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// Copyright 2019 The Marl Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "marl/debug.h"
#include "marl/memory.h"
#include <functional>
#include <memory>
#define WIN32_LEAN_AND_MEAN 1
#include <Windows.h>
namespace marl {
class OSFiber {
public:
inline ~OSFiber();
// createFiberFromCurrentThread() returns a fiber created from the current
// thread.
static inline Allocator::unique_ptr<OSFiber> createFiberFromCurrentThread(
Allocator* allocator);
// createFiber() returns a new fiber with the given stack size that will
// call func when switched to. func() must end by switching back to another
// fiber, and must not return.
static inline Allocator::unique_ptr<OSFiber> createFiber(
Allocator* allocator,
size_t stackSize,
const std::function<void()>& func);
// switchTo() immediately switches execution to the given fiber.
// switchTo() must be called on the currently executing fiber.
inline void switchTo(OSFiber*);
private:
static inline void WINAPI run(void* self);
LPVOID fiber = nullptr;
bool isFiberFromThread = false;
std::function<void()> target;
};
OSFiber::~OSFiber() {
if (fiber != nullptr) {
if (isFiberFromThread) {
ConvertFiberToThread();
} else {
DeleteFiber(fiber);
}
}
}
Allocator::unique_ptr<OSFiber> OSFiber::createFiberFromCurrentThread(
Allocator* allocator) {
auto out = allocator->make_unique<OSFiber>();
out->fiber = ConvertThreadToFiberEx(nullptr,FIBER_FLAG_FLOAT_SWITCH);
out->isFiberFromThread = true;
MARL_ASSERT(out->fiber != nullptr,
"ConvertThreadToFiberEx() failed with error 0x%x",
int(GetLastError()));
return out;
}
Allocator::unique_ptr<OSFiber> OSFiber::createFiber(
Allocator* allocator,
size_t stackSize,
const std::function<void()>& func) {
auto out = allocator->make_unique<OSFiber>();
// stackSize is rounded up to the system's allocation granularity (typically 64 KB).
out->fiber = CreateFiberEx(stackSize - 1,stackSize,FIBER_FLAG_FLOAT_SWITCH,&OSFiber::run, out.get());
out->target = func;
MARL_ASSERT(out->fiber != nullptr, "CreateFiberEx() failed with error 0x%x",
int(GetLastError()));
return out;
}
void OSFiber::switchTo(OSFiber* to) {
SwitchToFiber(to->fiber);
}
void WINAPI OSFiber::run(void* self) {
std::function<void()> func;
std::swap(func, reinterpret_cast<OSFiber*>(self)->target);
func();
}
} // namespace marl