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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
// ES7 draft (January 21, 2016) 19.2.3.2 Function.prototype.bind
function FunctionBind(thisArg, ...boundArgs) {
// Step 1.
var target = this;
// Step 2.
if (!IsCallable(target))
ThrowTypeError(JSMSG_INCOMPATIBLE_PROTO, "Function", "bind", target);
// Step 3 (implicit).
// Step 4.
var F;
var argCount = boundArgs.length;
switch (argCount) {
case 0:
F = bind_bindFunction0(target, thisArg, boundArgs);
break;
case 1:
F = bind_bindFunction1(target, thisArg, boundArgs);
break;
case 2:
F = bind_bindFunction2(target, thisArg, boundArgs);
break;
default:
F = bind_bindFunctionN(target, thisArg, boundArgs);
}
// Steps 5-11.
_FinishBoundFunctionInit(F, target, argCount);
// Ensure that the apply intrinsic has been cloned so it can be baked into
// JIT code.
void std_Function_apply;
// Step 12.
return F;
}
/**
* bind_bindFunction{0,1,2} are special cases of the generic bind_bindFunctionN
* below. They avoid the need to merge the lists of bound arguments and call
* arguments to the bound function into a new list which is then used in a
* destructuring call of the bound function.
*
* All three of these functions again have special-cases for call argument
* counts between 0 and 5. For calls with 6+ arguments, all - bound and call -
* arguments are copied into an array before invoking the generic call and
* construct helper functions. This avoids having to use rest parameters and
* destructuring in the fast path.
*
* Directly embedding the for-loop to combine bound and call arguments may
* inhibit inlining of the bound function, so we use a separate combiner
* function to perform this task. This combiner function is created lazily to
* ensure we only pay its construction cost when needed.
*
* All bind_bindFunction{X} functions have the same signature to enable simple
* reading out of closed-over state by debugging functions.
*/
function bind_bindFunction0(fun, thisArg, boundArgs) {
return function bound() {
// Ensure we allocate a call-object slot for |boundArgs|, so the
// debugger can access this value.
if (false) void boundArgs;
var newTarget;
if (_IsConstructing()) {
newTarget = new.target;
if (newTarget === bound)
newTarget = fun;
switch (arguments.length) {
case 0:
return constructContentFunction(fun, newTarget);
case 1:
return constructContentFunction(fun, newTarget, SPREAD(arguments, 1));
case 2:
return constructContentFunction(fun, newTarget, SPREAD(arguments, 2));
case 3:
return constructContentFunction(fun, newTarget, SPREAD(arguments, 3));
case 4:
return constructContentFunction(fun, newTarget, SPREAD(arguments, 4));
case 5:
return constructContentFunction(fun, newTarget, SPREAD(arguments, 5));
default:
var args = FUN_APPLY(bind_mapArguments, null, arguments);
return bind_constructFunctionN(fun, newTarget, args);
}
} else {
switch (arguments.length) {
case 0:
return callContentFunction(fun, thisArg);
case 1:
return callContentFunction(fun, thisArg, SPREAD(arguments, 1));
case 2:
return callContentFunction(fun, thisArg, SPREAD(arguments, 2));
case 3:
return callContentFunction(fun, thisArg, SPREAD(arguments, 3));
case 4:
return callContentFunction(fun, thisArg, SPREAD(arguments, 4));
case 5:
return callContentFunction(fun, thisArg, SPREAD(arguments, 5));
default:
return FUN_APPLY(fun, thisArg, arguments);
}
}
};
}
function bind_bindFunction1(fun, thisArg, boundArgs) {
var bound1 = boundArgs[0];
var combiner = null;
return function bound() {
// Ensure we allocate a call-object slot for |boundArgs|, so the
// debugger can access this value.
if (false) void boundArgs;
var newTarget;
if (_IsConstructing()) {
newTarget = new.target;
if (newTarget === bound)
newTarget = fun;
switch (arguments.length) {
case 0:
return constructContentFunction(fun, newTarget, bound1);
case 1:
return constructContentFunction(fun, newTarget, bound1, SPREAD(arguments, 1));
case 2:
return constructContentFunction(fun, newTarget, bound1, SPREAD(arguments, 2));
case 3:
return constructContentFunction(fun, newTarget, bound1, SPREAD(arguments, 3));
case 4:
return constructContentFunction(fun, newTarget, bound1, SPREAD(arguments, 4));
case 5:
return constructContentFunction(fun, newTarget, bound1, SPREAD(arguments, 5));
}
} else {
switch (arguments.length) {
case 0:
return callContentFunction(fun, thisArg, bound1);
case 1:
return callContentFunction(fun, thisArg, bound1, SPREAD(arguments, 1));
case 2:
return callContentFunction(fun, thisArg, bound1, SPREAD(arguments, 2));
case 3:
return callContentFunction(fun, thisArg, bound1, SPREAD(arguments, 3));
case 4:
return callContentFunction(fun, thisArg, bound1, SPREAD(arguments, 4));
case 5:
return callContentFunction(fun, thisArg, bound1, SPREAD(arguments, 5));
}
}
if (combiner === null) {
combiner = function() {
var callArgsCount = arguments.length;
var args = std_Array(1 + callArgsCount);
_DefineDataProperty(args, 0, bound1);
for (var i = 0; i < callArgsCount; i++)
_DefineDataProperty(args, i + 1, arguments[i]);
return args;
};
}
var args = FUN_APPLY(combiner, null, arguments);
if (newTarget === undefined)
return bind_applyFunctionN(fun, thisArg, args);
return bind_constructFunctionN(fun, newTarget, args);
};
}
function bind_bindFunction2(fun, thisArg, boundArgs) {
var bound1 = boundArgs[0];
var bound2 = boundArgs[1];
var combiner = null;
return function bound() {
// Ensure we allocate a call-object slot for |boundArgs|, so the
// debugger can access this value.
