Files
FlaxEngine/Source/Engine/Core/Delegate.h
2025-06-09 10:17:51 +02:00

850 lines
24 KiB
C++

// Copyright (c) Wojciech Figat. All rights reserved.
#pragma once
// Toggles Delegate implementation type (mutex+hashset or atomic+table)
// [Deprecated on 12.09.2023, expires on 12.09.2024]
#define DELEGATE_USE_ATOMIC 0
#include "Engine/Core/Memory/Allocation.h"
#include "Engine/Core/Collections/HashFunctions.h"
#if !DELEGATE_USE_ATOMIC
#include "Engine/Threading/Threading.h"
#include "Engine/Core/Collections/HashSet.h"
#endif
#if COMPILE_WITH_PROFILER
#include "Engine/Profiler/ProfilerMemory.h"
#endif
/// <summary>
/// The function object that supports binding static, member and lambda functions.
/// </summary>
template<typename ReturnType, typename... Params>
class Function<ReturnType(Params...)>
{
public:
friend Delegate<Params...>;
template<typename... TParams>
friend uint32 GetHash(const Function<void(TParams...)>& key);
/// <summary>
/// Signature of the function to call.
/// </summary>
typedef ReturnType (*Signature)(Params...);
private:
typedef ReturnType (*StubSignature)(void*, Params...);
template<ReturnType(*Method)(Params...)>
static ReturnType StaticMethodStub(void*, Params... params)
{
return (Method)(Forward<Params>(params)...);
}
static ReturnType StaticPointerMethodStub(void* callee, Params... params)
{
return reinterpret_cast<Signature>(callee)(Forward<Params>(params)...);
}
template<class T, ReturnType(T::*Method)(Params...)>
static ReturnType ClassMethodStub(void* callee, Params... params)
{
return (reinterpret_cast<T*>(callee)->*Method)(Forward<Params>(params)...);
}
template<class T, ReturnType(T::*Method)(Params...) const>
static ReturnType ClassMethodStub(void* callee, Params... params)
{
return (reinterpret_cast<T*>(callee)->*Method)(Forward<Params>(params)...);
}
struct Lambda
{
int64 Refs;
void (*Dtor)(void*);
};
void* _callee;
StubSignature _function;
Lambda* _lambda;
FORCE_INLINE void LambdaCtor() const
{
Platform::InterlockedIncrement((int64 volatile*)&_lambda->Refs);
}
FORCE_INLINE void LambdaDtor()
{
if (Platform::InterlockedDecrement(&_lambda->Refs) == 0)
{
((Lambda*)_lambda)->Dtor(_callee);
Allocator::Free(_lambda);
}
}
public:
/// <summary>
/// Initializes a new instance of the <see cref="Function"/> class.
/// </summary>
Function()
{
_callee = nullptr;
_function = nullptr;
_lambda = nullptr;
}
/// <summary>
/// Initializes a new instance of the <see cref="Function"/> class.
/// </summary>
Function(Signature method)
{
_callee = (void*)method;
_function = &StaticPointerMethodStub;
_lambda = nullptr;
}
/// <summary>
/// Initializes a new instance of the <see cref="Function"/> class.
/// </summary>
template<typename T>
Function(const T& lambda)
{
_lambda = nullptr;
Bind<T>(lambda);
}
Function(const Function& other)
: _callee(other._callee)
, _function(other._function)
, _lambda(other._lambda)
{
if (_lambda)
LambdaCtor();
}
Function(Function&& other) noexcept
: _callee(other._callee)
, _function(other._function)
, _lambda(other._lambda)
{
other._lambda = nullptr;
}
~Function()
{
if (_lambda)
LambdaDtor();
}
public:
/// <summary>
/// Binds a static function.
/// </summary>
template<ReturnType(*Method)(Params...)>
void Bind()
{
if (_lambda)
LambdaDtor();
_callee = nullptr;
_function = &StaticMethodStub<Method>;
_lambda = nullptr;
}
/// <summary>
/// Binds a member function.
