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-rw-r--r--js/src/builtin/Iterator.js681
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diff --git a/js/src/builtin/Iterator.js b/js/src/builtin/Iterator.js
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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/. */
+
+function IteratorIdentity() {
+ return this;
+}
+
+/* ECMA262 7.2.7 */
+function IteratorNext(iteratorRecord, value) {
+ // Steps 1-2.
+ const result = (arguments.length < 2
+ ? callContentFunction(iteratorRecord.nextMethod, iteratorRecord.iterator)
+ : callContentFunction(iteratorRecord.nextMethod, iteratorRecord.iterator, value));
+ // Step 3.
+ if (!IsObject(result)) {
+ ThrowTypeError(JSMSG_OBJECT_REQUIRED, result);
+ }
+ // Step 4.
+ return result;
+}
+
+/* ECMA262 7.4.6 */
+function IteratorClose(iteratorRecord, value) {
+ // Step 3.
+ const iterator = iteratorRecord.iterator;
+ // Step 4.
+ const returnMethod = iterator.return;
+ // Step 5.
+ if (returnMethod !== undefined && returnMethod !== null) {
+ const result = callContentFunction(returnMethod, iterator);
+ // Step 8.
+ if (!IsObject(result)) {
+ ThrowTypeError(JSMSG_OBJECT_REQUIRED, DecompileArg(0, result));
+ }
+ }
+ // Step 5b & 9.
+ return value;
+}
+
+/* Iterator Helpers proposal 1.1.1 */
+function GetIteratorDirect(obj) {
+ // Step 1.
+ if (!IsObject(obj)) {
+ ThrowTypeError(JSMSG_OBJECT_REQUIRED, DecompileArg(0, obj));
+ }
+
+ // Step 2.
+ const nextMethod = obj.next;
+ // Step 3.
+ if (!IsCallable(nextMethod)) {
+ ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, nextMethod));
+ }
+
+ // Steps 4-5.
+ return {
+ iterator: obj,
+ nextMethod,
+ done: false,
+ };
+}
+
+function GetIteratorDirectWrapper(obj) {
+ // Step 1.
+ if (!IsObject(obj)) {
+ ThrowTypeError(JSMSG_OBJECT_REQUIRED, obj);
+ }
+
+ // Step 2.
+ const nextMethod = obj.next;
+ // Step 3.
+ if (!IsCallable(nextMethod)) {
+ ThrowTypeError(JSMSG_NOT_FUNCTION, nextMethod);
+ }
+
+ // Steps 4-5.
+ return {
+ // Use a named function expression instead of a method definition, so
+ // we don't create an inferred name for this function at runtime.
+ [std_iterator]: function IteratorMethod() {
+ return this;
+ },
+ next(value) {
+ return callContentFunction(nextMethod, obj, value);
+ },
+ return(value) {
+ const returnMethod = obj.return;
+ if (returnMethod !== undefined && returnMethod !== null) {
+ return callContentFunction(returnMethod, obj, value);
+ }
+ return {done: true, value};
+ },
+ };
+}
+
+/* Iterator Helpers proposal 1.1.2 */
+function IteratorStep(iteratorRecord, value) {
+ // Steps 2-3.
+ let result;
+ if (arguments.length === 2) {
+ result = callContentFunction(
+ iteratorRecord.nextMethod,
+ iteratorRecord.iterator,
+ value
+ );
+ } else {
+ result = callContentFunction(
+ iteratorRecord.nextMethod,
+ iteratorRecord.iterator
+ );
+ }
+
+ // IteratorNext Step 3.
+ if (!IsObject(result)) {
+ ThrowTypeError(JSMSG_OBJECT_REQUIRED, DecompileArg(0, result));
+ }
+
+ // Steps 4-6.
+ return result.done ? false : result;
+}
+
+/* Iterator Helpers proposal 2.1.3.3.1 */
+function IteratorFrom(O) {
+ // Step 1.
+ const usingIterator = O[std_iterator];
+
+ let iteratorRecord;
+ // Step 2.
+ if (usingIterator !== undefined && usingIterator !== null) {
+ // Step a.
+ // Inline call to GetIterator.
+ const iterator = callContentFunction(usingIterator, O);
+ iteratorRecord = GetIteratorDirect(iterator);
+ // Step b-c.
+ if (iteratorRecord.iterator instanceof GetBuiltinConstructor("Iterator")) {
+ return iteratorRecord.iterator;
+ }
+ } else {
+ // Step 3.
