src/tracing/ipc/consumer/consumer_ipc_client_impl.cc - third_party/perfetto - Git at Google

 /*
  * Copyright (C) 2017 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #include "src/tracing/ipc/consumer/consumer_ipc_client_impl.h"

 #include <inttypes.h>
 #include <string.h>

 #include "perfetto/base/task_runner.h"
 #include "perfetto/ext/ipc/client.h"
 #include "perfetto/ext/tracing/core/consumer.h"
 #include "perfetto/ext/tracing/core/observable_events.h"
 #include "perfetto/ext/tracing/core/trace_stats.h"
 #include "perfetto/tracing/core/trace_config.h"
 #include "perfetto/tracing/core/tracing_service_state.h"

 // TODO(fmayer): Add a test to check to what happens when ConsumerIPCClientImpl
 // gets destroyed w.r.t. the Consumer pointer. Also think to lifetime of the
 // Consumer* during the callbacks.

 namespace perfetto {

 // static. (Declared in include/tracing/ipc/consumer_ipc_client.h).
 std::unique_ptr<TracingService::ConsumerEndpoint> ConsumerIPCClient::Connect(
     const char* service_sock_name,
     Consumer* consumer,
     base::TaskRunner* task_runner) {
   return std::unique_ptr<TracingService::ConsumerEndpoint>(
       new ConsumerIPCClientImpl(service_sock_name, consumer, task_runner));
 }

 ConsumerIPCClientImpl::ConsumerIPCClientImpl(const char* service_sock_name,
                                              Consumer* consumer,
                                              base::TaskRunner* task_runner)
     : consumer_(consumer),
       ipc_channel_(ipc::Client::CreateInstance(service_sock_name, task_runner)),
       consumer_port_(this /* event_listener */),
       weak_ptr_factory_(this) {
   ipc_channel_->BindService(consumer_port_.GetWeakPtr());
 }

 ConsumerIPCClientImpl::~ConsumerIPCClientImpl() = default;

 // Called by the IPC layer if the BindService() succeeds.
 void ConsumerIPCClientImpl::OnConnect() {
   connected_ = true;
   consumer_->OnConnect();
 }

 void ConsumerIPCClientImpl::OnDisconnect() {
   PERFETTO_DLOG("Tracing service connection failure");
   connected_ = false;
   consumer_->OnDisconnect();
 }

 void ConsumerIPCClientImpl::EnableTracing(const TraceConfig& trace_config,
                                           base::ScopedFile fd) {
   if (!connected_) {
     PERFETTO_DLOG("Cannot EnableTracing(), not connected to tracing service");
     return;
   }

   protos::EnableTracingRequest req;
   trace_config.ToProto(req.mutable_trace_config());
   ipc::Deferred<protos::EnableTracingResponse> async_response;
   auto weak_this = weak_ptr_factory_.GetWeakPtr();
   async_response.Bind(
       [weak_this](ipc::AsyncResult<protos::EnableTracingResponse> response) {
         if (weak_this)
           weak_this->OnEnableTracingResponse(std::move(response));
       });

   // |fd| will be closed when this function returns, but it's fine because the
   // IPC layer dup()'s it when sending the IPC.
   consumer_port_.EnableTracing(req, std::move(async_response), *fd);
 }

 void ConsumerIPCClientImpl::ChangeTraceConfig(const TraceConfig&) {
   if (!connected_) {
     PERFETTO_DLOG(
         "Cannot ChangeTraceConfig(), not connected to tracing service");
     return;
   }

   ipc::Deferred<protos::ChangeTraceConfigResponse> async_response;
   async_response.Bind(
       [](ipc::AsyncResult<protos::ChangeTraceConfigResponse> response) {
         if (!response)
           PERFETTO_DLOG("ChangeTraceConfig() failed");
       });
   protos::ChangeTraceConfigRequest req;
   consumer_port_.ChangeTraceConfig(req, std::move(async_response));
 }

 void ConsumerIPCClientImpl::StartTracing() {
   if (!connected_) {
     PERFETTO_DLOG("Cannot StartTracing(), not connected to tracing service");
     return;
   }

   ipc::Deferred<protos::StartTracingResponse> async_response;
   async_response.Bind(
       [](ipc::AsyncResult<protos::StartTracingResponse> response) {
         if (!response)
           PERFETTO_DLOG("StartTracing() failed");
       });
   protos::StartTracingRequest req;
   consumer_port_.StartTracing(req, std::move(async_response));
 }

