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 | |
Tim Peters | e2d5918 | 2004-11-01 01:39:08 +0000 | [diff] [blame] | 142 | #if 0 |
| 143 | /* This became unused after gc_list_move() was introduced. */ |
| 144 | /* Append `node` to `list`. */ |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 145 | static void |
| 146 | gc_list_append(PyGC_Head *node, PyGC_Head *list) |
| 147 | { |
Tim Peters | 9e4ca10 | 2001-10-11 18:31:31 +0000 | [diff] [blame] | 148 | node->gc.gc_next = list; |
| 149 | node->gc.gc_prev = list->gc.gc_prev; |
| 150 | node->gc.gc_prev->gc.gc_next = node; |
| 151 | list->gc.gc_prev = node; |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 152 | } |
Tim Peters | e2d5918 | 2004-11-01 01:39:08 +0000 | [diff] [blame] | 153 | #endif |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 154 | |
Tim Peters | e2d5918 | 2004-11-01 01:39:08 +0000 | [diff] [blame] | 155 | /* Remove `node` from the gc list it's currently in. */ |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 156 | static void |
| 157 | gc_list_remove(PyGC_Head *node) |
| 158 | { |
Tim Peters | 9e4ca10 | 2001-10-11 18:31:31 +0000 | [diff] [blame] | 159 | node->gc.gc_prev->gc.gc_next = node->gc.gc_next; |
| 160 | node->gc.gc_next->gc.gc_prev = node->gc.gc_prev; |
| 161 | node->gc.gc_next = NULL; /* object is not currently tracked */ |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 162 | } |
| 163 | |
Tim Peters | e2d5918 | 2004-11-01 01:39:08 +0000 | [diff] [blame] | 164 | /* Move `node` from the gc list it's currently in (which is not explicitly |
| 165 | * named here) to the end of `list`. This is semantically the same as |
| 166 | * gc_list_remove(node) followed by gc_list_append(node, list). |
| 167 | */ |
| 168 | static void |
| 169 | gc_list_move(PyGC_Head *node, PyGC_Head *list) |
| 170 | { |
Tim Peters | bc1d1b8 | 2004-11-01 16:39:57 +0000 | [diff] [blame] | 171 | PyGC_Head *new_prev; |
Tim Peters | e2d5918 | 2004-11-01 01:39:08 +0000 | [diff] [blame] | 172 | PyGC_Head *current_prev = node->gc.gc_prev; |
| 173 | PyGC_Head *current_next = node->gc.gc_next; |
Tim Peters | bc1d1b8 | 2004-11-01 16:39:57 +0000 | [diff] [blame] | 174 | /* Unlink from current list. */ |
Tim Peters | e2d5918 | 2004-11-01 01:39:08 +0000 | [diff] [blame] | 175 | current_prev->gc.gc_next = current_next; |
| 176 | current_next->gc.gc_prev = current_prev; |
Tim Peters | bc1d1b8 | 2004-11-01 16:39:57 +0000 | [diff] [blame] | 177 | /* Relink at end of new list. */ |
| 178 | new_prev = node->gc.gc_prev = list->gc.gc_prev; |
Tim Peters | e2d5918 | 2004-11-01 01:39:08 +0000 | [diff] [blame] | 179 | new_prev->gc.gc_next = list->gc.gc_prev = node; |
Tim Peters | bc1d1b8 | 2004-11-01 16:39:57 +0000 | [diff] [blame] | 180 | node->gc.gc_next = list; |
Tim Peters | e2d5918 | 2004-11-01 01:39:08 +0000 | [diff] [blame] | 181 | } |
| 182 | |
| 183 | /* append list `from` onto list `to`; `from` becomes an empty list */ |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 184 | static void |
| 185 | gc_list_merge(PyGC_Head *from, PyGC_Head *to) |
| 186 | { |
| 187 | PyGC_Head *tail; |
Tim Peters | e2d5918 | 2004-11-01 01:39:08 +0000 | [diff] [blame] | 188 | assert(from != to); |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 189 | if (!gc_list_is_empty(from)) { |
Tim Peters | 9e4ca10 | 2001-10-11 18:31:31 +0000 | [diff] [blame] | 190 | tail = to->gc.gc_prev; |
| 191 | tail->gc.gc_next = from->gc.gc_next; |
| 192 | tail->gc.gc_next->gc.gc_prev = tail; |
| 193 | to->gc.gc_prev = from->gc.gc_prev; |
| 194 | to->gc.gc_prev->gc.gc_next = to; |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 195 | } |
| 196 | gc_list_init(from); |
| 197 | } |
| 198 | |
| 199 | static long |
| 200 | gc_list_size(PyGC_Head *list) |
| 201 | { |
| 202 | PyGC_Head *gc; |
| 203 | long n = 0; |
Tim Peters | 9e4ca10 | 2001-10-11 18:31:31 +0000 | [diff] [blame] | 204 | 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] | 205 | n++; |
| 206 | } |
| 207 | return n; |
| 208 | } |
| 209 | |
Tim Peters | 259272b | 2003-04-06 19:41:39 +0000 | [diff] [blame] | 210 | /* Append objects in a GC list to a Python list. |
| 211 | * Return 0 if all OK, < 0 if error (out of memory for list). |
| 212 | */ |
| 213 | static int |
| 214 | append_objects(PyObject *py_list, PyGC_Head *gc_list) |
| 215 | { |
| 216 | PyGC_Head *gc; |
| 217 | for (gc = gc_list->gc.gc_next; gc != gc_list; gc = gc->gc.gc_next) { |
| 218 | PyObject *op = FROM_GC(gc); |
| 219 | if (op != py_list) { |
| 220 | if (PyList_Append(py_list, op)) { |
| 221 | return -1; /* exception */ |
| 222 | } |
| 223 | } |
| 224 | } |
| 225 | return 0; |
| 226 | } |
| 227 | |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 228 | /*** end of list stuff ***/ |
| 229 | |
| 230 | |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 231 | /* Set all gc_refs = ob_refcnt. After this, gc_refs is > 0 for all objects |
| 232 | * in containers, and is GC_REACHABLE for all tracked gc objects not in |
| 233 | * containers. |
Tim Peters | 8839617 | 2002-06-30 17:56:40 +0000 | [diff] [blame] | 234 | */ |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 235 | static void |
| 236 | update_refs(PyGC_Head *containers) |
| 237 | { |
Tim Peters | 9e4ca10 | 2001-10-11 18:31:31 +0000 | [diff] [blame] | 238 | PyGC_Head *gc = containers->gc.gc_next; |
Tim Peters | ea40563 | 2002-07-02 00:52:30 +0000 | [diff] [blame] | 239 | for (; gc != containers; gc = gc->gc.gc_next) { |
| 240 | assert(gc->gc.gc_refs == GC_REACHABLE); |
Tim Peters | 9e4ca10 | 2001-10-11 18:31:31 +0000 | [diff] [blame] | 241 | gc->gc.gc_refs = FROM_GC(gc)->ob_refcnt; |
Tim Peters | 780c497 | 2003-11-14 00:01:17 +0000 | [diff] [blame] | 242 | /* Python's cyclic gc should never see an incoming refcount |
| 243 | * of 0: if something decref'ed to 0, it should have been |
| 244 | * deallocated immediately at that time. |
| 245 | * Possible cause (if the assert triggers): a tp_dealloc |
| 246 | * routine left a gc-aware object tracked during its teardown |
| 247 | * phase, and did something-- or allowed something to happen -- |
| 248 | * that called back into Python. gc can trigger then, and may |
| 249 | * see the still-tracked dying object. Before this assert |
| 250 | * was added, such mistakes went on to allow gc to try to |
| 251 | * delete the object again. In a debug build, that caused |
| 252 | * a mysterious segfault, when _Py_ForgetReference tried |
| 253 | * to remove the object from the doubly-linked list of all |
| 254 | * objects a second time. In a release build, an actual |
| 255 | * double deallocation occurred, which leads to corruption |
| 256 | * of the allocator's internal bookkeeping pointers. That's |
| 257 | * so serious that maybe this should be a release-build |
| 258 | * check instead of an assert? |
| 259 | */ |
| 260 | assert(gc->gc.gc_refs != 0); |
Tim Peters | ea40563 | 2002-07-02 00:52:30 +0000 | [diff] [blame] | 261 | } |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 262 | } |
| 263 | |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 264 | /* A traversal callback for subtract_refs. */ |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 265 | static int |
