Implement Function.prototype.bind (ES5 15.3.4.5).

Please note that we do not implement correctly the setting of caller
and arguments on the returned objects, since we already have these
properties on function objects (and they are non-configurable).

Also corrects indention in DefineOwnProperty.

Review URL: http://codereview.chromium.org/3046010

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5124 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/runtime.cc

@@ -6751,6 +6751,27 @@ static Object* Runtime_NewClosure(Arguments args) {
   return *result;
 }
 
+static Object* Runtime_NewObjectFromBound(Arguments args) {
+   HandleScope scope;
+   ASSERT(args.length() == 2);
+   CONVERT_ARG_CHECKED(JSFunction, function, 0);
+   CONVERT_ARG_CHECKED(JSArray, params, 1);
+
+   FixedArray* fixed = FixedArray::cast(params->elements());
+
+   bool exception = false;
+   Object*** param_data = NewArray<Object**>(fixed->length());
+   for (int i = 0; i < fixed->length();  i++) {
+     Handle<Object> val = Handle<Object>(fixed->get(i));
+     param_data[i] = val.location();
+   }
+
+   Handle<Object> result = Execution::New(
+       function, fixed->length(), param_data, &exception);
+   return *result;
+
+}
+
 
 static Code* ComputeConstructStub(Handle<JSFunction> function) {
   Handle<Object> prototype = Factory::null_value();

src/runtime.h

@@ -258,6 +258,7 @@ namespace internal {
   /* Statements */ \
   F(NewClosure, 2, 1) \
   F(NewObject, 1, 1) \
+  F(NewObjectFromBound, 2, 1) \
   F(Throw, 1, 1) \
   F(ReThrow, 1, 1) \
   F(ThrowReferenceError, 1, 1) \

src/v8natives.js

@@ -1099,6 +1099,57 @@ function FunctionToString() {
 }
 
 
+// ES5 15.3.4.5
+function FunctionBind(this_arg) { // Length is 1.
+  if (!IS_FUNCTION(this)) {
+      throw new $TypeError('Bind must be called on a function');
+  }
+  // this_arg is not an argument that should be bound.
+  var argc_bound = %_ArgumentsLength() - 1;
+  if (argc_bound > 0) {
+    var bound_args = new $Array(argc_bound);
+    for(var i = 0; i < argc_bound; i++) {
+      bound_args[i] = %_Arguments(i+1);
+    }  
+  }
+  global.print(argc_bound);
+  var fn = this;
+  var result = function() {
+    // Combine the args we got from the bind call with the args
+    // given as argument to the invocation. 
+    var argc = %_ArgumentsLength();
+    var args = new $Array(argc + argc_bound);
+    // Add bound arguments.
+    for (var i = 0; i < argc_bound; i++) {
+      args[i] = bound_args[i];
+    }
+    // Add arguments from call.
+    for (var i = 0; i < argc; i++) {
+      args[argc_bound + i] = %_Arguments(i); 
+    }
+    // If this is a construct call we use a special runtime method
+    // to generate the actual object using the bound function.
+    if (%_IsConstructCall()) {
+      return %NewObjectFromBound(fn, args);
+    }
+    return fn.apply(this_arg, args);
+  };
+
+  // We already have caller and arguments properties on functions,
+  // which are non-configurable. It therefore makes no sence to
+  // try to redefine these as defined by the spec. The spec says
+  // that bind should make these throw a TypeError if get or set
+  // is called and make them non-enumerable and non-configurable.
+  // To be consistent with our normal functions we leave this as it is. 
+
+  // Set the correct length.
+  var length = (this.length - argc_bound) > 0 ? this.length - argc_bound : 0;
+  %FunctionSetLength(result, length);
+
+  return result;
+}
+
+
 function NewFunction(arg1) {  // length == 1
   var n = %_ArgumentsLength();
   var p = '';
@@ -1130,6 +1181,7 @@ function NewFunction(arg1) {  // length == 1
 
 function SetupFunction() {
   InstallFunctions($Function.prototype, DONT_ENUM, $Array(
+    "bind", FunctionBind,
     "toString", FunctionToString
   ));
 }