 void ConsumerIPCClientImpl::DisableTracing() {
   if (!connected_) {
     PERFETTO_DLOG("Cannot DisableTracing(), not connected to tracing service");
     return;
   }

   ipc::Deferred<protos::DisableTracingResponse> async_response;
   async_response.Bind(
       [](ipc::AsyncResult<protos::DisableTracingResponse> response) {
         if (!response)
           PERFETTO_DLOG("DisableTracing() failed");
       });
   consumer_port_.DisableTracing(protos::DisableTracingRequest(),
                                 std::move(async_response));
 }

 void ConsumerIPCClientImpl::ReadBuffers() {
   if (!connected_) {
     PERFETTO_DLOG("Cannot ReadBuffers(), not connected to tracing service");
     return;
   }

   ipc::Deferred<protos::ReadBuffersResponse> async_response;

   // The IPC layer guarantees that callbacks are destroyed after this object
   // is destroyed (by virtue of destroying the |consumer_port_|). In turn the
   // contract of this class expects the caller to not destroy the Consumer class
   // before having destroyed this class. Hence binding |this| here is safe.
   async_response.Bind(
       [this](ipc::AsyncResult<protos::ReadBuffersResponse> response) {
         OnReadBuffersResponse(std::move(response));
       });
   consumer_port_.ReadBuffers(protos::ReadBuffersRequest(),
                              std::move(async_response));
 }

 void ConsumerIPCClientImpl::OnReadBuffersResponse(
     ipc::AsyncResult<protos::ReadBuffersResponse> response) {
   if (!response) {
     PERFETTO_DLOG("ReadBuffers() failed");
     return;
   }
   std::vector<TracePacket> trace_packets;
   for (auto& resp_slice : response->slices()) {
     const std::string& slice_data = resp_slice.data();
     Slice slice = Slice::Allocate(slice_data.size());
     memcpy(slice.own_data(), slice_data.data(), slice.size);
     partial_packet_.AddSlice(std::move(slice));
     if (resp_slice.last_slice_for_packet())
       trace_packets.emplace_back(std::move(partial_packet_));
   }
   if (!trace_packets.empty() || !response.has_more())
     consumer_->OnTraceData(std::move(trace_packets), response.has_more());
 }

 void ConsumerIPCClientImpl::OnEnableTracingResponse(
     ipc::AsyncResult<protos::EnableTracingResponse> response) {
   if (!response || response->disabled())
     consumer_->OnTracingDisabled();
 }

 void ConsumerIPCClientImpl::FreeBuffers() {
   if (!connected_) {
     PERFETTO_DLOG("Cannot FreeBuffers(), not connected to tracing service");
     return;
   }

   protos::FreeBuffersRequest req;
   ipc::Deferred<protos::FreeBuffersResponse> async_response;
   async_response.Bind(
       [](ipc::AsyncResult<protos::FreeBuffersResponse> response) {
         if (!response)
           PERFETTO_DLOG("FreeBuffers() failed");
       });
   consumer_port_.FreeBuffers(req, std::move(async_response));
 }

 void ConsumerIPCClientImpl::Flush(uint32_t timeout_ms, FlushCallback callback) {
   if (!connected_) {
     PERFETTO_DLOG("Cannot Flush(), not connected to tracing service");
     return callback(/*success=*/false);
   }

   protos::FlushRequest req;
   req.set_timeout_ms(static_cast<uint32_t>(timeout_ms));
   ipc::Deferred<protos::FlushResponse> async_response;
   async_response.Bind(
       [callback](ipc::AsyncResult<protos::FlushResponse> response) {
         callback(!!response);
       });
   consumer_port_.Flush(req, std::move(async_response));
 }

 void ConsumerIPCClientImpl::Detach(const std::string& key) {
   if (!connected_) {
     PERFETTO_DLOG("Cannot Detach(), not connected to tracing service");
     return;
   }

   protos::DetachRequest req;
   req.set_key(key);
   ipc::Deferred<protos::DetachResponse> async_response;
   auto weak_this = weak_ptr_factory_.GetWeakPtr();

   async_response.Bind(
       [weak_this](ipc::AsyncResult<protos::DetachResponse> response) {
         if (weak_this)
           weak_this->consumer_->OnDetach(!!response);
       });
   consumer_port_.Detach(req, std::move(async_response));
 }

 void ConsumerIPCClientImpl::Attach(const std::string& key) {
   if (!connected_) {
     PERFETTO_DLOG("Cannot Attach(), not connected to tracing service");
     return;
   }

