Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 1 | /* |
Tim Peters | 8839617 | 2002-06-30 17:56:40 +0000 | [diff] [blame] | 2 | |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 3 | Reference Cycle Garbage Collection |
| 4 | ================================== |
| 5 | |
Neil Schemenauer | b2c2c9e | 2000-10-04 16:34:09 +0000 | [diff] [blame] | 6 | Neil Schemenauer <nas@arctrix.com> |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 7 | |
| 8 | Based on a post on the python-dev list. Ideas from Guido van Rossum, |
| 9 | Eric Tiedemann, and various others. |
| 10 | |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 11 | http://www.arctrix.com/nas/python/gc/ |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 12 | http://www.python.org/pipermail/python-dev/2000-March/003869.html |
| 13 | http://www.python.org/pipermail/python-dev/2000-March/004010.html |
| 14 | http://www.python.org/pipermail/python-dev/2000-March/004022.html |
| 15 | |
| 16 | For a highlevel view of the collection process, read the collect |
| 17 | function. |
| 18 | |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 19 | */ |
| 20 | |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 21 | #include "Python.h" |
| 22 | |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 23 | /* Get an object's GC head */ |
| 24 | #define AS_GC(o) ((PyGC_Head *)(o)-1) |
| 25 | |
| 26 | /* Get the object given the GC head */ |
| 27 | #define FROM_GC(g) ((PyObject *)(((PyGC_Head *)g)+1)) |
| 28 | |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 29 | /*** Global GC state ***/ |
| 30 | |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 31 | struct gc_generation { |
| 32 | PyGC_Head head; |
| 33 | int threshold; /* collection threshold */ |
| 34 | int count; /* count of allocations or collections of younger |
| 35 | generations */ |
| 36 | }; |
| 37 | |
| 38 | #define NUM_GENERATIONS 3 |
| 39 | #define GEN_HEAD(n) (&generations[n].head) |
| 40 | |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 41 | /* linked lists of container objects */ |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 42 | static struct gc_generation generations[NUM_GENERATIONS] = { |
| 43 | /* PyGC_Head, threshold, count */ |
| 44 | {{{GEN_HEAD(0), GEN_HEAD(0), 0}}, 700, 0}, |
| 45 | {{{GEN_HEAD(1), GEN_HEAD(1), 0}}, 10, 0}, |
| 46 | {{{GEN_HEAD(2), GEN_HEAD(2), 0}}, 10, 0}, |
| 47 | }; |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 48 | |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 49 | PyGC_Head *_PyGC_generation0 = GEN_HEAD(0); |
| 50 | |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 51 | static int enabled = 1; /* automatic collection enabled? */ |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 52 | |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 53 | /* true if we are currently running the collector */ |
Tim Peters | bf384c2 | 2003-04-06 00:11:39 +0000 | [diff] [blame] | 54 | static int collecting = 0; |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 55 | |
Tim Peters | 6fc13d9 | 2002-07-02 18:12:35 +0000 | [diff] [blame] | 56 | /* list of uncollectable objects */ |
Tim Peters | bf384c2 | 2003-04-06 00:11:39 +0000 | [diff] [blame] | 57 | static PyObject *garbage = NULL; |
Tim Peters | 6fc13d9 | 2002-07-02 18:12:35 +0000 | [diff] [blame] | 58 | |
| 59 | /* Python string to use if unhandled exception occurs */ |
Tim Peters | bf384c2 | 2003-04-06 00:11:39 +0000 | [diff] [blame] | 60 | static PyObject *gc_str = NULL; |
Tim Peters | 6fc13d9 | 2002-07-02 18:12:35 +0000 | [diff] [blame] | 61 | |
Tim Peters | 93ad66d | 2003-04-05 17:15:44 +0000 | [diff] [blame] | 62 | /* Python string used to look for __del__ attribute. */ |
| 63 | static PyObject *delstr = NULL; |
Jeremy Hylton | ce136e9 | 2003-04-04 19:59:06 +0000 | [diff] [blame] | 64 | |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 65 | /* set for debugging information */ |
| 66 | #define DEBUG_STATS (1<<0) /* print collection statistics */ |
| 67 | #define DEBUG_COLLECTABLE (1<<1) /* print collectable objects */ |
| 68 | #define DEBUG_UNCOLLECTABLE (1<<2) /* print uncollectable objects */ |
| 69 | #define DEBUG_INSTANCES (1<<3) /* print instances */ |
| 70 | #define DEBUG_OBJECTS (1<<4) /* print other objects */ |
Neil Schemenauer | 544de1e | 2000-09-22 15:22:38 +0000 | [diff] [blame] | 71 | #define DEBUG_SAVEALL (1<<5) /* save all garbage in gc.garbage */ |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 72 | #define DEBUG_LEAK DEBUG_COLLECTABLE | \ |
| 73 | DEBUG_UNCOLLECTABLE | \ |
| 74 | DEBUG_INSTANCES | \ |
Neil Schemenauer | 544de1e | 2000-09-22 15:22:38 +0000 | [diff] [blame] | 75 | DEBUG_OBJECTS | \ |
| 76 | DEBUG_SAVEALL |
Jeremy Hylton | b709df3 | 2000-09-01 02:47:25 +0000 | [diff] [blame] | 77 | static int debug; |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 78 | |
Tim Peters | 6fc13d9 | 2002-07-02 18:12:35 +0000 | [diff] [blame] | 79 | /*-------------------------------------------------------------------------- |
| 80 | gc_refs values. |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 81 | |
Tim Peters | 6fc13d9 | 2002-07-02 18:12:35 +0000 | [diff] [blame] | 82 | Between collections, every gc'ed object has one of two gc_refs values: |
| 83 | |
| 84 | GC_UNTRACKED |
| 85 | The initial state; objects returned by PyObject_GC_Malloc are in this |
| 86 | state. The object doesn't live in any generation list, and its |
| 87 | tp_traverse slot must not be called. |
| 88 | |
| 89 | GC_REACHABLE |
| 90 | The object lives in some generation list, and its tp_traverse is safe to |
| 91 | call. An object transitions to GC_REACHABLE when PyObject_GC_Track |
| 92 | is called. |
| 93 | |
| 94 | During a collection, gc_refs can temporarily take on other states: |
| 95 | |
| 96 | >= 0 |
| 97 | At the start of a collection, update_refs() copies the true refcount |
| 98 | to gc_refs, for each object in the generation being collected. |
| 99 | subtract_refs() then adjusts gc_refs so that it equals the number of |
| 100 | times an object is referenced directly from outside the generation |
| 101 | being collected. |
Martin v. Löwis | 774348c | 2002-11-09 19:54:06 +0000 | [diff] [blame] | 102 | gc_refs remains >= 0 throughout these steps. |
Tim Peters | 6fc13d9 | 2002-07-02 18:12:35 +0000 | [diff] [blame] | 103 | |
| 104 | GC_TENTATIVELY_UNREACHABLE |
| 105 | move_unreachable() then moves objects not reachable (whether directly or |
| 106 | indirectly) from outside the generation into an "unreachable" set. |
| 107 | Objects that are found to be reachable have gc_refs set to GC_REACHABLE |
| 108 | again. Objects that are found to be unreachable have gc_refs set to |
| 109 | GC_TENTATIVELY_UNREACHABLE. It's "tentatively" because the pass doing |
| 110 | this can't be sure until it ends, and GC_TENTATIVELY_UNREACHABLE may |
| 111 | transition back to GC_REACHABLE. |
| 112 | |
| 113 | Only objects with GC_TENTATIVELY_UNREACHABLE still set are candidates |
| 114 | for collection. If it's decided not to collect such an object (e.g., |
| 115 | it has a __del__ method), its gc_refs is restored to GC_REACHABLE again. |
| 116 | ---------------------------------------------------------------------------- |
| 117 | */ |
Tim Peters | ea40563 | 2002-07-02 00:52:30 +0000 | [diff] [blame] | 118 | #define GC_UNTRACKED _PyGC_REFS_UNTRACKED |
| 119 | #define GC_REACHABLE _PyGC_REFS_REACHABLE |
| 120 | #define GC_TENTATIVELY_UNREACHABLE _PyGC_REFS_TENTATIVELY_UNREACHABLE |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 121 | |
Tim Peters | 6fc13d9 | 2002-07-02 18:12:35 +0000 | [diff] [blame] | 122 | #define IS_TRACKED(o) ((AS_GC(o))->gc.gc_refs != GC_UNTRACKED) |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 123 | #define IS_REACHABLE(o) ((AS_GC(o))->gc.gc_refs == GC_REACHABLE) |
| 124 | #define IS_TENTATIVELY_UNREACHABLE(o) ( \ |
| 125 | (AS_GC(o))->gc.gc_refs == GC_TENTATIVELY_UNREACHABLE) |
Neil Schemenauer | a2b11ec | 2002-05-21 15:53:24 +0000 | [diff] [blame] | 126 | |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 127 | /*** list functions ***/ |
| 128 | |
| 129 | static void |
| 130 | gc_list_init(PyGC_Head *list) |
| 131 | { |
Tim Peters | 9e4ca10 | 2001-10-11 18:31:31 +0000 | [diff] [blame] | 132 | list->gc.gc_prev = list; |
| 133 | list->gc.gc_next = list; |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 134 | } |
| 135 | |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 136 | static int |
| 137 | gc_list_is_empty(PyGC_Head *list) |
| 138 | { |
| 139 | return (list->gc.gc_next == list); |
| 140 | } |
| 141 | |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 142 | static void |
| 143 | gc_list_append(PyGC_Head *node, PyGC_Head *list) |
| 144 | { |
Tim Peters | 9e4ca10 | 2001-10-11 18:31:31 +0000 | [diff] [blame] | 145 | node->gc.gc_next = list; |
| 146 | node->gc.gc_prev = list->gc.gc_prev; |
| 147 | node->gc.gc_prev->gc.gc_next = node; |
| 148 | list->gc.gc_prev = node; |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 149 | } |
| 150 | |
| 151 | static void |
| 152 | gc_list_remove(PyGC_Head *node) |
| 153 | { |
Tim Peters | 9e4ca10 | 2001-10-11 18:31:31 +0000 | [diff] [blame] | 154 | node->gc.gc_prev->gc.gc_next = node->gc.gc_next; |
| 155 | node->gc.gc_next->gc.gc_prev = node->gc.gc_prev; |
| 156 | node->gc.gc_next = NULL; /* object is not currently tracked */ |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 157 | } |
| 158 | |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 159 | /* append a list onto another list, from becomes an empty list */ |
| 160 | static void |
| 161 | gc_list_merge(PyGC_Head *from, PyGC_Head *to) |
| 162 | { |
| 163 | PyGC_Head *tail; |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 164 | if (!gc_list_is_empty(from)) { |
Tim Peters | 9e4ca10 | 2001-10-11 18:31:31 +0000 | [diff] [blame] | 165 | tail = to->gc.gc_prev; |
| 166 | tail->gc.gc_next = from->gc.gc_next; |
| 167 | tail->gc.gc_next->gc.gc_prev = tail; |
