mirror of
				https://github.com/python/cpython.git
				synced 2025-11-04 07:31:38 +00:00 
			
		
		
		
	
		
			
				
	
	
		
			964 lines
		
	
	
	
		
			23 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			964 lines
		
	
	
	
		
			23 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*
 | 
						|
 
 | 
						|
  Reference Cycle Garbage Collection
 | 
						|
  ==================================
 | 
						|
 | 
						|
  Neil Schemenauer <nas@arctrix.com>
 | 
						|
 | 
						|
  Based on a post on the python-dev list.  Ideas from Guido van Rossum,
 | 
						|
  Eric Tiedemann, and various others.
 | 
						|
 | 
						|
  http://www.arctrix.com/nas/python/gc/
 | 
						|
  http://www.python.org/pipermail/python-dev/2000-March/003869.html
 | 
						|
  http://www.python.org/pipermail/python-dev/2000-March/004010.html
 | 
						|
  http://www.python.org/pipermail/python-dev/2000-March/004022.html
 | 
						|
 | 
						|
  For a highlevel view of the collection process, read the collect
 | 
						|
  function.
 | 
						|
 | 
						|
*/
 | 
						|
 | 
						|
#include "Python.h"
 | 
						|
 | 
						|
#ifdef WITH_CYCLE_GC
 | 
						|
 | 
						|
/* Get an object's GC head */
 | 
						|
#define AS_GC(o) ((PyGC_Head *)(o)-1)
 | 
						|
 | 
						|
/* Get the object given the GC head */
 | 
						|
#define FROM_GC(g) ((PyObject *)(((PyGC_Head *)g)+1))
 | 
						|
 | 
						|
/* True if an object is tracked by the GC */
 | 
						|
#define IS_TRACKED(o) ((AS_GC(o))->gc.gc_next != NULL)
 | 
						|
 | 
						|
/*** Global GC state ***/
 | 
						|
 | 
						|
struct gc_generation {
 | 
						|
	PyGC_Head head;
 | 
						|
	int threshold; /* collection threshold */
 | 
						|
	int count; /* count of allocations or collections of younger
 | 
						|
		      generations */
 | 
						|
};
 | 
						|
 | 
						|
#define NUM_GENERATIONS 3
 | 
						|
#define GEN_HEAD(n) (&generations[n].head)
 | 
						|
 | 
						|
/* linked lists of container objects */
 | 
						|
static struct gc_generation generations[NUM_GENERATIONS] = {
 | 
						|
	/* PyGC_Head,				threshold,	count */
 | 
						|
	{{{GEN_HEAD(0), GEN_HEAD(0), 0}},	700,		0},
 | 
						|
	{{{GEN_HEAD(1), GEN_HEAD(1), 0}},	10,		0},
 | 
						|
	{{{GEN_HEAD(2), GEN_HEAD(2), 0}},	10,		0},
 | 
						|
};
 | 
						|
 | 
						|
PyGC_Head *_PyGC_generation0 = GEN_HEAD(0);
 | 
						|
 | 
						|
static int enabled = 1; /* automatic collection enabled? */
 | 
						|
 | 
						|
/* true if we are currently running the collector */
 | 
						|
static int collecting;
 | 
						|
 | 
						|
/* set for debugging information */
 | 
						|
#define DEBUG_STATS		(1<<0) /* print collection statistics */
 | 
						|
#define DEBUG_COLLECTABLE	(1<<1) /* print collectable objects */
 | 
						|
#define DEBUG_UNCOLLECTABLE	(1<<2) /* print uncollectable objects */
 | 
						|
#define DEBUG_INSTANCES		(1<<3) /* print instances */
 | 
						|
#define DEBUG_OBJECTS		(1<<4) /* print other objects */
 | 
						|
#define DEBUG_SAVEALL		(1<<5) /* save all garbage in gc.garbage */
 | 
						|
#define DEBUG_LEAK		DEBUG_COLLECTABLE | \
 | 
						|
				DEBUG_UNCOLLECTABLE | \
 | 
						|
				DEBUG_INSTANCES | \
 | 
						|
				DEBUG_OBJECTS | \
 | 
						|
				DEBUG_SAVEALL
 | 
						|
