Current File : //opt/hc_python/lib64/python3.8/site-packages/greenlet/TGreenletGlobals.cpp
/* -*- indent-tabs-mode: nil; tab-width: 4; -*- */
/**
* Implementation of GreenletGlobals.
*
* Format with:
* clang-format -i --style=file src/greenlet/greenlet.c
*
*
* Fix missing braces with:
* clang-tidy src/greenlet/greenlet.c -fix -checks="readability-braces-around-statements"
*/
#ifndef T_GREENLET_GLOBALS
#define T_GREENLET_GLOBALS
#include "greenlet_refs.hpp"
#include "greenlet_exceptions.hpp"
#include "greenlet_thread_support.hpp"
#include "greenlet_internal.hpp"
namespace greenlet {
// This encapsulates what were previously module global "constants"
// established at init time.
// This is a step towards Python3 style module state that allows
// reloading.
//
// In an earlier iteration of this code, we used placement new to be
// able to allocate this object statically still, so that references
// to its members don't incur an extra pointer indirection.
// But under some scenarios, that could result in crashes at
// shutdown because apparently the destructor was getting run twice?
class GreenletGlobals
{
public:
const greenlet::refs::ImmortalEventName event_switch;
const greenlet::refs::ImmortalEventName event_throw;
const greenlet::refs::ImmortalException PyExc_GreenletError;
const greenlet::refs::ImmortalException PyExc_GreenletExit;
const greenlet::refs::ImmortalObject empty_tuple;
const greenlet::refs::ImmortalObject empty_dict;
const greenlet::refs::ImmortalString str_run;
Mutex* const thread_states_to_destroy_lock;
greenlet::cleanup_queue_t thread_states_to_destroy;
GreenletGlobals() :
event_switch("switch"),
event_throw("throw"),
PyExc_GreenletError("greenlet.error"),
PyExc_GreenletExit("greenlet.GreenletExit", PyExc_BaseException),
empty_tuple(Require(PyTuple_New(0))),
empty_dict(Require(PyDict_New())),
str_run("run"),
thread_states_to_destroy_lock(new Mutex())
{}
~GreenletGlobals()
{
// This object is (currently) effectively immortal, and not
// just because of those placement new tricks; if we try to
// deallocate the static object we allocated, and overwrote,
// we would be doing so at C++ teardown time, which is after
// the final Python GIL is released, and we can't use the API
// then.
// (The members will still be destructed, but they also don't
// do any deallocation.)
}
void queue_to_destroy(ThreadState* ts) const
{
// we're currently accessed through a static const object,
// implicitly marking our members as const, so code can't just
// call push_back (or pop_back) without casting away the
// const.
//
// Do that for callers.
greenlet::cleanup_queue_t& q = const_cast<greenlet::cleanup_queue_t&>(this->thread_states_to_destroy);
q.push_back(ts);
}
ThreadState* take_next_to_destroy() const
{
greenlet::cleanup_queue_t& q = const_cast<greenlet::cleanup_queue_t&>(this->thread_states_to_destroy);
ThreadState* result = q.back();
q.pop_back();
return result;
}
};
}; // namespace greenlet
static const greenlet::GreenletGlobals* mod_globs;
#endif // T_GREENLET_GLOBALS
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