+ iteratorRecord = GetIteratorDirect(O);
+ }
+
+ // Step 4.
+ const wrapper = NewWrapForValidIterator();
+ // Step 5.
+ UnsafeSetReservedSlot(wrapper, ITERATED_SLOT, iteratorRecord);
+ // Step 6.
+ return wrapper;
+}
+
+/* Iterator Helpers proposal 2.1.3.3.1.1.1 */
+function WrapForValidIteratorNext(value) {
+ // Step 1-2.
+ let O;
+ if (!IsObject(this) || (O = GuardToWrapForValidIterator(this)) === null) {
+ if (arguments.length === 0) {
+ return callFunction(CallWrapForValidIteratorMethodIfWrapped, this,
+ "WrapForValidIteratorNext");
+ }
+ return callFunction(CallWrapForValidIteratorMethodIfWrapped, this,
+ value, "WrapForValidIteratorNext");
+ }
+ const iterated = UnsafeGetReservedSlot(O, ITERATED_SLOT);
+ // Step 3.
+ let result;
+ if (arguments.length === 0) {
+ result = callContentFunction(iterated.nextMethod, iterated.iterator);
+ } else { // Step 4.
+ result = callContentFunction(iterated.nextMethod, iterated.iterator, value);
+ }
+ // Inlined from IteratorNext.
+ if (!IsObject(result))
+ ThrowTypeError(JSMSG_OBJECT_REQUIRED, DecompileArg(0, result));
+ return result;
+}
+
+/* Iterator Helpers proposal 2.1.3.3.1.1.2 */
+function WrapForValidIteratorReturn(value) {
+ // Step 1-2.
+ let O;
+ if (!IsObject(this) || (O = GuardToWrapForValidIterator(this)) === null) {
+ return callFunction(CallWrapForValidIteratorMethodIfWrapped, this,
+ value, "WrapForValidIteratorReturn");
+ }
+ const iterated = UnsafeGetReservedSlot(O, ITERATED_SLOT);
+
+ // Step 3.
+ // Inline call to IteratorClose.
+ const iterator = iterated.iterator;
+ const returnMethod = iterator.return;
+ if (returnMethod !== undefined && returnMethod !== null) {
+ let innerResult = callContentFunction(returnMethod, iterator);
+ if (!IsObject(innerResult)) {
+ ThrowTypeError(JSMSG_OBJECT_REQUIRED, DecompileArg(0, innerResult));
+ }
+ }
+ // Step 4.
+ return {
+ done: true,
+ value,
+ };
+}
+
+/* Iterator Helpers proposal 2.1.3.3.1.1.3 */
+function WrapForValidIteratorThrow(value) {
+ // Step 1-2.
+ let O;
+ if (!IsObject(this) || (O = GuardToWrapForValidIterator(this)) === null) {
+ return callFunction(CallWrapForValidIteratorMethodIfWrapped, this,
+ value, "WrapForValidIteratorThrow");
+ }
+ const iterated = UnsafeGetReservedSlot(O, ITERATED_SLOT);
+ // Step 3.
+ const iterator = iterated.iterator;
+ // Step 4.
+ const throwMethod = iterator.throw;
+ // Step 5.
+ if (throwMethod === undefined || throwMethod === null) {
+ throw value;
+ }
+ // Step 6.
+ return callContentFunction(throwMethod, iterator, value);
+}
+
+/* Iterator Helper object prototype methods. */
+function IteratorHelperNext(value) {
+ let O;
+ if (!IsObject(this) || (O = GuardToIteratorHelper(this)) === null) {
+ return callFunction(CallIteratorHelperMethodIfWrapped, this,
+ value, "IteratorHelperNext");
+ }
+ const generator = UnsafeGetReservedSlot(O, ITERATOR_HELPER_GENERATOR_SLOT);
+ return callContentFunction(GeneratorNext, generator, value);
+}
+
+function IteratorHelperReturn(value) {
+ let O;
+ if (!IsObject(this) || (O = GuardToIteratorHelper(this)) === null) {
+ return callFunction(CallIteratorHelperMethodIfWrapped, this,
+ value, "IteratorHelperReturn");
+ }
+ const generator = UnsafeGetReservedSlot(O, ITERATOR_HELPER_GENERATOR_SLOT);
+ return callContentFunction(GeneratorReturn, generator, value);
+}
+
+function IteratorHelperThrow(value) {
+ let O;
+ if (!IsObject(this) || (O = GuardToIteratorHelper(this)) === null) {
+ return callFunction(CallIteratorHelperMethodIfWrapped, this,
+ value, "IteratorHelperThrow");
+ }
+ const generator = UnsafeGetReservedSlot(O, ITERATOR_HELPER_GENERATOR_SLOT);
+ return callContentFunction(GeneratorThrow, generator, value);
+}
+
+// Lazy %Iterator.prototype% methods
+// Iterator Helpers proposal 2.1.5.2-2.1.5.7
+//
+// In order to match the semantics of the built-in generator objects used in
+// the proposal, we use a reserved slot on the IteratorHelper objects to store
+// a regular generator that is called from the %IteratorHelper.prototype%
+// methods.
