Implement Microtask Delivery Queue

R=rossberg@chromium.org, rossberg
BUG=

Review URL: https://codereview.chromium.org/131413008

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19084 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/object-observe.js

@@ -63,6 +63,7 @@ if (IS_UNDEFINED(observationState.callbackInfoMap)) {
   observationState.notifierObjectInfoMap = %ObservationWeakMapCreate();
   observationState.pendingObservers = null;
   observationState.nextCallbackPriority = 0;
+  observationState.microtaskScheduled = false;
 }
 
 function ObservationWeakMap(map) {
@@ -394,7 +395,7 @@ function ObserverEnqueueIfActive(observer, objectInfo, changeRecord,
     observationState.pendingObservers = nullProtoObject();
   observationState.pendingObservers[callbackInfo.priority] = callback;
   callbackInfo.push(changeRecord);
-  %SetMicrotaskPending(true);
+  EnqueueObserveMicrotask();
 }
 
 function ObjectInfoEnqueueExternalChangeRecord(objectInfo, changeRecord, type) {
@@ -575,6 +576,7 @@ function ObjectDeliverChangeRecords(callback) {
 }
 
 function ObserveMicrotaskRunner() {
+  observationState.microtaskScheduled = false;
   var pendingObservers = observationState.pendingObservers;
   if (pendingObservers) {
     observationState.pendingObservers = null;
@@ -583,7 +585,15 @@ function ObserveMicrotaskRunner() {
     }
   }
 }
-RunMicrotasks.runners.push(ObserveMicrotaskRunner);
+
+function EnqueueObserveMicrotask() {
+  if (observationState.microtaskScheduled)
+    return;
+
+  RunMicrotasks.queue.push(ObserveMicrotaskRunner);
+  %SetMicrotaskPending(true);
+  observationState.microtaskScheduled = true;
+}
 
 function SetupObjectObserve() {
   %CheckIsBootstrapping();

src/promise.js

@@ -173,37 +173,29 @@ function PromiseCatch(onReject) {
 }
 
 function PromiseEnqueue(value, tasks) {
-  promiseEvents.push(value, tasks);
+  RunMicrotasks.queue.push(function() {
+    for (var i = 0; i < tasks.length; i += 2) {
+      PromiseHandle(value, tasks[i], tasks[i + 1])
+    }
+  });
+
   %SetMicrotaskPending(true);
 }
 
-function PromiseMicrotaskRunner() {
-  var events = promiseEvents;
-  if (events.length > 0) {
-    promiseEvents = new InternalArray;
-    for (var i = 0; i < events.length; i += 2) {
-      var value = events[i];
-      var tasks = events[i + 1];
-      for (var j = 0; j < tasks.length; j += 2) {
-        var handler = tasks[j];
-        var deferred = tasks[j + 1];
-        try {
-          var result = handler(value);
-          if (result === deferred.promise)
-            throw MakeTypeError('promise_cyclic', [result]);
-          else if (IsPromise(result))
-            result.chain(deferred.resolve, deferred.reject);
-          else
-            deferred.resolve(result);
-        } catch(e) {
-          // TODO(rossberg): perhaps log uncaught exceptions below.
-          try { deferred.reject(e) } catch(e) {}
-        }
-      }
-    }
+function PromiseHandle(value, handler, deferred) {
+  try {
+    var result = handler(value);
+    if (result === deferred.promise)
+      throw MakeTypeError('promise_cyclic', [result]);
+    else if (IsPromise(result))
+      result.chain(deferred.resolve, deferred.reject);
+    else
+      deferred.resolve(result);
+  } catch(e) {
+    // TODO(rossberg): perhaps log uncaught exceptions below.
+    try { deferred.reject(e) } catch(e) {}
   }
 }
-RunMicrotasks.runners.push(PromiseMicrotaskRunner);
 
 
 // Multi-unwrapped chaining with thenable coercion.

src/runtime.cc

@@ -14592,6 +14592,14 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_SetMicrotaskPending) {
 }
 
