GtkSharp/glib/GType.cs
Andrés G. Aragoneses 6d626a24a7 glib: avoid a delegate to be GCed which caused a NRE (bxc#13113)
What seemed to be a race condition (because of not happenning 100% of
the times) ended up being an early garbage collection of a delegate that
was still referenced by an unmanaged struct without having a managed
counterpart [1].

The consequence of this was a NullReferenceException happening in a line
which didn't have a dereference of a null object. The way to reproduce it
deterministically 100% of the times was setting the env var MONO_NO_SMP.

[1] http://www.mono-project.com/Interop_with_Native_Libraries#Memory_Boundaries
2013-07-17 14:24:02 +02:00

452 lines
14 KiB
C#
Executable file

// GLib.Type.cs - GLib GType class implementation
//
// Authors: Mike Kestner <mkestner@speakeasy.net>
// Andres G. Aragoneses <knocte@gmail.com>
//
// Copyright (c) 2003 Mike Kestner
// Copyright (c) 2003 Novell, Inc.
// Copyright (c) 2013 Andres G. Aragoneses
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of version 2 of the Lesser GNU General
// Public License as published by the Free Software Foundation.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this program; if not, write to the
// Free Software Foundation, Inc., 59 Temple Place - Suite 330,
// Boston, MA 02111-1307, USA.
namespace GLib {
using System;
using System.Collections.Generic;
using System.IO;
using System.Reflection;
using System.Runtime.InteropServices;
using System.Text;
public delegate System.Type TypeResolutionHandler (GLib.GType gtype, string gtype_name);
[StructLayout(LayoutKind.Sequential)]
public struct GType {
IntPtr val;
[UnmanagedFunctionPointer (CallingConvention.Cdecl)]
internal delegate void ClassInitDelegate (IntPtr gobject_class_handle);
struct GTypeInfo {
public ushort class_size;
public IntPtr base_init;
public IntPtr base_finalize;
public ClassInitDelegate class_init;
public IntPtr class_finalize;
public IntPtr class_data;
public ushort instance_size;
public ushort n_preallocs;
public IntPtr instance_init;
public IntPtr value_table;
}
struct GTypeQuery {
public IntPtr type;
public IntPtr type_name;
public uint class_size;
public uint instance_size;
}
public GType (IntPtr val)
{
this.val = val;
}
public static GType FromName (string native_name)
{
return new GType (g_type_from_name (native_name));
}
public static readonly GType Invalid = new GType ((IntPtr) TypeFundamentals.TypeInvalid);
public static readonly GType None = new GType ((IntPtr) TypeFundamentals.TypeNone);
public static readonly GType Interface = new GType ((IntPtr) TypeFundamentals.TypeInterface);
public static readonly GType Char = new GType ((IntPtr) TypeFundamentals.TypeChar);
public static readonly GType UChar = new GType ((IntPtr) TypeFundamentals.TypeUChar);
public static readonly GType Boolean = new GType ((IntPtr) TypeFundamentals.TypeBoolean);
public static readonly GType Int = new GType ((IntPtr) TypeFundamentals.TypeInt);
public static readonly GType UInt = new GType ((IntPtr) TypeFundamentals.TypeUInt);
public static readonly GType Long = new GType ((IntPtr) TypeFundamentals.TypeLong);
public static readonly GType ULong = new GType ((IntPtr) TypeFundamentals.TypeULong);
public static readonly GType Int64 = new GType ((IntPtr) TypeFundamentals.TypeInt64);