/// </summary>
/// <param name="callee">The object instance.</param>
template<class T, ReturnType(T::*Method)(Params...)>
void Bind(T* callee)
{
if (_lambda)
LambdaDtor();
_callee = callee;
_function = &ClassMethodStub<T, Method>;
_lambda = nullptr;
}
/// <summary>
/// Binds a function.
/// </summary>
/// <param name="method">The method.</param>
void Bind(Signature method)
{
if (_lambda)
LambdaDtor();
_callee = (void*)method;
_function = &StaticPointerMethodStub;
_lambda = nullptr;
}
/// <summary>
/// Binds a lambda.
/// </summary>
/// <param name="lambda">The lambda.</param>
template<typename T>
void Bind(const T& lambda)
{
if (_lambda)
LambdaDtor();
_lambda = (Lambda*)Allocator::Allocate(sizeof(Lambda) + sizeof(T));
_lambda->Refs = 1;
_lambda->Dtor = [](void* callee) -> void
{
static_cast<T*>(callee)->~T();
};
_function = [](void* callee, Params... params) -> ReturnType
{
return (*static_cast<T*>(callee))(Forward<Params>(params)...);
};
_callee = (byte*)_lambda + sizeof(Lambda);
new(_callee) T(lambda);
}
/// <summary>
/// Unbinds the function.
/// </summary>
void Unbind()
{
if (_lambda)
LambdaDtor();
_callee = nullptr;
_function = nullptr;
_lambda = nullptr;
}
public:
/// <summary>
/// Returns true if any function has been bound.
/// </summary>
FORCE_INLINE bool IsBinded() const
{
return _function != nullptr;
}
/// <summary>
/// Calls the bound function (it must be assigned).
/// </summary>
/// <param name="params">A list of parameters for the function invocation.</param>
/// <returns>Function result</returns>
FORCE_INLINE ReturnType operator()(Params... params) const
{
ASSERT_LOW_LAYER(_function);
return _function(_callee, Forward<Params>(params)...);
}
Function& operator=(const Function& other)
{
if (this == &other)
return *this;
_callee = other._callee;
_function = other._function;
_lambda = other._lambda;
if (_lambda)
LambdaCtor();
return *this;
}
Function& operator=(Function&& other) noexcept
{
if (this == &other)
return *this;
_callee = other._callee;
_function = other._function;
_lambda = other._lambda;
other._callee = nullptr;
other._function = nullptr;
other._lambda = nullptr;
return *this;
}
FORCE_INLINE bool operator==(const Function& other) const
{
return _function == other._function && _callee == other._callee;
}
FORCE_INLINE bool operator!=(const Function& other) const
{
return _function != other._function || _callee != other._callee;
}
};
/// <summary>
/// Delegate object that can be used to bind and call multiply functions. Thread-safe to register/unregister during the call. Execution order of bound functions is not stable.
/// </summary>
template<typename... Params>
class Delegate
{
public:
/// <summary>
/// Signature of the function to call.
/// </summary>
typedef void (*Signature)(Params...);
/// <summary>
/// Template for the function.
/// </summary>
using FunctionType = Function<void(Params...)>;
protected:
#if DELEGATE_USE_ATOMIC
// Single allocation for list of binded functions. Thread-safe access via atomic operations. Removing binded function simply clears the entry to handle function unregister during invocation.
intptr volatile _ptr = 0;
intptr volatile _size = 0;
typedef void (*StubSignature)(void*, Params...);
#else
struct Data
{
HashSet<FunctionType> Functions;
CriticalSection Locker;
};
// Holds pointer to Data with Functions and Locker. Thread-safe access via atomic operations.
