gcmodule.c

python s60 1.4.5版本的源代码

			debug_cycle("collectable", FROM_GC(gc));
		}
	}
	/* call tp_clear on objects in the collectable set.  This will cause
	 * the reference cycles to be broken. It may also cause some objects in
	 * finalizers to be freed */
	delete_garbage(&unreachable, old);

	/* Collect statistics on uncollectable objects found and print
	 * debugging information. */
	for (gc = finalizers.gc.gc_next; gc != &finalizers;
			gc = gc->gc.gc_next) {
		n++;
		if (debug & DEBUG_UNCOLLECTABLE) {
			debug_cycle("uncollectable", FROM_GC(gc));
		}
	}
	if (debug & DEBUG_STATS) {
		if (m == 0 && n == 0) {
			PySys_WriteStderr("gc: done.\n");
		}
		else {
			PySys_WriteStderr(
			    "gc: done, %ld unreachable, %ld uncollectable.\n",
			    n+m, n);
		}
	}

	/* Append instances in the uncollectable set to a Python
	 * reachable list of garbage.  The programmer has to deal with
	 * this if they insist on creating this type of structure. */
	handle_finalizers(&finalizers, old);

	if (PyErr_Occurred()) {
		if (gc_str == NULL) {
		    gc_str = PyString_FromString("garbage collection");
		}
		PyErr_WriteUnraisable(gc_str);
		Py_FatalError("unexpected exception during garbage collection");
	}
	allocated = 0;
	return n+m;
}

static long
collect_generations(void)
{
#ifndef SYMBIAN
	static long collections0 = 0;
	static long collections1 = 0;
#else
#define collections0 (GC_GLOBALS->collect_generations_collections0)
#define collections1 (GC_GLOBALS->collect_generations_collections1)
#endif
	long n = 0;


	if (collections1 > threshold2) {
		generation = 2;
		gc_list_merge(&_PyGC_generation0, &generation2);
		gc_list_merge(&generation1, &generation2);
		if (generation2.gc.gc_next != &generation2) {
			n = collect(&generation2, &generation2);
		}
		collections1 = 0;
	}
	else if (collections0 > threshold1) {
		generation = 1;
		collections1++;
		gc_list_merge(&_PyGC_generation0, &generation1);
		if (generation1.gc.gc_next != &generation1) {
			n = collect(&generation1, &generation2);
		}
		collections0 = 0;
	}
	else {
		generation = 0;
		collections0++;
		if (_PyGC_generation0.gc.gc_next != &_PyGC_generation0) {
			n = collect(&_PyGC_generation0, &generation1);
		}
	}
	return n;
}

static char gc_enable__doc__[] =
"enable() -> None\n"
"\n"
"Enable automatic garbage collection.\n"
;

static PyObject *
gc_enable(PyObject *self, PyObject *args)
{

	if (!PyArg_ParseTuple(args, ":enable"))	/* check no args */
		return NULL;

	enabled = 1;

	Py_INCREF(Py_None);
	return Py_None;
}

static char gc_disable__doc__[] =
"disable() -> None\n"
"\n"
"Disable automatic garbage collection.\n"
;

static PyObject *
gc_disable(PyObject *self, PyObject *args)
{

	if (!PyArg_ParseTuple(args, ":disable"))	/* check no args */
		return NULL;

	enabled = 0;

	Py_INCREF(Py_None);
	return Py_None;
}

static char gc_isenabled__doc__[] =
"isenabled() -> status\n"
"\n"
"Returns true if automatic garbage collection is enabled.\n"
;

static PyObject *
gc_isenabled(PyObject *self, PyObject *args)
{

	if (!PyArg_ParseTuple(args, ":isenabled"))	/* check no args */
		return NULL;

	return Py_BuildValue("i", enabled);
}

static char gc_collect__doc__[] =
"collect() -> n\n"
"\n"
"Run a full collection.  The number of unreachable objects is returned.\n"
;

static PyObject *
gc_collect(PyObject *self, PyObject *args)
{
	long n;

	if (!PyArg_ParseTuple(args, ":collect"))	/* check no args */
		return NULL;

	if (collecting) {
		n = 0; /* already collecting, don't do anything */
	}
	else {
		collecting = 1;
		generation = 2;
		gc_list_merge(&_PyGC_generation0, &generation2);
		gc_list_merge(&generation1, &generation2);
		n = collect(&generation2, &generation2);
		collecting = 0;
	}