| 266 | visit_decref(PyObject *op, void *data) |
| 267 | { |
Tim Peters | 93cd83e | 2002-06-30 21:31:03 +0000 | [diff] [blame] | 268 | assert(op != NULL); |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 269 | if (PyObject_IS_GC(op)) { |
| 270 | PyGC_Head *gc = AS_GC(op); |
| 271 | /* We're only interested in gc_refs for objects in the |
| 272 | * generation being collected, which can be recognized |
| 273 | * because only they have positive gc_refs. |
| 274 | */ |
Tim Peters | aab713b | 2002-07-02 22:15:28 +0000 | [diff] [blame] | 275 | assert(gc->gc.gc_refs != 0); /* else refcount was too small */ |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 276 | if (gc->gc.gc_refs > 0) |
| 277 | gc->gc.gc_refs--; |
| 278 | } |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 279 | return 0; |
| 280 | } |
| 281 | |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 282 | /* Subtract internal references from gc_refs. After this, gc_refs is >= 0 |
| 283 | * for all objects in containers, and is GC_REACHABLE for all tracked gc |
| 284 | * objects not in containers. The ones with gc_refs > 0 are directly |
| 285 | * reachable from outside containers, and so can't be collected. |
| 286 | */ |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 287 | static void |
| 288 | subtract_refs(PyGC_Head *containers) |
| 289 | { |
| 290 | traverseproc traverse; |
Tim Peters | 9e4ca10 | 2001-10-11 18:31:31 +0000 | [diff] [blame] | 291 | PyGC_Head *gc = containers->gc.gc_next; |
| 292 | for (; gc != containers; gc=gc->gc.gc_next) { |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 293 | traverse = FROM_GC(gc)->ob_type->tp_traverse; |
| 294 | (void) traverse(FROM_GC(gc), |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 295 | (visitproc)visit_decref, |
| 296 | NULL); |
| 297 | } |
| 298 | } |
| 299 | |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 300 | /* A traversal callback for move_unreachable. */ |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 301 | static int |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 302 | visit_reachable(PyObject *op, PyGC_Head *reachable) |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 303 | { |
Tim Peters | ea40563 | 2002-07-02 00:52:30 +0000 | [diff] [blame] | 304 | if (PyObject_IS_GC(op)) { |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 305 | PyGC_Head *gc = AS_GC(op); |
| 306 | const int gc_refs = gc->gc.gc_refs; |
| 307 | |
| 308 | if (gc_refs == 0) { |
| 309 | /* This is in move_unreachable's 'young' list, but |
| 310 | * the traversal hasn't yet gotten to it. All |
| 311 | * we need to do is tell move_unreachable that it's |
| 312 | * reachable. |
| 313 | */ |
| 314 | gc->gc.gc_refs = 1; |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 315 | } |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 316 | else if (gc_refs == GC_TENTATIVELY_UNREACHABLE) { |
| 317 | /* This had gc_refs = 0 when move_unreachable got |
| 318 | * to it, but turns out it's reachable after all. |
| 319 | * Move it back to move_unreachable's 'young' list, |
| 320 | * and move_unreachable will eventually get to it |
| 321 | * again. |
| 322 | */ |
Tim Peters | e2d5918 | 2004-11-01 01:39:08 +0000 | [diff] [blame] | 323 | gc_list_move(gc, reachable); |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 324 | gc->gc.gc_refs = 1; |
| 325 | } |
| 326 | /* Else there's nothing to do. |
| 327 | * If gc_refs > 0, it must be in move_unreachable's 'young' |
| 328 | * list, and move_unreachable will eventually get to it. |
| 329 | * If gc_refs == GC_REACHABLE, it's either in some other |
| 330 | * generation so we don't care about it, or move_unreachable |
Tim Peters | 6fc13d9 | 2002-07-02 18:12:35 +0000 | [diff] [blame] | 331 | * already dealt with it. |
Tim Peters | ea40563 | 2002-07-02 00:52:30 +0000 | [diff] [blame] | 332 | * If gc_refs == GC_UNTRACKED, it must be ignored. |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 333 | */ |
Tim Peters | ea40563 | 2002-07-02 00:52:30 +0000 | [diff] [blame] | 334 | else { |
| 335 | assert(gc_refs > 0 |
| 336 | || gc_refs == GC_REACHABLE |
| 337 | || gc_refs == GC_UNTRACKED); |
| 338 | } |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 339 | } |
| 340 | return 0; |
| 341 | } |
| 342 | |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 343 | /* Move the unreachable objects from young to unreachable. After this, |
| 344 | * all objects in young have gc_refs = GC_REACHABLE, and all objects in |
| 345 | * unreachable have gc_refs = GC_TENTATIVELY_UNREACHABLE. All tracked |
| 346 | * gc objects not in young or unreachable still have gc_refs = GC_REACHABLE. |
| 347 | * All objects in young after this are directly or indirectly reachable |
| 348 | * from outside the original young; and all objects in unreachable are |
| 349 | * not. |
Tim Peters | 8839617 | 2002-06-30 17:56:40 +0000 | [diff] [blame] | 350 | */ |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 351 | static void |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 352 | move_unreachable(PyGC_Head *young, PyGC_Head *unreachable) |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 353 | { |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 354 | PyGC_Head *gc = young->gc.gc_next; |
| 355 | |
| 356 | /* Invariants: all objects "to the left" of us in young have gc_refs |
| 357 | * = GC_REACHABLE, and are indeed reachable (directly or indirectly) |
| 358 | * from outside the young list as it was at entry. All other objects |
| 359 | * from the original young "to the left" of us are in unreachable now, |
| 360 | * and have gc_refs = GC_TENTATIVELY_UNREACHABLE. All objects to the |
| 361 | * left of us in 'young' now have been scanned, and no objects here |
| 362 | * or to the right have been scanned yet. |
| 363 | */ |
| 364 | |
| 365 | while (gc != young) { |
| 366 | PyGC_Head *next; |
| 367 | |
Tim Peters | 6fc13d9 | 2002-07-02 18:12:35 +0000 | [diff] [blame] | 368 | if (gc->gc.gc_refs) { |
| 369 | /* gc is definitely reachable from outside the |
| 370 | * original 'young'. Mark it as such, and traverse |
| 371 | * its pointers to find any other objects that may |
| 372 | * be directly reachable from it. Note that the |
| 373 | * call to tp_traverse may append objects to young, |
| 374 | * so we have to wait until it returns to determine |
| 375 | * the next object to visit. |
| 376 | */ |
| 377 | PyObject *op = FROM_GC(gc); |
| 378 | traverseproc traverse = op->ob_type->tp_traverse; |
| 379 | assert(gc->gc.gc_refs > 0); |
| 380 | gc->gc.gc_refs = GC_REACHABLE; |
| 381 | (void) traverse(op, |
| 382 | (visitproc)visit_reachable, |
| 383 | (void *)young); |
| 384 | next = gc->gc.gc_next; |
| 385 | } |
| 386 | else { |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 387 | /* This *may* be unreachable. To make progress, |
| 388 | * assume it is. gc isn't directly reachable from |
| 389 | * any object we've already traversed, but may be |
| 390 | * reachable from an object we haven't gotten to yet. |
| 391 | * visit_reachable will eventually move gc back into |
| 392 | * young if that's so, and we'll see it again. |
| 393 | */ |
| 394 | next = gc->gc.gc_next; |
