IteratorOperations.cpp 5.6 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167
  1. /*
  2. * Copyright (c) 2020, Matthew Olsson <mattco@serenityos.org>
  3. *
  4. * SPDX-License-Identifier: BSD-2-Clause
  5. */
  6. #include <LibJS/Runtime/Error.h>
  7. #include <LibJS/Runtime/GlobalObject.h>
  8. #include <LibJS/Runtime/IteratorOperations.h>
  9. namespace JS {
  10. // 7.4.1 GetIterator ( obj [ , hint [ , method ] ] ), https://tc39.es/ecma262/#sec-getiterator
  11. Object* get_iterator(GlobalObject& global_object, Value value, IteratorHint hint, Value method)
  12. {
  13. auto& vm = global_object.vm();
  14. if (method.is_empty()) {
  15. if (hint == IteratorHint::Async)
  16. TODO();
  17. auto object = value.to_object(global_object);
  18. if (!object)
  19. return {};
  20. method = object->get(global_object.vm().well_known_symbol_iterator());
  21. if (vm.exception())
  22. return {};
  23. }
  24. if (!method.is_function()) {
  25. vm.throw_exception<TypeError>(global_object, ErrorType::NotIterable, value.to_string_without_side_effects());
  26. return nullptr;
  27. }
  28. auto iterator = vm.call(method.as_function(), value);
  29. if (vm.exception())
  30. return {};
  31. if (!iterator.is_object()) {
  32. vm.throw_exception<TypeError>(global_object, ErrorType::NotIterable, value.to_string_without_side_effects());
  33. return nullptr;
  34. }
  35. return &iterator.as_object();
  36. }
  37. // 7.4.2 IteratorNext ( iteratorRecord [ , value ] ), https://tc39.es/ecma262/#sec-iteratornext
  38. Object* iterator_next(Object& iterator, Value value)
  39. {
  40. auto& vm = iterator.vm();
  41. auto& global_object = iterator.global_object();
  42. auto next_method = iterator.get(vm.names.next);
  43. if (vm.exception())
  44. return {};
  45. if (!next_method.is_function()) {
  46. vm.throw_exception<TypeError>(global_object, ErrorType::IterableNextNotAFunction);
  47. return nullptr;
  48. }
  49. Value result;
  50. if (value.is_empty())
  51. result = vm.call(next_method.as_function(), &iterator);
  52. else
  53. result = vm.call(next_method.as_function(), &iterator, value);
  54. if (vm.exception())
  55. return {};
  56. if (!result.is_object()) {
  57. vm.throw_exception<TypeError>(global_object, ErrorType::IterableNextBadReturn);
  58. return nullptr;
  59. }
  60. return &result.as_object();
  61. }
  62. // 7.4.6 IteratorClose ( iteratorRecord, completion ), https://tc39.es/ecma262/#sec-iteratorclose
  63. void iterator_close(Object& iterator)
  64. {
  65. auto& vm = iterator.vm();
  66. auto& global_object = iterator.global_object();
  67. // Emulates `completion` behaviour
  68. auto* completion_exception = vm.exception();
  69. vm.clear_exception();
  70. auto unwind_until = vm.unwind_until();
  71. auto unwind_until_label = vm.unwind_until_label();
  72. vm.stop_unwind();
  73. auto restore_completion = [&]() {
  74. if (completion_exception)
  75. vm.set_exception(*completion_exception);
  76. if (unwind_until != ScopeType::None)
  77. vm.unwind(unwind_until, unwind_until_label);
  78. };
  79. auto return_method = get_method(global_object, &iterator, vm.names.return_);
  80. if (!return_method)
  81. return restore_completion(); // If return is undefined, return Completion(completion).
  82. auto result = vm.call(*return_method, &iterator);
  83. if (completion_exception)
  84. return restore_completion(); // If completion.[[Type]] is throw, return Completion(completion).
  85. if (vm.exception())
  86. return; // If innerResult.[[Type]] is throw, return Completion(innerResult).
  87. if (!result.is_object()) {
  88. vm.throw_exception<TypeError>(global_object, ErrorType::IterableReturnBadReturn);
  89. return; // If Type(innerResult.[[Value]]) is not Object, throw a TypeError exception.
  90. }
  91. restore_completion(); // Return Completion(completion).
  92. }
  93. // 7.4.10 IterableToList ( items [ , method ] ), https://tc39.es/ecma262/#sec-iterabletolist
  94. MarkedValueList iterable_to_list(GlobalObject& global_object, Value iterable, Value method)
  95. {
  96. auto& vm = global_object.vm();
  97. MarkedValueList values(vm.heap());
  98. get_iterator_values(
  99. global_object, iterable, [&](auto value) {
  100. if (vm.exception())
  101. return IterationDecision::Break;
  102. values.append(value);
  103. return IterationDecision::Continue;
  104. },
  105. method, CloseOnAbrupt::No);
  106. return values;
  107. }
  108. // 7.4.8 CreateIterResultObject ( value, done ), https://tc39.es/ecma262/#sec-createiterresultobject
  109. Value create_iterator_result_object(GlobalObject& global_object, Value value, bool done)
  110. {
  111. auto& vm = global_object.vm();
  112. auto* object = Object::create(global_object, global_object.object_prototype());
  113. object->define_property(vm.names.value, value);
  114. object->define_property(vm.names.done, Value(done));
  115. return object;
  116. }
  117. void get_iterator_values(GlobalObject& global_object, Value value, AK::Function<IterationDecision(Value)> callback, Value method, CloseOnAbrupt close_on_abrupt)
  118. {
  119. auto& vm = global_object.vm();
  120. auto iterator = get_iterator(global_object, value, IteratorHint::Sync, method);
  121. if (!iterator)
  122. return;
  123. while (true) {
  124. auto next_object = iterator_next(*iterator);
  125. if (!next_object)
  126. return;
  127. auto done_property = next_object->get(vm.names.done);
  128. if (vm.exception())
  129. return;
  130. if (!done_property.is_empty() && done_property.to_boolean())
  131. return;
  132. auto next_value = next_object->get(vm.names.value);
  133. if (vm.exception())
  134. return;
  135. auto result = callback(next_value);
  136. if (result == IterationDecision::Break) {
  137. if (close_on_abrupt == CloseOnAbrupt::Yes)
  138. iterator_close(*iterator);
  139. return;
  140. }
  141. VERIFY(result == IterationDecision::Continue);
  142. }
  143. }
  144. }