67 lines
1.9 KiB
C++
67 lines
1.9 KiB
C++
// Copyright The OpenTelemetry Authors
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// SPDX-License-Identifier: Apache-2.0
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#pragma once
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#include <cstdint>
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#include "opentelemetry/nostd/span.h"
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#include "opentelemetry/version.h"
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OPENTELEMETRY_BEGIN_NAMESPACE
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namespace trace
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{
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// TraceFlags represents options for a Trace. These options are propagated to all child Spans
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// and determine features such as whether a Span should be traced. TraceFlags
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// are implemented as a bitmask.
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class TraceFlags final
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{
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public:
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static constexpr uint8_t kIsSampled = 1;
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static constexpr uint8_t kIsRandom = 2;
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/**
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* Valid flags in W3C Trace Context version 1.
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* See https://www.w3.org/TR/trace-context-1/#trace-flags
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*/
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static constexpr uint8_t kAllW3CTraceContext1Flags = kIsSampled;
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/**
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* Valid flags in W3C Trace Context version 2.
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* See https://www.w3.org/TR/trace-context-1/#trace-flags
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*/
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static constexpr uint8_t kAllW3CTraceContext2Flags = kIsSampled | kIsRandom;
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TraceFlags() noexcept : rep_{0} {}
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explicit TraceFlags(uint8_t flags) noexcept : rep_(flags) {}
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bool IsSampled() const noexcept { return rep_ & kIsSampled; }
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bool IsRandom() const noexcept { return rep_ & kIsRandom; }
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// Populates the buffer with the lowercase base16 representation of the flags.
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void ToLowerBase16(nostd::span<char, 2> buffer) const noexcept
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{
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constexpr char kHex[] = "0123456789ABCDEF";
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buffer[0] = kHex[(rep_ >> 4) & 0xF];
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buffer[1] = kHex[(rep_ >> 0) & 0xF];
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}
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uint8_t flags() const noexcept { return rep_; }
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bool operator==(const TraceFlags &that) const noexcept { return rep_ == that.rep_; }
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bool operator!=(const TraceFlags &that) const noexcept { return !(*this == that); }
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// Copies the TraceFlags to dest.
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void CopyBytesTo(nostd::span<uint8_t, 1> dest) const noexcept { dest[0] = rep_; }
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private:
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uint8_t rep_;
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};
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} // namespace trace
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OPENTELEMETRY_END_NAMESPACE
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