterator) assertNoError() {
+func (itr cLevelDBIterator) assertNoError() {
 	if err := itr.source.GetError(); err != nil {
 		panic(err)
 	}

db/mem_db.go

@@ -30,7 +30,7 @@ func (db *MemDB) Get(key []byte) []byte {
 	db.mtx.Lock()
 	defer db.mtx.Unlock()
 	key = nonNilBytes(key)
-
+  
 	return db.db[string(key)]
 }
 
@@ -215,4 +215,4 @@ func (itr *memDBIterator) assertIsValid() {
 	if !itr.Valid() {
 		panic("memDBIterator is invalid")
 	}
-}
+}