 
+RUNTIME_FUNCTION(MaybeObject*, Runtime_RunMicrotasks) {
+  HandleScope scope(isolate);
+  ASSERT(args.length() == 0);
+  Execution::RunMicrotasks(isolate);
+  return isolate->heap()->undefined_value();
+}
+
+
 RUNTIME_FUNCTION(MaybeObject*, Runtime_GetObservationState) {
   SealHandleScope shs(isolate);
   ASSERT(args.length() == 0);

src/runtime.h

@@ -351,6 +351,7 @@ namespace internal {
   \
   /* Harmony events */ \
   F(SetMicrotaskPending, 1, 1) \
+  F(RunMicrotasks, 0, 1) \
   \
   /* Harmony observe */ \
   F(IsObserved, 1, 1) \

src/v8natives.js

@@ -1898,10 +1898,15 @@ SetUpFunction();
 // Eventually, we should move to a real event queue that allows to maintain
 // relative ordering of different kinds of tasks.
 
-RunMicrotasks.runners = new InternalArray;
+RunMicrotasks.queue = new InternalArray;
 
 function RunMicrotasks() {
   while (%SetMicrotaskPending(false)) {
-    for (var i in RunMicrotasks.runners) RunMicrotasks.runners[i]();
+    var microtasks = RunMicrotasks.queue;
+    RunMicrotasks.queue = new InternalArray;
+
+    for (var i = 0; i < microtasks.length; i++) {
+      microtasks[i]();
+    }
   }
 }

test/cctest/cctest.gyp

@@ -88,6 +88,7 @@
         'test-liveedit.cc',
         'test-lockers.cc',
         'test-log.cc',
+        'test-microtask-delivery.cc',
         'test-mark-compact.cc',
         'test-mementos.cc',
         'test-mutex.cc',

test/cctest/test-microtask-delivery.cc

+// Copyright 2012 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "v8.h"
+
+#include "cctest.h"
+
+using namespace v8;
+namespace i = v8::internal;
+
+namespace {
+class HarmonyIsolate {
+ public:
+  HarmonyIsolate() {
+    i::FLAG_harmony_observation = true;
+    i::FLAG_harmony_promises = true;
+    isolate_ = Isolate::New();
+    isolate_->Enter();
+  }
+
+  ~HarmonyIsolate() {
+    isolate_->Exit();
+    isolate_->Dispose();
+  }
+
+  Isolate* GetIsolate() const { return isolate_; }
+
+ private:
+  Isolate* isolate_;
+};
+}
+
+
+TEST(MicrotaskDeliverySimple) {
+  HarmonyIsolate isolate;
+  HandleScope scope(isolate.GetIsolate());
+  LocalContext context(isolate.GetIsolate());
+  CompileRun(
+      "var ordering = [];"
+      "var resolver = {};"
+      "function handler(resolve) { resolver.resolve = resolve; }"
+      "var obj = {};"
+      "var observeOrders = [1, 4];"
+      "function observer() {"
+        "ordering.push(observeOrders.shift());"
+        "resolver.resolve();"
+      "}"
+      "var p = new Promise(handler);"
+      "p.then(function() {"
+        "ordering.push(2);"
+      "}).then(function() {"
+        "ordering.push(3);"
+        "obj.id++;"
+        "return new Promise(handler);"
+      "}).then(function() {"
+        "ordering.push(5);"
+      "}).then(function() {"
+        "ordering.push(6);"
+      "});"
+      "Object.observe(obj, observer);"
+      "obj.id = 1;");
+  CHECK_EQ(6, CompileRun("ordering.length")->Int32Value());
+  CHECK_EQ(1, CompileRun("ordering[0]")->Int32Value());
+  CHECK_EQ(2, CompileRun("ordering[1]")->Int32Value());
+  CHECK_EQ(3, CompileRun("ordering[2]")->Int32Value());
+  CHECK_EQ(4, CompileRun("ordering[3]")->Int32Value());
+  CHECK_EQ(5, CompileRun("ordering[4]")->Int32Value());
+  CHECK_EQ(6, CompileRun("ordering[5]")->Int32Value());
+}

