#define _PY_INTERPRETER

#include "Python.h"

#include "pycore_frame.h"         // _PyFrame_New_NoTrack()

#include "pycore_interpframe.h"   // _PyFrame_GetCode()

#include "pycore_genobject.h"     // _PyGen_GetGeneratorFromFrame()

#include "pycore_stackref.h"      // _Py_VISIT_STACKREF()

int

_PyFrame_Traverse(_PyInterpreterFrame *frame, visitproc visit, void *arg)

{

    Py_VISIT(frame->frame_obj);

    Py_VISIT(frame->f_locals);

    _Py_VISIT_STACKREF(frame->f_funcobj);

    _Py_VISIT_STACKREF(frame->f_executable);

    return _PyGC_VisitFrameStack(frame, visit, arg);

}

PyFrameObject *

_PyFrame_MakeAndSetFrameObject(_PyInterpreterFrame *frame)

{

    assert(frame->frame_obj == NULL);

    PyObject *exc = PyErr_GetRaisedException();

    PyFrameObject *f = _PyFrame_New_NoTrack(_PyFrame_GetCode(frame));

    if (f == NULL) {

        Py_XDECREF(exc);

        return NULL;

    }

    PyErr_SetRaisedException(exc);

    // GH-97002: There was a time when a frame object could be created when we

    // are allocating the new frame object f above, so frame->frame_obj would

    // be assigned already. That path does not exist anymore. We won't call any

    // Python code in this function and garbage collection will not run.

    // Notice that _PyFrame_New_NoTrack() can potentially raise a MemoryError,

    // but it won't allocate a traceback until the frame unwinds, so we are safe

    // here.

    assert(frame->frame_obj == NULL);

    assert(frame->owner != FRAME_OWNED_BY_FRAME_OBJECT);

    f->f_frame = frame;

    frame->frame_obj = f;

    return f;

}

static void

take_ownership(PyFrameObject *f, _PyInterpreterFrame *frame)

{

    Py_BEGIN_CRITICAL_SECTION(f);

    assert(frame->owner < FRAME_OWNED_BY_INTERPRETER);

    assert(frame->owner != FRAME_OWNED_BY_FRAME_OBJECT);

    _PyInterpreterFrame *new_frame = (_PyInterpreterFrame *)f->_f_frame_data;

    _PyFrame_Copy(frame, new_frame);

    // _PyFrame_Copy takes the reference to the executable,

    // so we need to restore it.

    frame->f_executable = PyStackRef_DUP(new_frame->f_executable);

    f->f_frame = new_frame;

    new_frame->owner = FRAME_OWNED_BY_FRAME_OBJECT;

    if (_PyFrame_IsIncomplete(new_frame)) {

        // This may be a newly-created generator or coroutine frame. Since it's

        // dead anyways, just pretend that the first RESUME ran:

        PyCodeObject *code = _PyFrame_GetCode(new_frame);

        new_frame->instr_ptr =

            _PyFrame_GetBytecode(new_frame) + code->_co_firsttraceable + 1;

    }

    assert(!_PyFrame_IsIncomplete(new_frame));

    assert(f->f_back == NULL);

    _PyInterpreterFrame *prev = _PyFrame_GetFirstComplete(frame->previous);

    if (prev) {

        assert(prev->owner < FRAME_OWNED_BY_INTERPRETER);

        PyObject *exc = PyErr_GetRaisedException();

        /* Link PyFrameObjects.f_back and remove link through _PyInterpreterFrame.previous */

        PyFrameObject *back = _PyFrame_GetFrameObject(prev);

        if (back == NULL) {

            /* Memory error here. */

            assert(PyErr_ExceptionMatches(PyExc_MemoryError));

            /* Nothing we can do about it */

            PyErr_Clear();

        }

        else {

            f->f_back = (PyFrameObject *)Py_NewRef(back);

        }

        PyErr_SetRaisedException(exc);

    }

    if (!_PyObject_GC_IS_TRACKED((PyObject *)f)) {

        _PyObject_GC_TRACK((PyObject *)f);

    }

    Py_END_CRITICAL_SECTION();

}

void

_PyFrame_ClearLocals(_PyInterpreterFrame *frame)

{

    assert(frame->stackpointer != NULL);

    _PyStackRef *sp = frame->stackpointer;

    _PyStackRef *locals = frame->localsplus;

    frame->stackpointer = locals;

    while (sp > locals) {

        sp--;

        PyStackRef_XCLOSE(*sp);

    }

    Py_CLEAR(frame->f_locals);

}

void

_PyFrame_ClearExceptCode(_PyInterpreterFrame *frame)

{

    /* It is the responsibility of the owning generator/coroutine

     * to have cleared the enclosing generator, if any. */

    assert(frame->owner != FRAME_OWNED_BY_GENERATOR ||

        _PyGen_GetGeneratorFromFrame(frame)->gi_frame_state == FRAME_CLEARED);

    // GH-99729: Clearing this frame can expose the stack (via finalizers). It's

    // crucial that this frame has been unlinked, and is no longer visible:

    assert(_PyThreadState_GET()->current_frame != frame);

    if (frame->frame_obj) {

        PyFrameObject *f = frame->frame_obj;

        frame->frame_obj = NULL;

        if (!_PyObject_IsUniquelyReferenced((PyObject *)f)) {

            take_ownership(f, frame);

            Py_DECREF(f);

            return;

        }

        Py_DECREF(f);

    }

    _PyFrame_ClearLocals(frame);

    PyStackRef_CLEAR(frame->f_funcobj);

}

/* Unstable API functions */

PyObject *

PyUnstable_InterpreterFrame_GetCode(struct _PyInterpreterFrame *frame)

{

    return PyStackRef_AsPyObjectNew(frame->f_executable);

}

int

PyUnstable_InterpreterFrame_GetLasti(struct _PyInterpreterFrame *frame)

{

    return _PyInterpreterFrame_LASTI(frame) * sizeof(_Py_CODEUNIT);

}

// NOTE: We allow racy accesses to the instruction pointer from other threads

// for sys._current_frames() and similar APIs.

int _Py_NO_SANITIZE_THREAD

PyUnstable_InterpreterFrame_GetLine(_PyInterpreterFrame *frame)

{

    int addr = _PyInterpreterFrame_LASTI(frame) * sizeof(_Py_CODEUNIT);

    return PyCode_Addr2Line(_PyFrame_GetCode(frame), addr);

}

const PyTypeObject *const PyUnstable_ExecutableKinds[PyUnstable_EXECUTABLE_KINDS+1] = {

    [PyUnstable_EXECUTABLE_KIND_SKIP] = &_PyNone_Type,

    [PyUnstable_EXECUTABLE_KIND_PY_FUNCTION] = &PyCode_Type,

    [PyUnstable_EXECUTABLE_KIND_BUILTIN_FUNCTION] = &PyMethod_Type,

    [PyUnstable_EXECUTABLE_KIND_METHOD_DESCRIPTOR] = &PyMethodDescr_Type,

    [PyUnstable_EXECUTABLE_KINDS] = NULL,

};