Reland Create JSPromise (patchset #16 id:300001 of https://codereview.chromium.org/2536463002/ )"

src/js/promise.js

Index: src/js/promise.js
diff --git a/src/js/promise.js b/src/js/promise.js
index 25c8beaa9e0aef86dd966faa3af89d8e342c04a3..b78f68c4f71c367365a8a149803c3091a9e55f75 100644
--- a/src/js/promise.js
+++ b/src/js/promise.js
@@ -20,12 +20,6 @@ var promiseForwardingHandlerSymbol =
     utils.ImportNow("promise_forwarding_handler_symbol");
 var promiseHasHandlerSymbol =
     utils.ImportNow("promise_has_handler_symbol");
-var promiseRejectReactionsSymbol =
-    utils.ImportNow("promise_reject_reactions_symbol");
-var promiseFulfillReactionsSymbol =
-    utils.ImportNow("promise_fulfill_reactions_symbol");
-var promiseDeferredReactionSymbol =
-    utils.ImportNow("promise_deferred_reaction_symbol");
 var promiseHandledHintSymbol =
     utils.ImportNow("promise_handled_hint_symbol");
 var promiseRawSymbol = utils.ImportNow("promise_raw_symbol");
@@ -36,6 +30,7 @@ var speciesSymbol = utils.ImportNow("species_symbol");
 var toStringTagSymbol = utils.ImportNow("to_string_tag_symbol");
 var ObjectHasOwnProperty;
 var GlobalPromise = global.Promise;
+var PromiseThen = GlobalPromise.prototype.then;
 
 utils.Import(function(from) {
   ObjectHasOwnProperty = from.ObjectHasOwnProperty;
@@ -46,42 +41,6 @@ utils.Import(function(from) {
 
 // Core functionality.
 
-function PromiseSet(promise, status, value) {
-  SET_PRIVATE(promise, promiseStateSymbol, status);
-  SET_PRIVATE(promise, promiseResultSymbol, value);
-
-  // There are 3 possible states for the resolve, reject symbols when we add
-  // a new callback --
-  // 1) UNDEFINED -- This is the zero state where there is no callback
-  // registered. When we see this state, we directly attach the callbacks to
-  // the symbol.
-  // 2) !IS_ARRAY -- There is a single callback directly attached to the
-  // symbols. We need to create a new array to store additional callbacks.
-  // 3) IS_ARRAY -- There are multiple callbacks already registered,
-  // therefore we can just push the new callback to the existing array.
-  SET_PRIVATE(promise, promiseFulfillReactionsSymbol, UNDEFINED);
-  SET_PRIVATE(promise, promiseRejectReactionsSymbol, UNDEFINED);
-
-  // This symbol is used only when one deferred needs to be attached. When more
-  // than one deferred need to be attached the promise, we attach them directly
-  // to the promiseFulfillReactionsSymbol and promiseRejectReactionsSymbol and
-  // reset this back to UNDEFINED.
-  SET_PRIVATE(promise, promiseDeferredReactionSymbol, UNDEFINED);
-
-  return promise;
-}
-
-function PromiseCreateAndSet(status, value) {
-  var promise = %promise_internal_constructor();
-  // If debug is active, notify about the newly created promise first.
-  if (DEBUG_IS_ACTIVE) PromiseSet(promise, kPending, UNDEFINED);
-  return PromiseSet(promise, status, value);
-}
-
-function PromiseInit(promise) {
-  return PromiseSet(promise, kPending, UNDEFINED);
-}
-
 function PromiseHandle(value, handler, deferred) {
   var debug_is_active = DEBUG_IS_ACTIVE;
   try {
@@ -98,7 +57,6 @@ function PromiseHandle(value, handler, deferred) {
         // Pass false for debugEvent so .then chaining or throwaway promises
         // in async functions do not trigger redundant ExceptionEvents.
         %PromiseReject(deferred.promise, exception, false);
-        PromiseSet(deferred.promise, kRejected, exception);
       } else {
         %_Call(deferred.reject, UNDEFINED, exception);
       }
@@ -134,34 +92,6 @@ function PromiseDebugGetInfo(deferreds, status) {
   return [id, name];
 }
 