| 168 | to->gc.gc_prev = from->gc.gc_prev; |
| 169 | to->gc.gc_prev->gc.gc_next = to; |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 170 | } |
| 171 | gc_list_init(from); |
| 172 | } |
| 173 | |
| 174 | static long |
| 175 | gc_list_size(PyGC_Head *list) |
| 176 | { |
| 177 | PyGC_Head *gc; |
| 178 | long n = 0; |
Tim Peters | 9e4ca10 | 2001-10-11 18:31:31 +0000 | [diff] [blame] | 179 | for (gc = list->gc.gc_next; gc != list; gc = gc->gc.gc_next) { |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 180 | n++; |
| 181 | } |
| 182 | return n; |
| 183 | } |
| 184 | |
Tim Peters | 259272b | 2003-04-06 19:41:39 +0000 | [diff] [blame] | 185 | /* Append objects in a GC list to a Python list. |
| 186 | * Return 0 if all OK, < 0 if error (out of memory for list). |
| 187 | */ |
| 188 | static int |
| 189 | append_objects(PyObject *py_list, PyGC_Head *gc_list) |
| 190 | { |
| 191 | PyGC_Head *gc; |
| 192 | for (gc = gc_list->gc.gc_next; gc != gc_list; gc = gc->gc.gc_next) { |
| 193 | PyObject *op = FROM_GC(gc); |
| 194 | if (op != py_list) { |
| 195 | if (PyList_Append(py_list, op)) { |
| 196 | return -1; /* exception */ |
| 197 | } |
| 198 | } |
| 199 | } |
| 200 | return 0; |
| 201 | } |
| 202 | |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 203 | /*** end of list stuff ***/ |
| 204 | |
| 205 | |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 206 | /* Set all gc_refs = ob_refcnt. After this, gc_refs is > 0 for all objects |
| 207 | * in containers, and is GC_REACHABLE for all tracked gc objects not in |
| 208 | * containers. |
Tim Peters | 8839617 | 2002-06-30 17:56:40 +0000 | [diff] [blame] | 209 | */ |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 210 | static void |
| 211 | update_refs(PyGC_Head *containers) |
| 212 | { |
Tim Peters | 9e4ca10 | 2001-10-11 18:31:31 +0000 | [diff] [blame] | 213 | PyGC_Head *gc = containers->gc.gc_next; |
Tim Peters | ea40563 | 2002-07-02 00:52:30 +0000 | [diff] [blame] | 214 | for (; gc != containers; gc = gc->gc.gc_next) { |
| 215 | assert(gc->gc.gc_refs == GC_REACHABLE); |
Tim Peters | 9e4ca10 | 2001-10-11 18:31:31 +0000 | [diff] [blame] | 216 | gc->gc.gc_refs = FROM_GC(gc)->ob_refcnt; |
Tim Peters | 780c497 | 2003-11-14 00:01:17 +0000 | [diff] [blame] | 217 | /* Python's cyclic gc should never see an incoming refcount |
| 218 | * of 0: if something decref'ed to 0, it should have been |
| 219 | * deallocated immediately at that time. |
| 220 | * Possible cause (if the assert triggers): a tp_dealloc |
| 221 | * routine left a gc-aware object tracked during its teardown |
| 222 | * phase, and did something-- or allowed something to happen -- |
| 223 | * that called back into Python. gc can trigger then, and may |
| 224 | * see the still-tracked dying object. Before this assert |
| 225 | * was added, such mistakes went on to allow gc to try to |
| 226 | * delete the object again. In a debug build, that caused |
| 227 | * a mysterious segfault, when _Py_ForgetReference tried |
| 228 | * to remove the object from the doubly-linked list of all |
| 229 | * objects a second time. In a release build, an actual |
| 230 | * double deallocation occurred, which leads to corruption |
| 231 | * of the allocator's internal bookkeeping pointers. That's |
| 232 | * so serious that maybe this should be a release-build |
| 233 | * check instead of an assert? |
| 234 | */ |
| 235 | assert(gc->gc.gc_refs != 0); |
Tim Peters | ea40563 | 2002-07-02 00:52:30 +0000 | [diff] [blame] | 236 | } |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 237 | } |
| 238 | |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 239 | /* A traversal callback for subtract_refs. */ |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 240 | static int |
| 241 | visit_decref(PyObject *op, void *data) |
| 242 | { |
Tim Peters | 93cd83e | 2002-06-30 21:31:03 +0000 | [diff] [blame] | 243 | assert(op != NULL); |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 244 | if (PyObject_IS_GC(op)) { |
| 245 | PyGC_Head *gc = AS_GC(op); |
| 246 | /* We're only interested in gc_refs for objects in the |
| 247 | * generation being collected, which can be recognized |
| 248 | * because only they have positive gc_refs. |
| 249 | */ |
Tim Peters | aab713b | 2002-07-02 22:15:28 +0000 | [diff] [blame] | 250 | assert(gc->gc.gc_refs != 0); /* else refcount was too small */ |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 251 | if (gc->gc.gc_refs > 0) |
| 252 | gc->gc.gc_refs--; |
| 253 | } |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 254 | return 0; |
| 255 | } |
| 256 | |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 257 | /* Subtract internal references from gc_refs. After this, gc_refs is >= 0 |
| 258 | * for all objects in containers, and is GC_REACHABLE for all tracked gc |
| 259 | * objects not in containers. The ones with gc_refs > 0 are directly |
| 260 | * reachable from outside containers, and so can't be collected. |
| 261 | */ |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 262 | static void |
| 263 | subtract_refs(PyGC_Head *containers) |
| 264 | { |
| 265 | traverseproc traverse; |
Tim Peters | 9e4ca10 | 2001-10-11 18:31:31 +0000 | [diff] [blame] | 266 | PyGC_Head *gc = containers->gc.gc_next; |
| 267 | for (; gc != containers; gc=gc->gc.gc_next) { |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 268 | traverse = FROM_GC(gc)->ob_type->tp_traverse; |
| 269 | (void) traverse(FROM_GC(gc), |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 270 | (visitproc)visit_decref, |
| 271 | NULL); |
| 272 | } |
| 273 | } |
| 274 | |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 275 | /* A traversal callback for move_unreachable. */ |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 276 | static int |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 277 | visit_reachable(PyObject *op, PyGC_Head *reachable) |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 278 | { |
Tim Peters | ea40563 | 2002-07-02 00:52:30 +0000 | [diff] [blame] | 279 | if (PyObject_IS_GC(op)) { |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 280 | PyGC_Head *gc = AS_GC(op); |
| 281 | const int gc_refs = gc->gc.gc_refs; |
| 282 | |
| 283 | if (gc_refs == 0) { |
| 284 | /* This is in move_unreachable's 'young' list, but |
| 285 | * the traversal hasn't yet gotten to it. All |
| 286 | * we need to do is tell move_unreachable that it's |
| 287 | * reachable. |
| 288 | */ |
| 289 | gc->gc.gc_refs = 1; |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 290 | } |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 291 | else if (gc_refs == GC_TENTATIVELY_UNREACHABLE) { |
| 292 | /* This had gc_refs = 0 when move_unreachable got |
| 293 | * to it, but turns out it's reachable after all. |
| 294 | * Move it back to move_unreachable's 'young' list, |
| 295 | * and move_unreachable will eventually get to it |
| 296 | * again. |
| 297 | */ |
| 298 | gc_list_remove(gc); |
| 299 | gc_list_append(gc, reachable); |
| 300 | gc->gc.gc_refs = 1; |
| 301 | } |
| 302 | /* Else there's nothing to do. |
| 303 | * If gc_refs > 0, it must be in move_unreachable's 'young' |
| 304 | * list, and move_unreachable will eventually get to it. |
| 305 | * If gc_refs == GC_REACHABLE, it's either in some other |
| 306 | * generation so we don't care about it, or move_unreachable |
Tim Peters | 6fc13d9 | 2002-07-02 18:12:35 +0000 | [diff] [blame] | 307 | * already dealt with it. |
Tim Peters | ea40563 | 2002-07-02 00:52:30 +0000 | [diff] [blame] | 308 | * If gc_refs == GC_UNTRACKED, it must be ignored. |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 309 | */ |
Tim Peters | ea40563 | 2002-07-02 00:52:30 +0000 | [diff] [blame] | 310 | else { |
| 311 | assert(gc_refs > 0 |
| 312 | || gc_refs == GC_REACHABLE |
| 313 | || gc_refs == GC_UNTRACKED); |
| 314 | } |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 315 | } |
| 316 | return 0; |
| 317 | } |
| 318 | |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 319 | /* Move the unreachable objects from young to unreachable. After this, |
| 320 | * all objects in young have gc_refs = GC_REACHABLE, and all objects in |
| 321 | * unreachable have gc_refs = GC_TENTATIVELY_UNREACHABLE. All tracked |
| 322 | * gc objects not in young or unreachable still have gc_refs = GC_REACHABLE. |
| 323 | * All objects in young after this are directly or indirectly reachable |
| 324 | * from outside the original young; and all objects in unreachable are |
| 325 | * not. |
Tim Peters | 8839617 | 2002-06-30 17:56:40 +0000 | [diff] [blame] | 326 | */ |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 327 | static void |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 328 | move_unreachable(PyGC_Head *young, PyGC_Head *unreachable) |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 329 | { |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 330 | PyGC_Head *gc = young->gc.gc_next; |
| 331 | |
| 332 | /* Invariants: all objects "to the left" of us in young have gc_refs |
| 333 | * = GC_REACHABLE, and are indeed reachable (directly or indirectly) |
| 334 | * from outside the young list as it was at entry. All other objects |
| 335 | * from the original young "to the left" of us are in unreachable now, |
| 336 | * and have gc_refs = GC_TENTATIVELY_UNREACHABLE. All objects to the |
| 337 | * left of us in 'young' now have been scanned, and no objects here |
| 338 | * or to the right have been scanned yet. |
| 339 | */ |
| 340 | |
| 341 | while (gc != young) { |
| 342 | PyGC_Head *next; |
| 343 | |
Tim Peters | 6fc13d9 | 2002-07-02 18:12:35 +0000 | [diff] [blame] | 344 | if (gc->gc.gc_refs) { |
| 345 | /* gc is definitely reachable from outside the |
| 346 | * original 'young'. Mark it as such, and traverse |
| 347 | * its pointers to find any other objects that may |
| 348 | * be directly reachable from it. Note that the |
| 349 | * call to tp_traverse may append objects to young, |
| 350 | * so we have to wait until it returns to determine |
