feat(link): add _onAttach deferred attach handler

lib/link.js

@@ -22,6 +22,8 @@ function Link(session, handle, linkPolicy) {
   this.attached = false;
   this.remoteHandle = undefined;
 
+  this._onAttach = [];
+
   var self = this;
   var stateMachine = {
     'DETACHED': {
@@ -69,14 +71,14 @@ Link.MessageReceived = 'message';
 Link.ErrorReceived = 'error';
 
 // On link credit changed.
-Link.CreditChange = 'link:creditChange';
+Link.CreditChange = 'creditChange';
 
 
 // On completion of detach.
-Link.Attached = 'link:attached';
+Link.Attached = 'attached';
 
 // On completion of detach.
-Link.Detached = 'link:detached';
+Link.Detached = 'detached';
 
 // public api
 Link.prototype.attach = function() {
@@ -113,6 +115,13 @@ Link.prototype.detach = function() {
 };
 
 // private api
+Link.prototype._resolveAttachPromises = function(err, link) {
+  while (this._onAttach.length) {
+    var attachPromise = this._onAttach.shift();
+    attachPromise(err, link);
+  }
+};
+
 Link.prototype._attachReceived = function(attachFrame) {
   this.linkSM.attachReceived();
   // process params.
@@ -121,12 +130,10 @@ Link.prototype._attachReceived = function(attachFrame) {
   debug('Rx attach CH=[' + this.session.channel + '=>' + attachFrame.channel + '], Handle=[' + this.handle + '=>' + attachFrame.handle + ']');
   this.attached = true;
 
-  // @todo: Session should listen for Link.Attached
-  this.session._linkAttached(this);
+  this.emit(Link.Attached, this);
+  this._resolveAttachPromises(null, this);
 
   this._checkCredit();
-
-  this.emit(Link.Attached, this);
 };
 
 // default implementation does nothing
@@ -151,17 +158,16 @@ Link.prototype._detached = function(frame) {
   }
 
   if (this.remoteHandle !== undefined) {
-    this.session._linksByRemoteHandle[this.remoteHandle] = undefined;
+    delete this.session._linksByRemoteHandle[this.remoteHandle];
     this.remoteHandle = undefined;
   }
 
-  this.session._linksByName[this.policy.options.name] = undefined;
-  this.session._allocatedHandles[this.policy.options.handle] = undefined;
+  delete this.session._linksByName[this.policy.options.name];
+  delete this.session._allocatedHandles[this.policy.options.handle];
   this.attached = false;
-  this.emit(Link.Detached, { closed: frame.closed, error: frame.error });
 
-  // @todo: Session should listen for Link.Detached
-  this.session._linkDetached(this);
+  this.emit(Link.Detached, { closed: frame.closed, error: frame.error });
+  this._resolveAttachPromises(frame.error ? frame.error : 'link closed');
 };
 
 module.exports = Link;