src/modular/benchmarks/tracing_waiter.cc

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

#include "src/modular/benchmarks/tracing_waiter.h"

#include <lib/async/default.h>

namespace modular {

TracingWaiter::TracingWaiter() = default;
TracingWaiter::~TracingWaiter() = default;

void TracingWaiter::WaitForTracing(fit::function<void()> cont) {
  // Cf. RunWithTracing() used by ledger benchmarks.
  trace_provider_ = std::make_unique<trace::TraceProviderWithFdio>(async_get_default_dispatcher());
  trace_observer_ = std::make_unique<trace::TraceObserver>();

  fit::function<void()> on_trace_state_changed = [this, cont = std::move(cont)] {
    if (TRACE_CATEGORY_ENABLED("benchmark") && !started_) {
      started_ = true;
      cont();
    }
  };

  // In case tracing has already started.
  on_trace_state_changed();

  if (!started_) {
    trace_observer_->Start(async_get_default_dispatcher(), std::move(on_trace_state_changed));
  }
}

}  // namespace modular