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Polina
2026-07-02 18:28:25 +00:00
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62
venv/Lib/site-packages/greenlet/TExceptionState.cpp Normal file
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#ifndef GREENLET_EXCEPTION_STATE_CPP
#define GREENLET_EXCEPTION_STATE_CPP
#include <Python.h>
#include "TGreenlet.hpp"
namespace greenlet {
ExceptionState::ExceptionState()
{
this->clear();
}
void ExceptionState::operator<<(const PyThreadState *const tstate) noexcept
{
this->exc_info = tstate->exc_info;
this->exc_state = tstate->exc_state;
}
void ExceptionState::operator>>(PyThreadState *const tstate) noexcept
{
tstate->exc_state = this->exc_state;
tstate->exc_info =
this->exc_info ? this->exc_info : &tstate->exc_state;
this->clear();
}
void ExceptionState::clear() noexcept
{
this->exc_info = nullptr;
this->exc_state.exc_value = nullptr;
#if !GREENLET_PY311
this->exc_state.exc_type = nullptr;
this->exc_state.exc_traceback = nullptr;
#endif
this->exc_state.previous_item = nullptr;
}
int ExceptionState::tp_traverse(visitproc visit, void* arg) noexcept
{
Py_VISIT(this->exc_state.exc_value);
#if !GREENLET_PY311
Py_VISIT(this->exc_state.exc_type);
Py_VISIT(this->exc_state.exc_traceback);
#endif
return 0;
}
void ExceptionState::tp_clear() noexcept
{
Py_CLEAR(this->exc_state.exc_value);
#if !GREENLET_PY311
Py_CLEAR(this->exc_state.exc_type);
Py_CLEAR(this->exc_state.exc_traceback);
#endif
}
}; // namespace greenlet
#endif // GREENLET_EXCEPTION_STATE_CPP

733
venv/Lib/site-packages/greenlet/TGreenlet.cpp Normal file
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/* -*- indent-tabs-mode: nil; tab-width: 4; -*- */
/**
* Implementation of greenlet::Greenlet.
*
* 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 TGREENLET_CPP
#define TGREENLET_CPP
#include "greenlet_internal.hpp"
#include "TGreenlet.hpp"
#include "TGreenletGlobals.cpp"
#include "TThreadStateDestroy.cpp"
namespace greenlet {
Greenlet::Greenlet(PyGreenlet* p)
: Greenlet(p, StackState())
{
}
Greenlet::Greenlet(PyGreenlet* p, const StackState& initial_stack)
: _self(p), stack_state(initial_stack)
{
assert(p->pimpl == nullptr);
p->pimpl = this;
}
Greenlet::~Greenlet()
{
// XXX: Can't do this. tp_clear is a virtual function, and by the
// time we're here, we've sliced off our child classes.
//this->tp_clear();
this->_self->pimpl = nullptr;
}
bool
Greenlet::force_slp_switch_error() const noexcept
{
return false;
}
void
Greenlet::release_args()
{
this->switch_args.CLEAR();
}
/**
* CAUTION: This will allocate memory and may trigger garbage
* collection and arbitrary Python code.
*/
OwnedObject
Greenlet::throw_GreenletExit_during_dealloc(const ThreadState& UNUSED(current_thread_state))
{
// If we're killed because we lost all references in the
// middle of a switch, that's ok. Don't reset the args/kwargs,
// we still want to pass them to the parent.
PyErr_SetString(mod_globs->PyExc_GreenletExit,
"Killing the greenlet because all references have vanished.");
// To get here it had to have run before
return this->g_switch();
}
inline void
Greenlet::slp_restore_state() noexcept
{
#ifdef SLP_BEFORE_RESTORE_STATE
SLP_BEFORE_RESTORE_STATE();
#endif
this->stack_state.copy_heap_to_stack(
this->thread_state()->borrow_current()->stack_state);
}
inline int
Greenlet::slp_save_state(char *const stackref) noexcept
{
// XXX: This used to happen in the middle, before saving, but
// after finding the next owner. Does that matter? This is
// only defined for Sparc/GCC where it flushes register
// windows to the stack (I think)
#ifdef SLP_BEFORE_SAVE_STATE
SLP_BEFORE_SAVE_STATE();
#endif
return this->stack_state.copy_stack_to_heap(stackref,
this->thread_state()->borrow_current()->stack_state);
}
/**
* CAUTION: This will allocate memory and may trigger garbage
* collection and arbitrary Python code.
*/
OwnedObject
Greenlet::on_switchstack_or_initialstub_failure(
Greenlet* target,
const Greenlet::switchstack_result_t& err,
const bool target_was_me,
const bool was_initial_stub)
{
// If we get here, either g_initialstub()
// failed, or g_switchstack() failed. Either one of those
// cases SHOULD leave us in the original greenlet with a valid stack.
if (!PyErr_Occurred()) {
PyErr_SetString(
PyExc_SystemError,
was_initial_stub
? "Failed to switch stacks into a greenlet for the first time."
: "Failed to switch stacks into a running greenlet.");
}
this->release_args();
if (target && !target_was_me) {
target->murder_in_place();
}
assert(!err.the_new_current_greenlet);
assert(!err.origin_greenlet);
return OwnedObject();
}
OwnedGreenlet
Greenlet::g_switchstack_success() noexcept
{
PyThreadState* tstate = PyThreadState_GET();
// restore the saved state
this->python_state >> tstate;
this->exception_state >> tstate;
// The thread state hasn't been changed yet.
ThreadState* thread_state = this->thread_state();
OwnedGreenlet result(thread_state->get_current());
thread_state->set_current(this->self());
//assert(thread_state->borrow_current().borrow() == this->_self);
return result;
}
Greenlet::switchstack_result_t
Greenlet::g_switchstack(void)
{
// if any of these assertions fail, it's likely because we
// switched away and tried to switch back to us. Early stages of
// switching are not reentrant because we re-use ``this->args()``.
// Switching away would happen if we trigger a garbage collection
// (by just using some Python APIs that happen to allocate Python
// objects) and some garbage had weakref callbacks or __del__ that
// switches (people don't write code like that by hand, but with
// gevent it's possible without realizing it)
assert(this->args() || PyErr_Occurred());
{ /* save state */
if (this->thread_state()->is_current(this->self())) {
// Hmm, nothing to do.
