diff Implab/Deferred.cs @ 244:eee3e49dd1ff v3

working on promises
author cin
date Thu, 25 Jan 2018 19:09:16 +0300
parents
children b904e0a3ba72
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line diff
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Implab/Deferred.cs	Thu Jan 25 19:09:16 2018 +0300
@@ -0,0 +1,52 @@
+using System;
+using System.Diagnostics;
+
+namespace Implab {
+    /// <summary>
+    /// This class is responsible for the promise resolution, dispatching and chaining
+    /// </summary>
+    public class Deferred : IResolvable {
+
+        readonly AbstractPromise m_promise;
+        readonly IDispatcher m_dispatcher;
+
+        internal Deferred(AbstractPromise promise, IDispatcher dispatcher) {
+            Debug.Assert(promise != null);
+            m_promise = promise;
+            m_dispatcher = dispatcher;
+        }
+
+        public IPromise Promise {
+            get { return m_promise; }
+        }
+
+        public void Reject(Exception error) {
+            m_promise.Reject(error);
+        }
+
+        public void Resolve() {
+            m_promise.Resolve();
+        }
+
+        public void Resolve(IPromise thenable) {
+            if (thenable == null)
+                Reject(new Exception("The promise or task are expected"));
+            if (thenable == m_promise)
+                Reject(new Exception("The promise cannot be resolved with oneself"));
+
+            else if (m_dispatcher != null)
+                // dispatch (see ecma-262/6.0: 25.4.1.3.2 Promise Resolve Functions)
+                m_dispatcher.Enqueue(() => thenable.Then(this));
+            else
+                thenable.Then(this);
+        }
+
+        void Chain(IPromise thenable) {
+            try {
+                thenable.Then(this);
+            } catch (Exception err) {
+                Reject(err);
+            }
+        }
+    }
+}
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