public const string __doc__ = "Provides support for creating weak references and proxies to objects";

/// <summary>

/// Wrapper provided for backwards compatibility.

/// </summary>

internal static IWeakReferenceable ConvertToWeakReferenceable(PythonContext context, object obj) {

return context.ConvertToWeakReferenceable(obj);

}

public static int getweakrefcount(CodeContext context, object @object) {

return @ref.GetWeakRefCount(context.LanguageContext, @object);

}

public static PythonList getweakrefs(CodeContext context, object @object) {

return @ref.GetWeakRefs(context.LanguageContext, @object);

}

public static object proxy(CodeContext context, object @object) {

return proxy(context, @object, null);

}

public static object proxy(CodeContext context, object @object, object callback) {

if (PythonOps.IsCallable(context, @object)) {

return weakcallableproxy.MakeNew(context, @object, callback);

} else {

return weakproxy.MakeNew(context, @object, callback);

}

}

// new in CPython 3.5

public static void _remove_dead_weakref(CodeContext context, PythonDictionary dict, object key) {

if (dict.TryGetValue(key, out var value)) {

if (value is @ref r) {

if (r._target.Target is null) {

dict.Remove(key);

}

} else if (value is weakproxy wp) {

if (wp._target.Target is null) {

dict.Remove(key);

}

} else if (value is weakcallableproxy wcp) {

if (wcp._target.Target is null) {

dict.Remove(key);

}

}

}

}

[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Security", "CA2104:DoNotDeclareReadOnlyMutableReferenceTypes")]

public static readonly PythonType CallableProxyType = DynamicHelpers.GetPythonTypeFromType(typeof(weakcallableproxy));

[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Security", "CA2104:DoNotDeclareReadOnlyMutableReferenceTypes")]

public static readonly PythonType ProxyType = DynamicHelpers.GetPythonTypeFromType(typeof(weakproxy));

[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Security", "CA2104:DoNotDeclareReadOnlyMutableReferenceTypes")]

public static readonly PythonType ReferenceType = DynamicHelpers.GetPythonTypeFromType(typeof(@ref));

[PythonType("weakref")]

public class @ref : IStructuralEquatable

{

private readonly CodeContext _context;

internal readonly WeakHandle _target;

private int _hashVal;

private bool _fHasHash;

#region Python Constructors

public static object __new__(CodeContext context, PythonType cls, object @object) {

IWeakReferenceable iwr = ConvertToWeakReferenceable(context.LanguageContext, @object);

if (cls == DynamicHelpers.GetPythonTypeFromType(typeof(@ref))) {

WeakRefTracker wrt = iwr.GetWeakRef();

if (wrt != null) {

for (int i = 0; i < wrt.HandlerCount; i++) {

if (wrt.GetHandlerCallback(i) == null && wrt.GetWeakRef(i) is @ref) {

return wrt.GetWeakRef(i);

}

}

}

return new @ref(context, @object);

} else {

return cls.CreateInstance(context, @object);

}

}

public static object __new__(CodeContext context, PythonType cls, object @object, object callback) {

if (callback == null) return __new__(context, cls, @object);

if (cls == DynamicHelpers.GetPythonTypeFromType(typeof(@ref))) {

return new @ref(context, @object, callback);

} else {

return cls.CreateInstance(context, @object, callback);

}

}

public void __init__(CodeContext context, object ob, object callback = null) { }

#endregion

#region Constructors

public @ref(CodeContext context, object target, object callback = null) {

WeakRefHelpers.InitializeWeakRef(context.LanguageContext, this, target, callback);

_target = new WeakHandle(target, false);

_context = context;

__callback__ = callback;

}

#endregion

#region Finalizer

~@ref() {

if (_context != null && _context.LanguageContext.TryConvertToWeakReferenceable(_target.Target, out IWeakReferenceable iwr)) {

// weak reference being finalized before target object,

// we don't want to run the callback when the object is

// finalized.

iwr.GetWeakRef()?.RemoveHandler(this);

}

_target.Free();

}

#endregion

#region Static helpers

internal static int GetWeakRefCount(PythonContext context, object o) {

IWeakReferenceable iwr;

if (context.TryConvertToWeakReferenceable(o, out iwr)) {

WeakRefTracker wrt = iwr.GetWeakRef();

if (wrt != null) return wrt.HandlerCount;

