gstreamer/sources/custom/DynamicSignal.cs

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// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library 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 library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
//
//
// Copyright (C) 2006 Novell Inc.
// Copyright (C) 2009 Sebastian Dröge <sebastian.droege@collabora.co.uk>
// Copyright (C) 2013 Stephan Sundermann <stephansundermann@gmail.com>
//
// This class implements functions to bind callbacks to GObject signals
// dynamically and to emit signals dynamically.
//
//
using GLib;
using System;
using System.Reflection;
using System.Runtime.InteropServices;
using System.Collections;
namespace Gst
{
[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
delegate void GClosureMarshal (IntPtr closure, ref GLib.Value retval, uint argc, IntPtr argsPtr,
IntPtr invocation_hint, IntPtr data);
public delegate void SignalHandler (object o, SignalArgs args);
public static class DynamicSignal
{
private static readonly int gvalue_struct_size = Marshal.SizeOf (typeof(GLib.Value));
class ObjectSignalKey
{
object o;
string signal_name;
public ObjectSignalKey (object o, string name)
{
this.o = o;
signal_name = name;
}
public override bool Equals (object o)
{
if (o is ObjectSignalKey) {
ObjectSignalKey k = (ObjectSignalKey)o;
return k.o.Equals (this.o) && signal_name.Equals (k.signal_name);
}
return base.Equals (o);
}
public override int GetHashCode ()
{
return o.GetHashCode () ^ signal_name.GetHashCode ();
}
}
class SignalInfo : IDisposable
{
uint handlerId;
IntPtr closure;
Delegate registeredHandler;
Type argsType;
GCHandle gch;
public IntPtr Closure {
get {
return closure;
}
set {
closure = value;
}
}
public uint HandlerId {
get {
return handlerId;
}
set {
handlerId = value;
}
}
public Delegate RegisteredHandler {
get {
return registeredHandler;
}
set {
registeredHandler = value;
}
}
public Type ArgsType {
get {
return argsType;
}
set {
argsType = value;
}
}
public SignalInfo (uint handlerId, IntPtr closure, Delegate registeredHandler, GCHandle gch)
{
this.handlerId = handlerId;
this.closure = closure;
this.registeredHandler = registeredHandler;
this.gch = gch;
if (!IsValidDelegate (registeredHandler))
throw new Exception ("Invalid delegate");
MethodInfo mi = registeredHandler.Method;
ParameterInfo[] parms = mi.GetParameters ();
this.argsType = parms [1].ParameterType;
}
public void UpdateArgsType (Delegate d)
{
if (!IsCompatibleDelegate (d))
throw new Exception ("Incompatible delegate");
MethodInfo mi = d.Method;
ParameterInfo[] parms = mi.GetParameters ();
Type t1 = parms [1].ParameterType;
Type t2 = argsType;
if (t1 == t2)
return;
if (t1.IsSubclassOf (t2))
argsType = t1;
else if (t2.IsSubclassOf (t1))
argsType = t2;
else
throw new Exception ("Incompatible delegate");
}
public bool IsCompatibleDelegate (Delegate d)
{
if (!IsValidDelegate (d))
return false;
MethodInfo mi = d.Method;
ParameterInfo[] parms = mi.GetParameters ();
if (parms [1].ParameterType != this.argsType &&
!parms [1].ParameterType.IsSubclassOf (this.argsType) &&
!this.argsType.IsSubclassOf (parms [1].ParameterType))
return false;
return true;
}
public void Dispose ()
{
registeredHandler = null;
gch.Free ();
GC.SuppressFinalize (this);
}
public static bool IsValidDelegate (Delegate d)
{
MethodInfo mi = d.Method;
if (mi.ReturnType != typeof(void))
return false;
ParameterInfo[] parms = mi.GetParameters ();
if (parms.Length != 2)
return false;
if (parms [1].ParameterType != typeof(GLib.SignalArgs) &&
!parms [1].ParameterType.IsSubclassOf (typeof(GLib.SignalArgs)))
return false;
return true;
}
}
static Hashtable SignalHandlers = new Hashtable ();
static GClosureMarshal marshalHandler = new GClosureMarshal (OnMarshal);
public static void Connect (GLib.Object o, string name, SignalHandler handler)
{
Connect (o, name, false, (Delegate)handler);
}
public static void Connect (GLib.Object o, string name,
bool after, SignalHandler handler)
{
Connect (o, name, after, (Delegate)handler);
}
public static void Connect (GLib.Object o, string name, Delegate handler)
{
Connect (o, name, false, handler);
}
public static void Connect (GLib.Object o, string name,
bool after, Delegate handler)
{
Delegate newHandler;
ObjectSignalKey k = new ObjectSignalKey (o, name);
if (!SignalInfo.IsValidDelegate (handler))
throw new Exception ("Invalid delegate");
if (SignalHandlers [k] != null) {
SignalInfo si = (SignalInfo)SignalHandlers [k];
if (!si.IsCompatibleDelegate (handler))
throw new Exception ("Incompatible delegate");
newHandler = Delegate.Combine (si.RegisteredHandler, handler);
si.UpdateArgsType (handler);
si.RegisteredHandler = newHandler;
} else {
if (!SignalInfo.IsValidDelegate (handler))
throw new Exception ("Invalid delegate");
// Let's allocate 64bytes for the GClosure, it should be more than necessary.