static int debug;
 | 
						|
 | 
						|
/* Special gc_refs value */
 | 
						|
#define GC_MOVED  -123
 | 
						|
 | 
						|
/* True if an object has been moved to the older generation */
 | 
						|
#define IS_MOVED(o) ((AS_GC(o))->gc.gc_refs == GC_MOVED)
 | 
						|
 | 
						|
/* list of uncollectable objects */
 | 
						|
static PyObject *garbage;
 | 
						|
 | 
						|
/* Python string to use if unhandled exception occurs */
 | 
						|
static PyObject *gc_str;
 | 
						|
 | 
						|
/*** list functions ***/
 | 
						|
 | 
						|
static void
 | 
						|
gc_list_init(PyGC_Head *list)
 | 
						|
{
 | 
						|
	list->gc.gc_prev = list;
 | 
						|
	list->gc.gc_next = list;
 | 
						|
}
 | 
						|
 | 
						|
static int
 | 
						|
gc_list_is_empty(PyGC_Head *list)
 | 
						|
{
 | 
						|
	return (list->gc.gc_next == list);
 | 
						|
}
 | 
						|
 | 
						|
static void
 | 
						|
gc_list_append(PyGC_Head *node, PyGC_Head *list)
 | 
						|
{
 | 
						|
	node->gc.gc_next = list;
 | 
						|
	node->gc.gc_prev = list->gc.gc_prev;
 | 
						|
	node->gc.gc_prev->gc.gc_next = node;
 | 
						|
	list->gc.gc_prev = node;
 | 
						|
}
 | 
						|
 | 
						|
static void
 | 
						|
gc_list_remove(PyGC_Head *node)
 | 
						|
{
 | 
						|
	node->gc.gc_prev->gc.gc_next = node->gc.gc_next;
 | 
						|
	node->gc.gc_next->gc.gc_prev = node->gc.gc_prev;
 | 
						|
	node->gc.gc_next = NULL; /* object is not currently tracked */
 | 
						|
}
 | 
						|
 | 
						|
static void 
 | 
						|
gc_list_move(PyGC_Head *from, PyGC_Head *to)
 | 
						|
{
 | 
						|
	if (gc_list_is_empty(from)) {
 | 
						|
		gc_list_init(to);
 | 
						|
	}
 | 
						|
	else {
 | 
						|
		to->gc.gc_next = from->gc.gc_next;
 | 
						|
		to->gc.gc_next->gc.gc_prev = to;
 | 
						|
		to->gc.gc_prev = from->gc.gc_prev;
 | 
						|
		to->gc.gc_prev->gc.gc_next = to;
 | 
						|
	}
 | 
						|
	gc_list_init(from);
 | 
						|
}
 | 
						|
 | 
						|
/* append a list onto another list, from becomes an empty list */
 | 
						|
static void
 | 
						|
gc_list_merge(PyGC_Head *from, PyGC_Head *to)
 | 
						|
{
 | 
						|
	PyGC_Head *tail;
 | 
						|
	if (!gc_list_is_empty(from)) {
 | 
						|
		tail = to->gc.gc_prev;
 | 
						|
		tail->gc.gc_next = from->gc.gc_next;
 | 
						|
		tail->gc.gc_next->gc.gc_prev = tail;
 | 
						|
		to->gc.gc_prev = from->gc.gc_prev;
 | 
						|
		to->gc.gc_prev->gc.gc_next = to;
 | 
						|
	}
 | 
						|
	gc_list_init(from);
 | 
						|
}
 | 
						|
 | 
						|
static long
 | 
						|
gc_list_size(PyGC_Head *list)
 | 
						|
{
 | 
						|
	PyGC_Head *gc;
 | 
						|
	long n = 0;
 | 
						|
	for (gc = list->gc.gc_next; gc != list; gc = gc->gc.gc_next) {
 | 
						|
		n++;
 | 
						|
	}
 | 
						|
	return n;
 | 
						|
}
 | 
						|
 | 
						|
/*** end of list stuff ***/
 | 
						|
 | 
						|
 | 
						|
 | 
						|
/* Set all gc_refs = ob_refcnt */
 | 
						|
static void
 | 
						|
update_refs(PyGC_Head *containers)
 | 
						|
{
 | 
						|
	PyGC_Head *gc = containers->gc.gc_next;
 | 
						|
	for (; gc != containers; gc=gc->gc.gc_next) {
 | 
						|
		gc->gc.gc_refs = FROM_GC(gc)->ob_refcnt;
 | 
						|
	}
 | 
						|
}
 | 
						|
 | 
						|
static int
 | 
						|
visit_decref(PyObject *op, void *data)
