08-27-周三_17-09-29

node_modules/weak/lib/weak.js

@@ -0,0 +1,110 @@
+
+/**
+ * Module dependencies.
+ */
+
+var Emitter = require('events').EventEmitter;
+var bindings = require('bindings')('weakref.node');
+
+/**
+ * Set global weak callback function.
+ */
+
+bindings._setCallback(callback);
+
+/**
+ * Module exports.
+ */
+
+exports = module.exports = create;
+exports.addCallback = exports.addListener = addCallback;
+exports.removeCallback = exports.removeListener = removeCallback;
+exports.removeCallbacks = exports.removeListeners = removeCallbacks;
+exports.callbacks = exports.listeners = callbacks;
+
+// backwards-compat with node-weakref
+exports.weaken = exports.create = exports;
+
+// re-export all the binding functions onto the exports
+Object.keys(bindings).forEach(function (name) {
+  exports[name] = bindings[name];
+});
+
+/**
+ * Internal emitter event name.
+ * This is completely arbitrary...
+ * Could be any value....
+ */
+
+var CB = '_CB';
+
+/**
+ * Creates and returns a new Weakref instance. Optionally attaches
+ * a weak callback to invoke when the Object gets garbage collected.
+ *
+ * @api public
+ */
+
+function create (obj, fn) {
+  var weakref = bindings._create(obj, new Emitter());
+  if ('function' == typeof fn) {
+    exports.addCallback(weakref, fn);
+  }
+  return weakref;
+}
+
+/**
+ * Adds a weak callback function to the Weakref instance.
+ *
+ * @api public
+ */
+
+function addCallback (weakref, fn) {
+  var emitter = bindings._getEmitter(weakref);
+  return emitter.on(CB, fn);
+}
+
+/**
+ * Removes a weak callback function from the Weakref instance.
+ *
+ * @api public
+ */
+
+function removeCallback (weakref, fn) {
+  var emitter = bindings._getEmitter(weakref);
+  return emitter.removeListener(CB, fn);
+}
+
+/**
+ * Returns a copy of the listeners on the Weakref instance.
+ *
+ * @api public
+ */
+
+function callbacks (weakref) {
+  var emitter = bindings._getEmitter(weakref);
+  return emitter.listeners(CB);
+}
+
+
+/**
+ * Removes all callbacks on the Weakref instance.
+ *
+ * @api public
+ */
+
+function removeCallbacks (weakref) {
+  var emitter = bindings._getEmitter(weakref);
+  return emitter.removeAllListeners(CB);
+}
+
+/**
+ * Common weak callback function.
+ *
+ * @api private
+ */
+
+function callback (emitter) {
+  emitter.emit(CB);
+  emitter = null;
+}