Refactor code to avoid nulls (#206)

* Ensure potential nulls have a fallback value & add/remove null checks

* Refactor update check code to avoid nulls

* Refactor ProfileManager exception handling to avoid nulls

* Refactor a few more various classes and fix nulls in ContextInfo

* Force c#7 everywhere and revert usage of newer features from cherry-picked commits

* Remove unused #pragma declaration

Core/Handling/ContextMenuBase.cs

@@ -132,7 +132,7 @@ void ViewImage(string path){
                     }
 
                     string url = LastLink.GetMediaSource(parameters);
-                    string file = Path.Combine(BrowserCache.CacheFolder, TwitterUtils.GetImageFileName(url));
+                    string file = Path.Combine(BrowserCache.CacheFolder, TwitterUtils.GetImageFileName(url) ?? Path.GetRandomFileName());
 
                     if (File.Exists(file)){
                         ViewImage(file);
@@ -187,7 +187,7 @@ protected void OpenBrowser(Control control, string url){
         }
 
         protected void SetClipboardText(Control control, string text){
-            control.InvokeAsyncSafe(() => WindowsUtils.SetClipboard(text, TextDataFormat.UnicodeText));
+            control.InvokeAsyncSafe(() => WindowsUtils.SetClipboard(text ?? string.Empty, TextDataFormat.UnicodeText));
         }
         
         protected static void AddDebugMenuItems(IMenuModel model){

Core/Management/ContextInfo.cs

@@ -11,7 +11,12 @@ public ContextInfo(){
         }
         
         public void SetLink(string type, string url){
-            Link = new LinkInfo(string.IsNullOrEmpty(url) ? null : type, url);
+            if (string.IsNullOrEmpty(url)){
+                Link = new LinkInfo();
+            }
+            else{
+                Link = new LinkInfo(type, url);
+            }
         }
 
         public void SetChirp(string tweetUrl, string quoteUrl, string chirpAuthors, string chirpImages){

Core/Management/ProfileManager.cs

@@ -23,7 +23,6 @@ public enum Items{
         }
 
         public bool IsRestarting { get; private set; }
-        public Exception LastException { get; private set; }
 
         private readonly string file;
         private readonly PluginManager plugins;
@@ -67,7 +66,7 @@ public bool Export(Items items){
 
                 return true;
             }catch(Exception e){
-                LastException = e;
+                Program.Reporter.HandleException("Profile Export Error", "An exception happened while exporting TweetDuck profile.", true, e);
                 return false;
             }
         }
@@ -100,8 +99,7 @@ public Items FindImportItems(){
                         }
                     }
                 }
-            }catch(Exception e){
+            }catch(Exception){
-                LastException = e;
                 items = Items.None;
             }
 
@@ -164,12 +162,12 @@ public bool Import(Items items){
                 }
 
                 if (missingPlugins.Count > 0){
-                    FormMessage.Information("Importing TweetDuck Profile", "Detected missing plugins when importing plugin data:\n"+string.Join("\n", missingPlugins), FormMessage.OK);
+                    FormMessage.Information("Profile Import", "Detected missing plugins when importing plugin data:\n"+string.Join("\n", missingPlugins), FormMessage.OK);
                 }
 
                 return true;
             }catch(Exception e){
-                LastException = e;
+                Program.Reporter.HandleException("Profile Import Error", "An exception happened while importing TweetDuck profile.", true, e);
                 return false;
             }
         }
@@ -199,15 +197,23 @@ public static void DeleteCookies(){
         }
 
         private static IEnumerable<PathInfo> EnumerateFilesRelative(string root){
-            return Directory.Exists(root) ? Directory.EnumerateFiles(root, "*.*", SearchOption.AllDirectories).Select(fullPath => new PathInfo{
+            if (Directory.Exists(root)){
-                Full = fullPath,
+                int rootLength = root.Length;
-                Relative = fullPath.Substring(root.Length).TrimStart(Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar) // strip leading separator character
+                return Directory.EnumerateFiles(root, "*.*", SearchOption.AllDirectories).Select(fullPath => new PathInfo(fullPath, rootLength));
-            }) : Enumerable.Empty<PathInfo>();
+            }
+            else{
+                return Enumerable.Empty<PathInfo>();
+            }
         }
 
         private sealed class PathInfo{
-            public string Full { get; set; }
+            public string Full { get; }
-            public string Relative { get; set; }
+            public string Relative { get; }
+
+            public PathInfo(string fullPath, int rootLength){
+                this.Full = fullPath;
+                this.Relative = fullPath.Substring(rootLength).TrimStart(Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar); // strip leading separator character
+            }
         }
     }
 