	return Py_BuildValue("l", n);
}

static char gc_set_debug__doc__[] =
"set_debug(flags) -> None\n"
"\n"
"Set the garbage collection debugging flags. Debugging information is\n"
"written to sys.stderr.\n"
"\n"
"flags is an integer and can have the following bits turned on:\n"
"\n"
"  DEBUG_STATS - Print statistics during collection.\n"
"  DEBUG_COLLECTABLE - Print collectable objects found.\n"
"  DEBUG_UNCOLLECTABLE - Print unreachable but uncollectable objects found.\n"
"  DEBUG_INSTANCES - Print instance objects.\n"
"  DEBUG_OBJECTS - Print objects other than instances.\n"
"  DEBUG_SAVEALL - Save objects to gc.garbage rather than freeing them.\n"
"  DEBUG_LEAK - Debug leaking programs (everything but STATS).\n"
;

static PyObject *
gc_set_debug(PyObject *self, PyObject *args)
{
	if (!PyArg_ParseTuple(args, "i:set_debug", &debug))
		return NULL;

	Py_INCREF(Py_None);
	return Py_None;
}

static char gc_get_debug__doc__[] =
"get_debug() -> flags\n"
"\n"
"Get the garbage collection debugging flags.\n"
;

static PyObject *
gc_get_debug(PyObject *self, PyObject *args)
{
	if (!PyArg_ParseTuple(args, ":get_debug"))	/* no args */
		return NULL;

	return Py_BuildValue("i", debug);
}

static char gc_set_thresh__doc__[] =
"set_threshold(threshold0, [threshold1, threshold2]) -> None\n"
"\n"
"Sets the collection thresholds.  Setting threshold0 to zero disables\n"
"collection.\n"
;

static PyObject *
gc_set_thresh(PyObject *self, PyObject *args)
{
	if (!PyArg_ParseTuple(args, "i|ii:set_threshold", &threshold0,
				&threshold1, &threshold2))
		return NULL;

	Py_INCREF(Py_None);
	return Py_None;
}

static char gc_get_thresh__doc__[] =
"get_threshold() -> (threshold0, threshold1, threshold2)\n"
"\n"
"Return the current collection thresholds\n"
;

static PyObject *
gc_get_thresh(PyObject *self, PyObject *args)
{
	if (!PyArg_ParseTuple(args, ":get_threshold"))	/* no args */
		return NULL;

	return Py_BuildValue("(iii)", threshold0, threshold1, threshold2);
}

static int
referrersvisit(PyObject* obj, PyObject *objs)
{
	int i;
	for (i = 0; i < PyTuple_GET_SIZE(objs); i++)
		if (PyTuple_GET_ITEM(objs, i) == obj)
			return 1;
	return 0;
}

static int
gc_referrers_for(PyObject *objs, PyGC_Head *list, PyObject *resultlist)
{
	PyGC_Head *gc;
	PyObject *obj;
	traverseproc traverse;
	for (gc = list->gc.gc_next; gc != list; gc = gc->gc.gc_next) {
		obj = FROM_GC(gc);
		traverse = obj->ob_type->tp_traverse;
		if (obj == objs || obj == resultlist)
			continue;
		if (traverse(obj, (visitproc)referrersvisit, objs)) {
			if (PyList_Append(resultlist, obj) < 0)
				return 0; /* error */
		}
	}
	return 1; /* no error */
}

static char gc_get_referrers__doc__[]=
"get_referrers(*objs) -> list\n\
Return the list of objects that directly refer to any of objs.";

static PyObject *
gc_get_referrers(PyObject *self, PyObject *args)
{
	PyObject *result = PyList_New(0);
	if (!(gc_referrers_for(args, &_PyGC_generation0, result) &&
	      gc_referrers_for(args, &generation1, result) &&
	      gc_referrers_for(args, &generation2, result))) {
		Py_DECREF(result);
		return NULL;
	}
	return result;
}

static char gc_get_objects__doc__[] =
"get_objects() -> [...]\n"
"\n"
"Return a list of objects tracked by the collector (excluding the list\n"
"returned).\n"
;

