refactor: rewrite Commands.QueryFileContent and use it instead of GetImageFileAsBitmap

Author: love-linger

src/Commands/GetImageFileAsBitmap.cs

@@ -1,28 +1,39 @@
-using System.Text;
+using System;
+using System.Diagnostics;
+using System.IO;
 
 namespace SourceGit.Commands
 {
-    public class QueryFileContent : Command
+    public static class QueryFileContent
     {
-        public QueryFileContent(string repo, string revision, string file)
+        public static Stream Run(string repo, string revision, string file)
         {
-            WorkingDirectory = repo;
-            Context = repo;
-            Args = $"show {revision}:\"{file}\"";
-        }
+            var starter = new ProcessStartInfo();
+            starter.WorkingDirectory = repo;
+            starter.FileName = Native.OS.GitExecutable;
+            starter.Arguments = $"show {revision}:\"{file}\"";
+            starter.UseShellExecute = false;
+            starter.CreateNoWindow = true;
+            starter.WindowStyle = ProcessWindowStyle.Hidden;
+            starter.RedirectStandardOutput = true;
 
-        public string Result()
-        {
-            Exec();
-            return _builder.ToString();
-        }
+            try
+            {
+                var stream = new MemoryStream();
+                var proc = new Process() { StartInfo = starter };
+                proc.Start();
+                proc.StandardOutput.BaseStream.CopyTo(stream);
+                proc.WaitForExit();
+                proc.Close();
 
-        protected override void OnReadline(string line)
-        {
-            _builder.Append(line);
-            _builder.Append('\n');
+                stream.Position = 0;
+                return stream;
+            }
+            catch (Exception e)
+            {
+                App.RaiseException(repo, $"Failed to query file content: {e}");
+                return null;
+            }
         }
-
-        private readonly StringBuilder _builder = new StringBuilder();
     }
 }

src/Commands/QueryFileContent.cs

@@ -4,6 +4,7 @@
 using System.Threading.Tasks;
 
 using Avalonia.Controls;
+using Avalonia.Media.Imaging;
 using Avalonia.Platform.Storage;
 using Avalonia.Threading;
 
@@ -255,7 +256,7 @@ public ContextMenu CreateChangeContextMenu(Models.Change change)
                 menu.Items.Add(blame);
                 menu.Items.Add(explore);
                 menu.Items.Add(new MenuItem { Header = "-" });
-            }            
+            }
 
             var copyPath = new MenuItem();
             copyPath.Header = App.Text("CopyPath");
@@ -473,7 +474,8 @@ private void RefreshViewRevisionFile(Models.Object file)
                             var ext = Path.GetExtension(file.Path);
                             if (IMG_EXTS.Contains(ext))
                             {
-                                var bitmap = Commands.GetImageFileAsBitmap.Run(_repo, _commit.SHA, file.Path);
+                                var stream = Commands.QueryFileContent.Run(_repo, _commit.SHA, file.Path);
+                                var bitmap = stream != null ? new Bitmap(stream) : null as Bitmap;
                                 Dispatcher.UIThread.Invoke(() =>
                                 {
                                     ViewRevisionFileContent = new Models.RevisionImageFile() { Image = bitmap };
@@ -491,7 +493,8 @@ private void RefreshViewRevisionFile(Models.Object file)
                             return;
                         }
 
-                        var content = new Commands.QueryFileContent(_repo, _commit.SHA, file.Path).Result();
+                        var contentStream = Commands.QueryFileContent.Run(_repo, _commit.SHA, file.Path);
+                        var content = new StreamReader(contentStream).ReadToEnd();
                         if (content.StartsWith("version https://git-lfs.github.com/spec/", StringComparison.Ordinal))
                         {
                             var obj = new Models.RevisionLFSObject() { Object = new Models.LFSObject() };

src/ViewModels/CommitDetail.cs

@@ -101,13 +101,13 @@ public DiffContext(string repo, Models.DiffOption option, DiffContext previous =
                         var imgDiff = new Models.ImageDiff();
                         if (option.Revisions.Count == 2)
                         {
-                            imgDiff.Old = Commands.GetImageFileAsBitmap.Run(repo, option.Revisions[0], oldPath);
-                            imgDiff.New = Commands.GetImageFileAsBitmap.Run(repo, option.Revisions[1], oldPath);
+                            imgDiff.Old = BitmapFromRevisionFile(repo, option.Revisions[0], oldPath);
+                            imgDiff.New = BitmapFromRevisionFile(repo, option.Revisions[1], oldPath);
                         }
                         else
                         {
                             var fullPath = Path.Combine(repo, _option.Path);
-                            imgDiff.Old = Commands.GetImageFileAsBitmap.Run(repo, "HEAD", oldPath);
+                            imgDiff.Old = BitmapFromRevisionFile(repo, "HEAD", oldPath);
                             imgDiff.New = File.Exists(fullPath) ? new Bitmap(fullPath) : null;
                         }
                         rs = imgDiff;
@@ -163,6 +163,12 @@ public void OpenExternalMergeTool()
             Task.Run(() => Commands.MergeTool.OpenForDiff(_repo, exec, args, _option));
         }
 
+        private Bitmap BitmapFromRevisionFile(string repo, string revision, string file)
+        {
+            var stream = Commands.QueryFileContent.Run(repo, revision, file);
+            return stream != null ? new Bitmap(stream) : null;
+        }
+
         private static readonly HashSet<string> IMG_EXTS = new HashSet<string>()
         {
             ".ico", ".bmp", ".jpg", ".png", ".jpeg"