ReadableStreamDefaultReader.cpp 9.6 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/Fetch/Infrastructure/IncrementalReadLoopReadRequest.h>
  18. #include <LibWeb/Streams/AbstractOperations.h>
  19. #include <LibWeb/Streams/ReadableStream.h>
  20. #include <LibWeb/Streams/ReadableStreamDefaultReader.h>
  21. #include <LibWeb/WebIDL/ExceptionOr.h>
  22. #include <LibWeb/WebIDL/Promise.h>
  23. namespace Web::Streams {
  24. JS_DEFINE_ALLOCATOR(ReadableStreamDefaultReader);
  25. JS_DEFINE_ALLOCATOR(ReadLoopReadRequest);
  26. void ReadLoopReadRequest::visit_edges(Visitor& visitor)
  27. {
  28. Base::visit_edges(visitor);
  29. visitor.visit(m_realm);
  30. visitor.visit(m_reader);
  31. }
  32. // https://streams.spec.whatwg.org/#default-reader-constructor
  33. WebIDL::ExceptionOr<JS::NonnullGCPtr<ReadableStreamDefaultReader>> ReadableStreamDefaultReader::construct_impl(JS::Realm& realm, JS::NonnullGCPtr<ReadableStream> stream)
  34. {
  35. auto reader = realm.heap().allocate<ReadableStreamDefaultReader>(realm, realm);
  36. // 1. Perform ? SetUpReadableStreamDefaultReader(this, stream);
  37. TRY(set_up_readable_stream_default_reader(reader, *stream));
  38. return reader;
  39. }
  40. ReadableStreamDefaultReader::ReadableStreamDefaultReader(JS::Realm& realm)
  41. : Bindings::PlatformObject(realm)
  42. , ReadableStreamGenericReaderMixin(realm)
  43. {
  44. }
  45. void ReadableStreamDefaultReader::initialize(JS::Realm& realm)
  46. {
  47. Base::initialize(realm);
  48. WEB_SET_PROTOTYPE_FOR_INTERFACE(ReadableStreamDefaultReader);
  49. }
  50. void ReadableStreamDefaultReader::visit_edges(Cell::Visitor& visitor)
  51. {
  52. Base::visit_edges(visitor);
  53. ReadableStreamGenericReaderMixin::visit_edges(visitor);
  54. for (auto& request : m_read_requests)
  55. visitor.visit(request);
  56. }
  57. // https://streams.spec.whatwg.org/#read-loop
  58. ReadLoopReadRequest::ReadLoopReadRequest(JS::VM& vm, JS::Realm& realm, ReadableStreamDefaultReader& reader, SuccessSteps success_steps, FailureSteps failure_steps, ChunkSteps chunk_steps)
  59. : m_vm(vm)
  60. , m_realm(realm)
  61. , m_reader(reader)
  62. , m_success_steps(move(success_steps))
  63. , m_failure_steps(move(failure_steps))
  64. , m_chunk_steps(move(chunk_steps))
  65. {
  66. }
  67. // chunk steps, given chunk
  68. void ReadLoopReadRequest::on_chunk(JS::Value chunk)
  69. {
  70. // 1. If chunk is not a Uint8Array object, call failureSteps with a TypeError and abort these steps.
  71. if (!chunk.is_object() || !is<JS::Uint8Array>(chunk.as_object())) {
  72. m_failure_steps(JS::TypeError::create(m_realm, "Chunk data is not Uint8Array"sv));
  73. return;
  74. }
  75. auto const& array = static_cast<JS::Uint8Array const&>(chunk.as_object());
  76. auto const& buffer = array.viewed_array_buffer()->buffer();
  77. // 2. Append the bytes represented by chunk to bytes.
  78. m_bytes.append(buffer);
  79. if (m_chunk_steps) {
  80. // FIXME: Can we move the buffer out of the `chunk`? Unclear if that is safe.
  81. m_chunk_steps(MUST(ByteBuffer::copy(buffer)));
  82. }
  83. // FIXME: As the spec suggests, implement this non-recursively - instead of directly. It is not too big of a deal currently
  84. // as we enqueue the entire blob buffer in one go, meaning that we only recurse a single time. Once we begin queuing
  85. // up more than one chunk at a time, we may run into stack overflow problems.
  86. //
  87. // 3. Read-loop given reader, bytes, successSteps, and failureSteps.
  88. readable_stream_default_reader_read(m_reader, *this);
  89. }
  90. // close steps
  91. void ReadLoopReadRequest::on_close()
  92. {
  93. // 1. Call successSteps with bytes.
  94. m_success_steps(move(m_bytes));
  95. }
  96. // error steps, given e
  97. void ReadLoopReadRequest::on_error(JS::Value error)
  98. {
  99. // 1. Call failureSteps with e.
  100. m_failure_steps(error);
  101. }
  102. class DefaultReaderReadRequest final : public ReadRequest {
  103. JS_CELL(DefaultReaderReadRequest, ReadRequest);
  104. JS_DECLARE_ALLOCATOR(DefaultReaderReadRequest);
  105. public:
  106. DefaultReaderReadRequest(JS::Realm& realm, WebIDL::Promise& promise)
  107. : m_realm(realm)
  108. , m_promise(promise)
  109. {
  110. }
  111. virtual void on_chunk(JS::Value chunk) override
  112. {
  113. WebIDL::resolve_promise(m_realm, m_promise, JS::create_iterator_result_object(m_realm->vm(), chunk, false));
  114. }
  115. virtual void on_close() override
  116. {
  117. WebIDL::resolve_promise(m_realm, m_promise, JS::create_iterator_result_object(m_realm->vm(), JS::js_undefined(), true));
  118. }
  119. virtual void on_error(JS::Value error) override
  120. {
  121. WebIDL::reject_promise(m_realm, m_promise, error);
  122. }
  123. private:
  124. virtual void visit_edges(Visitor& visitor) override
  125. {
  126. Base::visit_edges(visitor);
  127. visitor.visit(m_realm);
  128. visitor.visit(m_promise);
  129. }
  130. JS::NonnullGCPtr<JS::Realm> m_realm;
  131. JS::NonnullGCPtr<WebIDL::Promise> m_promise;
  132. };
  133. JS_DEFINE_ALLOCATOR(DefaultReaderReadRequest);
  134. // https://streams.spec.whatwg.org/#default-reader-read
  135. JS::NonnullGCPtr<JS::Promise> ReadableStreamDefaultReader::read()
  136. {
  137. auto& realm = this->realm();
  138. // 1. If this.[[stream]] is undefined, return a promise rejected with a TypeError exception.
