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      1 // Copyright 2013 the V8 project authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 (function(global, utils) {
      6 
      7 "use strict";
      8 
      9 %CheckIsBootstrapping();
     10 
     11 // -------------------------------------------------------------------
     12 // Imports
     13 
     14 var GlobalObject = global.Object;
     15 var GlobalSymbol = global.Symbol;
     16 var hasInstanceSymbol = utils.ImportNow("has_instance_symbol");
     17 var isConcatSpreadableSymbol =
     18     utils.ImportNow("is_concat_spreadable_symbol");
     19 var iteratorSymbol = utils.ImportNow("iterator_symbol");
     20 var MakeTypeError;
     21 var toPrimitiveSymbol = utils.ImportNow("to_primitive_symbol");
     22 var toStringTagSymbol = utils.ImportNow("to_string_tag_symbol");
     23 var unscopablesSymbol = utils.ImportNow("unscopables_symbol");
     24 
     25 utils.Import(function(from) {
     26   MakeTypeError = from.MakeTypeError;
     27 });
     28 
     29 // -------------------------------------------------------------------
     30 
     31 // 19.4.3.4 Symbol.prototype [ @@toPrimitive ] ( hint )
     32 function SymbolToPrimitive(hint) {
     33   if (!(IS_SYMBOL(this) || IS_SYMBOL_WRAPPER(this))) {
     34     throw MakeTypeError(kIncompatibleMethodReceiver,
     35                         "Symbol.prototype [ @@toPrimitive ]", this);
     36   }
     37   return %_ValueOf(this);
     38 }
     39 
     40 
     41 function SymbolToString() {
     42   if (!(IS_SYMBOL(this) || IS_SYMBOL_WRAPPER(this))) {
     43     throw MakeTypeError(kIncompatibleMethodReceiver,
     44                         "Symbol.prototype.toString", this);
     45   }
     46   return %SymbolDescriptiveString(%_ValueOf(this));
     47 }
     48 
     49 
     50 function SymbolValueOf() {
     51   if (!(IS_SYMBOL(this) || IS_SYMBOL_WRAPPER(this))) {
     52     throw MakeTypeError(kIncompatibleMethodReceiver,
     53                         "Symbol.prototype.valueOf", this);
     54   }
     55   return %_ValueOf(this);
     56 }
     57 
     58 
     59 function SymbolFor(key) {
     60   key = TO_STRING(key);
     61   var registry = %SymbolRegistry();
     62   if (IS_UNDEFINED(registry.for[key])) {
     63     var symbol = %CreateSymbol(key);
     64     registry.for[key] = symbol;
     65     registry.keyFor[symbol] = key;
     66   }
     67   return registry.for[key];
     68 }
     69 
     70 
     71 function SymbolKeyFor(symbol) {
     72   if (!IS_SYMBOL(symbol)) throw MakeTypeError(kSymbolKeyFor, symbol);
     73   return %SymbolRegistry().keyFor[symbol];
     74 }
     75 
     76 
     77 // ES6 19.1.2.8
     78 function ObjectGetOwnPropertySymbols(obj) {
     79   obj = TO_OBJECT(obj);
     80 
     81   return %GetOwnPropertyKeys(obj, PROPERTY_FILTER_SKIP_STRINGS);
     82 }
     83 
     84 // -------------------------------------------------------------------
     85 
     86 %FunctionSetPrototype(GlobalSymbol, new GlobalObject());
     87 
     88 utils.InstallConstants(GlobalSymbol, [
     89   // TODO(rossberg): expose when implemented.
     90   // "hasInstance", hasInstanceSymbol,
     91   // "isConcatSpreadable", isConcatSpreadableSymbol,
     92   "iterator", iteratorSymbol,
     93   // TODO(yangguo): expose when implemented.
     94   // "match", matchSymbol,
     95   // "replace", replaceSymbol,
     96   // "search", searchSymbol,
     97   // "split, splitSymbol,
     98   "toPrimitive", toPrimitiveSymbol,
     99   // TODO(dslomov, caitp): Currently defined in harmony-tostring.js ---
    100   // Move here when shipping
    101   // "toStringTag", toStringTagSymbol,
    102   "unscopables", unscopablesSymbol,
    103 ]);
    104 
    105 utils.InstallFunctions(GlobalSymbol, DONT_ENUM, [
    106   "for", SymbolFor,
    107   "keyFor", SymbolKeyFor
    108 ]);
    109 
    110 %AddNamedProperty(
    111     GlobalSymbol.prototype, "constructor", GlobalSymbol, DONT_ENUM);
    112 %AddNamedProperty(
    113     GlobalSymbol.prototype, toStringTagSymbol, "Symbol", DONT_ENUM | READ_ONLY);
    114 
    115 utils.InstallFunctions(GlobalSymbol.prototype, DONT_ENUM | READ_ONLY, [
    116   toPrimitiveSymbol, SymbolToPrimitive
    117 ]);
    118 
    119 utils.InstallFunctions(GlobalSymbol.prototype, DONT_ENUM, [
    120   "toString", SymbolToString,
    121   "valueOf", SymbolValueOf
    122 ]);
    123 
    124 utils.InstallFunctions(GlobalObject, DONT_ENUM, [
    125   "getOwnPropertySymbols", ObjectGetOwnPropertySymbols
    126 ]);
    127 
    128 // -------------------------------------------------------------------
    129 // Exports
    130 
    131 utils.Export(function(to) {
    132   to.SymbolToString = SymbolToString;
    133 })
    134 
    135 })
    136