Chromium Mojo(IPC)进程通信演示 c++（4）

122版本自带的mojom通信例子仅供学习参考：

codelabs\mojo_examples\01-multi-process

其余定义参考文章：

Chromium Mojo(IPC)进程通信演示 c++（2）-CSDN博客

01-mojo-browser.exe 与 01mojo-renderer.exe进程通信完整例子。

一、目录结构：

二、01-mojo-browser.exe

// Copyright 2023 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.#include "base/command_line.h"
#include "base/logging.h"
#include "base/process/launch.h"
#include "base/run_loop.h"
#include "codelabs/mojo_examples/mojom/interface.mojom.h"
#include "codelabs/mojo_examples/process_bootstrapper.h"
#include "mojo/public/cpp/bindings/associated_remote.h"
#include "mojo/public/cpp/bindings/pending_remote.h"
#include "mojo/public/cpp/bindings/remote.h"
#include "mojo/public/cpp/platform/platform_channel.h"
#include "mojo/public/cpp/system/invitation.h"
#include "mojo/public/cpp/system/message_pipe.h"mojo::ScopedMessagePipeHandle LaunchAndConnect() {// Under the hood, this is essentially always an OS pipe (domain socket pair,// Windows named pipe, Fuchsia channel, etc).mojo::PlatformChannel channel;mojo::OutgoingInvitation invitation;// Attach a message pipe to be extracted by the receiver. The other end of the// pipe is returned for us to use locally. We choose the arbitrary name "pipe"// here, which is the same name that the receiver will have to use when// plucking this pipe off of the invitation it receives to join our process// network.mojo::ScopedMessagePipeHandle pipe = invitation.AttachMessagePipe("pipe");base::LaunchOptions options;// This is the relative path to the mock "renderer process" binary. We pass it// into `base::LaunchProcess` to run the binary in a new process.static const base::CommandLine::CharType* argv[] = {FILE_PATH_LITERAL("./01-mojo-renderer")};base::CommandLine command_line(1, argv);// Delegating to Mojo to "prepare" the command line will append the// `--mojo-platform-channel-handle=N` command line argument, so that the// renderer knows which file descriptor name to recover, in order to establish// the primordial connection with this process. We log the full command line// next, to show what mojo information the renderer will be initiated with.channel.PrepareToPassRemoteEndpoint(&options, &command_line);LOG(INFO) << "Browser: " << command_line.GetCommandLineString();base::Process child_process = base::LaunchProcess(command_line, options);channel.RemoteProcessLaunchAttempted();mojo::OutgoingInvitation::Send(std::move(invitation), child_process.Handle(),channel.TakeLocalEndpoint());return pipe;
}void CreateProcessRemote(mojo::ScopedMessagePipeHandle pipe) {mojo::PendingRemote<codelabs::mojom::Process> pending_remote(std::move(pipe),0u);mojo::Remote<codelabs::mojom::Process> remote(std::move(pending_remote));LOG(INFO) << "Browser invoking SayHello() on remote pointing to renderer";remote->SayHello();
}int main(int argc, char** argv) {LOG(INFO) << "'Browser process' starting up";base::CommandLine::Init(argc, argv);ProcessBootstrapper bootstrapper;bootstrapper.InitMainThread(base::MessagePumpType::IO);bootstrapper.InitMojo(/*as_browser_process=*/true);mojo::ScopedMessagePipeHandle pipe = LaunchAndConnect();base::SequencedTaskRunner::GetCurrentDefault()->PostTask(FROM_HERE, base::BindOnce(&CreateProcessRemote, std::move(pipe)));base::RunLoop run_loop;// Delay shutdown of the browser process for visual effects, as well as to// ensure the browser process doesn't die while the IPC message is still being// sent to the target process asynchronously, which would prevent its// delivery.base::SequencedTaskRunner::GetCurrentDefault()->PostDelayedTask(FROM_HERE,base::BindOnce([](base::OnceClosure quit_closure) {LOG(INFO) << "'Browser process' shutting down";std::move(quit_closure).Run();},run_loop.QuitClosure()),base::Seconds(2));run_loop.Run();return 0;
}

三、01-mojo-renderer.exe

// Copyright 2023 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.#include "base/command_line.h"
#include "base/logging.h"
#include "base/run_loop.h"
#include "codelabs/mojo_examples/mojom/interface.mojom.h"
#include "codelabs/mojo_examples/process_bootstrapper.h"
#include "mojo/public/cpp/bindings/associated_receiver.h"
#include "mojo/public/cpp/bindings/pending_receiver.h"
#include "mojo/public/cpp/bindings/receiver.h"
#include "mojo/public/cpp/platform/platform_channel.h"
#include "mojo/public/cpp/system/invitation.h"
#include "mojo/public/cpp/system/message_pipe.h"class ProcessImpl : public codelabs::mojom::Process {public:explicit ProcessImpl(mojo::PendingReceiver<codelabs::mojom::Process> pending_receiver) {receiver_.Bind(std::move(pending_receiver));}private:// codelabs::mojo::Processvoid GetAssociatedInterface(const std::string&,mojo::PendingAssociatedReceiver<codelabs::mojom::GenericInterface>)override {NOTREACHED();}void SayHello() override { LOG(INFO) << "Hello!"; }mojo::Receiver<codelabs::mojom::Process> receiver_{this};
};
ProcessImpl* g_process_impl = nullptr;void BindProcessImpl(mojo::ScopedMessagePipeHandle pipe) {// Create a receivermojo::PendingReceiver<codelabs::mojom::Process> pending_receiver(std::move(pipe));g_process_impl = new ProcessImpl(std::move(pending_receiver));
}int main(int argc, char** argv) {base::CommandLine::Init(argc, argv);// Logging the entire command line shows all of the information that the// browser seeded the renderer with. Notably, this includes the mojo platform// channel handle that the renderer will use to bootstrap its primordial// connection with the browser process.LOG(INFO) << "Renderer: "<< base::CommandLine::ForCurrentProcess()->GetCommandLineString();ProcessBootstrapper bootstrapper;bootstrapper.InitMainThread(base::MessagePumpType::IO);bootstrapper.InitMojo(/*as_browser_process=*/false);// Accept an invitation.//// `RecoverPassedEndpointFromCommandLine()` is what makes use of the mojo// platform channel handle that gets printed in the above `LOG()`; this is the// file descriptor of the first connection that this process shares with the// browser.mojo::IncomingInvitation invitation = mojo::IncomingInvitation::Accept(mojo::PlatformChannel::RecoverPassedEndpointFromCommandLine(*base::CommandLine::ForCurrentProcess()));// Extract one end of the first pipe by the name that the browser process// added this pipe to the invitation by.mojo::ScopedMessagePipeHandle pipe = invitation.ExtractMessagePipe("pipe");base::RunLoop run_loop;base::SequencedTaskRunner::GetCurrentDefault()->PostTask(FROM_HERE, base::BindOnce(&BindProcessImpl, std::move(pipe)));run_loop.Run();return 0;
}