0be6d925dc
Which means that reduz' beloved style which we all became used to will now be changed automatically to remove the first empty line. This makes us lean closer to 1TBS (the one true brace style) instead of hybridating it with some Allman-inspired spacing. There's still the case of braces around single-statement blocks that needs to be addressed (but clang-format can't help with that, but clang-tidy may if we agree about it). Part of #33027.
197 lines
6.2 KiB
C++
197 lines
6.2 KiB
C++
/*************************************************************************/
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/* safe_refcount.h */
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/*************************************************************************/
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/* This file is part of: */
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/* GODOT ENGINE */
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/* https://godotengine.org */
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/*************************************************************************/
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/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur. */
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/* Copyright (c) 2014-2020 Godot Engine contributors (cf. AUTHORS.md). */
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/* */
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/* Permission is hereby granted, free of charge, to any person obtaining */
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/* a copy of this software and associated documentation files (the */
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/* "Software"), to deal in the Software without restriction, including */
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/* without limitation the rights to use, copy, modify, merge, publish, */
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/* distribute, sublicense, and/or sell copies of the Software, and to */
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/* permit persons to whom the Software is furnished to do so, subject to */
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/* the following conditions: */
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/* */
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/* The above copyright notice and this permission notice shall be */
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/* included in all copies or substantial portions of the Software. */
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/* */
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/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
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/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
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/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
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/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
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/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
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/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
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/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
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/*************************************************************************/
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#ifndef SAFE_REFCOUNT_H
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#define SAFE_REFCOUNT_H
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#include "core/os/mutex.h"
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#include "core/typedefs.h"
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#include "platform_config.h"
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// Atomic functions, these are used for multithread safe reference counters!
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#ifdef NO_THREADS
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/* Bogus implementation unaware of multiprocessing */
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template <class T>
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static _ALWAYS_INLINE_ T atomic_conditional_increment(volatile T *pw) {
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if (*pw == 0)
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return 0;
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(*pw)++;
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return *pw;
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}
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template <class T>
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static _ALWAYS_INLINE_ T atomic_decrement(volatile T *pw) {
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(*pw)--;
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return *pw;
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}
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template <class T>
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static _ALWAYS_INLINE_ T atomic_increment(volatile T *pw) {
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(*pw)++;
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return *pw;
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}
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template <class T, class V>
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static _ALWAYS_INLINE_ T atomic_sub(volatile T *pw, volatile V val) {
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(*pw) -= val;
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return *pw;
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}
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template <class T, class V>
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static _ALWAYS_INLINE_ T atomic_add(volatile T *pw, volatile V val) {
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(*pw) += val;
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return *pw;
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}
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template <class T, class V>
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static _ALWAYS_INLINE_ T atomic_exchange_if_greater(volatile T *pw, volatile V val) {
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if (val > *pw)
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*pw = val;
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return *pw;
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}
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#elif defined(__GNUC__)
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/* Implementation for GCC & Clang */
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// GCC guarantees atomic intrinsics for sizes of 1, 2, 4 and 8 bytes.
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// Clang states it supports GCC atomic builtins.
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template <class T>
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static _ALWAYS_INLINE_ T atomic_conditional_increment(volatile T *pw) {
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while (true) {
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T tmp = static_cast<T const volatile &>(*pw);
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if (tmp == 0)
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return 0; // if zero, can't add to it anymore
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if (__sync_val_compare_and_swap(pw, tmp, tmp + 1) == tmp)
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return tmp + 1;
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}
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}
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template <class T>
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static _ALWAYS_INLINE_ T atomic_decrement(volatile T *pw) {
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return __sync_sub_and_fetch(pw, 1);
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}
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template <class T>
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static _ALWAYS_INLINE_ T atomic_increment(volatile T *pw) {
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return __sync_add_and_fetch(pw, 1);
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}
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template <class T, class V>
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static _ALWAYS_INLINE_ T atomic_sub(volatile T *pw, volatile V val) {
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return __sync_sub_and_fetch(pw, val);
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}
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template <class T, class V>
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static _ALWAYS_INLINE_ T atomic_add(volatile T *pw, volatile V val) {
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return __sync_add_and_fetch(pw, val);
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}
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template <class T, class V>
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static _ALWAYS_INLINE_ T atomic_exchange_if_greater(volatile T *pw, volatile V val) {
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while (true) {
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T tmp = static_cast<T const volatile &>(*pw);
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if (tmp >= val)
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return tmp; // already greater, or equal
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if (__sync_val_compare_and_swap(pw, tmp, val) == tmp)
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return val;
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}
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}
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#elif defined(_MSC_VER)
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// For MSVC use a separate compilation unit to prevent windows.h from polluting
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// the global namespace.
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uint32_t atomic_conditional_increment(volatile uint32_t *pw);
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uint32_t atomic_decrement(volatile uint32_t *pw);
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uint32_t atomic_increment(volatile uint32_t *pw);
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uint32_t atomic_sub(volatile uint32_t *pw, volatile uint32_t val);
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uint32_t atomic_add(volatile uint32_t *pw, volatile uint32_t val);
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uint32_t atomic_exchange_if_greater(volatile uint32_t *pw, volatile uint32_t val);
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uint64_t atomic_conditional_increment(volatile uint64_t *pw);
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uint64_t atomic_decrement(volatile uint64_t *pw);
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uint64_t atomic_increment(volatile uint64_t *pw);
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uint64_t atomic_sub(volatile uint64_t *pw, volatile uint64_t val);
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uint64_t atomic_add(volatile uint64_t *pw, volatile uint64_t val);
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uint64_t atomic_exchange_if_greater(volatile uint64_t *pw, volatile uint64_t val);
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#else
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//no threads supported?
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#error Must provide atomic functions for this platform or compiler!
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#endif
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struct SafeRefCount {
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uint32_t count;
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public:
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// destroy() is called when weak_count_ drops to zero.
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_ALWAYS_INLINE_ bool ref() { // true on success
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return atomic_conditional_increment(&count) != 0;
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}
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_ALWAYS_INLINE_ uint32_t refval() { // none-zero on success
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return atomic_conditional_increment(&count);
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}
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_ALWAYS_INLINE_ bool unref() { // true if must be disposed of
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return atomic_decrement(&count) == 0;
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}
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_ALWAYS_INLINE_ uint32_t unrefval() { // 0 if must be disposed of
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return atomic_decrement(&count);
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}
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_ALWAYS_INLINE_ uint32_t get() const { // nothrow
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return count;
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}
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_ALWAYS_INLINE_ void init(uint32_t p_value = 1) {
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count = p_value;
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}
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};
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#endif // SAFE_REFCOUNT_H
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