Tim Peters | e2d5918 | 2004-11-01 01:39:08 +0000 | [diff] [blame] | 395 | gc_list_move(gc, unreachable); |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 396 | gc->gc.gc_refs = GC_TENTATIVELY_UNREACHABLE; |
| 397 | } |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 398 | gc = next; |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 399 | } |
| 400 | } |
| 401 | |
Tim Peters | 86b993b | 2003-04-05 17:35:54 +0000 | [diff] [blame] | 402 | /* Return true if object has a finalization method. |
| 403 | * 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] | 404 | *__del__ method, and earlier versions of this used to call PyObject_HasAttr, |
| 405 | * which in turn could call the class's __getattr__ hook (if any). That |
| 406 | * could invoke arbitrary Python code, mutating the object graph in arbitrary |
| 407 | * ways, and that was the source of some excruciatingly subtle bugs. |
Tim Peters | 86b993b | 2003-04-05 17:35:54 +0000 | [diff] [blame] | 408 | */ |
Neil Schemenauer | a765c12 | 2001-11-01 17:35:23 +0000 | [diff] [blame] | 409 | static int |
| 410 | has_finalizer(PyObject *op) |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 411 | { |
Tim Peters | 86b993b | 2003-04-05 17:35:54 +0000 | [diff] [blame] | 412 | if (PyInstance_Check(op)) { |
Tim Peters | 86b993b | 2003-04-05 17:35:54 +0000 | [diff] [blame] | 413 | assert(delstr != NULL); |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 414 | return _PyInstance_Lookup(op, delstr) != NULL; |
Tim Peters | 86b993b | 2003-04-05 17:35:54 +0000 | [diff] [blame] | 415 | } |
Phillip J. Eby | 0d6615f | 2005-08-02 00:46:46 +0000 | [diff] [blame] | 416 | else |
Tim Peters | 86b993b | 2003-04-05 17:35:54 +0000 | [diff] [blame] | 417 | return op->ob_type->tp_del != NULL; |
Neil Schemenauer | a765c12 | 2001-11-01 17:35:23 +0000 | [diff] [blame] | 418 | } |
| 419 | |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 420 | /* Move the objects in unreachable with __del__ methods into `finalizers`. |
| 421 | * Objects moved into `finalizers` have gc_refs set to GC_REACHABLE; the |
| 422 | * objects remaining in unreachable are left at GC_TENTATIVELY_UNREACHABLE. |
Jeremy Hylton | ce136e9 | 2003-04-04 19:59:06 +0000 | [diff] [blame] | 423 | */ |
Neil Schemenauer | a765c12 | 2001-11-01 17:35:23 +0000 | [diff] [blame] | 424 | static void |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 425 | move_finalizers(PyGC_Head *unreachable, PyGC_Head *finalizers) |
Neil Schemenauer | a765c12 | 2001-11-01 17:35:23 +0000 | [diff] [blame] | 426 | { |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 427 | PyGC_Head *gc; |
| 428 | PyGC_Head *next; |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 429 | |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 430 | /* March over unreachable. Move objects with finalizers into |
| 431 | * `finalizers`. |
| 432 | */ |
| 433 | for (gc = unreachable->gc.gc_next; gc != unreachable; gc = next) { |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 434 | PyObject *op = FROM_GC(gc); |
Jeremy Hylton | ce136e9 | 2003-04-04 19:59:06 +0000 | [diff] [blame] | 435 | |
Tim Peters | f6ae7a4 | 2003-04-05 18:40:50 +0000 | [diff] [blame] | 436 | assert(IS_TENTATIVELY_UNREACHABLE(op)); |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 437 | next = gc->gc.gc_next; |
Tim Peters | f6ae7a4 | 2003-04-05 18:40:50 +0000 | [diff] [blame] | 438 | |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 439 | if (has_finalizer(op)) { |
Tim Peters | e2d5918 | 2004-11-01 01:39:08 +0000 | [diff] [blame] | 440 | gc_list_move(gc, finalizers); |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 441 | gc->gc.gc_refs = GC_REACHABLE; |
Jeremy Hylton | ce136e9 | 2003-04-04 19:59:06 +0000 | [diff] [blame] | 442 | } |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 443 | } |
| 444 | } |
| 445 | |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 446 | /* A traversal callback for move_finalizer_reachable. */ |
| 447 | static int |
| 448 | visit_move(PyObject *op, PyGC_Head *tolist) |
| 449 | { |
| 450 | if (PyObject_IS_GC(op)) { |
Tim Peters | ea40563 | 2002-07-02 00:52:30 +0000 | [diff] [blame] | 451 | if (IS_TENTATIVELY_UNREACHABLE(op)) { |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 452 | PyGC_Head *gc = AS_GC(op); |
Tim Peters | e2d5918 | 2004-11-01 01:39:08 +0000 | [diff] [blame] | 453 | gc_list_move(gc, tolist); |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 454 | gc->gc.gc_refs = GC_REACHABLE; |
| 455 | } |
| 456 | } |
| 457 | return 0; |
| 458 | } |
| 459 | |
| 460 | /* Move objects that are reachable from finalizers, from the unreachable set |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 461 | * into finalizers set. |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 462 | */ |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 463 | static void |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 464 | move_finalizer_reachable(PyGC_Head *finalizers) |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 465 | { |
| 466 | traverseproc traverse; |
Tim Peters | 9e4ca10 | 2001-10-11 18:31:31 +0000 | [diff] [blame] | 467 | PyGC_Head *gc = finalizers->gc.gc_next; |
Tim Peters | bf384c2 | 2003-04-06 00:11:39 +0000 | [diff] [blame] | 468 | for (; gc != finalizers; gc = gc->gc.gc_next) { |
| 469 | /* Note that the finalizers list may grow during this. */ |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 470 | traverse = FROM_GC(gc)->ob_type->tp_traverse; |
Tim Peters | 8839617 | 2002-06-30 17:56:40 +0000 | [diff] [blame] | 471 | (void) traverse(FROM_GC(gc), |
Tim Peters | bf384c2 | 2003-04-06 00:11:39 +0000 | [diff] [blame] | 472 | (visitproc)visit_move, |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 473 | (void *)finalizers); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 474 | } |
| 475 | } |
| 476 | |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 477 | /* Clear all weakrefs to unreachable objects, and if such a weakref has a |
| 478 | * callback, invoke it if necessary. Note that it's possible for such |
| 479 | * weakrefs to be outside the unreachable set -- indeed, those are precisely |
| 480 | * the weakrefs whose callbacks must be invoked. See gc_weakref.txt for |
| 481 | * overview & some details. Some weakrefs with callbacks may be reclaimed |
| 482 | * directly by this routine; the number reclaimed is the return value. Other |
| 483 | * weakrefs with callbacks may be moved into the `old` generation. Objects |
| 484 | * moved into `old` have gc_refs set to GC_REACHABLE; the objects remaining in |
| 485 | * unreachable are left at GC_TENTATIVELY_UNREACHABLE. When this returns, |
| 486 | * no object in `unreachable` is weakly referenced anymore. |
Tim Peters | 403a203 | 2003-11-20 21:21:46 +0000 | [diff] [blame] | 487 | */ |
| 488 | static int |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 489 | handle_weakrefs(PyGC_Head *unreachable, PyGC_Head *old) |
Tim Peters | 403a203 | 2003-11-20 21:21:46 +0000 | [diff] [blame] | 490 | { |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 491 | PyGC_Head *gc; |
| 492 | PyObject *op; /* generally FROM_GC(gc) */ |
