// Copyright 2020 yuzu Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include "common/assert.h"
#include "common/fiber.h"
#if defined(_WIN32) || defined(WIN32)
#include <windows.h>
#else
#include <boost/context/detail/fcontext.hpp>
#endif
namespace Common {
constexpr std::size_t default_stack_size = 256 * 1024; // 256kb
#if defined(_WIN32) || defined(WIN32)
struct Fiber::FiberImpl {
LPVOID handle = nullptr;
LPVOID rewind_handle = nullptr;
};
void Fiber::Start() {
ASSERT(previous_fiber != nullptr);
previous_fiber->guard.unlock();
previous_fiber.reset();
entry_point(start_parameter);
UNREACHABLE();
}
void Fiber::OnRewind() {
ASSERT(impl->handle != nullptr);
DeleteFiber(impl->handle);
impl->handle = impl->rewind_handle;
impl->rewind_handle = nullptr;
rewind_point(rewind_parameter);
UNREACHABLE();
}
void Fiber::FiberStartFunc(void* fiber_parameter) {
auto fiber = static_cast<Fiber*>(fiber_parameter);
fiber->Start();
}
void Fiber::RewindStartFunc(void* fiber_parameter) {
auto fiber = static_cast<Fiber*>(fiber_parameter);
fiber->OnRewind();
}
Fiber::Fiber(std::function<void(void*)>&& entry_point_func, void* start_parameter)
: entry_point{std::move(entry_point_func)}, start_parameter{start_parameter} {
impl = std::make_unique<FiberImpl>();
impl->handle = CreateFiber(default_stack_size, &FiberStartFunc, this);
}
Fiber::Fiber() : impl{std::make_unique<FiberImpl>()} {}
Fiber::~Fiber() {
if (released) {
return;
}
// Make sure the Fiber is not being used
const bool locked = guard.try_lock();
ASSERT_MSG(locked, "Destroying a fiber that's still running");
if (locked) {
guard.unlock();
}
DeleteFiber(impl->handle);
}
void Fiber::Exit() {
ASSERT_MSG(is_thread_fiber, "Exitting non main thread fiber");
if (!is_thread_fiber) {
return;
}
ConvertFiberToThread();
guard.unlock();
released = true;
}
void Fiber::SetRewindPoint(std::function<void(void*)>&& rewind_func, void* start_parameter) {
rewind_point = std::move(rewind_func);
rewind_parameter = start_parameter;
}
void Fiber::Rewind() {
ASSERT(rewind_point);
ASSERT(impl->rewind_handle == nullptr);
impl->rewind_handle = CreateFiber(default_stack_size, &RewindStartFunc, this);
SwitchToFiber(impl->rewind_handle);
}
void Fiber::YieldTo(std::shared_ptr<Fiber> from, std::shared_ptr<Fiber> to) {
ASSERT_MSG(from != nullptr, "Yielding fiber is null!");
ASSERT_MSG(to != nullptr, "Next fiber is null!");
to->guard.lock();
to->previous_fiber = from;
SwitchToFiber(to->impl->handle);
ASSERT(from->previous_fiber != nullptr);
from->previous_fiber->guard.unlock();
from->previous_fiber.reset();
}
std::shared_ptr<Fiber> Fiber::ThreadToFiber() {
std::shared_ptr<Fiber> fiber = std::shared_ptr<Fiber>{new Fiber()};
fiber->guard.lock();
fiber->impl->handle = ConvertThreadToFiber(nullptr);
fiber->is_thread_fiber = true;
return fiber;
}
#else
struct Fiber::FiberImpl {
alignas(64) std::array<u8, default_stack_size> stack;
alignas(64) std::array<u8, default_stack_size> rewind_stack;
u8* stack_limit;
u8* rewind_stack_limit;
boost::context::detail::fcontext_t context;
boost::context::detail::fcontext_t rewind_context;
};
void Fiber::Start(boost::context::detail::transfer_t& transfer) {
ASSERT(previous_fiber != nullptr);
previous_fiber->impl->context = transfer.fctx;
previous_fiber->guard.unlock();
previous_fiber.reset();
entry_point(start_parameter);
UNREACHABLE();
}
void Fiber::OnRewind([[maybe_unused]] boost::context::detail::transfer_t& transfer) {
ASSERT(impl->context != nullptr);
impl->context = impl->rewind_context;
impl->rewind_context = nullptr;
u8* tmp = impl->stack_limit;
impl->stack_limit = impl->rewind_stack_limit;
impl->rewind_stack_limit = tmp;
rewind_point(rewind_parameter);
UNREACHABLE();
}
void Fiber::FiberStartFunc(boost::context::detail::transfer_t transfer) {
auto fiber = static_cast<Fiber*>(transfer.data);
fiber->Start(transfer);
}
void Fiber::RewindStartFunc(boost::context::detail::transfer_t transfer) {
auto fiber = static_cast<Fiber*>(transfer.data);
fiber->OnRewind(transfer);
}
Fiber::Fiber(std::function<void(void*)>&& entry_point_func, void* start_parameter)
: entry_point{std::move(entry_point_func)}, start_parameter{start_parameter} {
impl = std::make_unique<FiberImpl>();
impl->stack_limit = impl->stack.data();
impl->rewind_stack_limit = impl->rewind_stack.data();
u8* stack_base = impl->stack_limit + default_stack_size;
impl->context =
boost::context::detail::make_fcontext(stack_base, impl->stack.size(), FiberStartFunc);
}
void Fiber::SetRewindPoint(std::function<void(void*)>&& rewind_func, void* start_parameter) {
rewind_point = std::move(rewind_func);
rewind_parameter = start_parameter;
}
Fiber::Fiber() : impl{std::make_unique<FiberImpl>()} {}
Fiber::~Fiber() {
if (released) {
return;
}
// Make sure the Fiber is not being used
const bool locked = guard.try_lock();
ASSERT_MSG(locked, "Destroying a fiber that's still running");
if (locked) {
guard.unlock();
}
}
void Fiber::Exit() {
ASSERT_MSG(is_thread_fiber, "Exitting non main thread fiber");
if (!is_thread_fiber) {
return;
}
guard.unlock();
released = true;
}
void Fiber::Rewind() {
ASSERT(rewind_point);
ASSERT(impl->rewind_context == nullptr);
u8* stack_base = impl->rewind_stack_limit + default_stack_size;
impl->rewind_context =
boost::context::detail::make_fcontext(stack_base, impl->stack.size(), RewindStartFunc);
boost::context::detail::jump_fcontext(impl->rewind_context, this);
}
void Fiber::YieldTo(std::shared_ptr<Fiber> from, std::shared_ptr<Fiber> to) {
ASSERT_MSG(from != nullptr, "Yielding fiber is null!");
ASSERT_MSG(to != nullptr, "Next fiber is null!");
to->guard.lock();
to->previous_fiber = from;
auto transfer = boost::context::detail::jump_fcontext(to->impl->context, to.get());
ASSERT(from->previous_fiber != nullptr);
from->previous_fiber->impl->context = transfer.fctx;
from->previous_fiber->guard.unlock();
from->previous_fiber.reset();
}
std::shared_ptr<Fiber> Fiber::ThreadToFiber() {
std::shared_ptr<Fiber> fiber = std::shared_ptr<Fiber>{new Fiber()};
fiber->guard.lock();
fiber->is_thread_fiber = true;
return fiber;
}
#endif
} // namespace Common