Implement warn about opening external links option

osu.Game/Configuration/OsuConfigManager.cs

@@ -42,6 +42,8 @@ protected override void InitialiseDefaults()
                 if (!val) Set(OsuSetting.SavePassword, false);
             };
 
+            Set(OsuSetting.WarnAboutOpeningExternalLink, true);
+
             // Audio
             Set(OsuSetting.VolumeInactive, 0.25, 0, 1, 0.01);
 
@@ -148,6 +150,7 @@ public enum OsuSetting
         BeatmapSkins,
         BeatmapHitsounds,
         IncreaseFirstObjectVisibility,
-        ScoreDisplayMode
+        ScoreDisplayMode,
+        WarnAboutOpeningExternalLink
     }
 }

osu.Game/Graphics/Containers/LinkFlowContainer.cs

@@ -7,7 +7,9 @@
 using osu.Framework.Allocation;
 using osu.Framework.Graphics.Sprites;
 using System.Collections.Generic;
+using osu.Framework.Configuration;
 using osu.Framework.Platform;
+using osu.Game.Configuration;
 using osu.Game.Overlays;
 using osu.Game.Overlays.Chat;
 using osu.Game.Overlays.Notifications;
@@ -25,16 +27,20 @@ public LinkFlowContainer(Action<SpriteText> defaultCreationParameters = null)
 
         private Action showNotImplementedError;
         private GameHost host;
+
         private DialogOverlay dialogOverlay;
+        private Bindable<bool> warnAboutOpeningExternal;
 
         [BackgroundDependencyLoader(true)]
-        private void load(OsuGame game, NotificationOverlay notifications, GameHost host, DialogOverlay dialogOverlay)
+        private void load(OsuGame game, NotificationOverlay notifications, GameHost host, DialogOverlay dialogOverlay, OsuConfigManager config)
         {
             // will be null in tests
             this.game = game;
             this.host = host;
             this.dialogOverlay = dialogOverlay;
 
+            warnAboutOpeningExternal = config.GetBindable<bool>(OsuSetting.WarnAboutOpeningExternalLink);
+
             showNotImplementedError = () => notifications?.Post(new SimpleNotification
             {
                 Text = @"This link type is not yet supported!",
@@ -91,7 +97,11 @@ public void AddLink(string text, string url, LinkAction linkType = LinkAction.Ex
                             showNotImplementedError?.Invoke();
                             break;
                         case LinkAction.External:
-                            dialogOverlay.Push(new ExternalLinkDialog(url, () => host.OpenUrlExternally(url)));
+                            void externalAction() => host.OpenUrlExternally(url);
+                            if (warnAboutOpeningExternal)
+                                dialogOverlay.Push(new ExternalLinkDialog(url, externalAction));
+                            else
+                                externalAction();
                             break;
                         case LinkAction.OpenUserProfile:
                             if (long.TryParse(linkArgument, out long userId))

osu.Game/Overlays/Settings/Sections/Online/WebSettings.cs

@@ -0,0 +1,27 @@
+// Copyright (c) 2007-2018 ppy Pty Ltd <contact@ppy.sh>.
+// Licensed under the MIT Licence - https://raw.githubusercontent.com/ppy/osu/master/LICENCE
+
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Game.Configuration;
+
+namespace osu.Game.Overlays.Settings.Sections.Online
+{
+    public class WebSettings : SettingsSubsection
+    {
+        protected override string Header => "Web";
+
+        [BackgroundDependencyLoader]
+        private void load(OsuConfigManager config)
+        {
+            Children = new Drawable[]
+            {
+                new SettingsCheckbox
+                {
+                    LabelText = "Warn about opening external links",
+                    Bindable = config.GetBindable<bool>(OsuSetting.WarnAboutOpeningExternalLink)
+                },
+            };
+        }
+    }
+}

osu.Game/Overlays/Settings/Sections/OnlineSection.cs

@@ -3,6 +3,7 @@
 
 using osu.Framework.Graphics;
 using osu.Game.Graphics;
+using osu.Game.Overlays.Settings.Sections.Online;
 
 namespace osu.Game.Overlays.Settings.Sections
 {
@@ -15,6 +16,7 @@ public OnlineSection()
         {
             Children = new Drawable[]
             {
+                new WebSettings()
             };
         }
     }