public static readonly GType UInt64 = new GType ((IntPtr) TypeFundamentals.TypeUInt64);
public static readonly GType Enum = new GType ((IntPtr) TypeFundamentals.TypeEnum);
public static readonly GType Flags = new GType ((IntPtr) TypeFundamentals.TypeFlags);
public static readonly GType Float = new GType ((IntPtr) TypeFundamentals.TypeFloat);
public static readonly GType Double = new GType ((IntPtr) TypeFundamentals.TypeDouble);
public static readonly GType String = new GType ((IntPtr) TypeFundamentals.TypeString);
public static readonly GType Pointer = new GType ((IntPtr) TypeFundamentals.TypePointer);
public static readonly GType Boxed = new GType ((IntPtr) TypeFundamentals.TypeBoxed);
public static readonly GType Param = new GType ((IntPtr) TypeFundamentals.TypeParam);
public static readonly GType Object = new GType ((IntPtr) TypeFundamentals.TypeObject);
static IDictionary<IntPtr, Type> types = new Dictionary<IntPtr, Type> ();
static IDictionary<Type, GType> gtypes = new Dictionary<Type, GType> ();
public static void Register (GType native_type, System.Type type)
{
lock (types) {
if (native_type != GType.Pointer && native_type != GType.Boxed && native_type != ManagedValue.GType)
types[native_type.Val] = type;
if (type != null)
gtypes[type] = native_type;
}
}
static GType ()
{
if (!GLib.Thread.Supported)
GLib.Thread.Init ();
g_type_init ();
Register (GType.Char, typeof (sbyte));
Register (GType.UChar, typeof (byte));
Register (GType.Boolean, typeof (bool));
Register (GType.Int, typeof (int));
Register (GType.UInt, typeof (uint));
Register (GType.Int64, typeof (long));
Register (GType.UInt64, typeof (ulong));
Register (GType.Float, typeof (float));
Register (GType.Double, typeof (double));
Register (GType.String, typeof (string));
Register (GType.Pointer, typeof (IntPtr));
Register (GType.Object, typeof (GLib.Object));
Register (GType.Pointer, typeof (IntPtr));
// One-way mapping
gtypes[typeof (char)] = GType.UInt;
}
public static explicit operator GType (System.Type type)
{
GType gtype;
lock (types) {
if (gtypes.ContainsKey (type))
return gtypes[type];
}
if (type.IsSubclassOf (typeof (GLib.Object))) {
gtype = GLib.Object.LookupGType (type);
Register (gtype, type);
return gtype;
}
PropertyInfo pi = type.GetProperty ("GType", BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Static | BindingFlags.FlattenHierarchy);
if (pi != null)
gtype = (GType) pi.GetValue (null, null);
else if (type.IsDefined (typeof (GTypeAttribute), false)) {
GTypeAttribute gattr = (GTypeAttribute)Attribute.GetCustomAttribute (type, typeof (GTypeAttribute), false);
pi = gattr.WrapperType.GetProperty ("GType", BindingFlags.Public | BindingFlags.Static);
gtype = (GType) pi.GetValue (null, null);
} else if (type.IsSubclassOf (typeof (GLib.Opaque)))
gtype = GType.Pointer;
else
gtype = ManagedValue.GType;
Register (gtype, type);
return gtype;
}
static string GetQualifiedName (string cname)
{
if (string.IsNullOrEmpty (cname))
return null;
for (int i = 1; i < cname.Length; i++) {
if (System.Char.IsUpper (cname[i])) {
if (i == 1 && cname [0] == 'G')
return "GLib." + cname.Substring (1);
else
return cname.Substring (0, i) + "." + cname.Substring (i);
}
}
return null;
}
public static explicit operator Type (GType gtype)
{
return LookupType (gtype.Val);
}
public static void Init ()
{
// cctor already calls g_type_init.