-function PromiseAttachCallbacks(promise, deferred, onResolve, onReject) {
-  var maybeResolveCallbacks =
-      GET_PRIVATE(promise, promiseFulfillReactionsSymbol);
-  if (IS_UNDEFINED(maybeResolveCallbacks)) {
-    SET_PRIVATE(promise, promiseFulfillReactionsSymbol, onResolve);
-    SET_PRIVATE(promise, promiseRejectReactionsSymbol, onReject);
-    SET_PRIVATE(promise, promiseDeferredReactionSymbol, deferred);
-  } else if (!IS_ARRAY(maybeResolveCallbacks)) {
-    var resolveCallbacks = new InternalArray();
-    var rejectCallbacks = new InternalArray();
-    var existingDeferred = GET_PRIVATE(promise, promiseDeferredReactionSymbol);
-
-    resolveCallbacks.push(
-        maybeResolveCallbacks, existingDeferred, onResolve, deferred);
-    rejectCallbacks.push(GET_PRIVATE(promise, promiseRejectReactionsSymbol),
-                         existingDeferred,
-                         onReject,
-                         deferred);
-
-    SET_PRIVATE(promise, promiseFulfillReactionsSymbol, resolveCallbacks);
-    SET_PRIVATE(promise, promiseRejectReactionsSymbol, rejectCallbacks);
-    SET_PRIVATE(promise, promiseDeferredReactionSymbol, UNDEFINED);
-  } else {
-    maybeResolveCallbacks.push(onResolve, deferred);
-    GET_PRIVATE(promise, promiseRejectReactionsSymbol).push(onReject, deferred);
-  }
-}
-
 function PromiseIdResolveHandler(x) { return x; }
 function PromiseIdRejectHandler(r) { %_ReThrow(r); }
 SET_PRIVATE(PromiseIdRejectHandler, promiseForwardingHandlerSymbol, true);
@@ -171,8 +101,9 @@ SET_PRIVATE(PromiseIdRejectHandler, promiseForwardingHandlerSymbol, true);
 
 // For bootstrapper.
 
+// This is used by utils and v8-extras.
 function PromiseCreate() {
-  return PromiseInit(%promise_internal_constructor());
+  return %promise_internal_constructor();
 }
 
 // ES#sec-promise-resolve-functions
@@ -181,7 +112,6 @@ function ResolvePromise(promise, resolution) {
   if (resolution === promise) {
     var exception = %make_type_error(kPromiseCyclic, resolution);
     %PromiseReject(promise, exception, true);
-    PromiseSet(promise, kRejected, exception);
     return;
   }
   if (IS_RECEIVER(resolution)) {
@@ -190,7 +120,6 @@ function ResolvePromise(promise, resolution) {
       var then = resolution.then;
     } catch (e) {
       %PromiseReject(promise, e, true);
-      PromiseSet(promise, kRejected, e);
       return;
     }
 