Core/Management/VideoPlayer.cs

@@ -14,8 +14,6 @@ sealed class VideoPlayer : IDisposable{
         public event EventHandler ProcessExited;
 
         private readonly FormBrowser owner;
-        private string lastUrl;
-        private string lastUsername;
 
         private Instance currentInstance;
         private bool isClosing;
@@ -30,9 +28,6 @@ public void Launch(string url, string username){
                 Destroy();
                 isClosing = false;
             }
-
-            lastUrl = url;
-            lastUsername = username;
             
             try{
                 DuplexPipe.Server pipe = DuplexPipe.CreateServer();
@@ -46,7 +41,7 @@ public void Launch(string url, string username){
                     UseShellExecute = false,
                     RedirectStandardOutput = true
                 })) != null){
-                    currentInstance = new Instance(process, pipe);
+                    currentInstance = new Instance(process, pipe, url, username);
 
                     process.EnableRaisingEvents = true;
                     process.Exited += process_Exited;
@@ -81,9 +76,9 @@ private void pipe_DataIn(object sender, DuplexPipe.PipeReadEventArgs e){
                         break;
 
                     case "download":
-                        if (!string.IsNullOrEmpty(lastUrl)){
+                        if (currentInstance != null){
                             owner.AnalyticsFile.DownloadedVideos.Trigger();
-                            TwitterUtils.DownloadVideo(lastUrl, lastUsername);
+                            TwitterUtils.DownloadVideo(currentInstance.Url, currentInstance.Username);
                         }
 
                         break;
@@ -147,6 +142,7 @@ private void process_Exited(object sender, EventArgs e){
             }
 
             int exitCode = currentInstance.Process.ExitCode;
+            string url = currentInstance.Url;
 
             currentInstance.Dispose();
             currentInstance = null;
@@ -154,14 +150,14 @@ private void process_Exited(object sender, EventArgs e){
             switch(exitCode){
                 case 3: // CODE_LAUNCH_FAIL
                     if (FormMessage.Error("Video Playback Error", "Error launching video player, this may be caused by missing Windows Media Player. Do you want to open the video in your browser?", FormMessage.Yes, FormMessage.No)){
-                        BrowserUtils.OpenExternalBrowser(lastUrl);
+                        BrowserUtils.OpenExternalBrowser(url);
                     }
 
                     break;
 
                 case 4: // CODE_MEDIA_ERROR
                     if (FormMessage.Error("Video Playback Error", "The video could not be loaded, most likely due to unknown format. Do you want to open the video in your browser?", FormMessage.Yes, FormMessage.No)){
-                        BrowserUtils.OpenExternalBrowser(lastUrl);
+                        BrowserUtils.OpenExternalBrowser(url);
                     }
 
                     break;
@@ -185,9 +181,14 @@ public bool Running{
             public Process Process { get; }
             public DuplexPipe.Server Pipe { get; }
 
-            public Instance(Process process, DuplexPipe.Server pipe){
+            public string Url { get; }
+            public string Username { get; }
+
+            public Instance(Process process, DuplexPipe.Server pipe, string url, string username){
                 this.Process = process;
                 this.Pipe = pipe;
+                this.Url = url;
+                this.Username = username;
             }
 
             public void KillAndDispose(){

Core/Notification/Example/FormNotificationExample.cs

@@ -24,7 +24,7 @@ protected override FormBorderStyle NotificationBorderStyle{
         private readonly TweetNotification exampleNotification;
 
         public FormNotificationExample(FormBrowser owner, PluginManager pluginManager) : base(owner, pluginManager, false){
-            string exampleTweetHTML = ScriptLoader.LoadResource("pages/example.html", true).Replace("{avatar}", TweetNotification.AppLogo.Url);
+            string exampleTweetHTML = ScriptLoader.LoadResource("pages/example.html", true)?.Replace("{avatar}", TweetNotification.AppLogo.Url) ?? string.Empty;
 
             #if DEBUG
             exampleTweetHTML = exampleTweetHTML.Replace("</p>", @"</p><div style='margin-top:256px'>Scrollbar test padding...</div>");

