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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
namespace Microsoft.AspNetCore.Mvc.Abstractions;
/// <summary>
/// Defines an interface for components that can create an <see cref="IActionInvoker"/> for the
/// current request.
/// </summary>
/// <remarks>
/// <para>
/// <see cref="IActionInvokerProvider"/> instances form a pipeline that results in the creation of an
/// <see cref="IActionInvoker"/>. The <see cref="IActionInvokerProvider"/> instances are ordered by
/// an ascending sort of the <see cref="Order"/>.
/// </para>
/// <para>
/// To create an <see cref="IActionInvoker"/>, each provider has its <see cref="OnProvidersExecuting"/> method
/// called in sequence and given the same instance of <see cref="ActionInvokerProviderContext"/>. Then each
/// provider has its <see cref="OnProvidersExecuted"/> method called in the reverse order. The result is
/// the value of <see cref="ActionInvokerProviderContext.Result"/>.
/// </para>
/// <para>
/// As providers are called in a predefined sequence, each provider has a chance to observe and decorate the
/// result of the providers that have already run.
/// </para>
/// </remarks>
public interface IActionInvokerProvider
{
/// <summary>
/// Gets the order value for determining the order of execution of providers. Providers execute in
/// ascending numeric value of the <see cref="Order"/> property.
/// </summary>
/// <remarks>
/// <para>
/// Providers are executed in an ordering determined by an ascending sort of the <see cref="Order"/> property.
/// A provider with a lower numeric value of <see cref="Order"/> will have its
/// <see cref="OnProvidersExecuting"/> called before that of a provider with a higher numeric value of
/// <see cref="Order"/>. The <see cref="OnProvidersExecuted"/> method is called in the reverse ordering after
/// all calls to <see cref="OnProvidersExecuting"/>. A provider with a lower numeric value of
/// <see cref="Order"/> will have its <see cref="OnProvidersExecuted"/> method called after that of a provider
/// with a higher numeric value of <see cref="Order"/>.
/// </para>
/// <para>
/// If two providers have the same numeric value of <see cref="Order"/>, then their relative execution order
/// is undefined.
/// </para>
/// </remarks>
int Order { get; }
/// <summary>
/// Called to execute the provider.
/// </summary>
/// <param name="context">The <see cref="ActionInvokerProviderContext"/>.</param>
void OnProvidersExecuting(ActionInvokerProviderContext context);
/// <summary>
/// Called to execute the provider, after the <see cref="OnProvidersExecuting"/> methods of all providers,
/// have been called.
/// </summary>
/// <param name="context">The <see cref="ActionInvokerProviderContext"/>.</param>
void OnProvidersExecuted(ActionInvokerProviderContext context);
}
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