| 493 | PyWeakReference *wr; /* generally a cast of op */ |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 494 | PyGC_Head wrcb_to_call; /* weakrefs with callbacks to call */ |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 495 | PyGC_Head *next; |
Tim Peters | 403a203 | 2003-11-20 21:21:46 +0000 | [diff] [blame] | 496 | int num_freed = 0; |
| 497 | |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 498 | gc_list_init(&wrcb_to_call); |
Tim Peters | 403a203 | 2003-11-20 21:21:46 +0000 | [diff] [blame] | 499 | |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 500 | /* Clear all weakrefs to the objects in unreachable. If such a weakref |
| 501 | * 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] | 502 | * needs to be invoked. Note that we cannot invoke any callbacks until |
| 503 | * all weakrefs to unreachable objects are cleared, lest the callback |
| 504 | * resurrect an unreachable object via a still-active weakref. We |
| 505 | * make another pass over wrcb_to_call, invoking callbacks, after this |
| 506 | * pass completes. |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 507 | */ |
| 508 | for (gc = unreachable->gc.gc_next; gc != unreachable; gc = next) { |
| 509 | PyWeakReference **wrlist; |
| 510 | |
| 511 | op = FROM_GC(gc); |
| 512 | assert(IS_TENTATIVELY_UNREACHABLE(op)); |
| 513 | next = gc->gc.gc_next; |
| 514 | |
| 515 | if (! PyType_SUPPORTS_WEAKREFS(op->ob_type)) |
| 516 | continue; |
| 517 | |
| 518 | /* It supports weakrefs. Does it have any? */ |
| 519 | wrlist = (PyWeakReference **) |
| 520 | PyObject_GET_WEAKREFS_LISTPTR(op); |
| 521 | |
| 522 | /* `op` may have some weakrefs. March over the list, clear |
| 523 | * all the weakrefs, and move the weakrefs with callbacks |
Tim Peters | cc2a866 | 2004-10-31 22:12:43 +0000 | [diff] [blame] | 524 | * that must be called into wrcb_to_call. |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 525 | */ |
| 526 | for (wr = *wrlist; wr != NULL; wr = *wrlist) { |
| 527 | PyGC_Head *wrasgc; /* AS_GC(wr) */ |
| 528 | |
| 529 | /* _PyWeakref_ClearRef clears the weakref but leaves |
| 530 | * the callback pointer intact. Obscure: it also |
| 531 | * changes *wrlist. |
| 532 | */ |
| 533 | assert(wr->wr_object == op); |
| 534 | _PyWeakref_ClearRef(wr); |
| 535 | assert(wr->wr_object == Py_None); |
| 536 | if (wr->wr_callback == NULL) |
| 537 | continue; /* no callback */ |
| 538 | |
| 539 | /* Headache time. `op` is going away, and is weakly referenced by |
| 540 | * `wr`, which has a callback. Should the callback be invoked? If wr |
| 541 | * is also trash, no: |
| 542 | * |
| 543 | * 1. There's no need to call it. The object and the weakref are |
| 544 | * both going away, so it's legitimate to pretend the weakref is |
| 545 | * going away first. The user has to ensure a weakref outlives its |
| 546 | * referent if they want a guarantee that the wr callback will get |
| 547 | * invoked. |
| 548 | * |
| 549 | * 2. It may be catastrophic to call it. If the callback is also in |
| 550 | * cyclic trash (CT), then although the CT is unreachable from |
| 551 | * outside the current generation, CT may be reachable from the |
| 552 | * callback. Then the callback could resurrect insane objects. |
| 553 | * |
| 554 | * 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] | 555 | * wr is simply left in the unreachable set. Note that because we |
| 556 | * already called _PyWeakref_ClearRef(wr), its callback will never |
| 557 | * trigger. |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 558 | * |
| 559 | * OTOH, if wr isn't part of CT, we should invoke the callback: the |
| 560 | * weakref outlived the trash. Note that since wr isn't CT in this |
| 561 | * case, its callback can't be CT either -- wr acted as an external |
| 562 | * root to this generation, and therefore its callback did too. So |
| 563 | * nothing in CT is reachable from the callback either, so it's hard |
| 564 | * to imagine how calling it later could create a problem for us. wr |
| 565 | * is moved to wrcb_to_call in this case. |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 566 | */ |
Tim Peters | cc2a866 | 2004-10-31 22:12:43 +0000 | [diff] [blame] | 567 | if (IS_TENTATIVELY_UNREACHABLE(wr)) |
| 568 | continue; |
| 569 | assert(IS_REACHABLE(wr)); |
| 570 | |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 571 | /* Create a new reference so that wr can't go away |
| 572 | * before we can process it again. |
| 573 | */ |
| 574 | Py_INCREF(wr); |
| 575 | |
Tim Peters | cc2a866 | 2004-10-31 22:12:43 +0000 | [diff] [blame] | 576 | /* Move wr to wrcb_to_call, for the next pass. */ |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 577 | wrasgc = AS_GC(wr); |
Tim Peters | cc2a866 | 2004-10-31 22:12:43 +0000 | [diff] [blame] | 578 | assert(wrasgc != next); /* wrasgc is reachable, but |
| 579 | next isn't, so they can't |
| 580 | be the same */ |
Tim Peters | e2d5918 | 2004-11-01 01:39:08 +0000 | [diff] [blame] | 581 | gc_list_move(wrasgc, &wrcb_to_call); |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 582 | } |
| 583 | } |
| 584 | |
Tim Peters | cc2a866 | 2004-10-31 22:12:43 +0000 | [diff] [blame] | 585 | /* Invoke the callbacks we decided to honor. It's safe to invoke them |
| 586 | * because they can't reference unreachable objects. |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 587 | */ |
| 588 | while (! gc_list_is_empty(&wrcb_to_call)) { |
| 589 | PyObject *temp; |
| 590 | PyObject *callback; |
| 591 | |
| 592 | gc = wrcb_to_call.gc.gc_next; |
| 593 | op = FROM_GC(gc); |
| 594 | assert(IS_REACHABLE(op)); |
| 595 | assert(PyWeakref_Check(op)); |
| 596 | wr = (PyWeakReference *)op; |
| 597 | callback = wr->wr_callback; |
| 598 | assert(callback != NULL); |
| 599 | |
| 600 | /* copy-paste of weakrefobject.c's handle_callback() */ |
| 601 | temp = PyObject_CallFunction(callback, "O", wr); |
| 602 | if (temp == NULL) |
| 603 | PyErr_WriteUnraisable(callback); |
| 604 | else |
| 605 | Py_DECREF(temp); |
| 606 | |
| 607 | /* Give up the reference we created in the first pass. When |
| 608 | * 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] | 609 | * op's tp_dealloc will decref op->wr_callback too. Note |
| 610 | * that the refcount probably will hit 0 now, and because this |
| 611 | * weakref was reachable to begin with, gc didn't already |
| 612 | * add it to its count of freed objects. Example: a reachable |
| 613 | * weak value dict maps some key to this reachable weakref. |
| 614 | * The callback removes this key->weakref mapping from the |
| 615 | * dict, leaving no other references to the weakref (excepting |
| 616 | * ours). |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 617 | */ |
| 618 | Py_DECREF(op); |
| 619 | if (wrcb_to_call.gc.gc_next == gc) { |
| 620 | /* object is still alive -- move it */ |
Tim Peters | e2d5918 | 2004-11-01 01:39:08 +0000 | [diff] [blame] | 621 | gc_list_move(gc, old); |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 622 | } |
| 623 | else |
| 624 | ++num_freed; |
| 625 | } |
| 626 | |
Tim Peters | 403a203 | 2003-11-20 21:21:46 +0000 | [diff] [blame] | 627 | return num_freed; |
| 628 | } |
| 629 | |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 630 | static void |