+//
+// Each of the lazy methods is divided into a prelude and a body, with the
+// eager prelude steps being contained in the corresponding IteratorX method
+// and the lazy body steps inside the IteratorXGenerator generator functions.
+//
+// Each prelude method initializes and returns a new IteratorHelper object.
+// As part of this initialization process, the appropriate generator function
+// is called, followed by GeneratorNext being called on returned generator
+// instance in order to move it to it's first yield point. This is done so that
+// if the return or throw methods are called on the IteratorHelper before next
+// has been called, we can catch them in the try and use the finally block to
+// close the source iterator.
+//
+// The needClose flag is used to track when the source iterator should be closed
+// following an exception being thrown within the generator, corresponding to
+// whether or not the abrupt completions in the spec are being passed back to
+// the caller (when needClose is false) or handled with IfAbruptCloseIterator
+// (when needClose is true).
+
+/* Iterator Helpers proposal 2.1.5.2 Prelude */
+function IteratorMap(mapper) {
+ // Step 1.
+ const iterated = GetIteratorDirect(this);
+
+ // Step 2.
+ if (!IsCallable(mapper)) {
+ ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, mapper));
+ }
+
+ const iteratorHelper = NewIteratorHelper();
+ const generator = IteratorMapGenerator(iterated, mapper);
+ callContentFunction(GeneratorNext, generator);
+ UnsafeSetReservedSlot(iteratorHelper, ITERATOR_HELPER_GENERATOR_SLOT, generator);
+ return iteratorHelper;
+}
+
+/* Iterator Helpers proposal 2.1.5.2 Body */
+function* IteratorMapGenerator(iterated, mapper) {
+ // Step 1.
+ let lastValue;
+ // Step 2.
+ let needClose = true;
+ try {
+ yield;
+ needClose = false;
+
+ for (let next = IteratorStep(iterated, lastValue);
+ next;
+ next = IteratorStep(iterated, lastValue)) {
+ // Step c.
+ const value = next.value;
+
+ // Steps d-g.
+ needClose = true;
+ lastValue = yield callContentFunction(mapper, undefined, value);
+ needClose = false;
+ }
+ } finally {
+ if (needClose) {
+ IteratorClose(iterated);
+ }
+ }
+}
+
+/* Iterator Helpers proposal 2.1.5.3 Prelude */
+function IteratorFilter(filterer) {
+ // Step 1.
+ const iterated = GetIteratorDirect(this);
+
+ // Step 2.
+ if (!IsCallable(filterer)) {
+ ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, filterer));
+ }
+
+ const iteratorHelper = NewIteratorHelper();
+ const generator = IteratorFilterGenerator(iterated, filterer);
+ callContentFunction(GeneratorNext, generator);
+ UnsafeSetReservedSlot(iteratorHelper, ITERATOR_HELPER_GENERATOR_SLOT, generator);
+ return iteratorHelper;
+}
+
+/* Iterator Helpers proposal 2.1.5.3 Body */
+function* IteratorFilterGenerator(iterated, filterer) {
+ // Step 1.
+ let lastValue;
+ // Step 2.
+ let needClose = true;
+ try {
+ yield;
+ needClose = false;
+
+ for (let next = IteratorStep(iterated, lastValue);
+ next;
+ next = IteratorStep(iterated, lastValue)) {
+ // Step c.
+ const value = next.value;
+
+ // Steps d-g.
+ needClose = true;
+ if (callContentFunction(filterer, undefined, value)) {
+ lastValue = yield value;
+ }
+ needClose = false;
+ }
+ } finally {
+ if (needClose) {
+ IteratorClose(iterated);
+ }
+ }
+}
+
+/* Iterator Helpers proposal 2.1.5.4 Prelude */
+function IteratorTake(limit) {
+ // Step 1.
+ const iterated = GetIteratorDirect(this);
+
+ // Step 2.