Core/Notification/FormNotificationBase.cs

@@ -217,7 +217,9 @@ protected virtual void UpdateTitle(){
         }
 
         public void ShowTweetDetail(){
-            owner.ShowTweetDetail(currentNotification.ColumnId, currentNotification.ChirpId, currentNotification.TweetUrl);
+            if (currentNotification != null){
+                owner.ShowTweetDetail(currentNotification.ColumnId, currentNotification.ChirpId, currentNotification.TweetUrl);
+            }
         }
 
         public void MoveToVisibleLocation(){

Core/Notification/TweetNotification.cs

@@ -8,7 +8,7 @@
 namespace TweetDuck.Core.Notification{
     sealed class TweetNotification{
         private const string DefaultHeadLayout = @"<html id='tduck' class='os-windows txt-size--14' data-td-font='medium' data-td-theme='dark'><head><meta charset='utf-8'><meta http-equiv='X-UA-Compatible' content='chrome=1'><link rel='stylesheet' href='https://ton.twimg.com/tweetdeck-web/web/css/font.5ef884f9f9.css'><link rel='stylesheet' href='https://ton.twimg.com/tweetdeck-web/web/css/app-dark.5631e0dd42.css'><style type='text/css'>body{background:#222426}</style>";
-        private static readonly string CustomCSS = ScriptLoader.LoadResource("styles/notification.css");
+        private static readonly string CustomCSS = ScriptLoader.LoadResource("styles/notification.css") ?? string.Empty;
         public static readonly ResourceLink AppLogo = new ResourceLink("https://ton.twimg.com/tduck/avatar", ResourceHandler.FromByteArray(Properties.Resources.avatar, "image/png"));
 
         public static TweetNotification Example(string html, int characters){

Core/Other/Analytics/AnalyticsFile.cs

@@ -21,7 +21,7 @@ static AnalyticsFile(){
             });
         }
 
-        public static readonly AnalyticsFile Dummy = new AnalyticsFile(null);
+        public static readonly AnalyticsFile Dummy = new AnalyticsFile();
 
         // STATE PROPERTIES
         
@@ -67,6 +67,10 @@ private AnalyticsFile(string file){
             this.file = file;
         }
 
+        private AnalyticsFile(){
+            this.file = null;
+        }
+
         private void SetupProperties(){
             foreach(Counter counter in GetType().GetProperties(BindingFlags.Instance | BindingFlags.Public).Where(prop => prop.PropertyType == typeof(Counter)).Select(prop => (Counter)prop.GetValue(this))){
                 counter.SetOwner(this);

Core/Other/FormGuide.cs

@@ -58,11 +58,8 @@ private FormGuide(string url, FormBrowser owner){
             InitializeComponent();
 
             Text = Program.BrandName+" Guide";
-
+            Size = new Size(owner.Size.Width*3/4, owner.Size.Height*3/4);
-            if (owner != null){
+            VisibleChanged += (sender, args) => this.MoveToCenter(owner);
-                Size = new Size(owner.Size.Width*3/4, owner.Size.Height*3/4);
-                VisibleChanged += (sender, args) => this.MoveToCenter(owner);
-            }
             
             this.browser = new ChromiumWebBrowser(url){
                 MenuHandler = new ContextMenuGuide(owner),

Core/Other/Settings/Dialogs/DialogSettingsManage.cs

@@ -164,9 +164,6 @@ private void btnContinue_Click(object sender, EventArgs e){
                             ShouldReloadBrowser = true;
                         }
                     }
-                    else{
-                        Program.Reporter.HandleException("Profile Import Error", "An exception happened while importing TweetDuck profile.", true, importManager.LastException);
-                    }
                     
                     DialogResult = DialogResult.OK;
                     Close();
@@ -191,12 +188,8 @@ private void btnContinue_Click(object sender, EventArgs e){
 
                     Program.UserConfig.Save();
                     Program.SystemConfig.Save();
-
+                    
-                    ProfileManager manager = new ProfileManager(file, plugins);
+                    new ProfileManager(file, plugins).Export(SelectedItems);
-
-                    if (!manager.Export(SelectedItems)){
-                        Program.Reporter.HandleException("Profile Export Error", "An exception happened while exporting TweetDuck profile.", true, manager.LastException);
-                    }
 
                     DialogResult = DialogResult.OK;
                     Close();

Core/Other/Settings/TabSettingsGeneral.cs

@@ -170,7 +170,7 @@ private void btnCheckUpdates_Click(object sender, EventArgs e){
             }
         }
 
-        private void updates_CheckFinished(object sender, UpdateEventArgs e){
+        private void updates_CheckFinished(object sender, UpdateCheckEventArgs e){
             this.InvokeAsyncSafe(() => {
                 if (e.EventId == updateCheckEventId){
                     btnCheckUpdates.Enabled = true;