}

return 0;

}

internal static PythonList GetWeakRefs(PythonContext context, object o) {

PythonList l = new PythonList();

IWeakReferenceable iwr;

if (context.TryConvertToWeakReferenceable(o, out iwr)) {

WeakRefTracker wrt = iwr.GetWeakRef();

if (wrt != null) {

for (int i = 0; i < wrt.HandlerCount; i++) {

l.AddNoLock(wrt.GetWeakRef(i));

}

}

}

return l;

}

#endregion

[SpecialName]

public object Call(CodeContext context) {

object res = _target.Target;

GC.KeepAlive(this);

return res;

}

public object __callback__ { get; }

[return: MaybeNotImplemented]

public static NotImplementedType operator >(@ref self, object other) {

return NotImplementedType.Value;

}

[return: MaybeNotImplemented]

public static NotImplementedType operator <(@ref self, object other) {

return NotImplementedType.Value;

}

[return: MaybeNotImplemented]

public static NotImplementedType operator <=(@ref self, object other) {

return NotImplementedType.Value;

}

[return: MaybeNotImplemented]

public static NotImplementedType operator >=(@ref self, object other) {

return NotImplementedType.Value;

}

#region IStructuralEquatable Members

/// <summary>

/// Special hash function because IStructuralEquatable.GetHashCode is not allowed to throw.

/// </summary>

public int __hash__(CodeContext/*!*/ context) {

if (!_fHasHash) {

object refObj = _target.Target;

if (refObj == null) throw PythonOps.TypeError("weak object has gone away");

_hashVal = context.LanguageContext.EqualityComparerNonGeneric.GetHashCode(refObj);

_fHasHash = true;

}

GC.KeepAlive(this);

return _hashVal;

}

int IStructuralEquatable.GetHashCode(IEqualityComparer comparer) {

if (!_fHasHash) {

object refObj = _target.Target;

_hashVal = comparer.GetHashCode(refObj);

_fHasHash = true;

}

GC.KeepAlive(this);

return _hashVal;

}

bool IStructuralEquatable.Equals(object other, IEqualityComparer comparer) {

return EqualsWorker(other, comparer);

}

private bool EqualsWorker(object other, IEqualityComparer comparer) {

if (object.ReferenceEquals(this, other)) {

return true;

}

bool fResult = false;

@ref wr = other as @ref;

if (wr != null) {

object ourTarget = _target.Target;

object itsTarget = wr._target.Target;

if (ourTarget != null && itsTarget != null) {

fResult = RefEquals(ourTarget, itsTarget, comparer);

}

}

GC.KeepAlive(this);

return fResult;

}

/// <summary>

/// Special equals because none of the special cases in Ops.Equals

/// are applicable here, and the reference equality check breaks some tests.

/// </summary>

private static bool RefEquals(object x, object y, IEqualityComparer comparer) {

CodeContext context;

if (comparer != null && comparer is PythonContext.PythonEqualityComparer) {

context = ((PythonContext.PythonEqualityComparer)comparer).Context.SharedContext;

} else {

context = DefaultContext.Default;

}

object ret;

if (PythonTypeOps.TryInvokeBinaryOperator(context, x, y, "__eq__", out ret) &&

ret != NotImplementedType.Value) {

return (bool)ret;

}

if (PythonTypeOps.TryInvokeBinaryOperator(context, y, x, "__eq__", out ret) &&

ret != NotImplementedType.Value) {

return (bool)ret;

}

if (comparer != null) {

return comparer.Equals(x, y);

}

return x.Equals(y);

}

#endregion

}

[PythonType, DynamicBaseType, PythonHidden]

public sealed partial class weakproxy : IPythonObject, ICodeFormattable, IProxyObject, IPythonMembersList, IStructuralEquatable

{

internal readonly WeakHandle _target;

private readonly CodeContext/*!*/ _context;

#region Python Constructors

internal static object MakeNew(CodeContext/*!*/ context, object @object, object callback) {

IWeakReferenceable iwr = ConvertToWeakReferenceable(context.LanguageContext, @object);

if (callback == null) {

WeakRefTracker wrt = iwr.GetWeakRef();

if (wrt != null) {

for (int i = 0; i < wrt.HandlerCount; i++) {

if (wrt.GetHandlerCallback(i) == null && wrt.GetWeakRef(i) is weakproxy) {

return wrt.GetWeakRef(i);

}

}

}

}

return new weakproxy(context, @object, callback);

}

#endregion

#region Constructors

private weakproxy(CodeContext/*!*/ context, object target, object callback) {

WeakRefHelpers.InitializeWeakRef(context.LanguageContext, this, target, callback);

_target = new WeakHandle(target, false);

_context = context;

}

#endregion

#region Finalizer

~weakproxy() {

// remove our self from the chain...

