Detect Flatpak permission errors on drag and drop (#1004)

src-main/l10n/en.json

@@ -458,5 +458,17 @@
   "rich-presence.untitled": {
     "string": "Untitled Project",
     "developer_comment": "Appears in Discord rich presence when the current project doesn't have a name."
+  },
+  "file-access.window-title": {
+    "string": "Can't Access Files",
+    "developer_comment": "Title of window that appears when user tries to drag & drop a file that the app can't access because of a security sandbox."
+  },
+  "file-access.flatpak": {
+    "string": "The Flatpak sandbox may be preventing {APP_NAME} from accessing files that you tried to drag and drop:",
+    "developer_comment": "Part of window that appears when user tries to drag & drop a file that the app can't access. Followed by list of paths. Leave 'Flatpak' in English."
+  },
+  "file-access.how-to-fix": {
+    "string": "Use the in-app file picker instead, or run the following command in a terminal and restart the app to grant access to the files:",
+    "developer_comment": "Part of window that appears when user tries to drag & drop a file that the app can't access."
   }
 }

src-main/protocols.js

@@ -52,6 +52,9 @@ const FILE_SCHEMES = {
   },
   'tw-security-prompt': {
     root: path.resolve(__dirname, '../src-renderer/security-prompt'),
+  },
+  'tw-file-access': {
+    root: path.resolve(__dirname, '../src-renderer/file-access'),
   }
 };
 

src-main/windows/editor.js

@@ -15,6 +15,7 @@ const prompts = require('../prompts');
 const settings = require('../settings');
 const privilegedFetch = require('../fetch');
 const RichPresence = require('../rich-presence.js');
+const FileAccessWindow = require('./file-access-window.js');
 
 const TYPE_FILE = 'file';
 const TYPE_URL = 'url';
@@ -508,6 +509,10 @@ class EditorWindow extends ProjectRunningWindow {
       };
     });
 
+    ipc.handle('check-drag-and-drop-path', (event, filePath) => {
+      FileAccessWindow.check(filePath);
+    });
+
     /**
      * Refers to the full screen button in the editor, not the OS-level fullscreen through
      * F11/Alt+Enter (Windows, Linux) or buttons provided by the OS (macOS).

src-main/windows/file-access-window.js

@@ -0,0 +1,101 @@
+const fsPromises = require('fs/promises');
+const pathUtil = require('path');
+const {getPlatform} = require('../platform');
+const AbstractWindow = require('./abstract');
+const {translate, getLocale, getStrings} = require('../l10n');
+const {APP_NAME} = require('../brand');
+
+/**
+ * @param {string} path
+ * @returns {Promise<boolean>} Promise that resolves to true if access seems to be missing.
+ */
+const missingFileAccess = async (path) => {
+  // Sanity check.
+  if (!pathUtil.isAbsolute(path)) {
+    return false;
+  }
+
+  try {
+    await fsPromises.stat(path);
+  } catch (e) {
+    if (e.code === 'ENOENT') {
+      return true;
+    }
+  }
+
+  // We were able to access the file, or the stat failed for a reason other than it not existing.
+  // Asking for more permission won't fix this.
+  return false;
+};
+
+class FileAccessWindow extends AbstractWindow {
+  constructor () {
+    super();
+
+    /** @type {string[]} */
+    this.paths = [];
+
+    /** @type {boolean} */
+    this.ready = false;
+
+    const ipc = this.window.webContents.ipc;
+
+    ipc.on('init', (e) => {
+      this.ready = true;
+
+      e.returnValue = {
+        locale: getLocale(),
+        strings: getStrings(),
+        APP_NAME,
+        initialPaths: this.paths,
+      };
+    });
+
+    this.window.setTitle(`${translate('file-access.window-title')} - ${APP_NAME}`);
+    this.window.setMinimizable(false);
+    this.window.setMaximizable(false);
+    this.loadURL('tw-file-access://./file-access.html');
+  }
+
+  getDimensions () {
+    return {
+      width: 600,
+      height: 300
+    };
+  }
+
+  getPreload () {
+    return 'file-access';
+  }
+
+  isPopup () {
+    return true;
+  }
+
+  /**
+   * @param {string} path
+   */
+  addPath (path) {
+    if (!this.paths.includes(path)) {
+      this.paths.push(path);
+      if (this.ready) {
+        this.window.webContents.postMessage('new-path', path);
+      }
+    }
+  }
+
+  /**
+   * @param {string} path
+   */
+  static async check (path) {
+    // This window only does anything in the Flatpak build for Linux
+    // https://github.com/electron/electron/issues/30650
+    if (getPlatform() === 'linux-flatpak' && await missingFileAccess(path)) {
+      const window = AbstractWindow.singleton(FileAccessWindow);
+      window.addPath(path);
+      window.show();
+    }
+  }
+}
+
+module.exports = FileAccessWindow;

