63 lines
2 KiB
C#
63 lines
2 KiB
C#
using System;
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using System.Collections.Generic;
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using System.Linq;
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using Gallium;
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namespace Nitride.Contents;
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/// <summary>
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/// Various extension methods for working with content.
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/// </summary>
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public static class EntityContentExtensions
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{
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/// <summary>
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/// Retrieves the single registered content entity inside the component.
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/// If there is more than one, this will throw an exception.
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/// </summary>
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/// <param name="entity">The entity to query.</param>
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/// <returns>The one and only content component.</returns>
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public static IContent GetContent(this Entity entity)
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{
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Type type = entity.GetComponentTypes()
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.Single(x => typeof(IContent).IsAssignableFrom(x));
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return entity.Get<IContent>(type);
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}
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/// <summary>
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/// Determines if the entity has at least one content component.
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/// </summary>
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/// <param name="entity">The entity to inspect.</param>
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/// <returns>True if there is a component extending `IContent`.</returns>
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public static bool HasContent(this Entity entity)
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{
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return entity.GetComponentTypes()
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.Any(x => typeof(IContent).IsAssignableFrom(x));
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}
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/// <summary>
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/// Remove all existing content components from the entity and then adds
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/// the new component into the entity before returning it.
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/// </summary>
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/// <param name="entity">The entity to query and modify.</param>
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/// <param name="content">The content to add to the entity.</param>
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/// <typeparam name="TType">The base type of the content.</typeparam>
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/// <returns>The entity or a copy with the new component.</returns>
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public static Entity SetContent<TType>(
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this Entity entity,
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TType content)
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where TType : IContent
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{
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IEnumerable<Type>? existing = entity.GetComponentTypes()
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.Where(x => typeof(IContent).IsAssignableFrom(x));
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foreach (Type? component in existing)
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{
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entity = entity.Remove(component);
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}
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return entity.Add(content);
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}
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}
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