Add message dialog asking to save on quit

src/text_editor/text_editor.cpp

@@ -408,6 +408,30 @@ void OnCommand(Event event) {
         String16 string16 = ToString16(scratch, event.text);
         Replace(active.view, string16);
     }
+
+    if (event.kind == EVENT_QUIT) {
+        Scratch scratch;
+        bool do_quit = true;
+        For (Buffers) {
+            if (it->garbage || it->dont_warn_on_save) {
+                continue;
+            }
+            if (it->dirty) {
+                String message = Format(scratch, "Do you really want to quit? Unsaved buffer: %S", it->name);
+                int save = SaveMessageBox("There are unsaved changes, do you really want to quit!", message.data);
+                if (save == 0) {
+                    break;
+                }
+                if (save == 2) {
+                    SaveBuffer(it);
+                }
+            }
+        }
+
+        if (do_quit) {
+            AppIsRunning = false;
+        }
+    }
 }
 
 void GarbageCollect() {
@@ -556,10 +580,6 @@ void MainLoop() {
         if (it.kind != 1) {
             if (!Testing) Serialize(&ser, &it);
         }
-        if (it.kind == EVENT_QUIT) {
-            AppIsRunning = false;
-            return;
-        }
 
         if (it.xwindow == 0 || it.ywindow == 0) {
             int xwindow, ywindow;