Fix memory leak when clean or remove from vector (#118)

* Fix memory leak when clean or remove from vector, close #117

README.md

@@ -195,6 +195,7 @@ indicating that a custom comparison function can be passed.
 - `Copy` return a copies of specified slice
 - `CopyTo` copies all elements in slice a to slice to, return the copied slice.
 - `Fill` repeatedly fills a slice with the specified value
+- `FillZero` fills each element in slice a with zero value.
 - `FillPattern` repeatedly fills a slice with the specified pattern
 - `Replace` replaces every element that equals to old with new
 - `ReplaceIf` replaces every element that make preq returns true with new

README_zh.md

@@ -177,6 +177,7 @@ func TestSkipList_ForEachMutable(t *testing.T) {
 - `Copy` 返回切片的拷贝
 - `CopyTo` 拷贝切片的内容到另一个切片
 - `Fill` 用指定的值重复填充一个切片
+- `FillZero` 用类型的零值重复填充一个切片
 - `FillPattern` 用指定的模式重复填充一个切片
 - `Replace` 替换所有等于指定值的元素为新值
 - `ReplaceIf` 替换所有让函数返回 `true` 的元素为新值

transform.go

@@ -36,6 +36,14 @@ func Fill[T any](a []T, v T) {
 	}
 }
 
+// FillZero fills each element in slice a with zero value.
+//
+// Complexity: O(len(a)).
+func FillZero[T any](a []T) {
+	var zero T
+	Fill(a, zero)
+}
+
 // FillPattern fills elements in slice a with specified pattern.
 //
 // Complexity: O(len(a)).

transform_test.go

@@ -33,6 +33,12 @@ func Test_Fill(t *testing.T) {
 	expectTrue(t, Equal(a, []int{1, 1, 1, 1}))
 }
 
+func Test_FillZero(t *testing.T) {
+	a := []int{1, 2, 3, 4}
+	FillZero(a)
+	expectTrue(t, Equal(a, []int{0, 0, 0, 0}))
+}
+
 func naiveFill[T any](a []T, v T) {
 	for i := range a {
 		a[i] = v

vector.go

@@ -45,6 +45,7 @@ func (v *Vector[T]) Cap() int {
 // Clear erases all elements from the vector. After this call, Len() returns zero.
 // Leaves the Cap() of the vector unchanged.
 func (v *Vector[T]) Clear() {
+	FillZero(*v)
 	*v = (*v)[0:0]
 }
 
@@ -92,7 +93,9 @@ func (v *Vector[T]) PushBack(x T) {
 // It must be called when IsEmpty() returned false,
 // otherwise it will panic.
 func (v *Vector[T]) PopBack() T {
+	var zero T
 	e := (*v)[v.Len()-1]
+	(*v)[len(*v)-1] = zero
 	*v = (*v)[0 : v.Len()-1]
 	return e
 }
@@ -149,7 +152,9 @@ func (v *Vector[T]) Remove(i int) {
 
 // RemoveRange removes the elements in the range[i, j) from the vector.
 func (v *Vector[T]) RemoveRange(i, j int) {
+	oldV := *v
 	*v = append((*v)[:i], (*v)[j:]...)
+	FillZero(oldV[v.Len():])
 }
 
 // RemoveLength removes the elements in the range[i, i+len) from the vector.

vector_test.go

@@ -100,6 +100,13 @@ func Test_Vector_PopBack(t *testing.T) {
 	expectPanic(t, func() { v.PopBack() })
 }
 
+func Test_Vector_PopBack_Clear(t *testing.T) {
+	v := VectorOf(1, 2)
+	oldV := v
+	v.PopBack()
+	expectEq(t, oldV[1], 0)
+}
+
 func Test_Vector_Back(t *testing.T) {
 	v := VectorOf(1)
 	expectEq(t, v.Back(), 1)
@@ -134,29 +141,37 @@ func Test_Vector_Insert_Cap(t *testing.T) {
 
 func Test_Vector_Remove(t *testing.T) {
 	v := VectorOf(1, 2, 3)
+	oldV := v
 	v.Remove(1)
 	expectEq(t, v.Len(), 2)
 	expectEq(t, v.Cap(), 3)
 	expectEq(t, v[0], 1)
 	expectEq(t, v[1], 3)
+	expectEq(t, oldV[2], 0)
 }
 
 func Test_Vector_RemoveRange(t *testing.T) {
 	v := VectorOf(1, 2, 3, 4)
+	oldV := v
 	v.RemoveRange(1, 3)
 	expectEq(t, v.Len(), 2)
 	expectEq(t, v.Cap(), 4)
 	expectEq(t, v[0], 1)
 	expectEq(t, v[1], 4)
+	expectEq(t, oldV[2], 0)
+	expectEq(t, oldV[3], 0)
 }
 
 func Test_Vector_RemoveLength(t *testing.T) {
 	v := VectorOf(1, 2, 3, 4)
+	oldV := v
 	v.RemoveLength(1, 2)
 	expectEq(t, v.Len(), 2)
 	expectEq(t, v.Cap(), 4)
 	expectEq(t, v[0], 1)
 	expectEq(t, v[1], 4)
+	expectEq(t, oldV[2], 0)
+	expectEq(t, oldV[3], 0)
 }
 
 func Test_Vector_ForEach(t *testing.T) {