LegacyPropagator.cs

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using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Net;
 
namespace System.Diagnostics;
 
internal sealed class LegacyPropagator : DistributedContextPropagator
{
    internal static DistributedContextPropagator Instance { get; } = new LegacyPropagator();
 
 
    public override IReadOnlyCollection<string> Fields { get; } = new ReadOnlyCollection<string>(new string[5] { "traceparent", "Request-Id", "tracestate", "baggage", "Correlation-Context" });
 
 
    public override void Inject(Activity activity, object carrier, PropagatorSetterCallback setter)
    {
        if (activity == null || setter == null)
        {
            return;
        }
        string id = activity.Id;
        if (id == null)
        {
            return;
        }
        if (activity.IdFormat == ActivityIdFormat.W3C)
        {
            setter(carrier, "traceparent", id);
            if (!string.IsNullOrEmpty(activity.TraceStateString))
            {
                setter(carrier, "tracestate", activity.TraceStateString);
            }
        }
        else
        {
            setter(carrier, "Request-Id", id);
        }
        DistributedContextPropagator.InjectBaggage(carrier, activity.Baggage, setter);
    }
 
    public override void ExtractTraceIdAndState(object carrier, PropagatorGetterCallback getter, out string traceId, out string traceState)
    {
        if (getter == null)
        {
            traceId = null;
            traceState = null;
            return;
        }
        getter(carrier, "traceparent", out traceId, out var fieldValues);
        if (traceId == null)
        {
            getter(carrier, "Request-Id", out traceId, out fieldValues);
        }
        getter(carrier, "tracestate", out traceState, out fieldValues);
    }
 
    public override IEnumerable<KeyValuePair<string, string>> ExtractBaggage(object carrier, PropagatorGetterCallback getter)
    {
        if (getter == null)
        {
            return null;
        }
        getter(carrier, "baggage", out var fieldValue, out var fieldValues);
        IEnumerable<KeyValuePair<string, string>> baggage = null;
        if (fieldValue == null || !TryExtractBaggage(fieldValue, out baggage))
        {
            getter(carrier, "Correlation-Context", out fieldValue, out fieldValues);
            if (fieldValue != null)
            {
                TryExtractBaggage(fieldValue, out baggage);
            }
        }
        return baggage;
    }
 
    internal static bool TryExtractBaggage(string baggageString, out IEnumerable<KeyValuePair<string, string>> baggage)
    {
        baggage = null;
        List<KeyValuePair<string, string>> list = null;
        if (string.IsNullOrEmpty(baggageString))
        {
            return true;
        }
        int i = 0;
        while (true)
        {
            if (i < baggageString.Length && (baggageString[i] == ' ' || baggageString[i] == '\t'))
            {
                i++;
                continue;
            }
            if (i >= baggageString.Length)
            {
                break;
            }
            int num = i;
            for (; i < baggageString.Length && baggageString[i] != ' ' && baggageString[i] != '\t' && baggageString[i] != '='; i++)
            {
            }
            if (i >= baggageString.Length)
            {
                break;
            }
            int num2 = i;
            if (baggageString[i] != '=')
            {
                for (; i < baggageString.Length && (baggageString[i] == ' ' || baggageString[i] == '\t'); i++)
                {
                }
                if (i >= baggageString.Length || baggageString[i] != '=')
                {
                    break;
                }
            }
            for (i++; i < baggageString.Length && (baggageString[i] == ' ' || baggageString[i] == '\t'); i++)
            {
            }
            if (i >= baggageString.Length)
            {
                break;
            }
            int num3 = i;
            for (; i < baggageString.Length && baggageString[i] != ' ' && baggageString[i] != '\t' && baggageString[i] != ',' && baggageString[i] != ';'; i++)
            {
            }
            if (num < num2 && num3 < i)
            {
                if (list == null)
                {
                    list = new List<KeyValuePair<string, string>>();
                }
                list.Insert(0, new KeyValuePair<string, string>(WebUtility.UrlDecode(baggageString.Substring(num, num2 - num)).Trim(DistributedContextPropagator.s_trimmingSpaceCharacters), WebUtility.UrlDecode(baggageString.Substring(num3, i - num3)).Trim(DistributedContextPropagator.s_trimmingSpaceCharacters)));
            }
            for (; i < baggageString.Length && baggageString[i] != ','; i++)
            {
            }
            i++;
            if (i >= baggageString.Length)
            {
                break;
            }
        }
        baggage = list;
        return list != null;
    }
}