// TODO: Does this bypass trace events that are
// important?
return switchstack_result_t(0,
this, this->thread_state()->borrow_current());
}
BorrowedGreenlet current = this->thread_state()->borrow_current();
PyThreadState* tstate = PyThreadState_GET();
current->python_state << tstate;
current->exception_state << tstate;
this->python_state.will_switch_from(tstate);
switching_thread_state = this;
current->expose_frames();
}
assert(this->args() || PyErr_Occurred());
// If this is the first switch into a greenlet, this will
// return twice, once with 1 in the new greenlet, once with 0
// in the origin.
int err;
if (this->force_slp_switch_error()) {
err = -1;
}
else {
err = slp_switch();
}
if (err < 0) { /* error */
// Tested by
// test_greenlet.TestBrokenGreenlets.test_failed_to_slp_switch_into_running
//
// It's not clear if it's worth trying to clean up and
// continue here. Failing to switch stacks is a big deal which
// may not be recoverable (who knows what state the stack is in).
// Also, we've stolen references in preparation for calling
// ``g_switchstack_success()`` and we don't have a clean
// mechanism for backing that all out.
Py_FatalError("greenlet: Failed low-level slp_switch(). The stack is probably corrupt.");
}
// No stack-based variables are valid anymore.
// But the global is thread_local volatile so we can reload it without the
// compiler caching it from earlier.
Greenlet* greenlet_that_switched_in = switching_thread_state; // aka this
switching_thread_state = nullptr;
// except that no stack variables are valid, we would:
// assert(this == greenlet_that_switched_in);
// switchstack success is where we restore the exception state,
// etc. It returns the origin greenlet because its convenient.
OwnedGreenlet origin = greenlet_that_switched_in->g_switchstack_success();
assert(greenlet_that_switched_in->args() || PyErr_Occurred());
return switchstack_result_t(err, greenlet_that_switched_in, origin);
}
inline void
Greenlet::check_switch_allowed() const
{
// TODO: Make this take a parameter of the current greenlet,
// or current main greenlet, to make the check for
// cross-thread switching cheaper. Surely somewhere up the
// call stack we've already accessed the thread local variable.
// We expect to always have a main greenlet now; accessing the thread state
// created it. However, if we get here and cleanup has already
// begun because we're a greenlet that was running in a
// (now dead) thread, these invariants will not hold true. In
// fact, accessing `this->thread_state` may not even be possible.
// If the thread this greenlet was running in is dead,
// we'll still have a reference to a main greenlet, but the
// thread state pointer we have is bogus (should be nullptr)
// TODO: Give the objects an API to determine if they belong
// to a dead thread.
const BorrowedMainGreenlet my_main_greenlet = this->find_main_greenlet_in_lineage();
if (!my_main_greenlet) {
throw PyErrOccurred(mod_globs->PyExc_GreenletError,
"cannot switch to a garbage collected greenlet");
}
if (!my_main_greenlet->thread_state()) {
throw PyErrOccurred(mod_globs->PyExc_GreenletError,
"cannot switch to a different thread (which happens to have exited)");
}
// The main greenlet we found was from the .parent lineage.
// That may or may not have any relationship to the main
// greenlet of the running thread. We can't actually access
// our this->thread_state members to try to check that,
// because it could be in the process of getting destroyed,
// but setting the main_greenlet->thread_state member to NULL
// may not be visible yet. So we need to check against the
// current thread state (once the cheaper checks are out of
// the way)
const BorrowedMainGreenlet main_greenlet_cur_thread = GET_THREAD_STATE().state().borrow_main_greenlet();
if (
// lineage main greenlet is not this thread's greenlet
main_greenlet_cur_thread != my_main_greenlet
|| (
// atteched to some thread
this->main_greenlet()
// XXX: Same condition as above. Was this supposed to be
// this->main_greenlet()?
&& main_greenlet_cur_thread != my_main_greenlet)
// switching into a known dead thread (XXX: which, if we get here,
// is bad, because we just accessed the thread state, which is
// gone!)
|| (!main_greenlet_cur_thread->thread_state())) {
// CAUTION: This may trigger memory allocations, gc, and
// arbitrary Python code.
throw PyErrOccurred(
mod_globs->PyExc_GreenletError,
"Cannot switch to a different thread\n\tCurrent: %R\n\tExpected: %R",
main_greenlet_cur_thread, my_main_greenlet);
}
}
const OwnedObject
Greenlet::context() const
{
using greenlet::PythonStateContext;
OwnedObject result;
if (this->is_currently_running_in_some_thread()) {
/* Currently running greenlet: context is stored in the thread state,
not the greenlet object. */
if (GET_THREAD_STATE().state().is_current(this->self())) {
result = PythonStateContext::context(PyThreadState_GET());
}
else {
throw ValueError(
"cannot get context of a "
"greenlet that is running in a different thread");
}
}
else {
/* Greenlet is not running: just return context. */
result = this->python_state.context();
}
if (!result) {
result = OwnedObject::None();
}
return result;
}
void
Greenlet::context(BorrowedObject given)
{
using greenlet::PythonStateContext;
if (!given) {
throw AttributeError("can't delete context attribute");
}
if (given.is_None()) {
/* "Empty context" is stored as NULL, not None. */
given = nullptr;
}
//checks type, incrs refcnt
greenlet::refs::OwnedContext context(given);
PyThreadState* tstate = PyThreadState_GET();
if (this->is_currently_running_in_some_thread()) {
if (!GET_THREAD_STATE().state().is_current(this->self())) {
throw ValueError("cannot set context of a greenlet"
" that is running in a different thread");
}
/* Currently running greenlet: context is stored in the thread state,
not the greenlet object. */
OwnedObject octx = OwnedObject::consuming(PythonStateContext::context(tstate));
PythonStateContext::context(tstate, context.relinquish_ownership());
}
else {
/* Greenlet is not running: just set context. Note that the
greenlet may be dead.*/
this->python_state.context() = context;
}
}
/**
* CAUTION: May invoke arbitrary Python code.
*
* Figure out what the result of ``greenlet.switch(arg, kwargs)``
* should be and transfers ownership of it to the left-hand-side.
*
* If switch() was just passed an arg tuple, then we'll just return that.
* If only keyword arguments were passed, then we'll pass the keyword
* argument dict. Otherwise, we'll create a tuple of (args, kwargs) and
* return both.
*
* CAUTION: This may allocate a new tuple object, which may
* cause the Python garbage collector to run, which in turn may
* run arbitrary Python code that switches.
*/
OwnedObject& operator<<=(OwnedObject& lhs, greenlet::SwitchingArgs& rhs) noexcept
{
// Because this may invoke arbitrary Python code, which could
// result in switching back to us, we need to get the
// arguments locally on the stack.
assert(rhs);
OwnedObject args = rhs.args();
OwnedObject kwargs = rhs.kwargs();
rhs.CLEAR();
// We shouldn't be called twice for the same switch.
assert(args || kwargs);
assert(!rhs);
if (!kwargs) {
lhs = args;
}
else if (!PyDict_Size(kwargs.borrow())) {
lhs = args;
}
else if (!PySequence_Length(args.borrow())) {
lhs = kwargs;
}
else {
// PyTuple_Pack allocates memory, may GC, may run arbitrary
// Python code.
lhs = OwnedObject::consuming(PyTuple_Pack(2, args.borrow(), kwargs.borrow()));
}
return lhs;
}
static OwnedObject
g_handle_exit(const OwnedObject& greenlet_result)
{
if (!greenlet_result && mod_globs->PyExc_GreenletExit.PyExceptionMatches()) {
/* catch and ignore GreenletExit */
PyErrFetchParam val;
// TODO: When we run on 3.12+ only (GREENLET_312), switch to the
// ``PyErr_GetRaisedException`` family of functions. The
// ``PyErr_Fetch`` family is deprecated on 3.12+, but is part
// of the stable ABI so it's not going anywhere.