test/mjsunit/function-bind.js

@@ -0,0 +1,184 @@
+// Copyright 2010 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Tests the Function.prototype.bind (ES 15.3.4.5) method.
+
+// Simple tests.
+function foo(x, y, z) {
+  return x + y + z;
+}
+
+var f = foo.bind(foo);
+assertEquals(3, f(1, 1, 1));
+assertEquals(3, f.length);
+
+f = foo.bind(foo, 2);
+assertEquals(4, f(1, 1));
+assertEquals(2, f.length);
+
+f = foo.bind(foo, 2, 2);
+assertEquals(5, f(1));
+assertEquals(1, f.length);
+
+f = foo.bind(foo, 2, 2, 2);
+assertEquals(6, f());
+assertEquals(0, f.length);
+
+// Test that length works correctly even if more than the actual number
+// of arguments are given when binding.
+f = foo.bind(foo, 1, 2, 3, 4, 5, 6, 7, 8, 9);
+assertEquals(6, f());
+assertEquals(0, f.length);
+
+// Use a different bound object.
+var obj = {x: 42, y: 43};
+// Values that would normally be in "this" when calling f_bound_this.
+var x = 42;
+var y = 44;
+
+function f_bound_this(z) {
+  return z + this.y - this.x;
+} 
+
+assertEquals(3, f_bound_this(1))
+f = f_bound_this.bind(obj);
+assertEquals(2, f(1));
+assertEquals(1, f.length);
+
+f = f_bound_this.bind(obj, 2);
+assertEquals(3, f());
+assertEquals(0, f.length);
+
+// Test chained binds.
+
+// When only giving the thisArg, any number of binds should have 
+// the same effect.
+f = foo.bind(foo);
+assertEquals(3, f(1, 1, 1));
+f = foo.bind(foo).bind(foo).bind(foo).bind(foo);
+assertEquals(3, f(1, 1, 1));
+assertEquals(3, f.length);
+
+// Giving bound parameters should work at any place in the chain.
+f = foo.bind(foo, 1).bind(foo).bind(foo).bind(foo);
+assertEquals(3, f(1, 1));
+assertEquals(2, f.length);
+
+f = foo.bind(foo).bind(foo, 1).bind(foo).bind(foo);
+assertEquals(3, f(1, 1));
+assertEquals(2, f.length);
+
+f = foo.bind(foo).bind(foo).bind(foo,1 ).bind(foo);
+assertEquals(3, f(1, 1));
+assertEquals(2, f.length);
+
+f = foo.bind(foo).bind(foo).bind(foo).bind(foo, 1);
+assertEquals(3, f(1, 1));
+assertEquals(2, f.length);
+
+// Several parameters can be given, and given in different bind invokations.
+f = foo.bind(foo, 1, 1).bind(foo).bind(foo).bind(foo);
+assertEquals(3, f(1));
+assertEquals(1, f.length);
+
+f = foo.bind(foo).bind(foo, 1, 1).bind(foo).bind(foo);
+assertEquals(3, f(1));
+assertEquals(1, f.length);
+
+f = foo.bind(foo).bind(foo, 1, 1).bind(foo).bind(foo);
+assertEquals(3, f(1));
+assertEquals(1, f.length);
+
+f = foo.bind(foo).bind(foo).bind(foo, 1, 1).bind(foo);
+assertEquals(3, f(1));
+assertEquals(1, f.length);
+
+f = foo.bind(foo).bind(foo).bind(foo).bind(foo, 1, 1);
+assertEquals(3, f(1));
+assertEquals(1, f.length);
+
+f = foo.bind(foo, 1).bind(foo, 1).bind(foo).bind(foo);
+assertEquals(3, f(1));
+assertEquals(1, f.length);
+
+f = foo.bind(foo, 1).bind(foo).bind(foo, 1).bind(foo);
+assertEquals(3, f(1));
+assertEquals(1, f.length);
+
+f = foo.bind(foo, 1).bind(foo).bind(foo).bind(foo, 1);
+assertEquals(3, f(1));
+assertEquals(1, f.length);
+
+f = foo.bind(foo).bind(foo, 1).bind(foo).bind(foo, 1);
+assertEquals(3, f(1));
+assertEquals(1, f.length);
+
+// Test constructor calls.
+
+function bar(x, y, z) {
+  this.x = x;
+  this.y = y;
+  this.z = z;
+}
+
+f = bar.bind(bar);
+var obj2 = new f(1,2,3);
+assertEquals(1, obj2.x);
+assertEquals(2, obj2.y);
+assertEquals(3, obj2.z);
+
+f = bar.bind(bar, 1);
+obj2 = new f(2,3);
+assertEquals(1, obj2.x);
+assertEquals(2, obj2.y);
+assertEquals(3, obj2.z);
+
+f = bar.bind(bar, 1, 2);
+obj2 = new f(3);
+assertEquals(1, obj2.x);
+assertEquals(2, obj2.y);
+assertEquals(3, obj2.z);
+
+f = bar.bind(bar, 1, 2, 3);
+obj2 = new f();
+assertEquals(1, obj2.x);
+assertEquals(2, obj2.y);
+assertEquals(3, obj2.z);
+
+
+// Test bind chains when used as a constructor.
+
+f = bar.bind(bar, 1).bind(bar, 2).bind(bar, 3);
+obj2 = new f();
+assertEquals(1, obj2.x);
+assertEquals(2, obj2.y);
+assertEquals(3, obj2.z);
+
+// Test instanceof obj2 is bar, not f.
+assertTrue(obj2 instanceof bar);
+assertFalse(obj2 instanceof f);
+