From e36faaa0b5fad5c2a6d8c4b3825d1b458383da42 Mon Sep 17 00:00:00 2001
From: Tian Liao <tilia@microsoft.com>
Date: Fri, 25 Oct 2024 10:46:44 +0800
Subject: [PATCH] DeflateUtils

---
 src/Calculator/Calculator.csproj         |  1 +
 src/Calculator/Common/LaunchArguments.cs |  6 +++-
 src/Calculator/Utils/DeflateUtils.cs     | 44 ++++++++++++++++++++++++
 src/Calculator/Views/MainPage.xaml.cs    | 20 ++---------
 4 files changed, 52 insertions(+), 19 deletions(-)
 create mode 100644 src/Calculator/Utils/DeflateUtils.cs

diff --git a/src/Calculator/Calculator.csproj b/src/Calculator/Calculator.csproj
index 6dee5aa8..00bdc954 100644
--- a/src/Calculator/Calculator.csproj
+++ b/src/Calculator/Calculator.csproj
@@ -165,6 +165,7 @@
     <Compile Include="Converters\RadixToStringConverter.cs" />
     <Compile Include="Converters\VisibilityNegationConverter.cs" />
     <Compile Include="Selectors\NavViewMenuItemTemplateSelector.cs" />
+    <Compile Include="Utils\DeflateUtils.cs" />
     <Compile Include="Utils\ResourceVirtualKey.cs" />
     <Compile Include="Utils\ResourceString.cs" />
     <Compile Include="Utils\JsonUtils.cs" />
diff --git a/src/Calculator/Common/LaunchArguments.cs b/src/Calculator/Common/LaunchArguments.cs
index 1906c14f..3d60896d 100644
--- a/src/Calculator/Common/LaunchArguments.cs
+++ b/src/Calculator/Common/LaunchArguments.cs
@@ -15,7 +15,11 @@ namespace CalculatorApp
         {
             result = null;
             var protoArgs = args as IProtocolActivatedEventArgs;
-            if (protoArgs == null || protoArgs.Uri == null)
+            if (protoArgs == null ||
+                protoArgs.Uri == null ||
+                protoArgs.Uri.Segments == null ||
+                protoArgs.Uri.Segments.Length < 2 ||
+                protoArgs.Uri.Segments[0] != "snapshot/")
             {
                 return false;
             }
diff --git a/src/Calculator/Utils/DeflateUtils.cs b/src/Calculator/Utils/DeflateUtils.cs
new file mode 100644
index 00000000..1cdb4c6c
--- /dev/null
+++ b/src/Calculator/Utils/DeflateUtils.cs
@@ -0,0 +1,44 @@
+using System;
+using System.IO;
+using System.IO.Compression;
+using System.Text;
+
+namespace CalculatorApp
+{
+    internal static class DeflateUtils
+    {
+        public static byte[] Compress(string text)
+        {
+            var data = Encoding.UTF8.GetBytes(text);
+            using (var compressed = new MemoryStream())
+            {
+                using (var deflater = new DeflateStream(compressed, CompressionLevel.Optimal))
+                {
+                    deflater.Write(data, 0, data.Length);
+                }
+                return compressed.ToArray();
+            }
+        }
+
+        public static bool TryDecompress(byte[] data, out string text)
+        {
+            text = null;
+            try
+            {
+                using (var srcStream = new MemoryStream(data))
+                using (var deflateStream = new DeflateStream(srcStream, CompressionMode.Decompress))
+                using (var resultStream = new MemoryStream())
+                {
+                    deflateStream.CopyTo(resultStream);
+                    byte[] decompressed = resultStream.ToArray();
+                    text = Encoding.UTF8.GetString(decompressed);
+                    return true;
+                }
+            }
+            catch (Exception)
+            {
+                return false;
+            }
+        }
+    }
+}
diff --git a/src/Calculator/Views/MainPage.xaml.cs b/src/Calculator/Views/MainPage.xaml.cs
index a3f142bc..e7efa4c6 100644
--- a/src/Calculator/Views/MainPage.xaml.cs
+++ b/src/Calculator/Views/MainPage.xaml.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.ComponentModel;
+using System.Text.Json;
 using System.Threading.Tasks;
 
 using Windows.ApplicationModel.UserActivities;
@@ -23,10 +24,6 @@ using CalculatorApp.ViewModel.Common;
 using CalculatorApp.ViewModel.Common.Automation;
 
 using wuxc = Windows.UI.Xaml.Controls;
-using System.Text.Json;
-using System.IO.Compression;
-using System.IO;
-using System.Text;
 
 namespace CalculatorApp
 {
@@ -78,7 +75,7 @@ namespace CalculatorApp
                     try
                     {
                         var json = JsonSerializer.Serialize(new ApplicationSnapshotAlias { Value = Model.Snapshot });
-                        embeddedData = Convert.ToBase64String(Compress(json));
+                        embeddedData = Convert.ToBase64String(DeflateUtils.Compress(json));
                     }
                     catch (Exception)
                     {
@@ -720,19 +717,6 @@ namespace CalculatorApp
             await dialog.ShowAsync();
         }
 
-        private static byte[] Compress(string text)
-        {
-            var data = Encoding.UTF8.GetBytes(text);
-            using (var compressed = new MemoryStream())
-            {
-                using (var deflater = new DeflateStream(compressed, CompressionLevel.Optimal))
-                {
-                    deflater.Write(data, 0, data.Length);
-                }
-                return compressed.ToArray();
-            }
-        }
-
         private Calculator m_calculator;
         private GraphingCalculator m_graphingCalculator;
         private UnitConverter m_converter;