| 351 | * the next object to visit. |
| 352 | */ |
| 353 | PyObject *op = FROM_GC(gc); |
| 354 | traverseproc traverse = op->ob_type->tp_traverse; |
| 355 | assert(gc->gc.gc_refs > 0); |
| 356 | gc->gc.gc_refs = GC_REACHABLE; |
| 357 | (void) traverse(op, |
| 358 | (visitproc)visit_reachable, |
| 359 | (void *)young); |
| 360 | next = gc->gc.gc_next; |
| 361 | } |
| 362 | else { |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 363 | /* This *may* be unreachable. To make progress, |
| 364 | * assume it is. gc isn't directly reachable from |
| 365 | * any object we've already traversed, but may be |
| 366 | * reachable from an object we haven't gotten to yet. |
| 367 | * visit_reachable will eventually move gc back into |
| 368 | * young if that's so, and we'll see it again. |
| 369 | */ |
| 370 | next = gc->gc.gc_next; |
| 371 | gc_list_remove(gc); |
| 372 | gc_list_append(gc, unreachable); |
| 373 | gc->gc.gc_refs = GC_TENTATIVELY_UNREACHABLE; |
| 374 | } |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 375 | gc = next; |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 376 | } |
| 377 | } |
| 378 | |
Tim Peters | 86b993b | 2003-04-05 17:35:54 +0000 | [diff] [blame] | 379 | /* Return true if object has a finalization method. |
| 380 | * CAUTION: An instance of an old-style class has to be checked for a |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 381 | *__del__ method, and earlier versions of this used to call PyObject_HasAttr, |
| 382 | * which in turn could call the class's __getattr__ hook (if any). That |
| 383 | * could invoke arbitrary Python code, mutating the object graph in arbitrary |
| 384 | * ways, and that was the source of some excruciatingly subtle bugs. |
Tim Peters | 86b993b | 2003-04-05 17:35:54 +0000 | [diff] [blame] | 385 | */ |
Neil Schemenauer | a765c12 | 2001-11-01 17:35:23 +0000 | [diff] [blame] | 386 | static int |
| 387 | has_finalizer(PyObject *op) |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 388 | { |
Tim Peters | 86b993b | 2003-04-05 17:35:54 +0000 | [diff] [blame] | 389 | if (PyInstance_Check(op)) { |
Tim Peters | 86b993b | 2003-04-05 17:35:54 +0000 | [diff] [blame] | 390 | assert(delstr != NULL); |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 391 | return _PyInstance_Lookup(op, delstr) != NULL; |
Tim Peters | 86b993b | 2003-04-05 17:35:54 +0000 | [diff] [blame] | 392 | } |
| 393 | else if (PyType_HasFeature(op->ob_type, Py_TPFLAGS_HEAPTYPE)) |
| 394 | return op->ob_type->tp_del != NULL; |
| 395 | else |
| 396 | return 0; |
Neil Schemenauer | a765c12 | 2001-11-01 17:35:23 +0000 | [diff] [blame] | 397 | } |
| 398 | |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 399 | /* Move the objects in unreachable with __del__ methods into `finalizers`. |
| 400 | * Objects moved into `finalizers` have gc_refs set to GC_REACHABLE; the |
| 401 | * objects remaining in unreachable are left at GC_TENTATIVELY_UNREACHABLE. |
Jeremy Hylton | ce136e9 | 2003-04-04 19:59:06 +0000 | [diff] [blame] | 402 | */ |
Neil Schemenauer | a765c12 | 2001-11-01 17:35:23 +0000 | [diff] [blame] | 403 | static void |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 404 | move_finalizers(PyGC_Head *unreachable, PyGC_Head *finalizers) |
Neil Schemenauer | a765c12 | 2001-11-01 17:35:23 +0000 | [diff] [blame] | 405 | { |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 406 | PyGC_Head *gc; |
| 407 | PyGC_Head *next; |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 408 | |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 409 | /* March over unreachable. Move objects with finalizers into |
| 410 | * `finalizers`. |
| 411 | */ |
| 412 | for (gc = unreachable->gc.gc_next; gc != unreachable; gc = next) { |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 413 | PyObject *op = FROM_GC(gc); |
Jeremy Hylton | ce136e9 | 2003-04-04 19:59:06 +0000 | [diff] [blame] | 414 | |
Tim Peters | f6ae7a4 | 2003-04-05 18:40:50 +0000 | [diff] [blame] | 415 | assert(IS_TENTATIVELY_UNREACHABLE(op)); |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 416 | next = gc->gc.gc_next; |
Tim Peters | f6ae7a4 | 2003-04-05 18:40:50 +0000 | [diff] [blame] | 417 | |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 418 | if (has_finalizer(op)) { |
Tim Peters | f6ae7a4 | 2003-04-05 18:40:50 +0000 | [diff] [blame] | 419 | gc_list_remove(gc); |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 420 | gc_list_append(gc, finalizers); |
| 421 | gc->gc.gc_refs = GC_REACHABLE; |
Jeremy Hylton | ce136e9 | 2003-04-04 19:59:06 +0000 | [diff] [blame] | 422 | } |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 423 | } |
| 424 | } |
| 425 | |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 426 | /* A traversal callback for move_finalizer_reachable. */ |
| 427 | static int |
| 428 | visit_move(PyObject *op, PyGC_Head *tolist) |
| 429 | { |
| 430 | if (PyObject_IS_GC(op)) { |
Tim Peters | ea40563 | 2002-07-02 00:52:30 +0000 | [diff] [blame] | 431 | if (IS_TENTATIVELY_UNREACHABLE(op)) { |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 432 | PyGC_Head *gc = AS_GC(op); |
| 433 | gc_list_remove(gc); |
| 434 | gc_list_append(gc, tolist); |
| 435 | gc->gc.gc_refs = GC_REACHABLE; |
| 436 | } |
| 437 | } |
| 438 | return 0; |
| 439 | } |
| 440 | |
| 441 | /* Move objects that are reachable from finalizers, from the unreachable set |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 442 | * into finalizers set. |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 443 | */ |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 444 | static void |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 445 | move_finalizer_reachable(PyGC_Head *finalizers) |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 446 | { |
| 447 | traverseproc traverse; |
Tim Peters | 9e4ca10 | 2001-10-11 18:31:31 +0000 | [diff] [blame] | 448 | PyGC_Head *gc = finalizers->gc.gc_next; |
Tim Peters | bf384c2 | 2003-04-06 00:11:39 +0000 | [diff] [blame] | 449 | for (; gc != finalizers; gc = gc->gc.gc_next) { |
| 450 | /* Note that the finalizers list may grow during this. */ |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 451 | traverse = FROM_GC(gc)->ob_type->tp_traverse; |
Tim Peters | 8839617 | 2002-06-30 17:56:40 +0000 | [diff] [blame] | 452 | (void) traverse(FROM_GC(gc), |
Tim Peters | bf384c2 | 2003-04-06 00:11:39 +0000 | [diff] [blame] | 453 | (visitproc)visit_move, |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 454 | (void *)finalizers); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 455 | } |
| 456 | } |
| 457 | |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 458 | /* Clear all weakrefs to unreachable objects, and if such a weakref has a |
| 459 | * callback, invoke it if necessary. Note that it's possible for such |
| 460 | * weakrefs to be outside the unreachable set -- indeed, those are precisely |
| 461 | * the weakrefs whose callbacks must be invoked. See gc_weakref.txt for |
| 462 | * overview & some details. Some weakrefs with callbacks may be reclaimed |
| 463 | * directly by this routine; the number reclaimed is the return value. Other |
| 464 | * weakrefs with callbacks may be moved into the `old` generation. Objects |
| 465 | * moved into `old` have gc_refs set to GC_REACHABLE; the objects remaining in |
| 466 | * unreachable are left at GC_TENTATIVELY_UNREACHABLE. When this returns, |
| 467 | * no object in `unreachable` is weakly referenced anymore. |
Tim Peters | 403a203 | 2003-11-20 21:21:46 +0000 | [diff] [blame] | 468 | */ |
| 469 | static int |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 470 | handle_weakrefs(PyGC_Head *unreachable, PyGC_Head *old) |
Tim Peters | 403a203 | 2003-11-20 21:21:46 +0000 | [diff] [blame] | 471 | { |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 472 | PyGC_Head *gc; |
| 473 | PyObject *op; /* generally FROM_GC(gc) */ |
| 474 | PyWeakReference *wr; /* generally a cast of op */ |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 475 | PyGC_Head wrcb_to_call; /* weakrefs with callbacks to call */ |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 476 | PyGC_Head *next; |
Tim Peters | 403a203 | 2003-11-20 21:21:46 +0000 | [diff] [blame] | 477 | int num_freed = 0; |
| 478 | |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 479 | gc_list_init(&wrcb_to_call); |
Tim Peters | 403a203 | 2003-11-20 21:21:46 +0000 | [diff] [blame] | 480 | |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 481 | /* Clear all weakrefs to the objects in unreachable. If such a weakref |
| 482 | * also has a callback, move it into `wrcb_to_call` if the callback |
Tim Peters | cc2a866 | 2004-10-31 22:12:43 +0000 | [diff] [blame^] | 483 | * needs to be invoked. Note that we cannot invoke any callbacks until |
| 484 | * all weakrefs to unreachable objects are cleared, lest the callback |
| 485 | * resurrect an unreachable object via a still-active weakref. We |
| 486 | * make another pass over wrcb_to_call, invoking callbacks, after this |
| 487 | * pass completes. |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 488 | */ |
| 489 | for (gc = unreachable->gc.gc_next; gc != unreachable; gc = next) { |
| 490 | PyWeakReference **wrlist; |
| 491 | |
| 492 | op = FROM_GC(gc); |
| 493 | assert(IS_TENTATIVELY_UNREACHABLE(op)); |
| 494 | next = gc->gc.gc_next; |
| 495 | |
| 496 | if (! PyType_SUPPORTS_WEAKREFS(op->ob_type)) |
| 497 | continue; |
| 498 | |
| 499 | /* It supports weakrefs. Does it have any? */ |
| 500 | wrlist = (PyWeakReference **) |
| 501 | PyObject_GET_WEAKREFS_LISTPTR(op); |
| 502 | |
| 503 | /* `op` may have some weakrefs. March over the list, clear |
| 504 | * all the weakrefs, and move the weakrefs with callbacks |
Tim Peters | cc2a866 | 2004-10-31 22:12:43 +0000 | [diff] [blame^] | 505 | * that must be called into wrcb_to_call. |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 506 | */ |
| 507 | for (wr = *wrlist; wr != NULL; wr = *wrlist) { |
| 508 | PyGC_Head *wrasgc; /* AS_GC(wr) */ |
