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perf: Reduce exceptions of APIPage deserialization (#10548)
perf: reduce exceptions of APIPage deserialization
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‎src/Docfx.Build/OneOfJsonConverterFactory.cs

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@@ -2,9 +2,13 @@
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// The .NET Foundation licenses this file to you under the MIT license.
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using System.Diagnostics;
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using System.Diagnostics.CodeAnalysis;
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using System.Diagnostics.Contracts;
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using System.Reflection;
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using System.Runtime.CompilerServices;
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using System.Text.Json;
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using System.Text.Json.Serialization;
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using Docfx.Build.ApiPage;
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using OneOf;
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#nullable enable
@@ -38,6 +42,9 @@ private class OneOfJsonConverter<T> : JsonConverter<T> where T : IOneOf
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// It also depends on marking discriminator properties as required.
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foreach (var (type, cast) in s_types)
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{
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if (!IsDeserializableType(ref reader, type, typeToConvert))
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continue;
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try
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{
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Utf8JsonReader readerCopy = reader;
@@ -77,5 +84,177 @@ private static (Type type, MethodInfo cast)[] GetOneOfTypes()
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}
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throw new InvalidOperationException($"{typeof(T)} isn't OneOf or OneOfBase");
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}
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/// <summary>
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/// Helper method to check it can deserialize to specified type.
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/// </summary>
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/// <param name="reader">Current reader.</param>
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/// <param name="type">The type that to be deserialized by JsonSerializer.</param>
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/// <param name="typeToConvert">The type that to be converted by JsonConverter.</param>
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private static bool IsDeserializableType(ref Utf8JsonReader reader, Type type, Type typeToConvert)
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{
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var tokenType = reader.TokenType;
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switch (tokenType)
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{
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case JsonTokenType.String:
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if (type == typeof(bool) && typeToConvert == typeof(OneOf<bool, string>))
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return false;
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Assert(type, [typeof(string), typeof(Span)]);
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Assert(typeToConvert, [typeof(Span), typeof(Inline), typeof(OneOf<string, string[]>), typeof(OneOf<bool, string>)]);
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return true;
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case JsonTokenType.StartArray:
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Assert(type, [typeof(string), typeof(string[]), typeof(Span), typeof(Span[])]);
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Assert(typeToConvert, [typeof(Inline), typeof(OneOf<string, string[]>)]);
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return type.IsArray;
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case JsonTokenType.StartObject:
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if (!TryGetFirstPropertyName(ref reader, out var propertyName))
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return false;
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var key = (typeToConvert, type, propertyName);
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if (KnownTypes.Contains(key))
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return true;
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if (KnownTypesToSkip.Contains(key))
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return false;
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// Unknown type/name combinations found.
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// Fallback to default behavior.
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return true;
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default:
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return true;
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}
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}
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private static bool TryGetFirstPropertyName(ref Utf8JsonReader reader, [NotNullWhen(true)] out string? propertyName)
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{
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Contract.Assert(reader.TokenType == JsonTokenType.StartObject);
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var readerCopy = reader;
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if (readerCopy.Read() && readerCopy.TokenType == JsonTokenType.PropertyName)
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{
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propertyName = readerCopy.GetString()!;
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return true;
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}
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propertyName = null;
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return false;
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}
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[Conditional("DEBUG")]
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private static void Assert(
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Type type,
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Type[] expectedTypes,
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[CallerArgumentExpression(nameof(expectedTypes))] string? message = null)
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{
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if (!expectedTypes.Contains(type))
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throw new InvalidOperationException($"{type.Name} is not expected. Expected: {message}");
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}
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/// <summary>
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/// Known type/name combinations that can be deserialize.