/* appending objects in a GC list to a Python list */
static int
append_objects(PyObject *py_list, PyGC_Head *gc_list)
{
	PyGC_Head *gc;
	for (gc = gc_list->gc.gc_next; gc != gc_list; gc = gc->gc.gc_next) {
		PyObject *op = FROM_GC(gc);
		if (op != py_list) {
			if (PyList_Append(py_list, op)) {
				return -1; /* exception */
			}
		}
	}
	return 0;
}

static PyObject *
gc_get_objects(PyObject *self, PyObject *args)
{
	PyObject* result;

	if (!PyArg_ParseTuple(args, ":get_objects")) /* check no args */
		return NULL;
	result = PyList_New(0);
	if (result == NULL) {
		return NULL;
	}
	if (append_objects(result, &_PyGC_generation0) ||
	    append_objects(result, &generation1) ||
	    append_objects(result, &generation2)) {
		Py_DECREF(result);
		return NULL;
	}
	return result;
}


static char gc__doc__ [] =
#ifndef SYMBIAN
"This module provides access to the garbage collector for reference cycles.\n"
"\n"
"enable() -- Enable automatic garbage collection.\n"
"disable() -- Disable automatic garbage collection.\n"
"isenabled() -- Returns true if automatic collection is enabled.\n"
"collect() -- Do a full collection right now.\n"
"set_debug() -- Set debugging flags.\n"
"get_debug() -- Get debugging flags.\n"
"set_threshold() -- Set the collection thresholds.\n"
"get_threshold() -- Return the current the collection thresholds.\n"
"get_objects() -- Return a list of all objects tracked by the collector.\n"
"get_referrers() -- Return the list of objects that refer to an object.\n"
;
#else
"";
#endif

#ifndef SYMBIAN
static PyMethodDef GcMethods[] = {
	{"enable",	   gc_enable,	  METH_VARARGS, gc_enable__doc__},
	{"disable",	   gc_disable,	  METH_VARARGS, gc_disable__doc__},
	{"isenabled",	   gc_isenabled,  METH_VARARGS, gc_isenabled__doc__},
	{"set_debug",	   gc_set_debug,  METH_VARARGS, gc_set_debug__doc__},
	{"get_debug",	   gc_get_debug,  METH_VARARGS, gc_get_debug__doc__},
	{"set_threshold",  gc_set_thresh, METH_VARARGS, gc_set_thresh__doc__},
	{"get_threshold",  gc_get_thresh, METH_VARARGS, gc_get_thresh__doc__},
	{"collect",	   gc_collect,	  METH_VARARGS, gc_collect__doc__},
	{"get_objects",    gc_get_objects,METH_VARARGS, gc_get_objects__doc__},
	{"get_referrers",  gc_get_referrers, METH_VARARGS,
		gc_get_referrers__doc__},
	{NULL,	NULL}		/* Sentinel */
};
#else
static const PyMethodDef GcMethods[] = {
	{"enable",	   gc_enable,	  METH_VARARGS, NULL},
	{"disable",	   gc_disable,	  METH_VARARGS, NULL},
	{"isenabled",	   gc_isenabled,  METH_VARARGS, NULL}, 
	{"set_debug",	   gc_set_debug,  METH_VARARGS, NULL}, 
	{"get_debug",	   gc_get_debug,  METH_VARARGS, NULL}, 
	{"set_threshold",  gc_set_thresh, METH_VARARGS, NULL}, 
	{"get_threshold",  gc_get_thresh, METH_VARARGS, NULL}, 
	{"collect",	   gc_collect,	  METH_VARARGS, NULL}, 
	{"get_objects",    gc_get_objects,METH_VARARGS, NULL}, 
	{"get_referrers",  gc_get_referrers, METH_VARARGS, NULL},
	{NULL,	NULL}		/* Sentinel */
};
#endif

void
initgc(void)
{
	PyObject *m;
	PyObject *d;

