#ifndef Py_CPYTHON_PYSTATE_H
# error "this header file must not be included directly"
#endif

#ifdef __cplusplus
extern "C" {
#endif

#include "cpython/initconfig.h"

PyAPI_FUNC(int) _PyInterpreterState_RequiresIDRef(PyInterpreterState *);
PyAPI_FUNC(void) _PyInterpreterState_RequireIDRef(PyInterpreterState *, int);

PyAPI_FUNC(PyObject *) _PyInterpreterState_GetMainModule(PyInterpreterState *);

/* State unique per thread */

/* Py_tracefunc return -1 when raising an exception, or 0 for success. */
typedef int (*Py_tracefunc)(PyObject *, struct _frame *, int, PyObject *);

/* The following values are used for 'what' for tracefunc functions
 *
 * To add a new kind of trace event, also update "trace_init" in
 * Python/sysmodule.c to define the Python level event name
 */
#define PyTrace_CALL 0
#define PyTrace_EXCEPTION 1
#define PyTrace_LINE 2
#define PyTrace_RETURN 3
#define PyTrace_C_CALL 4
#define PyTrace_C_EXCEPTION 5
#define PyTrace_C_RETURN 6
#define PyTrace_OPCODE 7


typedef struct _err_stackitem {
 /* This struct represents an entry on the exception stack, which is a
 * per-coroutine state. (Coroutine in the computer science sense,
 * including the thread and generators).
 * This ensures that the exception state is not impacted by "yields"
 * from an except handler.
 */
 PyObject *exc_type, *exc_value, *exc_traceback;

 struct _err_stackitem *previous_item;

} _PyErr_StackItem;


// The PyThreadState typedef is in Include/pystate.h.
struct _ts {
 /* See Python/ceval.c for comments explaining most fields */

 struct _ts *prev;
 struct _ts *next;
 PyInterpreterState *interp;

 /* Borrowed reference to the current frame (it can be NULL) */
 struct _frame *frame;
 int recursion_depth;
 char overflowed; /* The stack has overflowed. Allow 50 more calls
 to handle the runtime error. */
 char recursion_critical; /* The current calls must not cause
 a stack overflow. */
 int stackcheck_counter;

 /* 'tracing' keeps track of the execution depth when tracing/profiling.
 This is to prevent the actual trace/profile code from being recorded in
 the trace/profile. */
 int tracing;
 int use_tracing;

 Py_tracefunc c_profilefunc;
 Py_tracefunc c_tracefunc;
 PyObject *c_profileobj;
 PyObject *c_traceobj;

 /* The exception currently being raised */
 PyObject *curexc_type;
 PyObject *curexc_value;
 PyObject *curexc_traceback;

 /* The exception currently being handled, if no coroutines/generators
 * are present. Always last element on the stack referred to be exc_info.
 */
 _PyErr_StackItem exc_state;

 /* Pointer to the top of the stack of the exceptions currently
 * being handled */
 _PyErr_StackItem *exc_info;

 PyObject *dict; /* Stores per-thread state */

 int gilstate_counter;

 PyObject *async_exc; /* Asynchronous exception to raise */
 unsigned long thread_id; /* Thread id where this tstate was created */

 int trash_delete_nesting;
 PyObject *trash_delete_later;

 /* Called when a thread state is deleted normally, but not when it
 * is destroyed after fork().
 * Pain: to prevent rare but fatal shutdown errors (issue 18808),
 * Thread.join() must wait for the join'ed thread's tstate to be unlinked
 * from the tstate chain. That happens at the end of a thread's life,
 * in pystate.c.
 * The obvious way doesn't quite work: create a lock which the tstate
 * unlinking code releases, and have Thread.join() wait to acquire that
 * lock. The problem is that we _are_ at the end of the thread's life:
 * if the thread holds the last reference to the lock, decref'ing the
 * lock will delete the lock, and that may trigger arbitrary Python code
 * if there's a weakref, with a callback, to the lock. But by this time
 * _PyRuntime.gilstate.tstate_current is already NULL, so only the simplest
 * of C code can be allowed to run (in particular it must not be possible to
 * release the GIL).
 * So instead of holding the lock directly, the tstate holds a weakref to
 * the lock: that's the value of on_delete_data below. Decref'ing a
 * weakref is harmless.
 * on_delete points to _threadmodule.c's static release_sentinel() function.
 * After the tstate is unlinked, release_sentinel is called with the
 * weakref-to-lock (on_delete_data) argument, and release_sentinel releases
 * the indirectly held lock.
 */
 void (*on_delete)(void *);
 void *on_delete_data;

 int coroutine_origin_tracking_depth;

 PyObject *async_gen_firstiter;
 PyObject *async_gen_finalizer;

 PyObject *context;
 uint64_t context_ver;

 /* Unique thread state id. */
 uint64_t id;

 /* XXX signal handlers should also be here */

};

/* Get the current interpreter state.

 Issue a fatal error if there no current Python thread state or no current
 interpreter. It cannot return NULL.