 | 
						|
{
 | 
						|
	if (op && PyObject_IS_GC(op)) {
 | 
						|
		if (IS_TRACKED(op))
 | 
						|
			AS_GC(op)->gc.gc_refs--;
 | 
						|
	}
 | 
						|
	return 0;
 | 
						|
}
 | 
						|
 | 
						|
/* Subtract internal references from gc_refs */
 | 
						|
static void
 | 
						|
subtract_refs(PyGC_Head *containers)
 | 
						|
{
 | 
						|
	traverseproc traverse;
 | 
						|
	PyGC_Head *gc = containers->gc.gc_next;
 | 
						|
	for (; gc != containers; gc=gc->gc.gc_next) {
 | 
						|
		traverse = FROM_GC(gc)->ob_type->tp_traverse;
 | 
						|
		(void) traverse(FROM_GC(gc),
 | 
						|
			       (visitproc)visit_decref,
 | 
						|
			       NULL);
 | 
						|
	}
 | 
						|
}
 | 
						|
 | 
						|
/* Append objects with gc_refs > 0 to roots list */
 | 
						|
static void
 | 
						|
move_roots(PyGC_Head *containers, PyGC_Head *roots)
 | 
						|
{
 | 
						|
	PyGC_Head *next;
 | 
						|
	PyGC_Head *gc = containers->gc.gc_next;
 | 
						|
	while (gc != containers) {
 | 
						|
		next = gc->gc.gc_next;
 | 
						|
		if (gc->gc.gc_refs > 0) {
 | 
						|
			gc_list_remove(gc);
 | 
						|
			gc_list_append(gc, roots);
 | 
						|
			gc->gc.gc_refs = GC_MOVED;
 | 
						|
		}
 | 
						|
		gc = next;
 | 
						|
	}
 | 
						|
}
 | 
						|
 | 
						|
static int
 | 
						|
visit_move(PyObject *op, PyGC_Head *tolist)
 | 
						|
{
 | 
						|
	if (PyObject_IS_GC(op)) {
 | 
						|
		if (IS_TRACKED(op) && !IS_MOVED(op)) {
 | 
						|
			PyGC_Head *gc = AS_GC(op);
 | 
						|
			gc_list_remove(gc);
 | 
						|
			gc_list_append(gc, tolist);
 | 
						|
			gc->gc.gc_refs = GC_MOVED;
 | 
						|
		}
 | 
						|
	}
 | 
						|
	return 0;
 | 
						|
}
 | 
						|
 | 
						|
/* Move objects referenced from reachable to reachable set. */
 | 
						|
static void
 | 
						|
move_root_reachable(PyGC_Head *reachable)
 | 
						|
{
 | 
						|
	traverseproc traverse;
 | 
						|
	PyGC_Head *gc = reachable->gc.gc_next;
 | 
						|
	for (; gc != reachable; gc=gc->gc.gc_next) {
 | 
						|
		/* careful, reachable list is growing here */
 | 
						|
		PyObject *op = FROM_GC(gc);
 | 
						|
		traverse = op->ob_type->tp_traverse;
 | 
						|
		(void) traverse(op,
 | 
						|
			       (visitproc)visit_move,
 | 
						|
			       (void *)reachable);
 | 
						|
	}
 | 
						|
}
 | 
						|
 | 
						|
/* return true of object has a finalization method */
 | 
						|
static int
 | 
						|
has_finalizer(PyObject *op)
 | 
						|
{
 | 
						|
	static PyObject *delstr = NULL;
 | 
						|
	if (delstr == NULL) {
 | 
						|
		delstr = PyString_InternFromString("__del__");
 | 
						|
		if (delstr == NULL)
 | 
						|
			Py_FatalError("PyGC: can't initialize __del__ string");
 | 
						|
	}
 | 
						|
	return (PyInstance_Check(op) ||
 | 
						|
	        PyType_HasFeature(op->ob_type, Py_TPFLAGS_HEAPTYPE))
 | 
						|
	       && PyObject_HasAttr(op, delstr);
 | 
						|
}
 | 
						|
 | 
						|
/* Move all objects with finalizers (instances with __del__) */
 | 
						|
static void
 | 
						|
move_finalizers(PyGC_Head *unreachable, PyGC_Head *finalizers)
 | 
						|
{
 | 
						|
	PyGC_Head *next;
 | 
						|
	PyGC_Head *gc = unreachable->gc.gc_next;
 | 
						|
	for (; gc != unreachable; gc=next) {
 | 
						|