PyErr_Fetch(PyErrFetchParam(), val, PyErrFetchParam());
if (!val) {
return OwnedObject::None();
}
return OwnedObject(val);
}
if (greenlet_result) {
// package the result into a 1-tuple
// PyTuple_Pack increments the reference of its arguments,
// so we always need to decref the greenlet result;
// the owner will do that.
return OwnedObject::consuming(PyTuple_Pack(1, greenlet_result.borrow()));
}
return OwnedObject();
}
/**
* May run arbitrary Python code.
*/
OwnedObject
Greenlet::g_switch_finish(const switchstack_result_t& err)
{
assert(err.the_new_current_greenlet == this);
ThreadState& state = *this->thread_state();
// Because calling the trace function could do arbitrary things,
// including switching away from this greenlet and then maybe
// switching back, we need to capture the arguments now so that
// they don't change.
OwnedObject result;
if (this->args()) {
result <<= this->args();
}
else {
assert(PyErr_Occurred());
}
assert(!this->args());
try {
// Our only caller handles the bad error case
assert(err.status >= 0);
assert(state.borrow_current() == this->self());
if (OwnedObject tracefunc = state.get_tracefunc()) {
assert(result || PyErr_Occurred());
g_calltrace(tracefunc,
result ? mod_globs->event_switch : mod_globs->event_throw,
err.origin_greenlet,
this->self());
}
// The above could have invoked arbitrary Python code, but
// it couldn't switch back to this object and *also*
// throw an exception, so the args won't have changed.
if (PyErr_Occurred()) {
// We get here if we fell of the end of the run() function
// raising an exception. The switch itself was
// successful, but the function raised.
// valgrind reports that memory allocated here can still
// be reached after a test run.
throw PyErrOccurred::from_current();
}
return result;
}
catch (const PyErrOccurred&) {
/* Turn switch errors into switch throws */
/* Turn trace errors into switch throws */
this->release_args();
throw;
}
}
void
Greenlet::g_calltrace(const OwnedObject& tracefunc,
const greenlet::refs::ImmortalEventName& event,
const BorrowedGreenlet& origin,
const BorrowedGreenlet& target)
{
PyErrPieces saved_exc;
try {
TracingGuard tracing_guard;
// TODO: We have saved the active exception (if any) that's
// about to be raised. In the 'throw' case, we could provide
// the exception to the tracefunction, which seems very helpful.
tracing_guard.CallTraceFunction(tracefunc, event, origin, target);
}
catch (const PyErrOccurred&) {
// In case of exceptions trace function is removed,
// and any existing exception is replaced with the tracing
// exception.
GET_THREAD_STATE().state().set_tracefunc(Py_None);
throw;
}
saved_exc.PyErrRestore();
assert(
(event == mod_globs->event_throw && PyErr_Occurred())
|| (event == mod_globs->event_switch && !PyErr_Occurred())
);
}
void
Greenlet::murder_in_place()
{
if (this->active()) {
assert(!this->is_currently_running_in_some_thread());
this->deactivate_and_free();
}
}
inline void
Greenlet::deactivate_and_free()
{
if (!this->active()) {
return;
}
// Throw away any saved stack.
this->stack_state = StackState();
assert(!this->stack_state.active());
// Throw away any Python references.
// We're holding a borrowed reference to the last
// frame we executed. Since we borrowed it, the
// normal traversal, clear, and dealloc functions
// ignore it, meaning it leaks. (The thread state
// object can't find it to clear it when that's
// deallocated either, because by definition if we
// got an object on this list, it wasn't
// running and the thread state doesn't have
// this frame.)
// So here, we *do* clear it.
this->python_state.tp_clear(true);
}
bool
Greenlet::belongs_to_thread(const ThreadState* thread_state) const
{
if (!this->thread_state() // not running anywhere, or thread
// exited
|| !thread_state) { // same, or there is no thread state.
return false;
}
return true;
}
void
Greenlet::deallocing_greenlet_in_thread(const ThreadState* current_thread_state)
{
/* Cannot raise an exception to kill the greenlet if
it is not running in the same thread! */
if (this->belongs_to_thread(current_thread_state)) {
assert(current_thread_state);
// To get here it had to have run before
/* Send the greenlet a GreenletExit exception. */
// We don't care about the return value, only whether an
// exception happened.
this->throw_GreenletExit_during_dealloc(*current_thread_state);
return;
}
// Not the same thread! Temporarily save the greenlet
// into its thread's deleteme list, *if* it exists.
// If that thread has already exited, and processed its pending
// cleanup, we'll never be able to clean everything up: we won't
// be able to raise an exception.
// That's mostly OK! Since we can't add it to a list, our refcount
// won't increase, and we'll go ahead with the DECREFs later.
ThreadState *const thread_state = this->thread_state();
if (thread_state) {
thread_state->delete_when_thread_running(this->self());
}
else {
// The thread is dead, we can't raise an exception.
// We need to make it look non-active, though, so that dealloc
// finishes killing it.
this->deactivate_and_free();
}
return;
}
int
Greenlet::tp_traverse(visitproc visit, void* arg)
{
int result;
if ((result = this->exception_state.tp_traverse(visit, arg)) != 0) {
return result;
}
//XXX: This is ugly. But so is handling everything having to do
//with the top frame.
bool visit_top_frame = this->was_running_in_dead_thread();
// When true, the thread is dead. Our implicit weak reference to the
// frame is now all that's left; we consider ourselves to
// strongly own it now.
if ((result = this->python_state.tp_traverse(visit, arg, visit_top_frame)) != 0) {
return result;
}
return 0;
}
int
Greenlet::tp_clear()
{
bool own_top_frame = this->was_running_in_dead_thread();
this->exception_state.tp_clear();
this->python_state.tp_clear(own_top_frame);
if (own_top_frame) {
// Throw away any saved stack state since the owned frame is cleared.
this->stack_state.set_inactive();
}
return 0;
}
bool Greenlet::is_currently_running_in_some_thread() const
{
return this->stack_state.active() && !this->python_state.top_frame();
}
#if GREENLET_PY312
void GREENLET_NOINLINE(Greenlet::expose_frames)()
{
if (!this->python_state.top_frame()) {
return;
}
_PyInterpreterFrame* last_complete_iframe = nullptr;
_PyInterpreterFrame* iframe = this->python_state.top_frame()->f_frame;
while (iframe) {
// We must make a copy before looking at the iframe contents,
// since iframe might point to a portion of the greenlet's C stack
// that was spilled when switching greenlets.
