From 9c785ca6b660c38252548b6c7d51cfb9c68e0bbf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Florian=20M=C3=BCllner?= <fmuellner@gnome.org>
Date: Wed, 22 Jan 2020 15:07:45 +0100
Subject: [PATCH] extensionDownloader: Make checkForUpdates() check for updates

Currently the method installs updates instead of merely checking for
them (or it would do, if it actually worked).

This is not just surprising considering the method name, the whole idea
of live updates is problematic and will not work properly more often
than not:
 - imports are cached, so any local modules will stay at their
   original version until a shell restart
 - GTypes cannot be unregistered

So change the method to only download available updates, and set the
extensions' hasUpdate state accordingly.

https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/945
---
 js/ui/extensionDownloader.js | 50 ++++++------------------------------
 1 file changed, 8 insertions(+), 42 deletions(-)

diff --git a/js/ui/extensionDownloader.js b/js/ui/extensionDownloader.js
index 768b5dcc6..2ae64ea44 100644
--- a/js/ui/extensionDownloader.js
+++ b/js/ui/extensionDownloader.js
@@ -1,6 +1,5 @@
 // -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-
-/* exported init, installExtension, uninstallExtension,
-            checkForUpdates, updateExtension */
+/* exported init, installExtension, uninstallExtension, checkForUpdates */
 
 const { Clutter, Gio, GLib, GObject, Soup } = imports.gi;
 
@@ -100,13 +99,9 @@ function gotExtensionZipFile(session, message, uuid, dir, callback, errback) {
     });
 }
 
-function updateExtension(uuid) {
-    // This gets a bit tricky. We want the update to be seamless -
-    // if we have any error during downloading or extracting, we
-    // want to not unload the current version.
-
-    let oldExtensionTmpDir = GLib.Dir.make_tmp('XXXXXX-shell-extension');
-    let newExtensionTmpDir = GLib.Dir.make_tmp('XXXXXX-shell-extension');
+function downloadExtensionUpdate(uuid) {
+    let dir = Gio.File.new_for_path(
+        GLib.build_filenamev([global.userdatadir, 'extension-updates', uuid]));
 
     let params = { shell_version: Config.PACKAGE_VERSION };
 
@@ -114,39 +109,10 @@ function updateExtension(uuid) {
     let message = Soup.form_request_new_from_hash('GET', url, params);
 
     _httpSession.queue_message(message, session => {
-        gotExtensionZipFile(session, message, uuid, newExtensionTmpDir, () => {
-            let oldExtension = Main.extensionManager.lookup(uuid);
-            let extensionDir = oldExtension.dir;
-
-            if (!Main.extensionManager.unloadExtension(oldExtension))
-                return;
-
-            FileUtils.recursivelyMoveDir(extensionDir, oldExtensionTmpDir);
-            FileUtils.recursivelyMoveDir(newExtensionTmpDir, extensionDir);
-
-            let extension = null;
-
-            try {
-                extension = Main.extensionManager.createExtensionObject(uuid, extensionDir, ExtensionUtils.ExtensionType.PER_USER);
-                Main.extensionManager.loadExtension(extension);
-            } catch (e) {
-                if (extension)
-                    Main.extensionManager.unloadExtension(extension);
-
-                logError(e, 'Error loading extension %s'.format(uuid));
-
-                FileUtils.recursivelyDeleteDir(extensionDir, false);
-                FileUtils.recursivelyMoveDir(oldExtensionTmpDir, extensionDir);
-
-                // Restore what was there before. We can't do much if we
-                // fail here.
-                Main.extensionManager.loadExtension(oldExtension);
-                return;
-            }
-
-            FileUtils.recursivelyDeleteDir(oldExtensionTmpDir, true);
+        gotExtensionZipFile(session, message, uuid, dir, () => {
+            Main.extensionManager.notifyExtensionUpdate(uuid);
         }, (code, msg) => {
-            log(`Error while updating extension ${uuid}: ${code} (${msg})`);
+            log(`Error while downloading update for extension ${uuid}: ${code} (${msg})`);
         });
     });
 }
@@ -172,7 +138,7 @@ function checkForUpdates() {
             if (operation == 'blacklist')
                 uninstallExtension(uuid);
             else if (operation == 'upgrade' || operation == 'downgrade')
-                updateExtension(uuid);
+                downloadExtensionUpdate(uuid);
         }
     });
 }