Auto merge of #438 - ferjm:issharedarraybuffer, r=jdm

Add function to tell whether a TypedArray underlying buffer is shared

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Author: bors-servo

src/typedarray.rs

@@ -31,6 +31,7 @@ use jsapi::JS_GetFloat64ArrayData;
 use jsapi::JS_GetInt16ArrayData;
 use jsapi::JS_GetInt32ArrayData;
 use jsapi::JS_GetInt8ArrayData;
+use jsapi::JS_GetTypedArraySharedness;
 use jsapi::JS_GetUint16ArrayData;
 use jsapi::JS_GetUint32ArrayData;
 use jsapi::JS_GetUint8ArrayData;
@@ -206,6 +207,12 @@ impl<T: TypedArrayElement, S: JSObjectStorage> TypedArray<T, S> {
         let (pointer, length) = self.data();
         slice::from_raw_parts_mut(pointer, length as usize)
     }
+
+    /// Return a boolean flag which denotes whether the underlying buffer
+    /// is a SharedArrayBuffer.
+    pub fn is_shared(&self) -> bool {
+        unsafe { JS_GetTypedArraySharedness(self.object.as_raw()) }
+    }
 }
 
 impl<T: TypedArrayElementCreator + TypedArrayElement, S: JSObjectStorage> TypedArray<T, S> {

tests/typedarray.rs

@@ -77,5 +77,8 @@ fn typedarray() {
 
         typedarray!(in(cx) let view: ArrayBufferView = rval.get());
         assert_eq!(view.unwrap().get_array_type(), Type::Uint32);
+
+        typedarray!(in(cx) let view: ArrayBufferView = rval.get());
+        assert_eq!(view.unwrap().is_shared(), false);
     }
 }