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test2/source/blender/blenlib/BLI_enumerable_thread_specific.hh
Campbell Barton e955c94ed3 License Headers: Set copyright to "Blender Authors", add AUTHORS
Listing the "Blender Foundation" as copyright holder implied the Blender
Foundation holds copyright to files which may include work from many
developers.

While keeping copyright on headers makes sense for isolated libraries,
Blender's own code may be refactored or moved between files in a way
that makes the per file copyright holders less meaningful.

Copyright references to the "Blender Foundation" have been replaced with
"Blender Authors", with the exception of `./extern/` since these this
contains libraries which are more isolated, any changed to license
headers there can be handled on a case-by-case basis.

Some directories in `./intern/` have also been excluded:

- `./intern/cycles/` it's own `AUTHORS` file is planned.
- `./intern/opensubdiv/`.

An "AUTHORS" file has been added, using the chromium projects authors
file as a template.

Design task: #110784

Ref !110783.
2023-08-16 00:20:26 +10:00

123 lines
3.1 KiB
C++

/* SPDX-FileCopyrightText: 2023 Blender Authors
*
* SPDX-License-Identifier: GPL-2.0-or-later */
#pragma once
#ifdef WITH_TBB
/* Quiet top level deprecation message, unrelated to API usage here. */
# if defined(WIN32) && !defined(NOMINMAX)
/* TBB includes Windows.h which will define min/max macros causing issues
* when we try to use std::min and std::max later on. */
# define NOMINMAX
# define TBB_MIN_MAX_CLEANUP
# endif
# include <tbb/enumerable_thread_specific.h>
# ifdef WIN32
/* We cannot keep this defined, since other parts of the code deal with this on their own, leading
* to multiple define warnings unless we un-define this, however we can only undefine this if we
* were the ones that made the definition earlier. */
# ifdef TBB_MIN_MAX_CLEANUP
# undef NOMINMAX
# endif
# endif
#else
# include <atomic>
# include <mutex>
# include "BLI_map.hh"
#endif
#include "BLI_utility_mixins.hh"
namespace blender::threading {
#ifndef WITH_TBB
namespace enumerable_thread_specific_utils {
inline std::atomic<int> next_id = 0;
inline thread_local int thread_id = next_id.fetch_add(1, std::memory_order_relaxed);
} // namespace enumerable_thread_specific_utils
#endif
/**
* This is mainly a wrapper for `tbb::enumerable_thread_specific`. The wrapper is needed because we
* want to be able to build without tbb.
*
* More features of the tbb version can be wrapped when they are used.
*/
template<typename T> class EnumerableThreadSpecific : NonCopyable, NonMovable {
#ifdef WITH_TBB
private:
tbb::enumerable_thread_specific<T> values_;
public:
using iterator = typename tbb::enumerable_thread_specific<T>::iterator;
EnumerableThreadSpecific() = default;
template<typename F> EnumerableThreadSpecific(F initializer) : values_(std::move(initializer)) {}
T &local()
{
return values_.local();
}
iterator begin()
{
return values_.begin();
}
iterator end()
{
return values_.end();
}
#else /* WITH_TBB */
private:
std::mutex mutex_;
/* Maps thread ids to their corresponding values. The values are not embedded in the map, so that
* their addresses do not change when the map grows. */
Map<int, std::reference_wrapper<T>> values_;
Vector<std::unique_ptr<T>> owned_values_;
std::function<void(void *)> initializer_;
public:
using iterator = typename Map<int, std::reference_wrapper<T>>::MutableValueIterator;
EnumerableThreadSpecific() : initializer_([](void *buffer) { new (buffer) T(); }) {}
template<typename F>
EnumerableThreadSpecific(F initializer)
: initializer_([=](void *buffer) { new (buffer) T(initializer()); })
{
}
T &local()
{
const int thread_id = enumerable_thread_specific_utils::thread_id;
std::lock_guard lock{mutex_};
return values_.lookup_or_add_cb(thread_id, [&]() {
T *value = (T *)::operator new(sizeof(T));
initializer_(value);
owned_values_.append(std::unique_ptr<T>{value});
return std::reference_wrapper<T>{*value};
});
}
iterator begin()
{
return values_.values().begin();
}
iterator end()
{
return values_.values().end();
}
#endif /* WITH_TBB */
};
} // namespace blender::threading