scripting: Switch to standard async/await pattern

The original scripting framework was based on SpiderMonkey's
pre-standard generators, and was simply translated to the
corresponding standard syntax when updating it to work with
recent JS versions.

We can do even better by using the standard async/await pattern
instead of generators/yield.

https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1396

js/perf/core.js

@@ -70,7 +70,8 @@ let WINDOW_CONFIGS = [
     { width: 640, height: 480, alpha: true,  maximized: false, count: 10, metric: 'overviewFps10Alpha' },
 ];
 
-function *run() {
+async function run() {
+    /* eslint-disable no-await-in-loop */
     Scripting.defineScriptEvent("overviewShowStart", "Starting to show the overview");
     Scripting.defineScriptEvent("overviewShowDone", "Overview finished showing");
     Scripting.defineScriptEvent("afterShowHide", "After a show/hide cycle for the overview");
@@ -84,7 +85,7 @@ function *run() {
         Scripting.scriptEvent('overviewShowDone');
     });
 
-    yield Scripting.sleep(1000);
+    await Scripting.sleep(1000);
 
     for (let i = 0; i < 2 * WINDOW_CONFIGS.length; i++) {
         // We go to the overview twice for each configuration; the first time
@@ -92,49 +93,50 @@ function *run() {
         // a clean set of numbers.
         if ((i % 2) == 0) {
             let config = WINDOW_CONFIGS[i / 2];
-            yield Scripting.destroyTestWindows();
+            await Scripting.destroyTestWindows();
 
             for (let k = 0; k < config.count; k++) {
-                yield Scripting.createTestWindow({ width: config.width,
+                await Scripting.createTestWindow({ width: config.width,
                                                    height: config.height,
                                                    alpha: config.alpha,
                                                    maximized: config.maximized });
             }
 
-            yield Scripting.waitTestWindows();
+            await Scripting.waitTestWindows();
-            yield Scripting.sleep(1000);
+            await Scripting.sleep(1000);
-            yield Scripting.waitLeisure();
+            await Scripting.waitLeisure();
         }
 
         Scripting.scriptEvent('overviewShowStart');
         Main.overview.show();
 
-        yield Scripting.waitLeisure();
+        await Scripting.waitLeisure();
         Main.overview.hide();
-        yield Scripting.waitLeisure();
+        await Scripting.waitLeisure();
 
         System.gc();
-        yield Scripting.sleep(1000);
+        await Scripting.sleep(1000);
         Scripting.collectStatistics();
         Scripting.scriptEvent('afterShowHide');
     }
 
-    yield Scripting.destroyTestWindows();
+    await Scripting.destroyTestWindows();
-    yield Scripting.sleep(1000);
+    await Scripting.sleep(1000);
 
     Main.overview.show();
-    yield Scripting.waitLeisure();
+    await Scripting.waitLeisure();
 
     for (let i = 0; i < 2; i++) {
         Scripting.scriptEvent('applicationsShowStart');
         // eslint-disable-next-line require-atomic-updates
         Main.overview.dash.showAppsButton.checked = true;
-        yield Scripting.waitLeisure();
+        await Scripting.waitLeisure();
         Scripting.scriptEvent('applicationsShowDone');
         // eslint-disable-next-line require-atomic-updates
         Main.overview.dash.showAppsButton.checked = false;
-        yield Scripting.waitLeisure();
+        await Scripting.waitLeisure();
     }
+    /* eslint-enable no-await-in-loop */
 }
 
 let showingOverview = false;

js/perf/hwtest.js

@@ -94,7 +94,8 @@ function extractBootTimestamp() {
     return result;
 }
 
-function *run() {
+async function run() {
+    /* eslint-disable no-await-in-loop */
     Scripting.defineScriptEvent("desktopShown", "Finished initial animation");
     Scripting.defineScriptEvent("overviewShowStart", "Starting to show the overview");
     Scripting.defineScriptEvent("overviewShowDone", "Overview finished showing");
@@ -110,7 +111,7 @@ function *run() {
     Scripting.defineScriptEvent("geditLaunch", "gedit application launch");
     Scripting.defineScriptEvent("geditFirstFrame", "first frame of gedit window drawn");
 
-    yield Scripting.waitLeisure();
+    await Scripting.waitLeisure();
     Scripting.scriptEvent('desktopShown');
 
     let interfaceSettings = new Gio.Settings({
@@ -120,22 +121,22 @@ function *run() {
 
     Scripting.scriptEvent('overviewShowStart');
     Main.overview.show();
-    yield Scripting.waitLeisure();
+    await Scripting.waitLeisure();
     Scripting.scriptEvent('overviewShowDone');
 
-    yield Scripting.sleep(1000);
+    await Scripting.sleep(1000);
 
     Scripting.scriptEvent('applicationsShowStart');
     // eslint-disable-next-line require-atomic-updates
     Main.overview.dash.showAppsButton.checked = true;
 
