pythonnet/src/runtime/EventHandlerCollection.cs at fix-enum-codec · faizalski/pythonnet · GitHub

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using System;

using System.Collections.Generic;

using System.Reflection;

using System.Runtime.Serialization;

using System.Security.Permissions;

namespace Python.Runtime;

[Serializable]

internal class EventHandlerCollection: Dictionary<object, List<Handler>>

{

readonly EventInfo info;

public EventHandlerCollection(EventInfo @event)

{

info = @event;

}

/// <summary>

/// Register a new Python object event handler with the event.

/// </summary>

internal bool AddEventHandler(BorrowedReference target, PyObject handler)

{

object? obj = null;

if (target != null)

{

var co = (CLRObject)ManagedType.GetManagedObject(target)!;

obj = co.inst;

}

// Create a true delegate instance of the appropriate type to

// wrap the Python handler. Note that wrapper delegate creation

// always succeeds, though calling the wrapper may fail.

Type type = info.EventHandlerType;

Delegate d = PythonEngine.DelegateManager.GetDelegate(type, handler);

// Now register the handler in a mapping from instance to pairs

// of (handler hash, delegate) so we can lookup to remove later.

object key = obj ?? info.ReflectedType;

if (!TryGetValue(key, out var list))

{

list = new List<Handler>();

this[key] = list;

}

list.Add(new Handler(Runtime.PyObject_Hash(handler), d));

// Note that AddEventHandler helper only works for public events,

// so we have to get the underlying add method explicitly.

object[] args = { d };

MethodInfo mi = info.GetAddMethod(true);

mi.Invoke(obj, BindingFlags.Default, null, args, null);

return true;

}

/// <summary>

/// Remove the given Python object event handler.

/// </summary>

internal bool RemoveEventHandler(BorrowedReference target, BorrowedReference handler)

{

object? obj = null;

if (target != null)

{

var co = (CLRObject)ManagedType.GetManagedObject(target)!;

obj = co.inst;

}

nint hash = Runtime.PyObject_Hash(handler);

if (hash == -1 && Exceptions.ErrorOccurred())

{

return false;

}

object key = obj ?? info.ReflectedType;

if (!TryGetValue(key, out var list))

{

Exceptions.SetError(Exceptions.ValueError, "unknown event handler");

return false;

}

object?[] args = { null };

MethodInfo mi = info.GetRemoveMethod(true);

for (var i = 0; i < list.Count; i++)

{

var item = (Handler)list[i];

if (item.hash != hash)

{

continue;

}

args[0] = item.del;

try

{

mi.Invoke(obj, BindingFlags.Default, null, args, null);

}

catch

{

continue;

}

list.RemoveAt(i);

return true;

}

Exceptions.SetError(Exceptions.ValueError, "unknown event handler");

return false;

}

#region Serializable

[SecurityPermission(SecurityAction.Demand, SerializationFormatter = true)]

protected EventHandlerCollection(SerializationInfo info, StreamingContext context)

: base(info, context)

{

this.info = (EventInfo)info.GetValue("event", typeof(EventInfo));

}

[SecurityPermission(SecurityAction.Demand, SerializationFormatter = true)]

public override void GetObjectData(SerializationInfo info, StreamingContext context)

{

base.GetObjectData(info, context);

info.AddValue("event", this.info);

}

#endregion

}

pythonnet/src/runtime/EventHandlerCollection.cs at fix-enum-codec · faizalski/pythonnet · GitHub

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