		PyObject *op = FROM_GC(gc);
 | 
						|
		next = gc->gc.gc_next;
 | 
						|
		if (has_finalizer(op)) {
 | 
						|
			gc_list_remove(gc);
 | 
						|
			gc_list_append(gc, finalizers);
 | 
						|
		}
 | 
						|
	}
 | 
						|
}
 | 
						|
 | 
						|
/* Move objects referenced from roots to roots */
 | 
						|
static void
 | 
						|
move_finalizer_reachable(PyGC_Head *finalizers)
 | 
						|
{
 | 
						|
	traverseproc traverse;
 | 
						|
	PyGC_Head *gc = finalizers->gc.gc_next;
 | 
						|
	for (; gc != finalizers; gc=gc->gc.gc_next) {
 | 
						|
		/* careful, finalizers list is growing here */
 | 
						|
		traverse = FROM_GC(gc)->ob_type->tp_traverse;
 | 
						|
		(void) traverse(FROM_GC(gc), 
 | 
						|
			       (visitproc)visit_move,
 | 
						|
			       (void *)finalizers);
 | 
						|
	}
 | 
						|
}
 | 
						|
 | 
						|
static void
 | 
						|
debug_instance(char *msg, PyInstanceObject *inst)
 | 
						|
{
 | 
						|
	char *cname;
 | 
						|
	/* simple version of instance_repr */
 | 
						|
	PyObject *classname = inst->in_class->cl_name;
 | 
						|
	if (classname != NULL && PyString_Check(classname))
 | 
						|
		cname = PyString_AsString(classname);
 | 
						|
	else
 | 
						|
		cname = "?";
 | 
						|
	PySys_WriteStderr("gc: %.100s <%.100s instance at %p>\n",
 | 
						|
			  msg, cname, inst);
 | 
						|
}
 | 
						|
 | 
						|
static void
 | 
						|
debug_cycle(char *msg, PyObject *op)
 | 
						|
{
 | 
						|
	if ((debug & DEBUG_INSTANCES) && PyInstance_Check(op)) {
 | 
						|
		debug_instance(msg, (PyInstanceObject *)op);
 | 
						|
	}
 | 
						|
	else if (debug & DEBUG_OBJECTS) {
 | 
						|
		PySys_WriteStderr("gc: %.100s <%.100s %p>\n",
 | 
						|
				  msg, op->ob_type->tp_name, op);
 | 
						|
	}
 | 
						|
}
 | 
						|
 | 
						|
/* Handle uncollectable garbage (cycles with finalizers). */
 | 
						|
static void
 | 
						|
handle_finalizers(PyGC_Head *finalizers, PyGC_Head *old)
 | 
						|
{
 | 
						|
	PyGC_Head *gc;
 | 
						|
	if (garbage == NULL) {
 | 
						|
		garbage = PyList_New(0);
 | 
						|
	}
 | 
						|
	for (gc = finalizers->gc.gc_next; gc != finalizers;
 | 
						|
			gc = finalizers->gc.gc_next) {
 | 
						|
		PyObject *op = FROM_GC(gc);
 | 
						|
		if ((debug & DEBUG_SAVEALL) || has_finalizer(op)) {
 | 
						|
			/* If SAVEALL is not set then just append objects with
 | 
						|
			 * finalizers to the list of garbage.  All objects in
 | 
						|
			 * the finalizers list are reachable from those
 | 
						|
			 * objects. */
 | 
						|
			PyList_Append(garbage, op);
 | 
						|
		}
 | 
						|
		/* object is now reachable again */ 
 | 
						|
		gc_list_remove(gc);
 | 
						|
		gc_list_append(gc, old);
 | 
						|
	}
 | 
						|
}
 | 
						|
 | 
						|
/* Break reference cycles by clearing the containers involved.	This is
 | 
						|
 * tricky business as the lists can be changing and we don't know which
 | 
						|
 * objects may be freed.  It is possible I screwed something up here. */
 | 
						|
static void
 | 
						|
delete_garbage(PyGC_Head *unreachable, PyGC_Head *old)
 | 
						|
{
 | 
						|
	inquiry clear;
 | 
						|
 | 
						|
	while (!gc_list_is_empty(unreachable)) {
 | 
						|
		PyGC_Head *gc = unreachable->gc.gc_next;
