Opentk/Source/OpenTK/BindingsBase.cs
Fraser Waters 22760a4032 Fixes bugs in String marshalling.
Fixes two issues:
1. FreeStringArrayPtr used the wrong variable in the offset to
ReadIntPtr causing an access violation.
2. Better cleanup of memory in MarshalStringArrayToPtr when any alloc
fails.
2014-06-19 22:51:47 +01:00

252 lines
9.1 KiB
C#

#region License
//
// The Open Toolkit Library License
//
// Copyright (c) 2006 - 2009 the Open Toolkit library.
//
// 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.
//
#endregion
using System;
using System.Collections.Generic;
using System.Text;
using System.Reflection;
using System.Runtime.InteropServices;
using System.Diagnostics;
namespace OpenTK
{
/// <summary>
/// Provides a common foundation for all flat API bindings and implements the extension loading interface.
/// </summary>
public abstract class BindingsBase
{
#region Fields
/// <summary>
/// A reflection handle to the nested type that contains the function delegates.
/// </summary>
[Obsolete("Not used")]
readonly protected Type DelegatesClass;
/// <summary>
/// A refection handle to the nested type that contains core functions (i.e. not extensions).
/// </summary>
[Obsolete("Not used")]
readonly protected Type CoreClass;
/// <summary>
/// A mapping of core function names to MethodInfo handles.
/// </summary>
[Obsolete("Not used")]
readonly protected SortedList<string, MethodInfo> CoreFunctionMap;
bool rebuildExtensionList = true;
#endregion
#region Constructors
/// <summary>
/// Constructs a new BindingsBase instance.
/// </summary>
public BindingsBase()
{
}
#endregion
#region Protected Members
/// <summary>
/// Gets or sets a <see cref="System.Boolean"/> that indicates whether the list of supported extensions may have changed.
/// </summary>
protected bool RebuildExtensionList
{
get { return rebuildExtensionList; }
set { rebuildExtensionList = value; }
}
/// <summary>
/// Retrieves an unmanaged function pointer to the specified function.
/// </summary>
/// <param name="funcname">
/// A <see cref="System.String"/> that defines the name of the function.
/// </param>
/// <returns>
/// A <see cref="IntPtr"/> that contains the address of funcname or IntPtr.Zero,
/// if the function is not supported by the drivers.
/// </returns>
/// <remarks>
/// Note: some drivers are known to return non-zero values for unsupported functions.
/// Typical values include 1 and 2 - inheritors are advised to check for and ignore these
/// values.
/// </remarks>
protected abstract IntPtr GetAddress(string funcname);
/// <summary>
/// Gets an object that can be used to synchronize access to the bindings implementation.
/// </summary>
/// <remarks>This object should be unique across bindings but consistent between bindings
/// of the same type. For example, ES10.GL, OpenGL.GL and CL10.CL should all return
/// unique objects, but all instances of ES10.GL should return the same object.</remarks>
protected abstract object SyncRoot { get; }
/// <summary>
/// Marshals a pointer to a null-terminated byte array to the specified <c>StringBuilder</c>.
/// This method supports OpenTK and is not intended to be called by user code.
/// </summary>
/// <param name="ptr">A pointer to a null-terminated byte array.</param>
/// <param name="sb">The StringBuilder to receive the contents of the pointer.</param>
protected static void MarshalPtrToStringBuilder(IntPtr ptr, StringBuilder sb)
{
if (ptr == IntPtr.Zero)
throw new ArgumentException("ptr");
if (sb == null)
throw new ArgumentNullException("sb");
sb.Length = 0;
for (int i = 0; ; i++)
{
byte b = Marshal.ReadByte(ptr, i);
if (b == 0)
{
return;
}
sb.Append((char)b);
}
}
/// <summary>
/// Marshal a <c>System.String</c> to unmanaged memory.
/// The resulting string is encoded in ASCII and must be freed
/// with <c>FreeStringPtr</c>.
/// </summary>
/// <param name="str">The <c>System.String</c> to marshal.</param>
/// <returns>
/// An unmanaged pointer containing the marshalled string.
/// This pointer must be freed with <c>FreeStringPtr</c>
/// </returns>
protected static IntPtr MarshalStringToPtr(string str)
{
if (String.IsNullOrEmpty(str))
{
return IntPtr.Zero;
}
// Allocate a buffer big enough to hold the marshalled string.
// GetMaxByteCount() appears to allocate space for the final NUL
// character, but allocate an extra one just in case (who knows
// what old Mono version would do here.)
int max_count = Encoding.ASCII.GetMaxByteCount(str.Length) + 1;
IntPtr ptr = Marshal.AllocHGlobal(max_count);
if (ptr == IntPtr.Zero)
{
throw new OutOfMemoryException();
}
// Pin the managed string and convert it to ASCII using
// the pointer overload of System.Encoding.ASCII.GetBytes().
unsafe
{
fixed (char* pstr = str)
{
int actual_count = Encoding.ASCII.GetBytes(pstr, str.Length, (byte*)ptr, max_count);
Marshal.WriteByte(ptr, actual_count, 0); // Append '\0' at the end of the string
return ptr;
}
}
}
/// <summary>
/// Frees a marshalled string that allocated by <c>MarshalStringToPtr</c>.
/// </summary>
/// <param name="ptr">An unmanaged pointer allocated with <c>MarshalStringToPtr</c></param>
protected static void FreeStringPtr(IntPtr ptr)
{
Marshal.FreeHGlobal(ptr);
}
/// <summary>
/// Marshals a <c>System.String</c> array to unmanaged memory by calling
/// Marshal.AllocHGlobal for each element.
/// </summary>
/// <returns>An unmanaged pointer to an array of null-terminated strings</returns>
/// <param name="str_array">The string array to marshal.</param>
protected static IntPtr MarshalStringArrayToPtr(string[] str_array)
{
IntPtr ptr = IntPtr.Zero;
if (str_array != null && str_array.Length != 0)
{
ptr = Marshal.AllocHGlobal(str_array.Length * IntPtr.Size);
if (ptr == IntPtr.Zero)
{
throw new OutOfMemoryException();
}
int i = 0;
try
{
for (i = 0; i < str_array.Length; i++)
{
IntPtr str = MarshalStringToPtr(str_array[i]);
Marshal.WriteIntPtr(ptr, i * IntPtr.Size, str);
}
}
catch (OutOfMemoryException oom)
{
for (i = i - 1; i >= 0; --i)
{
Marshal.FreeHGlobal(Marshal.ReadIntPtr(ptr, i * IntPtr.Size));
}
Marshal.FreeHGlobal(ptr);
throw oom;
}
}
return ptr;
}
/// <summary>
/// Frees a marshalled string that allocated by <c>MarshalStringArrayToPtr</c>.
/// </summary>
/// <param name="ptr">An unmanaged pointer allocated with <c>MarshalStringArrayToPtr</c></param>
/// <param name="length">The length of the string array.</param>
protected static void FreeStringArrayPtr(IntPtr ptr, int length)
{
for (int i = 0; i < length; i++)
{
Marshal.FreeHGlobal(Marshal.ReadIntPtr(ptr, i * IntPtr.Size));
}
Marshal.FreeHGlobal(ptr);
}
#endregion
#region Internal Members
internal abstract void LoadEntryPoints();
#endregion
}
}