| 509 | |
| 510 | /* _PyWeakref_ClearRef clears the weakref but leaves |
| 511 | * the callback pointer intact. Obscure: it also |
| 512 | * changes *wrlist. |
| 513 | */ |
| 514 | assert(wr->wr_object == op); |
| 515 | _PyWeakref_ClearRef(wr); |
| 516 | assert(wr->wr_object == Py_None); |
| 517 | if (wr->wr_callback == NULL) |
| 518 | continue; /* no callback */ |
| 519 | |
| 520 | /* Headache time. `op` is going away, and is weakly referenced by |
| 521 | * `wr`, which has a callback. Should the callback be invoked? If wr |
| 522 | * is also trash, no: |
| 523 | * |
| 524 | * 1. There's no need to call it. The object and the weakref are |
| 525 | * both going away, so it's legitimate to pretend the weakref is |
| 526 | * going away first. The user has to ensure a weakref outlives its |
| 527 | * referent if they want a guarantee that the wr callback will get |
| 528 | * invoked. |
| 529 | * |
| 530 | * 2. It may be catastrophic to call it. If the callback is also in |
| 531 | * cyclic trash (CT), then although the CT is unreachable from |
| 532 | * outside the current generation, CT may be reachable from the |
| 533 | * callback. Then the callback could resurrect insane objects. |
| 534 | * |
| 535 | * Since the callback is never needed and may be unsafe in this case, |
Tim Peters | cc2a866 | 2004-10-31 22:12:43 +0000 | [diff] [blame^] | 536 | * wr is simply left in the unreachable set. Note that because we |
| 537 | * already called _PyWeakref_ClearRef(wr), its callback will never |
| 538 | * trigger. |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 539 | * |
| 540 | * OTOH, if wr isn't part of CT, we should invoke the callback: the |
| 541 | * weakref outlived the trash. Note that since wr isn't CT in this |
| 542 | * case, its callback can't be CT either -- wr acted as an external |
| 543 | * root to this generation, and therefore its callback did too. So |
| 544 | * nothing in CT is reachable from the callback either, so it's hard |
| 545 | * to imagine how calling it later could create a problem for us. wr |
| 546 | * is moved to wrcb_to_call in this case. |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 547 | */ |
Tim Peters | cc2a866 | 2004-10-31 22:12:43 +0000 | [diff] [blame^] | 548 | if (IS_TENTATIVELY_UNREACHABLE(wr)) |
| 549 | continue; |
| 550 | assert(IS_REACHABLE(wr)); |
| 551 | |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 552 | /* Create a new reference so that wr can't go away |
| 553 | * before we can process it again. |
| 554 | */ |
| 555 | Py_INCREF(wr); |
| 556 | |
Tim Peters | cc2a866 | 2004-10-31 22:12:43 +0000 | [diff] [blame^] | 557 | /* Move wr to wrcb_to_call, for the next pass. */ |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 558 | wrasgc = AS_GC(wr); |
Tim Peters | cc2a866 | 2004-10-31 22:12:43 +0000 | [diff] [blame^] | 559 | assert(wrasgc != next); /* wrasgc is reachable, but |
| 560 | next isn't, so they can't |
| 561 | be the same */ |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 562 | gc_list_remove(wrasgc); |
Tim Peters | cc2a866 | 2004-10-31 22:12:43 +0000 | [diff] [blame^] | 563 | gc_list_append(wrasgc, &wrcb_to_call); |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 564 | } |
| 565 | } |
| 566 | |
Tim Peters | cc2a866 | 2004-10-31 22:12:43 +0000 | [diff] [blame^] | 567 | /* Invoke the callbacks we decided to honor. It's safe to invoke them |
| 568 | * because they can't reference unreachable objects. |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 569 | */ |
| 570 | while (! gc_list_is_empty(&wrcb_to_call)) { |
| 571 | PyObject *temp; |
| 572 | PyObject *callback; |
| 573 | |
| 574 | gc = wrcb_to_call.gc.gc_next; |
| 575 | op = FROM_GC(gc); |
| 576 | assert(IS_REACHABLE(op)); |
| 577 | assert(PyWeakref_Check(op)); |
| 578 | wr = (PyWeakReference *)op; |
| 579 | callback = wr->wr_callback; |
| 580 | assert(callback != NULL); |
| 581 | |
| 582 | /* copy-paste of weakrefobject.c's handle_callback() */ |
| 583 | temp = PyObject_CallFunction(callback, "O", wr); |
| 584 | if (temp == NULL) |
| 585 | PyErr_WriteUnraisable(callback); |
| 586 | else |
| 587 | Py_DECREF(temp); |
| 588 | |
| 589 | /* Give up the reference we created in the first pass. When |
| 590 | * op's refcount hits 0 (which it may or may not do right now), |
Tim Peters | cc2a866 | 2004-10-31 22:12:43 +0000 | [diff] [blame^] | 591 | * op's tp_dealloc will decref op->wr_callback too. Note |
| 592 | * that the refcount probably will hit 0 now, and because this |
| 593 | * weakref was reachable to begin with, gc didn't already |
| 594 | * add it to its count of freed objects. Example: a reachable |
| 595 | * weak value dict maps some key to this reachable weakref. |
| 596 | * The callback removes this key->weakref mapping from the |
| 597 | * dict, leaving no other references to the weakref (excepting |
| 598 | * ours). |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 599 | */ |
| 600 | Py_DECREF(op); |
| 601 | if (wrcb_to_call.gc.gc_next == gc) { |
| 602 | /* object is still alive -- move it */ |
| 603 | gc_list_remove(gc); |
| 604 | gc_list_append(gc, old); |
| 605 | } |
| 606 | else |
| 607 | ++num_freed; |
| 608 | } |
| 609 | |
Tim Peters | 403a203 | 2003-11-20 21:21:46 +0000 | [diff] [blame] | 610 | return num_freed; |
| 611 | } |
| 612 | |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 613 | static void |
Jeremy Hylton | 0625777 | 2000-08-31 15:10:24 +0000 | [diff] [blame] | 614 | debug_instance(char *msg, PyInstanceObject *inst) |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 615 | { |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 616 | char *cname; |
Neil Schemenauer | a765c12 | 2001-11-01 17:35:23 +0000 | [diff] [blame] | 617 | /* simple version of instance_repr */ |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 618 | PyObject *classname = inst->in_class->cl_name; |
| 619 | if (classname != NULL && PyString_Check(classname)) |
| 620 | cname = PyString_AsString(classname); |
| 621 | else |
| 622 | cname = "?"; |
Jeremy Hylton | 0625777 | 2000-08-31 15:10:24 +0000 | [diff] [blame] | 623 | PySys_WriteStderr("gc: %.100s <%.100s instance at %p>\n", |
| 624 | msg, cname, inst); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 625 | } |
| 626 | |
| 627 | static void |
Jeremy Hylton | 0625777 | 2000-08-31 15:10:24 +0000 | [diff] [blame] | 628 | debug_cycle(char *msg, PyObject *op) |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 629 | { |
| 630 | if ((debug & DEBUG_INSTANCES) && PyInstance_Check(op)) { |
Jeremy Hylton | 0625777 | 2000-08-31 15:10:24 +0000 | [diff] [blame] | 631 | debug_instance(msg, (PyInstanceObject *)op); |
Neil Schemenauer | 544de1e | 2000-09-22 15:22:38 +0000 | [diff] [blame] | 632 | } |
| 633 | else if (debug & DEBUG_OBJECTS) { |
Jeremy Hylton | 0625777 | 2000-08-31 15:10:24 +0000 | [diff] [blame] | 634 | PySys_WriteStderr("gc: %.100s <%.100s %p>\n", |
| 635 | msg, op->ob_type->tp_name, op); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 636 | } |
| 637 | } |
| 638 | |
Tim Peters | bf384c2 | 2003-04-06 00:11:39 +0000 | [diff] [blame] | 639 | /* Handle uncollectable garbage (cycles with finalizers, and stuff reachable |
| 640 | * only from such cycles). |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 641 | * If DEBUG_SAVEALL, all objects in finalizers are appended to the module |
| 642 | * garbage list (a Python list), else only the objects in finalizers with |
| 643 | * __del__ methods are appended to garbage. All objects in finalizers are |
| 644 | * merged into the old list regardless. |
Tim Peters | 259272b | 2003-04-06 19:41:39 +0000 | [diff] [blame] | 645 | * Returns 0 if all OK, <0 on error (out of memory to grow the garbage list). |
| 646 | * The finalizers list is made empty on a successful return. |
Tim Peters | bf384c2 | 2003-04-06 00:11:39 +0000 | [diff] [blame] | 647 | */ |
Tim Peters | 259272b | 2003-04-06 19:41:39 +0000 | [diff] [blame] | 648 | static int |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 649 | handle_finalizers(PyGC_Head *finalizers, PyGC_Head *old) |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 650 | { |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 651 | PyGC_Head *gc = finalizers->gc.gc_next; |
| 652 | |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 653 | if (garbage == NULL) { |
| 654 | garbage = PyList_New(0); |
Tim Peters | bf384c2 | 2003-04-06 00:11:39 +0000 | [diff] [blame] | 655 | if (garbage == NULL) |
| 656 | Py_FatalError("gc couldn't create gc.garbage list"); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 657 | } |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 658 | for (; gc != finalizers; gc = gc->gc.gc_next) { |
| 659 | PyObject *op = FROM_GC(gc); |
| 660 | |
| 661 | if ((debug & DEBUG_SAVEALL) || has_finalizer(op)) { |
| 662 | if (PyList_Append(garbage, op) < 0) |
| 663 | return -1; |
| 664 | } |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 665 | } |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 666 | |
Tim Peters | 259272b | 2003-04-06 19:41:39 +0000 | [diff] [blame] | 667 | gc_list_merge(finalizers, old); |
| 668 | return 0; |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 669 | } |
| 670 | |
Neil Schemenauer | 544de1e | 2000-09-22 15:22:38 +0000 | [diff] [blame] | 671 | /* Break reference cycles by clearing the containers involved. This is |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 672 | * tricky business as the lists can be changing and we don't know which |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 673 | * objects may be freed. It is possible I screwed something up here. |
| 674 | */ |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 675 | static void |
Jeremy Hylton | ce136e9 | 2003-04-04 19:59:06 +0000 | [diff] [blame] | 676 | delete_garbage(PyGC_Head *collectable, PyGC_Head *old) |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 677 | { |
| 678 | inquiry clear; |
| 679 | |