Jeremy Hylton | 0625777 | 2000-08-31 15:10:24 +0000 | [diff] [blame] | 631 | debug_instance(char *msg, PyInstanceObject *inst) |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 632 | { |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 633 | char *cname; |
Neil Schemenauer | a765c12 | 2001-11-01 17:35:23 +0000 | [diff] [blame] | 634 | /* simple version of instance_repr */ |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 635 | PyObject *classname = inst->in_class->cl_name; |
| 636 | if (classname != NULL && PyString_Check(classname)) |
| 637 | cname = PyString_AsString(classname); |
| 638 | else |
| 639 | cname = "?"; |
Jeremy Hylton | 0625777 | 2000-08-31 15:10:24 +0000 | [diff] [blame] | 640 | PySys_WriteStderr("gc: %.100s <%.100s instance at %p>\n", |
| 641 | msg, cname, inst); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 642 | } |
| 643 | |
| 644 | static void |
Jeremy Hylton | 0625777 | 2000-08-31 15:10:24 +0000 | [diff] [blame] | 645 | debug_cycle(char *msg, PyObject *op) |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 646 | { |
| 647 | if ((debug & DEBUG_INSTANCES) && PyInstance_Check(op)) { |
Jeremy Hylton | 0625777 | 2000-08-31 15:10:24 +0000 | [diff] [blame] | 648 | debug_instance(msg, (PyInstanceObject *)op); |
Neil Schemenauer | 544de1e | 2000-09-22 15:22:38 +0000 | [diff] [blame] | 649 | } |
| 650 | else if (debug & DEBUG_OBJECTS) { |
Jeremy Hylton | 0625777 | 2000-08-31 15:10:24 +0000 | [diff] [blame] | 651 | PySys_WriteStderr("gc: %.100s <%.100s %p>\n", |
| 652 | msg, op->ob_type->tp_name, op); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 653 | } |
| 654 | } |
| 655 | |
Tim Peters | bf384c2 | 2003-04-06 00:11:39 +0000 | [diff] [blame] | 656 | /* Handle uncollectable garbage (cycles with finalizers, and stuff reachable |
| 657 | * only from such cycles). |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 658 | * If DEBUG_SAVEALL, all objects in finalizers are appended to the module |
| 659 | * garbage list (a Python list), else only the objects in finalizers with |
| 660 | * __del__ methods are appended to garbage. All objects in finalizers are |
| 661 | * merged into the old list regardless. |
Tim Peters | 259272b | 2003-04-06 19:41:39 +0000 | [diff] [blame] | 662 | * Returns 0 if all OK, <0 on error (out of memory to grow the garbage list). |
| 663 | * The finalizers list is made empty on a successful return. |
Tim Peters | bf384c2 | 2003-04-06 00:11:39 +0000 | [diff] [blame] | 664 | */ |
Tim Peters | 259272b | 2003-04-06 19:41:39 +0000 | [diff] [blame] | 665 | static int |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 666 | handle_finalizers(PyGC_Head *finalizers, PyGC_Head *old) |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 667 | { |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 668 | PyGC_Head *gc = finalizers->gc.gc_next; |
| 669 | |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 670 | if (garbage == NULL) { |
| 671 | garbage = PyList_New(0); |
Tim Peters | bf384c2 | 2003-04-06 00:11:39 +0000 | [diff] [blame] | 672 | if (garbage == NULL) |
| 673 | Py_FatalError("gc couldn't create gc.garbage list"); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 674 | } |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 675 | for (; gc != finalizers; gc = gc->gc.gc_next) { |
| 676 | PyObject *op = FROM_GC(gc); |
| 677 | |
| 678 | if ((debug & DEBUG_SAVEALL) || has_finalizer(op)) { |
| 679 | if (PyList_Append(garbage, op) < 0) |
| 680 | return -1; |
| 681 | } |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 682 | } |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 683 | |
Tim Peters | 259272b | 2003-04-06 19:41:39 +0000 | [diff] [blame] | 684 | gc_list_merge(finalizers, old); |
| 685 | return 0; |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 686 | } |
| 687 | |
Neil Schemenauer | 544de1e | 2000-09-22 15:22:38 +0000 | [diff] [blame] | 688 | /* Break reference cycles by clearing the containers involved. This is |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 689 | * 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] | 690 | * objects may be freed. It is possible I screwed something up here. |
| 691 | */ |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 692 | static void |
Jeremy Hylton | ce136e9 | 2003-04-04 19:59:06 +0000 | [diff] [blame] | 693 | delete_garbage(PyGC_Head *collectable, PyGC_Head *old) |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 694 | { |
| 695 | inquiry clear; |
| 696 | |
Jeremy Hylton | ce136e9 | 2003-04-04 19:59:06 +0000 | [diff] [blame] | 697 | while (!gc_list_is_empty(collectable)) { |
| 698 | PyGC_Head *gc = collectable->gc.gc_next; |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 699 | PyObject *op = FROM_GC(gc); |
Tim Peters | 8839617 | 2002-06-30 17:56:40 +0000 | [diff] [blame] | 700 | |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 701 | assert(IS_TENTATIVELY_UNREACHABLE(op)); |
Neil Schemenauer | 544de1e | 2000-09-22 15:22:38 +0000 | [diff] [blame] | 702 | if (debug & DEBUG_SAVEALL) { |
| 703 | PyList_Append(garbage, op); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 704 | } |
Neil Schemenauer | 544de1e | 2000-09-22 15:22:38 +0000 | [diff] [blame] | 705 | else { |
| 706 | if ((clear = op->ob_type->tp_clear) != NULL) { |
| 707 | Py_INCREF(op); |
Jeremy Hylton | 8a13518 | 2002-06-06 23:23:55 +0000 | [diff] [blame] | 708 | clear(op); |
Neil Schemenauer | 544de1e | 2000-09-22 15:22:38 +0000 | [diff] [blame] | 709 | Py_DECREF(op); |
| 710 | } |
| 711 | } |
Jeremy Hylton | ce136e9 | 2003-04-04 19:59:06 +0000 | [diff] [blame] | 712 | if (collectable->gc.gc_next == gc) { |
Neil Schemenauer | 544de1e | 2000-09-22 15:22:38 +0000 | [diff] [blame] | 713 | /* object is still alive, move it, it may die later */ |
Tim Peters | e2d5918 | 2004-11-01 01:39:08 +0000 | [diff] [blame] | 714 | gc_list_move(gc, old); |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 715 | gc->gc.gc_refs = GC_REACHABLE; |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 716 | } |
| 717 | } |
| 718 | } |
| 719 | |
| 720 | /* This is the main function. Read this to understand how the |
| 721 | * collection process works. */ |
| 722 | static long |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 723 | collect(int generation) |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 724 | { |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 725 | int i; |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 726 | long m = 0; /* # objects collected */ |
| 727 | long n = 0; /* # unreachable objects that couldn't be collected */ |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 728 | PyGC_Head *young; /* the generation we are examining */ |
| 729 | PyGC_Head *old; /* next older generation */ |
Tim Peters | 403a203 | 2003-11-20 21:21:46 +0000 | [diff] [blame] | 730 | PyGC_Head unreachable; /* non-problematic unreachable trash */ |
| 731 | PyGC_Head finalizers; /* objects with, & reachable from, __del__ */ |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 732 | PyGC_Head *gc; |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 733 | |