Core/Other/Settings/TabSettingsLocales.cs

@@ -42,12 +42,12 @@ private void checkSpellCheck_CheckedChanged(object sender, EventArgs e){
         }
 
         private void comboBoxSpellCheckLanguage_SelectedValueChanged(object sender, EventArgs e){
-            Config.SpellCheckLanguage = (comboBoxSpellCheckLanguage.SelectedItem as LocaleUtils.Item)?.Code;
+            Config.SpellCheckLanguage = (comboBoxSpellCheckLanguage.SelectedItem as LocaleUtils.Item)?.Code ?? "en-US";
             PromptRestart();
         }
 
         private void comboBoxTranslationTarget_SelectedValueChanged(object sender, EventArgs e){
-            Config.TranslationTarget = (comboBoxTranslationTarget.SelectedItem as LocaleUtils.Item)?.Code;
+            Config.TranslationTarget = (comboBoxTranslationTarget.SelectedItem as LocaleUtils.Item)?.Code ?? "en";
         }
     }
 }

Core/TweetDeckBrowser.cs

@@ -211,7 +211,7 @@ public void UpdateProperties(){
         }
 
         public void InjectBrowserCSS(){
-            browser.ExecuteScriptAsync("TDGF_injectBrowserCSS", ScriptLoader.LoadResource("styles/browser.css").TrimEnd());
+            browser.ExecuteScriptAsync("TDGF_injectBrowserCSS", ScriptLoader.LoadResource("styles/browser.css")?.TrimEnd() ?? string.Empty);
         }
 
         public void ReinjectCustomCSS(string css){

Plugins/Controls/PluginControl.cs

@@ -36,7 +36,7 @@ public PluginControl(PluginManager pluginManager, Plugin plugin) : this(){
                 labelDescription.Visible = false;
             }
 
-            panelDescription_Resize(panelDescription, null);
+            panelDescription_Resize(panelDescription, EventArgs.Empty);
         }
 
         private void panelDescription_Resize(object sender, EventArgs e){

Program.cs

@@ -151,10 +151,9 @@ private static void Main(){
 
             Application.ApplicationExit += (sender, args) => ExitCleanup();
 
-            UpdaterSettings updaterSettings = new UpdaterSettings{
+            UpdaterSettings updaterSettings = new UpdaterSettings(InstallerPath){
                 AllowPreReleases = Arguments.HasFlag(Arguments.ArgDebugUpdates),
-                DismissedUpdate = UserConfig.DismissedUpdate,
+                DismissedUpdate = UserConfig.DismissedUpdate
-                InstallerDownloadFolder = InstallerPath
             };
 
             FormBrowser mainForm = new FormBrowser(updaterSettings);

TweetDuck.csproj

@@ -291,6 +291,7 @@
       <DependentUpon>Resources.resx</DependentUpon>
     </Compile>
     <Compile Include="Reporter.cs" />
+    <Compile Include="Updates\Events\UpdateCheckEventArgs.cs" />
     <Compile Include="Updates\FormUpdateDownload.cs">
       <SubType>Form</SubType>
     </Compile>
@@ -312,7 +313,7 @@
     <Compile Include="Program.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="Resources\ScriptLoader.cs" />
-    <Compile Include="Updates\UpdateEventArgs.cs" />
+    <Compile Include="Updates\Events\UpdateEventArgs.cs" />
     <Compile Include="Updates\UpdaterSettings.cs" />
   </ItemGroup>
   <ItemGroup>

Updates/Events/UpdateCheckEventArgs.cs

@@ -0,0 +1,13 @@
+using System;
+
+namespace TweetDuck.Updates{
+    sealed class UpdateCheckEventArgs : EventArgs{
+        public int EventId { get; }
+        public bool IsUpdateAvailable { get; }
+
+        public UpdateCheckEventArgs(int eventId, bool isUpdateAvailable){
+            this.EventId = eventId;
+            this.IsUpdateAvailable = isUpdateAvailable;
+        }
+    }
+}

Updates/Events/UpdateEventArgs.cs

@@ -0,0 +1,11 @@
+using System;
+
+namespace TweetDuck.Updates{
+    sealed class UpdateEventArgs : EventArgs{
+        public UpdateInfo UpdateInfo { get; }
+        
+        public UpdateEventArgs(UpdateInfo updateInfo){
+            this.UpdateInfo = updateInfo;
+        }
+    }
+}

