1 files changed, 54 insertions, 0 deletions
diff --git a/src/jaegertracing/opentelemetry-cpp/api/include/opentelemetry/trace/span_context_kv_iterable.h b/src/jaegertracing/opentelemetry-cpp/api/include/opentelemetry/trace/span_context_kv_iterable.h
new file mode 100644
index 000000000..2cbff8d65
--- /dev/null
+++ b/src/jaegertracing/opentelemetry-cpp/api/include/opentelemetry/trace/span_context_kv_iterable.h
@@ -0,0 +1,54 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+
+#include "opentelemetry/common/attribute_value.h"
+#include "opentelemetry/common/key_value_iterable_view.h"
+#include "opentelemetry/nostd/function_ref.h"
+#include "opentelemetry/version.h"
+
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace trace
+{
+/**
+ * Supports internal iteration over a collection of SpanContext/key-value pairs.
+ */
+class SpanContextKeyValueIterable
+{
+public:
+  virtual ~SpanContextKeyValueIterable() = default;
+
+  /**
+   * Iterate over SpanContext/key-value pairs
+   * @param callback a callback to invoke for each key-value for each SpanContext.
+   * If the callback returns false, the iteration is aborted.
+   * @return true if every SpanContext/key-value pair was iterated over
+   */
+  virtual bool ForEachKeyValue(
+      nostd::function_ref<bool(SpanContext, const opentelemetry::common::KeyValueIterable &)>
+          callback) const noexcept = 0;
+  /**
+   * @return the number of key-value pairs
+   */
+  virtual size_t size() const noexcept = 0;
+};
+
+/**
+ * @brief Null Span context that does not carry any information.
+ */
+class NullSpanContext : public SpanContextKeyValueIterable
+{
+public:
+  bool ForEachKeyValue(
+      nostd::function_ref<bool(SpanContext, const opentelemetry::common::KeyValueIterable &)>
+      /* callback */) const noexcept override
+  {
+    return true;
+  }
+
+  size_t size() const noexcept override { return 0; };
+};
+
+}  // namespace trace
+OPENTELEMETRY_END_NAMESPACE