Merge pull request #66 from janekptacijarabaci/js_iterable_closures_1

 Close iterator after error in: Map, Set, WeakMap, WeakSet, Array.from, Promise.{all,race}

7 files changed, 121 insertions, 37 deletions

diff --git a/js/src/builtin/Array.js b/js/src/builtin/Array.js
index 54b47b72f..5ab0b71be 100644
--- a/js/src/builtin/Array.js
+++ b/js/src/builtin/Array.js
@@ -784,7 +784,7 @@ function ArrayKeys() {
     return CreateArrayIterator(this, ITEM_KIND_KEY);
 }
 
-// ES6 draft rev31 (2015/01/15) 22.1.2.1 Array.from(source[, mapfn[, thisArg]]).
+// ES 2017 draft 0f10dba4ad18de92d47d421f378233a2eae8f077 22.1.2.1
 function ArrayFrom(items, mapfn=undefined, thisArg=undefined) {
     // Step 1.
     var C = this;
@@ -795,43 +795,61 @@ function ArrayFrom(items, mapfn=undefined, thisArg=undefined) {
         ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(1, mapfn));
     var T = thisArg;
 
-    // Steps 4-5.
+    // Step 4.
     var usingIterator = GetMethod(items, std_iterator);
 
-    // Step 6.
+    // Step 5.
     if (usingIterator !== undefined) {
-        // Steps 6.a-c.
+        // Steps 5.a-c.
         var A = IsConstructor(C) ? new C() : [];
 
-        // Steps 6.d-e.
+        // Step 5.c.
         var iterator = GetIterator(items, usingIterator);
 
-        // Step 6.f.
+        // Step 5.d.
         var k = 0;
 
-        // Step 6.g.
+        // Step 5.e.
         // These steps cannot be implemented using a for-of loop.
         // See <https://bugs.ecmascript.org/show_bug.cgi?id=2883>.
         while (true) {
-            // Steps 6.g.i-iii.
+            // Step 5.e.i.
+            // Disabled for performance reason.  We won't hit this case on
+            // normal array, since _DefineDataProperty will throw before it.
+            // We could hit this when |A| is a proxy and it ignores
+            // |_DefineDataProperty|, but it happens only after too long loop.
+            /*
+            if (k >= 0x1fffffffffffff) {
+                IteratorCloseThrow(iterator);
+                ThrowTypeError(JSMSG_TOO_LONG_ARRAY);
+            }
+            */
+
+            // Step 5.e.iii.
             var next = callContentFunction(iterator.next, iterator);
             if (!IsObject(next))
                 ThrowTypeError(JSMSG_NEXT_RETURNED_PRIMITIVE);
 
-            // Step 6.g.iv.
+            // Step 5.e.iv.
             if (next.done) {
                 A.length = k;
                 return A;
             }
 
-            // Steps 6.g.v-vi.
+            // Steps 5.e.v.
             var nextValue = next.value;
 
-            // Steps 6.g.vii-viii.
-            var mappedValue = mapping ? callContentFunction(mapfn, thisArg, nextValue, k) : nextValue;
+            // Steps 5.e.vi-vii.
+            try {
+                var mappedValue = mapping ? callContentFunction(mapfn, thisArg, nextValue, k) : nextValue;
 
-            // Steps 6.g.ix-xi.
-            _DefineDataProperty(A, k++, mappedValue);
+                // Steps 5.e.ii (reordered), 5.e.viii.
+                _DefineDataProperty(A, k++, mappedValue);
+            } catch (e) {
+                // Steps 5.e.vi.2, 5.e.ix.
+                IteratorCloseThrow(iterator);
+                throw e;
+            }
         }
     }
 
diff --git a/js/src/builtin/Map.js b/js/src/builtin/Map.js
index 432364614..27a12bfff 100644
--- a/js/src/builtin/Map.js
+++ b/js/src/builtin/Map.js
@@ -40,11 +40,18 @@ function MapConstructorInit(iterable) {
         var nextItem = next.value;
 
         // Step 8.d.
-        if (!IsObject(nextItem))
+        if (!IsObject(nextItem)) {
+            IteratorCloseThrow(iter);
             ThrowTypeError(JSMSG_INVALID_MAP_ITERABLE, "Map");
+        }
 