+ const remaining = ToInteger(limit);
+ // Step 3.
+ if (remaining < 0) {
+ ThrowRangeError(JSMSG_NEGATIVE_LIMIT);
+ }
+
+ const iteratorHelper = NewIteratorHelper();
+ const generator = IteratorTakeGenerator(iterated, remaining);
+ callContentFunction(GeneratorNext, generator);
+ UnsafeSetReservedSlot(iteratorHelper, ITERATOR_HELPER_GENERATOR_SLOT, generator);
+ return iteratorHelper;
+}
+
+/* Iterator Helpers proposal 2.1.5.4 Body */
+function* IteratorTakeGenerator(iterated, remaining) {
+ // Step 1.
+ let lastValue;
+ // Step 2.
+ let needClose = true;
+ try {
+ yield;
+ needClose = false;
+
+ for (; remaining > 0; remaining--) {
+ const next = IteratorStep(iterated, lastValue);
+ if (!next) {
+ return;
+ }
+
+ const value = next.value;
+ needClose = true;
+ lastValue = yield value;
+ needClose = false;
+ }
+ } finally {
+ if (needClose) {
+ IteratorClose(iterated);
+ }
+ }
+
+ IteratorClose(iterated);
+}
+
+/* Iterator Helpers proposal 2.1.5.5 Prelude */
+function IteratorDrop(limit) {
+ // Step 1.
+ const iterated = GetIteratorDirect(this);
+
+ // Step 2.
+ const remaining = ToInteger(limit);
+ // Step 3.
+ if (remaining < 0) {
+ ThrowRangeError(JSMSG_NEGATIVE_LIMIT);
+ }
+
+ const iteratorHelper = NewIteratorHelper();
+ const generator = IteratorDropGenerator(iterated, remaining);
+ callContentFunction(GeneratorNext, generator);
+ UnsafeSetReservedSlot(iteratorHelper, ITERATOR_HELPER_GENERATOR_SLOT, generator);
+ return iteratorHelper;
+}
+
+/* Iterator Helpers proposal 2.1.5.5 Body */
+function* IteratorDropGenerator(iterated, remaining) {
+ let needClose = true;
+ try {
+ yield;
+ needClose = false;
+
+ // Step 1.
+ for (; remaining > 0; remaining--) {
+ if (!IteratorStep(iterated)) {
+ return;
+ }
+ }
+
+ // Step 2.
+ let lastValue;
+ // Step 3.
+ for (let next = IteratorStep(iterated, lastValue);
+ next;
+ next = IteratorStep(iterated, lastValue)) {
+ // Steps c-d.
+ const value = next.value;
+
+ needClose = true;
+ lastValue = yield value;
+ needClose = false;
+ }
+ } finally {
+ if (needClose) {
+ IteratorClose(iterated);
+ }
+ }
+}
+
+/* Iterator Helpers proposal 2.1.5.6 Prelude */
+function IteratorAsIndexedPairs() {
+ // Step 1.
+ const iterated = GetIteratorDirect(this);
+
+ const iteratorHelper = NewIteratorHelper();
+ const generator = IteratorAsIndexedPairsGenerator(iterated);
+ callContentFunction(GeneratorNext, generator);
+ UnsafeSetReservedSlot(iteratorHelper, ITERATOR_HELPER_GENERATOR_SLOT, generator);
+ return iteratorHelper;
+}
+
+/* Iterator Helpers proposal 2.1.5.6 Body */
+function* IteratorAsIndexedPairsGenerator(iterated) {
+ // Step 2.
+ let lastValue;
+ // Step 3.
+ let needClose = true;
+ try {
+ yield;
+ needClose = false;
+
+ for (let next = IteratorStep(iterated, lastValue), index = 0;
+ next;
+ next = IteratorStep(iterated, lastValue), index++) {
+ // Steps c-d.
+ const value = next.value;
+
+ needClose = true;
+ lastValue = yield [index, value];
+ needClose = false;
+ }
+ } finally {
+ if (needClose) {
+ IteratorClose(iterated);
+ }
+ }
+}
+
+/* Iterator Helpers proposal 2.1.5.7 Prelude */
+function IteratorFlatMap(mapper) {
+ // Step 1.
+ const iterated = GetIteratorDirect(this);
+
+ // Step 2.