 | 
						|
		PyObject *op = FROM_GC(gc);
 | 
						|
		if (debug & DEBUG_SAVEALL) {
 | 
						|
			PyList_Append(garbage, op);
 | 
						|
		}
 | 
						|
		else {
 | 
						|
			if ((clear = op->ob_type->tp_clear) != NULL) {
 | 
						|
				Py_INCREF(op);
 | 
						|
				clear((PyObject *)op);
 | 
						|
				Py_DECREF(op);
 | 
						|
			}
 | 
						|
		}
 | 
						|
		if (unreachable->gc.gc_next == gc) {
 | 
						|
			/* object is still alive, move it, it may die later */
 | 
						|
			gc_list_remove(gc);
 | 
						|
			gc_list_append(gc, old);
 | 
						|
		}
 | 
						|
	}
 | 
						|
}
 | 
						|
 | 
						|
/* This is the main function.  Read this to understand how the
 | 
						|
 * collection process works. */
 | 
						|
static long
 | 
						|
collect(int generation)
 | 
						|
{
 | 
						|
	int i;
 | 
						|
	long n = 0;
 | 
						|
	long m = 0;
 | 
						|
	PyGC_Head *young; /* the generation we are examining */
 | 
						|
	PyGC_Head *old; /* next older generation */
 | 
						|
	PyGC_Head reachable;
 | 
						|
	PyGC_Head unreachable;
 | 
						|
	PyGC_Head finalizers;
 | 
						|
	PyGC_Head *gc;
 | 
						|
 | 
						|
	if (debug & DEBUG_STATS) {
 | 
						|
		PySys_WriteStderr("gc: collecting generation %d...\n",
 | 
						|
				  generation);
 | 
						|
		PySys_WriteStderr("gc: objects in each generation:");
 | 
						|
		for (i = 0; i < NUM_GENERATIONS; i++) {
 | 
						|
			PySys_WriteStderr(" %ld", gc_list_size(GEN_HEAD(i)));
 | 
						|
		}
 | 
						|
		PySys_WriteStderr("\n");
 | 
						|
	}
 | 
						|
 | 
						|
	/* update collection and allocation counters */
 | 
						|
	if (generation+1 < NUM_GENERATIONS)
 | 
						|
		generations[generation+1].count += 1;
 | 
						|
	for (i = 0; i <= generation; i++)
 | 
						|
		generations[generation].count = 0;
 | 
						|
 | 
						|
	/* merge younger generations with one we are currently collecting */
 | 
						|
	for (i = 0; i < generation; i++) {
 | 
						|
		gc_list_merge(GEN_HEAD(i), GEN_HEAD(generation));
 | 
						|
	}
 | 
						|
 | 
						|
	/* handy references */
 | 
						|
	young = GEN_HEAD(generation);
 | 
						|
	if (generation < NUM_GENERATIONS-1) {
 | 
						|
		old = GEN_HEAD(generation+1);
 | 
						|
	} else {
 | 
						|
		old = GEN_HEAD(NUM_GENERATIONS-1);
 | 
						|
	}
 | 
						|
 | 
						|
	/* Using ob_refcnt and gc_refs, calculate which objects in the
 | 
						|
	 * container set are reachable from outside the set (ie. have a
 | 
						|
	 * refcount greater than 0 when all the references within the
 | 
						|
	 * set are taken into account */
 | 
						|
	update_refs(young);
 | 
						|
	subtract_refs(young);
 | 
						|
 | 
						|
	/* Move everything reachable from outside the set into the
 | 
						|
	 * reachable set (ie. gc_refs > 0).  Next, move everything
 | 
						|
	 * reachable from objects in the reachable set. */
 | 
						|
	gc_list_init(&reachable);
 | 
						|
	move_roots(young, &reachable);
 | 
						|
	move_root_reachable(&reachable);
 | 
						|
 | 
						|
	/* move unreachable objects to a temporary list, new objects can be
 | 
						|
	 * allocated after this point */
 | 
						|
	gc_list_init(&unreachable);
 | 
						|
	gc_list_move(young, &unreachable);
 | 
						|
 | 
						|
