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Code Issues Releases Wiki Activity

Work to harden and extend functionality of CallMethodWithTypedBuf

pull/60/head
David Hall 2019-04-24 08:28:58 -06:00
parent 348fc7b7f7
commit 25502eb898
1 changed files with 20 additions and 11 deletions
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31
PInvoke/Shared/FunctionHelper.cs
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@ -1,4 +1,5 @@
using System;
using System.Collections.Generic;
using System.Text;
using Vanara.Extensions;
using Vanara.InteropServices;
@ -8,6 +9,8 @@ namespace Vanara.PInvoke
/// <summary>Generic functions to help with standard function patterns like getting a string from a method.</summary>
public static class FunctionHelper
{
private static readonly List<Win32Error> buffErrs = new List<Win32Error> { Win32Error.ERROR_MORE_DATA, Win32Error.ERROR_INSUFFICIENT_BUFFER, Win32Error.ERROR_BUFFER_OVERFLOW };
/// <summary>Delegate to get the size of memory allocated to a pointer.</summary>
/// <typeparam name="TSize">The type of the size result. This is usually <see cref="int"/> or <see cref="uint"/>.</typeparam>
/// <param name="ptr">The pointer to the memory in question.</param>
@ -44,7 +47,7 @@ namespace Vanara.PInvoke
/// <param name="sz">On input, the size of the capacity. On output, the number of characters written.</param>
/// <param name="err">The error.</param>
/// <returns><c>true</c> if buffer size is good; otherwise <c>false</c>.</returns>
public static bool ChkGoodBuf<TSize, TRet>(TSize sz, TRet err) where TSize : struct where TRet : IErrorProvider, IConvertible => !sz.Equals(default(TSize)) && (err.ToHRESULT() == (HRESULT)(Win32Error)Win32Error.ERROR_MORE_DATA || err.ToHRESULT() == (HRESULT)(Win32Error)Win32Error.ERROR_INSUFFICIENT_BUFFER);
public static bool ChkGoodBuf<TSize, TRet>(TSize sz, TRet err) where TSize : struct where TRet : IErrorProvider, IConvertible => !sz.Equals(default(TSize)) && buffErrs.ConvertAll(e => (HRESULT)e).Contains(err.ToHRESULT());
/// <summary>Calls a method with <see cref="StringBuilder"/> and gets the resulting string or error.</summary>
/// <typeparam name="TSize">The type of the size result. This is usually <see cref="int"/> or <see cref="uint"/>.</typeparam>
@ -87,20 +90,25 @@ namespace Vanara.PInvoke
return ret;
}
/// <summary>Calls a method with buffer for a type and gets the result or error.</summary>
/// <summary>
/// Calls a method with buffer for a type and gets the result or error.
/// </summary>
/// <typeparam name="TOut">The return type.</typeparam>
/// <typeparam name="TSize">The type of the size result. This is usually <see cref="int"/> or <see cref="uint"/>.</typeparam>
/// <typeparam name="TSize">The type of the size result. This is usually <see cref="int" /> or <see cref="uint" />.</typeparam>
/// <param name="getSize">Method to get the size of the buffer.</param>
/// <param name="method">The lambda or method to call into.</param>
/// <param name="result">The resulting value of <typeparamref name="TOut"/>.</param>
/// <param name="outConverter">An optional method to convert the pointer to the type specified by <typeparamref name="TOut"/>. By default, this will marshal the pointer to the structure.</param>
/// <returns>Resulting error or <see cref="Win32Error.ERROR_SUCCESS"/> on success.</returns>
public static Win32Error CallMethodWithTypedBuf<TOut, TSize>(SizeFunc<TSize> getSize, PtrFunc<TSize> method, out TOut result, Func<IntPtr, TSize, TOut> outConverter = null) where TSize : struct, IConvertible
/// <param name="result">The resulting value of <typeparamref name="TOut" />.</param>
/// <param name="outConverter">An optional method to convert the pointer to the type specified by <typeparamref name="TOut" />. By default, this will marshal the pointer to the structure.</param>
/// <param name="bufErr">The optional error <paramref name="method"/> returns when the buffer size is insufficient. If left <see langword="null"/>, then a list of well known errors will be used.</param>
/// <returns>
/// Resulting error or <see cref="Win32Error.ERROR_SUCCESS" /> on success.
/// </returns>
public static Win32Error CallMethodWithTypedBuf<TOut, TSize>(SizeFunc<TSize> getSize, PtrFunc<TSize> method, out TOut result, Func<IntPtr, TSize, TOut> outConverter = null, Win32Error? bufErr = null) where TSize : struct, IConvertible
{
TSize sz = default;
result = default;
var err = (getSize ?? GetSize)(ref sz);
if (err.Failed) return err;
if (err.Failed && (bufErr == null || bufErr.Value != err) && !buffErrs.Contains(err)) return err;
using (var buf = new SafeHGlobalHandle(sz.ToInt32(null)))
{
var ret = method(buf.DangerousGetHandle(), ref sz);
@ -108,7 +116,7 @@ namespace Vanara.PInvoke
return ret;
}
Win32Error GetSize(ref TSize sz1) { var serr = method(IntPtr.Zero, ref sz1); return serr == Win32Error.ERROR_INSUFFICIENT_BUFFER || serr == Win32Error.ERROR_MORE_DATA ? Win32Error.ERROR_SUCCESS : serr; }
Win32Error GetSize(ref TSize sz1) => method(IntPtr.Zero, ref sz1);
TOut Conv(IntPtr p, TSize s) => p.ToStructure<TOut>();
}
@ -118,10 +126,11 @@ namespace Vanara.PInvoke
/// <param name="method">The lambda or method to call into.</param>
/// <param name="getSize">Method to get the size of the buffer.</param>
/// <param name="outConverter">An optional method to convert the pointer to the type specified by <typeparamref name="TOut"/>. By default, this will marshal the pointer to the structure.</param>
/// <param name="bufErr">The optional error <paramref name="method"/> returns when the buffer size is insufficient. If left <see langword="null"/>, then a list of well known errors will be used.</param>
/// <returns>The resulting value of <typeparamref name="TOut"/>.</returns>
public static TOut CallMethodWithTypedBuf<TOut, TSize>(PtrFunc<TSize> method, SizeFunc<TSize> getSize = null, Func<IntPtr, TSize, TOut> outConverter = null) where TSize : struct, IConvertible
public static TOut CallMethodWithTypedBuf<TOut, TSize>(PtrFunc<TSize> method, SizeFunc<TSize> getSize = null, Func<IntPtr, TSize, TOut> outConverter = null, Win32Error? bufErr = null) where TSize : struct, IConvertible
{
CallMethodWithTypedBuf(getSize, method, out var res, outConverter).ThrowIfFailed();
CallMethodWithTypedBuf(getSize, method, out var res, outConverter, bufErr).ThrowIfFailed();
return res;
}
}