Option to use Flatpaks under Linux

src/components/settings-components/SettingsView.vue

@@ -299,6 +299,23 @@ let settingsList = [
         'fa-file-alt',
         () => emitInvoke('ShowDependencyStrings')
     ),
+    new SettingsRow(
+        'Other',
+        'Launch as Flatpak (Linux)',
+        'Launch Steam via flatpak',
+        async () => {
+            switch (settings.value.getContext().global.linuxUseFlatpak) {
+                case null:
+                    return 'Automatic';
+                case true:
+                    return 'Flatpak';
+                case false:
+                    return 'Native';
+            }
+        },
+        'fa-exchange-alt',
+        () => emitInvoke('ToggleLinuxUseFlatpak')
+    ),
 ];
 
 watch(search, () => {

src/pages/Manager.vue

@@ -338,6 +338,10 @@ function setFunkyMode(value: boolean) {
     settings.value.setFunkyMode(value);
 }
 
+function setLinuxUseFlatpak(value: boolean) {
+    settings.value.setLinuxUseFlatpak(value);
+}
+
 function browseDataFolder() {
     LinkProvider.instance.openLink('file://' + PathResolver.ROOT);
 }
@@ -508,6 +512,9 @@ async function handleSettingsCallbacks(invokedSetting: any) {
         case "ToggleFunkyMode":
             setFunkyMode(!settings.value.getContext().global.funkyModeEnabled);
             break;
+        case "ToggleLinuxUseFlatpak":
+            setLinuxUseFlatpak(!settings.value.getContext().global.linuxUseFlatpak);
+            break;
         case "SwitchTheme":
             toggleDarkTheme();
             document.documentElement.classList.toggle('html--dark', settings.value.getContext().global.darkTheme);

src/r2mm/launching/runners/linux/SteamGameRunner_Linux.ts

@@ -55,26 +55,51 @@ export default class SteamGameRunner_Linux extends GameRunnerProvider {
         if (args instanceof R2Error) {
             return args
         }
-        return this.start(game, args);
+        return this.start(game, args, profile.getProfilePath());
     }
 
     public async startVanilla(game: Game, profile: Profile): Promise<void | R2Error> {
         const instructions = await GameInstructions.getInstructionsForGame(game, profile);
-        return this.start(game, instructions.vanillaParameters);
+        return this.start(game, instructions.vanillaParameters, null);
     }
 
-    async start(game: Game, args: string): Promise<void | R2Error> {
+    async start(game: Game, args: string, profiledir: string | null): Promise<void | R2Error> {
 
         const settings = await ManagerSettings.getSingleton(game);
         const steamDir = await GameDirectoryResolverProvider.instance.getSteamDirectory();
         if(steamDir instanceof R2Error) {
             return steamDir;
         }
+        let as_flatpak = settings.getContext().global.linuxUseFlatpak;
+        if (as_flatpak === null) {
+            // Assume that if the path contains the flatpak directory we must want to use flatpak
+            as_flatpak = steamDir.includes("/com.valvesoftware.Steam/");
+        }
+
+        if (as_flatpak && profiledir) {
+            // Ensure we have permission to read our config dir
+            let visible = true;
+            const check_cmd = `flatpak run --command='sh' com.valvesoftware.Steam -c 'ls "${profiledir}"'`;
+            await ChildProcess.exec(check_cmd, undefined, (err: Error) => {
+                if (err) {
+                    visible = false;
+                }
+            });
+            if (!visible) {
+                throw new R2Error('Flatpak Permissions Error',
+                    `The directory "${profiledir}" is not visible from within the Flatpak container`,
+                    '`flatpak override com.valvesoftware.Steam --user --filesystem="${XDG_CONFIG_HOME:-$HOME/.config}/r2modmanPlus-local"` to grant access, then restart Steam.');
+            }
+        }
 
         LoggerProvider.instance.Log(LogSeverity.INFO, `Steam folder is: ${steamDir}`);
 
         try {
-            const cmd = `"${steamDir}/steam.sh" -applaunch ${game.activePlatform.storeIdentifier} ${args} ${settings.getContext().gameSpecific.launchParameters}`;
+            let cmd = `"${steamDir}/steam.sh" -applaunch ${game.activePlatform.storeIdentifier} ${args} ${settings.getContext().gameSpecific.launchParameters}`;
+            if (as_flatpak) {
+                cmd = `flatpak run com.valvesoftware.Steam ${cmd}`;
+            }
+
             LoggerProvider.instance.Log(LogSeverity.INFO, `Running command: ${cmd}`);
             await ChildProcess.exec(cmd);
         } catch(err) {

src/r2mm/manager/ManagerSettings.ts

@@ -98,6 +98,11 @@ export default class ManagerSettings {
         await this.save();
     }
 
+    public async setLinuxUseFlatpak(enabled: boolean) {
+        ManagerSettings.CONTEXT.global.linuxUseFlatpak = enabled;
+        await this.save();
+    }
+
     public async expandCards() {
         ManagerSettings.CONTEXT.global.expandedCards = true;
         await this.save();

src/r2mm/manager/SettingsDexieStore.ts

@@ -123,6 +123,7 @@ export default class SettingsDexieStore extends Dexie {
                 defaultStore: undefined,
                 gameSelectionViewMode: GameSelectionViewMode.CARD,
                 previewPanelWidth: 500,
+                linuxUseFlatpak: null,
             },
             gameSpecific: {
                 version: 2,
@@ -212,6 +213,7 @@ export interface ManagerSettingsInterfaceGlobal_V2 {
     defaultStore: Platform | undefined;
     gameSelectionViewMode: GameSelectionViewMode;
     previewPanelWidth: number;
+    linuxUseFlatpak: boolean | null;
 }
 
 /**