	/* move reachable objects to next generation */
 | 
						|
	gc_list_merge(&reachable, old);
 | 
						|
 | 
						|
	/* Move objects reachable from finalizers, we can't safely delete
 | 
						|
	 * them.  Python programmers should take care not to create such
 | 
						|
	 * things.  For Python finalizers means instance objects with
 | 
						|
	 * __del__ methods. */
 | 
						|
	gc_list_init(&finalizers);
 | 
						|
	move_finalizers(&unreachable, &finalizers);
 | 
						|
	move_finalizer_reachable(&finalizers);
 | 
						|
 | 
						|
	/* Collect statistics on collectable objects found and print
 | 
						|
	 * debugging information. */
 | 
						|
	for (gc = unreachable.gc.gc_next; gc != &unreachable;
 | 
						|
			gc = gc->gc.gc_next) {
 | 
						|
		m++;
 | 
						|
		if (debug & DEBUG_COLLECTABLE) {
 | 
						|
			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");
 | 
						|
	}
 | 
						|
	return n+m;
 | 
						|
}
 | 
						|
 | 
						|
static long
 | 
						|
collect_generations(void)
 | 
						|
{
 | 
						|
	int i;
 | 
						|
	long n = 0;
 | 
						|
 | 
						|
	/* Find the oldest generation (higest numbered) where the count
 | 
						|
	 * exceeds the threshold.  Objects in the that generation and
 | 
						|
	 * generations younger than it will be collected. */
 | 
						|
	for (i = NUM_GENERATIONS-1; i >= 0; i--) {
 | 
						|
		if (generations[i].count > generations[i].threshold) {
 | 
						|
			n = collect(i);
 | 
						|
			break;
 | 
						|
		}
 | 
						|
	}
 | 
						|
	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;
 | 
						|
		n = collect(NUM_GENERATIONS - 1);
 | 
						|
		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)
 | 
						|
{
 | 
						|
	int i;
 | 
						|
	if (!PyArg_ParseTuple(args, "i|ii:set_threshold",
 | 
						|
			      &generations[0].threshold,
 | 
						|
			      &generations[1].threshold,
 | 
						|
			      &generations[2].threshold))
 | 
						|
		return NULL;
 | 
						|
	for (i = 2; i < NUM_GENERATIONS; i++) {
 | 
						|
 		/* generations higher than 2 get the same threshold */
 | 
						|
		generations[i].threshold = generations[2].threshold;
 | 
						|
	}
 | 
						|
 | 
						|
	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)",
 | 
						|
			     generations[0].threshold,
 | 
						|
			     generations[1].threshold,
 | 
						|
			     generations[2].threshold);
 | 
						|
}
 | 
						|
 | 
						|
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)
 | 
						|
{
 | 
						|
	int i;
 | 
						|
	PyObject *result = PyList_New(0);
 | 
						|
	for (i = 0; i < NUM_GENERATIONS; i++) {
 | 
						|
		if (!(gc_referrers_for(args, GEN_HEAD(i), 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)
 | 
						|
{
 | 
						|
	int i;
 | 
						|
	PyObject* result;
 | 
						|
 | 
						|
	if (!PyArg_ParseTuple(args, ":get_objects")) /* check no args */
 | 
						|
		return NULL;
 | 
						|
	result = PyList_New(0);
 | 
						|
	if (result == NULL) {
 | 
						|
		return NULL;
 | 
						|
	}
 | 
						|
	for (i = 0; i < NUM_GENERATIONS; i++) {
 | 
						|
		if (append_objects(result, GEN_HEAD(i))) {
 | 
						|
			Py_DECREF(result);
 | 
						|
			return NULL;
 | 
						|
		}
 | 
						|
	}
 | 
						|
	return result;
 | 
						|
}
 | 