Jeremy Hylton | ce136e9 | 2003-04-04 19:59:06 +0000 | [diff] [blame] | 680 | while (!gc_list_is_empty(collectable)) { |
| 681 | PyGC_Head *gc = collectable->gc.gc_next; |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 682 | PyObject *op = FROM_GC(gc); |
Tim Peters | 8839617 | 2002-06-30 17:56:40 +0000 | [diff] [blame] | 683 | |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 684 | assert(IS_TENTATIVELY_UNREACHABLE(op)); |
Neil Schemenauer | 544de1e | 2000-09-22 15:22:38 +0000 | [diff] [blame] | 685 | if (debug & DEBUG_SAVEALL) { |
| 686 | PyList_Append(garbage, op); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 687 | } |
Neil Schemenauer | 544de1e | 2000-09-22 15:22:38 +0000 | [diff] [blame] | 688 | else { |
| 689 | if ((clear = op->ob_type->tp_clear) != NULL) { |
| 690 | Py_INCREF(op); |
Jeremy Hylton | 8a13518 | 2002-06-06 23:23:55 +0000 | [diff] [blame] | 691 | clear(op); |
Neil Schemenauer | 544de1e | 2000-09-22 15:22:38 +0000 | [diff] [blame] | 692 | Py_DECREF(op); |
| 693 | } |
| 694 | } |
Jeremy Hylton | ce136e9 | 2003-04-04 19:59:06 +0000 | [diff] [blame] | 695 | if (collectable->gc.gc_next == gc) { |
Neil Schemenauer | 544de1e | 2000-09-22 15:22:38 +0000 | [diff] [blame] | 696 | /* object is still alive, move it, it may die later */ |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 697 | gc_list_remove(gc); |
| 698 | gc_list_append(gc, old); |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 699 | gc->gc.gc_refs = GC_REACHABLE; |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 700 | } |
| 701 | } |
| 702 | } |
| 703 | |
| 704 | /* This is the main function. Read this to understand how the |
| 705 | * collection process works. */ |
| 706 | static long |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 707 | collect(int generation) |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 708 | { |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 709 | int i; |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 710 | long m = 0; /* # objects collected */ |
| 711 | long n = 0; /* # unreachable objects that couldn't be collected */ |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 712 | PyGC_Head *young; /* the generation we are examining */ |
| 713 | PyGC_Head *old; /* next older generation */ |
Tim Peters | 403a203 | 2003-11-20 21:21:46 +0000 | [diff] [blame] | 714 | PyGC_Head unreachable; /* non-problematic unreachable trash */ |
| 715 | PyGC_Head finalizers; /* objects with, & reachable from, __del__ */ |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 716 | PyGC_Head *gc; |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 717 | |
Tim Peters | 93ad66d | 2003-04-05 17:15:44 +0000 | [diff] [blame] | 718 | if (delstr == NULL) { |
| 719 | delstr = PyString_InternFromString("__del__"); |
| 720 | if (delstr == NULL) |
| 721 | Py_FatalError("gc couldn't allocate \"__del__\""); |
| 722 | } |
| 723 | |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 724 | if (debug & DEBUG_STATS) { |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 725 | PySys_WriteStderr("gc: collecting generation %d...\n", |
| 726 | generation); |
| 727 | PySys_WriteStderr("gc: objects in each generation:"); |
| 728 | for (i = 0; i < NUM_GENERATIONS; i++) { |
| 729 | PySys_WriteStderr(" %ld", gc_list_size(GEN_HEAD(i))); |
| 730 | } |
| 731 | PySys_WriteStderr("\n"); |
| 732 | } |
| 733 | |
| 734 | /* update collection and allocation counters */ |
| 735 | if (generation+1 < NUM_GENERATIONS) |
| 736 | generations[generation+1].count += 1; |
| 737 | for (i = 0; i <= generation; i++) |
Neil Schemenauer | c905164 | 2002-06-28 19:16:04 +0000 | [diff] [blame] | 738 | generations[i].count = 0; |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 739 | |
| 740 | /* merge younger generations with one we are currently collecting */ |
| 741 | for (i = 0; i < generation; i++) { |
| 742 | gc_list_merge(GEN_HEAD(i), GEN_HEAD(generation)); |
| 743 | } |
| 744 | |
| 745 | /* handy references */ |
| 746 | young = GEN_HEAD(generation); |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 747 | if (generation < NUM_GENERATIONS-1) |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 748 | old = GEN_HEAD(generation+1); |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 749 | else |
| 750 | old = young; |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 751 | |
| 752 | /* Using ob_refcnt and gc_refs, calculate which objects in the |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 753 | * container set are reachable from outside the set (i.e., have a |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 754 | * refcount greater than 0 when all the references within the |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 755 | * set are taken into account). |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 756 | */ |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 757 | update_refs(young); |
| 758 | subtract_refs(young); |
| 759 | |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 760 | /* Leave everything reachable from outside young in young, and move |
| 761 | * everything else (in young) to unreachable. |
| 762 | * NOTE: This used to move the reachable objects into a reachable |
| 763 | * set instead. But most things usually turn out to be reachable, |
| 764 | * so it's more efficient to move the unreachable things. |
| 765 | */ |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 766 | gc_list_init(&unreachable); |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 767 | move_unreachable(young, &unreachable); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 768 | |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 769 | /* Move reachable objects to next generation. */ |
| 770 | if (young != old) |
| 771 | gc_list_merge(young, old); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 772 | |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 773 | /* All objects in unreachable are trash, but objects reachable from |
| 774 | * finalizers can't safely be deleted. Python programmers should take |
| 775 | * care not to create such things. For Python, finalizers means |
Tim Peters | 403a203 | 2003-11-20 21:21:46 +0000 | [diff] [blame] | 776 | * instance objects with __del__ methods. Weakrefs with callbacks |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 777 | * can also call arbitrary Python code but they will be dealt with by |
| 778 | * handle_weakrefs(). |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 779 | */ |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 780 | gc_list_init(&finalizers); |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 781 | move_finalizers(&unreachable, &finalizers); |
Tim Peters | bf384c2 | 2003-04-06 00:11:39 +0000 | [diff] [blame] | 782 | /* finalizers contains the unreachable objects with a finalizer; |
Tim Peters | 403a203 | 2003-11-20 21:21:46 +0000 | [diff] [blame] | 783 | * unreachable objects reachable *from* those are also uncollectable, |
| 784 | * and we move those into the finalizers list too. |
Tim Peters | bf384c2 | 2003-04-06 00:11:39 +0000 | [diff] [blame] | 785 | */ |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 786 | move_finalizer_reachable(&finalizers); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 787 | |
| 788 | /* Collect statistics on collectable objects found and print |
Tim Peters | 403a203 | 2003-11-20 21:21:46 +0000 | [diff] [blame] | 789 | * debugging information. |
| 790 | */ |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 791 | for (gc = unreachable.gc.gc_next; gc != &unreachable; |
Tim Peters | 9e4ca10 | 2001-10-11 18:31:31 +0000 | [diff] [blame] | 792 | gc = gc->gc.gc_next) { |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 793 | m++; |
Jeremy Hylton | 0625777 | 2000-08-31 15:10:24 +0000 | [diff] [blame] | 794 | if (debug & DEBUG_COLLECTABLE) { |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 795 | debug_cycle("collectable", FROM_GC(gc)); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 796 | } |
| 797 | } |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 798 | |
| 799 | /* Clear weakrefs and invoke callbacks as necessary. */ |
| 800 | m += handle_weakrefs(&unreachable, old); |
| 801 | |
Tim Peters | fb2ab4d | 2003-04-07 22:41:24 +0000 | [diff] [blame] | 802 | /* Call tp_clear on objects in the unreachable set. This will cause |
| 803 | * the reference cycles to be broken. It may also cause some objects |
| 804 | * in finalizers to be freed. |
| 805 | */ |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 806 | delete_garbage(&unreachable, old); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 807 | |
| 808 | /* Collect statistics on uncollectable objects found and print |
| 809 | * debugging information. */ |
Tim Peters | 50c61d5 | 2003-04-06 01:50:50 +0000 | [diff] [blame] | 810 | for (gc = finalizers.gc.gc_next; |
Tim Peters | bf384c2 | 2003-04-06 00:11:39 +0000 | [diff] [blame] | 811 | gc != &finalizers; |
| 812 | gc = gc->gc.gc_next) { |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 813 | n++; |
Tim Peters | bf384c2 | 2003-04-06 00:11:39 +0000 | [diff] [blame] | 814 | if (debug & DEBUG_UNCOLLECTABLE) |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 815 | debug_cycle("uncollectable", FROM_GC(gc)); |
Tim Peters | bf384c2 | 2003-04-06 00:11:39 +0000 | [diff] [blame] | 816 | } |
Jeremy Hylton | 0625777 | 2000-08-31 15:10:24 +0000 | [diff] [blame] | 817 | if (debug & DEBUG_STATS) { |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 818 | if (m == 0 && n == 0) { |
Jeremy Hylton | 0625777 | 2000-08-31 15:10:24 +0000 | [diff] [blame] | 819 | PySys_WriteStderr("gc: done.\n"); |
Neil Schemenauer | 544de1e | 2000-09-22 15:22:38 +0000 | [diff] [blame] | 820 | } |
| 821 | else { |
Jeremy Hylton | 0625777 | 2000-08-31 15:10:24 +0000 | [diff] [blame] | 822 | PySys_WriteStderr( |
| 823 | "gc: done, %ld unreachable, %ld uncollectable.\n", |
| 824 | n+m, n); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 825 | } |
