[pdata]: Add support to MoveTo for Map, allow avoiding copies

Signed-off-by: Bogdan Drutu <bogdandrutu@gmail.com>

pdata/pcommon/map.go

@@ -225,6 +225,15 @@ func (m Map) Range(f func(k string, v Value) bool) {
 	}
 }
 
+// MoveTo moves all key/values from the current map overriding the destination and
+// resetting the current instance to its zero value
+func (m Map) MoveTo(dest Map) {
+	m.getState().AssertMutable()
+	dest.getState().AssertMutable()
+	*dest.getOrig() = *m.getOrig()
+	*m.getOrig() = nil
+}
+
 // CopyTo copies all elements from the current map overriding the destination.
 func (m Map) CopyTo(dest Map) {
 	dest.getState().AssertMutable()

pdata/pcommon/map_test.go

@@ -375,11 +375,28 @@ func TestMap_FromRaw(t *testing.T) {
 	}, v.Map().AsRaw())
 }
 
+func TestMap_MoveTo(t *testing.T) {
+	dest := NewMap()
+	// Test MoveTo to empty
+	NewMap().MoveTo(dest)
+	assert.Equal(t, 0, dest.Len())
+
+	// Test MoveTo larger slice
+	src := Map(internal.GenerateTestMap())
+	src.MoveTo(dest)
+	assert.EqualValues(t, Map(internal.GenerateTestMap()), dest)
+	assert.Equal(t, 0, src.Len())
+
+	// Test MoveTo from empty to non-empty
+	NewMap().MoveTo(dest)
+	assert.Equal(t, 0, dest.Len())
+}
+
 func TestMap_CopyTo(t *testing.T) {
 	dest := NewMap()
 	// Test CopyTo to empty
 	NewMap().CopyTo(dest)
-	assert.EqualValues(t, 0, dest.Len())
+	assert.Equal(t, 0, dest.Len())
 
 	// Test CopyTo larger slice
 	Map(internal.GenerateTestMap()).CopyTo(dest)