ProjectArcade

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using System.Runtime.InteropServices;
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namespace DokanNet
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{
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    internal static class NativeStructWrapper
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    {
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        public static NativeStructWrapper<T> Wrap<T>(T obj) where T : class
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        {
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            return new NativeStructWrapper<T>(obj);
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        }
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    }
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    /// <summary>
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    /// This class allocates unmanaged memory for a native structure and initializes
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    /// that memory by marshalling a managed object. It gurantees that the managed
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    /// object stays alive and the unmanaged memory block is valid for at least the
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    /// lifetime of this object and that the unmanaged memory is released when this
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    /// object is disposed.
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    /// 
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    /// Since this class derives form SafeBuffer there are many instance methods
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    /// available to read and modify the unmanaged buffer in a safe way and when
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    /// marshalled to native code in for example a P/Invoke call, it gets automatically
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    /// translated to the address of the unmanaged memory block. It also uses reference
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    /// counting and is guaranteed to stay alive during such calls.
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    /// <see cref="SafeBuffer"/>
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    /// </summary>
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    /// <typeparam name="T">Type of managed object</typeparam>
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    internal class NativeStructWrapper<T> : SafeBuffer where T : class
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    {
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        /// <summary>
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        /// Initializes a new instance by allocating unmanaged memory and marshalling
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        /// the supplied managed object to that memory.
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        /// </summary>
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        /// <param name="obj">Managed object to marshal to unmanaged memory</param>
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        public NativeStructWrapper(T obj) : base(ownsHandle: true)
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        {
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            var size = Marshal.SizeOf(obj);
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            SetHandle(Marshal.AllocHGlobal(size));
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            Initialize((ulong)size);
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            Object = obj;
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            Marshal.StructureToPtr(obj, handle, false);
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        }
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        /// <summary>
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        /// Initializes an empty instance. Used internally by native marshaller and
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        /// not intended to be used directly from user code.
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        /// </summary>
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        internal NativeStructWrapper() : base(ownsHandle: true) { }
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        /// <summary>
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        /// Managed object that was originally marshalled to unmanaged memory.
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        /// </summary>
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        public T Object { get; private set; }
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        /// <summary>
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        /// Releases unmanaged memory used by this instance.
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        /// </summary>
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        /// <returns>Always returns true</returns>
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        protected override bool ReleaseHandle()
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        {
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            Marshal.FreeHGlobal(handle);
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            return true;
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        }
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    }
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}
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