minimize temporary strings for better performance

VERSION

@@ -1 +1 @@
-2025.14
+2025.15

src/Converters/PathConverters.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.IO;
 
 using Avalonia.Data.Converters;
@@ -22,7 +22,7 @@ public static class PathConverters
                 var home = Environment.GetFolderPath(Environment.SpecialFolder.UserProfile);
                 var prefixLen = home.EndsWith('/') ? home.Length - 1 : home.Length;
                 if (v.StartsWith(home, StringComparison.Ordinal))
-                    return "~" + v.Substring(prefixLen);
+                    return $"~{v.Substring(prefixLen)}";
 
                 return v;
             });

src/Models/DiffResult.cs

@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.Text;
 using System.Text.RegularExpressions;
 
@@ -147,9 +148,10 @@ public TextDiffSelection MakeSelection(int startLine, int endLine, bool isCombin
         public void GenerateNewPatchFromSelection(Change change, string fileBlobGuid, TextDiffSelection selection, bool revert, string output)
         {
             var isTracked = !string.IsNullOrEmpty(fileBlobGuid);
-            var fileGuid = isTracked ? fileBlobGuid.Substring(0, 8) : "00000000";
 
-            var builder = new StringBuilder();
+            var fileGuid = isTracked ? fileBlobGuid.AsSpan().Slice(0, 8) : "00000000".AsSpan();
+
+            var builder = new StringBuilder(512);
             builder.Append("diff --git a/").Append(change.Path).Append(" b/").Append(change.Path).Append('\n');
             if (!revert && !isTracked)
                 builder.Append("new file mode 100644\n");

src/Models/Worktree.cs

@@ -1,4 +1,5 @@
-using CommunityToolkit.Mvvm.ComponentModel;
+using System;
+using CommunityToolkit.Mvvm.ComponentModel;
 
 namespace SourceGit.Models
 {
@@ -22,12 +23,12 @@ public string Name
             get
             {
                 if (IsDetached)
-                    return $"deteched HEAD at {Head.Substring(10)}";
+                    return $"deteched HEAD at {Head.AsSpan().Slice(10)}";
 
-                if (Branch.StartsWith("refs/heads/", System.StringComparison.Ordinal))
+                if (Branch.StartsWith("refs/heads/", StringComparison.Ordinal))
                     return Branch.Substring(11);
 
-                if (Branch.StartsWith("refs/remotes/", System.StringComparison.Ordinal))
+                if (Branch.StartsWith("refs/remotes/", StringComparison.Ordinal))
                     return Branch.Substring(13);
 
                 return Branch;

src/ViewModels/Archive.cs

@@ -1,4 +1,5 @@
-using System.ComponentModel.DataAnnotations;
+using System;
+using System.ComponentModel.DataAnnotations;
 using System.IO;
 using System.Threading.Tasks;
 
@@ -31,7 +32,7 @@ public Archive(Repository repo, Models.Commit commit)
         {
             _repo = repo;
             _revision = commit.SHA;
-            _saveFile = $"archive-{commit.SHA.Substring(0, 10)}.zip";
+            _saveFile = $"archive-{commit.SHA.AsSpan().Slice(0, 10)}.zip";
             BasedOn = commit;
         }
 

src/ViewModels/Blame.cs

@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.Threading.Tasks;
 
 using Avalonia.Threading;
@@ -30,7 +31,7 @@ public Blame(string repo, string file, string revision)
         {
             _repo = repo;
 
-            Title = $"{file} @ {revision.Substring(0, 10)}";
+            Title = $"{file} @ {revision.AsSpan().Slice(0, 10)}";
             Task.Run(() =>
             {
                 var result = new Commands.Blame(repo, file, revision).Result();

src/ViewModels/Launcher.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.IO;
 
 using Avalonia.Collections;
@@ -584,7 +584,7 @@ private void UpdateTitle()
                     var home = Environment.GetFolderPath(Environment.SpecialFolder.UserProfile);
                     var prefixLen = home.EndsWith('/') ? home.Length - 1 : home.Length;
                     if (path.StartsWith(home, StringComparison.Ordinal))
-                        path = "~" + path.Substring(prefixLen);
+                        path = $"~{path.AsSpan().Slice(prefixLen)}";
                 }
 
                 Title = $"[{workspace}] {name} ({path})";

src/Views/CommitSubjectPresenter.cs

@@ -47,7 +47,7 @@ public FontWeight FontWeight
             get => GetValue(FontWeightProperty);
             set => SetValue(FontWeightProperty, value);
         }
-        
+
         public static readonly StyledProperty<IBrush> InlineCodeBackgroundProperty =
             AvaloniaProperty.Register<CommitSubjectPresenter, IBrush>(nameof(InlineCodeBackground), Brushes.Transparent);
 

src/Views/Histories.axaml.cs

@@ -205,7 +205,7 @@ private void OnCommitListKeyDown(object sender, KeyEventArgs e)
                     foreach (var item in selected)
                     {
                         if (item is Models.Commit commit)
-                            builder.AppendLine($"{commit.SHA.Substring(0, 10)} - {commit.Subject}");
+                            builder.AppendLine($"{commit.SHA.AsSpan().Slice(0, 10)} - {commit.Subject}");
                     }
 
                     App.CopyText(builder.ToString());

src/Views/TextDiffView.axaml.cs

@@ -1047,7 +1047,8 @@ private void CopyWithoutIndicators()
                 // The first selected line (partial selection)
                 if (i == startIdx && startPosition.Column > 1)
                 {
-                    builder.AppendLine(line.Content.Substring(startPosition.Column - 1));
+                    builder.Append(line.Content.AsSpan().Slice(startPosition.Column - 1));
+                    builder.Append(Environment.NewLine);
                     continue;
                 }
 
@@ -1061,7 +1062,14 @@ private void CopyWithoutIndicators()
                 // For the last line (selection range is within original source)
                 if (i == endIdx)
                 {
-                    builder.Append(endPosition.Column - 1 < line.Content.Length ? line.Content.Substring(0, endPosition.Column - 1) : line.Content);
+                    if (endPosition.Column - 1 < line.Content.Length)
+                    {
+                        builder.Append(line.Content.AsSpan().Slice(0, endPosition.Column - 1));
+                    }
+                    else
+                    {
+                        builder.Append(line.Content);
+                    }
                     break;
                 }
 
@@ -1246,12 +1254,12 @@ protected override void OnDataContextChanged(EventArgs e)
             var textDiff = DataContext as Models.TextDiff;
             if (textDiff != null)
             {
-                var builder = new StringBuilder();
+                var builder = new StringBuilder(512);
                 foreach (var line in textDiff.Lines)
                 {
                     if (line.Content.Length > 10000)
                     {
-                        builder.Append(line.Content.Substring(0, 1000));
+                        builder.Append(line.Content.AsSpan().Slice(0, 1000));
                         builder.Append($"...({line.Content.Length - 1000} character trimmed)");
                     }
                     else