electron/shell/browser/api/message_port.h

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// Copyright (c) 2020 Slack Technologies, Inc.
// Use of this source code is governed by the MIT license that can be
// found in the LICENSE file.
#ifndef SHELL_BROWSER_API_MESSAGE_PORT_H_
#define SHELL_BROWSER_API_MESSAGE_PORT_H_
#include <memory>
#include <vector>
#include "gin/wrappable.h"
#include "mojo/public/cpp/bindings/connector.h"
#include "mojo/public/cpp/bindings/message.h"
#include "third_party/blink/public/common/messaging/message_port_channel.h"
namespace gin {
class Arguments;
template <typename T>
class Handle;
} // namespace gin
namespace electron {
// A non-blink version of blink::MessagePort.
class MessagePort : public gin::Wrappable<MessagePort>, mojo::MessageReceiver {
public:
~MessagePort() override;
static gin::Handle<MessagePort> Create(v8::Isolate* isolate);
void PostMessage(gin::Arguments* args);
void Start();
void Close();
void Entangle(mojo::ScopedMessagePipeHandle handle);
void Entangle(blink::MessagePortChannel channel);
blink::MessagePortChannel Disentangle();
bool IsEntangled() const { return !closed_ && !IsNeutered(); }
bool IsNeutered() const { return !connector_ || !connector_->is_valid(); }
static std::vector<gin::Handle<MessagePort>> EntanglePorts(
v8::Isolate* isolate,
std::vector<blink::MessagePortChannel> channels);
static std::vector<blink::MessagePortChannel> DisentanglePorts(
v8::Isolate* isolate,
const std::vector<gin::Handle<MessagePort>>& ports,
bool* threw_exception);
// gin::Wrappable
gin::ObjectTemplateBuilder GetObjectTemplateBuilder(
v8::Isolate* isolate) override;
static gin::WrapperInfo kWrapperInfo;
const char* GetTypeName() override;
private:
MessagePort();
// The blink version of MessagePort uses the very nice "ActiveScriptWrapper"
// class, which keeps the object alive through the V8 embedder hooks into the
// GC lifecycle: see
// https://source.chromium.org/chromium/chromium/src/+/master:third_party/blink/renderer/platform/heap/thread_state.cc;l=258;drc=b892cf58e162a8f66cd76d7472f129fe0fb6a7d1
// We do not have that luxury, so we brutishly use v8::Global to accomplish
// something similar. Critically, whenever the value of
// "HasPendingActivity()" changes, we must call Pin() or Unpin() as
// appropriate.
bool HasPendingActivity() const;
void Pin();
void Unpin();
// mojo::MessageReceiver
bool Accept(mojo::Message* mojo_message) override;
std::unique_ptr<mojo::Connector> connector_;
bool started_ = false;
bool closed_ = false;
v8::Global<v8::Value> pinned_;
base::WeakPtrFactory<MessagePort> weak_factory_{this};
};
} // namespace electron
#endif // SHELL_BROWSER_API_MESSAGE_PORT_H_