   {
     protos::AttachRequest req;
     req.set_key(key);
     ipc::Deferred<protos::AttachResponse> async_response;
     auto weak_this = weak_ptr_factory_.GetWeakPtr();

     async_response.Bind([weak_this](
                             ipc::AsyncResult<protos::AttachResponse> response) {
       if (!weak_this)
         return;
       TraceConfig trace_config;
       if (!response) {
         weak_this->consumer_->OnAttach(/*success=*/false, trace_config);
         return;
       }
       trace_config.FromProto(response->trace_config());

       // If attached succesfully, also attach to the end-of-trace
       // notificaton callback, via EnableTracing(attach_notification_only).
       protos::EnableTracingRequest enable_req;
       enable_req.set_attach_notification_only(true);
       ipc::Deferred<protos::EnableTracingResponse> enable_resp;
       enable_resp.Bind(
           [weak_this](ipc::AsyncResult<protos::EnableTracingResponse> resp) {
             if (weak_this)
               weak_this->OnEnableTracingResponse(std::move(resp));
           });
       weak_this->consumer_port_.EnableTracing(enable_req,
                                               std::move(enable_resp));

       weak_this->consumer_->OnAttach(/*success=*/true, trace_config);
     });
     consumer_port_.Attach(req, std::move(async_response));
   }
 }

 void ConsumerIPCClientImpl::GetTraceStats() {
   if (!connected_) {
     PERFETTO_DLOG("Cannot GetTraceStats(), not connected to tracing service");
     return;
   }

   protos::GetTraceStatsRequest req;
   ipc::Deferred<protos::GetTraceStatsResponse> async_response;

   // The IPC layer guarantees that callbacks are destroyed after this object
   // is destroyed (by virtue of destroying the |consumer_port_|). In turn the
   // contract of this class expects the caller to not destroy the Consumer class
   // before having destroyed this class. Hence binding |this| here is safe.
   async_response.Bind(
       [this](ipc::AsyncResult<protos::GetTraceStatsResponse> response) {
         TraceStats trace_stats;
         if (!response) {
           consumer_->OnTraceStats(/*success=*/false, trace_stats);
           return;
         }
         trace_stats.FromProto(response->trace_stats());
         consumer_->OnTraceStats(/*success=*/true, trace_stats);
       });
   consumer_port_.GetTraceStats(req, std::move(async_response));
 }

 void ConsumerIPCClientImpl::ObserveEvents(uint32_t enabled_event_types) {
   if (!connected_) {
     PERFETTO_DLOG("Cannot ObserveEvents(), not connected to tracing service");
     return;
   }

   protos::ObserveEventsRequest req;
   if (enabled_event_types & ObservableEventType::kDataSourceInstances) {
     req.add_events_to_observe(
         protos::ObservableEvents::TYPE_DATA_SOURCES_INSTANCES);
   }
   ipc::Deferred<protos::ObserveEventsResponse> async_response;
   // The IPC layer guarantees that callbacks are destroyed after this object
   // is destroyed (by virtue of destroying the |consumer_port_|). In turn the
   // contract of this class expects the caller to not destroy the Consumer class
   // before having destroyed this class. Hence binding |this| here is safe.
   async_response.Bind(
       [this](ipc::AsyncResult<protos::ObserveEventsResponse> response) {
         // Skip empty response, which the service sends to close the stream.
         if (!response->events().instance_state_changes().size()) {
           PERFETTO_DCHECK(!response.has_more());
           return;
         }
         ObservableEvents events;
         events.FromProto(response->events());
         consumer_->OnObservableEvents(events);
       });
   consumer_port_.ObserveEvents(req, std::move(async_response));
 }

 void ConsumerIPCClientImpl::QueryServiceState(
     QueryServiceStateCallback callback) {
   if (!connected_) {
     PERFETTO_DLOG(
         "Cannot QueryServiceState(), not connected to tracing service");
     return;
   }

   protos::QueryServiceStateRequest req;
   ipc::Deferred<protos::QueryServiceStateResponse> async_response;
   async_response.Bind(
       [callback](ipc::AsyncResult<protos::QueryServiceStateResponse> response) {
         if (!response)
           callback(false, TracingServiceState());
         TracingServiceState svc_state;
         svc_state.FromProto(response->service_state());
         callback(true, svc_state);
       });
   consumer_port_.QueryServiceState(req, std::move(async_response));
 }

