// Copyright 2017, OpenCensus Authors

//

// 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 OPENCENSUS_TRACE_TRACE_OPTIONS_H_

#define OPENCENSUS_TRACE_TRACE_OPTIONS_H_

#include <cstdint>

#include <string>

namespace opencensus {

namespace trace {

class SpanGenerator;

class SpanTestPeer;

// TraceOptions represents the options for a trace. These options are propagated

// to all child spans within the given trace. Currently only the IsSampled

// option is supported. TraceOptions is thread-compatible.

class TraceOptions final {

 public:

  // The size in bytes of the TraceOptions.

  static constexpr size_t kSize = 1;

  // No options are enabled by default.

  TraceOptions() : rep_{0} {}

  // Creates TraceOptions from a buffer of exactly kSize bytes.

  explicit TraceOptions(const uint8_t* buf);

  // IsSampled means that the trace should be sampled for exporting outside of

  // the process, e.g. to Stackdriver/Zipkin.

  bool IsSampled() const;

  bool operator==(const TraceOptions& that) const;

  // Returns a 2-char hex string of the TraceOptions value.

  std::string ToHex() const;

  // Copies the TraceOptions data to a buffer, which must hold kSize bytes.

  void CopyTo(uint8_t* buf) const;

  // Returns a copy of these TraceOptions with the sampled bit set to

  // is_sampled.

  TraceOptions WithSampling(bool is_sampled) const;

 private:

  uint8_t rep_[kSize];

};

}  // namespace trace

}  // namespace opencensus

#endif  // OPENCENSUS_TRACE_TRACE_OPTIONS_H_