Bug 1743878 - Avoid opening caret browsing dialogs when already open. r=dholbert

Differential Revision: https://phabricator.services.mozilla.com/D160166

browser/base/content/tabbrowser.js

@@ -104,6 +104,8 @@
 
     _isBusy: false,
 
+    _awaitingToggleCaretBrowsingPrompt: false,
+
     arrowKeysShouldWrap: AppConstants == "macosx",
 
     _dateTimePicker: null,
@@ -5428,7 +5430,7 @@
       const kPrefCaretBrowsingOn = "accessibility.browsewithcaret";
 
       var isEnabled = Services.prefs.getBoolPref(kPrefShortcutEnabled);
-      if (!isEnabled) {
+      if (!isEnabled || this._awaitingToggleCaretBrowsingPrompt) {
         return;
       }
 
@@ -5442,20 +5444,28 @@
         var checkValue = { value: false };
         var promptService = Services.prompt;
 
-        var buttonPressed = promptService.confirmEx(
-          window,
-          gTabBrowserBundle.GetStringFromName(
-            "browsewithcaret.checkWindowTitle"
-          ),
-          gTabBrowserBundle.GetStringFromName("browsewithcaret.checkLabel"),
-          // Make "No" the default:
-          promptService.STD_YES_NO_BUTTONS | promptService.BUTTON_POS_1_DEFAULT,
-          null,
-          null,
-          null,
-          gTabBrowserBundle.GetStringFromName("browsewithcaret.checkMsg"),
-          checkValue
-        );
+        try {
+          this._awaitingToggleCaretBrowsingPrompt = true;
+          var buttonPressed = promptService.confirmEx(
+            window,
+            gTabBrowserBundle.GetStringFromName(
+              "browsewithcaret.checkWindowTitle"
+            ),
+            gTabBrowserBundle.GetStringFromName("browsewithcaret.checkLabel"),
+            // Make "No" the default:
+            promptService.STD_YES_NO_BUTTONS |
+              promptService.BUTTON_POS_1_DEFAULT,
+            null,
+            null,
+            null,
+            gTabBrowserBundle.GetStringFromName("browsewithcaret.checkMsg"),
+            checkValue
+          );
+        } catch (ex) {
+          return;
+        } finally {
+          this._awaitingToggleCaretBrowsingPrompt = false;
+        }
         if (buttonPressed != 0) {
           if (checkValue.value) {
             try {

toolkit/content/tests/browser/browser_f7_caret_browsing.js

@@ -298,3 +298,70 @@ add_task(async function toggleCheckboxWantCaretBrowsing() {
 
   BrowserTestUtils.removeTab(tab);
 });
+
+// Test for bug 1743878: Many repeated modal caret-browsing dialogs, if you
+// accidentally hold down F7 for a few seconds
+add_task(async function testF7SpamDoesNotOpenDialogs() {
+  let tab = await BrowserTestUtils.openNewForegroundTab(gBrowser);
+  registerCleanupFunction(() => BrowserTestUtils.removeTab(tab));
+
+  let promiseGotKey = promiseCaretPromptOpened();
+  hitF7();
+  let prompt = await promiseGotKey;
+  let doc = prompt.document;
+  let dialog = doc.getElementById("commonDialog");
+
+  let promiseDialogUnloaded = BrowserTestUtils.waitForEvent(prompt, "unload");
+
+  // Listen for an additional prompt to open, which should not happen.
+  let promiseDialogOrTimeout = () =>
+    Promise.race([
+      promiseCaretPromptOpened(),
+      // eslint-disable-next-line mozilla/no-arbitrary-setTimeout
+      new Promise(resolve => setTimeout(resolve, 100)),
+    ]);
+
+  let openedPromise = promiseDialogOrTimeout();
+
+  // Hit F7 two more times: once to test that _awaitingToggleCaretBrowsingPrompt
+  // is applied, and again to test that its value isn't somehow reset by
+  // pressing F7 while the dialog is open.
+  for (let i = 0; i < 2; i++) {
+    await new Promise(resolve =>
+      SimpleTest.executeSoon(() => {
+        hitF7();
+        resolve();
+      })
+    );
+  }
+
+  // Say no:
+  dialog.cancelDialog();
+  await promiseDialogUnloaded;
+  info("Dialog unloaded");
+
+  let openedDialog = await openedPromise;
+  ok(!openedDialog, "No additional dialog should have opened.");
+
+  // If the test fails, clean up any dialogs we erroneously opened so they don't
+  // interfere with other tests.
+  let extraDialogs = 0;
+  while (openedDialog) {
+    extraDialogs += 1;
+    let doc = openedDialog.document;
+    let dialog = doc.getElementById("commonDialog");
+    openedPromise = promiseDialogOrTimeout();
+    dialog.cancelDialog();
+    openedDialog = await openedPromise;
+  }
+  if (extraDialogs) {
+    info(`Closed ${extraDialogs} extra dialogs.`);
+  }
+
+  // Either way, we now have an extra observer, so clean it up.
+  gCaretPromptOpeningObserver();
+
+  Services.prefs.setBoolPref(kPrefShortcutEnabled, true);
+  Services.prefs.setBoolPref(kPrefWarnOnEnable, true);
+  Services.prefs.setBoolPref(kPrefCaretBrowsingOn, false);
+});