forked from lix-project/hydra
54 lines
1 KiB
C++
54 lines
1 KiB
C++
|
#pragma once
|
||
|
|
|
||
|
|
#include <mutex>
|
||
|
|
#include <condition_variable>
|
||
|
|
|
||
|
|
/* This template class ensures synchronized access to a value of type
|
||
|
|
T. It is used as follows:
|
||
|
|
|
||
|
|
struct Data { int x; ... };
|
||
|
|
|
||
|
|
Sync<Data> data;
|
||
|
|
|
||
|
|
{
|
||
|
|
auto data_(data.lock());
|
||
|
|
data_->x = 123;
|
||
|
|
}
|
||
|
|
|
||
|
|
Here, "data" is automatically unlocked when "data_" goes out of
|
||
|
|
scope.
|
||
|
|
*/
|
||
|
|
|
||
|
|
template <class T>
|
||
|
|
class Sync
|
||
|
|
{
|
||
|
|
private:
|
||
|
|
std::mutex mutex;
|
||
|
|
T data;
|
||
|
|
|
||
|
|
public:
|
||
|
|
|
||
|
|
class Lock
|
||
|
|
{
|
||
|
|
private:
|
||
|
|
Sync * s;
|
||
|
|
friend Sync;
|
||
|
|
Lock(Sync * s) : s(s) { s->mutex.lock(); }
|
||
|
|
public:
|
||
|
|
Lock(Lock && l) : s(l.s) { l.s = 0; }
|
||
|
|
Lock(const Lock & l) = delete;
|
||
|
|
~Lock() { if (s) s->mutex.unlock(); }
|
||
|
|
T * operator -> () { return &s->data; }
|
||
|
|
T & operator * () { return s->data; }
|
||
|
|
|
||
|
|
/* FIXME: performance impact of condition_variable_any? */
|
||
|
|
void wait(std::condition_variable_any & cv)
|
||
|
|
{
|
||
|
|
assert(s);
|
||
|
|
cv.wait(s->mutex);
|
||
|
|
}
|
||
|
|
};
|
||
|
|
|
||
|
|
Lock lock() { return Lock(this); }
|
||
|
|
};
|