Gracefully shut down database operations before app exit

js/background.js

@@ -272,6 +272,10 @@
         const clearDataView = new window.Whisper.ClearDataView().render();
         $('body').append(clearDataView.el);
       },
+
+      shutdown: async () => {
+        await window.Signal.Data.shutdown();
+      },
     };
 
     const currentVersion = window.getVersion();

js/models/messages.js

@@ -844,7 +844,13 @@
       return this.OUR_NUMBER;
     },
     getContact() {
-      return ConversationController.getOrCreate(this.getSource(), 'private');
+      const source = this.getSource();
+
+      if (!source) {
+        return null;
+      }
+
+      return ConversationController.getOrCreate(source, 'private');
     },
     isOutgoing() {
       return this.get('type') === 'outgoing';

js/modules/data.js

@@ -32,6 +32,9 @@ const CLEANUP_ORPHANED_ATTACHMENTS_KEY = 'cleanup-orphaned-attachments';
 const _jobs = Object.create(null);
 const _DEBUG = false;
 let _jobCounter = 0;
+let _shuttingDown = false;
+let _shutdownCallback = null;
+let _shutdownPromise = null;
 
 const channels = {};
 
@@ -39,6 +42,7 @@ module.exports = {
   _jobs,
   _cleanData,
 
+  shutdown,
   close,
   removeDB,
   removeIndexedDBFiles,
@@ -172,7 +176,45 @@ function _cleanData(data) {
   return data;
 }
 
+async function _shutdown() {
+  if (_shutdownPromise) {
+    return _shutdownPromise;
+  }
+
+  _shuttingDown = true;
+
+  const jobKeys = Object.keys(_jobs);
+  window.log.info(
+    `data.shutdown: starting process. ${jobKeys.length} jobs outstanding`
+  );
+
+  // No outstanding jobs, return immediately
+  if (jobKeys.length === 0) {
+    return null;
+  }
+
+  // Outstanding jobs; we need to wait until the last one is done
+  _shutdownPromise = new Promise((resolve, reject) => {
+    _shutdownCallback = error => {
+      window.log.info('data.shutdown: process complete');
+      if (error) {
+        return reject(error);
+      }
+
+      return resolve();
+    };
+  });
+
+  return _shutdownPromise;
+}
+
 function _makeJob(fnName) {
+  if (_shuttingDown && fnName !== 'close') {
+    throw new Error(
+      `Rejecting SQL channel job (${fnName}); application is shutting down`
+    );
+  }
+
   _jobCounter += 1;
   const id = _jobCounter;
 
@@ -219,8 +261,16 @@ function _updateJob(id, data) {
 function _removeJob(id) {
   if (_DEBUG) {
     _jobs[id].complete = true;
-  } else {
-    delete _jobs[id];
+    return;
+  }
+
+  delete _jobs[id];
+
+  if (_shutdownCallback) {
+    const keys = Object.keys(_jobs);
+    if (keys.length === 0) {
+      _shutdownCallback();
+    }
   }
 }
 
@@ -310,6 +360,14 @@ function keysFromArrayBuffer(keys, data) {
 
 // Top-level calls
 
+async function shutdown() {
+  // Stop accepting new SQL jobs, flush outstanding queue
+  await _shutdown();
+
+  // Close database
+  await close();
+}
+
 // Note: will need to restart the app after calling this, to set up afresh
 async function close() {
   await channels.close();

main.js

@@ -329,27 +329,43 @@ function createWindow() {
   captureClicks(mainWindow);
 
   // Emitted when the window is about to be closed.
-  mainWindow.on('close', e => {
+  // Note: We do most of our shutdown logic here because all windows are closed by
+  //   Electron before the app quits.
+  mainWindow.on('close', async e => {
+    console.log('close event', {
+      readyForShutdown: mainWindow ? mainWindow.readyForShutdown : null,
+      shouldQuit: windowState.shouldQuit(),
+    });
     // If the application is terminating, just do the default
     if (
-      windowState.shouldQuit() ||
       config.environment === 'test' ||
-      config.environment === 'test-lib'
+      config.environment === 'test-lib' ||
+      (mainWindow.readyForShutdown && windowState.shouldQuit())
     ) {
       return;
     }
 
+    // Prevent the shutdown
+    e.preventDefault();
+    mainWindow.hide();
+
     // On Mac, or on other platforms when the tray icon is in use, the window
     // should be only hidden, not closed, when the user clicks the close button
-    if (usingTrayIcon || process.platform === 'darwin') {
-      e.preventDefault();
-      mainWindow.hide();
-
+    if (
+      !windowState.shouldQuit() &&
+      (usingTrayIcon || process.platform === 'darwin')
+    ) {
       // toggle the visibility of the show/hide tray icon menu entries
       if (tray) {
         tray.updateContextMenu();
       }
+
+      return;
     }
+
+    await requestShutdown();
+    mainWindow.readyForShutdown = true;
+    app.quit();
   });
 
   // Emitted when the window is closed.
@@ -691,7 +707,51 @@ function setupMenu(options) {
   Menu.setApplicationMenu(menu);
 }
 
+async function requestShutdown() {
+  if (!mainWindow || !mainWindow.webContents) {
+    return;
+  }
+
+  console.log('requestShutdown: Requesting close of mainWindow...');
+  const request = new Promise((resolve, reject) => {
+    ipc.once('now-ready-for-shutdown', (_event, error) => {
+      console.log('requestShutdown: Response received');
+
+      if (error) {
+        return reject(error);
+      }
+
+      return resolve();
+    });
+    mainWindow.webContents.send('get-ready-for-shutdown');
+
+    // We'll wait two minutes, then force the app to go down. This can happen if someone
+    //   exits the app before we've set everything up in preload() (so the browser isn't
+    //   yet listening for these events), or if there are a whole lot of stacked-up tasks.
+    // Note: two minutes is also our timeout for SQL tasks in data.js in the browser.
+    setTimeout(() => {
+      console.log(
+        'requestShutdown: Response never received; forcing shutdown.'
+      );
+      resolve();
+    }, 2 * 60 * 1000);
+  });
+
+  try {
+    await request;
+  } catch (error) {
+    console.log(
+      'requestShutdown error:',
+      error && error.stack ? error.stack : error
+    );
+  }
+}
+
 app.on('before-quit', () => {
+  console.log('before-quit event', {
+    readyForShutdown: mainWindow ? mainWindow.readyForShutdown : null,
+    shouldQuit: windowState.shouldQuit(),
+  });
   windowState.markShouldQuit();
 });
 

preload.js

@@ -151,6 +151,25 @@ ipc.on('delete-all-data', () => {
   }
 });
 
+ipc.on('get-ready-for-shutdown', async () => {
+  const { shutdown } = window.Events;
+  if (!shutdown) {
+    window.log.error('preload shutdown handler: shutdown method not found');
+    ipc.send('now-ready-for-shutdown');
+    return;
+  }
+
+  try {
+    await shutdown();
+    ipc.send('now-ready-for-shutdown');
+  } catch (error) {
+    ipc.send(
+      'now-ready-for-shutdown',
+      error && error.stack ? error.stack : error
+    );
+  }
+});
+
 function installGetter(name, functionName) {
   ipc.on(`get-${name}`, async () => {
     const getFn = window.Events[functionName];
@@ -159,7 +178,10 @@ function installGetter(name, functionName) {
       try {
         ipc.send(`get-success-${name}`, null, await getFn());
       } catch (error) {
-        ipc.send(`get-success-${name}`, error);
+        ipc.send(
+          `get-success-${name}`,
+          error && error.stack ? error.stack : error
+        );
       }
     }
   });