Move threads list to the Runtime

src/engine/runtime.js

@@ -10,11 +10,27 @@ function Runtime () {
     EventEmitter.call(this);
 
     // State for the runtime
-    /** @type {Object.<string, Object>} */
+    /**
+     * All blocks in the workspace.
+     * Keys are block IDs, values are metadata about the block.
+     * @type {Object.<string, Object>}
+     */
     this.blocks = {};
-    /** @type {Array.<String>} */
+
+    /**
+     * All stacks in the workspace.
+     * A list of block IDs that represent stacks (first block in stack).
+     * @type {Array.<String>}
+     */
     this.stacks = [];
 
+    /**
+     * A list of threads that are currently running in the VM.
+     * Threads are added when execution starts and pruned when execution ends.
+     * @type {Array.<Thread>}
+     */
+    this.threads = [];
+
     /** @type {!Sequencer} */
     this.sequencer = new Sequencer();
 }

src/engine/sequencer.js

@@ -1,13 +1,6 @@
 var Timer = require('../util/Timer');
 
 function Sequencer () {
-    /**
-     * A list of threads that are currently running in the VM.
-     * Threads are added when execution starts and pruned when execution ends.
-     * @type {Array.<Thread>}
-     */
-    this.threads = [];
-
     /**
      * A utility timer for timing thread sequencing.
      * @type {!Timer}
@@ -25,34 +18,36 @@ Sequencer.WORK_TIME = 1000 / 60;
 
 /**
  * Step through all threads in `this.threads`, running them in order.
+ * @return {Array.<Thread>} New threads after this round of execution.
  */
-Sequencer.prototype.stepThreads = function () {
+Sequencer.prototype.stepThreads = function (threads) {
     // Start counting toward WORK_TIME
     this.timer.start();
     // While there are still threads to run and we are within WORK_TIME,
     // continue executing threads.
-    while (this.threads.length > 0 &&
+    while (threads.length > 0 &&
            this.timer.timeElapsed() < Sequencer.WORK_TIME) {
         // New threads at the end of the iteration.
         var newThreads = [];
         // Attempt to run each thread one time
-        for (var i = 0; i < this.threads.length; i++) {
-            var activeThread = this.threads[i];
+        for (var i = 0; i < threads.length; i++) {
+            var activeThread = threads[i];
             this.stepThread(activeThread);
             if (activeThread.nextBlock !== null) {
                 newThreads.push(activeThread);
             }
         }
         // Effectively filters out threads that have stopped.
-        this.threads = newThreads;
+        threads = newThreads;
     }
+    return threads;
 };
 
 /**
  * Step the requested thread
  * @param {!Thread} thread Thread object to step
  */
-Sequencer.protoype.stepThread = function (thread) {
+Sequencer.prototype.stepThread = function (thread) {
     // @todo
 };