@@ -198,18 +127,16 @@ function ResolvePromise(promise, resolution) {
     // rejected, shortcircuit the resolution procedure by directly
     // reusing the value from the promise.
     if (%is_promise(resolution) && then === PromiseThen) {
-      var thenableState = GET_PRIVATE(resolution, promiseStateSymbol);
+      var thenableState = %PromiseStatus(resolution);
       if (thenableState === kFulfilled) {
         // This goes inside the if-else to save one symbol lookup in
         // the slow path.
-        var thenableValue = GET_PRIVATE(resolution, promiseResultSymbol);
-        %PromiseFulfill(promise, kFulfilled, thenableValue,
-                       promiseFulfillReactionsSymbol);
-        PromiseSet(promise, kFulfilled, thenableValue);
+        var thenableValue = %PromiseResult(resolution);
+        %PromiseFulfill(promise, kFulfilled, thenableValue);
         SET_PRIVATE(promise, promiseHasHandlerSymbol, true);
         return;
       } else if (thenableState === kRejected) {
-        var thenableValue = GET_PRIVATE(resolution, promiseResultSymbol);
+        var thenableValue = %PromiseResult(resolution);
         if (!HAS_DEFINED_PRIVATE(resolution, promiseHasHandlerSymbol)) {
           // Promise has already been rejected, but had no handler.
           // Revoke previously triggered reject event.
@@ -217,7 +144,6 @@ function ResolvePromise(promise, resolution) {
         }
         // Don't cause a debug event as this case is forwarding a rejection
         %PromiseReject(promise, thenableValue, false);
-        PromiseSet(promise, kRejected, thenableValue);
         SET_PRIVATE(resolution, promiseHasHandlerSymbol, true);
         return;
       }
@@ -232,21 +158,17 @@ function ResolvePromise(promise, resolution) {
       return;
     }
   }
-  %PromiseFulfill(promise, kFulfilled, resolution,
-                  promiseFulfillReactionsSymbol);
-  PromiseSet(promise, kFulfilled, resolution);
+  %PromiseFulfill(promise, kFulfilled, resolution);
 }
 
 // Only used by async-await.js
 function RejectPromise(promise, reason, debugEvent) {
   %PromiseReject(promise, reason, debugEvent);
-  PromiseSet(promise, kRejected, reason);
 }
 
 // Export to bindings
 function DoRejectPromise(promise, reason) {
   %PromiseReject(promise, reason, true);
-  PromiseSet(promise, kRejected, reason);
 }
 
 // The resultCapability.promise is only ever fulfilled internally,
@@ -254,7 +176,7 @@ function DoRejectPromise(promise, reason) {
 // calling them multiple times.
 function CreateInternalPromiseCapability() {
   return {
-    promise: PromiseCreate(),
+    promise: %promise_internal_constructor(),
     resolve: UNDEFINED,
     reject: UNDEFINED
   };
@@ -265,7 +187,7 @@ function CreateInternalPromiseCapability() {
 function NewPromiseCapability(C, debugEvent) {
   if (C === GlobalPromise) {
     // Optimized case, avoid extra closure.
-    var promise = PromiseCreate();
+    var promise = %promise_internal_constructor();
     // TODO(gsathya): Remove container for callbacks when this is
     // moved to CPP/TF.
     var callbacks = %create_resolving_functions(promise, debugEvent);
@@ -298,7 +220,7 @@ function PromiseReject(r) {
   }
   if (this === GlobalPromise) {
     // Optimized case, avoid extra closure.
-    var promise = PromiseCreateAndSet(kRejected, r);
+    var promise = %promise_create_and_set(kRejected, r);
     // Trigger debug events if the debugger is on, as Promise.reject is
     // equivalent to throwing an exception directly.
     %PromiseRejectEventFromStack(promise, r);
@@ -310,55 +232,6 @@ function PromiseReject(r) {
   }
 }
 
