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// Copyright 2019 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CONTENT_BROWSER_TRACING_TRACING_SERVICE_CONTROLLER_H_
#define CONTENT_BROWSER_TRACING_TRACING_SERVICE_CONTROLLER_H_
#include <map>
#include <memory>
#include "base/functional/callback.h"
#include "base/no_destructor.h"
#include "base/process/process_handle.h"
#include "base/types/pass_key.h"
#include "mojo/public/cpp/bindings/pending_receiver.h"
#include "mojo/public/cpp/bindings/remote.h"
#include "services/tracing/public/mojom/traced_process.mojom.h"
#include "services/tracing/public/mojom/tracing_service.mojom.h"
namespace content {
// Processes participating in tracing must register themselves with the global
// instance of this object.
class TracingServiceController {
public:
// An object held for the duration of any client process's registration with
// the tracing service.
class ClientRegistration {
public:
ClientRegistration(base::PassKey<TracingServiceController>,
base::OnceClosure unregister);
~ClientRegistration();
private:
base::OnceClosure unregister_;
};
TracingServiceController(const TracingServiceController&) = delete;
~TracingServiceController();
TracingServiceController& operator=(const TracingServiceController&) = delete;
// Gets the global instance of this object. Safe to call from any sequence,
// but see individual methods for other potential constraints.
static TracingServiceController& Get();
// A callback each process host must provide to implement how a TracedProcess
// interface is bound in the corresponding client process. Callbacks are
// always called from the UI thread.
using EnableTracingCallback = base::RepeatingCallback<void(
mojo::PendingReceiver<tracing::mojom::TracedProcess>)>;
// Registers a new client process with the tracing system. Any time the
// tracing service is started, |callback| will be invoked to connect the
// client process to the service.
//
// The process will remain registered as long as the returned
// ClientRegistration object remains alive.
//
// Safe to call from any sequence.
std::unique_ptr<ClientRegistration> RegisterClient(
base::ProcessId pid,
EnableTracingCallback callback);
// Retrieves a remote interface to the tracing service, which is started
// lazily if needed. Public content API consumers can use
// |content::GetTracingService()|.
//
// Must only be called on the UI thread.
tracing::mojom::TracingService& GetService();
private:
friend class base::NoDestructor<TracingServiceController>;
TracingServiceController();
// Handles disconnection by the tracing service.
void OnTracingServiceDisconnected();
void RegisterClientOnUIThread(base::ProcessId pid,
EnableTracingCallback callback);
void RemoveClient(base::ProcessId pid);
// NOTE: This state is accessed only from the UI thread.
mojo::Remote<tracing::mojom::TracingService> service_;
std::map<base::ProcessId, EnableTracingCallback> clients_;
};
} // namespace content
#endif // CONTENT_BROWSER_TRACING_TRACING_SERVICE_CONTROLLER_H_
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