IWeakReferenceable iwr;

if (_context.LanguageContext.TryConvertToWeakReferenceable(_target.Target, out iwr)) {

WeakRefTracker wrt = iwr.GetWeakRef();

wrt.RemoveHandler(this);

}

_target.Free();

}

#endregion

#region private members

/// <summary>

/// gets the object or throws a reference exception

/// </summary>

private object GetObject() {

object res;

if (!TryGetObject(out res)) {

throw PythonOps.ReferenceError("weakly referenced object no longer exists");

}

return res;

}

private bool TryGetObject(out object result) {

result = _target.Target;

if (result == null) return false;

GC.KeepAlive(this);

return true;

}

#endregion

#region IPythonObject Members

PythonDictionary IPythonObject.Dict {

get {

IPythonObject sdo = GetObject() as IPythonObject;

if (sdo != null) {

return sdo.Dict;

}

return null;

}

}

PythonDictionary IPythonObject.SetDict(PythonDictionary dict) {

return (GetObject() as IPythonObject).SetDict(dict);

}

bool IPythonObject.ReplaceDict(PythonDictionary dict) {

return (GetObject() as IPythonObject).ReplaceDict(dict);

}

void IPythonObject.SetPythonType(PythonType newType) {

(GetObject() as IPythonObject).SetPythonType(newType);

}

PythonType IPythonObject.PythonType {

get {

return DynamicHelpers.GetPythonTypeFromType(typeof(weakproxy));

}

}

object[] IPythonObject.GetSlots() { return null; }

object[] IPythonObject.GetSlotsCreate() { return null; }

#endregion

#region object overloads

public override string ToString() {

return PythonOps.ToString(GetObject());

}

#endregion

#region ICodeFormattable Members

public string/*!*/ __repr__(CodeContext/*!*/ context) {

object obj = _target.Target;

GC.KeepAlive(this);

return String.Format("<weakproxy at {0} to {1} at {2}>",

IdDispenser.GetId(this),

PythonOps.GetPythonTypeName(obj),

IdDispenser.GetId(obj));

}

#endregion

#region Custom member access

[SpecialName]

public object GetCustomMember(CodeContext/*!*/ context, string name) {

object value, o = GetObject();

if (PythonOps.TryGetBoundAttr(context, o, name, out value)) {

return value;

}

return OperationFailed.Value;

}

[SpecialName]

public void SetMember(CodeContext/*!*/ context, string name, object value) {

object o = GetObject();

PythonOps.SetAttr(context, o, name, value);

}

[SpecialName]

public void DeleteMember(CodeContext/*!*/ context, string name) {

object o = GetObject();

PythonOps.DeleteAttr(context, o, name);

}

IList<string> IMembersList.GetMemberNames() {

return PythonOps.GetStringMemberList(this);

}

IList<object> IPythonMembersList.GetMemberNames(CodeContext/*!*/ context) {

object o;

if (!TryGetObject(out o)) {

// if we've been disconnected return an empty list

return new PythonList();

}

return PythonOps.GetAttrNames(context, o);

}

#endregion

#region IProxyObject Members

object IProxyObject.Target {

get { return GetObject(); }

}

#endregion

#region IStructuralEquatable Members

public const object __hash__ = null;

int IStructuralEquatable.GetHashCode(IEqualityComparer comparer) {

object obj;

if (TryGetObject(out obj)) {

return comparer.GetHashCode(obj);

}

return comparer.GetHashCode(null);

}

bool IStructuralEquatable.Equals(object other, IEqualityComparer comparer) {

object obj;

if (!TryGetObject(out obj)) {

obj = null;

}

weakproxy wrp = other as weakproxy;

if (wrp != null) {

object otherObj;

if (!TryGetObject(out otherObj)) {

otherObj = null;

