From a341819711cda358652ad84b1e507d9559ecabfd Mon Sep 17 00:00:00 2001
From: crupest <crupest@outlook.com>
Date: Tue, 27 Apr 2021 18:22:57 +0800
Subject: refactor: Refactor data services.

---
 .../Services/Data/DataManagerExtensions.cs         | 26 ++++++++++++++++++++++
 1 file changed, 26 insertions(+)
 create mode 100644 BackEnd/Timeline/Services/Data/DataManagerExtensions.cs

(limited to 'BackEnd/Timeline/Services/Data/DataManagerExtensions.cs')

diff --git a/BackEnd/Timeline/Services/Data/DataManagerExtensions.cs b/BackEnd/Timeline/Services/Data/DataManagerExtensions.cs
new file mode 100644
index 00000000..64d35b9b
--- /dev/null
+++ b/BackEnd/Timeline/Services/Data/DataManagerExtensions.cs
@@ -0,0 +1,26 @@
+using System;
+using System.Threading.Tasks;
+
+namespace Timeline.Services.Data
+{
+    public static class DataManagerExtensions
+    {
+        /// <summary>
+        /// Try to get an entry and throw <see cref="DatabaseCorruptedException"/> if not exist.
+        /// </summary>
+        public static async Task<byte[]> GetEntryAndCheck(this IDataManager dataManager, string tag, string notExistMessage)
+        {
+            if (dataManager is null)
+                throw new ArgumentNullException(nameof(dataManager));
+            if (tag is null)
+                throw new ArgumentNullException(nameof(tag));
+            if (notExistMessage is null)
+                throw new ArgumentNullException(nameof(notExistMessage));
+
+            var data = await dataManager.GetEntry(tag);
+            if (data is null)
+                throw new DatabaseCorruptedException(string.Format(Resource.GetEntryAndCheckNotExist, tag, notExistMessage));
+            return data;
+        }
+    }
+}
-- 
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