 }  // namespace perfetto
	/*
	* Copyright (C) 2017 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include "src/tracing/ipc/consumer/consumer_ipc_client_impl.h"

	#include <inttypes.h>
	#include <string.h>

	#include "perfetto/base/task_runner.h"
	#include "perfetto/ext/ipc/client.h"
	#include "perfetto/ext/tracing/core/consumer.h"
	#include "perfetto/ext/tracing/core/observable_events.h"
	#include "perfetto/ext/tracing/core/trace_stats.h"
	#include "perfetto/tracing/core/trace_config.h"
	#include "perfetto/tracing/core/tracing_service_state.h"

	// TODO(fmayer): Add a test to check to what happens when ConsumerIPCClientImpl
	// gets destroyed w.r.t. the Consumer pointer. Also think to lifetime of the
	// Consumer* during the callbacks.

	namespace perfetto {

	// static. (Declared in include/tracing/ipc/consumer_ipc_client.h).
	std::unique_ptr<TracingService::ConsumerEndpoint> ConsumerIPCClient::Connect(
	const char* service_sock_name,
	Consumer* consumer,
	base::TaskRunner* task_runner) {
	return std::unique_ptr<TracingService::ConsumerEndpoint>(
	new ConsumerIPCClientImpl(service_sock_name, consumer, task_runner));
	}

	ConsumerIPCClientImpl::ConsumerIPCClientImpl(const char* service_sock_name,
	Consumer* consumer,
	base::TaskRunner* task_runner)
	: consumer_(consumer),
	ipc_channel_(ipc::Client::CreateInstance(service_sock_name, task_runner)),
	consumer_port_(this /* event_listener */),
	weak_ptr_factory_(this) {
	ipc_channel_->BindService(consumer_port_.GetWeakPtr());
	}

	ConsumerIPCClientImpl::~ConsumerIPCClientImpl() = default;

	// Called by the IPC layer if the BindService() succeeds.
	void ConsumerIPCClientImpl::OnConnect() {
	connected_ = true;
	consumer_->OnConnect();
	}

	void ConsumerIPCClientImpl::OnDisconnect() {
	PERFETTO_DLOG("Tracing service connection failure");
	connected_ = false;
	consumer_->OnDisconnect();
	}

	void ConsumerIPCClientImpl::EnableTracing(const TraceConfig& trace_config,
	base::ScopedFile fd) {
	if (!connected_) {
	PERFETTO_DLOG("Cannot EnableTracing(), not connected to tracing service");
	return;
	}

	protos::EnableTracingRequest req;
	trace_config.ToProto(req.mutable_trace_config());
	ipc::Deferred<protos::EnableTracingResponse> async_response;
	auto weak_this = weak_ptr_factory_.GetWeakPtr();
	async_response.Bind(
	[weak_this](ipc::AsyncResult<protos::EnableTracingResponse> response) {
	if (weak_this)
	weak_this->OnEnableTracingResponse(std::move(response));
	});

	// \|fd\| will be closed when this function returns, but it's fine because the
	// IPC layer dup()'s it when sending the IPC.
	consumer_port_.EnableTracing(req, std::move(async_response), *fd);
	}

	void ConsumerIPCClientImpl::ChangeTraceConfig(const TraceConfig&) {
	if (!connected_) {
	PERFETTO_DLOG(
	"Cannot ChangeTraceConfig(), not connected to tracing service");
	return;
	}

	ipc::Deferred<protos::ChangeTraceConfigResponse> async_response;
	async_response.Bind(
	[](ipc::AsyncResult<protos::ChangeTraceConfigResponse> response) {
	if (!response)
	PERFETTO_DLOG("ChangeTraceConfig() failed");
	});
	protos::ChangeTraceConfigRequest req;
	consumer_port_.ChangeTraceConfig(req, std::move(async_response));
	}

	void ConsumerIPCClientImpl::StartTracing() {
	if (!connected_) {
	PERFETTO_DLOG("Cannot StartTracing(), not connected to tracing service");
	return;
	}

	ipc::Deferred<protos::StartTracingResponse> async_response;
	async_response.Bind(
	[](ipc::AsyncResult<protos::StartTracingResponse> response) {
	if (!response)
	PERFETTO_DLOG("StartTracing() failed");
	});
	protos::StartTracingRequest req;
	consumer_port_.StartTracing(req, std::move(async_response));
	}

