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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.
using System.Linq;
using Microsoft.AspNetCore.Mvc.Rendering;
using Microsoft.AspNetCore.Mvc.ViewFeatures;
using Microsoft.AspNetCore.Razor.TagHelpers;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
namespace Microsoft.AspNetCore.Mvc.Razor.TagHelpers;
/// <summary>
/// Initializes and processes the <see cref="ITagHelperComponent"/>s added to the
/// <see cref="ITagHelperComponentManager.Components"/> in the specified order.
/// </summary>
public abstract partial class TagHelperComponentTagHelper : TagHelper
{
private readonly ILogger _logger;
private readonly ITagHelperComponent[] _components;
/// <summary>
/// Creates a new <see cref="TagHelperComponentTagHelper"/> and orders the
/// the collection of <see cref="ITagHelperComponent"/>s in <see cref="ITagHelperComponentManager.Components"/>.
/// </summary>
/// <param name="manager">The <see cref="ITagHelperComponentManager"/> which contains the collection
/// of <see cref="ITagHelperComponent"/>s.</param>
/// <param name="loggerFactory">The <see cref="ILoggerFactory"/>.</param>
/// <remarks>The <see cref="ITagHelperComponentManager.Components"/> are ordered after the
/// creation of the <see cref="ITagHelperComponentManager"/> to position the <see cref="ITagHelperComponent"/>s
/// added from controllers and views correctly.</remarks>
public TagHelperComponentTagHelper(
ITagHelperComponentManager manager,
ILoggerFactory loggerFactory)
{
ArgumentNullException.ThrowIfNull(manager);
ArgumentNullException.ThrowIfNull(loggerFactory);
_components = manager.Components.OrderBy(p => p.Order).ToArray();
_logger = loggerFactory.CreateLogger(GetType());
}
/// <summary>
/// Activates the <see cref="ViewContext"/> property of all the <see cref="ITagHelperComponentManager.Components"/>.
/// </summary>
[HtmlAttributeNotBound]
public ITagHelperComponentPropertyActivator PropertyActivator { get; set; } = default!;
/// <summary>
/// The <see cref="ViewContext"/>.
/// </summary>
[ViewContext]
[HtmlAttributeNotBound]
public ViewContext ViewContext { get; set; } = default!;
/// <inheritdoc />
public override void Init(TagHelperContext context)
{
if (PropertyActivator == null)
{
var serviceProvider = ViewContext.HttpContext.RequestServices;
PropertyActivator = serviceProvider.GetRequiredService<ITagHelperComponentPropertyActivator>();
}
for (var i = 0; i < _components.Length; i++)
{
var component = _components[i];
PropertyActivator.Activate(ViewContext, component);
component.Init(context);
if (_logger.IsEnabled(LogLevel.Debug))
{
Log.TagHelperComponentInitialized(_logger, component.GetType().FullName!);
}
}
}
/// <inheritdoc />
public override async Task ProcessAsync(TagHelperContext context, TagHelperOutput output)
{
for (var i = 0; i < _components.Length; i++)
{
var component = _components[i];
await component.ProcessAsync(context, output);
if (_logger.IsEnabled(LogLevel.Debug))
{
Log.TagHelperComponentProcessed(_logger, component.GetType().FullName!);
}
}
}
private static partial class Log
{
[LoggerMessage(2, LogLevel.Debug, "Tag helper component '{ComponentName}' initialized.", EventName = "TagHelperComponentInitialized", SkipEnabledCheck = true)]
public static partial void TagHelperComponentInitialized(ILogger logger, string componentName);
[LoggerMessage(3, LogLevel.Debug, "Tag helper component '{ComponentName}' processed.", EventName = "TagHelperComponentProcessed", SkipEnabledCheck = true)]
public static partial void TagHelperComponentProcessed(ILogger logger, string componentName);
}
}
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