Line data    Source code

       1             : #pragma once
       2             : 
       3             : // This component provides an interface, `DictReader`, that represents a
       4             : // read-only key/value mapping of strings.  It's used when extracting trace
       5             : // context from externalized formats: HTTP headers, gRPC metadata, etc.
       6             : 
       7             : #include <functional>
       8             : 
       9             : #include "optional.h"
      10             : #include "string_view.h"
      11             : 
      12             : namespace datadog {
      13             : namespace tracing {
      14             : 
      15             : class DictReader {
      16             :  public:
      17         637 :   virtual ~DictReader() {}
      18             : 
      19             :   // Return the value at the specified `key`, or return `nullopt` if there
      20             :   // is no value at `key`.
      21             :   virtual Optional<StringView> lookup(StringView key) const = 0;
      22             : 
      23             :   // Invoke the specified `visitor` once for each key/value pair in this object.
      24             :   virtual void visit(
      25             :       const std::function<void(StringView key, StringView value)>& visitor)
      26             :       const = 0;
      27             : };
      28             : 
      29             : }  // namespace tracing
      30             : }  // namespace datadog