}
public static event TypeResolutionHandler ResolveType;
public static Type LookupType (IntPtr typeid)
{
lock (types) {
if (types.ContainsKey (typeid))
return types[typeid];
}
string native_name = Marshaller.Utf8PtrToString (g_type_name (typeid));
if (ResolveType != null) {
GLib.GType gt = new GLib.GType (typeid);
Delegate[] invocation_list = ResolveType.GetInvocationList ();
foreach (Delegate d in invocation_list) {
TypeResolutionHandler handler = (TypeResolutionHandler) d;
System.Type tmp = handler (gt, native_name);
if (tmp != null) {
Register (gt, tmp);
return tmp;
}
}
}
string type_name = GetQualifiedName (native_name);
if (type_name == null)
return null;
Type result = null;
Assembly[] assemblies = (Assembly[]) AppDomain.CurrentDomain.GetAssemblies ().Clone ();
foreach (Assembly asm in assemblies) {
result = asm.GetType (type_name);
if (result != null)
break;
}
if (result == null) {
// Because of lazy loading of references, it's possible the type's assembly
// needs to be loaded. We will look for it by name in the references of
// the currently loaded assemblies. Hopefully a recursive traversal is
// not needed. We avoid one for now because of problems experienced
// in a patch from bug #400595, and a desire to keep memory usage low
// by avoiding a complete loading of all dependent assemblies.
string ns = type_name.Substring (0, type_name.LastIndexOf ('.'));
string asm_name = ns.ToLower ().Replace ('.', '-') + "-sharp";
foreach (Assembly asm in assemblies) {
foreach (AssemblyName ref_name in asm.GetReferencedAssemblies ()) {
if (ref_name.Name != asm_name)
continue;
try {
string asm_dir = Path.GetDirectoryName (asm.Location);
Assembly ref_asm;
if (File.Exists (Path.Combine (asm_dir, ref_name.Name + ".dll")))
ref_asm = Assembly.LoadFrom (Path.Combine (asm_dir, ref_name.Name + ".dll"));
else
ref_asm = Assembly.Load (ref_name);
result = ref_asm.GetType (type_name);
if (result != null)
break;
} catch (Exception) {
/* Failure to load a referenced assembly is not an error */
}
}
if (result != null)
break;
}
}
Register (new GType (typeid), result);
return result;
}
public IntPtr Val {
get { return val; }
}
public static bool operator == (GType a, GType b)
{
return a.Val == b.Val;
}
public static bool operator != (GType a, GType b)
{
return a.Val != b.Val;
}
public override bool Equals (object o)
{
if (!(o is GType))
return false;
return ((GType) o) == this;
}
public override int GetHashCode ()
{
return val.GetHashCode ();
}
public override string ToString ()
{
return Marshaller.Utf8PtrToString (g_type_name (val));
}
public IntPtr GetClassPtr ()
{
IntPtr klass = g_type_class_peek (val);
if (klass == IntPtr.Zero)
klass = g_type_class_ref (val);
return klass;
}
public IntPtr GetDefaultInterfacePtr ()
{
IntPtr klass = g_type_default_interface_peek (val);
if (klass == IntPtr.Zero)
klass = g_type_default_interface_ref (val);
return klass;
}
public GType GetBaseType ()
{
IntPtr parent = g_type_parent (this.Val);
return parent == IntPtr.Zero ? GType.None : new GType (parent);
}
public GType GetThresholdType ()
{
GType curr_type = this;
while (curr_type.ToString ().StartsWith ("__gtksharp_"))
curr_type = curr_type.GetBaseType ();
return curr_type;
}
public uint GetClassSize ()
{
GTypeQuery query;
g_type_query (this.Val, out query);
return query.class_size;
}
internal void EnsureClass ()
{
if (g_type_class_peek (val) == IntPtr.Zero)
g_type_class_ref (val);
}
static int type_uid;
static string BuildEscapedName (System.Type t)
{
string qn = t.FullName;
// Just a random guess
StringBuilder sb = new StringBuilder (20 + qn.Length);
sb.Append ("__gtksharp_");
sb.Append (type_uid++);
sb.Append ("_");
foreach (char c in qn) {
if ((c >= '0' && c <= '9') || (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z'))
sb.Append (c);
else if (c == '.')
