dstore/events: Increment

dstore/events.go

@@ -47,6 +47,31 @@ func (m *Mem) EventsAdd(ctx context.Context, path string, data [][]byte) ([]*eve
 	return out, idx, nil
 }
 
+func (m *Mem) Increment(ctx context.Context, path string, name string, n int64) (int64, error) {
+	doc, err := m.Get(ctx, path)
+	if err != nil {
+		return 0, err
+	}
+	val := int64(0)
+	if doc != nil {
+		v, ok := doc.Get(name)
+		if err != nil {
+			return 0, err
+		}
+		if !ok {
+			val = int64(0)
+		} else {
+			val = v.(int64)
+		}
+	}
+
+	next := val + n
+	if err := m.Set(ctx, path, map[string]interface{}{name: next}, MergeAll()); err != nil {
+		return 0, err
+	}
+	return next, nil
+}
+
 // EventPositions returns positions for event logs at the specified paths.
 func (m *Mem) EventPositions(ctx context.Context, paths []string) (map[string]*events.Position, error) {
 	positions := map[string]*events.Position{}

dstore/events/events.go

@@ -40,6 +40,9 @@ type Events interface {
 
 	// EventPositions returns current positions of event logs at the specified paths.
 	EventPositions(ctx context.Context, paths []string) (map[string]*Position, error)
+
+	// Increment document name at path n amount.
+	Increment(ctx context.Context, path string, name string, n int64) (int64, error)
 }
 
 // Direction is ascending or descending.

dstore/events/events_test.go

@@ -191,3 +191,20 @@ func TestEventMarshal(t *testing.T) {
 `
 	require.Equal(t, expected, spew.Sdump(out))
 }
+
+func TestIncrement(t *testing.T) {
+	var err error
+
+	// keys.SetLogger(keys.NewLogger(keys.DebugLevel))
+	eds := dstore.NewMem()
+	clock := tsutil.NewTestClock()
+	eds.SetClock(clock)
+
+	n, err := eds.Increment(context.TODO(), "/test/doc1", "count", 1)
+	require.NoError(t, err)
+	require.Equal(t, int64(1), n)
+
+	n, err = eds.Increment(context.TODO(), "/test/doc1", "count", 5)
+	require.NoError(t, err)
+	require.Equal(t, int64(6), n)
+}