  139. if (!m_stream) {
  140. WebIDL::SimpleException exception { WebIDL::SimpleExceptionType::TypeError, "Cannot read from an empty stream"sv };
  141. return WebIDL::create_rejected_promise_from_exception(realm, move(exception));
  142. }
  143. // 2. Let promise be a new promise.
  144. auto promise_capability = WebIDL::create_promise(realm);
  145. // 3. Let readRequest be a new read request with the following items:
  146. // chunk steps, given chunk
  147. // Resolve promise with «[ "value" → chunk, "done" → false ]».
  148. // close steps
  149. // Resolve promise with «[ "value" → undefined, "done" → true ]».
  150. // error steps, given e
  151. // Reject promise with e.
  152. auto read_request = heap().allocate_without_realm<DefaultReaderReadRequest>(realm, promise_capability);
  153. // 4. Perform ! ReadableStreamDefaultReaderRead(this, readRequest).
  154. readable_stream_default_reader_read(*this, read_request);
  155. // 5. Return promise.
  156. return JS::NonnullGCPtr { verify_cast<JS::Promise>(*promise_capability->promise()) };
  157. }
  158. void ReadableStreamDefaultReader::read_a_chunk(Fetch::Infrastructure::IncrementalReadLoopReadRequest& read_request)
  159. {
  160. // To read a chunk from a ReadableStreamDefaultReader reader, given a read request readRequest,
  161. // perform ! ReadableStreamDefaultReaderRead(reader, readRequest).
  162. readable_stream_default_reader_read(*this, read_request);
  163. }
  164. // https://streams.spec.whatwg.org/#readablestreamdefaultreader-read-all-bytes
  165. void ReadableStreamDefaultReader::read_all_bytes(ReadLoopReadRequest::SuccessSteps success_steps, ReadLoopReadRequest::FailureSteps failure_steps)
  166. {
  167. auto& realm = this->realm();
  168. auto& vm = realm.vm();
  169. // 1. Let readRequest be a new read request with the following items:
  170. // NOTE: items and steps in ReadLoopReadRequest.
  171. auto read_request = heap().allocate_without_realm<ReadLoopReadRequest>(vm, realm, *this, move(success_steps), move(failure_steps));
  172. // 2. Perform ! ReadableStreamDefaultReaderRead(this, readRequest).
  173. readable_stream_default_reader_read(*this, read_request);
  174. }
  175. void ReadableStreamDefaultReader::read_all_chunks(ReadLoopReadRequest::ChunkSteps chunk_steps, ReadLoopReadRequest::SuccessSteps success_steps, ReadLoopReadRequest::FailureSteps failure_steps)
  176. {
  177. // AD-HOC: Some spec steps direct us to "read all chunks" from a stream, but there isn't an AO defined to do that.
  178. // We implement those steps by using the "read all bytes" definition, with a custom callback to receive
  179. // each chunk that is read.
  180. auto& realm = this->realm();
  181. auto& vm = realm.vm();
  182. // 1. Let readRequest be a new read request with the following items:
  183. // NOTE: items and steps in ReadLoopReadRequest.
  184. auto read_request = heap().allocate_without_realm<ReadLoopReadRequest>(vm, realm, *this, move(success_steps), move(failure_steps), move(chunk_steps));
  185. // 2. Perform ! ReadableStreamDefaultReaderRead(this, readRequest).
  186. readable_stream_default_reader_read(*this, read_request);
  187. }
  188. // FIXME: This function is a promise-based wrapper around "read all bytes". The spec changed this function to not use promises
  189. // in https://github.com/whatwg/streams/commit/f894acdd417926a2121710803cef593e15127964 - however, it seems that the
  190. // FileAPI blob specification has not been updated to match, see: https://github.com/w3c/FileAPI/issues/187.
  191. JS::NonnullGCPtr<WebIDL::Promise> ReadableStreamDefaultReader::read_all_bytes_deprecated()
  192. {
  193. auto& realm = this->realm();
  194. auto promise = WebIDL::create_promise(realm);
  195. auto success_steps = [promise, &realm](ByteBuffer bytes) {
  196. auto buffer = JS::ArrayBuffer::create(realm, move(bytes));
  197. WebIDL::resolve_promise(realm, promise, buffer);
  198. };
  199. auto failure_steps = [promise, &realm](JS::Value error) {
  200. WebIDL::reject_promise(realm, promise, error);
  201. };
  202. read_all_bytes(move(success_steps), move(failure_steps));
  203. return promise;
  204. }
  205. // https://streams.spec.whatwg.org/#default-reader-release-lock
  206. void ReadableStreamDefaultReader::release_lock()
  207. {
  208. // 1. If this.[[stream]] is undefined, return.
  209. if (!m_stream)
  210. return;
  211. // 2. Perform ! ReadableStreamDefaultReaderRelease(this).
  212. readable_stream_default_reader_release(*this);
  213. }
  214. }