IntPtr closure = g_closure_new_simple (64, IntPtr.Zero);
GCHandle gch = GCHandle.Alloc (k);
g_closure_set_meta_marshal (closure, (IntPtr)gch, marshalHandler);
uint signalId = g_signal_connect_closure (o.Handle, name, closure, after);
SignalHandlers.Add (k, new SignalInfo (signalId, closure, handler, gch));
}
}
public static void Disconnect (GLib.Object o, string name, Delegate handler)
{
ObjectSignalKey k = new ObjectSignalKey (o, name);
if (SignalHandlers [k] != null) {
SignalInfo si = (SignalInfo)SignalHandlers [k];
Delegate newHandler = Delegate.Remove (si.RegisteredHandler, handler);
if (newHandler == null || handler == null) {
g_signal_handler_disconnect (o.Handle, si.HandlerId);
SignalHandlers.Remove (k);
si.Dispose ();
} else {
si.RegisteredHandler = newHandler;
}
}
}
static void OnMarshal (IntPtr closure, ref GLib.Value retval, uint argc, IntPtr argsPtr,
IntPtr ihint, IntPtr data)
{
object[] args = new object[argc - 1];
object o = ((GLib.Value)Marshal.PtrToStructure (argsPtr, typeof(GLib.Value))).Val;
for (int i = 1; i < argc; i++) {
IntPtr struct_ptr = (IntPtr)((long)argsPtr + (i * gvalue_struct_size));
GLib.Value argument = (GLib.Value)Marshal.PtrToStructure (struct_ptr, typeof(GLib.Value));
args [i - 1] = argument.Val;
}
if (data == IntPtr.Zero) {
Console.Error.WriteLine ("No available data");
return;
}
ObjectSignalKey k = (ObjectSignalKey)((GCHandle)data).Target;
if (k != null) {
SignalInfo si = (SignalInfo)SignalHandlers [k];
GLib.SignalArgs arg = (GLib.SignalArgs)Activator.CreateInstance (si.ArgsType);
arg.Args = args;
si.RegisteredHandler.DynamicInvoke (new object[] { o, arg });
if (arg.RetVal != null) {
retval.Val = arg.RetVal;
}
}
}
[DllImport ("gobject-2.0-0.dll", CallingConvention = CallingConvention.Cdecl)]
static extern IntPtr g_closure_new_simple (int size, IntPtr data);
[DllImport ("gobject-2.0-0.dll", CallingConvention = CallingConvention.Cdecl)]
static extern uint g_signal_connect_closure (IntPtr instance,
string name, IntPtr closure, bool after);
[DllImport ("gobject-2.0-0.dll", CallingConvention = CallingConvention.Cdecl)]
static extern void g_closure_set_meta_marshal (IntPtr closure, IntPtr data, GClosureMarshal marshal);
class GTypeSignalKey
{
GType type;
string signal_name;
public GTypeSignalKey (GType type, string name)
{
this.type = type;
signal_name = name;
}
public override bool Equals (object o)
{
if (o is GTypeSignalKey) {
GTypeSignalKey k = (GTypeSignalKey)o;
return k.type.Equals (this.type) && signal_name.Equals (k.signal_name);
}
return base.Equals (o);
}
public override int GetHashCode ()
{
return type.GetHashCode () ^ signal_name.GetHashCode ();
}
}
struct SignalQuery
{
public uint signal_id;
public string signal_name;
public GType itype;
public uint signal_flags;
public GType return_type;
public uint n_params;
public Type[] param_types;
}
static Hashtable SignalEmitInfo = new Hashtable ();
public static object Emit (GLib.Object o, string name, params object[] parameters)
{
SignalQuery query;
GType gtype = o.NativeType;
IntPtr type = gtype.Val;
string signal_name, signal_detail;
uint signal_detail_quark = 0;
int colon;
colon = name.LastIndexOf ("::");
if (colon == -1) {
signal_name = name;
signal_detail = String.Empty;
} else {
signal_name = name.Substring (0, colon);
signal_detail = name.Substring (colon + 2);
}
GTypeSignalKey key = new GTypeSignalKey (gtype, signal_name);
if (SignalEmitInfo [key] == null) {