test/mjsunit/fuzz-natives-part3.js

@@ -216,7 +216,10 @@ var knownProblems = {
   "DataViewInitialize":true,
   "DataViewGetBuffer": true,
   "DataViewGetByteLength": true,
-  "DataViewGetByteOffset": true
+  "DataViewGetByteOffset": true,
+
+  // Only ever called internally.
+  "RunMicrotasks": true
 };
 
 var currentlyUncallable = {

test/mjsunit/harmony/microtask-delivery.js

+// Copyright 2012 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Flags: --harmony-observation --harmony-promises --allow-natives-syntax
+
+var ordering = [];
+function reset() {
+  ordering = [];
+}
+
+function assertArrayValues(expected, actual) {
+  assertEquals(expected.length, actual.length);
+  for (var i = 0; i < expected.length; i++) {
+    assertEquals(expected[i], actual[i]);
+  }
+}
+
+function assertOrdering(expected) {
+  %RunMicrotasks();
+  assertArrayValues(expected, ordering);
+}
+
+function newPromise(id, fn) {
+  var r;
+  var t = 1;
+  var promise = new Promise(function(resolve) {
+    r = resolve;
+    if (fn) fn();
+  });
+
+  var next = promise.then(function(value) {
+    ordering.push('p' + id);
+    return value;
+  });
+
+  return {
+    resolve: r,
+    then: function(fn) {
+      next = next.then(function(value) {
+        ordering.push('p' + id + ':' + t++);
+        return fn ? fn(value) : value;
+      });
+
+      return this;
+    }
+  };
+}
+
+function newObserver(id, fn, obj) {
+  var observer = {
+    value: 1,
+    recordCounts: []
+  };
+
+  Object.observe(observer, function(records) {
+    ordering.push('o' + id);
+    observer.recordCounts.push(records.length);
+    if (fn) fn();
+  });
+
+  return observer;
+}
+
+
+(function PromiseThens() {
+  reset();
+
+  var p1 = newPromise(1).then();
+  var p2 = newPromise(2).then();
+
+  p1.resolve();
+  p2.resolve();
+
+  assertOrdering(['p1', 'p2', 'p1:1', 'p2:1']);
+})();
+
+
+(function ObserversBatch() {
+  reset();
+
+  var p1 = newPromise(1);
+  var p2 = newPromise(2);
+  var p3 = newPromise(3);
+
+  var ob1 = newObserver(1);
+  var ob2 = newObserver(2, function() {
+    ob3.value++;
+    p3.resolve();
+    ob1.value++;
+  });
+  var ob3 = newObserver(3);
+
+  p1.resolve();
+  ob1.value++;
+  p2.resolve();
+  ob2.value++;
+
+  assertOrdering(['p1', 'o1', 'o2', 'p2', 'o1', 'o3', 'p3']);
+  assertArrayValues([1, 1], ob1.recordCounts);
+  assertArrayValues([1], ob2.recordCounts);
+  assertArrayValues([1], ob3.recordCounts);
+})();
+
+
+(function ObserversGetAllRecords() {
+  reset();
+
+  var p1 = newPromise(1);
+  var p2 = newPromise(2);
+  var ob1 = newObserver(1, function() {
+    ob2.value++;
+  });
+  var ob2 = newObserver(2);
+
+  p1.resolve();
+  ob1.value++;
+  p2.resolve();
+  ob2.value++;
+
+  assertOrdering(['p1', 'o1', 'o2', 'p2']);
+  assertArrayValues([1], ob1.recordCounts);
+  assertArrayValues([2], ob2.recordCounts);
+})();
+
+
+(function NewObserverDeliveryGetsNewMicrotask() {
+  reset();
+
+  var p1 = newPromise(1);
+  var p2 = newPromise(2);
+  var ob1 = newObserver(1);
+  var ob2 = newObserver(2, function() {
+    ob1.value++;
+  });
+
+  p1.resolve();
+  ob1.value++;
+  p2.resolve();
+  ob2.value++;
+
+  assertOrdering(['p1', 'o1', 'o2', 'p2', 'o1']);
+  assertArrayValues([1, 1], ob1.recordCounts);
+  assertArrayValues([1], ob2.recordCounts);
+})();