Support JS Array.sort() function for sequence wrappers.

The V8 natve sort implementation calls some functions that are
incompatible with the way sequence wrappers work. In particular,
it calls an internal length() function which does not pass through
the length accessor provided by sequence wrappers, so the sort
function always thinks the array is zero length. Instead, clone the
array prototype and override the sort function with one that is
specific to sequence wrappers.

Task-number: QTBUG-25269
Change-Id: Ic83b9ee0bd3a0707e512f28057f0f99b432fded4
Reviewed-by: Matthew Vogt <matthew.vogt@nokia.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/src/qml/qml/v8/qv8sequencewrapper_p_p.h b/src/qml/qml/v8/qv8sequencewrapper_p_p.h
index cf20aa39fd..e74a5849cc 100644
--- a/src/qml/qml/v8/qv8sequencewrapper_p_p.h
+++ b/src/qml/qml/v8/qv8sequencewrapper_p_p.h
@@ -88,6 +88,7 @@ public:
     virtual v8::Handle<v8::Boolean> indexedDeleter(quint32 index) = 0;
     virtual v8::Handle<v8::Array> indexedEnumerator() = 0;
     virtual v8::Handle<v8::Value> toString() = 0;
+    virtual void sort(v8::Handle<v8::Function> comparer) = 0;
 
     ObjectType objectType;
     QByteArray typeName;
@@ -474,6 +475,25 @@ static QString convertUrlToString(QV8Engine *, const QUrl &v)
                 void *a[] = { &c, 0, &status, &flags }; \
                 QMetaObject::metacall(object, QMetaObject::WriteProperty, propertyIndex, a); \
             } \
+            class CompareFunctor \
+            { \
+            public: \
+                CompareFunctor(QV8Engine *engine, v8::Handle<v8::Function> f) : jsFn(f), eng(engine) {} \
+                bool operator()(SequenceElementType e0, SequenceElementType e1) \
+                { \
+                    v8::Handle<v8::Value> argv[2] = { eng->fromVariant(e0), eng->fromVariant(e1) }; \
+                    v8::Handle<v8::Value> compareValue = jsFn->Call(eng->global(), 2, argv); \
+                    return compareValue->NumberValue() < 0; \
+                } \
+            private: \
+                v8::Handle<v8::Function> jsFn; \
+                QV8Engine *eng; \
+            }; \
+            void sort(v8::Handle<v8::Function> jsCompareFunction) \
+            { \
+                CompareFunctor cf(engine, jsCompareFunction); \
+                qSort(c.begin(), c.end(), cf); \
+            } \
         private: \
             QQmlGuard<QObject> object; \
             int propertyIndex; \