using System;

namespace Umbraco.Cms.Core
{
    /// <summary>
    /// Provides an equivalent to the c# lock statement, to be used in a using block.
    /// </summary>
    /// <remarks>Ie replace <c>lock (o) {...}</c> by <c>using (new MonitorLock(o)) { ... }</c></remarks>
    public class MonitorLock : IDisposable
    {
        private readonly object _locker;
        private readonly bool _entered;

        /// <summary>
        /// Initializes a new instance of the <see cref="MonitorLock"/> class with an object to lock.
        /// </summary>
        /// <param name="locker">The object to lock.</param>
        /// <remarks>Should always be used within a using block.</remarks>
        public MonitorLock(object locker)
        {
            _locker = locker;
            _entered = false;
            System.Threading.Monitor.Enter(_locker, ref _entered);
        }

        void IDisposable.Dispose()
        {
            if (_entered)
                System.Threading.Monitor.Exit(_locker);
        }
    }
}
