optimize<WorkingCopy>: do not re-diff when file not changed

src/Views/Widgets/Dashboard.xaml.cs

@@ -1,10 +1,8 @@
 using System;
 using System.Collections.Generic;
-using System.ComponentModel;
 using System.Diagnostics;
 using System.IO;
 using System.Linq;
-using System.Net.Sockets;
 using System.Threading.Tasks;
 using System.Windows;
 using System.Windows.Controls;
@@ -12,7 +10,6 @@ using System.Windows.Controls.Primitives;
 using System.Windows.Input;
 using System.Windows.Media;
 using System.Windows.Media.Animation;
-using System.Xml.Linq;
 
 namespace SourceGit.Views.Widgets {
 

src/Views/Widgets/DiffViewer.xaml

@@ -16,7 +16,7 @@
     </UserControl.Resources>
     
     <Border BorderBrush="{DynamicResource Brush.Border2}" BorderThickness="1">
-        <Grid>
+        <Grid x:Name="body">
             <Grid.RowDefinitions>
                 <RowDefinition Height="26"/>
                 <RowDefinition Height="*"/>

src/Views/Widgets/DiffViewer.xaml.cs

@@ -23,6 +23,7 @@ namespace SourceGit.Views.Widgets {
             public string OrgPath = null;
             public string ExtraArgs = "";
             public bool UseLFS = false;
+            public bool WCChanges = false;
         }
 
         private ulong seq = 0;
@@ -31,6 +32,7 @@ namespace SourceGit.Views.Widgets {
         private List<Models.TextChanges.Line> cachedTextChanges = null;
         private List<DataGrid> editors = new List<DataGrid>();
         private List<Rectangle> splitters = new List<Rectangle>();
+        private string lastWCFileId = "";
 
         public DiffViewer() {
             InitializeComponent();
@@ -51,6 +53,8 @@ namespace SourceGit.Views.Widgets {
             toolbar.Visibility = Visibility.Collapsed;
             noChange.Visibility = Visibility.Collapsed;
             sizeChange.Visibility = Visibility.Collapsed;
+            textDiff.Visibility = Visibility.Collapsed;
+            lastWCFileId = "";
             ClearCache();
 
             foreach (var e in editors) e.ItemsSource = null;
@@ -58,15 +62,27 @@ namespace SourceGit.Views.Widgets {
         }
 
         public void Diff(string repo, Option opt) {
-            seq++;
+            if (opt.WCChanges) {
+                var fileInfo = new System.IO.FileInfo(repo + "/" + opt.Path);
+                if (fileInfo.Exists) {
+                    var wcFileID = string.Format("{0}@{1}", opt.Path, fileInfo.LastWriteTime.ToFileTime());
+                    if (wcFileID == lastWCFileId) return;
+                    lastWCFileId = wcFileID;
+                } else {
+                    lastWCFileId = "";
+                }
+            } else {
+                lastWCFileId = "";
+            }
 
-            foreach (var e in editors) e.ItemsSource = null;
+            seq++;
-            foreach (var s in splitters) s.Visibility = Visibility.Hidden;
             ClearCache();
 
             mask.Visibility = Visibility.Collapsed;
             noChange.Visibility = Visibility.Collapsed;
             sizeChange.Visibility = Visibility.Collapsed;
+            toolbarOptions.Visibility = Visibility.Collapsed;
+            textDiff.Visibility = Visibility.Collapsed;
             toolbar.Visibility = Visibility.Visible;
             loading.Visibility = Visibility.Visible;
             loading.IsAnimating = true;
@@ -140,7 +156,6 @@ namespace SourceGit.Views.Widgets {
 
                 loading.Visibility = Visibility.Collapsed;
                 mask.Visibility = Visibility.Collapsed;
-                toolbarOptions.Visibility = Visibility.Collapsed;
                 sizeChange.Visibility = Visibility.Visible;
 
                 txtSizeChangeTitle.Text = App.Text("Diff.Binary");
@@ -159,7 +174,6 @@ namespace SourceGit.Views.Widgets {
 
                 loading.Visibility = Visibility.Collapsed;
                 mask.Visibility = Visibility.Collapsed;
-                toolbarOptions.Visibility = Visibility.Collapsed;
                 sizeChange.Visibility = Visibility.Visible;
 
                 txtSizeChangeTitle.Text = App.Text("Diff.LFS");
@@ -175,7 +189,6 @@ namespace SourceGit.Views.Widgets {
 