_PyInterpreterFrame iframe_copy;
this->stack_state.copy_from_stack(&iframe_copy, iframe, sizeof(*iframe));
if (!_PyFrame_IsIncomplete(&iframe_copy)) {
// If the iframe were OWNED_BY_CSTACK then it would always be
// incomplete. Since it's not incomplete, it's not on the C stack
// and we can access it through the original `iframe` pointer
// directly. This is important since GetFrameObject might
// lazily _create_ the frame object and we don't want the
// interpreter to lose track of it.
//
#if !GREENLET_PY315
// This enum value was removed in
// https://github.com/python/cpython/pull/141108
assert(iframe_copy.owner != FRAME_OWNED_BY_CSTACK);
#endif
// We really want to just write:
// PyFrameObject* frame = _PyFrame_GetFrameObject(iframe);
// but _PyFrame_GetFrameObject calls _PyFrame_MakeAndSetFrameObject
// which is not a visible symbol in libpython. The easiest
// way to get a public function to call it is using
// PyFrame_GetBack, which is defined as follows:
// assert(frame != NULL);
// assert(!_PyFrame_IsIncomplete(frame->f_frame));
// PyFrameObject *back = frame->f_back;
// if (back == NULL) {
// _PyInterpreterFrame *prev = frame->f_frame->previous;
// prev = _PyFrame_GetFirstComplete(prev);
// if (prev) {
// back = _PyFrame_GetFrameObject(prev);
// }
// }
// return (PyFrameObject*)Py_XNewRef(back);
if (!iframe->frame_obj) {
PyFrameObject dummy_frame;
_PyInterpreterFrame dummy_iframe;
dummy_frame.f_back = nullptr;
dummy_frame.f_frame = &dummy_iframe;
// force the iframe to be considered complete without
// needing to check its code object:
dummy_iframe.owner = FRAME_OWNED_BY_GENERATOR;
dummy_iframe.previous = iframe;
assert(!_PyFrame_IsIncomplete(&dummy_iframe));
// Drop the returned reference immediately; the iframe
// continues to hold a strong reference
Py_XDECREF(PyFrame_GetBack(&dummy_frame));
assert(iframe->frame_obj);
}
// This is a complete frame, so make the last one of those we saw
// point at it, bypassing any incomplete frames (which may have
// been on the C stack) in between the two. We're overwriting
// last_complete_iframe->previous and need that to be reversible,
// so we store the original previous ptr in the frame object
// (which we must have created on a previous iteration through
// this loop). The frame object has a bunch of storage that is
// only used when its iframe is OWNED_BY_FRAME_OBJECT, which only
// occurs when the frame object outlives the frame's execution,
// which can't have happened yet because the frame is currently
// executing as far as the interpreter is concerned. So, we can
// reuse it for our own purposes.
assert(iframe->owner == FRAME_OWNED_BY_THREAD
|| iframe->owner == FRAME_OWNED_BY_GENERATOR);
if (last_complete_iframe) {
assert(last_complete_iframe->frame_obj);
memcpy(&last_complete_iframe->frame_obj->_f_frame_data[0],
&last_complete_iframe->previous, sizeof(void *));
last_complete_iframe->previous = iframe;
}
last_complete_iframe = iframe;
}
// Frames that are OWNED_BY_FRAME_OBJECT are linked via the
// frame's f_back while all others are linked via the iframe's
// previous ptr. Since all the frames we traverse are running
// as far as the interpreter is concerned, we don't have to
// worry about the OWNED_BY_FRAME_OBJECT case.
iframe = iframe_copy.previous;
}
// Give the outermost complete iframe a null previous pointer to
// account for any potential incomplete/C-stack iframes between it
// and the actual top-of-stack
if (last_complete_iframe) {
assert(last_complete_iframe->frame_obj);
memcpy(&last_complete_iframe->frame_obj->_f_frame_data[0],
&last_complete_iframe->previous, sizeof(void *));
last_complete_iframe->previous = nullptr;
}
}
#else
void Greenlet::expose_frames()
{
}
#endif
}; // namespace greenlet
#endif

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venv/Lib/site-packages/greenlet/TGreenlet.hpp Normal file
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#ifndef GREENLET_GREENLET_HPP
#define GREENLET_GREENLET_HPP
/*
* Declarations of the core data structures.
*/
#define PY_SSIZE_T_CLEAN
#include <Python.h>
#include <atomic>
#include "greenlet_compiler_compat.hpp"
#include "greenlet_refs.hpp"
#include "greenlet_cpython_compat.hpp"
#include "greenlet_allocator.hpp"
using greenlet::refs::OwnedObject;
using greenlet::refs::OwnedGreenlet;
using greenlet::refs::OwnedMainGreenlet;
using greenlet::refs::BorrowedGreenlet;
#if PY_VERSION_HEX < 0x30B00A6
// prior to 3.11.0a6
# define _PyCFrame CFrame
# define _PyInterpreterFrame _interpreter_frame
#endif
#if GREENLET_PY312
# define Py_BUILD_CORE
# include "internal/pycore_frame.h"
#endif
#if GREENLET_PY314
# include "internal/pycore_interpframe_structs.h"
#if defined(_MSC_VER) || defined(__MINGW64__)
# include "greenlet_msvc_compat.hpp"
#else
# include "internal/pycore_interpframe.h"
#endif
#ifdef Py_GIL_DISABLED
# include "internal/pycore_tstate.h"
#endif
#endif
#if GREENLET_PY315
#include "internal/pycore_gc.h"
#if !defined(_MSC_VER) && !defined(__MINGW64__)
#include "internal/pycore_stackref.h"
#endif
#endif
// XXX: TODO: Work to remove all virtual functions
// for speed of calling and size of objects (no vtable).
// One pattern is the Curiously Recurring Template
namespace greenlet
{
class ExceptionState
{
private:
G_NO_COPIES_OF_CLS(ExceptionState);
// Even though these are borrowed objects, we actually own
// them, when they're not null.
