ReadableStreamDefaultReader.cpp 8.3 KB

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  1. /*
  2. * Copyright (c) 2023, Matthew Olsson <mattco@serenityos.org>
  3. * Copyright (c) 2023, Shannon Booth <shannon@serenityos.org>
  4. *
  5. * SPDX-License-Identifier: BSD-2-Clause
  6. */
  7. #include <LibJS/Heap/Heap.h>
  8. #include <LibJS/Runtime/ArrayBuffer.h>
  9. #include <LibJS/Runtime/Error.h>
  10. #include <LibJS/Runtime/Iterator.h>
  11. #include <LibJS/Runtime/PromiseCapability.h>
  12. #include <LibJS/Runtime/Realm.h>
  13. #include <LibJS/Runtime/TypedArray.h>
  14. #include <LibWeb/Bindings/ExceptionOrUtils.h>
  15. #include <LibWeb/Bindings/Intrinsics.h>
  16. #include <LibWeb/Bindings/ReadableStreamDefaultReaderPrototype.h>
  17. #include <LibWeb/Streams/AbstractOperations.h>
  18. #include <LibWeb/Streams/ReadableStream.h>
  19. #include <LibWeb/Streams/ReadableStreamDefaultReader.h>
  20. #include <LibWeb/WebIDL/ExceptionOr.h>
  21. #include <LibWeb/WebIDL/Promise.h>
  22. namespace Web::Streams {
  23. void ReadLoopReadRequest::visit_edges(Visitor& visitor)
  24. {
  25. Base::visit_edges(visitor);
  26. visitor.visit(m_realm);
  27. visitor.visit(m_reader);
  28. }
  29. // https://streams.spec.whatwg.org/#default-reader-constructor
  30. WebIDL::ExceptionOr<JS::NonnullGCPtr<ReadableStreamDefaultReader>> ReadableStreamDefaultReader::construct_impl(JS::Realm& realm, JS::NonnullGCPtr<ReadableStream> stream)
  31. {
  32. auto reader = realm.heap().allocate<ReadableStreamDefaultReader>(realm, realm);
  33. // 1. Perform ? SetUpReadableStreamDefaultReader(this, stream);
  34. TRY(set_up_readable_stream_default_reader(reader, *stream));
  35. return reader;
  36. }
  37. ReadableStreamDefaultReader::ReadableStreamDefaultReader(JS::Realm& realm)
  38. : Bindings::PlatformObject(realm)
  39. , ReadableStreamGenericReaderMixin(realm)
  40. {
  41. }
  42. void ReadableStreamDefaultReader::initialize(JS::Realm& realm)
  43. {
  44. Base::initialize(realm);
  45. set_prototype(&Bindings::ensure_web_prototype<Bindings::ReadableStreamDefaultReaderPrototype>(realm, "ReadableStreamDefaultReader"));
  46. }
  47. void ReadableStreamDefaultReader::visit_edges(Cell::Visitor& visitor)
  48. {
  49. Base::visit_edges(visitor);
  50. ReadableStreamGenericReaderMixin::visit_edges(visitor);
  51. for (auto& request : m_read_requests)
  52. visitor.visit(request);
  53. }
  54. // https://streams.spec.whatwg.org/#read-loop
  55. ReadLoopReadRequest::ReadLoopReadRequest(JS::VM& vm, JS::Realm& realm, ReadableStreamDefaultReader& reader, SuccessSteps success_steps, FailureSteps failure_steps)
  56. : m_vm(vm)
  57. , m_realm(realm)
  58. , m_reader(reader)
  59. , m_success_steps(move(success_steps))
  60. , m_failure_steps(move(failure_steps))
  61. {
  62. }
  63. // chunk steps, given chunk
  64. void ReadLoopReadRequest::on_chunk(JS::Value chunk)
  65. {
  66. // 1. If chunk is not a Uint8Array object, call failureSteps with a TypeError and abort these steps.
  67. if (!chunk.is_object() || !is<JS::Uint8Array>(chunk.as_object())) {
  68. m_failure_steps(JS::TypeError::create(m_realm, "Chunk data is not Uint8Array"sv));
  69. return;
  70. }
  71. auto const& array = static_cast<JS::Uint8Array const&>(chunk.as_object());
  72. auto const& buffer = array.viewed_array_buffer()->buffer();
  73. // 2. Append the bytes represented by chunk to bytes.
  74. m_bytes.append(buffer);
  75. // FIXME: As the spec suggests, implement this non-recursively - instead of directly. It is not too big of a deal currently
  76. // as we enqueue the entire blob buffer in one go, meaning that we only recurse a single time. Once we begin queuing
  77. // up more than one chunk at a time, we may run into stack overflow problems.
  78. //
  79. // 3. Read-loop given reader, bytes, successSteps, and failureSteps.
  80. auto maybe_error = readable_stream_default_reader_read(m_reader, *this);
  81. if (maybe_error.is_exception()) {
  82. auto throw_completion = Bindings::dom_exception_to_throw_completion(m_vm, maybe_error.exception());
  83. m_failure_steps(*throw_completion.release_error().value());
  84. }
  85. }
  86. // close steps
  87. void ReadLoopReadRequest::on_close()
  88. {
  89. // 1. Call successSteps with bytes.
  90. m_success_steps(m_bytes);
  91. }
  92. // error steps, given e
  93. void ReadLoopReadRequest::on_error(JS::Value error)
  94. {
  95. // 1. Call failureSteps with e.
