js/src/vm/Iterator.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim:set ts=2 sw=2 sts=2 et cindent: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "js/Iterator.h"
   8
   9 #include "js/Conversions.h"
  10 #include "vm/Interpreter.h"
  11 #include "vm/JSAtomState.h"
  12 #include "vm/JSContext.h"
  13 #include "vm/ObjectOperations.h"
  14 #include "vm/SelfHosting.h"
  15 #include "vm/StringType.h"
  16 #include "vm/JSObject-inl.h"
  17
  18 using namespace js;
  19
  20 namespace JS {
  21
  22 // https://tc39.es/ecma262/#sec-getiterator
  23 // GetIterator(obj [, hint [, method]])
  24 JSObject* GetIteratorObject(JSContext* cx, HandleValue obj, bool isAsync) {
  25   FixedInvokeArgs<3> args(cx);
  26   args[0].set(obj);
  27   args[1].setBoolean(isAsync);
  28   args[2].setUndefined();  // method
  29
  30   RootedValue rval(cx);
  31   if (!CallSelfHostedFunction(cx, cx->names().GetIterator, UndefinedHandleValue,
  32                               args, &rval)) {
  33     return nullptr;
  34   }
  35
  36   MOZ_ASSERT(rval.isObject());
  37   return &rval.toObject();
  38 }
  39
  40 // https://tc39.es/ecma262/#sec-iteratornext
  41 bool IteratorNext(JSContext* cx, HandleObject iteratorRecord,
  42                   MutableHandleValue result) {
  43   FixedInvokeArgs<1> args(cx);
  44   args[0].setObject(*iteratorRecord);
  45   return CallSelfHostedFunction(cx, cx->names().IteratorNext,
  46                                 UndefinedHandleValue, args, result);
  47 }
  48
  49 // https://tc39.es/ecma262/#sec-iteratorcomplete
  50 bool IteratorComplete(JSContext* cx, HandleObject iterResult, bool* done) {
  51   RootedValue doneV(cx);
  52   if (!GetProperty(cx, iterResult, iterResult, cx->names().done, &doneV)) {
  53     return false;
  54   }
  55
  56   *done = ToBoolean(doneV);
  57   return true;
  58 }
  59
  60 // https://tc39.es/ecma262/#sec-iteratorvalue
  61 bool IteratorValue(JSContext* cx, HandleObject iterResult,
  62                    MutableHandleValue value) {
  63   return GetProperty(cx, iterResult, iterResult, cx->names().value, value);
  64 }
  65
  66 bool GetIteratorRecordIterator(JSContext* cx, HandleObject iteratorRecord,
  67                                MutableHandleValue iterator) {
  68   return GetProperty(cx, iteratorRecord, iteratorRecord, cx->names().iterator,
  69                      iterator);
  70 }
  71
  72 static bool GetMethod(JSContext* cx, HandleValue v, Handle<PropertyName*> name,
  73                       MutableHandleValue result) {
  74   // Step 1. Let func be ? GetV(V, P).
  75   RootedValue func(cx);
  76   if (!GetProperty(cx, v, name, &func)) {
  77     return false;
  78   }
  79
  80   // Step 2. If func is either undefined or null, return undefined.
  81   if (func.isNullOrUndefined()) {
  82     result.setUndefined();
  83     return true;
  84   }
  85
  86   // Step 3. If IsCallable(func) is false, throw a TypeError exception.
  87   if (!IsCallable(func)) {
  88     return ReportIsNotFunction(cx, func, -1);
  89   }
  90
  91   // Step 4. Return func.
  92   result.set(func);
  93   return true;
  94 }
  95
  96 bool GetReturnMethod(JSContext* cx, HandleValue iterator,
  97                      MutableHandleValue result) {
  98   // Step 2. Let returnMethod be GetMethod(iterator, "return").
  99   return GetMethod(cx, iterator, cx->names().return_, result);
 100 }
 101
 102 }  // namespace JS