Fix race conditions for theme import and config save

Author: t1m0thyj

src/AppContext.cs

@@ -126,6 +126,7 @@ private void OnApplicationExit(object sender, EventArgs e)
                 notifyIcon.Visible = false;
             }
 
+            JsonConfig.SaveConfig();
             ipcManager?.Dispose();
         }
     }

src/ImportDialog.cs

@@ -4,7 +4,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Drawing;
 using System.IO;
 using System.Threading.Tasks;
 using System.Windows.Forms;
@@ -90,8 +89,11 @@ private void UpdateTotalPercentage(int themePercentage)
 
         private void OnFormClosing(object sender, FormClosingEventArgs e)
         {
-            ThemeLoader.taskbarHandle = IntPtr.Zero;
             ThemeManager.importMode = false;
+            if (thumbnailsLoaded)
+            {
+                ThemeLoader.taskbarHandle = IntPtr.Zero;
+            }
         }
     }
 }

src/JsonConfig.cs

@@ -7,7 +7,6 @@
 using System;
 using System.ComponentModel;
 using System.IO;
-using System.Threading.Tasks;
 using System.Windows.Forms;
 
 namespace WinDynamicDesktop
@@ -59,6 +58,7 @@ class JsonConfig
         private static System.Timers.Timer autoSaveTimer;
         private static bool restartPending = false;
         private static bool unsavedChanges;
+        private static readonly object settingsFileLock = new object();
 
         public static AppConfig settings = new AppConfig();
         public static bool firstRun = !File.Exists("settings.json");
@@ -93,9 +93,8 @@ public static void LoadConfig()
             }
 
             unsavedChanges = false;
-            autoSaveTimer = new System.Timers.Timer();
+            autoSaveTimer = new System.Timers.Timer(1000);
             autoSaveTimer.AutoReset = false;
-            autoSaveTimer.Interval = 1000;
             ConfigMigrator.UpdateObsoleteSettings();
 
             settings.PropertyChanged += OnSettingsPropertyChanged;
@@ -108,48 +107,47 @@ public static void ReloadConfig()
             autoSaveTimer.Start();
         }
 
+        public static void SaveConfig()
+        {
+            if (!unsavedChanges)
+            {
+                return;
+            }
+
+            unsavedChanges = autoSaveTimer.Enabled = false;
+            string jsonText = JsonConvert.SerializeObject(settings, Formatting.Indented);
+            lock (settingsFileLock)
+            {
+                File.WriteAllText("settings.json.tmp", jsonText);
+                File.Move("settings.json.tmp", "settings.json", true);
+            }
+        }
+
         public static bool IsNullOrEmpty(Array array)
         {
             return (array == null || array.Length == 0);
         }
 
         private static void OnSettingsPropertyChanged(object sender, EventArgs e)
         {
-            unsavedChanges = true;
-            autoSaveTimer.Start();
+            unsavedChanges = autoSaveTimer.Enabled = true;
         }
 
-        private static async void OnAutoSaveTimerElapsed(object sender, EventArgs e)
+        private static void OnAutoSaveTimerElapsed(object sender, EventArgs e)
         {
             if (!restartPending && !unsavedChanges)
             {
                 return;
             }
 
-            if (unsavedChanges)
-            {
-                unsavedChanges = false;
-                autoSaveTimer.Elapsed -= OnAutoSaveTimerElapsed;
-
-                await Task.Run(() =>
-                {
-                    string jsonText = JsonConvert.SerializeObject(settings, Formatting.Indented);
-                    File.WriteAllText("settings.json.tmp", jsonText);
-                    File.Move("settings.json.tmp", "settings.json", true);
-                });
-            }
+            SaveConfig();
 
             if (restartPending)
             {
                 restartPending = false;
                 System.Diagnostics.Process.Start(Application.ExecutablePath);
                 Application.Exit();
             }
-            else
-            {
-                autoSaveTimer.Elapsed += OnAutoSaveTimerElapsed;
-                autoSaveTimer.Start();
-            }
         }
     }
 }

src/ThemeDialog.cs

@@ -140,38 +140,48 @@ private void LoadThemes(List<ThemeConfig> themes, string activeTheme = null, str
 
             foreach (ThemeConfig theme in themes.ToList())
             {
-                try
+                ListViewItem tempItem = this.Invoke(new Func<ListViewItem>(() =>
                 {
-                    using (Image thumbnailImage = ThemeThumbLoader.GetThumbnailImage(theme, thumbnailSize, true))
+                    string itemText = ThemeManager.GetThemeName(theme);
+                    if (JsonConfig.settings.favoriteThemes != null &&
+                        JsonConfig.settings.favoriteThemes.Contains(theme.themeId))
                     {
-                        this.Invoke(new Action(() =>
+                        itemText = "★ " + itemText;
+                    }
+                    ListViewItem newItem = listView1.Items.Add(itemText);
+                    newItem.Tag = theme.themeId;
+
+                    if (activeTheme != null && activeTheme == theme.themeId)
+                    {
+                        newItem.Font = new Font(newItem.Font, FontStyle.Bold);
+                    }
+                    if (focusTheme == null || focusTheme == theme.themeId)
+                    {
+                        focusedItem = newItem;
+                    }
+
+                    return newItem;
+                }));
+
+                this.BeginInvoke(new Action<ListViewItem>((newItem) =>
+                {
+                    try
+                    {
+                        using (Image thumbnailImage = ThemeThumbLoader.GetThumbnailImage(theme, thumbnailSize, true))
                         {
                             listView1.LargeImageList.Images.Add(thumbnailImage);
-                            string itemText = ThemeManager.GetThemeName(theme);
-                            if (JsonConfig.settings.favoriteThemes != null &&
-                                JsonConfig.settings.favoriteThemes.Contains(theme.themeId))
-                            {
-                                itemText = "★ " + itemText;
-                            }
-                            ListViewItem newItem = listView1.Items.Add(itemText,
-                                listView1.LargeImageList.Images.Count - 1);
-                            newItem.Tag = theme.themeId;
-
-                            if (activeTheme != null && activeTheme == theme.themeId)
-                            {
-                                newItem.Font = new Font(newItem.Font, FontStyle.Bold);
-                            }
-                            if (focusTheme == null || focusTheme == theme.themeId)
-                            {
-                                focusedItem = newItem;
-                            }
-                        }));
+                            newItem.ImageIndex = listView1.LargeImageList.Images.Count - 1;
+                        }
                     }
-                }
-                catch (OutOfMemoryException)
-                {
-                    ThemeLoader.HandleError(new FailedToCreateThumbnail(theme.themeId));
-                }
+                    catch (OutOfMemoryException)
+                    {
+                        ThemeLoader.HandleError(new FailedToCreateThumbnail(theme.themeId));
+                        if (ThemeManager.themeSettings.Find(t => t.themeId == theme.themeId) == null)
+                        {
+                            listView1.Items.RemoveAt(newItem.Index);
+                        }
+                    }
+                }), tempItem);
             }
 
             this.Invoke(new Action(() =>