[d] Add import/export feature

dfssd/gui/save.go

+package gui
+
+import (
+	"encoding/json"
+	"io/ioutil"
+	"strconv"
+)
+
+func (w *Window) Save(filename string) {
+	data, err := json.Marshal(w.scene)
+	if err != nil {
+		w.StatusBar().ShowMessage(err.Error())
+		return
+	}
+
+	err = ioutil.WriteFile(filename, data, 0600)
+	if err != nil {
+		w.StatusBar().ShowMessage(err.Error())
+		return
+	}
+	w.StatusBar().ShowMessage("Saved file as " + filename)
+}
+
+func (w *Window) Open(filename string) {
+	data, err := ioutil.ReadFile(filename)
+	if err != nil {
+		w.StatusBar().ShowMessage(err.Error())
+		return
+	}
+
+	newScene := &Scene{}
+	err = json.Unmarshal(data, newScene)
+	if err != nil {
+		w.StatusBar().ShowMessage(err.Error())
+		return
+	}
+
+	w.scene = newScene
+	w.StatusBar().ShowMessage("Imported file from " + filename + " (" + strconv.Itoa(len(w.scene.Events)) + " events)")
+	w.initScene()
+}

dfssd/gui/window.go

@@ -70,10 +70,22 @@ func (w *Window) addActions() {
 	openAct := ui.NewActionWithTextParent("&Open", w)
 	openAct.SetShortcuts(ui.QKeySequence_Open)
 	openAct.SetStatusTip("Open a demonstration file")
+	openAct.OnTriggered(func() {
+		filename := ui.QFileDialogGetOpenFileName()
+		if filename != "" {
+			w.Open(filename)
+		}
+	})
 
 	saveAct := ui.NewActionWithTextParent("&Save", w)
 	saveAct.SetShortcuts(ui.QKeySequence_Save)
 	saveAct.SetStatusTip("Save a demonstration file")
+	saveAct.OnTriggered(func() {
+		filename := ui.QFileDialogGetSaveFileName()
+		if filename != "" {
+			w.Save(filename)
+		}
+	})
 
 	w.MenuBar().AddAction(openAct)
 	w.MenuBar().AddAction(saveAct)