         // Steps 8.e-j.
-        callContentFunction(adder, map, nextItem[0], nextItem[1]);
+        try {
+            callContentFunction(adder, map, nextItem[0], nextItem[1]);
+        } catch (e) {
+            IteratorCloseThrow(iter);
+            throw e;
+        }
     }
 }
 
diff --git a/js/src/builtin/Promise.cpp b/js/src/builtin/Promise.cpp
index 59c97e529..c781a336d 100644
--- a/js/src/builtin/Promise.cpp
+++ b/js/src/builtin/Promise.cpp
@@ -1369,7 +1369,8 @@ PromiseObject::create(JSContext* cx, HandleObject executor, HandleObject proto /
 
 static MOZ_MUST_USE bool PerformPromiseAll(JSContext *cx, JS::ForOfIterator& iterator,
                                            HandleObject C, HandleObject promiseObj,
-                                           HandleObject resolve, HandleObject reject);
+                                           HandleObject resolve, HandleObject reject,
+                                           bool* done);
 
 // ES2016, 25.4.4.1.
 static bool
@@ -1410,12 +1411,14 @@ Promise_static_all(JSContext* cx, unsigned argc, Value* vp)
     // Step 6 (implicit).
 
     // Step 7.
-    bool result = PerformPromiseAll(cx, iter, C, resultPromise, resolve, reject);
+    bool done;
+    bool result = PerformPromiseAll(cx, iter, C, resultPromise, resolve, reject, &done);
 
     // Step 8.
     if (!result) {
         // Step 8.a.
-        // TODO: implement iterator closing.
+        if (!done)
+            iter.closeThrow();
 
         // Step 8.b.
         return AbruptRejectPromise(cx, args, resultPromise, reject);
@@ -1598,8 +1601,11 @@ RunResolutionFunction(JSContext *cx, HandleObject resolutionFun, HandleValue res
 // ES2016, 25.4.4.1.1.
 static MOZ_MUST_USE bool
 PerformPromiseAll(JSContext *cx, JS::ForOfIterator& iterator, HandleObject C,
-                  HandleObject promiseObj, HandleObject resolve, HandleObject reject)
+                  HandleObject promiseObj, HandleObject resolve, HandleObject reject,
+                  bool* done)
 {
+    *done = false;
+
     RootedObject unwrappedPromiseObj(cx);
     if (IsWrapper(promiseObj)) {
         unwrappedPromiseObj = CheckedUnwrap(promiseObj);
@@ -1666,14 +1672,19 @@ PerformPromiseAll(JSContext *cx, JS::ForOfIterator& iterator, HandleObject C,
     RootedValue rejectFunVal(cx, ObjectOrNullValue(reject));
 
     while (true) {
-        bool done;
-        // Steps a, b, c, e, f, g.
-        if (!iterator.next(&nextValue, &done))
+        // Steps a-c, e-g.
+        if (!iterator.next(&nextValue, done)) {
+            // Steps b, f.
+            *done = true;
+
+            // Steps c, g.
             return false;
+        }
 
         // Step d.
-        if (done) {
+        if (*done) {
             // Step d.i (implicit).
+
             // Step d.ii.
             int32_t remainingCount = dataHolder->decreaseRemainingCount();
 
@@ -1822,7 +1833,8 @@ PromiseAllResolveElementFunction(JSContext* cx, unsigned argc, Value* vp)
 
 static MOZ_MUST_USE bool PerformPromiseRace(JSContext *cx, JS::ForOfIterator& iterator,
                                             HandleObject C, HandleObject promiseObj,
-                                            HandleObject resolve, HandleObject reject);
+                                            HandleObject resolve, HandleObject reject,
+                                            bool* done);
 
 // ES2016, 25.4.4.3.
 static bool
@@ -1863,12 +1875,14 @@ Promise_static_race(JSContext* cx, unsigned argc, Value* vp)
     // Step 6 (implicit).
 
