chromium/components/cast/message_port/blink_message_port_adapter.cc

// Copyright 2021 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "components/cast/message_port/blink_message_port_adapter.h"

#include <string_view>

#include "base/functional/callback.h"
#include "base/memory/raw_ptr.h"
#include "components/cast/message_port/cast/message_port_cast.h"
#include "components/cast/message_port/platform_message_port.h"

namespace cast_api_bindings {
namespace {

// MessagePortAdapters are used to adapt between two different implementations
// of cast_api_bindings::MessagePort.
//
// PostMessageWithTransferables flow including adaptation:
//+---+     +-------+    +---------+        +---------+   +-------+   +---+
//| A |     | PortA |    | AdptrA  |        | AdptrB  |   | PortB |   | B |
//+---+     +-------+    +---------+        +---------+   +-------+   +---+
//  | Post      |             |                  |            |         |
//  |---------->|             |                  |            |         |
//  |           | OnMsg       |                  |            |         |
//  |           |------------>|                  |            |         |
//  |           |             | Adapt Ports      |            |         |
//  |           |             |-----------|      |            |         |
//  |           |             |<----------|      |            |         |
//  |           |             | Post             |            |         |
//  |           |             |----------------->|            |         |
//  |           |             |                  | OnMsg      |         |
//  |           |             |                  |----------->|         |
//  |           |             |                  |            | OnMsg   |
//  |           |             |                  |            |-------->|
//
// Error flow including deletion, for example when OnMessage fails
//  |           |             |                  |            |   false |
//  |           |             |                  |            |<--------|
//  |           |             |                  |      OnErr |         |
//  |           |             |                  |<-----------|         |
//  |           |             |           delete |            |         |
//  |           |             |<-----------------|            |         |
//  |           |      delete |                  |            |         |
//  |           |<------------|                  |            |         |
//  |     OnErr |             |                  |            |         |
//  |<----------|             |                  |            |         |
//  |           |             |                  | delete     |         |
//  |           |             |                  |------|     |         |
//  |           |             |                  |<-----|     |         |
class MessagePortAdapter : public MessagePort::Receiver { … };
}  // namespace

// static
std::unique_ptr<MessagePort>
BlinkMessagePortAdapter::ToClientPlatformMessagePort(
    blink::WebMessagePort&& client) { … }

// static
blink::WebMessagePort BlinkMessagePortAdapter::FromServerPlatformMessagePort(
    std::unique_ptr<MessagePort> server) { … }
}  // namespace cast_api_bindings