From 0a06ebac9db50de066a06e304a7cf600af26e3c3 Mon Sep 17 00:00:00 2001
From: Linh Tran Tuan <linhduonggnu@gmail.com>
Date: Tue, 16 Feb 2021 12:25:20 +0900
Subject: [PATCH] NO-ISSUE Adding exists func to pinnable slice (#26)

---
 backup_test.go | 15 +++++++++++----
 db_test.go     | 17 +++++++++++++----
 slice.go       | 35 ++++++++++++++++++-----------------
 slice_test.go  |  8 --------
 4 files changed, 42 insertions(+), 33 deletions(-)
 delete mode 100644 slice_test.go

diff --git a/backup_test.go b/backup_test.go
index ee8b093..3fd88fb 100644
--- a/backup_test.go
+++ b/backup_test.go
@@ -118,9 +118,16 @@ func TestBackupEngine(t *testing.T) {
 		r := NewDefaultReadOptions()
 		defer r.Destroy()
 
-		v3, err := backupDB.GetPinned(r, givenKey)
-		defer v3.Destroy()
-		require.Nil(t, err)
-		require.EqualValues(t, v3.Data(), givenVal2)
+		for i := 0; i < 1000; i++ {
+			v3, err := backupDB.GetPinned(r, givenKey)
+			require.Nil(t, err)
+			require.EqualValues(t, v3.Data(), givenVal2)
+			v3.Destroy()
+
+			v4, err := backupDB.GetPinned(r, []byte("justFake"))
+			require.Nil(t, err)
+			require.False(t, v4.Exists())
+			v4.Destroy()
+		}
 	})
 }
diff --git a/db_test.go b/db_test.go
index 61df886..fe0137b 100755
--- a/db_test.go
+++ b/db_test.go
@@ -51,10 +51,19 @@ func TestDBCRUD(t *testing.T) {
 	require.EqualValues(t, v2.Data(), givenVal2)
 
 	// retrieve pinned
-	v3, err := db.GetPinned(ro, givenKey)
-	defer v3.Destroy()
-	require.Nil(t, err)
-	require.EqualValues(t, v3.Data(), givenVal2)
+	for i := 0; i < 1000; i++ {
+		v3, err := db.GetPinned(ro, givenKey)
+		require.Nil(t, err)
+		require.EqualValues(t, v3.Data(), givenVal2)
+		v3.Destroy()
+		v3.Destroy()
+
+		v3NE, err := db.GetPinned(ro, []byte("justFake"))
+		require.Nil(t, err)
+		require.False(t, v3NE.Exists())
+		v3NE.Destroy()
+		v3NE.Destroy()
+	}
 
 	// delete
 	require.Nil(t, db.Delete(wo, givenKey))
diff --git a/slice.go b/slice.go
index 778081f..3ebb6a8 100644
--- a/slice.go
+++ b/slice.go
@@ -27,17 +27,19 @@ func NewSlice(data *C.char, size C.size_t) *Slice {
 	return &Slice{data, size, false}
 }
 
-// StringToSlice is similar to NewSlice, but can be called with
-// a Go string type. This exists to make testing integration
-// with Gorocksdb easier.
-func StringToSlice(data string) *Slice {
-	return NewSlice(C.CString(data), C.size_t(len(data)))
+// Exists returns if underlying data exists.
+func (s *Slice) Exists() bool {
+	return s.data != nil
 }
 
 // Data returns the data of the slice. If the key doesn't exist this will be a
 // nil slice.
 func (s *Slice) Data() []byte {
-	return charToByte(s.data, s.size)
+	if s.Exists() {
+		return charToByte(s.data, s.size)
+	}
+
+	return nil
 }
 
 // Size returns the size of the data.
@@ -45,11 +47,6 @@ func (s *Slice) Size() int {
 	return int(s.size)
 }
 
-// Exists returns if the key exists
-func (s *Slice) Exists() bool {
-	return s.data != nil
-}
-
 // Free frees the slice data.
 func (s *Slice) Free() {
 	if !s.freed {
@@ -69,16 +66,20 @@ func NewNativePinnableSliceHandle(c *C.rocksdb_pinnableslice_t) *PinnableSliceHa
 	return &PinnableSliceHandle{c}
 }
 
+// Exists returns if underlying data exists.
+func (h *PinnableSliceHandle) Exists() bool {
+	return h.c != nil
+}
+
 // Data returns the data of the slice.
 func (h *PinnableSliceHandle) Data() []byte {
-	if h.c == nil {
-		return nil
+	if h.Exists() {
+		var cValLen C.size_t
+		cValue := C.rocksdb_pinnableslice_value(h.c, &cValLen)
+		return charToByte(cValue, cValLen)
 	}
 
-	var cValLen C.size_t
-	cValue := C.rocksdb_pinnableslice_value(h.c, &cValLen)
-
-	return charToByte(cValue, cValLen)
+	return nil
 }
 
 // Destroy calls the destructor of the underlying pinnable slice handle.
diff --git a/slice_test.go b/slice_test.go
deleted file mode 100644
index 8e58124..0000000
--- a/slice_test.go
+++ /dev/null
@@ -1,8 +0,0 @@
-package grocksdb
-
-import "testing"
-
-func TestStringToSlice(t *testing.T) {
-	slice := StringToSlice("asdf")
-	defer slice.Free()
-}