GtkSharp/generator/ManagedCallString.cs
Bertrand Lorentz e48ac63d54 generator: Dispose ownable method parameters in VM callback (bxc#237)
Some virtual methods are passed a native object that is wrapped in an
IDisposable managed object, which is then passed on to the managed
overrides. We need to dispose those objects as soon as possible,
otherwise their native counterpart will not be freed until the next
garbage collection. Requiring the overrides to dispose them would be
cumbersome and error-prone.

Those parameters will now be disposed in a finally {...} block, after
the virtual method has returned. This means that overrides should not
keep a reference to such a parameter outside of the scope of the method,
as it will be diposed when the method returns.

This change only affects Cairo.Context parameter for now, but it was
particularly needed for them, as they could happily hold on to tens of
MBs of memory until the next garbage collection.
2013-11-09 16:26:17 +01:00

194 lines
5.2 KiB
C#

// GtkSharp.Generation.ManagedCallString.cs - The ManagedCallString Class.
//
// Author: Mike Kestner <mkestner@speakeasy.net>
//
// Copyright (c) 2003 Mike Kestner
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of version 2 of the 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
// General Public License for more details.
//
// You should have received a copy of the GNU 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 GtkSharp.Generation {
using System;
using System.Collections.Generic;
using System.IO;
public class ManagedCallString {
IDictionary<Parameter, bool> parms = new Dictionary<Parameter, bool> ();
IList<Parameter> dispose_params = new List<Parameter> ();
string error_param = null;
string user_data_param = null;
string destroy_param = null;
public ManagedCallString (Parameters parms)
{
for (int i = 0; i < parms.Count; i ++) {
Parameter p = parms [i];
if (p.IsLength && i > 0 && parms [i-1].IsString)
continue;
else if (p.Scope == "notified") {
user_data_param = parms[i+1].Name;
destroy_param = parms[i+2].Name;
i += 2;
} else if ((p.IsCount || p.IsUserData) && parms.IsHidden (p)) {
user_data_param = p.Name;
continue;
} else if (p is ErrorParameter) {
error_param = p.Name;
continue;
}
bool special = false;
if (p.PassAs != String.Empty && (p.Name != p.FromNative (p.Name)))
special = true;
else if (p.Generatable is CallbackGen)
special = true;
this.parms.Add (p, special);
if (p.IsOwnable) {
dispose_params.Add (p);
}
}
}
public bool HasOutParam {
get {
foreach (Parameter p in parms.Keys) {
if (p.PassAs == "out")
return true;
}
return false;
}
}
public bool HasDisposeParam {
get { return dispose_params.Count > 0; }
}
public string Unconditional (string indent) {
string ret = "";
if (error_param != null)
ret = indent + error_param + " = IntPtr.Zero;\n";
foreach (Parameter p in dispose_params) {
ret += indent + p.CSType + " my" + p.Name + " = null;\n";
}
return ret;
}
public string Setup (string indent)
{
string ret = "";
foreach (Parameter p in parms.Keys) {
if (parms [p] == false) {
continue;
}
IGeneratable igen = p.Generatable;
if (igen is CallbackGen) {
if (user_data_param == null)
ret += indent + String.Format ("{0} {1}_invoker = new {0} ({1});\n", (igen as CallbackGen).InvokerName, p.Name);
else if (destroy_param == null)
ret += indent + String.Format ("{0} {1}_invoker = new {0} ({1}, {2});\n", (igen as CallbackGen).InvokerName, p.Name, user_data_param);
else
ret += indent + String.Format ("{0} {1}_invoker = new {0} ({1}, {2}, {3});\n", (igen as CallbackGen).InvokerName, p.Name, user_data_param, destroy_param);
} else {
ret += indent + igen.QualifiedName + " my" + p.Name;
if (p.PassAs == "ref")
ret += " = " + p.FromNative (p.Name);
ret += ";\n";
}
}
foreach (Parameter p in dispose_params) {
ret += indent + "my" + p.Name + " = " + p.FromNative (p.Name) + ";\n";
}
return ret;
}
public override string ToString ()
{
if (parms.Count < 1)
return "";
string[] result = new string [parms.Count];
int i = 0;
foreach (Parameter p in parms.Keys) {
result [i] = p.PassAs == "" ? "" : p.PassAs + " ";
if (p.Generatable is CallbackGen) {
result [i] += p.Name + "_invoker.Handler";
} else {
if (parms [p] || dispose_params.Contains(p)) {
// Parameter was declared and marshalled earlier
result [i] += "my" + p.Name;
} else {
result [i] += p.FromNative (p.Name);
}
}
i++;
}
return String.Join (", ", result);
}
public string Finish (string indent)
{
string ret = "";
foreach (Parameter p in parms.Keys) {
if (parms [p] == false) {
continue;
}
IGeneratable igen = p.Generatable;
if (igen is CallbackGen)
continue;
else if (igen is StructBase || igen is ByRefGen)
ret += indent + String.Format ("if ({0} != IntPtr.Zero) System.Runtime.InteropServices.Marshal.StructureToPtr (my{0}, {0}, false);\n", p.Name);
else if (igen is IManualMarshaler)
ret += String.Format ("{0}{1} = {2};", indent, p.Name, (igen as IManualMarshaler).AllocNative ("my" + p.Name));
else
ret += indent + p.Name + " = " + igen.CallByName ("my" + p.Name) + ";\n";
}
return ret;
}
public string DisposeParams (string indent)
{
string ret = "";
foreach (Parameter p in dispose_params) {
string name = "my" + p.Name;
string disp_name = "disposable_" + p.Name;
ret += indent + "var " + disp_name + " = " + name + " as IDisposable;\n";
ret += indent + "if (" + disp_name + " != null)\n";
ret += indent + "\t" + disp_name + ".Dispose ();\n";
}
return ret;
}
}
}