cache: Fix ApplyModifications for pointer fields

Signed-off-by: Dave Tucker <[email protected]>

cache/cache.go

@@ -780,6 +780,7 @@ func (t *TableCache) CreateModel(tableName string, row *ovsdb.Row, uuid string)
 }
 
 // ApplyModifications applies the contents of a RowUpdate2.Modify to a model
+// nolint: gocyclo
 func (t *TableCache) ApplyModifications(tableName string, base model.Model, update ovsdb.Row) error {
 	table := t.mapper.Schema.Table(tableName)
 	if table == nil {
@@ -797,19 +798,29 @@ func (t *TableCache) ApplyModifications(tableName string, base model.Model, upda
 		if k == "_uuid" {
 			continue
 		}
-		value, err := ovsdb.OvsToNative(schema.Column(k), v)
+
+		current, err := info.FieldByColumn(k)
+		if err != nil {
+			return err
+		}
+
+		var value interface{}
+		value, err = ovsdb.OvsToNative(schema.Column(k), v)
+		// we can overflow the max of a set with min: 0, max: 1 here because of the update2/update3 notation
+		// which to replace "foo" with "bar" would send a set with ["foo", "bar"]
+		if err != nil && schema.Column(k).Type == ovsdb.TypeSet && schema.Column(k).TypeObj.Max() == 1 {
+			value, err = ovsdb.OvsToNativeSlice(schema.Column(k).TypeObj.Key.Type, v)
+		}
 		if err != nil {
 			return err
 		}
 		nv := reflect.ValueOf(value)
 
-		switch nv.Kind() {
+		switch reflect.ValueOf(current).Kind() {
 		case reflect.Slice, reflect.Array:
 			// The difference between two sets are all elements that only belong to one of the sets.
-
 			// Iterate new values
 			for i := 0; i < nv.Len(); i++ {
-
 				// search for match in base values
 				baseValue, err := info.FieldByColumn(k)
 				if err != nil {
@@ -837,7 +848,30 @@ func (t *TableCache) ApplyModifications(tableName string, base model.Model, upda
 					}
 				}
 			}
-
+		case reflect.Ptr:
+			// if NativeToOVS was successful, then simply assign
+			if nv.Type() == reflect.ValueOf(current).Type() {
+				err = info.SetField(k, nv.Interface())
+				return err
+			}
+			// With a pointer type, an update value could be a set with 2 elements [old, new]
+			if nv.Len() != 2 {
+				panic("expected a slice with 2 elements")
+			}
+			// the new value is the value in the slice which isn't equal to the existing string
+			for i := 0; i < nv.Len(); i++ {
+				baseValue, err := info.FieldByColumn(k)
+				if err != nil {
+					return err
+				}
+				bv := reflect.ValueOf(baseValue)
+				if nv.Index(i) != bv {
+					err = info.SetField(k, nv.Index(i).Addr().Interface())
+					if err != nil {
+						return err
+					}
+				}
+			}
 		case reflect.Map:
 			// The difference between two maps are all key-value pairs whose keys appears in only one of the maps,
 			// plus the key-value pairs whose keys appear in both maps but with different values.

cache/cache_test.go

@@ -1179,7 +1179,9 @@ func TestTableCacheApplyModifications(t *testing.T) {
 		Set   []string          `ovsdb:"set"`
 		Map   map[string]string `ovsdb:"map"`
 		Map2  map[string]string `ovsdb:"map2"`
+		Ptr   *string           `ovsdb:"ptr"`
 	}
+	aEmptySet, _ := ovsdb.NewOvsSet([]string{})
 	aFooSet, _ := ovsdb.NewOvsSet([]string{"foo"})
 	aFooBarSet, _ := ovsdb.NewOvsSet([]string{"foo", "bar"})
 	aFooMap, _ := ovsdb.NewOvsMap(map[string]string{"foo": "bar"})
@@ -1188,6 +1190,10 @@ func TestTableCacheApplyModifications(t *testing.T) {
 		"bar": "baz",
 		"baz": "quux",
 	})
+	wallace := "wallace"
+	aWallaceSet, _ := ovsdb.NewOvsSet([]string{wallace})
+	gromit := "gromit"
+	aWallaceGromitSet, _ := ovsdb.NewOvsSet([]string{wallace, gromit})
 	tests := []struct {
 		name     string
 		update   ovsdb.Row
@@ -1224,7 +1230,6 @@ func TestTableCacheApplyModifications(t *testing.T) {
 			&testDBModel{Set: []string{"foo"}},
 			&testDBModel{Set: []string{"bar"}},
 		},
-
 		{
 			"replace map value",
 			ovsdb.Row{"map": aFooMap},
@@ -1252,6 +1257,24 @@ func TestTableCacheApplyModifications(t *testing.T) {
 				Map2: map[string]string{"foo": "bar"},
 			},
 		},
+		{
+			"set optional value",
+			ovsdb.Row{"ptr": aWallaceSet},
+			&testDBModel{Ptr: nil},
+			&testDBModel{Ptr: &wallace},
+		},
+		{
+			"replace optional value",
+			ovsdb.Row{"ptr": aWallaceGromitSet},
+			&testDBModel{Ptr: &wallace},
+			&testDBModel{Ptr: &gromit},
+		},
+		{
+			"delete optional value",
+			ovsdb.Row{"ptr": aEmptySet},
+			&testDBModel{Ptr: &wallace},
+			&testDBModel{Ptr: nil},
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -1268,7 +1291,8 @@ func TestTableCacheApplyModifications(t *testing.T) {
 					  "value": { "type": "string" },
 					  "set": { "type": { "key": { "type": "string" }, "min": 0,	"max": "unlimited" } },
 					  "map": { "type": { "key": "string", "max": "unlimited", "min": 0, "value": "string" } },
-					  "map2": { "type": { "key": "string", "max": "unlimited", "min": 0, "value": "string" } }
+					  "map2": { "type": { "key": "string", "max": "unlimited", "min": 0, "value": "string" } },
+					  "ptr": { "type": { "key": { "type": "string" }, "min": 0,	"max": 1 } }
 					}
 				  }
 				}

ovsdb/updates2.go

@@ -81,8 +81,6 @@ func (r *RowUpdate2) Merge(new *RowUpdate2) {
 							oMap.GoMap[newK] = newV
 						}
 					}
-				default:
-					panic("ARGH!")
 				}
 			}
 		}