IntPtr native_string = GLib.Marshaller.StringToPtrGStrdup (signal_name);
uint signal_id = g_signal_lookup (native_string, type);
GLib.Marshaller.Free (native_string);
if (signal_id == 0)
throw new NotSupportedException (String.Format ("{0} has no signal of name {1}", o, name));
GSignalQuery q = new GSignalQuery ();
g_signal_query (signal_id, ref q);
if (q.signal_id == 0)
throw new NotSupportedException (String.Format ("{0} couldn't be queried for signal with name {1}", o, name));
query = new SignalQuery ();
query.signal_id = signal_id;
query.signal_name = GLib.Marshaller.Utf8PtrToString (q.signal_name);
query.itype = new GType (q.itype);
query.signal_flags = q.signal_flags;
query.return_type = new GType (q.return_type);
query.n_params = q.n_params;
query.param_types = new Type[q.n_params];
for (int i = 0; i < query.n_params; i++) {
IntPtr t = Marshal.ReadIntPtr (q.param_types, i * IntPtr.Size);
GType g = new GType (t);
query.param_types [i] = (Type)g;
}
SignalEmitInfo.Add (key, query);
}
query = (SignalQuery)SignalEmitInfo [key];
GLib.Value[] signal_parameters = new GLib.Value[query.n_params + 1];
signal_parameters [0] = new GLib.Value (o);
if (parameters.Length != query.n_params)
throw new ApplicationException (String.Format ("Invalid number of parameters: expected {0}, got {1}", query.n_params, parameters.Length));
for (int i = 0; i < query.n_params; i++) {
Type expected_type = (Type)query.param_types [i];
Type given_type = parameters [i].GetType ();
if (expected_type != given_type && !given_type.IsSubclassOf (given_type))
throw new ApplicationException (String.Format ("Invalid parameter type: expected {0}, got {1}", expected_type, given_type));
signal_parameters [i + 1] = new GLib.Value (parameters [i]);
}
GLib.Value return_value = new GLib.Value ();
if (query.return_type != GType.Invalid && query.return_type != GType.None)
return_value.Init (query.return_type);
if (signal_detail != String.Empty) {
IntPtr native_string = GLib.Marshaller.StringToPtrGStrdup (signal_detail);
signal_detail_quark = g_quark_from_string (native_string);
GLib.Marshaller.Free (native_string);
}
g_signal_emitv (signal_parameters, query.signal_id, signal_detail_quark, ref return_value);
foreach (GLib.Value v in signal_parameters)
v.Dispose ();
object ret = (query.return_type != GType.Invalid && query.return_type != GType.None) ? return_value.Val : null;
if (ret != null)
return_value.Dispose ();
return ret;
}
[DllImport ("gobject-2.0-0.dll", CallingConvention = CallingConvention.Cdecl)]
static extern int g_signal_handler_disconnect (IntPtr o, uint handler_id);
[DllImport ("gobject-2.0-0.dll", CallingConvention = CallingConvention.Cdecl)]
static extern uint g_signal_lookup (IntPtr name, IntPtr itype);
[DllImport ("glib-2.0-0.dll", CallingConvention = CallingConvention.Cdecl)]
static extern uint g_quark_from_string (IntPtr str);
[DllImport ("gobject-2.0-0.dll", CallingConvention = CallingConvention.Cdecl)]
static extern void g_signal_emitv (GLib.Value[] parameters, uint signal_id, uint detail, ref GLib.Value return_value);
[StructLayout (LayoutKind.Sequential)]
struct GSignalQuery
{
public uint signal_id;
public IntPtr signal_name;
public IntPtr itype;
public uint signal_flags;
public IntPtr return_type;
public uint n_params;
public IntPtr param_types;
}
[DllImport ("gobject-2.0-0.dll", CallingConvention = CallingConvention.Cdecl)]
static extern void g_signal_query (uint signal_id, ref GSignalQuery query);
}
}