}

return comparer.Equals(obj, otherObj);

}

return comparer.Equals(obj, other);

}

#endregion

public object __bool__() {

return Converter.ConvertToBoolean(GetObject());

}

public static explicit operator bool(weakproxy self) {

return Converter.ConvertToBoolean(self.GetObject());

}

}

[PythonType, DynamicBaseTypeAttribute, PythonHidden]

public sealed partial class weakcallableproxy :

IPythonObject,

ICodeFormattable,

IProxyObject,

IStructuralEquatable,

IPythonMembersList {

internal readonly WeakHandle _target;

private readonly CodeContext/*!*/ _context;

#region Python Constructors

internal static object MakeNew(CodeContext/*!*/ context, object @object, object callback) {

IWeakReferenceable iwr = ConvertToWeakReferenceable(context.LanguageContext, @object);

if (callback == null) {

WeakRefTracker wrt = iwr.GetWeakRef();

if (wrt != null) {

for (int i = 0; i < wrt.HandlerCount; i++) {

if (wrt.GetHandlerCallback(i) == null &&

wrt.GetWeakRef(i) is weakcallableproxy) {

return wrt.GetWeakRef(i);

}

}

}

}

return new weakcallableproxy(context, @object, callback);

}

#endregion

#region Constructors

private weakcallableproxy(CodeContext context, object target, object callback) {

WeakRefHelpers.InitializeWeakRef(context.LanguageContext, this, target, callback);

_target = new WeakHandle(target, false);

_context = context;

}

#endregion

#region Finalizer

~weakcallableproxy() {

// remove our self from the chain...

IWeakReferenceable iwr;

if (_context.LanguageContext.TryConvertToWeakReferenceable(_target.Target, out iwr))

{

WeakRefTracker wrt = iwr.GetWeakRef();

wrt.RemoveHandler(this);

}

_target.Free();

}

#endregion

#region private members

/// <summary>

/// gets the object or throws a reference exception

/// </summary>

private object GetObject() {

object res;

if (!TryGetObject(out res)) {

throw PythonOps.ReferenceError("weakly referenced object no longer exists");

}

return res;

}

private bool TryGetObject(out object result) {

try {

result = _target.Target;

if (result == null) return false;

GC.KeepAlive(this);

return true;

} catch (InvalidOperationException) {

result = null;

return false;

}

}

#endregion

#region IPythonObject Members

PythonDictionary IPythonObject.Dict {

get {

return (GetObject() as IPythonObject).Dict;

}

}

PythonDictionary IPythonObject.SetDict(PythonDictionary dict) {

return (GetObject() as IPythonObject).SetDict(dict);

}

bool IPythonObject.ReplaceDict(PythonDictionary dict) {

return (GetObject() as IPythonObject).ReplaceDict(dict);

}

void IPythonObject.SetPythonType(PythonType newType) {

(GetObject() as IPythonObject).SetPythonType(newType);

}

PythonType IPythonObject.PythonType {

get {

return DynamicHelpers.GetPythonTypeFromType(typeof(weakcallableproxy));

}

}

object[] IPythonObject.GetSlots() { return null; }

object[] IPythonObject.GetSlotsCreate() { return null; }

#endregion

#region object overloads

public override string ToString() {

return PythonOps.ToString(GetObject());

}

#endregion

#region ICodeFormattable Members

public string/*!*/ __repr__(CodeContext/*!*/ context) {

object obj = _target.Target;

GC.KeepAlive(this);

return String.Format("<weakproxy at {0} to {1} at {2}>",

IdDispenser.GetId(this),

PythonOps.GetPythonTypeName(obj),

IdDispenser.GetId(obj));

}

#endregion

[SpecialName]

public object Call(CodeContext/*!*/ context, params object[] args) {

return context.LanguageContext.CallSplat(GetObject(), args);

}

[SpecialName]

public object Call(CodeContext/*!*/ context, [ParamDictionary]IDictionary<object, object> dict, params object[] args) {

return PythonCalls.CallWithKeywordArgs(context, GetObject(), args, dict);

}

#region Custom members access

[SpecialName]

public object GetCustomMember(CodeContext/*!*/ context, string name) {

object o = GetObject();

object value;

if (PythonOps.TryGetBoundAttr(context, o, name, out value)) {

return value;