-function PerformPromiseThen(promise, onResolve, onReject, resultCapability) {
-  if (!IS_CALLABLE(onResolve)) onResolve = PromiseIdResolveHandler;
-  if (!IS_CALLABLE(onReject)) onReject = PromiseIdRejectHandler;
-
-  var status = GET_PRIVATE(promise, promiseStateSymbol);
-  switch (status) {
-    case kPending:
-      PromiseAttachCallbacks(promise, resultCapability, onResolve, onReject);
-      break;
-    case kFulfilled:
-      %EnqueuePromiseReactionJob(GET_PRIVATE(promise, promiseResultSymbol),
-                                 onResolve, resultCapability, kFulfilled);
-      break;
-    case kRejected:
-      if (!HAS_DEFINED_PRIVATE(promise, promiseHasHandlerSymbol)) {
-        // Promise has already been rejected, but had no handler.
-        // Revoke previously triggered reject event.
-        %PromiseRevokeReject(promise);
-      }
-      %EnqueuePromiseReactionJob(GET_PRIVATE(promise, promiseResultSymbol),
-                                 onReject, resultCapability, kRejected);
-      break;
-  }
-
-  // Mark this promise as having handler.
-  SET_PRIVATE(promise, promiseHasHandlerSymbol, true);
-  return resultCapability.promise;
-}
-
-// ES#sec-promise.prototype.then
-// Promise.prototype.then ( onFulfilled, onRejected )
-// Multi-unwrapped chaining with thenable coercion.
-function PromiseThen(onResolve, onReject) {
-  if (!%is_promise(this)) {
-    throw %make_type_error(kNotAPromise, this);
-  }
-
-  var constructor = SpeciesConstructor(this, GlobalPromise);
-  var resultCapability;
-  if (constructor === GlobalPromise) {
-    resultCapability = CreateInternalPromiseCapability();
-  } else {
-    // Pass false for debugEvent so .then chaining does not trigger
-    // redundant ExceptionEvents.
-    resultCapability = NewPromiseCapability(constructor, false);
-  }
-  return PerformPromiseThen(this, onResolve, onReject, resultCapability);
-}
-
 // ES#sec-promise.prototype.catch
 // Promise.prototype.catch ( onRejected )
 function PromiseCatch(onReject) {
@@ -377,7 +250,7 @@ function PromiseResolve(x) {
 
   // Avoid creating resolving functions.
   if (this === GlobalPromise) {
-    var promise = PromiseCreate();
+    var promise = %promise_internal_constructor();
     ResolvePromise(promise, x);
     return promise;
   }
@@ -520,8 +393,10 @@ function PromiseHasUserDefinedRejectHandlerRecursive(promise) {
     return true;
   }
 
-  var queue = GET_PRIVATE(promise, promiseRejectReactionsSymbol);
-  var deferred = GET_PRIVATE(promise, promiseDeferredReactionSymbol);
+  if (!%is_promise(promise)) return false;
+
+  var queue = %PromiseRejectReactions(promise);
+  var deferred = %PromiseDeferred(promise);
 
   if (IS_UNDEFINED(queue)) return false;
 
@@ -529,8 +404,8 @@ function PromiseHasUserDefinedRejectHandlerRecursive(promise) {
     return PromiseHasUserDefinedRejectHandlerCheck(queue, deferred);
   }
 
-  for (var i = 0; i < queue.length; i += 2) {
-    if (PromiseHasUserDefinedRejectHandlerCheck(queue[i], queue[i + 1])) {
+  for (var i = 0; i < queue.length; i++) {
+    if (PromiseHasUserDefinedRejectHandlerCheck(queue[i], deferred[i])) {
       return true;
     }
   }
@@ -568,7 +443,6 @@ utils.InstallFunctions(GlobalPromise, DONT_ENUM, [
 utils.InstallGetter(GlobalPromise, speciesSymbol, PromiseSpecies);
 
 utils.InstallFunctions(GlobalPromise.prototype, DONT_ENUM, [
-  "then", PromiseThen,
   "catch", PromiseCatch
 ]);
 
@@ -582,7 +456,11 @@ utils.InstallFunctions(GlobalPromise.prototype, DONT_ENUM, [
   "promise_resolve", ResolvePromise,
   "promise_then", PromiseThen,
   "promise_handle", PromiseHandle,
-  "promise_debug_get_info", PromiseDebugGetInfo
+  "promise_debug_get_info", PromiseDebugGetInfo,
+  "new_promise_capability", NewPromiseCapability,
+  "internal_promise_capability", CreateInternalPromiseCapability,
+  "promise_id_resolve_handler", PromiseIdResolveHandler,
+  "promise_id_reject_handler", PromiseIdRejectHandler
 ]);
 
 // This allows extras to create promises quickly without building extra
@@ -600,7 +478,6 @@ utils.Export(function(to) {
   to.PromiseThen = PromiseThen;
 
   to.CreateInternalPromiseCapability = CreateInternalPromiseCapability;
-  to.PerformPromiseThen = PerformPromiseThen;
   to.ResolvePromise = ResolvePromise;
   to.RejectPromise = RejectPromise;
 });