fix #185. Loading index cache on startup.

Wox.Infrastructure/Storage/JsonStrorage.cs

@@ -0,0 +1,46 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text;
+using Newtonsoft.Json;
+
+namespace Wox.Infrastructure.Storage
+{
+    /// <summary>
+    /// Serialize object using json format.
+    /// </summary>
+    public abstract class JsonStrorage<T> : BaseStorage<T> where T : class, IStorage, new()
+    {
+        protected override string FileSuffix
+        {
+            get { return ".json"; }
+        }
+
+        protected override void LoadInternal()
+        {
+            string json = File.ReadAllText(ConfigPath);
+            if (!string.IsNullOrEmpty(json))
+            {
+                try
+                {
+                    serializedObject = JsonConvert.DeserializeObject<T>(json);
+                }
+                catch (Exception)
+                {
+                    serializedObject = LoadDefault();
+                }
+            }
+            else
+            {
+                serializedObject = LoadDefault();
+            }
+        }
+
+        protected override void SaveInternal()
+        {
+            string json = JsonConvert.SerializeObject(serializedObject, Formatting.Indented);
+            File.WriteAllText(ConfigPath, json);
+        }
+    }
+}