| 826 | } |
| 827 | |
| 828 | /* Append instances in the uncollectable set to a Python |
| 829 | * reachable list of garbage. The programmer has to deal with |
Tim Peters | bf384c2 | 2003-04-06 00:11:39 +0000 | [diff] [blame] | 830 | * this if they insist on creating this type of structure. |
| 831 | */ |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 832 | (void)handle_finalizers(&finalizers, old); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 833 | |
Jeremy Hylton | b709df3 | 2000-09-01 02:47:25 +0000 | [diff] [blame] | 834 | if (PyErr_Occurred()) { |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 835 | if (gc_str == NULL) |
Tim Peters | fb2ab4d | 2003-04-07 22:41:24 +0000 | [diff] [blame] | 836 | gc_str = PyString_FromString("garbage collection"); |
Jeremy Hylton | b709df3 | 2000-09-01 02:47:25 +0000 | [diff] [blame] | 837 | PyErr_WriteUnraisable(gc_str); |
| 838 | Py_FatalError("unexpected exception during garbage collection"); |
| 839 | } |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 840 | return n+m; |
| 841 | } |
| 842 | |
| 843 | static long |
| 844 | collect_generations(void) |
| 845 | { |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 846 | int i; |
Vladimir Marangozov | b16714b | 2000-07-10 05:37:39 +0000 | [diff] [blame] | 847 | long n = 0; |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 848 | |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 849 | /* Find the oldest generation (higest numbered) where the count |
| 850 | * exceeds the threshold. Objects in the that generation and |
| 851 | * generations younger than it will be collected. */ |
| 852 | for (i = NUM_GENERATIONS-1; i >= 0; i--) { |
| 853 | if (generations[i].count > generations[i].threshold) { |
| 854 | n = collect(i); |
| 855 | break; |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 856 | } |
| 857 | } |
| 858 | return n; |
| 859 | } |
| 860 | |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 861 | PyDoc_STRVAR(gc_enable__doc__, |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 862 | "enable() -> None\n" |
| 863 | "\n" |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 864 | "Enable automatic garbage collection.\n"); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 865 | |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 866 | static PyObject * |
Tim Peters | 50c61d5 | 2003-04-06 01:50:50 +0000 | [diff] [blame] | 867 | gc_enable(PyObject *self, PyObject *noargs) |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 868 | { |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 869 | enabled = 1; |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 870 | Py_INCREF(Py_None); |
| 871 | return Py_None; |
| 872 | } |
| 873 | |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 874 | PyDoc_STRVAR(gc_disable__doc__, |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 875 | "disable() -> None\n" |
| 876 | "\n" |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 877 | "Disable automatic garbage collection.\n"); |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 878 | |
| 879 | static PyObject * |
Tim Peters | 50c61d5 | 2003-04-06 01:50:50 +0000 | [diff] [blame] | 880 | gc_disable(PyObject *self, PyObject *noargs) |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 881 | { |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 882 | enabled = 0; |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 883 | Py_INCREF(Py_None); |
| 884 | return Py_None; |
| 885 | } |
| 886 | |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 887 | PyDoc_STRVAR(gc_isenabled__doc__, |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 888 | "isenabled() -> status\n" |
| 889 | "\n" |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 890 | "Returns true if automatic garbage collection is enabled.\n"); |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 891 | |
| 892 | static PyObject * |
Tim Peters | 50c61d5 | 2003-04-06 01:50:50 +0000 | [diff] [blame] | 893 | gc_isenabled(PyObject *self, PyObject *noargs) |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 894 | { |
Raymond Hettinger | 674d56b | 2004-01-04 04:00:13 +0000 | [diff] [blame] | 895 | return PyBool_FromLong((long)enabled); |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 896 | } |
| 897 | |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 898 | PyDoc_STRVAR(gc_collect__doc__, |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 899 | "collect() -> n\n" |
| 900 | "\n" |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 901 | "Run a full collection. The number of unreachable objects is returned.\n"); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 902 | |
| 903 | static PyObject * |
Tim Peters | 50c61d5 | 2003-04-06 01:50:50 +0000 | [diff] [blame] | 904 | gc_collect(PyObject *self, PyObject *noargs) |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 905 | { |
| 906 | long n; |
| 907 | |
Tim Peters | 50c61d5 | 2003-04-06 01:50:50 +0000 | [diff] [blame] | 908 | if (collecting) |
Neil Schemenauer | e8c40cb | 2001-10-31 23:09:35 +0000 | [diff] [blame] | 909 | n = 0; /* already collecting, don't do anything */ |
Neil Schemenauer | e8c40cb | 2001-10-31 23:09:35 +0000 | [diff] [blame] | 910 | else { |
| 911 | collecting = 1; |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 912 | n = collect(NUM_GENERATIONS - 1); |
Neil Schemenauer | e8c40cb | 2001-10-31 23:09:35 +0000 | [diff] [blame] | 913 | collecting = 0; |
| 914 | } |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 915 | |
Neil Schemenauer | 7760cff | 2000-09-22 22:35:36 +0000 | [diff] [blame] | 916 | return Py_BuildValue("l", n); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 917 | } |
| 918 | |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 919 | PyDoc_STRVAR(gc_set_debug__doc__, |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 920 | "set_debug(flags) -> None\n" |
| 921 | "\n" |
| 922 | "Set the garbage collection debugging flags. Debugging information is\n" |
| 923 | "written to sys.stderr.\n" |
| 924 | "\n" |
| 925 | "flags is an integer and can have the following bits turned on:\n" |
| 926 | "\n" |
| 927 | " DEBUG_STATS - Print statistics during collection.\n" |
| 928 | " DEBUG_COLLECTABLE - Print collectable objects found.\n" |
| 929 | " DEBUG_UNCOLLECTABLE - Print unreachable but uncollectable objects found.\n" |
| 930 | " DEBUG_INSTANCES - Print instance objects.\n" |
| 931 | " DEBUG_OBJECTS - Print objects other than instances.\n" |
Neil Schemenauer | 544de1e | 2000-09-22 15:22:38 +0000 | [diff] [blame] | 932 | " DEBUG_SAVEALL - Save objects to gc.garbage rather than freeing them.\n" |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 933 | " DEBUG_LEAK - Debug leaking programs (everything but STATS).\n"); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 934 | |
| 935 | static PyObject * |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 936 | gc_set_debug(PyObject *self, PyObject *args) |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 937 | { |
Neil Schemenauer | 7760cff | 2000-09-22 22:35:36 +0000 | [diff] [blame] | 938 | if (!PyArg_ParseTuple(args, "i:set_debug", &debug)) |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 939 | return NULL; |
| 940 | |
| 941 | Py_INCREF(Py_None); |
| 942 | return Py_None; |
| 943 | } |
| 944 | |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 945 | PyDoc_STRVAR(gc_get_debug__doc__, |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 946 | "get_debug() -> flags\n" |
| 947 | "\n" |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 948 | "Get the garbage collection debugging flags.\n"); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 949 | |
| 950 | static PyObject * |
Tim Peters | 50c61d5 | 2003-04-06 01:50:50 +0000 | [diff] [blame] | 951 | gc_get_debug(PyObject *self, PyObject *noargs) |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 952 | { |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 953 | return Py_BuildValue("i", debug); |
| 954 | } |
| 955 | |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 956 | PyDoc_STRVAR(gc_set_thresh__doc__, |
Neal Norwitz | 2a47c0f | 2002-01-29 00:53:41 +0000 | [diff] [blame] | 957 | "set_threshold(threshold0, [threshold1, threshold2]) -> None\n" |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 958 | "\n" |
| 959 | "Sets the collection thresholds. Setting threshold0 to zero disables\n" |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 960 | "collection.\n"); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 961 | |
| 962 | static PyObject * |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 963 | gc_set_thresh(PyObject *self, PyObject *args) |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 964 | { |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 965 | int i; |
| 966 | if (!PyArg_ParseTuple(args, "i|ii:set_threshold", |
| 967 | &generations[0].threshold, |
| 968 | &generations[1].threshold, |
| 969 | &generations[2].threshold)) |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 970 | return NULL; |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 971 | for (i = 2; i < NUM_GENERATIONS; i++) { |
| 972 | /* generations higher than 2 get the same threshold */ |
| 973 | generations[i].threshold = generations[2].threshold; |
| 974 | } |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 975 | |
| 976 | Py_INCREF(Py_None); |
| 977 | return Py_None; |
| 978 | } |
| 979 | |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 980 | PyDoc_STRVAR(gc_get_thresh__doc__, |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 981 | "get_threshold() -> (threshold0, threshold1, threshold2)\n" |
| 982 | "\n" |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 983 | "Return the current collection thresholds\n"); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 984 | |
| 985 | static PyObject * |