// XXX: Express that in the API.
private:
_PyErr_StackItem* exc_info;
_PyErr_StackItem exc_state;
public:
ExceptionState();
void operator<<(const PyThreadState *const tstate) noexcept;
void operator>>(PyThreadState* tstate) noexcept;
void clear() noexcept;
int tp_traverse(visitproc visit, void* arg) noexcept;
void tp_clear() noexcept;
};
template<typename T>
void operator<<(const PyThreadState *const tstate, T& exc);
class PythonStateContext
{
protected:
greenlet::refs::OwnedContext _context;
public:
inline const greenlet::refs::OwnedContext& context() const
{
return this->_context;
}
inline greenlet::refs::OwnedContext& context()
{
return this->_context;
}
inline void tp_clear()
{
this->_context.CLEAR();
}
template<typename T>
inline static PyObject* context(T* tstate)
{
return tstate->context;
}
template<typename T>
inline static void context(T* tstate, PyObject* new_context)
{
tstate->context = new_context;
tstate->context_ver++;
}
};
class SwitchingArgs;
class PythonState : public PythonStateContext
{
public:
typedef greenlet::refs::OwnedReference<struct _frame> OwnedFrame;
private:
G_NO_COPIES_OF_CLS(PythonState);
// We own this if we're suspended (although currently we don't
// tp_traverse into it; that's a TODO). If we're running, it's
// empty. If we get deallocated and *still* have a frame, it
// won't be reachable from the place that normally decref's
// it, so we need to do it (hence owning it).
OwnedFrame _top_frame;
#if GREENLET_USE_CFRAME
_PyCFrame* cframe;
int use_tracing;
#endif
#if GREENLET_PY314
int py_recursion_depth;
// I think this is only used by the JIT. At least,
// we only got errors not switching it when the JIT was enabled.
// Python/generated_cases.c.h:12469: _PyEval_EvalFrameDefault:
// Assertion `tstate->current_executor == NULL' failed.
// see https://github.com/python-greenlet/greenlet/issues/460
PyObject* current_executor;
_PyStackRef* stackpointer;
#ifdef Py_GIL_DISABLED
_PyCStackRef* c_stack_refs;
#endif
#elif GREENLET_PY312
int py_recursion_depth;
int c_recursion_depth;
#else
int recursion_depth;
#endif
#if GREENLET_PY313
PyObject* delete_later;
uintptr_t critical_section;
#else
int trash_delete_nesting;
#endif
#if GREENLET_PY311
_PyInterpreterFrame* current_frame;
_PyStackChunk* datastack_chunk;
PyObject** datastack_top;
PyObject** datastack_limit;
#endif
// The PyInterpreterFrame list on 3.12+ contains some entries that are
// on the C stack, which can't be directly accessed while a greenlet is
// suspended. In order to keep greenlet gr_frame introspection working,
// we adjust stack switching to rewrite the interpreter frame list
// to skip these C-stack frames; we call this "exposing" the greenlet's
// frames because it makes them valid to work with in Python. Then when
// the greenlet is resumed we need to remember to reverse the operation
// we did. The C-stack frames are "entry frames" which are a low-level
// interpreter detail; they're not needed for introspection, but do
// need to be present for the eval loop to work.
void unexpose_frames();
public:
PythonState();
// You can use this for testing whether we have a frame
// or not. It returns const so they can't modify it.
const OwnedFrame& top_frame() const noexcept;
inline void operator<<(const PyThreadState *const tstate) noexcept;
inline void operator>>(PyThreadState* tstate) noexcept;
void clear() noexcept;
int tp_traverse(visitproc visit, void* arg, bool visit_top_frame) noexcept;
void tp_clear(bool own_top_frame) noexcept;
void set_initial_state(const PyThreadState* const tstate) noexcept;
#if GREENLET_USE_CFRAME
void set_new_cframe(_PyCFrame& frame) noexcept;
#endif
void may_switch_away() noexcept;
inline void will_switch_from(PyThreadState *const origin_tstate) noexcept;
void did_finish(PyThreadState* tstate) noexcept;
};
class StackState
{
// By having only plain C (POD) members, no virtual functions
// or bases, we get a trivial assignment operator generated
// for us. However, that's not safe since we do manage memory.
// So we declare an assignment operator that only works if we
// don't have any memory allocated. (We don't use
// std::shared_ptr for reference counting just to keep this
// object small)
private:
char* _stack_start;
char* stack_stop;
char* stack_copy;
intptr_t _stack_saved;
StackState* stack_prev;
inline int copy_stack_to_heap_up_to(const char* const stop) noexcept;
inline void free_stack_copy() noexcept;
public:
/**
* Creates a started, but inactive, state, using *current*
* as the previous.
*/
StackState(void* mark, StackState& current);
/**
* Creates an inactive, unstarted, state.
*/
StackState();
~StackState();
StackState(const StackState& other);
StackState& operator=(const StackState& other);
inline void copy_heap_to_stack(const StackState& current) noexcept;
inline int copy_stack_to_heap(char* const stackref, const StackState& current) noexcept;
inline bool started() const noexcept;
inline bool main() const noexcept;
inline bool active() const noexcept;
inline void set_active() noexcept;
inline void set_inactive() noexcept;
inline intptr_t stack_saved() const noexcept;
inline char* stack_start() const noexcept;
static inline StackState make_main() noexcept;
#ifdef GREENLET_USE_STDIO
friend std::ostream& operator<<(std::ostream& os, const StackState& s);
#endif
// Fill in [dest, dest + n) with the values that would be at
// [src, src + n) while this greenlet is running. This is like memcpy
// except that if the greenlet is suspended it accounts for the portion
// of the greenlet's stack that was spilled to the heap. `src` may
// be on this greenlet's stack, or on the heap, but not on a different
// greenlet's stack.
void copy_from_stack(void* dest, const void* src, size_t n) const;
};
#ifdef GREENLET_USE_STDIO
std::ostream& operator<<(std::ostream& os, const StackState& s);
#endif
class SwitchingArgs
{
private:
G_NO_ASSIGNMENT_OF_CLS(SwitchingArgs);
// If args and kwargs are both false (NULL), this is a *throw*, not a
// switch. PyErr_... must have been called already.
OwnedObject _args;
OwnedObject _kwargs;
public:
SwitchingArgs()
{}
SwitchingArgs(const OwnedObject& args, const OwnedObject& kwargs)
: _args(args),
_kwargs(kwargs)
{}
SwitchingArgs(const SwitchingArgs& other)
: _args(other._args),
_kwargs(other._kwargs)
{}
const OwnedObject& args()
{
return this->_args;
}
const OwnedObject& kwargs()
{
return this->_kwargs;
}
/**
* Moves ownership from the argument to this object.
*/
SwitchingArgs& operator<<=(SwitchingArgs& other)
{
if (this != &other) {
this->_args = other._args;
this->_kwargs = other._kwargs;
other.CLEAR();
}
return *this;
}
/**
* Acquires ownership of the argument (consumes the reference).
*/
SwitchingArgs& operator<<=(PyObject* args)
{
this->_args = OwnedObject::consuming(args);
this->_kwargs.CLEAR();
return *this;
}
/**
* Acquires ownership of the argument.