     // Step 7.
-    bool result = PerformPromiseRace(cx, iter, C, resultPromise, resolve, reject);
+    bool done;
+    bool result = PerformPromiseRace(cx, iter, C, resultPromise, resolve, reject, &done);
 
     // Step 8.
     if (!result) {
         // Step 8.a.
-        // TODO: implement iterator closing.
+        if (!done)
+            iter.closeThrow();
 
         // Step 8.b.
         return AbruptRejectPromise(cx, args, resultPromise, reject);
@@ -1882,25 +1896,30 @@ Promise_static_race(JSContext* cx, unsigned argc, Value* vp)
 // ES2016, 25.4.4.3.1.
 static MOZ_MUST_USE bool
 PerformPromiseRace(JSContext *cx, JS::ForOfIterator& iterator, HandleObject C,
-                   HandleObject promiseObj, HandleObject resolve, HandleObject reject)
+                   HandleObject promiseObj, HandleObject resolve, HandleObject reject,
+                   bool* done)
 {
+    *done = false;
     MOZ_ASSERT(C->isConstructor());
     RootedValue CVal(cx, ObjectValue(*C));
 
     RootedValue nextValue(cx);
     RootedValue resolveFunVal(cx, ObjectOrNullValue(resolve));
     RootedValue rejectFunVal(cx, ObjectOrNullValue(reject));
-    bool done;
 
     while (true) {
         // Steps a-c, e-g.
-        if (!iterator.next(&nextValue, &done))
+        if (!iterator.next(&nextValue, done)) {
+            // Steps b, f.
+            *done = true;
+
+            // Steps c, g.
             return false;
+        }
 
         // Step d.
-        if (done) {
-            // Step d.i.
-            // TODO: implement iterator closing.
+        if (*done) {
+            // Step d.i (implicit).
 
             // Step d.ii.
             return true;
diff --git a/js/src/builtin/Set.js b/js/src/builtin/Set.js
index accc70120..c61a49ef8 100644
--- a/js/src/builtin/Set.js
+++ b/js/src/builtin/Set.js
@@ -40,7 +40,12 @@ function SetConstructorInit(iterable) {
         var nextValue = next.value;
 
         // Steps 8.d-e.
-        callContentFunction(adder, set, nextValue);
+        try {
+            callContentFunction(adder, set, nextValue);
+        } catch (e) {
+            IteratorCloseThrow(iter);
+            throw e;
+        }
     }
 }
 
diff --git a/js/src/builtin/Utilities.js b/js/src/builtin/Utilities.js
index bfb1fe7f4..2dece3801 100644
--- a/js/src/builtin/Utilities.js
+++ b/js/src/builtin/Utilities.js
@@ -154,6 +154,29 @@ function GetIterator(obj, method) {
     return iterator;
 }
 
+// ES2017 draft rev 7.4.6.
+// When completion.[[Type]] is throw.
+function IteratorCloseThrow(iter) {
+    // Steps 1-2 (implicit)
+
+    // Step 3.
+    var returnMethod = GetMethod(iter, "return");
+
+    // Step 4 (done in caller).
+    if (returnMethod === undefined)
+        return;
+
+    try {
+        // Step 5.
+        callContentFunction(returnMethod, iter);
+    } catch (e) {
+    }
+
+    // Step 6 (done in caller).
+
+    // Steps 7-9 (skipped).
+}
+
 var _builtinCtorsCache = {__proto__: null};
 
 function GetBuiltinConstructor(builtinName) {
diff --git a/js/src/builtin/WeakMap.js b/js/src/builtin/WeakMap.js
index 066a72bfe..708be8424 100644
--- a/js/src/builtin/WeakMap.js
+++ b/js/src/builtin/WeakMap.js
@@ -40,10 +40,17 @@ function WeakMapConstructorInit(iterable) {
         var nextItem = next.value;
 
         // Step 8.d.
-        if (!IsObject(nextItem))
+        if (!IsObject(nextItem)) {
+            IteratorCloseThrow(iter);
             ThrowTypeError(JSMSG_INVALID_MAP_ITERABLE, "WeakMap");
+        }
 
         // Steps 8.e-j.
-        callContentFunction(adder, map, nextItem[0], nextItem[1]);
+        try {
+            callContentFunction(adder, map, nextItem[0], nextItem[1]);
+        } catch (e) {
+            IteratorCloseThrow(iter);
+            throw e;
+        }
     }
 }
diff --git a/js/src/builtin/WeakSet.js b/js/src/builtin/WeakSet.js
index eb7c2378f..8589f9dc6 100644
--- a/js/src/builtin/WeakSet.js
+++ b/js/src/builtin/WeakSet.js
@@ -40,7 +40,12 @@ function WeakSetConstructorInit(iterable) {
         var nextValue = next.value;
 
         // Steps 8.d-e.
-        callContentFunction(adder, set, nextValue);
+        try {
+            callContentFunction(adder, set, nextValue);
+        } catch (e) {
+            IteratorCloseThrow(iter);
+            throw e;
+        }
     }
 }