 The caller must hold the GIL.*/
PyAPI_FUNC(PyInterpreterState *) _PyInterpreterState_Get(void);

PyAPI_FUNC(int) _PyState_AddModule(PyObject*, struct PyModuleDef*);
PyAPI_FUNC(void) _PyState_ClearModules(void);
PyAPI_FUNC(PyThreadState *) _PyThreadState_Prealloc(PyInterpreterState *);

/* Similar to PyThreadState_Get(), but don't issue a fatal error
 * if it is NULL. */
PyAPI_FUNC(PyThreadState *) _PyThreadState_UncheckedGet(void);

/* PyGILState */

/* Helper/diagnostic function - return 1 if the current thread
 currently holds the GIL, 0 otherwise.

 The function returns 1 if _PyGILState_check_enabled is non-zero. */
PyAPI_FUNC(int) PyGILState_Check(void);

/* Get the single PyInterpreterState used by this process' GILState
 implementation.

 This function doesn't check for error. Return NULL before _PyGILState_Init()
 is called and after _PyGILState_Fini() is called.

 See also _PyInterpreterState_Get() and _PyInterpreterState_GET_UNSAFE(). */
PyAPI_FUNC(PyInterpreterState *) _PyGILState_GetInterpreterStateUnsafe(void);

/* The implementation of sys._current_frames() Returns a dict mapping
 thread id to that thread's current frame.
*/
PyAPI_FUNC(PyObject *) _PyThread_CurrentFrames(void);

/* Routines for advanced debuggers, requested by David Beazley.
 Don't use unless you know what you are doing! */
PyAPI_FUNC(PyInterpreterState *) PyInterpreterState_Main(void);
PyAPI_FUNC(PyInterpreterState *) PyInterpreterState_Head(void);
PyAPI_FUNC(PyInterpreterState *) PyInterpreterState_Next(PyInterpreterState *);
PyAPI_FUNC(PyThreadState *) PyInterpreterState_ThreadHead(PyInterpreterState *);
PyAPI_FUNC(PyThreadState *) PyThreadState_Next(PyThreadState *);

typedef struct _frame *(*PyThreadFrameGetter)(PyThreadState *self_);

/* cross-interpreter data */

struct _xid;

// _PyCrossInterpreterData is similar to Py_buffer as an effectively
// opaque struct that holds data outside the object machinery. This
// is necessary to pass safely between interpreters in the same process.
typedef struct _xid {
 // data is the cross-interpreter-safe derivation of a Python object
 // (see _PyObject_GetCrossInterpreterData). It will be NULL if the
 // new_object func (below) encodes the data.
 void *data;
 // obj is the Python object from which the data was derived. This
 // is non-NULL only if the data remains bound to the object in some
 // way, such that the object must be "released" (via a decref) when
 // the data is released. In that case the code that sets the field,
 // likely a registered "crossinterpdatafunc", is responsible for
 // ensuring it owns the reference (i.e. incref).
 PyObject *obj;
 // interp is the ID of the owning interpreter of the original
 // object. It corresponds to the active interpreter when
 // _PyObject_GetCrossInterpreterData() was called. This should only
 // be set by the cross-interpreter machinery.
 //
 // We use the ID rather than the PyInterpreterState to avoid issues
 // with deleted interpreters. Note that IDs are never re-used, so
 // each one will always correspond to a specific interpreter
 // (whether still alive or not).
 int64_t interp;
 // new_object is a function that returns a new object in the current
 // interpreter given the data. The resulting object (a new
 // reference) will be equivalent to the original object. This field
 // is required.
 PyObject *(*new_object)(struct _xid *);
 // free is called when the data is released. If it is NULL then
 // nothing will be done to free the data. For some types this is
 // okay (e.g. bytes) and for those types this field should be set
 // to NULL. However, for most the data was allocated just for
 // cross-interpreter use, so it must be freed when
 // _PyCrossInterpreterData_Release is called or the memory will
 // leak. In that case, at the very least this field should be set
 // to PyMem_RawFree (the default if not explicitly set to NULL).
 // The call will happen with the original interpreter activated.
 void (*free)(void *);
} _PyCrossInterpreterData;

PyAPI_FUNC(int) _PyObject_GetCrossInterpreterData(PyObject *, _PyCrossInterpreterData *);
PyAPI_FUNC(PyObject *) _PyCrossInterpreterData_NewObject(_PyCrossInterpreterData *);
PyAPI_FUNC(void) _PyCrossInterpreterData_Release(_PyCrossInterpreterData *);

PyAPI_FUNC(int) _PyObject_CheckCrossInterpreterData(PyObject *);

/* cross-interpreter data registry */

typedef int (*crossinterpdatafunc)(PyObject *, struct _xid *);

PyAPI_FUNC(int) _PyCrossInterpreterData_RegisterClass(PyTypeObject *, crossinterpdatafunc);
PyAPI_FUNC(crossinterpdatafunc) _PyCrossInterpreterData_Lookup(PyObject *);

#ifdef __cplusplus
}
#endif