Add WebIDL files for ReadableStreamBYOBReader

This CL adds the WebIDL files and relevant C++ stubs for
the ReadableStreamBYOBReader class according the the Streams
API Standard[1]. It also adds a ReadableStreamBYOBReadResult
dictionary needed by the read() function in the reader.

This feature will be runtime enabled under the flag
"ReadableByteStream".

[1] https://streams.spec.whatwg.org/#readablestreambyobreader

Bug: 614302
Change-Id: I91fea585574e12bc868bf35931c6e0783177e687
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2513952
Commit-Queue: Nidhi Jaju <nidhijaju@google.com>
Reviewed-by: Yutaka Hirano <yhirano@chromium.org>
Reviewed-by: Adam Rice <ricea@chromium.org>
Cr-Commit-Position: refs/heads/master@{#823912}

third_party/blink/renderer/bindings/generated_in_core.gni

@@ -271,6 +271,8 @@ generated_dictionary_sources_in_core = [
   "$root_gen_dir/third_party/blink/renderer/bindings/core/v8/v8_property_definition.h",
   "$root_gen_dir/third_party/blink/renderer/bindings/core/v8/v8_queuing_strategy_init.cc",
   "$root_gen_dir/third_party/blink/renderer/bindings/core/v8/v8_queuing_strategy_init.h",
+  "$root_gen_dir/third_party/blink/renderer/bindings/core/v8/v8_readable_stream_byob_read_result.cc",
+  "$root_gen_dir/third_party/blink/renderer/bindings/core/v8/v8_readable_stream_byob_read_result.h",
   "$root_gen_dir/third_party/blink/renderer/bindings/core/v8/v8_readable_writable_pair.cc",
   "$root_gen_dir/third_party/blink/renderer/bindings/core/v8/v8_readable_writable_pair.h",
   "$root_gen_dir/third_party/blink/renderer/bindings/core/v8/v8_reporting_observer_options.cc",
@@ -1025,6 +1027,8 @@ generated_interface_sources_in_core = [
   "$root_gen_dir/third_party/blink/renderer/bindings/core/v8/v8_range.h",
   "$root_gen_dir/third_party/blink/renderer/bindings/core/v8/v8_readable_stream.cc",
   "$root_gen_dir/third_party/blink/renderer/bindings/core/v8/v8_readable_stream.h",
+  "$root_gen_dir/third_party/blink/renderer/bindings/core/v8/v8_readable_stream_byob_reader.cc",
+  "$root_gen_dir/third_party/blink/renderer/bindings/core/v8/v8_readable_stream_byob_reader.h",
   "$root_gen_dir/third_party/blink/renderer/bindings/core/v8/v8_readable_stream_default_controller.cc",
   "$root_gen_dir/third_party/blink/renderer/bindings/core/v8/v8_readable_stream_default_controller.h",
   "$root_gen_dir/third_party/blink/renderer/bindings/core/v8/v8_readable_stream_default_reader.cc",

third_party/blink/renderer/bindings/idl_in_core.gni

@@ -484,6 +484,8 @@ static_idl_files_in_core = get_path_info(
           "//third_party/blink/renderer/core/streams/count_queuing_strategy.idl",
           "//third_party/blink/renderer/core/streams/queuing_strategy_init.idl",
           "//third_party/blink/renderer/core/streams/readable_stream.idl",
+          "//third_party/blink/renderer/core/streams/readable_stream_byob_reader.idl",
+          "//third_party/blink/renderer/core/streams/readable_stream_byob_read_result.idl",
           "//third_party/blink/renderer/core/streams/readable_stream_default_controller.idl",
           "//third_party/blink/renderer/core/streams/readable_stream_default_reader.idl",
           "//third_party/blink/renderer/core/streams/readable_writable_pair.idl",