src-main/windows/packager.js

@@ -2,6 +2,7 @@ const AbstractWindow = require('./abstract');
 const {PACKAGER_NAME} = require('../brand');
 const PackagerPreviewWindow = require('./packager-preview');
 const prompts = require('../prompts');
+const FileAccessWindow = require('./file-access-window');
 
 class PackagerWindow extends AbstractWindow {
   constructor (editorWindow) {
@@ -40,6 +41,10 @@ class PackagerWindow extends AbstractWindow {
       event.returnValue = prompts.confirm(this.window, message);
     });
 
+    ipc.handle('check-drag-and-drop-path', (event, path) => {
+      FileAccessWindow.check(path);
+    });
+
     this.window.webContents.on('did-finish-load', () => {
       // We can't do this from the preload script
       this.window.webContents.executeJavaScript(`

src-preload/editor.js

@@ -70,3 +70,20 @@ contextBridge.exposeInMainWorld('PromptsPreload', {
   alert: (message) => ipcRenderer.sendSync('alert', message),
   confirm: (message) => ipcRenderer.sendSync('confirm', message),
 });
+
+// In some Linux environments, people may try to drag & drop files that we don't have access to.
+// Remove when https://github.com/electron/electron/issues/30650 is fixed.
+if (navigator.userAgent.includes('Linux')) {
+  document.addEventListener('drop', (e) => {
+    if (e.isTrusted) {
+      for (const file of e.dataTransfer.files) {
+        // Using webUtils is safe as we don't have a legacy build for Linux
+        const {webUtils} = require('electron');
+        const path = webUtils.getPathForFile(file);
+        ipcRenderer.invoke('check-drag-and-drop-path', path);
+      }
+    }
+  }, {
+    capture: true
+  });
+}

src-preload/file-access.js

@@ -0,0 +1,14 @@
+const {ipcRenderer, contextBridge} = require('electron');
+
+let newPathCallback = () => {};
+
+contextBridge.exposeInMainWorld('FileAccessPreload', {
+  init: () => ipcRenderer.sendSync('init'),
+  onNewPath: (callback) => {
+    newPathCallback = callback;
+  }
+});
+
+ipcRenderer.on('new-path', (event, path) => {
+  newPathCallback(path);
+});

src-preload/packager.js

@@ -32,3 +32,20 @@ if (ipcRenderer.sendSync('is-mas')) {
     document.head.appendChild(style);
   });
 }
+
+// In some Linux environments, people may try to drag & drop files that we don't have access to.
+// Remove when https://github.com/electron/electron/issues/30650 is fixed.
+if (navigator.userAgent.includes('Linux')) {
+  document.addEventListener('drop', (e) => {
+    if (e.isTrusted) {
+      for (const file of e.dataTransfer.files) {
+        // Using webUtils is safe as we don't have a legacy build for Linux
+        const {webUtils} = require('electron');
+        const path = webUtils.getPathForFile(file);
+        ipcRenderer.invoke('check-drag-and-drop-path', path);
+      }
+    }
+  }, {
+    capture: true
+  });
+}