sb.Append ('_');
else if ((uint) c <= byte.MaxValue) {
sb.Append ('+');
sb.Append (((byte) c).ToString ("x2"));
} else {
sb.Append ('-');
sb.Append (((uint) c).ToString ("x4"));
}
}
return sb.ToString ();
}
internal static GType RegisterGObjectType (Object.ClassInitializer gobject_class_initializer)
{
GType parent_gtype = LookupGObjectType (gobject_class_initializer.Type.BaseType);
string name = BuildEscapedName (gobject_class_initializer.Type);
IntPtr native_name = GLib.Marshaller.StringToPtrGStrdup (name);
GTypeQuery query;
g_type_query (parent_gtype.Val, out query);
GTypeInfo info = new GTypeInfo ();
info.class_size = (ushort) query.class_size;
info.instance_size = (ushort) query.instance_size;
info.class_init = gobject_class_initializer.ClassInitManagedDelegate;
GType gtype = new GType (g_type_register_static (parent_gtype.Val, native_name, ref info, 0));
GLib.Marshaller.Free (native_name);
Register (gtype, gobject_class_initializer.Type);
return gtype;
}
internal static GType LookupGObjectType (System.Type t)
{
lock (types) {
if (gtypes.ContainsKey (t))
return gtypes [t];
}
PropertyInfo pi = t.GetProperty ("GType", BindingFlags.DeclaredOnly | BindingFlags.Static | BindingFlags.Public);
if (pi != null)
return (GType) pi.GetValue (null, null);
return GLib.Object.RegisterGType (t);
}
internal static IntPtr ValFromInstancePtr (IntPtr handle)
{
if (handle == IntPtr.Zero)
return IntPtr.Zero;
// First field of instance is a GTypeClass*.
IntPtr klass = Marshal.ReadIntPtr (handle);
// First field of GTypeClass is a GType.
return Marshal.ReadIntPtr (klass);
}
internal static bool Is (IntPtr type, GType is_a_type)
{
return g_type_is_a (type, is_a_type.Val);
}
public bool IsInstance (IntPtr raw)
{
return GType.Is (ValFromInstancePtr (raw), this);
}
[DllImport ("libgobject-2.0-0.dll", CallingConvention = CallingConvention.Cdecl)]
static extern IntPtr g_type_class_peek (IntPtr gtype);
[DllImport ("libgobject-2.0-0.dll", CallingConvention = CallingConvention.Cdecl)]
static extern IntPtr g_type_class_ref (IntPtr gtype);
[DllImport ("libgobject-2.0-0.dll", CallingConvention = CallingConvention.Cdecl)]
static extern IntPtr g_type_default_interface_peek (IntPtr gtype);
[DllImport ("libgobject-2.0-0.dll", CallingConvention = CallingConvention.Cdecl)]
static extern IntPtr g_type_default_interface_ref (IntPtr gtype);
[DllImport ("libgobject-2.0-0.dll", CallingConvention = CallingConvention.Cdecl)]
static extern IntPtr g_type_from_name (string name);
[DllImport ("libgobject-2.0-0.dll", CallingConvention = CallingConvention.Cdecl)]
static extern void g_type_init ();
[DllImport ("libgobject-2.0-0.dll", CallingConvention = CallingConvention.Cdecl)]
static extern IntPtr g_type_name (IntPtr raw);
[DllImport ("libgobject-2.0-0.dll", CallingConvention = CallingConvention.Cdecl)]
static extern IntPtr g_type_parent (IntPtr type);
[DllImport ("libgobject-2.0-0.dll", CallingConvention = CallingConvention.Cdecl)]
static extern void g_type_query (IntPtr type, out GTypeQuery query);
[DllImport ("libgobject-2.0-0.dll", CallingConvention = CallingConvention.Cdecl)]
static extern IntPtr g_type_register_static (IntPtr parent, IntPtr name, ref GTypeInfo info, int flags);
[DllImport ("libgobject-2.0-0.dll", CallingConvention = CallingConvention.Cdecl)]
static extern bool g_type_is_a (IntPtr type, IntPtr is_a_type);
}
}