Tim Peters | 93ad66d | 2003-04-05 17:15:44 +0000 | [diff] [blame] | 734 | if (delstr == NULL) { |
| 735 | delstr = PyString_InternFromString("__del__"); |
| 736 | if (delstr == NULL) |
| 737 | Py_FatalError("gc couldn't allocate \"__del__\""); |
| 738 | } |
| 739 | |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 740 | if (debug & DEBUG_STATS) { |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 741 | PySys_WriteStderr("gc: collecting generation %d...\n", |
| 742 | generation); |
| 743 | PySys_WriteStderr("gc: objects in each generation:"); |
| 744 | for (i = 0; i < NUM_GENERATIONS; i++) { |
| 745 | PySys_WriteStderr(" %ld", gc_list_size(GEN_HEAD(i))); |
| 746 | } |
| 747 | PySys_WriteStderr("\n"); |
| 748 | } |
| 749 | |
| 750 | /* update collection and allocation counters */ |
| 751 | if (generation+1 < NUM_GENERATIONS) |
| 752 | generations[generation+1].count += 1; |
| 753 | for (i = 0; i <= generation; i++) |
Neil Schemenauer | c905164 | 2002-06-28 19:16:04 +0000 | [diff] [blame] | 754 | generations[i].count = 0; |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 755 | |
| 756 | /* merge younger generations with one we are currently collecting */ |
| 757 | for (i = 0; i < generation; i++) { |
| 758 | gc_list_merge(GEN_HEAD(i), GEN_HEAD(generation)); |
| 759 | } |
| 760 | |
| 761 | /* handy references */ |
| 762 | young = GEN_HEAD(generation); |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 763 | if (generation < NUM_GENERATIONS-1) |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 764 | old = GEN_HEAD(generation+1); |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 765 | else |
| 766 | old = young; |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 767 | |
| 768 | /* Using ob_refcnt and gc_refs, calculate which objects in the |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 769 | * container set are reachable from outside the set (i.e., have a |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 770 | * refcount greater than 0 when all the references within the |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 771 | * set are taken into account). |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 772 | */ |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 773 | update_refs(young); |
| 774 | subtract_refs(young); |
| 775 | |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 776 | /* Leave everything reachable from outside young in young, and move |
| 777 | * everything else (in young) to unreachable. |
| 778 | * NOTE: This used to move the reachable objects into a reachable |
| 779 | * set instead. But most things usually turn out to be reachable, |
| 780 | * so it's more efficient to move the unreachable things. |
| 781 | */ |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 782 | gc_list_init(&unreachable); |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 783 | move_unreachable(young, &unreachable); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 784 | |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 785 | /* Move reachable objects to next generation. */ |
| 786 | if (young != old) |
| 787 | gc_list_merge(young, old); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 788 | |
Tim Peters | 19b74c7 | 2002-07-01 03:52:19 +0000 | [diff] [blame] | 789 | /* All objects in unreachable are trash, but objects reachable from |
| 790 | * finalizers can't safely be deleted. Python programmers should take |
| 791 | * care not to create such things. For Python, finalizers means |
Tim Peters | 403a203 | 2003-11-20 21:21:46 +0000 | [diff] [blame] | 792 | * instance objects with __del__ methods. Weakrefs with callbacks |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 793 | * can also call arbitrary Python code but they will be dealt with by |
| 794 | * handle_weakrefs(). |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 795 | */ |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 796 | gc_list_init(&finalizers); |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 797 | move_finalizers(&unreachable, &finalizers); |
Tim Peters | bf384c2 | 2003-04-06 00:11:39 +0000 | [diff] [blame] | 798 | /* finalizers contains the unreachable objects with a finalizer; |
Tim Peters | 403a203 | 2003-11-20 21:21:46 +0000 | [diff] [blame] | 799 | * unreachable objects reachable *from* those are also uncollectable, |
| 800 | * and we move those into the finalizers list too. |
Tim Peters | bf384c2 | 2003-04-06 00:11:39 +0000 | [diff] [blame] | 801 | */ |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 802 | move_finalizer_reachable(&finalizers); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 803 | |
| 804 | /* Collect statistics on collectable objects found and print |
Tim Peters | 403a203 | 2003-11-20 21:21:46 +0000 | [diff] [blame] | 805 | * debugging information. |
| 806 | */ |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 807 | for (gc = unreachable.gc.gc_next; gc != &unreachable; |
Tim Peters | 9e4ca10 | 2001-10-11 18:31:31 +0000 | [diff] [blame] | 808 | gc = gc->gc.gc_next) { |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 809 | m++; |
Jeremy Hylton | 0625777 | 2000-08-31 15:10:24 +0000 | [diff] [blame] | 810 | if (debug & DEBUG_COLLECTABLE) { |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 811 | debug_cycle("collectable", FROM_GC(gc)); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 812 | } |
| 813 | } |
Tim Peters | ead8b7a | 2004-10-30 23:09:22 +0000 | [diff] [blame] | 814 | |
| 815 | /* Clear weakrefs and invoke callbacks as necessary. */ |
| 816 | m += handle_weakrefs(&unreachable, old); |
| 817 | |
Tim Peters | fb2ab4d | 2003-04-07 22:41:24 +0000 | [diff] [blame] | 818 | /* Call tp_clear on objects in the unreachable set. This will cause |
| 819 | * the reference cycles to be broken. It may also cause some objects |
| 820 | * in finalizers to be freed. |
| 821 | */ |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 822 | delete_garbage(&unreachable, old); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 823 | |
| 824 | /* Collect statistics on uncollectable objects found and print |
| 825 | * debugging information. */ |
Tim Peters | 50c61d5 | 2003-04-06 01:50:50 +0000 | [diff] [blame] | 826 | for (gc = finalizers.gc.gc_next; |
Tim Peters | bf384c2 | 2003-04-06 00:11:39 +0000 | [diff] [blame] | 827 | gc != &finalizers; |
| 828 | gc = gc->gc.gc_next) { |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 829 | n++; |
Tim Peters | bf384c2 | 2003-04-06 00:11:39 +0000 | [diff] [blame] | 830 | if (debug & DEBUG_UNCOLLECTABLE) |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 831 | debug_cycle("uncollectable", FROM_GC(gc)); |
Tim Peters | bf384c2 | 2003-04-06 00:11:39 +0000 | [diff] [blame] | 832 | } |
Jeremy Hylton | 0625777 | 2000-08-31 15:10:24 +0000 | [diff] [blame] | 833 | if (debug & DEBUG_STATS) { |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 834 | if (m == 0 && n == 0) { |
Jeremy Hylton | 0625777 | 2000-08-31 15:10:24 +0000 | [diff] [blame] | 835 | PySys_WriteStderr("gc: done.\n"); |
Neil Schemenauer | 544de1e | 2000-09-22 15:22:38 +0000 | [diff] [blame] | 836 | } |
| 837 | else { |
Jeremy Hylton | 0625777 | 2000-08-31 15:10:24 +0000 | [diff] [blame] | 838 | PySys_WriteStderr( |
