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// 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, mach port, 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.
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("./02-mojo-renderer")};
base::CommandLine command_line(1, argv);
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) {
// An unassociated remote to the toy "renderer" process. We us this to bind
// two associated interface requests.
mojo::PendingRemote<codelabs::mojom::Process> pending_remote(std::move(pipe),
/*version=*/0u);
mojo::Remote<codelabs::mojom::Process> remote(std::move(pending_remote));
remote->SayHello();
// Make an associated interface request for ObjectA and send an IPC.
mojo::PendingAssociatedRemote<codelabs::mojom::GenericInterface>
pending_generic;
remote->GetAssociatedInterface(
"ObjectA", pending_generic.InitWithNewEndpointAndPassReceiver());
mojo::PendingAssociatedRemote<codelabs::mojom::ObjectA> pending_a(
pending_generic.PassHandle(), /*version=*/0u);
mojo::AssociatedRemote<codelabs::mojom::ObjectA> remote_a(
std::move(pending_a));
LOG(INFO) << "Calling ObjectA::DoA() from the browser";
remote_a->DoA();
// Do the same for ObjectB.
mojo::PendingAssociatedRemote<codelabs::mojom::GenericInterface>
pending_generic_2;
remote->GetAssociatedInterface(
"ObjectB", pending_generic_2.InitWithNewEndpointAndPassReceiver());
mojo::PendingAssociatedRemote<codelabs::mojom::ObjectB> pending_b(
pending_generic_2.PassHandle(), /*version=*/0u);
mojo::AssociatedRemote<codelabs::mojom::ObjectB> remote_b(
std::move(pending_b));
LOG(INFO) << "Calling ObjectB::DoB() from the browser";
remote_b->DoB();
}
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. This delay is an arbitrary 5 seconds, which just needs to be
// longer than the renderer's 3 seconds, which is used to show visually via
// logging, how the ordering of IPCs can be effected by a frozen task queue
// that gets unfrozen 3 seconds later.
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(5));
run_loop.Run();
return 0;
}
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