1 files changed, 125 insertions, 0 deletions
diff --git a/editor/AsyncSpellCheckTestHelper.sys.mjs b/editor/AsyncSpellCheckTestHelper.sys.mjs
new file mode 100644
index 0000000000..6ceb2a86b2
--- /dev/null
+++ b/editor/AsyncSpellCheckTestHelper.sys.mjs
@@ -0,0 +1,125 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+const SPELL_CHECK_ENDED_TOPIC = "inlineSpellChecker-spellCheck-ended";
+const SPELL_CHECK_STARTED_TOPIC = "inlineSpellChecker-spellCheck-started";
+
+const CP = Cc["@mozilla.org/content-pref/service;1"].getService(
+  Ci.nsIContentPrefService2
+);
+
+/**
+ * Waits until spell checking has stopped on the given element.
+ *
+ * When a spell check is pending, this waits indefinitely until the spell check
+ * ends.  When a spell check is not pending, it waits a small number of turns of
+ * the event loop: if a spell check begins, it resumes waiting indefinitely for
+ * the end, and otherwise it stops waiting and calls the callback.
+ *
+ * This this can therefore trap spell checks that have not started at the time
+ * of calling, spell checks that have already started, multiple consecutive
+ * spell checks, and the absence of spell checks altogether.
+ *
+ * @param editableElement  The element being spell checked.
+ * @param callback         Called when spell check has completed or enough turns
+ *                         of the event loop have passed to determine it has not
+ *                         started.
+ */
+export function maybeOnSpellCheck(editableElement, callback) {
+  let editor = editableElement.editor;
+  if (!editor) {
+    let win = editableElement.ownerGlobal;
+    editor = win.docShell.editingSession.getEditorForWindow(win);
+  }
+  if (!editor) {
+    throw new Error("Unable to find editor for element " + editableElement);
+  }
+
+  try {
+    // False is important here.  Pass false so that the inline spell checker
+    // isn't created if it doesn't already exist.
+    var isc = editor.getInlineSpellChecker(false);
+  } catch (err) {
+    // getInlineSpellChecker throws if spell checking is not enabled instead of
+    // just returning null, which seems kind of lame.  (Spell checking is not
+    // enabled on Android.)  The point here is only to determine whether spell
+    // check is pending, and if getInlineSpellChecker throws, then it's not
+    // pending.
+  }
+  let waitingForEnded = isc && isc.spellCheckPending;
+  let count = 0;
+
+  function observe(subj, topic, data) {
+    if (subj != editor) {
+      return;
+    }
+    count = 0;
+    let expectedTopic = waitingForEnded
+      ? SPELL_CHECK_ENDED_TOPIC
+      : SPELL_CHECK_STARTED_TOPIC;
+    if (topic != expectedTopic) {
+      console.error("Expected " + expectedTopic + " but got " + topic + "!");
+    }
+    waitingForEnded = !waitingForEnded;
+  }
+
+  // eslint-disable-next-line mozilla/use-services
+  let os = Cc["@mozilla.org/observer-service;1"].getService(
+    Ci.nsIObserverService
+  );
+  os.addObserver(observe, SPELL_CHECK_STARTED_TOPIC);
+  os.addObserver(observe, SPELL_CHECK_ENDED_TOPIC);
+
+  let timer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
+  timer.init(
+    function tick() {
+      // Wait an arbitrarily large number -- 100 -- turns of the event loop before
+      // declaring that no spell checks will start.
+      if (waitingForEnded || ++count < 100) {
+        return;
+      }
+      timer.cancel();
+      os.removeObserver(observe, SPELL_CHECK_STARTED_TOPIC);
+      os.removeObserver(observe, SPELL_CHECK_ENDED_TOPIC);
+      callback();
+    },
+    0,
+    Ci.nsITimer.TYPE_REPEATING_SLACK
+  );
+}
+
+/**
+ * Waits until spell checking has stopped on the given element.
+ *
+ * @param editableElement  The element being spell checked.
+ * @param callback         Called when spell check has completed or enough turns
+ *                         of the event loop have passed to determine it has not
+ *                         started.
+ */
+export function onSpellCheck(editableElement, callback) {
+  const { TestUtils } = ChromeUtils.importESModule(
+    "resource://testing-common/TestUtils.sys.mjs"
+  );
+
+  let editor = editableElement.editor;
+  TestUtils.topicObserved(SPELL_CHECK_ENDED_TOPIC, s => s == editor).then(
+    callback
+  );
+}
+
+export async function getDictionaryContentPref() {
+  let dictionaries = await new Promise(resolve => {
+    let value = "";
+    CP.getByDomainAndName("mochi.test", "spellcheck.lang", null, {
+      handleResult(pref) {
+        value = pref.value;
+      },
+      handleCompletion() {
+        resolve(value);
+      },
+    });
+  });
+
+  return dictionaries;
+}