tracing/scoped_span.cc

// Copyright 2026 Google LLC
//
// 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
//
//    https://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 "tracing/scoped_span.h"

#include <memory>
#include <utility>

#include "tracing/span.h"
#include "tracing/thread_context.h"

namespace credentio_tracing {

ScopedSpan::ScopedSpan(Span* span)
    : span_(span), previous_span_(ThreadContext::GetCurrentSpan()) {
  if (span_) {
    ThreadContext::SetCurrentSpan(span_);
  }
}

ScopedSpan::ScopedSpan(std::unique_ptr<Span> span)
    : owned_span_(std::move(span)),
      span_(owned_span_.get()),
      previous_span_(ThreadContext::GetCurrentSpan()) {
  if (span_) {
    ThreadContext::SetCurrentSpan(span_);
  }
}

void ScopedSpan::Teardown() {
  if (active_) {
    if (owned_span_) {
      owned_span_->End();
    }
    ThreadContext::SetCurrentSpan(previous_span_);
    active_ = false;
  }
}

ScopedSpan::~ScopedSpan() { Teardown(); }

ScopedSpan::ScopedSpan(ScopedSpan&& other) noexcept
    : owned_span_(std::move(other.owned_span_)),
      span_(std::exchange(other.span_, nullptr)),
      previous_span_(std::exchange(other.previous_span_, nullptr)),
      active_(std::exchange(other.active_, false)) {
  // NOMUTANTS -- Defensive cleanup; previous_span_ is private and only accessed
  // when active_ is true.
}

ScopedSpan& ScopedSpan::operator=(ScopedSpan&& other) noexcept {
  if (this != &other) {
    Teardown();
    owned_span_ = std::move(other.owned_span_);
    span_ = std::exchange(other.span_, nullptr);
    // NOMUTANTS -- Defensive cleanup; previous_span_ is private and only
    // accessed when active_ is true.
    previous_span_ = std::exchange(other.previous_span_, nullptr);
    active_ = std::exchange(other.active_, false);
    if (active_ && span_) {
      ThreadContext::SetCurrentSpan(span_);
    }
  }
  return *this;
}

}  // namespace credentio_tracing