third_party/blink/renderer/core/core_idl_files.gni

@@ -334,6 +334,7 @@ core_interface_idl_files_core_only =
                     "streams/byte_length_queuing_strategy.idl",
                     "streams/count_queuing_strategy.idl",
                     "streams/readable_stream.idl",
+                    "streams/readable_stream_byob_reader.idl",
                     "streams/readable_stream_default_controller.idl",
                     "streams/readable_stream_default_reader.idl",
                     "streams/transform_stream.idl",
@@ -736,6 +737,7 @@ core_dictionary_idl_files =
                     "mojo/test/mojo_interface_request_event_init.idl",
                     "page/scrolling/scroll_state_init.idl",
                     "resize_observer/resize_observer_options.idl",
+                    "streams/readable_stream_byob_read_result.idl",
                     "streams/readable_writable_pair.idl",
                     "streams/stream_pipe_options.idl",
                     "streams/queuing_strategy_init.idl",

third_party/blink/renderer/core/streams/build.gni

@@ -17,6 +17,8 @@ blink_core_sources_streams = [
   "queuing_strategy_common.h",
   "readable_stream.cc",
   "readable_stream.h",
+  "readable_stream_byob_reader.cc",
+  "readable_stream_byob_reader.h",
   "readable_stream_default_controller.cc",
   "readable_stream_default_controller.h",
   "readable_stream_default_controller_with_script_scope.cc",

third_party/blink/renderer/core/streams/readable_stream_byob_read_result.idl

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// https://streams.spec.whatwg.org/#dictdef-readablestreambyobreadresult
+
+dictionary ReadableStreamBYOBReadResult {
+  ArrayBufferView value;
+  boolean done;
+};

third_party/blink/renderer/core/streams/readable_stream_byob_reader.cc

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "third_party/blink/renderer/core/streams/readable_stream_byob_reader.h"
+
+#include "third_party/blink/renderer/bindings/core/v8/script_promise.h"
+#include "third_party/blink/renderer/core/streams/stream_promise_resolver.h"
+#include "third_party/blink/renderer/core/typed_arrays/dom_array_buffer_view.h"
+#include "third_party/blink/renderer/platform/bindings/exception_state.h"
+#include "third_party/blink/renderer/platform/bindings/script_state.h"
+#include "third_party/blink/renderer/platform/bindings/v8_binding.h"
+
+namespace blink {
+
+ReadableStreamBYOBReader* ReadableStreamBYOBReader::Create(
+    ScriptState* script_state,
+    ReadableStream* stream,
+    ExceptionState& exception_state) {
+  ThrowUnimplemented(exception_state);
+  return nullptr;
+}
+
+ReadableStreamBYOBReader::ReadableStreamBYOBReader(
+    ScriptState* script_state,
+    ReadableStream* stream,
+    ExceptionState& exception_state) {
+  ThrowUnimplemented(exception_state);
+  return;
+}
+
+ReadableStreamBYOBReader::~ReadableStreamBYOBReader() = default;
+
+ScriptPromise ReadableStreamBYOBReader::read(ScriptState* script_state,
+                                             NotShared<DOMArrayBufferView> view,
+                                             ExceptionState& exception_state) {
+  return RejectUnimplemented(script_state);
+}
+
+void ReadableStreamBYOBReader::releaseLock(ScriptState* script_state,
+                                           ExceptionState& exception_state) {
+  ThrowUnimplemented(exception_state);
+  return;
+}
+
+ScriptPromise ReadableStreamBYOBReader::closed(
+    ScriptState* script_state) const {
+  return RejectUnimplemented(script_state);
+}
+
+ScriptPromise ReadableStreamBYOBReader::cancel(
+    ScriptState* script_state,
+    ExceptionState& exception_state) {
+  return RejectUnimplemented(script_state);
+}
+
+ScriptPromise ReadableStreamBYOBReader::cancel(
+    ScriptState* script_state,
+    ScriptValue reason,
+    ExceptionState& exception_state) {
+  return RejectUnimplemented(script_state);
+}
+
+void ReadableStreamBYOBReader::ThrowUnimplemented(
+    ExceptionState& exception_state) {
+  exception_state.ThrowTypeError("unimplemented");
+}
+
+ScriptPromise ReadableStreamBYOBReader::RejectUnimplemented(
+    ScriptState* script_state) {
+  return StreamPromiseResolver::CreateRejected(
+             script_state, v8::Exception::TypeError(V8String(
+                               script_state->GetIsolate(), "unimplemented")))
+      ->GetScriptPromise(script_state);
+}
+
+}  // namespace blink