src-renderer/file-access/file-access.html

@@ -0,0 +1,140 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta charset="utf-8">
+    <meta http-equiv="Content-Security-Policy" content="default-src 'none'; style-src 'unsafe-inline'; script-src 'unsafe-inline'">
+    <style>
+      body {
+        margin: 0;
+        padding: 0;
+        font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
+        color: black;
+        background-color: white;
+        accent-color: #ff4c4c;
+      }
+      main {
+        padding: 1rem;
+        box-sizing: border-box;
+        width: 100%;
+        min-height: 100vh;
+        border: 20px solid #ff4c4c;
+        display: flex;
+        flex-direction: column;
+        gap: 0.5rem;
+      }
+      h1, p, ul {
+        margin: 0;
+      }
+      .file-path, .command {
+        font-family: monospace;
+        white-space: pre-wrap;
+        word-break: break-all;
+      }
+      .command::before {
+        content: '$ ';
+      }
+    </style>
+  </head>
+  <body>
+    <main>
+      <script>
+        // This file only does anything on Linux, so we don't need to worry about Windows paths.
+
+        const FLATPAK_APP_ID = 'org.turbowarp.TurboWarp';
+
+        // https://www.gnu.org/software/bash/manual/html_node/Double-Quotes.html
+        const escapeForShellDoubleQuotes = (string) => string
+          .replace(/\\/g, '\\\\')
+          .replace(/\$/g, '\\$')
+          .replace(/`/g, '\\`')
+          .replace(/!/g, '\\!');
+
+        const makeNode = () => ({
+          leaf: false,
+          children: Object.create(null)
+        });
+        const root = makeNode();
+
+        const addPathToGraph = (path) => {
+          const parts = path.split('/');
+          let node = root;
+
+          // Paths always start with / and the last part is the filename, so ignore first and last item.
+          for (let i = 1; i < parts.length - 1; i++) {
+            const name = parts[i];
+            if (!Object.prototype.hasOwnProperty.call(node.children, name)) {
+              node.children[name] = makeNode();
+            }
+            node = node.children[name];
+          }
+
+          node.leaf = true;
+        };
+        
+        const getLeafDirectories = () => {
+          const recurse = (path, node) => {
+            if (node.leaf) {
+              // Ignore children.
+              return [path];
+            }
+
+            const result = [];
+            for (const childName of Object.keys(node.children)) {
+              const childPath = `${path}${childName}/`;
+              const childLeaves = recurse(childPath, node.children[childName]);
+              for (const leaf of childLeaves) {
+                result.push(leaf);
+              }
+            }
+            return result;
+          };
+
+          return recurse('/', root);
+        };
+
+        const addPath = (path) => {
+          const pathElement = document.createElement('li');
+          pathElement.className = 'file-path';
+          pathElement.textContent = path;
+          fileListElement.appendChild(pathElement);
+
+          addPathToGraph(path);
+          const overrides = getLeafDirectories().map(i => {
+            // --filesystem=/ isn't valid, need to use --filesystem=host
+            const value = i === '/' ? 'host' : i;
+            return `--filesystem="${escapeForShellDoubleQuotes(value)}"`;
+          });
+          const command = `flatpak override ${FLATPAK_APP_ID} --user ${overrides.join(' ')}`;
+          commandElement.textContent = command;
+        };
+
+        FileAccessPreload.onNewPath(addPath);
+
+        const {locale, strings, APP_NAME, initialPaths} = FileAccessPreload.init();
+        document.documentElement.lang = locale;
+      </script>
+
+      <p class="introduction"></p>
+      <script>
+        document.querySelector('.introduction').textContent = strings['file-access.flatpak'].replace('{APP_NAME}', APP_NAME);
+      </script>
+
+      <ul class="file-list"></ul>
+
+      <p class="how-to-fix"></p>
+      <script>
+        document.querySelector('.how-to-fix').textContent = strings['file-access.how-to-fix'];
+      </script>
+
+      <p class="command"></p>
+
+      <script>
+        const fileListElement = document.querySelector('.file-list');
+        const commandElement = document.querySelector('.command');
+        for (const path of initialPaths) {
+          addPath(path);
+        }
+      </script>
+    </main>
+  </body>
+</html>