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/*
* Copyright (C) 2019 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.
*/
#ifndef INCLUDE_PERFETTO_TRACING_INTERNAL_TRACING_MUXER_H_
#define INCLUDE_PERFETTO_TRACING_INTERNAL_TRACING_MUXER_H_
#include <atomic>
#include <memory>
#include "perfetto/base/export.h"
#include "perfetto/tracing/core/forward_decls.h"
#include "perfetto/tracing/interceptor.h"
#include "perfetto/tracing/internal/basic_types.h"
#include "perfetto/tracing/internal/tracing_tls.h"
#include "perfetto/tracing/platform.h"
namespace perfetto {
class DataSourceBase;
class TraceWriterBase;
struct TracingInitArgs;
class TracingSession;
namespace internal {
struct DataSourceStaticState;
// This class acts as a bridge between the public API methods and the
// TracingBackend(s). It exposes a simplified view of the world to the API
// methods, so that they don't have to care about the multiplicity of backends.
// It handles all the bookkeeping to map data source instances and trace writers
// to the various backends.
// See tracing_muxer_impl.h for the full picture. This class contains only the
// fewer fields and methods that need to be exposed to public/ headers. Fields
// and methods that are required to implement them should go into
// src/tracing/internal/tracing_muxer_impl.h instead: that one can pull in
// perfetto headers outside of public, this one cannot.
class PERFETTO_EXPORT TracingMuxer {
public:
static TracingMuxer* Get() { return instance_; }
virtual ~TracingMuxer();
TracingTLS* GetOrCreateTracingTLS() {
return static_cast<TracingTLS*>(platform_->GetOrCreateThreadLocalObject());
}
// This method can fail and return false if trying to register more than
// kMaxDataSources types.
using DataSourceFactory = std::function<std::unique_ptr<DataSourceBase>()>;
virtual bool RegisterDataSource(const DataSourceDescriptor&,
DataSourceFactory,
DataSourceStaticState*) = 0;
// Updates the DataSourceDescriptor for the DataSource.
virtual void UpdateDataSourceDescriptor(const DataSourceDescriptor&,
const DataSourceStaticState*) = 0;
// It identifies the right backend and forwards the call to it.
// The returned TraceWriter must be used within the same sequence (for most
// projects this means "same thread"). Alternatively the client needs to take
// care of using synchronization primitives to prevent concurrent accesses.
virtual std::unique_ptr<TraceWriterBase> CreateTraceWriter(
DataSourceStaticState*,
uint32_t data_source_instance_index,
DataSourceState*,
BufferExhaustedPolicy buffer_exhausted_policy) = 0;
virtual void DestroyStoppedTraceWritersForCurrentThread() = 0;
uint32_t generation(std::memory_order ord) { return generation_.load(ord); }
using InterceptorFactory = std::function<std::unique_ptr<InterceptorBase>()>;
virtual void RegisterInterceptor(const InterceptorDescriptor&,
InterceptorFactory,
InterceptorBase::TLSFactory,
InterceptorBase::TracePacketCallback) = 0;
// Informs the tracing services to activate any of these triggers if any
// tracing session was waiting for them.
//
// Sends the trigger signal to all the initialized backends that are currently
// connected and that connect in the next `ttl_ms` milliseconds (but returns
// immediately anyway).
virtual void ActivateTriggers(const std::vector<std::string>&,
uint32_t ttl_ms) = 0;
protected:
explicit TracingMuxer(Platform* platform) : platform_(platform) {}
static TracingMuxer* instance_;
Platform* const platform_ = nullptr;
// Incremented every time a data source is destroyed. See tracing_tls.h.
std::atomic<uint32_t> generation_{};
};
} // namespace internal
} // namespace perfetto
#endif // INCLUDE_PERFETTO_TRACING_INTERNAL_TRACING_MUXER_H_
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