intptr volatile _data = 0;
#endif
public:
Delegate()
{
}
Delegate(const Delegate& other)
{
#if DELEGATE_USE_ATOMIC
const intptr newSize = other._size;
auto newBindings = (FunctionType*)Allocator::Allocate(newSize * sizeof(FunctionType));
Platform::MemoryCopy((void*)newBindings, (const void*)other._ptr, newSize * sizeof(FunctionType));
for (intptr i = 0; i < newSize; i++)
{
FunctionType& f = newBindings[i];
if (f._function && f._lambda)
f.LambdaCtor();
}
_ptr = (intptr)newBindings;
_size = newSize;
#else
Data* otherData = (Data*)Platform::AtomicRead(&_data);
if (otherData == nullptr)
return;
ScopeLock lock(otherData->Locker);
for (auto i = otherData->Functions.Begin(); i.IsNotEnd(); ++i)
Bind(i->Item);
#endif
}
Delegate(Delegate&& other) noexcept
{
#if DELEGATE_USE_ATOMIC
_ptr = other._ptr;
_size = other._size;
other._ptr = 0;
other._size = 0;
#else
_data = other._data;
other._data = 0;
#endif
}
~Delegate()
{
#if DELEGATE_USE_ATOMIC
auto ptr = (FunctionType*)_ptr;
if (ptr)
{
while (_size--)
{
if (ptr->_lambda)
ptr->LambdaDtor();
++ptr;
}
Allocator::Free((void*)_ptr);
}
#else
Data* data = (Data*)_data;
if (data)
{
_data = 0;
Delete(data);
}
#endif
}
Delegate& operator=(const Delegate& other)
{
if (this != &other)
{
UnbindAll();
#if DELEGATE_USE_ATOMIC
const intptr size = Platform::AtomicRead((intptr volatile*)&other._size);
FunctionType* bindings = (FunctionType*)Platform::AtomicRead((intptr volatile*)&other._ptr);
for (intptr i = 0; i < size; i++)
Bind(bindings[i]);
#else
Data* otherData = (Data*)Platform::AtomicRead(&_data);
if (otherData != nullptr)
{
ScopeLock lock(otherData->Locker);
for (auto i = otherData->Functions.Begin(); i.IsNotEnd(); ++i)
Bind(i->Item);
}
#endif
}
return *this;
}
Delegate& operator=(Delegate&& other) noexcept
{
if (this != &other)
{
#if DELEGATE_USE_ATOMIC
_ptr = other._ptr;
_size = other._size;
other._ptr = 0;
other._size = 0;
#else
_data = other._data;
other._data = 0;
#endif
}
return *this;
}
public:
/// <summary>
/// Binds a static function.
/// </summary>
template<void(*Method)(Params...)>
void Bind()
{
FunctionType f;
f.template Bind<Method>();
Bind(f);
}
/// <summary>
/// Binds a member function.
/// </summary>
/// <param name="callee">The object instance.</param>
template<class T, void(T::*Method)(Params...)>
void Bind(T* callee)
{
FunctionType f;
f.template Bind<T, Method>(callee);
Bind(f);
}
/// <summary>
/// Binds a function.
/// </summary>
/// <param name="method">The method.</param>
void Bind(Signature method)
{
FunctionType f(method);
Bind(f);
}
/// <summary>
/// Binds a lambda.
/// </summary>
/// <param name="lambda">The lambda.</param>
template<typename T>
void Bind(const T& lambda)
{
FunctionType f;
f.template Bind<T>(lambda);
Bind(f);
}
/// <summary>
/// Binds a function.