	void ConsumerIPCClientImpl::DisableTracing() {
	if (!connected_) {
	PERFETTO_DLOG("Cannot DisableTracing(), not connected to tracing service");
	return;
	}

	ipc::Deferred<protos::DisableTracingResponse> async_response;
	async_response.Bind(
	[](ipc::AsyncResult<protos::DisableTracingResponse> response) {
	if (!response)
	PERFETTO_DLOG("DisableTracing() failed");
	});
	consumer_port_.DisableTracing(protos::DisableTracingRequest(),
	std::move(async_response));
	}

	void ConsumerIPCClientImpl::ReadBuffers() {
	if (!connected_) {
	PERFETTO_DLOG("Cannot ReadBuffers(), not connected to tracing service");
	return;
	}

	ipc::Deferred<protos::ReadBuffersResponse> async_response;

	// The IPC layer guarantees that callbacks are destroyed after this object
	// is destroyed (by virtue of destroying the \|consumer_port_\|). In turn the
	// contract of this class expects the caller to not destroy the Consumer class
	// before having destroyed this class. Hence binding \|this\| here is safe.
	async_response.Bind(
	[this](ipc::AsyncResult<protos::ReadBuffersResponse> response) {
	OnReadBuffersResponse(std::move(response));
	});
	consumer_port_.ReadBuffers(protos::ReadBuffersRequest(),
	std::move(async_response));
	}

	void ConsumerIPCClientImpl::OnReadBuffersResponse(
	ipc::AsyncResult<protos::ReadBuffersResponse> response) {
	if (!response) {
	PERFETTO_DLOG("ReadBuffers() failed");
	return;
	}
	std::vector<TracePacket> trace_packets;
	for (auto& resp_slice : response->slices()) {
	const std::string& slice_data = resp_slice.data();
	Slice slice = Slice::Allocate(slice_data.size());
	memcpy(slice.own_data(), slice_data.data(), slice.size);
	partial_packet_.AddSlice(std::move(slice));
	if (resp_slice.last_slice_for_packet())
	trace_packets.emplace_back(std::move(partial_packet_));
	}
	if (!trace_packets.empty() \|\| !response.has_more())
	consumer_->OnTraceData(std::move(trace_packets), response.has_more());
	}

	void ConsumerIPCClientImpl::OnEnableTracingResponse(
	ipc::AsyncResult<protos::EnableTracingResponse> response) {
	if (!response \|\| response->disabled())
	consumer_->OnTracingDisabled();
	}

	void ConsumerIPCClientImpl::FreeBuffers() {
	if (!connected_) {
	PERFETTO_DLOG("Cannot FreeBuffers(), not connected to tracing service");
	return;
	}

	protos::FreeBuffersRequest req;
	ipc::Deferred<protos::FreeBuffersResponse> async_response;
	async_response.Bind(
	[](ipc::AsyncResult<protos::FreeBuffersResponse> response) {
	if (!response)
	PERFETTO_DLOG("FreeBuffers() failed");
	});
	consumer_port_.FreeBuffers(req, std::move(async_response));
	}

	void ConsumerIPCClientImpl::Flush(uint32_t timeout_ms, FlushCallback callback) {
	if (!connected_) {
	PERFETTO_DLOG("Cannot Flush(), not connected to tracing service");
	return callback(/success=/false);
	}

	protos::FlushRequest req;
	req.set_timeout_ms(static_cast<uint32_t>(timeout_ms));
	ipc::Deferred<protos::FlushResponse> async_response;
	async_response.Bind(
	[callback](ipc::AsyncResult<protos::FlushResponse> response) {
	callback(!!response);
	});
	consumer_port_.Flush(req, std::move(async_response));
	}

	void ConsumerIPCClientImpl::Detach(const std::string& key) {
	if (!connected_) {
	PERFETTO_DLOG("Cannot Detach(), not connected to tracing service");
	return;
	}

	protos::DetachRequest req;
	req.set_key(key);
	ipc::Deferred<protos::DetachResponse> async_response;
	auto weak_this = weak_ptr_factory_.GetWeakPtr();

	async_response.Bind(
	[weak_this](ipc::AsyncResult<protos::DetachResponse> response) {
	if (weak_this)
	weak_this->consumer_->OnDetach(!!response);
	});
	consumer_port_.Detach(req, std::move(async_response));
	}

	void ConsumerIPCClientImpl::Attach(const std::string& key) {
	if (!connected_) {
	PERFETTO_DLOG("Cannot Attach(), not connected to tracing service");
	return;
	}

