Clean up ArrayPrototype::method_join

The code was really convoluted. Calling join() on anything that doesn't
look like an array results in an empty string. Everything else can be
handled by the same algorithm.

While we're at it, clean up IntrinsicTypedArrayPrototype::method_join in
the same way.

Change-Id: I016cd2fe069d23387797a7e58020d40cdb8d60cc
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

1 files changed, 24 insertions, 31 deletions

diff --git a/src/qml/jsruntime/qv4typedarray.cpp b/src/qml/jsruntime/qv4typedarray.cpp
index 7d33167762..893fe06e8e 100644
--- a/src/qml/jsruntime/qv4typedarray.cpp
+++ b/src/qml/jsruntime/qv4typedarray.cpp
@@ -1068,51 +1068,44 @@ ReturnedValue IntrinsicTypedArrayPrototype::method_indexOf(const FunctionObject
     return Encode(-1);
 }
 
-ReturnedValue IntrinsicTypedArrayPrototype::method_join(const FunctionObject *b, const Value *thisObject, const Value *argv, int argc)
+ReturnedValue IntrinsicTypedArrayPrototype::method_join(
+        const FunctionObject *functionObject, const Value *thisObject, const Value *argv, int argc)
 {
-    Scope scope(b);
-    Scoped<TypedArray> v(scope, thisObject);
-    if (!v || v->d()->buffer->isDetachedBuffer())
+    Scope scope(functionObject);
+    Scoped<TypedArray> typedArray(scope, thisObject);
+    if (!typedArray || typedArray->d()->buffer->isDetachedBuffer())
         return scope.engine->throwTypeError();
 
-    uint len = v->length();
-
-    ScopedValue arg(scope, argc ? argv[0] : Value::undefinedValue());
+    // We cannot optimize the resolution of the argument away if length is 0.
+    // It may have side effects.
+    ScopedValue argument(scope, argc ? argv[0] : Value::undefinedValue());
+    const QString separator = argument->isUndefined()
+            ? QStringLiteral(",")
+            : argument->toQString();
 
-    QString r4;
-    if (arg->isUndefined())
-        r4 = QStringLiteral(",");
-    else
-        r4 = arg->toQString();
-
-    const quint32 r2 = len;
-
-    if (!r2)
+    const quint32 length = typedArray->length();
+    if (!length)
         return Encode(scope.engine->newString());
 
-    QString R;
+    QString result;
 
-    //
-    // crazy!
-    //
     ScopedString name(scope, scope.engine->newString(QStringLiteral("0")));
-    ScopedValue r6(scope, v->get(name));
-    if (!r6->isNullOrUndefined())
-        R = r6->toQString();
+    ScopedValue value(scope, typedArray->get(name));
+    if (!value->isNullOrUndefined())
+        result = value->toQString();
 
-    ScopedValue r12(scope);
-    for (quint32 k = 1; k < r2; ++k) {
-        R += r4;
+    for (quint32 i = 1; i < length; ++i) {
+        result += separator;
 
-        name = Value::fromDouble(k).toString(scope.engine);
-        r12 = v->get(name);
+        name = Value::fromDouble(i).toString(scope.engine);
+        value = typedArray->get(name);
         CHECK_EXCEPTION();
 
-        if (!r12->isNullOrUndefined())
-            R += r12->toQString();
+        if (!value->isNullOrUndefined())
+            result += value->toQString();
     }
 
-    return Encode(scope.engine->newString(R));
+    return Encode(scope.engine->newString(result));
 }
 
 ReturnedValue IntrinsicTypedArrayPrototype::method_keys(const FunctionObject *b, const Value *thisObject, const Value *, int)