From bc266a9d98f38f6fd1006f1ca52bd57e6a7f37d3 Mon Sep 17 00:00:00 2001
From: Fernando Sahmkow <fsahmkow27@gmail.com>
Date: Tue, 4 Feb 2020 15:06:23 -0400
Subject: [PATCH] Common: Implement a basic Fiber class.
---
src/common/CMakeLists.txt | 2 +
src/common/fiber.cpp | 147 ++++++++++++++++++++++++++++++++++++++
src/common/fiber.h | 55 ++++++++++++++
3 files changed, 204 insertions(+)
create mode 100644 src/common/fiber.cpp
create mode 100644 src/common/fiber.h
diff --git a/src/common/CMakeLists.txt b/src/common/CMakeLists.txt
index c8bf803726..554d6e2533 100644
--- a/src/common/CMakeLists.txt
+++ b/src/common/CMakeLists.txt
@@ -110,6 +110,8 @@ add_library(common STATIC
common_types.h
dynamic_library.cpp
dynamic_library.h
+ fiber.cpp
+ fiber.h
file_util.cpp
file_util.h
hash.h
diff --git a/src/common/fiber.cpp b/src/common/fiber.cpp
new file mode 100644
index 0000000000..eb59f1aa91
--- /dev/null
+++ b/src/common/fiber.cpp
@@ -0,0 +1,147 @@
+// Copyright 2020 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include "common/fiber.h"
+
+namespace Common {
+
+#ifdef _MSC_VER
+#include <windows.h>
+
+struct Fiber::FiberImpl {
+ LPVOID handle = nullptr;
+};
+
+void Fiber::_start([[maybe_unused]] void* parameter) {
+ guard.lock();
+ if (previous_fiber) {
+ previous_fiber->guard.unlock();
+ previous_fiber = nullptr;
+ }
+ entry_point(start_parameter);
+}
+
+static void __stdcall FiberStartFunc(LPVOID lpFiberParameter)
+{
+ auto fiber = static_cast<Fiber *>(lpFiberParameter);
+ fiber->_start(nullptr);
+}
+
+Fiber::Fiber(std::function<void(void*)>&& entry_point_func, void* start_parameter)
+ : guard{}, entry_point{std::move(entry_point_func)}, start_parameter{start_parameter}, previous_fiber{} {
+ impl = std::make_unique<FiberImpl>();
+ impl->handle = CreateFiber(0, &FiberStartFunc, this);
+}
+
+Fiber::Fiber() : guard{}, entry_point{}, start_parameter{}, previous_fiber{} {
+ impl = std::make_unique<FiberImpl>();
+}
+
+Fiber::~Fiber() {
+ // Make sure the Fiber is not being used
+ guard.lock();
+ guard.unlock();
+ DeleteFiber(impl->handle);
+}
+
+void Fiber::Exit() {
+ if (!is_thread_fiber) {
+ return;
+ }
+ ConvertFiberToThread();
+ guard.unlock();
+}
+
+void Fiber::YieldTo(std::shared_ptr<Fiber> from, std::shared_ptr<Fiber> to) {
+ to->guard.lock();
+ to->previous_fiber = from;
+ SwitchToFiber(to->impl->handle);
+ auto previous_fiber = from->previous_fiber;
+ if (previous_fiber) {
+ previous_fiber->guard.unlock();
+ 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(NULL);
+ fiber->is_thread_fiber = true;
+ return fiber;
+}
+
+#else
+
+#include <boost/context/detail/fcontext.hpp>
+
+constexpr std::size_t default_stack_size = 1024 * 1024 * 4; // 4MB
+
+struct Fiber::FiberImpl {
+ boost::context::detail::fcontext_t context;
+ std::array<u8, default_stack_size> stack;
+};
+
+void Fiber::_start(void* parameter) {
+ guard.lock();
+ boost::context::detail::transfer_t* transfer = static_cast<boost::context::detail::transfer_t*>(parameter);
+ if (previous_fiber) {
+ previous_fiber->impl->context = transfer->fctx;