| 839 | "gc: done, %ld unreachable, %ld uncollectable.\n", |
| 840 | n+m, n); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 841 | } |
| 842 | } |
| 843 | |
| 844 | /* Append instances in the uncollectable set to a Python |
| 845 | * reachable list of garbage. The programmer has to deal with |
Tim Peters | bf384c2 | 2003-04-06 00:11:39 +0000 | [diff] [blame] | 846 | * this if they insist on creating this type of structure. |
| 847 | */ |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 848 | (void)handle_finalizers(&finalizers, old); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 849 | |
Jeremy Hylton | b709df3 | 2000-09-01 02:47:25 +0000 | [diff] [blame] | 850 | if (PyErr_Occurred()) { |
Tim Peters | f6b8045 | 2003-04-07 19:21:15 +0000 | [diff] [blame] | 851 | if (gc_str == NULL) |
Tim Peters | fb2ab4d | 2003-04-07 22:41:24 +0000 | [diff] [blame] | 852 | gc_str = PyString_FromString("garbage collection"); |
Jeremy Hylton | b709df3 | 2000-09-01 02:47:25 +0000 | [diff] [blame] | 853 | PyErr_WriteUnraisable(gc_str); |
| 854 | Py_FatalError("unexpected exception during garbage collection"); |
| 855 | } |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 856 | return n+m; |
| 857 | } |
| 858 | |
| 859 | static long |
| 860 | collect_generations(void) |
| 861 | { |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 862 | int i; |
Vladimir Marangozov | b16714b | 2000-07-10 05:37:39 +0000 | [diff] [blame] | 863 | long n = 0; |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 864 | |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 865 | /* Find the oldest generation (higest numbered) where the count |
| 866 | * exceeds the threshold. Objects in the that generation and |
| 867 | * generations younger than it will be collected. */ |
| 868 | for (i = NUM_GENERATIONS-1; i >= 0; i--) { |
| 869 | if (generations[i].count > generations[i].threshold) { |
| 870 | n = collect(i); |
| 871 | break; |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 872 | } |
| 873 | } |
| 874 | return n; |
| 875 | } |
| 876 | |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 877 | PyDoc_STRVAR(gc_enable__doc__, |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 878 | "enable() -> None\n" |
| 879 | "\n" |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 880 | "Enable automatic garbage collection.\n"); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 881 | |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 882 | static PyObject * |
Tim Peters | 50c61d5 | 2003-04-06 01:50:50 +0000 | [diff] [blame] | 883 | gc_enable(PyObject *self, PyObject *noargs) |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 884 | { |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 885 | enabled = 1; |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 886 | Py_INCREF(Py_None); |
| 887 | return Py_None; |
| 888 | } |
| 889 | |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 890 | PyDoc_STRVAR(gc_disable__doc__, |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 891 | "disable() -> None\n" |
| 892 | "\n" |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 893 | "Disable automatic garbage collection.\n"); |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 894 | |
| 895 | static PyObject * |
Tim Peters | 50c61d5 | 2003-04-06 01:50:50 +0000 | [diff] [blame] | 896 | gc_disable(PyObject *self, PyObject *noargs) |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 897 | { |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 898 | enabled = 0; |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 899 | Py_INCREF(Py_None); |
| 900 | return Py_None; |
| 901 | } |
| 902 | |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 903 | PyDoc_STRVAR(gc_isenabled__doc__, |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 904 | "isenabled() -> status\n" |
| 905 | "\n" |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 906 | "Returns true if automatic garbage collection is enabled.\n"); |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 907 | |
| 908 | static PyObject * |
Tim Peters | 50c61d5 | 2003-04-06 01:50:50 +0000 | [diff] [blame] | 909 | gc_isenabled(PyObject *self, PyObject *noargs) |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 910 | { |
Raymond Hettinger | 674d56b | 2004-01-04 04:00:13 +0000 | [diff] [blame] | 911 | return PyBool_FromLong((long)enabled); |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 912 | } |
| 913 | |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 914 | PyDoc_STRVAR(gc_collect__doc__, |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 915 | "collect() -> n\n" |
| 916 | "\n" |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 917 | "Run a full collection. The number of unreachable objects is returned.\n"); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 918 | |
| 919 | static PyObject * |
Tim Peters | 50c61d5 | 2003-04-06 01:50:50 +0000 | [diff] [blame] | 920 | gc_collect(PyObject *self, PyObject *noargs) |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 921 | { |
| 922 | long n; |
| 923 | |
Tim Peters | 50c61d5 | 2003-04-06 01:50:50 +0000 | [diff] [blame] | 924 | if (collecting) |
Neil Schemenauer | e8c40cb | 2001-10-31 23:09:35 +0000 | [diff] [blame] | 925 | n = 0; /* already collecting, don't do anything */ |
Neil Schemenauer | e8c40cb | 2001-10-31 23:09:35 +0000 | [diff] [blame] | 926 | else { |
| 927 | collecting = 1; |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 928 | n = collect(NUM_GENERATIONS - 1); |
Neil Schemenauer | e8c40cb | 2001-10-31 23:09:35 +0000 | [diff] [blame] | 929 | collecting = 0; |
| 930 | } |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 931 | |
Neil Schemenauer | 7760cff | 2000-09-22 22:35:36 +0000 | [diff] [blame] | 932 | return Py_BuildValue("l", n); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 933 | } |
| 934 | |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 935 | PyDoc_STRVAR(gc_set_debug__doc__, |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 936 | "set_debug(flags) -> None\n" |
| 937 | "\n" |
| 938 | "Set the garbage collection debugging flags. Debugging information is\n" |
| 939 | "written to sys.stderr.\n" |
| 940 | "\n" |
| 941 | "flags is an integer and can have the following bits turned on:\n" |
| 942 | "\n" |
| 943 | " DEBUG_STATS - Print statistics during collection.\n" |
| 944 | " DEBUG_COLLECTABLE - Print collectable objects found.\n" |
| 945 | " DEBUG_UNCOLLECTABLE - Print unreachable but uncollectable objects found.\n" |
| 946 | " DEBUG_INSTANCES - Print instance objects.\n" |
| 947 | " DEBUG_OBJECTS - Print objects other than instances.\n" |
Neil Schemenauer | 544de1e | 2000-09-22 15:22:38 +0000 | [diff] [blame] | 948 | " 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] | 949 | " DEBUG_LEAK - Debug leaking programs (everything but STATS).\n"); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 950 | |
| 951 | static PyObject * |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 952 | gc_set_debug(PyObject *self, PyObject *args) |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 953 | { |