/// </summary>
/// <param name="f">The function to bind.</param>
void Bind(const FunctionType& f)
{
#if COMPILE_WITH_PROFILER
PROFILE_MEM(EngineDelegate);
#endif
#if DELEGATE_USE_ATOMIC
const intptr size = Platform::AtomicRead(&_size);
FunctionType* bindings = (FunctionType*)Platform::AtomicRead(&_ptr);
if (bindings)
{
// Find a first free slot
for (intptr i = 0; i < size; i++)
{
if (Platform::InterlockedCompareExchange((intptr volatile*)&bindings[i]._function, (intptr)f._function, 0) == 0)
{
bindings[i]._callee = f._callee;
bindings[i]._lambda = f._lambda;
if (f._lambda)
f.LambdaCtor();
return;
}
}
}
// Failed to find an empty slot in the list (empty or too small) so perform reallocation
const intptr newSize = size ? size * 2 : 32;
auto newBindings = (FunctionType*)Allocator::Allocate(newSize * sizeof(FunctionType));
Platform::MemoryCopy(newBindings, bindings, size * sizeof(FunctionType));
Platform::MemoryClear(newBindings + size, (newSize - size) * sizeof(FunctionType));
// Insert function into a first slot after the old list
newBindings[size] = f;
// Set the new list
auto oldBindings = (FunctionType*)Platform::InterlockedCompareExchange(&_ptr, (intptr)newBindings, (intptr)bindings);
if (oldBindings != bindings)
{
// Other thread already set the new list so free this list and try again
Allocator::Free(newBindings);
Bind(f);
}
else
{
// Free previous bindings and update list size
Platform::AtomicStore(&_size, newSize);
// TODO: what is someone read this value before and is using the old table?
Allocator::Free(bindings);
}
#else
Data* data = (Data*)Platform::AtomicRead(&_data);
while (!data)
{
Data* newData = New<Data>();
Data* oldData = (Data*)Platform::InterlockedCompareExchange(&_data, (intptr)newData, (intptr)data);
if (oldData != data)
{
// Other thread already set the new data so free it and try again
Delete(newData);
}
data = (Data*)Platform::AtomicRead(&_data);
}
ScopeLock lock(data->Locker);
data->Functions.Add(f);
#endif
}
/// <summary>
/// Binds a static function (if not bound yet).
/// </summary>
template<void(*Method)(Params...)>
void BindUnique()
{
FunctionType f;
f.template Bind<Method>();
BindUnique(f);
}
/// <summary>
/// Binds a member function (if not bound yet).
/// </summary>
/// <param name="callee">The object instance.</param>
template<class T, void(T::*Method)(Params...)>
void BindUnique(T* callee)
{
FunctionType f;
f.template Bind<T, Method>(callee);
BindUnique(f);
}
/// <summary>
/// Binds a function (if not bound yet).
/// </summary>
/// <param name="method">The method.</param>
void BindUnique(Signature method)
{
FunctionType f(method);
BindUnique(f);
}
/// <summary>
/// Binds a function (if not bound yet).
/// </summary>
/// <param name="f">The function to bind.</param>
void BindUnique(const FunctionType& f)
{
// Skip if already bound
#if DELEGATE_USE_ATOMIC
const intptr size = Platform::AtomicRead(&_size);
FunctionType* bindings = (FunctionType*)Platform::AtomicRead(&_ptr);
if (bindings)
{
for (intptr i = 0; i < size; i++)
{
if (Platform::AtomicRead((intptr volatile*)&bindings[i]._callee) == (intptr)f._callee && Platform::AtomicRead((intptr volatile*)&bindings[i]._function) == (intptr)f._function)
return;
}
}
#else
Data* data = (Data*)Platform::AtomicRead(&_data);
if (data)
{
data->Locker.Lock();
if (data->Functions.Contains(f))
{
data->Locker.Unlock();
return;
}
}
#endif
Bind(f);
#if !DELEGATE_USE_ATOMIC
if (data)
data->Locker.Unlock();
#endif
}
/// <summary>
/// Unbinds a static function.
/// </summary>
template<void(*Method)(Params...)>
void Unbind()
{
FunctionType f;
f.template Bind<Method>();
Unbind(f);
}
/// <summary>
/// Unbinds a member function.
