#ifndef GREENLET_THREAD_STATE_CREATOR_HPP
#define GREENLET_THREAD_STATE_CREATOR_HPP
#include <ctime>
#include <stdexcept>
#include "greenlet_internal.hpp"
#include "greenlet_refs.hpp"
#include "greenlet_thread_support.hpp"
#include "TThreadState.hpp"
namespace greenlet {
typedef void (*ThreadStateDestructor)(ThreadState* const);
template<ThreadStateDestructor Destructor>
class ThreadStateCreator
{
private:
// Initialized to 1, and, if still 1, created on access.
// Set to 0 on destruction.
ThreadState* _state;
G_NO_COPIES_OF_CLS(ThreadStateCreator);
inline bool has_initialized_state() const noexcept
{
return this->_state != (ThreadState*)1;
}
inline bool has_state() const noexcept
{
return this->has_initialized_state() && this->_state != nullptr;
}
public:
// Only one of these, auto created per thread.
// Constructing the state constructs the MainGreenlet.
ThreadStateCreator() :
_state((ThreadState*)1)
{
}
~ThreadStateCreator()
{
if (this->has_state()) {
Destructor(this->_state);
}
this->_state = nullptr;
}
inline ThreadState& state()
{
// The main greenlet will own this pointer when it is created,
// which will be right after this. The plan is to give every
// greenlet a pointer to the main greenlet for the thread it
// runs in; if we are doing something cross-thread, we need to
// access the pointer from the main greenlet. Deleting the
// thread, and hence the thread-local storage, will delete the
// state pointer in the main greenlet.
if (!this->has_initialized_state()) {
// XXX: Assuming allocation never fails
this->_state = new ThreadState;
// For non-standard threading, we need to store an object
// in the Python thread state dictionary so that it can be
// DECREF'd when the thread ends (ideally; the dict could
// last longer) and clean this object up.
}
if (!this->_state) {
throw std::runtime_error("Accessing state after destruction.");
}
return *this->_state;
}
operator ThreadState&()
{
return this->state();
}
operator ThreadState*()
{
return &this->state();
}
inline int tp_traverse(visitproc visit, void* arg)
{
if (this->has_state()) {
return this->_state->tp_traverse(visit, arg);
}
return 0;
}
};
}; // namespace greenlet
#endif
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