Updates/UpdateEventArgs.cs

@@ -1,20 +0,0 @@
-using System;
-
-namespace TweetDuck.Updates{
-    sealed class UpdateEventArgs : EventArgs{
-        public int EventId { get; }
-        public UpdateInfo UpdateInfo { get; }
-
-        public bool IsUpdateAvailable => UpdateInfo != null;
-
-        public UpdateEventArgs(int eventId, UpdateInfo updateInfo){
-            this.EventId = eventId;
-            this.UpdateInfo = updateInfo;
-        }
-
-        public UpdateEventArgs(UpdateInfo updateInfo){
-            this.EventId = updateInfo.EventId;
-            this.UpdateInfo = updateInfo;
-        }
-    }
-}

Updates/UpdateHandler.cs

@@ -16,7 +16,7 @@ sealed class UpdateHandler{
 
         public event EventHandler<UpdateEventArgs> UpdateAccepted;
         public event EventHandler<UpdateEventArgs> UpdateDismissed;
-        public event EventHandler<UpdateEventArgs> CheckFinished;
+        public event EventHandler<UpdateCheckEventArgs> CheckFinished;
 
         private ushort lastEventId;
         private UpdateInfo lastUpdateInfo;
@@ -93,7 +93,7 @@ private void TriggerUpdateDismissedEvent(UpdateEventArgs args){
             UpdateDismissed?.Invoke(this, args);
         }
 
-        private void TriggerCheckFinishedEvent(UpdateEventArgs args){
+        private void TriggerCheckFinishedEvent(UpdateCheckEventArgs args){
             CheckFinished?.Invoke(this, args);
         }
 
@@ -114,8 +114,8 @@ public void OnUpdateCheckFinished(int eventId, string versionTag, string downloa
                     owner.lastUpdateInfo = new UpdateInfo(owner.settings, eventId, versionTag, downloadUrl);
                     owner.lastUpdateInfo.BeginSilentDownload();
                 }
-
+                
-                owner.TriggerCheckFinishedEvent(new UpdateEventArgs(eventId, owner.lastUpdateInfo));
+                owner.TriggerCheckFinishedEvent(new UpdateCheckEventArgs(eventId, owner.lastUpdateInfo != null));
             }
 
             public void OnUpdateAccepted(){

Updates/UpdaterSettings.cs

@@ -1,7 +1,12 @@
 namespace TweetDuck.Updates{
     sealed class UpdaterSettings{
+        public string InstallerDownloadFolder { get; }
+
         public bool AllowPreReleases { get; set; }
         public string DismissedUpdate { get; set; }
-        public string InstallerDownloadFolder { get; set; }
+
+        public UpdaterSettings(string installerDownloadFolder){
+            this.InstallerDownloadFolder = installerDownloadFolder;
+        }
     }
 }

lib/TweetLib.Communication/TweetLib.Communication.csproj

@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
   <PropertyGroup>
@@ -20,6 +20,7 @@
     <PlatformTarget>x86</PlatformTarget>
     <ErrorReport>prompt</ErrorReport>
     <CodeAnalysisRuleSet>MinimumRecommendedRules.ruleset</CodeAnalysisRuleSet>
+    <LangVersion>7</LangVersion>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Release|x86'">
     <OutputPath>bin\x86\Release\</OutputPath>

subprocess/TweetDuck.Browser.csproj

@@ -15,6 +15,7 @@
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Debug|x86'">
     <PlatformTarget>x86</PlatformTarget>
     <OutputPath>bin\x86\Debug\</OutputPath>
+    <LangVersion>7</LangVersion>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Release|x86'">
     <PlatformTarget>x86</PlatformTarget>

tests/UnitTests.csproj

@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="12.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
@@ -22,6 +22,7 @@
     <PlatformTarget>x86</PlatformTarget>
     <OutputPath>bin\x86\Debug\</OutputPath>
     <Prefer32Bit>false</Prefer32Bit>
+    <LangVersion>7</LangVersion>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Release|x86'">
     <PlatformTarget>x86</PlatformTarget>

video/TweetDuck.Video.csproj

@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
   <PropertyGroup>
@@ -22,6 +22,7 @@
     <ErrorReport>prompt</ErrorReport>
     <CodeAnalysisRuleSet>MinimumRecommendedRules.ruleset</CodeAnalysisRuleSet>
     <Prefer32Bit>true</Prefer32Bit>
+    <LangVersion>7</LangVersion>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Release|x86'">
     <OutputPath>bin\x86\Release\</OutputPath>