	{
	protos::AttachRequest req;
	req.set_key(key);
	ipc::Deferred<protos::AttachResponse> async_response;
	auto weak_this = weak_ptr_factory_.GetWeakPtr();

	async_response.Bind([weak_this](
	ipc::AsyncResult<protos::AttachResponse> response) {
	if (!weak_this)
	return;
	TraceConfig trace_config;
	if (!response) {
	weak_this->consumer_->OnAttach(/success=/false, trace_config);
	return;
	}
	trace_config.FromProto(response->trace_config());

	// If attached succesfully, also attach to the end-of-trace
	// notificaton callback, via EnableTracing(attach_notification_only).
	protos::EnableTracingRequest enable_req;
	enable_req.set_attach_notification_only(true);
	ipc::Deferred<protos::EnableTracingResponse> enable_resp;
	enable_resp.Bind(
	[weak_this](ipc::AsyncResult<protos::EnableTracingResponse> resp) {
	if (weak_this)
	weak_this->OnEnableTracingResponse(std::move(resp));
	});
	weak_this->consumer_port_.EnableTracing(enable_req,
	std::move(enable_resp));

	weak_this->consumer_->OnAttach(/success=/true, trace_config);
	});
	consumer_port_.Attach(req, std::move(async_response));
	}
	}

	void ConsumerIPCClientImpl::GetTraceStats() {
	if (!connected_) {
	PERFETTO_DLOG("Cannot GetTraceStats(), not connected to tracing service");
	return;
	}

	protos::GetTraceStatsRequest req;
	ipc::Deferred<protos::GetTraceStatsResponse> async_response;

	// The IPC layer guarantees that callbacks are destroyed after this object
	// is destroyed (by virtue of destroying the \|consumer_port_\|). In turn the
	// contract of this class expects the caller to not destroy the Consumer class
	// before having destroyed this class. Hence binding \|this\| here is safe.
	async_response.Bind(
	[this](ipc::AsyncResult<protos::GetTraceStatsResponse> response) {
	TraceStats trace_stats;
	if (!response) {
	consumer_->OnTraceStats(/success=/false, trace_stats);
	return;
	}
	trace_stats.FromProto(response->trace_stats());
	consumer_->OnTraceStats(/success=/true, trace_stats);
	});
	consumer_port_.GetTraceStats(req, std::move(async_response));
	}

	void ConsumerIPCClientImpl::ObserveEvents(uint32_t enabled_event_types) {
	if (!connected_) {
	PERFETTO_DLOG("Cannot ObserveEvents(), not connected to tracing service");
	return;
	}

	protos::ObserveEventsRequest req;
	if (enabled_event_types & ObservableEventType::kDataSourceInstances) {
	req.add_events_to_observe(
	protos::ObservableEvents::TYPE_DATA_SOURCES_INSTANCES);
	}
	ipc::Deferred<protos::ObserveEventsResponse> async_response;
	// The IPC layer guarantees that callbacks are destroyed after this object
	// is destroyed (by virtue of destroying the \|consumer_port_\|). In turn the
	// contract of this class expects the caller to not destroy the Consumer class
	// before having destroyed this class. Hence binding \|this\| here is safe.
	async_response.Bind(
	[this](ipc::AsyncResult<protos::ObserveEventsResponse> response) {
	// Skip empty response, which the service sends to close the stream.
	if (!response->events().instance_state_changes().size()) {
	PERFETTO_DCHECK(!response.has_more());
	return;
	}
	ObservableEvents events;
	events.FromProto(response->events());
	consumer_->OnObservableEvents(events);
	});
	consumer_port_.ObserveEvents(req, std::move(async_response));
	}

	void ConsumerIPCClientImpl::QueryServiceState(
	QueryServiceStateCallback callback) {
	if (!connected_) {
	PERFETTO_DLOG(
	"Cannot QueryServiceState(), not connected to tracing service");
	return;
	}

	protos::QueryServiceStateRequest req;
	ipc::Deferred<protos::QueryServiceStateResponse> async_response;
	async_response.Bind(
	[callback](ipc::AsyncResult<protos::QueryServiceStateResponse> response) {
	if (!response)
	callback(false, TracingServiceState());
	TracingServiceState svc_state;
	svc_state.FromProto(response->service_state());
	callback(true, svc_state);
	});
	consumer_port_.QueryServiceState(req, std::move(async_response));
	}

	} // namespace perfetto