third_party/blink/renderer/core/streams/readable_stream_byob_reader.h

+// Copyright 2020 The Chromium AUthors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be found
+// in the LICENSE file.
+
+#ifndef THIRD_PARTY_BLINK_RENDERER_CORE_STREAMS_READABLE_STREAM_BYOB_READER_H_
+#define THIRD_PARTY_BLINK_RENDERER_CORE_STREAMS_READABLE_STREAM_BYOB_READER_H_
+
+#include "third_party/blink/renderer/bindings/core/v8/script_value.h"
+#include "third_party/blink/renderer/core/core_export.h"
+#include "third_party/blink/renderer/core/typed_arrays/array_buffer_view_helpers.h"
+#include "third_party/blink/renderer/platform/bindings/script_wrappable.h"
+
+namespace blink {
+
+class ExceptionState;
+class ScriptPromise;
+class ScriptState;
+class ReadableStream;
+class DOMArrayBufferView;
+
+class CORE_EXPORT ReadableStreamBYOBReader : public ScriptWrappable {
+  DEFINE_WRAPPERTYPEINFO();
+
+ public:
+  static ReadableStreamBYOBReader* Create(ScriptState*,
+                                          ReadableStream* stream,
+                                          ExceptionState&);
+
+  // https://streams.spec.whatwg.org/#byob-reader-constructor
+  ReadableStreamBYOBReader(ScriptState*,
+                           ReadableStream* stream,
+                           ExceptionState&);
+  ~ReadableStreamBYOBReader() override;
+
+  // https://streams.spec.whatwg.org/#byob-reader-read
+  ScriptPromise read(ScriptState*,
+                     NotShared<DOMArrayBufferView> view,
+                     ExceptionState&);
+
+  // https://streams.spec.whatwg.org/#byob-reader-release-lock
+  void releaseLock(ScriptState*, ExceptionState&);
+
+  // https://streams.spec.whatwg.org/#generic-reader-closed
+  ScriptPromise closed(ScriptState*) const;
+
+  // https://streams.spec.whatwg.org/#generic-reader-cancel
+  ScriptPromise cancel(ScriptState*, ExceptionState&);
+  ScriptPromise cancel(ScriptState*, ScriptValue reason, ExceptionState&);
+
+ private:
+  friend class ReadableStream;
+  static void ThrowUnimplemented(ExceptionState&);
+  static ScriptPromise RejectUnimplemented(ScriptState*);
+};
+}  // namespace blink
+
+#endif  // THIRD_PARTY_BLINK_RENDERER_CORE_STREAMS_READABLE_STREAM_BYOB_READER_H_

third_party/blink/renderer/core/streams/readable_stream_byob_reader.idl

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// https://streams.spec.whatwg.org/#byob-reader-class-definition
+[
+    Exposed=(Window,Worker,Worklet),
+    RuntimeEnabled=ReadableByteStream
+] interface ReadableStreamBYOBReader {
+    [CallWith=ScriptState, RaisesException] constructor(ReadableStream stream);
+
+    [CallWith=ScriptState, RaisesException] Promise<ReadableStreamBYOBReadResult> read(ArrayBufferView view);
+    [CallWith=ScriptState, RaisesException] void releaseLock();
+
+    // includes ReadableStreamGenericReader
+    [CallWith=ScriptState] readonly attribute Promise<void> closed;
+    [CallWith=ScriptState, RaisesException] Promise<void> cancel(optional any reason);
+};

third_party/blink/renderer/platform/runtime_enabled_features.json5

@@ -1605,6 +1605,9 @@
       // Enabled when blink::features::kRawClipboard is enabled.
       name: "RawClipboard",
     },
+    {
+      name: "ReadableByteStream",
+    },
     {
       name: "RemotePlayback",
       status: "stable",