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 {
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 {
uint handlerId;
IntPtr closure;
Delegate registeredHandler;
Type argsType;
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) {
this.handlerId = handlerId;
this.closure = closure;
this.registeredHandler = registeredHandler;
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 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);
}
static int g_closure_sizeof = gstsharp_g_closure_sizeof ();
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");
IntPtr closure = g_closure_new_simple (g_closure_sizeof, IntPtr.Zero);
g_closure_set_meta_marshal (closure, (IntPtr) GCHandle.Alloc (k), marshalHandler);
uint signalId = g_signal_connect_closure (o.Handle, name, closure, after);
SignalHandlers.Add (k, new SignalInfo (signalId, closure, handler));
}
}
[DllImport ("libgstreamersharpglue-1.0.0.dll") ]
static extern int gstsharp_g_closure_sizeof ();
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);
} 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 ("libgobject-2.0-0.dll") ]
static extern IntPtr g_closure_new_simple (int size, IntPtr data);
[DllImport ("libgobject-2.0-0.dll") ]
static extern uint g_signal_connect_closure (IntPtr instance,
string name, IntPtr closure, bool after);
[DllImport ("libgobject-2.0-0.dll") ]
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;
IntPtr type = gstsharp_g_type_from_instance (o.Handle);
GType gtype = new GType (type);
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);
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 ("libgstreamersharpglue-1.0.0.dll") ]
static extern IntPtr gstsharp_g_type_from_instance (IntPtr o);
[DllImport ("libgobject-2.0-0.dll") ]
static extern int g_signal_handler_disconnect (IntPtr o, uint handler_id);
[DllImport ("libgobject-2.0-0.dll") ]
static extern uint g_signal_lookup (IntPtr name, IntPtr itype);
[DllImport ("libglib-2.0-0.dll") ]
static extern uint g_quark_from_string (IntPtr str);
[DllImport ("libgobject-2.0-0.dll") ]
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 ("libgobject-2.0-0.dll") ]
static extern void g_signal_query (uint signal_id, ref GSignalQuery query);
}
}