one_time_message_handler.h | Explore in Territory

// Copyright 2017 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef EXTENSIONS_RENDERER_API_MESSAGING_ONE_TIME_MESSAGE_HANDLER_H_
#define EXTENSIONS_RENDERER_API_MESSAGING_ONE_TIME_MESSAGE_HANDLER_H_

#include <stdint.h>

#include <memory>
#include <optional>
#include <string>

#include "base/memory/raw_ptr.h"
#include "base/memory/weak_ptr.h"
#include "extensions/common/mojom/message_port.mojom.h"
#include "extensions/renderer/bindings/api_binding_types.h"
#include "v8/include/v8-forward.h"

namespace base {
class Value;
}

namespace gin {
class Arguments;
}

namespace extensions {

namespace mojom {
enum class ChannelType;
}

class NativeExtensionBindingsSystem;
class ScriptContext;
struct Message;
struct MessageTarget;
struct PortId;

// A class for handling one-time message communication, including
// runtime.sendMessage and extension.sendRequest. These methods use the same
// underlying architecture as long-lived port-based communications (like
// runtime.connect), but are exposed through a simpler API.
// A basic flow will be from an "opener" (the original sender) and a "receiver"
// (the event listener), which will be in two separate contexts (and potentially
// renderer processes). The flow is outlined below:
//
// chrome.runtime.sendMessage(  // initiates the sendMessage flow, triggering
//                              // SendMessage().
//     {foo: bar},              // The data sent with SendMessage().
//     function() { ... });     // The response callback in SendMessage().
//
// This creates a new opener port in the context, and posts a message to it
// with the data. The browser then dispatches this to other renderers.
//
// In another context, we have:
// chrome.runtime.onMessage.addListener(function(message, sender, reply) {
//   ...
//   reply(...);
// });
//
// When the renderer receives the connection message, we will create a
// new receiver port in this context via AddReceiver().
// When the message comes in, we reply with DeliverMessage() to the receiver's
// port ID.
// If the receiver replies via the reply callback, it will send a new message
// back along the port to the browser. The browser then sends this message back
// to the opener's renderer, where it is delivered via DeliverMessage().
//
// This concludes the one-time message flow.
class OneTimeMessageHandler { … };

}  // namespace extensions

#endif  // EXTENSIONS_RENDERER_API_MESSAGING_ONE_TIME_MESSAGE_HANDLER_H_
chromium/extensions/renderer/api/messaging/one_time_message_handler.h
