From 625c6ea4b3f432964dd29336fdd7faf73703de0f Mon Sep 17 00:00:00 2001
From: Daniel Huigens <d.huigens@protonmail.com>
Date: Wed, 9 Jan 2019 15:05:16 +0100
Subject: [PATCH] Zero-copy transfer buffers from the worker to the main thread

---
 src/util.js               | 12 ++++++------
 src/worker/async_proxy.js |  6 ++++--
 src/worker/worker.js      |  2 +-
 test/general/util.js      | 18 ++++--------------
 4 files changed, 15 insertions(+), 23 deletions(-)

diff --git a/src/util.js b/src/util.js
index 9953781d..a526d5e0 100644
--- a/src/util.js
+++ b/src/util.js
@@ -52,19 +52,19 @@ export default {
    * @param  {Object} obj           the options object to be passed to the web worker
    * @returns {Array<ArrayBuffer>}   an array of binary data to be passed
    */
-  getTransferables: function(obj) {
+  getTransferables: function(obj, zero_copy) {
     const transferables = [];
-    util.collectTransferables(obj, transferables);
+    util.collectTransferables(obj, transferables, zero_copy);
     return transferables.length ? transferables : undefined;
   },
 
-  collectTransferables: function(obj, collection) {
+  collectTransferables: function(obj, collection, zero_copy) {
     if (!obj) {
       return;
     }
 
-    if (util.isUint8Array(obj) && collection.indexOf(obj.buffer) === -1) {
-      if (config.zero_copy) {
+    if (util.isUint8Array(obj)) {
+      if (zero_copy && collection.indexOf(obj.buffer) === -1) {
         collection.push(obj.buffer);
       }
       return;
@@ -91,7 +91,7 @@ export default {
         if (Object.prototype.toString.call(value) === '[object MessagePort]') {
           throw new Error("Can't transfer the same stream twice.");
         }
-        util.collectTransferables(value, collection);
+        util.collectTransferables(value, collection, zero_copy);
       });
     }
   },
diff --git a/src/worker/async_proxy.js b/src/worker/async_proxy.js
index 7576c836..35ed6990 100644
--- a/src/worker/async_proxy.js
+++ b/src/worker/async_proxy.js
@@ -22,12 +22,14 @@
  * @see module:openpgp.destroyWorker
  * @see module:worker/worker
  * @requires util
+ * @requires config
  * @requires crypto
  * @requires packet
  * @module worker/async_proxy
  */
 
 import util from '../util.js';
+import config from '../config';
 import crypto from '../crypto';
 import packet from '../packet';
 
@@ -112,7 +114,7 @@ AsyncProxy.prototype.getID = function() {
  */
 AsyncProxy.prototype.seedRandom = async function(workerId, size) {
   const buf = await crypto.random.getRandomBytes(size);
-  this.workers[workerId].postMessage({ event:'seed-random', buf }, util.getTransferables(buf));
+  this.workers[workerId].postMessage({ event:'seed-random', buf }, util.getTransferables(buf, true));
 };
 
 /**
@@ -145,7 +147,7 @@ AsyncProxy.prototype.delegate = function(method, options) {
 
   return new Promise((resolve, reject) => {
     // clone packets (for web worker structured cloning algorithm)
-    this.workers[workerId].postMessage({ id:id, event:method, options:packet.clone.clonePackets(options) }, util.getTransferables(options));
+    this.workers[workerId].postMessage({ id:id, event:method, options:packet.clone.clonePackets(options) }, util.getTransferables(options, config.zero_copy));
     this.workers[workerId].requests++;
 
     // remember to handle parsing cloned packets from worker
diff --git a/src/worker/worker.js b/src/worker/worker.js
index 69df6096..845b1a6b 100644
--- a/src/worker/worker.js
+++ b/src/worker/worker.js
@@ -133,5 +133,5 @@ function delegate(id, method, options) {
  * @param  {Object} event  Contains event type and data
  */
 function response(event) {
-  self.postMessage(event, openpgp.util.getTransferables(event.data));
+  self.postMessage(event, openpgp.util.getTransferables(event.data, true));
 }
diff --git a/test/general/util.js b/test/general/util.js
index 32b672c4..e9162659 100644
--- a/test/general/util.js
+++ b/test/general/util.js
@@ -117,7 +117,6 @@ describe('Util unit tests', function() {
   });
 
   describe('getTransferables', function() {
-    let zero_copyVal;
     const buf1 = new Uint8Array(1);
     const buf2 = new Uint8Array(1);
     const obj = {
@@ -128,27 +127,18 @@ describe('Util unit tests', function() {
         }
       };
 
-    beforeEach(function() {
-      zero_copyVal = openpgp.config.zero_copy;
-      openpgp.config.zero_copy = true;
-    });
-
-    afterEach(function() {
-      openpgp.config.zero_copy = zero_copyVal;
-    });
-
     it('should return undefined when zero_copy is false', function() {
       openpgp.config.zero_copy = false;
-      expect(openpgp.util.getTransferables(obj)).to.be.undefined;
+      expect(openpgp.util.getTransferables(obj, false)).to.be.undefined;
     });
     it('should return undefined for no input', function() {
-      expect(openpgp.util.getTransferables()).to.be.undefined;
+      expect(openpgp.util.getTransferables(undefined, true)).to.be.undefined;
     });
     it('should return undefined for an empty oject', function() {
-      expect(openpgp.util.getTransferables({})).to.be.undefined;
+      expect(openpgp.util.getTransferables({}, true)).to.be.undefined;
     });
     it('should return two buffers', function() {
-      expect(openpgp.util.getTransferables(obj)).to.deep.equal([buf1.buffer, buf2.buffer]);
+      expect(openpgp.util.getTransferables(obj, true)).to.deep.equal([buf1.buffer, buf2.buffer]);
     });
   });