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https://github.com/rive-app/rive-cpp.git
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c719ce1cc4
Made lite rtti now use compile time hashes that use the name of the class with rtti enabled as the hash string. Every use of rtti now needs to be a macro. but other then that, usage of lite rtti is unchanged. Diffs= 2be44a0f45 Deterministic lite rtti (#8349) Co-authored-by: Jonathon Copeland <jcopela4@gmail.com>
94 lines
3.1 KiB
C++
94 lines
3.1 KiB
C++
/*
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* Copyright 2023 Rive
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*/
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// "lite_rtti_cast<T*>()" is a very basic polyfill for "dynamic_cast<T*>()" that
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// can only cast a pointer to its most-derived type. To use it, the base class
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// must derive from enable_lite_rtti, and the subclass must inherit from
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// lite_rtti_override:
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//
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// class Root : public enable_lite_rtti<Root> {};
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// class Derived : public lite_rtti_override<Root, Derived> {};
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// Root* derived = new Derived();
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// lite_rtti_cast<Derived*>(derived);
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//
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#pragma once
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#include "utils/compile_time_string_hash.hpp"
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#include "rive/refcnt.hpp"
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#include <stdint.h>
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#include <type_traits>
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namespace rive
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{
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// Enable lite rtti on the root of a class hierarchy.
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template <class Root, unsigned int ID> class enable_lite_rtti
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{
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public:
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unsigned int liteTypeID() const { return m_liteTypeId; }
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protected:
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unsigned int m_liteTypeId = ID;
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};
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// Override the lite rtti type ID on subsequent classes of a class hierarchy.
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template <class Base, class Derived, unsigned int ID>
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class lite_rtti_override : public Base
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{
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public:
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constexpr static uint32_t LITE_RTTI_TYPE_ID = ID;
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lite_rtti_override() { Base::m_liteTypeId = ID; }
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template <typename... Args>
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lite_rtti_override(Args&&... args) : Base(std::forward<Args>(args)...)
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{
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Base::m_liteTypeId = ID;
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}
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};
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// Like dynamic_cast<>, but can only cast a pointer to its most-derived type.
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template <class U, class T> U lite_rtti_cast(T* t)
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{
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if (t != nullptr &&
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t->liteTypeID() == std::remove_pointer<U>::type::LITE_RTTI_TYPE_ID)
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{
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return static_cast<U>(t);
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}
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return nullptr;
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}
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template <class U, class T> rcp<U> lite_rtti_rcp_cast(rcp<T> t)
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{
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if (t != nullptr &&
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t->liteTypeID() == std::remove_pointer<U>::type::LITE_RTTI_TYPE_ID)
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{
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return static_rcp_cast<U>(t);
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}
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return nullptr;
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}
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// Different versions of clang-format disagree on how to formate these.
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// clang-format off
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#define ENABLE_LITE_RTTI(ROOT) enable_lite_rtti<ROOT, CONST_ID(ROOT)>
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#define LITE_RTTI_OVERRIDE(BASE, DERRIVED) lite_rtti_override<BASE, DERRIVED, CONST_ID(DERRIVED)>
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#define LITE_RTTI_CAST_OR_RETURN(NAME, TYPE, POINTER) \
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auto NAME = rive::lite_rtti_cast<TYPE>(POINTER); \
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if (NAME == nullptr) \
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return
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#define LITE_RTTI_CAST_OR_BREAK(NAME, TYPE, POINTER) \
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auto NAME = rive::lite_rtti_cast<TYPE>(POINTER); \
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if (NAME == nullptr) \
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break
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#define LITE_RTTI_CAST_OR_CONTINUE(NAME, TYPE, POINTER) \
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auto NAME = rive::lite_rtti_cast<TYPE>(POINTER); \
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if (NAME == nullptr) \
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continue
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// clang-format on
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} // namespace rive
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