Tim Peters | 50c61d5 | 2003-04-06 01:50:50 +0000 | [diff] [blame] | 986 | gc_get_thresh(PyObject *self, PyObject *noargs) |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 987 | { |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 988 | return Py_BuildValue("(iii)", |
| 989 | generations[0].threshold, |
| 990 | generations[1].threshold, |
| 991 | generations[2].threshold); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 992 | } |
| 993 | |
Neil Schemenauer | 48c7034 | 2001-08-09 15:38:31 +0000 | [diff] [blame] | 994 | static int |
Martin v. Löwis | 560da62 | 2001-11-24 09:24:51 +0000 | [diff] [blame] | 995 | referrersvisit(PyObject* obj, PyObject *objs) |
Neil Schemenauer | 48c7034 | 2001-08-09 15:38:31 +0000 | [diff] [blame] | 996 | { |
Martin v. Löwis | c8fe77b | 2001-11-29 18:08:31 +0000 | [diff] [blame] | 997 | int i; |
| 998 | for (i = 0; i < PyTuple_GET_SIZE(objs); i++) |
| 999 | if (PyTuple_GET_ITEM(objs, i) == obj) |
| 1000 | return 1; |
Neil Schemenauer | 48c7034 | 2001-08-09 15:38:31 +0000 | [diff] [blame] | 1001 | return 0; |
| 1002 | } |
| 1003 | |
Neil Schemenauer | 17e7be6 | 2001-08-10 14:46:47 +0000 | [diff] [blame] | 1004 | static int |
Martin v. Löwis | 560da62 | 2001-11-24 09:24:51 +0000 | [diff] [blame] | 1005 | gc_referrers_for(PyObject *objs, PyGC_Head *list, PyObject *resultlist) |
Neil Schemenauer | 48c7034 | 2001-08-09 15:38:31 +0000 | [diff] [blame] | 1006 | { |
| 1007 | PyGC_Head *gc; |
| 1008 | PyObject *obj; |
| 1009 | traverseproc traverse; |
Tim Peters | 9e4ca10 | 2001-10-11 18:31:31 +0000 | [diff] [blame] | 1010 | for (gc = list->gc.gc_next; gc != list; gc = gc->gc.gc_next) { |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1011 | obj = FROM_GC(gc); |
Neil Schemenauer | 48c7034 | 2001-08-09 15:38:31 +0000 | [diff] [blame] | 1012 | traverse = obj->ob_type->tp_traverse; |
| 1013 | if (obj == objs || obj == resultlist) |
| 1014 | continue; |
Martin v. Löwis | 560da62 | 2001-11-24 09:24:51 +0000 | [diff] [blame] | 1015 | if (traverse(obj, (visitproc)referrersvisit, objs)) { |
Neil Schemenauer | 17e7be6 | 2001-08-10 14:46:47 +0000 | [diff] [blame] | 1016 | if (PyList_Append(resultlist, obj) < 0) |
| 1017 | return 0; /* error */ |
Neil Schemenauer | 48c7034 | 2001-08-09 15:38:31 +0000 | [diff] [blame] | 1018 | } |
| 1019 | } |
Neil Schemenauer | 17e7be6 | 2001-08-10 14:46:47 +0000 | [diff] [blame] | 1020 | return 1; /* no error */ |
Neil Schemenauer | 48c7034 | 2001-08-09 15:38:31 +0000 | [diff] [blame] | 1021 | } |
| 1022 | |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 1023 | PyDoc_STRVAR(gc_get_referrers__doc__, |
Martin v. Löwis | 560da62 | 2001-11-24 09:24:51 +0000 | [diff] [blame] | 1024 | "get_referrers(*objs) -> list\n\ |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 1025 | Return the list of objects that directly refer to any of objs."); |
Neil Schemenauer | 48c7034 | 2001-08-09 15:38:31 +0000 | [diff] [blame] | 1026 | |
Neil Schemenauer | 17e7be6 | 2001-08-10 14:46:47 +0000 | [diff] [blame] | 1027 | static PyObject * |
Martin v. Löwis | 560da62 | 2001-11-24 09:24:51 +0000 | [diff] [blame] | 1028 | gc_get_referrers(PyObject *self, PyObject *args) |
Neil Schemenauer | 48c7034 | 2001-08-09 15:38:31 +0000 | [diff] [blame] | 1029 | { |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 1030 | int i; |
Neil Schemenauer | 48c7034 | 2001-08-09 15:38:31 +0000 | [diff] [blame] | 1031 | PyObject *result = PyList_New(0); |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 1032 | for (i = 0; i < NUM_GENERATIONS; i++) { |
| 1033 | if (!(gc_referrers_for(args, GEN_HEAD(i), result))) { |
| 1034 | Py_DECREF(result); |
| 1035 | return NULL; |
| 1036 | } |
Neil Schemenauer | 17e7be6 | 2001-08-10 14:46:47 +0000 | [diff] [blame] | 1037 | } |
Neil Schemenauer | 48c7034 | 2001-08-09 15:38:31 +0000 | [diff] [blame] | 1038 | return result; |
| 1039 | } |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 1040 | |
Tim Peters | 0f81ab6 | 2003-04-08 16:39:48 +0000 | [diff] [blame] | 1041 | /* Append obj to list; return true if error (out of memory), false if OK. */ |
Jeremy Hylton | 5bd378b | 2003-04-03 16:28:38 +0000 | [diff] [blame] | 1042 | static int |
Tim Peters | 730f553 | 2003-04-08 17:17:17 +0000 | [diff] [blame] | 1043 | referentsvisit(PyObject *obj, PyObject *list) |
Jeremy Hylton | 5bd378b | 2003-04-03 16:28:38 +0000 | [diff] [blame] | 1044 | { |
Tim Peters | 0f81ab6 | 2003-04-08 16:39:48 +0000 | [diff] [blame] | 1045 | return PyList_Append(list, obj) < 0; |
Jeremy Hylton | 5bd378b | 2003-04-03 16:28:38 +0000 | [diff] [blame] | 1046 | } |
| 1047 | |
Tim Peters | 730f553 | 2003-04-08 17:17:17 +0000 | [diff] [blame] | 1048 | PyDoc_STRVAR(gc_get_referents__doc__, |
| 1049 | "get_referents(*objs) -> list\n\ |
Jeremy Hylton | 059b094 | 2003-04-03 16:29:13 +0000 | [diff] [blame] | 1050 | Return the list of objects that are directly referred to by objs."); |
Jeremy Hylton | 5bd378b | 2003-04-03 16:28:38 +0000 | [diff] [blame] | 1051 | |
| 1052 | static PyObject * |
Tim Peters | 730f553 | 2003-04-08 17:17:17 +0000 | [diff] [blame] | 1053 | gc_get_referents(PyObject *self, PyObject *args) |
Jeremy Hylton | 5bd378b | 2003-04-03 16:28:38 +0000 | [diff] [blame] | 1054 | { |
| 1055 | int i; |
| 1056 | PyObject *result = PyList_New(0); |
Tim Peters | 0f81ab6 | 2003-04-08 16:39:48 +0000 | [diff] [blame] | 1057 | |
| 1058 | if (result == NULL) |
| 1059 | return NULL; |
| 1060 | |
Jeremy Hylton | 5bd378b | 2003-04-03 16:28:38 +0000 | [diff] [blame] | 1061 | for (i = 0; i < PyTuple_GET_SIZE(args); i++) { |
Tim Peters | 0f81ab6 | 2003-04-08 16:39:48 +0000 | [diff] [blame] | 1062 | traverseproc traverse; |
Tim Peters | 93ad66d | 2003-04-05 17:15:44 +0000 | [diff] [blame] | 1063 | PyObject *obj = PyTuple_GET_ITEM(args, i); |
Tim Peters | 0f81ab6 | 2003-04-08 16:39:48 +0000 | [diff] [blame] | 1064 | |
| 1065 | if (! PyObject_IS_GC(obj)) |
Jeremy Hylton | 5bd378b | 2003-04-03 16:28:38 +0000 | [diff] [blame] | 1066 | continue; |
Tim Peters | 0f81ab6 | 2003-04-08 16:39:48 +0000 | [diff] [blame] | 1067 | traverse = obj->ob_type->tp_traverse; |
| 1068 | if (! traverse) |
| 1069 | continue; |
Tim Peters | 730f553 | 2003-04-08 17:17:17 +0000 | [diff] [blame] | 1070 | if (traverse(obj, (visitproc)referentsvisit, result)) { |
Tim Peters | 0f81ab6 | 2003-04-08 16:39:48 +0000 | [diff] [blame] | 1071 | Py_DECREF(result); |
Jeremy Hylton | 5bd378b | 2003-04-03 16:28:38 +0000 | [diff] [blame] | 1072 | return NULL; |
Tim Peters | 0f81ab6 | 2003-04-08 16:39:48 +0000 | [diff] [blame] | 1073 | } |
Jeremy Hylton | 5bd378b | 2003-04-03 16:28:38 +0000 | [diff] [blame] | 1074 | } |
| 1075 | return result; |
| 1076 | } |
| 1077 | |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 1078 | PyDoc_STRVAR(gc_get_objects__doc__, |
Neil Schemenauer | c7c8d8e | 2001-08-09 15:58:59 +0000 | [diff] [blame] | 1079 | "get_objects() -> [...]\n" |
| 1080 | "\n" |
| 1081 | "Return a list of objects tracked by the collector (excluding the list\n" |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 1082 | "returned).\n"); |
Neil Schemenauer | c7c8d8e | 2001-08-09 15:58:59 +0000 | [diff] [blame] | 1083 | |
Neil Schemenauer | c7c8d8e | 2001-08-09 15:58:59 +0000 | [diff] [blame] | 1084 | static PyObject * |
Tim Peters | 50c61d5 | 2003-04-06 01:50:50 +0000 | [diff] [blame] | 1085 | gc_get_objects(PyObject *self, PyObject *noargs) |
Neil Schemenauer | c7c8d8e | 2001-08-09 15:58:59 +0000 | [diff] [blame] | 1086 | { |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 1087 | int i; |
Neil Schemenauer | c7c8d8e | 2001-08-09 15:58:59 +0000 | [diff] [blame] | 1088 | PyObject* result; |
| 1089 | |
Neil Schemenauer | c7c8d8e | 2001-08-09 15:58:59 +0000 | [diff] [blame] | 1090 | result = PyList_New(0); |
Tim Peters | 50c61d5 | 2003-04-06 01:50:50 +0000 | [diff] [blame] | 1091 | if (result == NULL) |
Martin v. Löwis | f8a6f24 | 2001-12-02 18:31:02 +0000 | [diff] [blame] | 1092 | return NULL; |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 1093 | for (i = 0; i < NUM_GENERATIONS; i++) { |
| 1094 | if (append_objects(result, GEN_HEAD(i))) { |
| 1095 | Py_DECREF(result); |
| 1096 | return NULL; |
| 1097 | } |
Martin v. Löwis | 155aad1 | 2001-12-02 12:21:34 +0000 | [diff] [blame] | 1098 | } |
Neil Schemenauer | c7c8d8e | 2001-08-09 15:58:59 +0000 | [diff] [blame] | 1099 | return result; |
| 1100 | } |
| 1101 | |
| 1102 | |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 1103 | PyDoc_STRVAR(gc__doc__, |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 1104 | "This module provides access to the garbage collector for reference cycles.\n" |
| 1105 | "\n" |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 1106 | "enable() -- Enable automatic garbage collection.\n" |
| 1107 | "disable() -- Disable automatic garbage collection.\n" |
| 1108 | "isenabled() -- Returns true if automatic collection is enabled.\n" |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 1109 | "collect() -- Do a full collection right now.\n" |
| 1110 | "set_debug() -- Set debugging flags.\n" |
| 1111 | "get_debug() -- Get debugging flags.\n" |
| 1112 | "set_threshold() -- Set the collection thresholds.\n" |
| 1113 | "get_threshold() -- Return the current the collection thresholds.\n" |
Neil Schemenauer | c7c8d8e | 2001-08-09 15:58:59 +0000 | [diff] [blame] | 1114 | "get_objects() -- Return a list of all objects tracked by the collector.\n" |
Jeremy Hylton | 5bd378b | 2003-04-03 16:28:38 +0000 | [diff] [blame] | 1115 | "get_referrers() -- Return the list of objects that refer to an object.\n" |
Tim Peters | 730f553 | 2003-04-08 17:17:17 +0000 | [diff] [blame] | 1116 | "get_referents() -- Return the list of objects that an object refers to.\n"); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 1117 | |
| 1118 | static PyMethodDef GcMethods[] = { |
Tim Peters | 50c61d5 | 2003-04-06 01:50:50 +0000 | [diff] [blame] | 1119 | {"enable", gc_enable, METH_NOARGS, gc_enable__doc__}, |
| 1120 | {"disable", gc_disable, METH_NOARGS, gc_disable__doc__}, |
