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/* Thread and interpreter state structures and their interfaces */
#include "Python.h"
#define ZAP(x) { \
PyObject *tmp = (PyObject *)(x); \
(x) = NULL; \
Py_XDECREF(tmp); \
}
#ifdef WITH_THREAD
#include "pythread.h"
static PyThread_type_lock head_mutex = NULL; /* Protects interp->tstate_head */
#define HEAD_INIT() (void)(head_mutex || (head_mutex = PyThread_allocate_lock()))
#define HEAD_LOCK() PyThread_acquire_lock(head_mutex, WAIT_LOCK)
#define HEAD_UNLOCK() PyThread_release_lock(head_mutex)
#else
#define HEAD_INIT() /* Nothing */
#define HEAD_LOCK() /* Nothing */
#define HEAD_UNLOCK() /* Nothing */
#endif
static PyInterpreterState *interp_head = NULL;
PyThreadState *_PyThreadState_Current = NULL;
PyInterpreterState *
PyInterpreterState_New(void)
{
PyInterpreterState *interp = PyMem_NEW(PyInterpreterState, 1);
if (interp != NULL) {
HEAD_INIT();
interp->modules = NULL;
interp->sysdict = NULL;
interp->builtins = NULL;
interp->checkinterval = 10;
interp->tstate_head = NULL;
HEAD_LOCK();
interp->next = interp_head;
interp_head = interp;
HEAD_UNLOCK();
}
return interp;
}
void
PyInterpreterState_Clear(PyInterpreterState *interp)
{
PyThreadState *p;
HEAD_LOCK();
for (p = interp->tstate_head; p != NULL; p = p->next)
PyThreadState_Clear(p);
HEAD_UNLOCK();
ZAP(interp->modules);
ZAP(interp->sysdict);
ZAP(interp->builtins);
}
static void
zapthreads(PyInterpreterState *interp)
{
PyThreadState *p;
/* No need to lock the mutex here because this should only happen
when the threads are all really dead (XXX famous last words). */
while ((p = interp->tstate_head) != NULL) {
PyThreadState_Delete(p);
}
}
void
PyInterpreterState_Delete(PyInterpreterState *interp)
{
PyInterpreterState **p;
zapthreads(interp);
HEAD_LOCK();
for (p = &interp_head; ; p = &(*p)->next) {
if (*p == NULL)
Py_FatalError(
"PyInterpreterState_Delete: invalid interp");
if (*p == interp)
break;
}
if (interp->tstate_head != NULL)
Py_FatalError("PyInterpreterState_Delete: remaining threads");
*p = interp->next;
HEAD_UNLOCK();
PyMem_DEL(interp);
}
PyThreadState *
PyThreadState_New(PyInterpreterState *interp)
{
PyThreadState *tstate = PyMem_NEW(PyThreadState, 1);
if (tstate != NULL) {
tstate->interp = interp;
tstate->frame = NULL;
tstate->recursion_depth = 0;
tstate->ticker = 0;
tstate->tracing = 0;
tstate->dict = NULL;
tstate->curexc_type = NULL;
tstate->curexc_value = NULL;
tstate->curexc_traceback = NULL;
tstate->exc_type = NULL;
tstate->exc_value = NULL;
tstate->exc_traceback = NULL;
tstate->sys_profilefunc = NULL;
tstate->sys_tracefunc = NULL;
HEAD_LOCK();
tstate->next = interp->tstate_head;
interp->tstate_head = tstate;
HEAD_UNLOCK();
}
return tstate;
}
void
PyThreadState_Clear(PyThreadState *tstate)
{
if (Py_VerboseFlag && tstate->frame != NULL)
fprintf(stderr,
"PyThreadState_Clear: warning: thread still has a frame\n");
ZAP(tstate->frame);
ZAP(tstate->dict);
ZAP(tstate->curexc_type);
ZAP(tstate->curexc_value);
ZAP(tstate->curexc_traceback);
ZAP(tstate->exc_type);
ZAP(tstate->exc_value);
ZAP(tstate->exc_traceback);
ZAP(tstate->sys_profilefunc);
ZAP(tstate->sys_tracefunc);
}
/* Common code for PyThreadState_Delete() and PyThreadState_DeleteCurrent() */
static void
tstate_delete_common(PyThreadState *tstate)
{
PyInterpreterState *interp;
PyThreadState **p;
if (tstate == NULL)
Py_FatalError("PyThreadState_Delete: NULL tstate");
interp = tstate->interp;
if (interp == NULL)
Py_FatalError("PyThreadState_Delete: NULL interp");
HEAD_LOCK();
for (p = &interp->tstate_head; ; p = &(*p)->next) {
if (*p == NULL)
Py_FatalError(
"PyThreadState_Delete: invalid tstate");
if (*p == tstate)
break;
}
*p = tstate->next;
HEAD_UNLOCK();
PyMem_DEL(tstate);
}
void
PyThreadState_Delete(PyThreadState *tstate)
{
if (tstate == _PyThreadState_Current)
Py_FatalError("PyThreadState_Delete: tstate is still current");
tstate_delete_common(tstate);
}
#ifdef WITH_THREAD
void
PyThreadState_DeleteCurrent()
{
PyThreadState *tstate = _PyThreadState_Current;
if (tstate == NULL)
Py_FatalError(
"PyThreadState_DeleteCurrent: no current tstate");
_PyThreadState_Current = NULL;
tstate_delete_common(tstate);
PyEval_ReleaseLock();
}
#endif /* WITH_THREAD */
PyThreadState *
PyThreadState_Get(void)
{
if (_PyThreadState_Current == NULL)
Py_FatalError("PyThreadState_Get: no current thread");
return _PyThreadState_Current;
}
PyThreadState *
PyThreadState_Swap(PyThreadState *new)
{
PyThreadState *old = _PyThreadState_Current;
_PyThreadState_Current = new;
return old;
}
/* An extension mechanism to store arbitrary additional per-thread state.
PyThreadState_GetDict() returns a dictionary that can be used to hold such
state; the caller should pick a unique key and store its state there. If
PyThreadState_GetDict() returns NULL, an exception has been raised (most
likely MemoryError) and the caller should pass on the exception. */
PyObject *
PyThreadState_GetDict(void)
{
if (_PyThreadState_Current == NULL)
Py_FatalError("PyThreadState_GetDict: no current thread");
if (_PyThreadState_Current->dict == NULL)
_PyThreadState_Current->dict = PyDict_New();
return _PyThreadState_Current->dict;
}
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