						|
 | 
						|
 | 
						|
static char gc__doc__ [] =
 | 
						|
"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"
 | 
						|
;
 | 
						|
 | 
						|
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 */
 | 
						|
};
 | 
						|
 | 
						|
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 */
 | 
						|
 | 
						|
#undef PyObject_GC_Track
 | 
						|
#undef PyObject_GC_UnTrack
 | 
						|
#undef PyObject_GC_Del
 | 
						|
#undef _PyObject_GC_Malloc
 | 
						|
 | 
						|
void
 | 
						|
PyObject_GC_Track(void *op)
 | 
						|
{
 | 
						|
	_PyObject_GC_TRACK(op);
 | 
						|
}
 | 
						|
 | 
						|
/* for binary compatibility with 2.2 */
 | 
						|
void
 | 
						|
_PyObject_GC_Track(PyObject *op)
 | 
						|
{
 | 
						|
    PyObject_GC_Track(op);
 | 
						|
}
 | 
						|
 | 
						|
void
 | 
						|
PyObject_GC_UnTrack(void *op)
 | 
						|
{
 | 
						|
#ifdef WITH_CYCLE_GC
 | 
						|
	if (IS_TRACKED(op))
 | 
						|
		_PyObject_GC_UNTRACK(op);
 | 
						|
#endif
 | 
						|
}
 | 
						|
 | 
						|
/* for binary compatibility with 2.2 */
 | 
						|
void
 | 
						|
_PyObject_GC_UnTrack(PyObject *op)
 | 
						|
{
 | 
						|
    PyObject_GC_UnTrack(op);
 | 
						|
}
 | 
						|
 | 
						|
PyObject *
 | 
						|
_PyObject_GC_Malloc(size_t basicsize)
 | 
						|
{
 | 
						|
	PyObject *op;
 | 
						|
#ifdef WITH_CYCLE_GC
 | 
						|
	PyGC_Head *g = PyObject_MALLOC(sizeof(PyGC_Head) + basicsize);
 | 
						|
	if (g == NULL)
 | 
						|
		return (PyObject *)PyErr_NoMemory();
 | 
						|
	g->gc.gc_next = NULL;
 | 
						|
	generations[0].count++; /* number of allocated GC objects */
 | 
						|
 	if (generations[0].count > generations[0].threshold &&
 | 
						|
 	    enabled &&
 | 
						|
 	    generations[0].threshold &&
 | 
						|
 	    !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;
 | 
						|
}
 | 
						|
 | 
						|
PyObject *
 | 
						|
_PyObject_GC_New(PyTypeObject *tp)
 | 
						|
{
 | 
						|
	PyObject *op = _PyObject_GC_Malloc(_PyObject_SIZE(tp));
 | 
						|
	if (op != NULL)
 | 
						|
		op = PyObject_INIT(op, tp);
 | 
						|
	return op;
 | 
						|
}
 | 
						|
 | 
						|
PyVarObject *
 | 
						|
_PyObject_GC_NewVar(PyTypeObject *tp, int nitems)
 | 
						|
{
 | 
						|
	const size_t size = _PyObject_VAR_SIZE(tp, nitems);
 | 
						|
	PyVarObject *op = (PyVarObject *) _PyObject_GC_Malloc(size);
 | 
						|
	if (op != NULL)
 | 
						|
		op = PyObject_INIT_VAR(op, tp, nitems);
 | 
						|
	return op;
 | 
						|
}
 | 
						|
 | 
						|
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;
 | 
						|
}
 | 
						|
 | 
						|
void
 | 
						|
PyObject_GC_Del(void *op)
 | 
						|
{
 | 
						|
#ifdef WITH_CYCLE_GC
 | 
						|
	PyGC_Head *g = AS_GC(op);
 | 
						|
	if (IS_TRACKED(op))
 | 
						|
		gc_list_remove(g);
 | 
						|
	if (generations[0].count > 0) {
 | 
						|
		generations[0].count--;
 | 
						|
	}
 | 
						|
	PyObject_FREE(g);
 | 
						|
#else
 | 
						|
	PyObject_FREE(op);
 | 
						|
#endif
 | 
						|
}
 | 
						|
 | 
						|
/* for binary compatibility with 2.2 */
 | 
						|
#undef _PyObject_GC_Del
 | 
						|
void
 | 
						|
_PyObject_GC_Del(PyObject *op)
 | 
						|
{
 | 
						|
    PyObject_GC_Del(op);
 | 
						|
}
 |