1 files changed, 137 insertions, 0 deletions
diff --git a/toolkit/modules/Timer.sys.mjs b/toolkit/modules/Timer.sys.mjs
new file mode 100644
index 0000000000..1d76079196
--- /dev/null
+++ b/toolkit/modules/Timer.sys.mjs
@@ -0,0 +1,137 @@
+/* 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/. */
+
+/**
+ * JS module implementation of setTimeout and clearTimeout.
+ */
+
+// This gives us >=2^30 unique timer IDs, enough for 1 per ms for 12.4 days.
+var gNextId = 1; // setTimeout and setInterval must return a positive integer
+
+var gTimerTable = new Map(); // int -> nsITimer or idleCallback
+
+// Don't generate this for every timer.
+var setTimeout_timerCallbackQI = ChromeUtils.generateQI([
+  "nsITimerCallback",
+  "nsINamed",
+]);
+
+function _setTimeoutOrIsInterval(
+  aCallback,
+  aMilliseconds,
+  aIsInterval,
+  aTarget,
+  aArgs
+) {
+  if (typeof aCallback !== "function") {
+    throw new Error(
+      `callback is not a function in ${
+        aIsInterval ? "setInterval" : "setTimeout"
+      }`
+    );
+  }
+  let id = gNextId++;
+  let timer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
+
+  if (aTarget) {
+    timer.target = aTarget;
+  }
+
+  let callback = {
+    QueryInterface: setTimeout_timerCallbackQI,
+
+    // nsITimerCallback
+    notify() {
+      if (!aIsInterval) {
+        gTimerTable.delete(id);
+      }
+      aCallback.apply(null, aArgs);
+    },
+
+    // nsINamed
+    name: `${
+      aIsInterval ? "setInterval" : "setTimeout"
+    }() for ${Cu.getDebugName(aCallback)}`,
+  };
+
+  timer.initWithCallback(
+    callback,
+    aMilliseconds,
+    aIsInterval ? timer.TYPE_REPEATING_SLACK : timer.TYPE_ONE_SHOT
+  );
+
+  gTimerTable.set(id, timer);
+  return id;
+}
+
+export function setTimeout(aCallback, aMilliseconds, ...aArgs) {
+  return _setTimeoutOrIsInterval(aCallback, aMilliseconds, false, null, aArgs);
+}
+
+export function setTimeoutWithTarget(
+  aCallback,
+  aMilliseconds,
+  aTarget,
+  ...aArgs
+) {
+  return _setTimeoutOrIsInterval(
+    aCallback,
+    aMilliseconds,
+    false,
+    aTarget,
+    aArgs
+  );
+}
+
+export function setInterval(aCallback, aMilliseconds, ...aArgs) {
+  return _setTimeoutOrIsInterval(aCallback, aMilliseconds, true, null, aArgs);
+}
+
+export function setIntervalWithTarget(
+  aCallback,
+  aMilliseconds,
+  aTarget,
+  ...aArgs
+) {
+  return _setTimeoutOrIsInterval(
+    aCallback,
+    aMilliseconds,
+    true,
+    aTarget,
+    aArgs
+  );
+}
+
+function clear(aId) {
+  if (gTimerTable.has(aId)) {
+    gTimerTable.get(aId).cancel();
+    gTimerTable.delete(aId);
+  }
+}
+export var clearInterval = clear;
+export var clearTimeout = clear;
+
+export function requestIdleCallback(aCallback, aOptions) {
+  if (typeof aCallback !== "function") {
+    throw new Error("callback is not a function in requestIdleCallback");
+  }
+  let id = gNextId++;
+
+  let callback = (...aArgs) => {
+    if (gTimerTable.has(id)) {
+      gTimerTable.delete(id);
+      aCallback(...aArgs);
+    }
+  };
+
+  ChromeUtils.idleDispatch(callback, aOptions);
+  gTimerTable.set(id, callback);
+  return id;
+}
+
+export function cancelIdleCallback(aId) {
+  if (gTimerTable.has(aId)) {
+    gTimerTable.delete(aId);
+  }
+}