ComObject.cs

// Copyright (c) 2010-2014 SharpDX - Alexandre Mutel
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

using System;
using System.Reflection;
using System.Runtime.InteropServices;

namespace SharpGen.Runtime
{
    /// <summary>
    /// Root IUnknown class to interop with COM object
    /// </summary>
    public partial class ComObject
    {
        /// <summary>
        /// Initializes a new instance of the <see cref="ComObject"/> class from a IUnknown object.
        /// </summary>
        /// <param name="iunknownObject">Reference to a IUnknown object</param>
        public ComObject(object iunknownObject)
        {
            NativePointer = Marshal.GetIUnknownForObject(iunknownObject);
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="ComObject"/> class.
        /// </summary>
        protected ComObject()
        {
        }

        /// <summary>
        ///   Query instance for a particular COM GUID/interface support.
        /// </summary>
        /// <param name = "guid">GUID query interface</param>
        /// <exception cref="SharpGenException">If this object doesn't support the interface</exception>
        /// <msdn-id>ms682521</msdn-id>
        /// <unmanaged>IUnknown::QueryInterface</unmanaged>	
        /// <unmanaged-short>IUnknown::QueryInterface</unmanaged-short>
        public virtual IntPtr QueryInterfaceOrNull(Guid guid)
        {
            var pointer = IntPtr.Zero;
            QueryInterface(guid, out pointer);
            return pointer;
        }

        /// <summary>
        /// Compares 2 COM objects and return true if the native pointer is the same.
        /// </summary>
        /// <param name="left">The left.</param>
        /// <param name="right">The right.</param>
        /// <returns><c>true</c> if the native pointer is the same, <c>false</c> otherwise</returns>
        public static bool EqualsComObject<T>(T left, T right) where T : ComObject
        {
            return Equals(left, right);
        }

        ///<summary>
        /// Query this instance for a particular COM interface support.
        ///</summary>
        ///<typeparam name="T">The type of the COM interface to query</typeparam>
        ///<returns>An instance of the queried interface</returns>
        /// <exception cref="SharpGenException">If this object doesn't support the interface</exception>
        /// <msdn-id>ms682521</msdn-id>
        /// <unmanaged>IUnknown::QueryInterface</unmanaged>	
        /// <unmanaged-short>IUnknown::QueryInterface</unmanaged-short>
        public virtual T QueryInterface<T>() where T : ComObject
        {
            var result = QueryInterface(typeof(T).GetTypeInfo().GUID, out var parentPtr);
            result.CheckError();
            return MarshallingHelpers.FromPointer<T>(parentPtr);
        }

        /// <summary>
        /// Queries a managed object for a particular COM interface support (This method is a shortcut to <see cref="QueryInterface"/>)
        /// </summary>
        ///<typeparam name="T">The type of the COM interface to query</typeparam>
        /// <param name="comObject">The managed COM object.</param>
        ///<returns>An instance of the queried interface</returns>
        /// <msdn-id>ms682521</msdn-id>
        /// <unmanaged>IUnknown::QueryInterface</unmanaged>	
        /// <unmanaged-short>IUnknown::QueryInterface</unmanaged-short>
        public static T As<T>(object comObject) where T : ComObject
        {
            using var tempObject = new ComObject(Marshal.GetIUnknownForObject(comObject));
            return tempObject.QueryInterface<T>();
        }

        /// <summary>
        /// Queries a managed object for a particular COM interface support (This method is a shortcut to <see cref="QueryInterface"/>)
        /// </summary>
        ///<typeparam name="T">The type of the COM interface to query</typeparam>
        /// <param name="iunknownPtr">The managed COM object.</param>
        ///<returns>An instance of the queried interface</returns>
        /// <msdn-id>ms682521</msdn-id>
        /// <unmanaged>IUnknown::QueryInterface</unmanaged>	
        /// <unmanaged-short>IUnknown::QueryInterface</unmanaged-short>
        public static T As<T>(IntPtr iunknownPtr) where T : ComObject
        {
            using var tempObject = new ComObject(iunknownPtr);
            return tempObject.QueryInterface<T>();
        }

        /// <summary>
        /// Queries a managed object for a particular COM interface support.
        /// </summary>
        ///<typeparam name="T">The type of the COM interface to query</typeparam>
        /// <param name="comObject">The managed COM object.</param>
        ///<returns>An instance of the queried interface</returns>
        /// <msdn-id>ms682521</msdn-id>
        /// <unmanaged>IUnknown::QueryInterface</unmanaged>	
        /// <unmanaged-short>IUnknown::QueryInterface</unmanaged-short>
        public static T QueryInterface<T>(object comObject) where T : ComObject
        {
            using var tempObject = new ComObject(Marshal.GetIUnknownForObject(comObject));
            return tempObject.QueryInterface<T>();
        }

        /// <summary>
        /// Queries a managed object for a particular COM interface support.
        /// </summary>
        ///<typeparam name="T">The type of the COM interface to query</typeparam>
        /// <param name="comPointer">A pointer to a COM object.</param>
        ///<returns>An instance of the queried interface</returns>
        /// <msdn-id>ms682521</msdn-id>
        /// <unmanaged>IUnknown::QueryInterface</unmanaged>	
        /// <unmanaged-short>IUnknown::QueryInterface</unmanaged-short>
        public static T QueryInterfaceOrNull<T>(IntPtr comPointer) where T : ComObject
        {
            if (comPointer == IntPtr.Zero)
                return null;

            var guid = typeof(T).GetTypeInfo().GUID;
            var result = (Result) Marshal.QueryInterface(comPointer, ref guid, out var pointerPtr);
            return result.Failure ? null : MarshallingHelpers.FromPointer<T>(pointerPtr);
        }

        ///<summary>
        /// Query Interface for a particular interface support.
        ///</summary>
        ///<returns>An instance of the queried interface or null if it is not supported</returns>
        ///<returns></returns>
        /// <msdn-id>ms682521</msdn-id>
        /// <unmanaged>IUnknown::QueryInterface</unmanaged>	
        /// <unmanaged-short>IUnknown::QueryInterface</unmanaged-short>
        public virtual T QueryInterfaceOrNull<T>() where T : ComObject
        {
            return MarshallingHelpers.FromPointer<T>(QueryInterfaceOrNull(typeof(T).GetTypeInfo().GUID));
        }

        ///<summary>
        /// Query Interface for a particular interface support and attach to the given instance.
        ///</summary>
        ///<typeparam name="T"></typeparam>
        ///<returns></returns>
        protected void QueryInterfaceFrom<T>(T fromObject) where T : ComObject
        {
            fromObject.QueryInterface(GetType().GetTypeInfo().GUID, out var parentPtr);
            NativePointer = parentPtr;
        }

        /// <inheritdoc />
        protected override void DisposeCore(IntPtr nativePointer, bool disposing)
        {
            // Release the object
            if (disposing || Configuration.EnableReleaseOnFinalizer)
                ((IUnknown) this).Release();
        }

        protected bool Equals(ComObject other)
        {
            return EqualsComObject(this, other);
        }

        public override bool Equals(object obj)
        {
            if (ReferenceEquals(null, obj))
                return false;
            if (ReferenceEquals(this, obj))
                return true;
            if (obj is ComObject comObject)
                return NativePointer == comObject.NativePointer;
            return false;
        }

        public override int GetHashCode() => NativePointer.GetHashCode();

        public static bool operator ==(ComObject left, ComObject right) => Equals(left, right);

        public static bool operator !=(ComObject left, ComObject right) => !Equals(left, right);
    }
}