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/// </summary>
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private static readonly HashSet<(Type, Type, string)> KnownTypes =
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[
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// Block : OneOfBase<Heading, Api, Markdown, Facts, Parameters, List, Inheritance, Code>
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(typeof(Block), typeof(Heading), "h1"),
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(typeof(Block), typeof(Heading), "h2"),
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(typeof(Block), typeof(Heading), "h3"),
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(typeof(Block), typeof(Heading), "h4"),
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(typeof(Block), typeof(Heading), "h5"),
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(typeof(Block), typeof(Heading), "h6"),
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(typeof(Block), typeof(Api), "api1"),
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(typeof(Block), typeof(Api), "api2"),
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(typeof(Block), typeof(Api), "api3"),
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(typeof(Block), typeof(Api), "api4"),
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(typeof(Block), typeof(Markdown), "markdown"),
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(typeof(Block), typeof(Facts), "facts"),
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(typeof(Block), typeof(Parameters), "parameters"),
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(typeof(Block), typeof(List), "list"),
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(typeof(Block), typeof(Inheritance), "inheritance"),
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(typeof(Block), typeof(Code), "code"),
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// Heading : OneOfBase<H1, H2, H3, H4, H5, H6>
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(typeof(Heading), typeof(H1), "h1"),
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(typeof(Heading), typeof(H2), "h2"),
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(typeof(Heading), typeof(H3), "h3"),
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(typeof(Heading), typeof(H4), "h4"),
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(typeof(Heading), typeof(H5), "h5"),
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(typeof(Heading), typeof(H6), "h6"),
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// Api : OneOfBase<Api1, Api2, Api3, Api4>
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(typeof(Api), typeof(Api1), "api1"),
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(typeof(Api), typeof(Api2), "api2"),
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(typeof(Api), typeof(Api3), "api3"),
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(typeof(Api), typeof(Api4), "api4"),
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// Span : OneOfBase<string, LinkSpan>
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(typeof(Span), typeof(LinkSpan), "text"),
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// Inline : OneOfBase<Span, Span[]>
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(typeof(Inline), typeof(Span), "text"),
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];
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/// <summary>
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/// Known type/name combinations that can not be deserialize.
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/// </summary>
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private static readonly HashSet<(Type, Type, string)> KnownTypesToSkip =
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[
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// Block : OneOfBase<Heading, Api, Markdown, Facts, Parameters, List, Inheritance, Code>
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(typeof(Heading), typeof(H1), "h2"),
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(typeof(Heading), typeof(H1), "h3"),
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(typeof(Heading), typeof(H2), "h3"),
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(typeof(Heading), typeof(H1), "h4"),
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(typeof(Heading), typeof(H2), "h4"),
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(typeof(Heading), typeof(H3), "h4"),
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(typeof(Block), typeof(Heading), "api1"),
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(typeof(Block), typeof(Heading), "api2"),
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(typeof(Block), typeof(Heading), "api3"),
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(typeof(Block), typeof(Heading), "api4"),
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(typeof(Block), typeof(Heading), "markdown"),
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(typeof(Block), typeof(Api), "markdown"),
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(typeof(Block), typeof(Heading), "facts"),
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(typeof(Block), typeof(Api), "facts"),
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(typeof(Block), typeof(Markdown), "facts"),
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(typeof(Block), typeof(Heading), "parameters"),
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(typeof(Block), typeof(Api), "parameters"),
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(typeof(Block), typeof(Markdown), "parameters"),
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(typeof(Block), typeof(Facts), "parameters"),
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(typeof(Block), typeof(Heading), "list"),
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(typeof(Block), typeof(Api), "list"),
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(typeof(Block), typeof(Markdown), "list"),
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(typeof(Block), typeof(Facts), "list"),
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(typeof(Block), typeof(Parameters), "list"),
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(typeof(Block), typeof(Heading), "inheritance"),
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(typeof(Block), typeof(Api), "inheritance"),
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(typeof(Block), typeof(Markdown), "inheritance"),
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(typeof(Block), typeof(Facts), "inheritance"),
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(typeof(Block), typeof(Parameters), "inheritance"),
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(typeof(Block), typeof(List), "inheritance"),
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(typeof(Block), typeof(Heading), "code"),
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(typeof(Block), typeof(Api), "code"),
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(typeof(Block), typeof(Markdown), "code"),
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(typeof(Block), typeof(Facts), "code"),
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(typeof(Block), typeof(Parameters), "code"),
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(typeof(Block), typeof(List), "code"),
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(typeof(Block), typeof(Inheritance), "code"),
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// OneOfBase<Api1, Api2, Api3, Api4>
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(typeof(Api), typeof(Api1), "api2"),
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(typeof(Api), typeof(Api1), "api3"),
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(typeof(Api), typeof(Api2), "api3"),
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(typeof(Api), typeof(Api1), "api4"),
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(typeof(Api), typeof(Api2), "api4"),
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(typeof(Api), typeof(Api3), "api4"),
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// OneOfBase<string, LinkSpan>
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(typeof(Span), typeof(String), "text"),
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];
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}
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}

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