Added no argument constructor support to external arrays.

src/d8.cc

Index: src/d8.cc
===================================================================
--- src/d8.cc	(revision 10785)
+++ src/d8.cc	(working copy)
@@ -330,16 +330,14 @@
   }
   ASSERT(element_size == 1 || element_size == 2 || element_size == 4 ||
          element_size == 8);
-  if (args.Length() == 0) {
-    return ThrowException(
-        String::New("Array constructor must have at least one "
-                    "parameter."));
-  }
+
   bool first_arg_is_array_buffer =
+      args.Length() > 0 &&
       args[0]->IsObject() &&
       args[0]->ToObject()->Get(
           String::New(kArrayBufferMarkerPropName))->IsTrue();
   // Currently, only the following constructors are supported:
+  //   TypedArray()
   //   TypedArray(unsigned long length)
   //   TypedArray(ArrayBuffer buffer,
   //              optional unsigned long byteOffset,
@@ -347,16 +345,21 @@
   if (args.Length() > 3) {
     return ThrowException(
         String::New("Array constructor from ArrayBuffer must "
-                    "have 1-3 parameters."));
+                    "have 0-3 parameters."));
   }
 
-  Local<Value> length_value = (args.Length() < 3)
-      ? (first_arg_is_array_buffer
-         ? args[0]->ToObject()->Get(String::New("length"))
-         : args[0])
-      : args[2];
-  size_t length = convertToUint(length_value, &try_catch);
-  if (try_catch.HasCaught()) return try_catch.Exception();
+  size_t length;
+  if (args.Length() > 0) {
+    Local<Value> length_value = (args.Length() < 3)
+        ? (first_arg_is_array_buffer
+           ? args[0]->ToObject()->Get(String::New("length"))
+           : args[0])
+        : args[2];
+    length = convertToUint(length_value, &try_catch);
+    if (try_catch.HasCaught()) return try_catch.Exception();
+  } else {
+    length = 0;
+  }
 
   void* data = NULL;
   size_t offset = 0;
@@ -428,7 +431,7 @@
   Persistent<Object> persistent_array = Persistent<Object>::New(array);
   persistent_array.MakeWeak(data, ExternalArrayWeakCallback);
   persistent_array.MarkIndependent();
-  if (data == NULL && length != 0) {
+  if (data == NULL) {
     data = calloc(length, element_size);
     if (data == NULL) {
       return ThrowException(String::New("Memory allocation failed."));