  96. m_failure_steps(error);
  97. }
  98. class DefaultReaderReadRequest final : public ReadRequest {
  99. JS_CELL(DefaultReaderReadRequest, Cell);
  100. public:
  101. DefaultReaderReadRequest(JS::Realm& realm, WebIDL::Promise& promise)
  102. : m_realm(realm)
  103. , m_promise(promise)
  104. {
  105. }
  106. virtual void on_chunk(JS::Value chunk) override
  107. {
  108. WebIDL::resolve_promise(m_realm, m_promise, JS::create_iterator_result_object(m_realm.vm(), chunk, false));
  109. }
  110. virtual void on_close() override
  111. {
  112. WebIDL::resolve_promise(m_realm, m_promise, JS::create_iterator_result_object(m_realm.vm(), JS::js_undefined(), true));
  113. }
  114. virtual void on_error(JS::Value error) override
  115. {
  116. WebIDL::reject_promise(m_realm, m_promise, error);
  117. }
  118. private:
  119. virtual void visit_edges(Visitor& visitor) override
  120. {
  121. Base::visit_edges(visitor);
  122. visitor.visit(m_realm);
  123. visitor.visit(m_promise);
  124. }
  125. JS::Realm& m_realm;
  126. WebIDL::Promise& m_promise;
  127. };
  128. // https://streams.spec.whatwg.org/#default-reader-read
  129. WebIDL::ExceptionOr<JS::NonnullGCPtr<JS::Promise>> ReadableStreamDefaultReader::read()
  130. {
  131. auto& realm = this->realm();
  132. // 1. If this.[[stream]] is undefined, return a promise rejected with a TypeError exception.
  133. if (!m_stream) {
  134. auto exception = JS::TypeError::create(realm, "Cannot read from an empty stream"sv);
  135. auto promise_capability = WebIDL::create_rejected_promise(realm, exception);
  136. return JS::NonnullGCPtr { verify_cast<JS::Promise>(*promise_capability->promise()) };
  137. }
  138. // 2. Let promise be a new promise.
  139. auto promise_capability = WebIDL::create_promise(realm);
  140. // 3. Let readRequest be a new read request with the following items:
  141. // chunk steps, given chunk
  142. // Resolve promise with «[ "value" → chunk, "done" → false ]».
  143. // close steps
  144. // Resolve promise with «[ "value" → undefined, "done" → true ]».
  145. // error steps, given e
  146. // Reject promise with e.
  147. auto read_request = heap().allocate_without_realm<DefaultReaderReadRequest>(realm, promise_capability);
  148. // 4. Perform ! ReadableStreamDefaultReaderRead(this, readRequest).
  149. TRY(readable_stream_default_reader_read(*this, read_request));
  150. // 5. Return promise.
  151. return JS::NonnullGCPtr { verify_cast<JS::Promise>(*promise_capability->promise()) };
  152. }
  153. // https://streams.spec.whatwg.org/#readablestreamdefaultreader-read-all-bytes
  154. WebIDL::ExceptionOr<void> ReadableStreamDefaultReader::read_all_bytes(ReadLoopReadRequest::SuccessSteps success_steps, ReadLoopReadRequest::FailureSteps failure_steps)
  155. {
  156. auto& realm = this->realm();
  157. auto& vm = realm.vm();
  158. // 1. Let readRequest be a new read request with the following items:
  159. // NOTE: items and steps in ReadLoopReadRequest.
  160. auto read_request = heap().allocate_without_realm<ReadLoopReadRequest>(vm, realm, *this, move(success_steps), move(failure_steps));
  161. // 2. Perform ! ReadableStreamDefaultReaderRead(this, readRequest).
  162. TRY(readable_stream_default_reader_read(*this, read_request));
  163. return {};
  164. }
  165. // FIXME: This function is a promise-based wrapper around "read all bytes". The spec changed this function to not use promises
  166. // in https://github.com/whatwg/streams/commit/f894acdd417926a2121710803cef593e15127964 - however, it seems that the
  167. // FileAPI blob specification has not been updated to match, see: https://github.com/w3c/FileAPI/issues/187.
  168. WebIDL::ExceptionOr<JS::NonnullGCPtr<WebIDL::Promise>> ReadableStreamDefaultReader::read_all_bytes_deprecated()
  169. {
  170. auto& realm = this->realm();
  171. auto promise = WebIDL::create_promise(realm);
  172. auto success_steps = [promise, &realm](ByteBuffer bytes) {
  173. auto buffer = JS::ArrayBuffer::create(realm, move(bytes));
  174. WebIDL::resolve_promise(realm, promise, buffer);
  175. };
  176. auto failure_steps = [promise, &realm](JS::Value error) {
  177. WebIDL::reject_promise(realm, promise, error);
  178. };
  179. TRY(read_all_bytes(move(success_steps), move(failure_steps)));
  180. return promise;
  181. }
  182. // https://streams.spec.whatwg.org/#default-reader-release-lock
  183. WebIDL::ExceptionOr<void> ReadableStreamDefaultReader::release_lock()
  184. {
  185. // 1. If this.[[stream]] is undefined, return.
  186. if (!m_stream)
  187. return {};
  188. // 2. Perform ! ReadableStreamDefaultReaderRelease(this).
  189. return readable_stream_default_reader_release(*this);
  190. }
  191. }