	m = Py_InitModule4("gc",
			      GcMethods,
			      gc__doc__,
			      NULL,
			      PYTHON_API_VERSION);
	d = PyModule_GetDict(m);
	if (garbage == NULL) {
		garbage = PyList_New(0);
	}
	PyDict_SetItemString(d, "garbage", garbage);
	PyDict_SetItemString(d, "DEBUG_STATS",
			PyInt_FromLong(DEBUG_STATS));
	PyDict_SetItemString(d, "DEBUG_COLLECTABLE",
			PyInt_FromLong(DEBUG_COLLECTABLE));
	PyDict_SetItemString(d, "DEBUG_UNCOLLECTABLE",
			PyInt_FromLong(DEBUG_UNCOLLECTABLE));
	PyDict_SetItemString(d, "DEBUG_INSTANCES",
			PyInt_FromLong(DEBUG_INSTANCES));
	PyDict_SetItemString(d, "DEBUG_OBJECTS",
			PyInt_FromLong(DEBUG_OBJECTS));
	PyDict_SetItemString(d, "DEBUG_SAVEALL",
			PyInt_FromLong(DEBUG_SAVEALL));
	PyDict_SetItemString(d, "DEBUG_LEAK",
			PyInt_FromLong(DEBUG_LEAK));
}

/* for debugging */
void _PyGC_Dump(PyGC_Head *g)
{
	_PyObject_Dump(FROM_GC(g));
}

#endif /* WITH_CYCLE_GC */

/* extension modules might be compiled with GC support so these
   functions must always be available */

DL_EXPORT(void)
_PyObject_GC_Track(PyObject *op)
{
	_PyObject_GC_TRACK(op);
}

DL_EXPORT(void)
_PyObject_GC_UnTrack(PyObject *op)
{
#ifdef WITH_CYCLE_GC
	PyGC_Head *gc = AS_GC(op);
	if (gc->gc.gc_next != NULL)
		_PyObject_GC_UNTRACK(op);
#endif
}

DL_EXPORT(PyObject *)
_PyObject_GC_Malloc(PyTypeObject *tp, int nitems)
{
	PyObject *op;
	const size_t basicsize = _PyObject_VAR_SIZE(tp, nitems);
#ifdef WITH_CYCLE_GC
	const size_t nbytes = sizeof(PyGC_Head) + basicsize;
	PyGC_Head *g = PyObject_MALLOC(nbytes);
	if (g == NULL)
		return (PyObject *)PyErr_NoMemory();
	g->gc.gc_next = NULL;
#ifdef SYMBIAN
	if (GC_GLOBALS == NULL)
	  init_gc_globals();
#endif
	allocated++;
 	if (allocated > threshold0 &&
 	    enabled &&
 	    threshold0 &&
 	    !collecting &&
 	    !PyErr_Occurred()) {
		collecting = 1;
 		collect_generations();
		collecting = 0;
	}
	op = FROM_GC(g);
#else
	op = PyObject_MALLOC(basicsize);
	if (op == NULL)
		return (PyObject *)PyErr_NoMemory();

#endif
	return op;
}

DL_EXPORT(PyObject *)
_PyObject_GC_New(PyTypeObject *tp)
{
	PyObject *op = _PyObject_GC_Malloc(tp, 0);
	if (op != NULL)
		op = PyObject_INIT(op, tp);
	return op;
}

DL_EXPORT(PyVarObject *)
_PyObject_GC_NewVar(PyTypeObject *tp, int nitems)
{
	PyVarObject *op = (PyVarObject *) _PyObject_GC_Malloc(tp, nitems);
	if (op != NULL)
		op = PyObject_INIT_VAR(op, tp, nitems);
	return op;
}

DL_EXPORT(PyVarObject *)
_PyObject_GC_Resize(PyVarObject *op, int nitems)
{
	const size_t basicsize = _PyObject_VAR_SIZE(op->ob_type, nitems);
#ifdef WITH_CYCLE_GC
	PyGC_Head *g = AS_GC(op);
	g = PyObject_REALLOC(g,  sizeof(PyGC_Head) + basicsize);
	if (g == NULL)
		return (PyVarObject *)PyErr_NoMemory();
	op = (PyVarObject *) FROM_GC(g);
#else
	op = PyObject_REALLOC(op, basicsize);
	if (op == NULL)
		return (PyVarObject *)PyErr_NoMemory();
#endif
	op->ob_size = nitems;
	return op;
}

DL_EXPORT(void)
_PyObject_GC_Del(PyObject *op)
{
#ifdef WITH_CYCLE_GC
	PyGC_Head *g = AS_GC(op);
	if (g->gc.gc_next != NULL)
		gc_list_remove(g);
	if (allocated > 0) {
		allocated--;
	}
	PyObject_FREE(g);
#else
	PyObject_FREE(op);
#endif
}