}

return OperationFailed.Value;

}

[SpecialName]

public void SetMember(CodeContext/*!*/ context, string name, object value) {

object o = GetObject();

PythonOps.SetAttr(context, o, name, value);

}

[SpecialName]

public void DeleteMember(CodeContext/*!*/ context, string name) {

object o = GetObject();

PythonOps.DeleteAttr(context, o, name);

}

IList<string> IMembersList.GetMemberNames() {

return PythonOps.GetStringMemberList(this);

}

IList<object> IPythonMembersList.GetMemberNames(CodeContext/*!*/ context) {

object o;

if (!TryGetObject(out o)) {

// if we've been disconnected return an empty list

return new PythonList();

}

return PythonOps.GetAttrNames(context, o);

}

#endregion

#region IProxyObject Members

object IProxyObject.Target {

get { return GetObject(); }

}

#endregion

#region IStructuralEquatable Members

public const object __hash__ = null;

int IStructuralEquatable.GetHashCode(IEqualityComparer comparer) {

object obj;

if (TryGetObject(out obj)) {

return comparer.GetHashCode(obj);

}

return comparer.GetHashCode(null);

}

bool IStructuralEquatable.Equals(object other, IEqualityComparer comparer) {

object obj;

if (!TryGetObject(out obj)) {

obj = null;

}

weakcallableproxy wrp = other as weakcallableproxy;

if (wrp != null) {

object otherObj;

if (!TryGetObject(out otherObj)) {

otherObj = null;

}

return comparer.Equals(obj, otherObj);

}

return comparer.Equals(obj, other);

}

#endregion

public object __bool__() {

return Converter.ConvertToBoolean(GetObject());

}

}

private static class WeakRefHelpers {

public static WeakRefTracker InitializeWeakRef(PythonContext context, object self, object target, object callback) {

IWeakReferenceable iwr = ConvertToWeakReferenceable(context, target);

WeakRefTracker wrt = iwr.GetWeakRef();

if (wrt == null) {

if (!iwr.SetWeakRef(wrt = new WeakRefTracker(iwr)))

throw PythonOps.TypeError("cannot create weak reference to '{0}' object", PythonOps.GetPythonTypeName(target));

}

if (callback != null || !wrt.Contains(callback, self)) {

wrt.ChainCallback(callback, self);

}

return wrt;

}

}

private readonly string _name;

private readonly PythonType _type;

public SlotWrapper(string slotName, PythonType targetType) {

_name = slotName;

_type = targetType;

}

#region ICodeFormattable Members

public virtual string/*!*/ __repr__(CodeContext/*!*/ context) {

return String.Format("<slot wrapper {0} of {1} objects>",

PythonOps.Repr(context, _name),

PythonOps.Repr(context, _type.Name));

}

#endregion

#region PythonTypeSlot Overrides

internal override bool TryGetValue(CodeContext context, object instance, PythonType owner, out object value) {

if (instance == null) {

value = this;

return true;

}

IProxyObject proxy = instance as IProxyObject;

if (proxy == null)

throw PythonOps.TypeError("descriptor for {0} object doesn't apply to {1} object",

PythonOps.Repr(context, _type.Name),

PythonOps.Repr(context, PythonOps.GetPythonTypeName(instance)));

if (!DynamicHelpers.GetPythonType(proxy.Target).TryGetBoundMember(context, proxy.Target, _name, out value))

return false;

value = new GenericMethodWrapper(_name, proxy);

return true;

}

#endregion

private readonly string name;

private readonly IProxyObject target;

public GenericMethodWrapper(string methodName, IProxyObject proxyTarget) {

name = methodName;

target = proxyTarget;

}

[SpecialName]

public object Call(CodeContext context, params object[] args) {

return PythonOps.Invoke(context, target.Target, name, args);

}

[SpecialName]

public object Call(CodeContext context, [ParamDictionary]IDictionary<object, object> dict, params object[] args) {

object targetMethod;

if (!DynamicHelpers.GetPythonType(target.Target).TryGetBoundMember(context, target.Target, name, out targetMethod))

throw PythonOps.AttributeError("type {0} has no attribute {1}",

DynamicHelpers.GetPythonType(target.Target),

name);

return PythonCalls.CallWithKeywordArgs(context, targetMethod, args, dict);

}