ceph/src/jaegertracing/opentelemetry-cpp/api/include/opentelemetry/trace/span_context_kv_iterable.h

   1 // Copyright The OpenTelemetry Authors
   2 // SPDX-License-Identifier: Apache-2.0
   3
   4 #pragma once
   5
   6 #include "opentelemetry/common/attribute_value.h"
   7 #include "opentelemetry/common/key_value_iterable_view.h"
   8 #include "opentelemetry/nostd/function_ref.h"
   9 #include "opentelemetry/version.h"
  10
  11 OPENTELEMETRY_BEGIN_NAMESPACE
  12 namespace trace
  13 {
  14 /**
  15  * Supports internal iteration over a collection of SpanContext/key-value pairs.
  16  */
  17 class SpanContextKeyValueIterable
  18 {
  19 public:
  20   virtual ~SpanContextKeyValueIterable() = default;
  21
  22   /**
  23    * Iterate over SpanContext/key-value pairs
  24    * @param callback a callback to invoke for each key-value for each SpanContext.
  25    * If the callback returns false, the iteration is aborted.
  26    * @return true if every SpanContext/key-value pair was iterated over
  27    */
  28   virtual bool ForEachKeyValue(
  29       nostd::function_ref<bool(SpanContext, const opentelemetry::common::KeyValueIterable &)>
  30           callback) const noexcept = 0;
  31   /**
  32    * @return the number of key-value pairs
  33    */
  34   virtual size_t size() const noexcept = 0;
  35 };
  36
  37 /**
  38  * @brief Null Span context that does not carry any information.
  39  */
  40 class NullSpanContext : public SpanContextKeyValueIterable
  41 {
  42 public:
  43   bool ForEachKeyValue(
  44       nostd::function_ref<bool(SpanContext, const opentelemetry::common::KeyValueIterable &)>
  45       /* callback */) const noexcept override
  46   {
  47     return true;
  48   }
  49
  50   size_t size() const noexcept override { return 0; };
  51 };
  52
  53 }  // namespace trace
  54 OPENTELEMETRY_END_NAMESPACE