*
* Sets the args to be the given value; clears the kwargs.
*/
SwitchingArgs& operator<<=(OwnedObject& args)
{
assert(&args != &this->_args);
this->_args = args;
this->_kwargs.CLEAR();
args.CLEAR();
return *this;
}
explicit operator bool() const noexcept
{
return this->_args || this->_kwargs;
}
inline void CLEAR()
{
this->_args.CLEAR();
this->_kwargs.CLEAR();
}
const std::string as_str() const noexcept
{
return PyUnicode_AsUTF8(
OwnedObject::consuming(
PyUnicode_FromFormat(
"SwitchingArgs(args=%R, kwargs=%R)",
this->_args.borrow(),
this->_kwargs.borrow()
)
).borrow()
);
}
};
class ThreadState;
class UserGreenlet;
class MainGreenlet;
class Greenlet
{
private:
G_NO_COPIES_OF_CLS(Greenlet);
PyGreenlet* const _self;
private:
// XXX: Work to remove these.
friend class ThreadState;
friend class UserGreenlet;
friend class MainGreenlet;
protected:
ExceptionState exception_state;
SwitchingArgs switch_args;
StackState stack_state;
PythonState python_state;
Greenlet(PyGreenlet* p, const StackState& initial_state);
public:
// This constructor takes ownership of the PyGreenlet, by
// setting ``p->pimpl = this;``.
Greenlet(PyGreenlet* p);
virtual ~Greenlet();
const OwnedObject context() const;
// You MUST call this _very_ early in the switching process to
// prepare anything that may need prepared. This might perform
// garbage collections or otherwise run arbitrary Python code.
//
// One specific use of it is for Python 3.11+, preventing
// running arbitrary code at unsafe times. See
// PythonState::may_switch_away().
inline void may_switch_away()
{
this->python_state.may_switch_away();
}
inline void context(refs::BorrowedObject new_context);
inline SwitchingArgs& args()
{
return this->switch_args;
}
virtual const refs::BorrowedMainGreenlet main_greenlet() const = 0;
inline intptr_t stack_saved() const noexcept
{
return this->stack_state.stack_saved();
}
// This is used by the macro SLP_SAVE_STATE to compute the
// difference in stack sizes. It might be nice to handle the
// computation ourself, but the type of the result
// varies by platform, so doing it in the macro is the
// simplest way.
inline const char* stack_start() const noexcept
{
return this->stack_state.stack_start();
}
virtual OwnedObject throw_GreenletExit_during_dealloc(const ThreadState& current_thread_state);
/**
* Depends on the state of this->args() or the current Python
* error indicator. Thus, it is not threadsafe or reentrant.
* You (you being ``green_switch``, the Python-level
* ``greenlet.switch`` method) should call
* ``check_switch_allowed`` in free-threaded builds before
* calling this method and catch ``PyErrOccurred`` if it isn't
* a valid switch. This method should also call that method
* because there are places where we can switch internally
* without going through the Python method.
*/
virtual OwnedObject g_switch() = 0;
/**
* Force the greenlet to appear dead. Used when it's not
* possible to throw an exception into a greenlet anymore.
*
* This losses access to the thread state and the main greenlet.
*/
virtual void murder_in_place();
/**
* Called when somebody notices we were running in a dead
* thread to allow cleaning up resources (because we can't
* raise GreenletExit into it anymore).
* This is very similar to ``murder_in_place()``, except that
* it DOES NOT lose the main greenlet or thread state.
*/
inline void deactivate_and_free();
// Called when some thread wants to deallocate a greenlet
// object.
// The thread may or may not be the same thread the greenlet
// was running in.
// The thread state will be null if the thread the greenlet
// was running in was known to have exited.
void deallocing_greenlet_in_thread(const ThreadState* current_state);
// Must be called on 3.12+ before exposing a suspended greenlet's
// frames to user code. This rewrites the linked list of interpreter
// frames to skip the ones that are being stored on the C stack (which
// can't be safely accessed while the greenlet is suspended because
// that stack space might be hosting a different greenlet), and
// sets PythonState::frames_were_exposed so we remember to restore
// the original list before resuming the greenlet. The C-stack frames
// are a low-level interpreter implementation detail; while they're
// important to the bytecode eval loop, they're superfluous for
// introspection purposes.
void expose_frames();
// TODO: Figure out how to make these non-public.
inline void slp_restore_state() noexcept;
inline int slp_save_state(char *const stackref) noexcept;
inline bool is_currently_running_in_some_thread() const;
virtual bool belongs_to_thread(const ThreadState* state) const;
inline bool started() const
{
return this->stack_state.started();
}
inline bool active() const
{
return this->stack_state.active();
}
inline bool main() const
{
return this->stack_state.main();
}
virtual refs::BorrowedMainGreenlet find_main_greenlet_in_lineage() const = 0;
virtual const OwnedGreenlet parent() const = 0;
virtual void parent(const refs::BorrowedObject new_parent) = 0;
inline const PythonState::OwnedFrame& top_frame()
{
return this->python_state.top_frame();
}
virtual const OwnedObject& run() const = 0;
virtual void run(const refs::BorrowedObject nrun) = 0;
virtual int tp_traverse(visitproc visit, void* arg);
virtual int tp_clear();
// Return the thread state that the greenlet is running in, or
// null if the greenlet is not running or the thread is known
// to have exited.
virtual ThreadState* thread_state() const noexcept = 0;
// Return true if the greenlet is known to have been running
// (active) in a thread that has now exited.
virtual bool was_running_in_dead_thread() const noexcept = 0;
// Return a borrowed greenlet that is the Python object
// this object represents.
inline BorrowedGreenlet self() const noexcept
{
return BorrowedGreenlet(this->_self);
}
// For testing. If this returns true, we should pretend that
// slp_switch() failed.
virtual bool force_slp_switch_error() const noexcept;
// Check the preconditions for switching to this greenlet; if they
// aren't met, throws PyErrOccurred. Most callers will want to
// catch this and clear the arguments if they've been set.
inline void check_switch_allowed() const;
protected:
inline void release_args();
// The functions that must not be inlined are declared virtual.
// We also mark them as protected, not private, so that the
// compiler is forced to call them through a function pointer.
// (A sufficiently smart compiler could directly call a private
// virtual function since it can never be overridden in a
// subclass).