| 1121 | {"isenabled", gc_isenabled, METH_NOARGS, gc_isenabled__doc__}, |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 1122 | {"set_debug", gc_set_debug, METH_VARARGS, gc_set_debug__doc__}, |
Tim Peters | 50c61d5 | 2003-04-06 01:50:50 +0000 | [diff] [blame] | 1123 | {"get_debug", gc_get_debug, METH_NOARGS, gc_get_debug__doc__}, |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 1124 | {"set_threshold", gc_set_thresh, METH_VARARGS, gc_set_thresh__doc__}, |
Tim Peters | 50c61d5 | 2003-04-06 01:50:50 +0000 | [diff] [blame] | 1125 | {"get_threshold", gc_get_thresh, METH_NOARGS, gc_get_thresh__doc__}, |
| 1126 | {"collect", gc_collect, METH_NOARGS, gc_collect__doc__}, |
| 1127 | {"get_objects", gc_get_objects,METH_NOARGS, gc_get_objects__doc__}, |
Martin v. Löwis | 560da62 | 2001-11-24 09:24:51 +0000 | [diff] [blame] | 1128 | {"get_referrers", gc_get_referrers, METH_VARARGS, |
| 1129 | gc_get_referrers__doc__}, |
Tim Peters | 730f553 | 2003-04-08 17:17:17 +0000 | [diff] [blame] | 1130 | {"get_referents", gc_get_referents, METH_VARARGS, |
| 1131 | gc_get_referents__doc__}, |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 1132 | {NULL, NULL} /* Sentinel */ |
| 1133 | }; |
| 1134 | |
Jason Tishler | 6bc06ec | 2003-09-04 11:59:50 +0000 | [diff] [blame] | 1135 | PyMODINIT_FUNC |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 1136 | initgc(void) |
| 1137 | { |
| 1138 | PyObject *m; |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 1139 | |
| 1140 | m = Py_InitModule4("gc", |
| 1141 | GcMethods, |
| 1142 | gc__doc__, |
| 1143 | NULL, |
| 1144 | PYTHON_API_VERSION); |
Tim Peters | 1155887 | 2003-04-06 23:30:52 +0000 | [diff] [blame] | 1145 | |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 1146 | if (garbage == NULL) { |
| 1147 | garbage = PyList_New(0); |
Tim Peters | 1155887 | 2003-04-06 23:30:52 +0000 | [diff] [blame] | 1148 | if (garbage == NULL) |
| 1149 | return; |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 1150 | } |
Tim Peters | 1155887 | 2003-04-06 23:30:52 +0000 | [diff] [blame] | 1151 | if (PyModule_AddObject(m, "garbage", garbage) < 0) |
| 1152 | return; |
| 1153 | #define ADD_INT(NAME) if (PyModule_AddIntConstant(m, #NAME, NAME) < 0) return |
| 1154 | ADD_INT(DEBUG_STATS); |
| 1155 | ADD_INT(DEBUG_COLLECTABLE); |
| 1156 | ADD_INT(DEBUG_UNCOLLECTABLE); |
| 1157 | ADD_INT(DEBUG_INSTANCES); |
| 1158 | ADD_INT(DEBUG_OBJECTS); |
| 1159 | ADD_INT(DEBUG_SAVEALL); |
| 1160 | ADD_INT(DEBUG_LEAK); |
| 1161 | #undef ADD_INT |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 1162 | } |
| 1163 | |
Guido van Rossum | e13ddc9 | 2003-04-17 17:29:22 +0000 | [diff] [blame] | 1164 | /* API to invoke gc.collect() from C */ |
| 1165 | long |
| 1166 | PyGC_Collect(void) |
| 1167 | { |
| 1168 | long n; |
| 1169 | |
| 1170 | if (collecting) |
| 1171 | n = 0; /* already collecting, don't do anything */ |
| 1172 | else { |
| 1173 | collecting = 1; |
| 1174 | n = collect(NUM_GENERATIONS - 1); |
| 1175 | collecting = 0; |
| 1176 | } |
| 1177 | |
| 1178 | return n; |
| 1179 | } |
| 1180 | |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1181 | /* for debugging */ |
Guido van Rossum | e13ddc9 | 2003-04-17 17:29:22 +0000 | [diff] [blame] | 1182 | void |
| 1183 | _PyGC_Dump(PyGC_Head *g) |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1184 | { |
| 1185 | _PyObject_Dump(FROM_GC(g)); |
| 1186 | } |
| 1187 | |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1188 | /* extension modules might be compiled with GC support so these |
| 1189 | functions must always be available */ |
| 1190 | |
Neil Schemenauer | fec4eb1 | 2002-04-12 02:41:03 +0000 | [diff] [blame] | 1191 | #undef PyObject_GC_Track |
| 1192 | #undef PyObject_GC_UnTrack |
| 1193 | #undef PyObject_GC_Del |
| 1194 | #undef _PyObject_GC_Malloc |
| 1195 | |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1196 | void |
Neil Schemenauer | fec4eb1 | 2002-04-12 02:41:03 +0000 | [diff] [blame] | 1197 | PyObject_GC_Track(void *op) |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1198 | { |
| 1199 | _PyObject_GC_TRACK(op); |
| 1200 | } |
| 1201 | |
Neil Schemenauer | fec4eb1 | 2002-04-12 02:41:03 +0000 | [diff] [blame] | 1202 | /* for binary compatibility with 2.2 */ |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1203 | void |
Neil Schemenauer | fec4eb1 | 2002-04-12 02:41:03 +0000 | [diff] [blame] | 1204 | _PyObject_GC_Track(PyObject *op) |
| 1205 | { |
| 1206 | PyObject_GC_Track(op); |
| 1207 | } |
| 1208 | |
| 1209 | void |
| 1210 | PyObject_GC_UnTrack(void *op) |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1211 | { |
Tim Peters | 803526b | 2002-07-07 05:13:56 +0000 | [diff] [blame] | 1212 | /* Obscure: the Py_TRASHCAN mechanism requires that we be able to |
| 1213 | * call PyObject_GC_UnTrack twice on an object. |
| 1214 | */ |
Neil Schemenauer | a2b11ec | 2002-05-21 15:53:24 +0000 | [diff] [blame] | 1215 | if (IS_TRACKED(op)) |
Guido van Rossum | ff413af | 2002-03-28 20:34:59 +0000 | [diff] [blame] | 1216 | _PyObject_GC_UNTRACK(op); |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1217 | } |
| 1218 | |
Neil Schemenauer | fec4eb1 | 2002-04-12 02:41:03 +0000 | [diff] [blame] | 1219 | /* for binary compatibility with 2.2 */ |
| 1220 | void |
| 1221 | _PyObject_GC_UnTrack(PyObject *op) |
| 1222 | { |
| 1223 | PyObject_GC_UnTrack(op); |
| 1224 | } |
| 1225 | |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1226 | PyObject * |
Neil Schemenauer | fec4eb1 | 2002-04-12 02:41:03 +0000 | [diff] [blame] | 1227 | _PyObject_GC_Malloc(size_t basicsize) |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1228 | { |
| 1229 | PyObject *op; |
Neil Schemenauer | fec4eb1 | 2002-04-12 02:41:03 +0000 | [diff] [blame] | 1230 | PyGC_Head *g = PyObject_MALLOC(sizeof(PyGC_Head) + basicsize); |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1231 | if (g == NULL) |
Jeremy Hylton | 8a13518 | 2002-06-06 23:23:55 +0000 | [diff] [blame] | 1232 | return PyErr_NoMemory(); |
Tim Peters | ea40563 | 2002-07-02 00:52:30 +0000 | [diff] [blame] | 1233 | g->gc.gc_refs = GC_UNTRACKED; |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 1234 | generations[0].count++; /* number of allocated GC objects */ |
| 1235 | if (generations[0].count > generations[0].threshold && |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1236 | enabled && |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 1237 | generations[0].threshold && |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1238 | !collecting && |
| 1239 | !PyErr_Occurred()) { |
| 1240 | collecting = 1; |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 1241 | collect_generations(); |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1242 | collecting = 0; |
| 1243 | } |
| 1244 | op = FROM_GC(g); |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1245 | return op; |
| 1246 | } |
| 1247 | |
| 1248 | PyObject * |
| 1249 | _PyObject_GC_New(PyTypeObject *tp) |
| 1250 | { |
Neil Schemenauer | fec4eb1 | 2002-04-12 02:41:03 +0000 | [diff] [blame] | 1251 | PyObject *op = _PyObject_GC_Malloc(_PyObject_SIZE(tp)); |
Tim Peters | fa8efab | 2002-04-28 01:57:25 +0000 | [diff] [blame] | 1252 | if (op != NULL) |
| 1253 | op = PyObject_INIT(op, tp); |
| 1254 | return op; |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1255 | } |
| 1256 | |
| 1257 | PyVarObject * |
Tim Peters | 6d483d3 | 2001-10-06 21:27:34 +0000 | [diff] [blame] | 1258 | _PyObject_GC_NewVar(PyTypeObject *tp, int nitems) |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1259 | { |
Neil Schemenauer | fec4eb1 | 2002-04-12 02:41:03 +0000 | [diff] [blame] | 1260 | const size_t size = _PyObject_VAR_SIZE(tp, nitems); |
| 1261 | PyVarObject *op = (PyVarObject *) _PyObject_GC_Malloc(size); |
Tim Peters | fa8efab | 2002-04-28 01:57:25 +0000 | [diff] [blame] | 1262 | if (op != NULL) |
| 1263 | op = PyObject_INIT_VAR(op, tp, nitems); |
| 1264 | return op; |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1265 | } |
| 1266 | |
| 1267 | PyVarObject * |
Tim Peters | 6d483d3 | 2001-10-06 21:27:34 +0000 | [diff] [blame] | 1268 | _PyObject_GC_Resize(PyVarObject *op, int nitems) |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1269 | { |
Tim Peters | f2a67da | 2001-10-07 03:54:51 +0000 | [diff] [blame] | 1270 | const size_t basicsize = _PyObject_VAR_SIZE(op->ob_type, nitems); |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1271 | PyGC_Head *g = AS_GC(op); |
Neil Schemenauer | fec4eb1 | 2002-04-12 02:41:03 +0000 | [diff] [blame] | 1272 | g = PyObject_REALLOC(g, sizeof(PyGC_Head) + basicsize); |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1273 | if (g == NULL) |
| 1274 | return (PyVarObject *)PyErr_NoMemory(); |
| 1275 | op = (PyVarObject *) FROM_GC(g); |
Tim Peters | 6d483d3 | 2001-10-06 21:27:34 +0000 | [diff] [blame] | 1276 | op->ob_size = nitems; |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1277 | return op; |
| 1278 | } |
| 1279 | |
| 1280 | void |
Neil Schemenauer | fec4eb1 | 2002-04-12 02:41:03 +0000 | [diff] [blame] | 1281 | PyObject_GC_Del(void *op) |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1282 | { |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1283 | PyGC_Head *g = AS_GC(op); |
Neil Schemenauer | a2b11ec | 2002-05-21 15:53:24 +0000 | [diff] [blame] | 1284 | if (IS_TRACKED(op)) |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1285 | gc_list_remove(g); |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 1286 | if (generations[0].count > 0) { |
| 1287 | generations[0].count--; |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1288 | } |
Neil Schemenauer | fec4eb1 | 2002-04-12 02:41:03 +0000 | [diff] [blame] | 1289 | PyObject_FREE(g); |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1290 | } |
| 1291 | |
Neil Schemenauer | fec4eb1 | 2002-04-12 02:41:03 +0000 | [diff] [blame] | 1292 | /* for binary compatibility with 2.2 */ |
| 1293 | #undef _PyObject_GC_Del |
| 1294 | void |
| 1295 | _PyObject_GC_Del(PyObject *op) |
| 1296 | { |
| 1297 | PyObject_GC_Del(op); |
| 1298 | } |