                 loading.Visibility = Visibility.Collapsed;
                 mask.Visibility = Visibility.Collapsed;
-                toolbarOptions.Visibility = Visibility.Collapsed;
                 noChange.Visibility = Visibility.Visible;
             });
         }
@@ -207,11 +220,12 @@ namespace SourceGit.Views.Widgets {
                 loading.Visibility = Visibility.Collapsed;
                 mask.Visibility = Visibility.Collapsed;
                 toolbarOptions.Visibility = Visibility.Visible;
+                textDiff.Visibility = Visibility.Visible;
 
                 var createEditor = editors.Count == 0;
                 var lineNumberWidth = CalcLineNumberColWidth(lastOldLine, lastNewLine);
-                var minWidth = textDiff.ActualWidth - lineNumberWidth * 2;
+                var minWidth = body.ActualWidth - lineNumberWidth * 2;
-                if (textDiff.ActualHeight < cachedTextChanges.Count * 16) minWidth -= 8;
+                if (body.ActualHeight - 26 < cachedTextChanges.Count * 16) minWidth -= 8;
 
                 DataGrid editor;
                 if (createEditor) {
@@ -272,11 +286,12 @@ namespace SourceGit.Views.Widgets {
                 loading.Visibility = Visibility.Collapsed;
                 mask.Visibility = Visibility.Collapsed;
                 toolbarOptions.Visibility = Visibility.Visible;
+                textDiff.Visibility = Visibility.Visible;
 
                 var createEditor = editors.Count == 0;
                 var lineNumberWidth = CalcLineNumberColWidth(lastOldLine, lastNewLine);
-                var minWidth = textDiff.ActualWidth / 2 - lineNumberWidth;
+                var minWidth = body.ActualWidth / 2 - lineNumberWidth;
-                if (textDiff.ActualHeight < newSideBlocks.Count * 16) minWidth -= 8;
+                if (body.ActualHeight - 26 < newSideBlocks.Count * 16) minWidth -= 8;
 
                 DataGrid oldEditor, newEditor;
                 if (createEditor) {
@@ -441,11 +456,11 @@ namespace SourceGit.Views.Widgets {
         private void OnTextDiffSizeChanged(object sender, SizeChangedEventArgs e) {
             if (editors.Count == 0) return;
 
-            var total = textDiff.ActualWidth / editors.Count;
+            var total = body.ActualWidth / editors.Count;
             for (int i = 0; i < editors.Count; i++) {
                 var editor = editors[i];
                 var minWidth = total - editor.NonFrozenColumnsViewportHorizontalOffset;
-                if (editor.Items.Count * 16 > textDiff.ActualHeight) minWidth -= 8;
+                if (editor.Items.Count * 16 > body.ActualHeight - 26) minWidth -= 8;
 
                 var lastColumn = editor.Columns.Count - 1;
                 editor.Columns[lastColumn].MinWidth = minWidth;

src/Views/Widgets/WorkingCopy.xaml.cs

@@ -53,16 +53,24 @@ namespace SourceGit.Views.Widgets {
                 btnCommitAndPush.Visibility = Visibility.Collapsed;
             }
 
-            var diffTarget = unstagedContainer.DiffTarget;
-            if (diffTarget == null) diffTarget = stagedContainer.DiffTarget;
-            if (diffTarget == null) {
             mergePanel.Visibility = Visibility.Collapsed;
-                diffViewer.Reset();
+
-            } else if (diffTarget.IsConflit) {
+            var diffTarget = unstagedContainer.DiffTarget;
+            if (diffTarget != null) {
+                if (diffTarget.IsConflit) {
                     mergePanel.Visibility = Visibility.Visible;
                     diffViewer.Reset();
                 } else {
-                mergePanel.Visibility = Visibility.Collapsed;
+                    diffViewer.Reload();
+                }
+
+                return;
+            }
+
+            diffTarget = stagedContainer.DiffTarget;
+            if (diffTarget == null) {
+                diffViewer.Reset();
+            } else {
                 diffViewer.Reload();
             }
         }
@@ -145,14 +153,16 @@ namespace SourceGit.Views.Widgets {
                         ExtraArgs = "--no-index",
                         Path = change.Path,
                         OrgPath = "/dev/null",
-                        UseLFS = isLFSEnabled
+                        UseLFS = isLFSEnabled,
+                        WCChanges = true,
                     });
                     break;
                 default:
                     diffViewer.Diff(repo.Path, new DiffViewer.Option() {
                         Path = change.Path,
                         OrgPath = change.OriginalPath,
-                        UseLFS = isLFSEnabled
+                        UseLFS = isLFSEnabled,
+                        WCChanges = true,
                     });
                     break;
                 }