// Also TODO: Switch away from integer error codes and to enums,
// or throw exceptions when possible.
struct switchstack_result_t
{
int status;
Greenlet* the_new_current_greenlet;
OwnedGreenlet origin_greenlet;
switchstack_result_t()
: status(0),
the_new_current_greenlet(nullptr)
{}
switchstack_result_t(int err)
: status(err),
the_new_current_greenlet(nullptr)
{}
switchstack_result_t(int err, Greenlet* state, OwnedGreenlet& origin)
: status(err),
the_new_current_greenlet(state),
origin_greenlet(origin)
{
}
switchstack_result_t(int err, Greenlet* state, const BorrowedGreenlet& origin)
: status(err),
the_new_current_greenlet(state),
origin_greenlet(origin)
{
}
switchstack_result_t(const switchstack_result_t& other)
: status(other.status),
the_new_current_greenlet(other.the_new_current_greenlet),
origin_greenlet(other.origin_greenlet)
{}
switchstack_result_t& operator=(const switchstack_result_t& other)
{
this->status = other.status;
this->the_new_current_greenlet = other.the_new_current_greenlet;
this->origin_greenlet = other.origin_greenlet;
return *this;
}
};
OwnedObject on_switchstack_or_initialstub_failure(
Greenlet* target,
const switchstack_result_t& err,
const bool target_was_me=false,
const bool was_initial_stub=false);
// Returns the previous greenlet we just switched away from.
virtual OwnedGreenlet g_switchstack_success() noexcept;
class GreenletStartedWhileInPython : public std::runtime_error
{
public:
GreenletStartedWhileInPython() : std::runtime_error("")
{}
};
protected:
/**
Perform a stack switch into this greenlet.
This temporarily sets the global variable
``switching_thread_state`` to this greenlet; as soon as the
call to ``slp_switch`` completes, this is reset to NULL.
Consequently, this depends on the GIL.
TODO: Adopt the stackman model and pass ``slp_switch`` a
callback function and context pointer; this eliminates the
need for global variables altogether.
Because the stack switch happens in this function, this
function can't use its own stack (local) variables, set
before the switch, and then accessed after the switch.
Further, you con't even access ``g_thread_state_global``
before and after the switch from the global variable.
Because it is thread local some compilers cache it in a
register/on the stack, notably new versions of MSVC; this
breaks with strange crashes sometime later, because writing
to anything in ``g_thread_state_global`` after the switch
is actually writing to random memory. For this reason, we
call a non-inlined function to finish the operation. (XXX:
The ``/GT`` MSVC compiler argument probably fixes that.)
It is very important that stack switch is 'atomic', i.e. no
calls into other Python code allowed (except very few that
are safe), because global variables are very fragile. (This
should no longer be the case with thread-local variables.)
*/
// Made virtual to facilitate subclassing UserGreenlet for testing.
virtual switchstack_result_t g_switchstack(void);
class TracingGuard
{
private:
PyThreadState* tstate;
public:
TracingGuard()
: tstate(PyThreadState_GET())
{
PyThreadState_EnterTracing(this->tstate);
}
~TracingGuard()
{
PyThreadState_LeaveTracing(this->tstate);
this->tstate = nullptr;
}
inline void CallTraceFunction(const OwnedObject& tracefunc,
const greenlet::refs::ImmortalEventName& event,
const BorrowedGreenlet& origin,
const BorrowedGreenlet& target)
{
// TODO: This calls tracefunc(event, (origin, target)). Add a shortcut
// function for that that's specialized to avoid the Py_BuildValue
// string parsing, or start with just using "ON" format with PyTuple_Pack(2,
// origin, target). That seems like what the N format is meant
// for.
// XXX: Why does event not automatically cast back to a PyObject?
// It tries to call the "deleted constructor ImmortalEventName
// const" instead.
assert(tracefunc);
assert(event);
assert(origin);
assert(target);
greenlet::refs::NewReference retval(
PyObject_CallFunction(
tracefunc.borrow(),
"O(OO)",
event.borrow(),
origin.borrow(),
target.borrow()
));
if (!retval) {
throw PyErrOccurred::from_current();
}
}
};
static void
g_calltrace(const OwnedObject& tracefunc,
const greenlet::refs::ImmortalEventName& event,
const greenlet::refs::BorrowedGreenlet& origin,
const BorrowedGreenlet& target);
private:
OwnedObject g_switch_finish(const switchstack_result_t& err);
};
class UserGreenlet : public Greenlet
{
private:
static greenlet::PythonAllocator<UserGreenlet> allocator;
OwnedMainGreenlet _main_greenlet;
OwnedObject _run_callable;
OwnedGreenlet _parent;
public:
static void* operator new(size_t UNUSED(count));
static void operator delete(void* ptr);
UserGreenlet(PyGreenlet* p, BorrowedGreenlet the_parent);
virtual ~UserGreenlet();
virtual refs::BorrowedMainGreenlet find_main_greenlet_in_lineage() const;
virtual bool was_running_in_dead_thread() const noexcept;
virtual ThreadState* thread_state() const noexcept;
virtual OwnedObject g_switch();
virtual const OwnedObject& run() const
{
if (this->started() || !this->_run_callable) {
throw AttributeError("run");
}
return this->_run_callable;
}
virtual void run(const refs::BorrowedObject nrun);
virtual const OwnedGreenlet parent() const;
virtual void parent(const refs::BorrowedObject new_parent);
virtual const refs::BorrowedMainGreenlet main_greenlet() const;
virtual void murder_in_place();
virtual bool belongs_to_thread(const ThreadState* state) const;
virtual int tp_traverse(visitproc visit, void* arg);
virtual int tp_clear();
class ParentIsCurrentGuard
{
private:
OwnedGreenlet oldparent;
UserGreenlet* greenlet;
G_NO_COPIES_OF_CLS(ParentIsCurrentGuard);
public:
ParentIsCurrentGuard(UserGreenlet* p, const ThreadState& thread_state);
~ParentIsCurrentGuard();
};
virtual OwnedObject throw_GreenletExit_during_dealloc(const ThreadState& current_thread_state);
protected:
virtual switchstack_result_t g_initialstub(void* mark);
private:
// This function isn't meant to return.
