// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
 
using Microsoft.VisualStudio.Text;
using Roslyn.Utilities;
 
namespace Microsoft.CodeAnalysis.Editor.Shared.Tagging;
 
internal partial class TaggerEventSources
{
    private class TextChangedEventSource : AbstractTaggerEventSource
    {
        private readonly ITextBuffer _subjectBuffer;
 
        public TextChangedEventSource(ITextBuffer subjectBuffer)
        {
            Contract.ThrowIfNull(subjectBuffer);
            _subjectBuffer = subjectBuffer;
        }
 
        public override void Connect()
            => _subjectBuffer.Changed += OnTextBufferChanged;
 
        public override void Disconnect()
            => _subjectBuffer.Changed -= OnTextBufferChanged;
 
        private void OnTextBufferChanged(object? sender, TextContentChangedEventArgs e)
        {
            if (e.Changes.Count == 0)
                return;
 
            this.RaiseChanged();
        }
    }
}