if (false) void boundArgs;
var newTarget;
if (_IsConstructing()) {
newTarget = new.target;
if (newTarget === bound)
newTarget = fun;
switch (arguments.length) {
case 0:
return constructContentFunction(fun, newTarget, bound1, bound2);
case 1:
return constructContentFunction(fun, newTarget, bound1, bound2, SPREAD(arguments, 1));
case 2:
return constructContentFunction(fun, newTarget, bound1, bound2, SPREAD(arguments, 2));
case 3:
return constructContentFunction(fun, newTarget, bound1, bound2, SPREAD(arguments, 3));
case 4:
return constructContentFunction(fun, newTarget, bound1, bound2, SPREAD(arguments, 4));
case 5:
return constructContentFunction(fun, newTarget, bound1, bound2, SPREAD(arguments, 5));
}
} else {
switch (arguments.length) {
case 0:
return callContentFunction(fun, thisArg, bound1, bound2);
case 1:
return callContentFunction(fun, thisArg, bound1, bound2, SPREAD(arguments, 1));
case 2:
return callContentFunction(fun, thisArg, bound1, bound2, SPREAD(arguments, 2));
case 3:
return callContentFunction(fun, thisArg, bound1, bound2, SPREAD(arguments, 3));
case 4:
return callContentFunction(fun, thisArg, bound1, bound2, SPREAD(arguments, 4));
case 5:
return callContentFunction(fun, thisArg, bound1, bound2, SPREAD(arguments, 5));
}
}
if (combiner === null) {
combiner = function() {
var callArgsCount = arguments.length;
var args = std_Array(2 + callArgsCount);
_DefineDataProperty(args, 0, bound1);
_DefineDataProperty(args, 1, bound2);
for (var i = 0; i < callArgsCount; i++)
_DefineDataProperty(args, i + 2, arguments[i]);
return args;
};
}
var args = FUN_APPLY(combiner, null, arguments);
if (newTarget === undefined)
return bind_applyFunctionN(fun, thisArg, args);
return bind_constructFunctionN(fun, newTarget, args);
};
}
function bind_bindFunctionN(fun, thisArg, boundArgs) {
assert(boundArgs.length > 2, "Fast paths should be used for few-bound-args cases.");
var combiner = null;
return function bound() {
var newTarget;
if (_IsConstructing()) {
newTarget = new.target;
if (newTarget === bound)
newTarget = fun;
}
if (arguments.length === 0) {
if (newTarget !== undefined)
return bind_constructFunctionN(fun, newTarget, boundArgs);
return bind_applyFunctionN(fun, thisArg, boundArgs);
}
if (combiner === null) {
combiner = function() {
var boundArgsCount = boundArgs.length;
var callArgsCount = arguments.length;
var args = std_Array(boundArgsCount + callArgsCount);
for (var i = 0; i < boundArgsCount; i++)
_DefineDataProperty(args, i, boundArgs[i]);
for (var i = 0; i < callArgsCount; i++)
_DefineDataProperty(args, i + boundArgsCount, arguments[i]);
return args;
};
}
var args = FUN_APPLY(combiner, null, arguments);
if (newTarget !== undefined)
return bind_constructFunctionN(fun, newTarget, args);
return bind_applyFunctionN(fun, thisArg, args);
};
}
function bind_mapArguments() {
var len = arguments.length;
var args = std_Array(len);
for (var i = 0; i < len; i++)
_DefineDataProperty(args, i, arguments[i]);
return args;
}
function bind_applyFunctionN(fun, thisArg, args) {
switch (args.length) {
case 0:
return callContentFunction(fun, thisArg);
case 1:
return callContentFunction(fun, thisArg, SPREAD(args, 1));
case 2:
return callContentFunction(fun, thisArg, SPREAD(args, 2));
case 3:
return callContentFunction(fun, thisArg, SPREAD(args, 3));
case 4:
return callContentFunction(fun, thisArg, SPREAD(args, 4));
case 5:
return callContentFunction(fun, thisArg, SPREAD(args, 5));
case 6:
return callContentFunction(fun, thisArg, SPREAD(args, 6));
case 7:
return callContentFunction(fun, thisArg, SPREAD(args, 7));
case 8:
return callContentFunction(fun, thisArg, SPREAD(args, 8));
case 9:
return callContentFunction(fun, thisArg, SPREAD(args, 9));
default:
return FUN_APPLY(fun, thisArg, args);
}
}
function bind_constructFunctionN(fun, newTarget, args) {
switch (args.length) {
case 1:
return constructContentFunction(fun, newTarget, SPREAD(args, 1));
case 2:
return constructContentFunction(fun, newTarget, SPREAD(args, 2));
case 3:
return constructContentFunction(fun, newTarget, SPREAD(args, 3));
case 4:
return constructContentFunction(fun, newTarget, SPREAD(args, 4));
case 5:
return constructContentFunction(fun, newTarget, SPREAD(args, 5));
case 6:
return constructContentFunction(fun, newTarget, SPREAD(args, 6));
case 7:
return constructContentFunction(fun, newTarget, SPREAD(args, 7));
case 8:
return constructContentFunction(fun, newTarget, SPREAD(args, 8));
case 9:
return constructContentFunction(fun, newTarget, SPREAD(args, 9));
case 10:
return constructContentFunction(fun, newTarget, SPREAD(args, 10));
case 11:
return constructContentFunction(fun, newTarget, SPREAD(args, 11));
case 12:
return constructContentFunction(fun, newTarget, SPREAD(args, 12));
default:
assert(args.length !== 0,
"bound function construction without args should be handled by caller");
return _ConstructFunction(fun, newTarget, args);
}
}
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