/// </summary>
/// <param name="callee">The object instance.</param>
template<class T, void(T::*Method)(Params...)>
void Unbind(T* callee)
{
FunctionType f;
f.template Bind<T, Method>(callee);
Unbind(f);
}
/// <summary>
/// Unbinds the specified function.
/// </summary>
/// <param name="method">The method.</param>
void Unbind(Signature method)
{
FunctionType f(method);
Unbind(f);
}
/// <summary>
/// Unbinds the specified function.
/// </summary>
/// <param name="f">The function to unbind.</param>
void Unbind(const FunctionType& f)
{
#if DELEGATE_USE_ATOMIC
// Find slot with that function
const intptr size = Platform::AtomicRead(&_size);
FunctionType* bindings = (FunctionType*)Platform::AtomicRead(&_ptr);
for (intptr i = 0; i < size; i++)
{
if (Platform::AtomicRead((intptr volatile*)&bindings[i]._callee) == (intptr)f._callee && Platform::AtomicRead((intptr volatile*)&bindings[i]._function) == (intptr)f._function)
{
if (bindings[i]._lambda)
{
bindings[i].LambdaDtor();
bindings[i]._lambda = nullptr;
}
Platform::AtomicStore((intptr volatile*)&bindings[i]._callee, 0);
Platform::AtomicStore((intptr volatile*)&bindings[i]._function, 0);
break;
}
}
if ((FunctionType*)Platform::AtomicRead(&_ptr) != bindings)
{
// Someone changed the bindings list so retry unbind from the new one
Unbind(f);
}
#else
Data* data = (Data*)Platform::AtomicRead(&_data);
if (!data)
return;
ScopeLock lock(data->Locker);
data->Functions.Remove(f);
#endif
}
/// <summary>
/// Unbinds all the functions.
/// </summary>
void UnbindAll()
{
#if DELEGATE_USE_ATOMIC
const intptr size = Platform::AtomicRead(&_size);
FunctionType* bindings = (FunctionType*)Platform::AtomicRead(&_ptr);
for (intptr i = 0; i < size; i++)
{
if (bindings[i]._lambda)
{
bindings[i].LambdaDtor();
bindings[i]._lambda = nullptr;
}
Platform::AtomicStore((intptr volatile*)&bindings[i]._function, 0);
Platform::AtomicStore((intptr volatile*)&bindings[i]._callee, 0);
}
#else
Data* data = (Data*)Platform::AtomicRead(&_data);
if (!data)
return;
ScopeLock lock(data->Locker);
data->Functions.Clear();
#endif
}
/// <summary>
/// Counts the amount of bound functions.
/// </summary>
/// <returns>The bound functions count.</returns>
int32 Count() const
{
int32 result = 0;
#if DELEGATE_USE_ATOMIC
const intptr size = Platform::AtomicRead((intptr volatile*)&_size);
FunctionType* bindings = (FunctionType*)Platform::AtomicRead((intptr volatile*)&_ptr);
for (intptr i = 0; i < size; i++)
{
if (Platform::AtomicRead((intptr volatile*)&bindings[i]._function) != 0)
result++;
}
#else
Data* data = (Data*)Platform::AtomicRead((intptr volatile*)&_data);
if (data)
{
ScopeLock lock(data->Locker);
result = data->Functions.Count();
}
#endif
return result;
}
/// <summary>
/// Gets the current capacity of delegate table (amount of function to store before resizing).
/// </summary>
int32 Capacity() const
{
#if DELEGATE_USE_ATOMIC
return (int32)Platform::AtomicRead((intptr volatile*)&_size);
#else
int32 result = 0;
Data* data = (Data*)Platform::AtomicRead((intptr volatile*)&_data);
if (data)
{
ScopeLock lock(data->Locker);
result = data->Functions.Capacity();
}
return result;
#endif
}
/// <summary>
/// Determines whether any function is bound.