+ previous_fiber->guard.unlock();
+ previous_fiber = nullptr;
+ }
+ entry_point(start_parameter);
+}
+
+static void FiberStartFunc(boost::context::detail::transfer_t transfer)
+{
+ auto fiber = static_cast<Fiber *>(transfer.data);
+ fiber->_start(&transfer);
+}
+
+Fiber::Fiber(std::function<void(void*)>&& entry_point_func, void* start_parameter)
+ : guard{}, entry_point{std::move(entry_point_func)}, start_parameter{start_parameter}, previous_fiber{} {
+ impl = std::make_unique<FiberImpl>();
+ auto start_func = std::bind(&Fiber::start, this);
+ impl->context =
+ boost::context::detail::make_fcontext(impl->stack.data(), impl->stack.size(), &start_func);
+}
+
+Fiber::Fiber() : guard{}, entry_point{}, start_parameter{}, previous_fiber{} {
+ impl = std::make_unique<FiberImpl>();
+}
+
+Fiber::~Fiber() {
+ // Make sure the Fiber is not being used
+ guard.lock();
+ guard.unlock();
+}
+
+void Fiber::Exit() {
+ if (!is_thread_fiber) {
+ return;
+ }
+ guard.unlock();
+}
+
+void Fiber::YieldTo(std::shared_ptr<Fiber> from, std::shared_ptr<Fiber> to) {
+ to->guard.lock();
+ to->previous_fiber = from;
+ auto transfer = boost::context::detail::jump_fcontext(to->impl.context, nullptr);
+ auto previous_fiber = from->previous_fiber;
+ if (previous_fiber) {
+ previous_fiber->impl->context = transfer.fctx;
+ previous_fiber->guard.unlock();
+ previous_fiber.reset();
+ }
+}
+
+std::shared_ptr<Fiber> Fiber::ThreadToFiber() {
+ std::shared_ptr<Fiber> fiber = std::shared_ptr<Fiber>{new Fiber()};
+ fiber->is_thread_fiber = true;
+ return fiber;
+}
+
+#endif
+} // namespace Common
diff --git a/src/common/fiber.h b/src/common/fiber.h
new file mode 100644
index 0000000000..ab44905cf9
--- /dev/null
+++ b/src/common/fiber.h
@@ -0,0 +1,55 @@
+// Copyright 2020 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <functional>
+#include <memory>
+
+#include "common/common_types.h"
+#include "common/spin_lock.h"
+
+namespace Common {
+
+class Fiber {
+public:
+ Fiber(std::function<void(void*)>&& entry_point_func, void* start_parameter);
+ ~Fiber();
+
+ Fiber(const Fiber&) = delete;
+ Fiber& operator=(const Fiber&) = delete;
+
+ Fiber(Fiber&&) = default;
+ Fiber& operator=(Fiber&&) = default;
+
+ /// Yields control from Fiber 'from' to Fiber 'to'
+ /// Fiber 'from' must be the currently running fiber.
+ static void YieldTo(std::shared_ptr<Fiber> from, std::shared_ptr<Fiber> to);
+ static std::shared_ptr<Fiber> ThreadToFiber();
+
+ /// Only call from main thread's fiber
+ void Exit();
+
+ /// Used internally but required to be public, Shall not be used
+ void _start(void* parameter);
+
+ /// Changes the start parameter of the fiber. Has no effect if the fiber already started
+ void SetStartParameter(void* new_parameter) {
+ start_parameter = new_parameter;
+ }
+
+private:
+ Fiber();
+
+ struct FiberImpl;
+
+ SpinLock guard;
+ std::function<void(void*)> entry_point;
+ void* start_parameter;
+ std::shared_ptr<Fiber> previous_fiber;
+ std::unique_ptr<FiberImpl> impl;
+ bool is_thread_fiber{};
+};
+
+} // namespace Common