Vanara/Windows.Forms/Contexts/ActivationContext.cs

using System.Diagnostics.CodeAnalysis;
using System.Security;
using Vanara.PInvoke;
using static Vanara.PInvoke.Kernel32;

namespace Vanara.Windows.Forms;

/// <summary>Provides an activation context for a manifest file or PE image. On disposal, the context is deactivated.</summary>
/// <seealso cref="IDisposable"/>
[SuppressUnmanagedCodeSecurity]
public class ActivationContext : IDisposable
{
	private SafeHACTCTX hActCtx;
	private IntPtr localCookie;

	/// <summary>Initializes a new instance of the <see cref="ActivationContext"/> class.</summary>
	/// <exception cref="InvalidOperationException">No current activation context exists.</exception>
	public ActivationContext() => hActCtx = SafeHACTCTX.GetCurrent();

	/// <summary>Initializes a new instance of the <see cref="ActivationContext"/> class.</summary>
	/// <param name="source">The path of a manifest file. Do not use this constructor if specifying a PE image.</param>
	/// <param name="assemblyDirectory">
	/// The base directory in which to perform private assembly probing if assemblies in the activation context are not present in the
	/// system-wide store.
	/// </param>
	public ActivationContext(string source, string? assemblyDirectory = null)
	{
		var actctx = new ACTCTX(source);
		CreateAndAttach(ref actctx, assemblyDirectory: assemblyDirectory);
	}

	/// <summary>Initializes a new instance of the <see cref="ActivationContext"/> class.</summary>
	/// <param name="peImagePath">Specifies the path of PE image (EXE or DLL file) to be used to create the activation context.</param>
	/// <param name="resourceName">
	/// The resource name to be loaded from the PE. If the resource name is an integer, set this member using MAKEINTRESOURCE.
	/// </param>
	/// <param name="assemblyDirectory">
	/// The base directory in which to perform private assembly probing if assemblies in the activation context are not present in the
	/// system-wide store.
	/// </param>
	/// <param name="appName">
	/// The name of the current application. If the value of this member is set to null, the name of the executable that launched the
	/// current process is used.
	/// </param>
	/// <param name="langId">Specifies the language manifest that should be used. The default is the current user's current UI language.</param>
	/// <param name="processor">Identifies the type of processor used. Specifies the system's processor architecture.</param>
	/// <param name="setAsProcessDefault">if set to <c>true</c> [set as process default].</param>
	public ActivationContext(string peImagePath, string resourceName, string? assemblyDirectory = null, string? appName = null, ushort langId = 0, ProcessorArchitecture processor = 0, bool setAsProcessDefault = false)
	{
		var actctx = new ACTCTX(peImagePath ?? throw new ArgumentNullException(nameof(peImagePath)));
		if (resourceName == null) throw new ArgumentNullException(nameof(resourceName));
		CreateAndAttach(ref actctx, resourceName, assemblyDirectory, appName, langId, processor, setAsProcessDefault);
	}

	/// <summary>Initializes a new instance of the <see cref="ActivationContext"/> class.</summary>
	/// <param name="hInst">
	/// Specifies the handle to an already opened module (EXE or DLL file) to be used to create the activation context.
	/// </param>
	/// <param name="resourceName">
	/// The resource name to be loaded from the PE. If the resource name is an integer, set this member using MAKEINTRESOURCE.
	/// </param>
	/// <param name="assemblyDirectory">
	/// The base directory in which to perform private assembly probing if assemblies in the activation context are not present in the
	/// system-wide store.
	/// </param>
	/// <param name="appName">
	/// The name of the current application. If the value of this member is set to null, the name of the executable that launched the
	/// current process is used.
	/// </param>
	/// <param name="langId">Specifies the language manifest that should be used. The default is the current user's current UI language.</param>
	/// <param name="processor">Identifies the type of processor used. Specifies the system's processor architecture.</param>
	/// <param name="setAsProcessDefault">if set to <c>true</c> [set as process default].</param>
	public ActivationContext(HINSTANCE hInst, string resourceName, string? assemblyDirectory = null, string? appName = null, ushort langId = 0, ProcessorArchitecture processor = 0, bool setAsProcessDefault = false)
	{
		if (hInst.IsNull) throw new ArgumentNullException(nameof(hInst));
		if (resourceName == null) throw new ArgumentNullException(nameof(resourceName));
		var actctx = ACTCTX.Empty;
		actctx.hModule = hInst;
		CreateAndAttach(ref actctx, resourceName, assemblyDirectory, appName, langId, processor, setAsProcessDefault);
	}

	/// <summary>Initializes a new instance of the <see cref="ActivationContext"/> class.</summary>
	/// <param name="context">An activation context structure.</param>
	public ActivationContext(in ACTCTX context)
	{
		Create(context);
		Activate();
	}

	/// <summary>Gets the local cookie associated with the activation.</summary>
	public IntPtr Cookie => localCookie;

	/// <summary>Gets a value indicating if the context is invalid.</summary>
	public bool IsInvalid => hActCtx.IsNull;

	/// <inheritdoc/>
	public void Dispose()
	{
		if (localCookie != IntPtr.Zero && DeactivateActCtx(0, localCookie))
			localCookie = IntPtr.Zero;
		hActCtx.Dispose();
		GC.SuppressFinalize(this);
	}

	private void Activate()
	{
		if (!ActivateActCtx(hActCtx, out localCookie)) Win32Error.ThrowLastError();
	}

	[MemberNotNull(nameof(hActCtx))]
	private void Create(in ACTCTX context)
	{
		hActCtx = CreateActCtx(context);
		if (hActCtx.IsInvalid) Win32Error.ThrowLastError();
	}

	[MemberNotNull(nameof(hActCtx))]
	private void CreateAndAttach(ref ACTCTX actctx, string? resourceName = null, string? assemblyDirectory = null, string? appName = null, ushort langId = 0, ProcessorArchitecture processor = 0, bool setAsProcessDefault = false)
	{
		if (resourceName != null)
		{
			actctx.lpResourceName = resourceName;
			actctx.dwFlags |= ActCtxFlags.ACTCTX_FLAG_RESOURCE_NAME_VALID;
		}
		if (assemblyDirectory != null)
		{
			actctx.lpAssemblyDirectory = assemblyDirectory;
			actctx.dwFlags |= ActCtxFlags.ACTCTX_FLAG_ASSEMBLY_DIRECTORY_VALID;
		}
		if (appName != null)
		{
			actctx.lpApplicationName = appName;
			actctx.dwFlags |= ActCtxFlags.ACTCTX_FLAG_APPLICATION_NAME_VALID;
		}
		if (langId != 0)
		{
			actctx.wLangId = langId;
			actctx.dwFlags |= ActCtxFlags.ACTCTX_FLAG_LANGID_VALID;
		}
		if (processor != 0)
		{
			actctx.wProcessorArchitecture = processor;
			actctx.dwFlags |= ActCtxFlags.ACTCTX_FLAG_PROCESSOR_ARCHITECTURE_VALID;
		}
		if (setAsProcessDefault)
		{
			actctx.dwFlags |= ActCtxFlags.ACTCTX_FLAG_SET_PROCESS_DEFAULT;
		}
		Create(actctx);
		Activate();
	}
}