Call iterator.return when required in destructuring assignments

Array destructuring assignments require a call to iterator.return if
the iterator hasn't been exhausted during destructuring.

Change-Id: I39fe4bc01bef6fb2ad3bda92caf6779fbbddc8e2
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

5 files changed, 43 insertions, 0 deletions

diff --git a/src/qml/jsruntime/qv4engine.cpp b/src/qml/jsruntime/qv4engine.cpp
index 8227fe0184..96855b6155 100644
--- a/src/qml/jsruntime/qv4engine.cpp
+++ b/src/qml/jsruntime/qv4engine.cpp
@@ -270,6 +270,7 @@ ExecutionEngine::ExecutionEngine(QJSEngine *jsEngine)
     jsStrings[String_lastIndex] = newIdentifier(QStringLiteral("lastIndex"));
     jsStrings[String_next] = newIdentifier(QStringLiteral("next"));
     jsStrings[String_done] = newIdentifier(QStringLiteral("done"));
+    jsStrings[String_return] = newIdentifier(QStringLiteral("return"));
 
     jsSymbols[Symbol_hasInstance] = Symbol::create(this, QStringLiteral("@Symbol.hasInstance"));
     jsSymbols[Symbol_isConcatSpreadable] = Symbol::create(this, QStringLiteral("@Symbol.isConcatSpreadable"));
diff --git a/src/qml/jsruntime/qv4engine_p.h b/src/qml/jsruntime/qv4engine_p.h
index 46bf58de07..e90be8e896 100644
--- a/src/qml/jsruntime/qv4engine_p.h
+++ b/src/qml/jsruntime/qv4engine_p.h
@@ -329,6 +329,7 @@ public:
         String_lastIndex,
         String_next,
         String_done,
+        String_return,
 
         NJSStrings
     };
@@ -389,6 +390,7 @@ public:
     String *id_lastIndex() const { return reinterpret_cast<String *>(jsStrings + String_lastIndex); }
     String *id_next() const { return reinterpret_cast<String *>(jsStrings + String_next); }
     String *id_done() const { return reinterpret_cast<String *>(jsStrings + String_done); }
+    String *id_return() const { return reinterpret_cast<String *>(jsStrings + String_return); }
 
     Symbol *symbol_hasInstance() const { return reinterpret_cast<Symbol *>(jsSymbols + Symbol_hasInstance); }
     Symbol *symbol_isConcatSpreadable() const { return reinterpret_cast<Symbol *>(jsSymbols + Symbol_isConcatSpreadable); }
diff --git a/src/qml/jsruntime/qv4runtime.cpp b/src/qml/jsruntime/qv4runtime.cpp
index 650f5c6735..6eff9c50db 100644
--- a/src/qml/jsruntime/qv4runtime.cpp
+++ b/src/qml/jsruntime/qv4runtime.cpp
@@ -737,6 +737,39 @@ ReturnedValue Runtime::method_iteratorNext(ExecutionEngine *engine, const Value
     return Encode(done);
 }
 
+ReturnedValue Runtime::method_iteratorClose(ExecutionEngine *engine, const Value &iterator, const Value &done)
+{
+    Q_ASSERT(iterator.isObject());
+    Q_ASSERT(done.isBoolean());
+    if (done.booleanValue())
+        return Encode::undefined();
+
+    Scope scope(engine);
+    bool hadException = engine->hasException;
+    ScopedValue e(scope);
+    if (hadException) {
+        e = *engine->exceptionValue;
+        engine->hasException = false;
+    }
+    ScopedFunctionObject f(scope, static_cast<const Object &>(iterator).get(engine->id_return()));
+    ScopedObject o(scope);
+    if (f) {
+        JSCallData cData(scope, 0, nullptr, &iterator);
+        o = f->call(cData);
+    }
+    if (hadException || !f) {
+        *engine->exceptionValue = e;
+        engine->hasException = hadException;
+        return Encode::undefined();
+    }
+    if (engine->hasException)
+        return Encode::undefined();
+
+    if (!o)
+        return engine->throwTypeError();
+    return Encode::undefined();
+}
+
 ReturnedValue Runtime::method_destructureRestElement(ExecutionEngine *engine, const Value &iterator)
 {
     Q_ASSERT(iterator.isObject());
diff --git a/src/qml/jsruntime/qv4runtimeapi_p.h b/src/qml/jsruntime/qv4runtimeapi_p.h
index a22a053cd1..266dc36680 100644
--- a/src/qml/jsruntime/qv4runtimeapi_p.h
+++ b/src/qml/jsruntime/qv4runtimeapi_p.h
@@ -147,6 +147,7 @@ struct ExceptionCheck<void (*)(QV4::NoThrowEngine *, A, B, C)> {
     /* for-in, for-of and array destructuring */ \
     F(ReturnedValue, getIterator, (ExecutionEngine *engine, const Value &in, int iterator)) \
     F(ReturnedValue, iteratorNext, (ExecutionEngine *engine, const Value &iterator, Value *value)) \
+    F(ReturnedValue, iteratorClose, (ExecutionEngine *engine, const Value &iterator, const Value &done)) \
     F(ReturnedValue, destructureRestElement, (ExecutionEngine *engine, const Value &iterator)) \
     \
     /* unary operators */ \
diff --git a/src/qml/jsruntime/qv4vme_moth.cpp b/src/qml/jsruntime/qv4vme_moth.cpp
index 17ed1ae044..f39fd39a98 100644
--- a/src/qml/jsruntime/qv4vme_moth.cpp
+++ b/src/qml/jsruntime/qv4vme_moth.cpp
@@ -965,6 +965,12 @@ QV4::ReturnedValue VME::interpret(CppStackFrame &frame, const uchar *code)
         CHECK_EXCEPTION;
     MOTH_END_INSTR(IteratorNext)
 
+    MOTH_BEGIN_INSTR(IteratorClose)
+        STORE_ACC();
+        acc = Runtime::method_iteratorClose(engine, accumulator, STACK_VALUE(done));
+        CHECK_EXCEPTION;
+    MOTH_END_INSTR(IteratorClose)
+
     MOTH_BEGIN_INSTR(DestructureRestElement)
         STORE_ACC();
         acc = Runtime::method_destructureRestElement(engine, ACC);