-    yield Scripting.waitLeisure();
+    await Scripting.waitLeisure();
     Scripting.scriptEvent('applicationsShowDone');
 
-    yield Scripting.sleep(1000);
+    await Scripting.sleep(1000);
 
     Main.overview.hide();
-    yield Scripting.waitLeisure();
+    await Scripting.waitLeisure();
 
     // --------------------- //
     // Tests of redraw speed //
@@ -145,46 +146,46 @@ function *run() {
     global.frame_finish_timestamp = true;
 
     for (let k = 0; k < 5; k++)
-        yield Scripting.createTestWindow({ maximized: true });
+        await Scripting.createTestWindow({ maximized: true });
-    yield Scripting.waitTestWindows();
+    await Scripting.waitTestWindows();
 
-    yield Scripting.sleep(1000);
+    await Scripting.sleep(1000);
 
     Scripting.scriptEvent('mainViewDrawStart');
-    yield waitAndDraw(1000);
+    await waitAndDraw(1000);
     Scripting.scriptEvent('mainViewDrawDone');
 
     Main.overview.show();
     Scripting.waitLeisure();
 
-    yield Scripting.sleep(1500);
+    await Scripting.sleep(1500);
 
     Scripting.scriptEvent('overviewDrawStart');
-    yield waitAndDraw(1000);
+    await waitAndDraw(1000);
     Scripting.scriptEvent('overviewDrawDone');
 
-    yield Scripting.destroyTestWindows();
+    await Scripting.destroyTestWindows();
     Main.overview.hide();
 
-    yield Scripting.createTestWindow({ maximized: true,
+    await Scripting.createTestWindow({ maximized: true,
                                        redraws: true });
-    yield Scripting.waitTestWindows();
+    await Scripting.waitTestWindows();
 
-    yield Scripting.sleep(1000);
+    await Scripting.sleep(1000);
 
     Scripting.scriptEvent('redrawTestStart');
-    yield Scripting.sleep(1000);
+    await Scripting.sleep(1000);
     Scripting.scriptEvent('redrawTestDone');
 
-    yield Scripting.sleep(1000);
+    await Scripting.sleep(1000);
     Scripting.scriptEvent('collectTimings');
 
-    yield Scripting.destroyTestWindows();
+    await Scripting.destroyTestWindows();
 
     global.frame_timestamps = false;
     global.frame_finish_timestamp = false;
 
-    yield Scripting.sleep(1000);
+    await Scripting.sleep(1000);
 
     let appSys = Shell.AppSystem.get_default();
     let app = appSys.lookup_app('org.gnome.gedit.desktop');
@@ -197,21 +198,22 @@ function *run() {
         throw new Error('gedit was already running');
 
     while (windows.length == 0) {
-        yield waitSignal(global.display, 'window-created');
+        await waitSignal(global.display, 'window-created');
         windows = app.get_windows();
     }
 
     let actor = windows[0].get_compositor_private();
-    yield waitSignal(actor, 'first-frame');
+    await waitSignal(actor, 'first-frame');
     Scripting.scriptEvent('geditFirstFrame');
 
-    yield Scripting.sleep(1000);
+    await Scripting.sleep(1000);
 
     windows[0].delete(global.get_current_time());
 
-    yield Scripting.sleep(1000);
+    await Scripting.sleep(1000);
 
     interfaceSettings.set_boolean('enable-animations', true);
+    /* eslint-enable no-await-in-loop */
 }
 
 let overviewShowStart;

js/ui/scripting.js

@@ -21,16 +21,13 @@ const { loadInterfaceXML } = imports.misc.fileUtils;
 // When scripting an automated test we want to make a series of calls
 // in a linear fashion, but we also want to be able to let the main
 // loop run so actions can finish. For this reason we write the script
-// as a generator function that yields when it want to let the main
+// as an async function that uses await when it wants to let the main
 // loop run.
 //
-//    yield Scripting.sleep(1000);
+//    await Scripting.sleep(1000);
 //    main.overview.show();
-//    yield Scripting.waitLeisure();
+//    await Scripting.waitLeisure();
 //
-// While it isn't important to the person writing the script, the actual
-// yielded result is a function that the caller uses to provide the
-// callback for resuming the script.
 
 /**
  * sleep:
@@ -285,13 +282,11 @@ function _collect(scriptModule, outputFile) {
 }
 
 async function _runPerfScript(scriptModule, outputFile) {
-    for (let step of scriptModule.run()) {
+    try {
-        try {
+        await scriptModule.run();
-            await step; // eslint-disable-line no-await-in-loop
+    } catch (err) {
-        } catch (err) {
+        log(`Script failed: ${err}\n${err.stack}`);
-            log(`Script failed: ${err}\n${err.stack}`);
+        Meta.exit(Meta.ExitCode.ERROR);
-            Meta.exit(Meta.ExitCode.ERROR);
-        }
     }
 
     try {