+ if (!IsCallable(mapper)) {
+ ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, mapper));
+ }
+
+ const iteratorHelper = NewIteratorHelper();
+ const generator = IteratorFlatMapGenerator(iterated, mapper);
+ callContentFunction(GeneratorNext, generator);
+ UnsafeSetReservedSlot(iteratorHelper, ITERATOR_HELPER_GENERATOR_SLOT, generator);
+ return iteratorHelper;
+}
+
+/* Iterator Helpers proposal 2.1.5.7 Body */
+function* IteratorFlatMapGenerator(iterated, mapper) {
+ // Step 1.
+ let needClose = true;
+ try {
+ yield;
+ needClose = false;
+
+ for (let next = IteratorStep(iterated);
+ next;
+ next = IteratorStep(iterated)) {
+ // Step c.
+ const value = next.value;
+
+ needClose = true;
+ // Step d.
+ const mapped = callContentFunction(mapper, undefined, value);
+ // Steps f-i.
+ for (const innerValue of allowContentIter(mapped)) {
+ yield innerValue;
+ }
+ needClose = false;
+ }
+ } finally {
+ if (needClose) {
+ IteratorClose(iterated);
+ }
+ }
+}
+
+/* Iterator Helpers proposal 2.1.5.8 */
+function IteratorReduce(reducer/*, initialValue*/) {
+ // Step 1.
+ const iterated = GetIteratorDirectWrapper(this);
+
+ // Step 2.
+ if (!IsCallable(reducer)) {
+ ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, reducer));
+ }
+
+ // Step 3.
+ let accumulator;
+ if (arguments.length === 1) {
+ // Step a.
+ const next = callContentFunction(iterated.next, iterated);
+ if (!IsObject(next)) {
+ ThrowTypeError(JSMSG_OBJECT_REQUIRED, DecompileArg(0, next));
+ }
+ // Step b.
+ if (next.done) {
+ ThrowTypeError(JSMSG_EMPTY_ITERATOR_REDUCE);
+ }
+ // Step c.
+ accumulator = next.value;
+ } else {
+ // Step 4.
+ accumulator = arguments[1];
+ }
+
+ // Step 5.
+ for (const value of allowContentIter(iterated)) {
+ accumulator = callContentFunction(reducer, undefined, accumulator, value);
+ }
+ return accumulator;
+}
+
+/* Iterator Helpers proposal 2.1.5.9 */
+function IteratorToArray() {
+ // Step 1.
+ const iterated = {[std_iterator]: () => this};
+ // Steps 2-3.
+ return [...allowContentIter(iterated)];
+}
+
+/* Iterator Helpers proposal 2.1.5.10 */
+function IteratorForEach(fn) {
+ // Step 1.
+ const iterated = GetIteratorDirectWrapper(this);
+
+ // Step 2.
+ if (!IsCallable(fn)) {
+ ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, fn));
+ }
+
+ // Step 3.
+ for (const value of allowContentIter(iterated)) {
+ callContentFunction(fn, undefined, value);
+ }
+}
+
+/* Iterator Helpers proposal 2.1.5.11 */
+function IteratorSome(fn) {
+ // Step 1.
+ const iterated = GetIteratorDirectWrapper(this);
+
+ // Step 2.
+ if (!IsCallable(fn)) {
+ ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, fn));
+ }
+
+ // Step 3.
+ for (const value of allowContentIter(iterated)) {
+ // Steps d-f.
+ if (callContentFunction(fn, undefined, value)) {
+ return true;
+ }
+ }
+ // Step 3b.
+ return false;
+}
+
+/* Iterator Helpers proposal 2.1.5.12 */
+function IteratorEvery(fn) {
+ // Step 1.
+ const iterated = GetIteratorDirectWrapper(this);
+
+ // Step 2.
+ if (!IsCallable(fn)) {
+ ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, fn));
+ }
+
+ // Step 3.
+ for (const value of allowContentIter(iterated)) {
+ // Steps d-f.
+ if (!callContentFunction(fn, undefined, value)) {
+ return false;
+ }
+ }
+ // Step 3b.
+ return true;
+}
+
+/* Iterator Helpers proposal 2.1.5.13 */
+function IteratorFind(fn) {
+ // Step 1.
+ const iterated = GetIteratorDirectWrapper(this);
+
+ // Step 2.
+ if (!IsCallable(fn)) {
+ ThrowTypeError(JSMSG_NOT_FUNCTION, DecompileArg(0, fn));
+ }
+
+ // Step 3.
+ for (const value of allowContentIter(iterated)) {
+ // Steps d-f.
+ if (callContentFunction(fn, undefined, value)) {
+ return value;
+ }
+ }
+}
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