/// </summary>
/// <returns><c>true</c> if any function is bound; otherwise, <c>false</c>.</returns>
bool IsBinded() const
{
#if DELEGATE_USE_ATOMIC
const intptr size = Platform::AtomicRead((intptr volatile*)&_size);
FunctionType* bindings = (FunctionType*)Platform::AtomicRead((intptr volatile*)&_ptr);
for (intptr i = 0; i < size; i++)
{
if (Platform::AtomicRead((intptr volatile*)&bindings[i]._function) != 0)
return true;
}
return false;
#else
bool result = false;
Data* data = (Data*)Platform::AtomicRead((intptr volatile*)&_data);
if (data)
{
ScopeLock lock(data->Locker);
result = data->Functions.Count() != 0;
}
return result;
#endif
}
/// <summary>
/// Gets all the bound functions.
/// </summary>
/// <param name="buffer">The result bindings functions memory.</param>
/// <param name="bufferSize">The result bindings functions memory size.</param>
/// <returns>The amount of written items into the output bindings buffer. Can be equal or less than input bindingsCount capacity.</returns>
int32 GetBindings(FunctionType* buffer, int32 bufferSize) const
{
int32 count = 0;
#if DELEGATE_USE_ATOMIC
const intptr size = Platform::AtomicRead((intptr volatile*)&_size);
FunctionType* bindings = (FunctionType*)Platform::AtomicRead((intptr volatile*)&_ptr);
for (intptr i = 0; i < size && i < bufferSize; i++)
{
buffer[count]._function = (StubSignature)Platform::AtomicRead((intptr volatile*)&bindings[i]._function);
if (buffer[count]._function != nullptr)
{
buffer[count]._callee = (void*)Platform::AtomicRead((intptr volatile*)&bindings[i]._callee);
buffer[count]._lambda = (typename FunctionType::Lambda*)Platform::AtomicRead((intptr volatile*)&bindings[i]._lambda);
if (buffer[count]._lambda)
buffer[count].LambdaCtor();
count++;
}
}
#else
Data* data = (Data*)Platform::AtomicRead((intptr volatile*)&_data);
if (data)
{
ScopeLock lock(data->Locker);
for (auto i = data->Functions.Begin(); i.IsNotEnd(); ++i)
{
new(buffer + count) FunctionType((const FunctionType&)i->Item);
count++;
}
}
#endif
return count;
}
/// <summary>
/// Calls all the bound functions. Supports unbinding of the called functions during invocation.
/// </summary>
/// <param name="params">A list of parameters for the function invocation.</param>
void operator()(Params... params) const
{
#if DELEGATE_USE_ATOMIC
const intptr size = Platform::AtomicRead((intptr volatile*)&_size);
FunctionType* bindings = (FunctionType*)Platform::AtomicRead((intptr volatile*)&_ptr);
for (intptr i = 0; i < size; i++)
{
auto function = (StubSignature)Platform::AtomicRead((intptr volatile*)&bindings->_function);
auto callee = (void*)Platform::AtomicRead((intptr volatile*)&bindings->_callee);
if (function != nullptr && function == (StubSignature)Platform::AtomicRead((intptr volatile*)&bindings->_function))
function(callee, params...);
++bindings;
}
#else
Data* data = (Data*)Platform::AtomicRead((intptr volatile*)&_data);
if (!data)
return;
ScopeLock lock(data->Locker);
for (auto i = data->Functions.Begin(); i.IsNotEnd(); ++i)
{
const FunctionType& item = i->Item;
ASSERT_LOW_LAYER(item._function);
item._function(item._callee, params...);
}
#endif
}
};
template<typename... Params>
inline uint32 GetHash(const Function<void(Params...)>& key)
{
uint32 hash = GetHash((void*)key._callee);
CombineHash(hash, GetHash((void*)key._function));
return hash;
}
/// <summary>
/// Action delegate.
/// </summary>
typedef Delegate<> Action;