// This accepts raw pointers and the ownership of them at the
// same time. The caller should use ``inner_bootstrap(origin.relinquish_ownership())``.
void inner_bootstrap(PyGreenlet* origin_greenlet, PyObject* run);
};
class BrokenGreenlet : public UserGreenlet
{
private:
static greenlet::PythonAllocator<BrokenGreenlet> allocator;
public:
bool _force_switch_error = false;
bool _force_slp_switch_error = false;
static void* operator new(size_t UNUSED(count));
static void operator delete(void* ptr);
BrokenGreenlet(PyGreenlet* p, BorrowedGreenlet the_parent)
: UserGreenlet(p, the_parent)
{}
virtual ~BrokenGreenlet()
{}
virtual switchstack_result_t g_switchstack(void);
virtual bool force_slp_switch_error() const noexcept;
};
class MainGreenlet : public Greenlet
{
private:
static greenlet::PythonAllocator<MainGreenlet> allocator;
refs::BorrowedMainGreenlet _self;
std::atomic<ThreadState*> _thread_state;
G_NO_COPIES_OF_CLS(MainGreenlet);
public:
static void* operator new(size_t UNUSED(count));
static void operator delete(void* ptr);
MainGreenlet(refs::BorrowedMainGreenlet::PyType*, ThreadState*);
virtual ~MainGreenlet();
virtual const OwnedObject& run() const;
virtual void run(const refs::BorrowedObject nrun);
virtual const OwnedGreenlet parent() const;
virtual void parent(const refs::BorrowedObject new_parent);
virtual const refs::BorrowedMainGreenlet main_greenlet() const;
virtual refs::BorrowedMainGreenlet find_main_greenlet_in_lineage() const;
virtual bool was_running_in_dead_thread() const noexcept;
virtual ThreadState* thread_state() const noexcept;
void thread_state(ThreadState*) noexcept;
virtual OwnedObject g_switch();
virtual int tp_traverse(visitproc visit, void* arg);
};
// Instantiate one on the stack to save the GC state,
// and then disable GC. When it goes out of scope, GC will be
// restored to its original state.
class GCDisabledGuard
{
private:
int was_enabled = 0;
public:
GCDisabledGuard()
: was_enabled(PyGC_IsEnabled())
{
PyGC_Disable();
}
~GCDisabledGuard()
{
if (this->was_enabled) {
PyGC_Enable();
}
}
};
OwnedObject& operator<<=(OwnedObject& lhs, greenlet::SwitchingArgs& rhs) noexcept;
//TODO: Greenlet::g_switch() should call this automatically on its
//return value. As it is, the module code is calling it.
static inline OwnedObject
single_result(const OwnedObject& results)
{
if (results
&& PyTuple_Check(results.borrow())
&& PyTuple_GET_SIZE(results.borrow()) == 1) {
PyObject* result = PyTuple_GET_ITEM(results.borrow(), 0);
assert(result);
return OwnedObject::owning(result);
}
return results;
}
static OwnedObject
g_handle_exit(const OwnedObject& greenlet_result);
template<typename T>
void operator<<(const PyThreadState *const lhs, T& rhs)
{
rhs.operator<<(lhs);
}
} // namespace greenlet ;
#endif

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venv/Lib/site-packages/greenlet/TGreenletGlobals.cpp Normal file
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/* -*- 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 <algorithm>
#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.)
}
/**
* Must be holding the ``thread_states_to_destroy`` lock.
*/
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);
// make sure we don't ever try to clean up a state more than
// once. Because they're thread-local, and we ultimately call this
// method from the destructor of the thread local variable,
// we should never find the item already present. This check
// is nominally O(n) in the size of the vector.
assert(std::find(q.begin(), q.end(), ts) == q.end());
q.push_back(ts);
}
/**
* Must be holding the ``thread_states_to_destroy`` lock.
*/
ThreadState* take_next_to_destroy() const
{
greenlet::cleanup_queue_t& q = const_cast<greenlet::cleanup_queue_t&>(
this->thread_states_to_destroy);
if (q.empty()) {
return nullptr;
}
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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venv/Lib/site-packages/greenlet/TMainGreenlet.cpp Normal file
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/* -*- indent-tabs-mode: nil; tab-width: 4; -*- */
/**
* Implementation of greenlet::MainGreenlet.
*
* 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_MAIN_GREENLET_CPP
#define T_MAIN_GREENLET_CPP
#include "TGreenlet.hpp"
#ifdef Py_GIL_DISABLED
#include <atomic>
#endif
// Incremented when we create a main greenlet, in a new thread, decremented
// when it is destroyed.
#ifdef Py_GIL_DISABLED
static std::atomic<Py_ssize_t> G_TOTAL_MAIN_GREENLETS(0);
#else
// Protected by the GIL.
static Py_ssize_t G_TOTAL_MAIN_GREENLETS;
#endif
namespace greenlet {
greenlet::PythonAllocator<MainGreenlet> MainGreenlet::allocator;
void* MainGreenlet::operator new(size_t UNUSED(count))
{
return allocator.allocate(1);
}
void MainGreenlet::operator delete(void* ptr)
{
return allocator.deallocate(static_cast<MainGreenlet*>(ptr),
1);
}
MainGreenlet::MainGreenlet(PyGreenlet* p, ThreadState* state)
: Greenlet(p, StackState::make_main()),
_self(p),
_thread_state(state)
{
G_TOTAL_MAIN_GREENLETS++;
}
MainGreenlet::~MainGreenlet()
{
G_TOTAL_MAIN_GREENLETS--;
this->tp_clear();
}
ThreadState*
MainGreenlet::thread_state() const noexcept
{
return this->_thread_state;
}
void
MainGreenlet::thread_state(ThreadState* t) noexcept
{
// this method is only used during thread tear down, when it is
// called with nullptr, signalling the thread is dead.
assert(!t);
this->_thread_state = t;
}
const BorrowedMainGreenlet
MainGreenlet::main_greenlet() const
{
return this->_self;
}
BorrowedMainGreenlet
MainGreenlet::find_main_greenlet_in_lineage() const
{
return BorrowedMainGreenlet(this->_self);
}
bool
MainGreenlet::was_running_in_dead_thread() const noexcept
{
return !this->_thread_state;
}
OwnedObject
MainGreenlet::g_switch()
{
try {
this->check_switch_allowed();
}
catch (const PyErrOccurred&) {
this->release_args();
throw;
}
switchstack_result_t err = this->g_switchstack();
if (err.status < 0) {
// XXX: This code path is untested, but it is shared
// with the UserGreenlet path that is tested.
return this->on_switchstack_or_initialstub_failure(
this,
err,
true, // target was me
false // was initial stub
);
}
return err.the_new_current_greenlet->g_switch_finish(err);
}
int
MainGreenlet::tp_traverse(visitproc visit, void* arg)
{
ThreadState* thread_state = this->_thread_state.load();
if (thread_state) {
// we've already traversed main, (self), don't do it again.
int result = thread_state->tp_traverse(visit, arg, false);
if (result) {
return result;
}
}
return Greenlet::tp_traverse(visit, arg);
}
const OwnedObject&
MainGreenlet::run() const
{
throw AttributeError("Main greenlets do not have a run attribute.");
}
void
MainGreenlet::run(const BorrowedObject UNUSED(nrun))
{
throw AttributeError("Main greenlets do not have a run attribute.");
}
void
MainGreenlet::parent(const BorrowedObject raw_new_parent)
{
if (!raw_new_parent) {
throw AttributeError("can't delete attribute");
}
throw AttributeError("cannot set the parent of a main greenlet");
}
const OwnedGreenlet
MainGreenlet::parent() const
{
return OwnedGreenlet(); // null becomes None
}
}; // namespace greenlet
#endif