third_party/WebKit/Source/core/streams/ReadableStreamController.h

// Copyright 2016 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 ReadableStreamController_h
#define ReadableStreamController_h

#include "bindings/core/v8/ScopedPersistent.h"
#include "bindings/core/v8/ScriptValue.h"
#include "bindings/core/v8/ToV8.h"
#include "bindings/core/v8/V8ScriptRunner.h"
#include "core/CoreExport.h"
#include "platform/heap/Handle.h"
#include "wtf/RefPtr.h"
#include <v8.h>

namespace blink {

// TODO(tyoshino): Rename this to ReadableStreamDefaultControllerWrapper.
class CORE_EXPORT ReadableStreamController final
    : public GarbageCollectedFinalized<ReadableStreamController> {
 public:
  DEFINE_INLINE_TRACE() {}

  explicit ReadableStreamController(ScriptValue controller)
      : m_scriptState(controller.getScriptState()),
        m_jsController(controller.isolate(), controller.v8Value()) {
    m_jsController.setPhantom();
  }

  // Users of the ReadableStreamController can call this to note that the stream
  // has been canceled and thus they don't anticipate using the
  // ReadableStreamController anymore.  (close/desiredSize/enqueue/error will
  // become no-ops afterward.)
  void noteHasBeenCanceled() { m_jsController.clear(); }

  bool isActive() const { return !m_jsController.isEmpty(); }

  void close() {
    ScriptState* scriptState = m_scriptState.get();
    // This will assert that the context is valid; do not call this method when
    // the context is invalidated.
    ScriptState::Scope scope(scriptState);
    v8::Isolate* isolate = scriptState->isolate();

    v8::Local<v8::Value> controller = m_jsController.newLocal(isolate);
    if (controller.IsEmpty())
      return;

    v8::Local<v8::Value> args[] = {controller};
    v8::MaybeLocal<v8::Value> result = V8ScriptRunner::callExtra(
        scriptState, "ReadableStreamDefaultControllerClose", args);
    m_jsController.clear();
    result.ToLocalChecked();
  }

  double desiredSize() const {
    ScriptState* scriptState = m_scriptState.get();
    // This will assert that the context is valid; do not call this method when
    // the context is invalidated.
    ScriptState::Scope scope(scriptState);
    v8::Isolate* isolate = scriptState->isolate();

    v8::Local<v8::Value> controller = m_jsController.newLocal(isolate);
    if (controller.IsEmpty())
      return 0;

    v8::Local<v8::Value> args[] = {controller};
    v8::MaybeLocal<v8::Value> result = V8ScriptRunner::callExtra(
        scriptState, "ReadableStreamDefaultControllerGetDesiredSize", args);

    return result.ToLocalChecked().As<v8::Number>()->Value();
  }

  template <typename ChunkType>
  void enqueue(ChunkType chunk) const {
    ScriptState* scriptState = m_scriptState.get();
    // This will assert that the context is valid; do not call this method when
    // the context is invalidated.
    ScriptState::Scope scope(scriptState);
    v8::Isolate* isolate = scriptState->isolate();

    v8::Local<v8::Value> controller = m_jsController.newLocal(isolate);
    if (controller.IsEmpty())
      return;

    v8::Local<v8::Value> jsChunk = toV8(chunk, scriptState);
    v8::Local<v8::Value> args[] = {controller, jsChunk};
    v8::MaybeLocal<v8::Value> result = V8ScriptRunner::callExtra(
        scriptState, "ReadableStreamDefaultControllerEnqueue", args);
    result.ToLocalChecked();
  }

  template <typename ErrorType>
  void error(ErrorType error) {
    ScriptState* scriptState = m_scriptState.get();
    // This will assert that the context is valid; do not call this method when
    // the context is invalidated.
    ScriptState::Scope scope(scriptState);
    v8::Isolate* isolate = scriptState->isolate();

    v8::Local<v8::Value> controller = m_jsController.newLocal(isolate);
    if (controller.IsEmpty())
      return;

    v8::Local<v8::Value> jsError = toV8(error, scriptState);
    v8::Local<v8::Value> args[] = {controller, jsError};
    v8::MaybeLocal<v8::Value> result = V8ScriptRunner::callExtra(
        scriptState, "ReadableStreamDefaultControllerError", args);
    m_jsController.clear();
    result.ToLocalChecked();
  }

 private:
  RefPtr<ScriptState> m_scriptState;
  ScopedPersistent<v8::Value> m_jsController;
};

}  // namespace blink

#endif  // ReadableStreamController_h