timers: implement setImmediate

1 files changed, 71 insertions, 0 deletions

diff --git a/lib/timers.js b/lib/timers.js
index 03db989b11..2d50cbddec 100644
--- a/lib/timers.js
+++ b/lib/timers.js
@@ -277,3 +277,74 @@ Timeout.prototype.close = function() {
     exports.unenroll(this);
   }
 };
+
+
+var immediateTimer = null;
+var immediateQueue = { started: false };
+L.init(immediateQueue);
+
+
+function lazyImmediateInit() { // what's in a name?
+  if (immediateTimer) return;
+  immediateTimer = new Timer;
+  immediateTimer.ontimeout = processImmediate;
+}
+
+
+function processImmediate() {
+  var immediate;
+  if (L.isEmpty(immediateQueue)) {
+    immediateTimer.stop();
+    immediateQueue.started = false;
+  } else {
+    immediate = L.shift(immediateQueue);
+
+    if (immediate.domain) immediate.domain.enter();
+
+    immediate._onTimeout();
+
+    if (immediate.domain) immediate.domain.exit();
+  }
+};
+
+
+exports.setImmediate = function(callback) {
+  var immediate = {}, args;
+
+  L.init(immediate);
+
+  immediate._onTimeout = callback;
+
+  if (arguments.length > 1) {
+    args = Array.prototype.slice.call(arguments, 1);
+    immediate._onTimeout = function() {
+      callback.apply(null, args);
+    };
+  }
+
+  if (!immediateQueue.started) {
+    lazyImmediateInit();
+    immediateTimer.start(0, 1);
+    immediateQueue.started = true;
+  }
+
+  if (process.domain) immediate.domain = process.domain;
+
+  L.append(immediateQueue, immediate);
+
+  return immediate;
+};
+
+
+exports.clearImmediate = function(immediate) {
+  if (!immediate) return;
+
+  immediate._onTimeout = undefined;
+
+  L.remove(immediate);
+
+  if (L.isEmpty(immediateQueue)) {
+    immediateTimer.stop();
+    immediateQueue.started = false;
+  }
+};