Neil Schemenauer | 7760cff | 2000-09-22 22:35:36 +0000 | [diff] [blame] | 954 | if (!PyArg_ParseTuple(args, "i:set_debug", &debug)) |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 955 | return NULL; |
| 956 | |
| 957 | Py_INCREF(Py_None); |
| 958 | return Py_None; |
| 959 | } |
| 960 | |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 961 | PyDoc_STRVAR(gc_get_debug__doc__, |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 962 | "get_debug() -> flags\n" |
| 963 | "\n" |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 964 | "Get the garbage collection debugging flags.\n"); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 965 | |
| 966 | static PyObject * |
Tim Peters | 50c61d5 | 2003-04-06 01:50:50 +0000 | [diff] [blame] | 967 | gc_get_debug(PyObject *self, PyObject *noargs) |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 968 | { |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 969 | return Py_BuildValue("i", debug); |
| 970 | } |
| 971 | |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 972 | PyDoc_STRVAR(gc_set_thresh__doc__, |
Neal Norwitz | 2a47c0f | 2002-01-29 00:53:41 +0000 | [diff] [blame] | 973 | "set_threshold(threshold0, [threshold1, threshold2]) -> None\n" |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 974 | "\n" |
| 975 | "Sets the collection thresholds. Setting threshold0 to zero disables\n" |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 976 | "collection.\n"); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 977 | |
| 978 | static PyObject * |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 979 | gc_set_thresh(PyObject *self, PyObject *args) |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 980 | { |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 981 | int i; |
| 982 | if (!PyArg_ParseTuple(args, "i|ii:set_threshold", |
| 983 | &generations[0].threshold, |
| 984 | &generations[1].threshold, |
| 985 | &generations[2].threshold)) |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 986 | return NULL; |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 987 | for (i = 2; i < NUM_GENERATIONS; i++) { |
| 988 | /* generations higher than 2 get the same threshold */ |
| 989 | generations[i].threshold = generations[2].threshold; |
| 990 | } |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 991 | |
| 992 | Py_INCREF(Py_None); |
| 993 | return Py_None; |
| 994 | } |
| 995 | |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 996 | PyDoc_STRVAR(gc_get_thresh__doc__, |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 997 | "get_threshold() -> (threshold0, threshold1, threshold2)\n" |
| 998 | "\n" |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 999 | "Return the current collection thresholds\n"); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 1000 | |
| 1001 | static PyObject * |
Tim Peters | 50c61d5 | 2003-04-06 01:50:50 +0000 | [diff] [blame] | 1002 | gc_get_thresh(PyObject *self, PyObject *noargs) |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 1003 | { |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 1004 | return Py_BuildValue("(iii)", |
| 1005 | generations[0].threshold, |
| 1006 | generations[1].threshold, |
| 1007 | generations[2].threshold); |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 1008 | } |
| 1009 | |
Neil Schemenauer | 48c7034 | 2001-08-09 15:38:31 +0000 | [diff] [blame] | 1010 | static int |
Martin v. Löwis | 560da62 | 2001-11-24 09:24:51 +0000 | [diff] [blame] | 1011 | referrersvisit(PyObject* obj, PyObject *objs) |
Neil Schemenauer | 48c7034 | 2001-08-09 15:38:31 +0000 | [diff] [blame] | 1012 | { |
Martin v. Löwis | c8fe77b | 2001-11-29 18:08:31 +0000 | [diff] [blame] | 1013 | int i; |
| 1014 | for (i = 0; i < PyTuple_GET_SIZE(objs); i++) |
| 1015 | if (PyTuple_GET_ITEM(objs, i) == obj) |
| 1016 | return 1; |
Neil Schemenauer | 48c7034 | 2001-08-09 15:38:31 +0000 | [diff] [blame] | 1017 | return 0; |
| 1018 | } |
| 1019 | |
Neil Schemenauer | 17e7be6 | 2001-08-10 14:46:47 +0000 | [diff] [blame] | 1020 | static int |
Martin v. Löwis | 560da62 | 2001-11-24 09:24:51 +0000 | [diff] [blame] | 1021 | gc_referrers_for(PyObject *objs, PyGC_Head *list, PyObject *resultlist) |
Neil Schemenauer | 48c7034 | 2001-08-09 15:38:31 +0000 | [diff] [blame] | 1022 | { |
| 1023 | PyGC_Head *gc; |
| 1024 | PyObject *obj; |
| 1025 | traverseproc traverse; |
Tim Peters | 9e4ca10 | 2001-10-11 18:31:31 +0000 | [diff] [blame] | 1026 | 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] | 1027 | obj = FROM_GC(gc); |
Neil Schemenauer | 48c7034 | 2001-08-09 15:38:31 +0000 | [diff] [blame] | 1028 | traverse = obj->ob_type->tp_traverse; |
| 1029 | if (obj == objs || obj == resultlist) |
| 1030 | continue; |
Martin v. Löwis | 560da62 | 2001-11-24 09:24:51 +0000 | [diff] [blame] | 1031 | if (traverse(obj, (visitproc)referrersvisit, objs)) { |
Neil Schemenauer | 17e7be6 | 2001-08-10 14:46:47 +0000 | [diff] [blame] | 1032 | if (PyList_Append(resultlist, obj) < 0) |
| 1033 | return 0; /* error */ |
Neil Schemenauer | 48c7034 | 2001-08-09 15:38:31 +0000 | [diff] [blame] | 1034 | } |
| 1035 | } |
Neil Schemenauer | 17e7be6 | 2001-08-10 14:46:47 +0000 | [diff] [blame] | 1036 | return 1; /* no error */ |
Neil Schemenauer | 48c7034 | 2001-08-09 15:38:31 +0000 | [diff] [blame] | 1037 | } |
| 1038 | |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 1039 | PyDoc_STRVAR(gc_get_referrers__doc__, |
Martin v. Löwis | 560da62 | 2001-11-24 09:24:51 +0000 | [diff] [blame] | 1040 | "get_referrers(*objs) -> list\n\ |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 1041 | Return the list of objects that directly refer to any of objs."); |
Neil Schemenauer | 48c7034 | 2001-08-09 15:38:31 +0000 | [diff] [blame] | 1042 | |
Neil Schemenauer | 17e7be6 | 2001-08-10 14:46:47 +0000 | [diff] [blame] | 1043 | static PyObject * |
Martin v. Löwis | 560da62 | 2001-11-24 09:24:51 +0000 | [diff] [blame] | 1044 | gc_get_referrers(PyObject *self, PyObject *args) |
Neil Schemenauer | 48c7034 | 2001-08-09 15:38:31 +0000 | [diff] [blame] | 1045 | { |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 1046 | int i; |
Neil Schemenauer | 48c7034 | 2001-08-09 15:38:31 +0000 | [diff] [blame] | 1047 | PyObject *result = PyList_New(0); |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 1048 | for (i = 0; i < NUM_GENERATIONS; i++) { |
| 1049 | if (!(gc_referrers_for(args, GEN_HEAD(i), result))) { |
| 1050 | Py_DECREF(result); |
| 1051 | return NULL; |
| 1052 | } |
Neil Schemenauer | 17e7be6 | 2001-08-10 14:46:47 +0000 | [diff] [blame] | 1053 | } |
Neil Schemenauer | 48c7034 | 2001-08-09 15:38:31 +0000 | [diff] [blame] | 1054 | return result; |
| 1055 | } |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 1056 | |
Tim Peters | 0f81ab6 | 2003-04-08 16:39:48 +0000 | [diff] [blame] | 1057 | /* 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] | 1058 | static int |
Tim Peters | 730f553 | 2003-04-08 17:17:17 +0000 | [diff] [blame] | 1059 | referentsvisit(PyObject *obj, PyObject *list) |
Jeremy Hylton | 5bd378b | 2003-04-03 16:28:38 +0000 | [diff] [blame] | 1060 | { |
Tim Peters | 0f81ab6 | 2003-04-08 16:39:48 +0000 | [diff] [blame] | 1061 | return PyList_Append(list, obj) < 0; |
Jeremy Hylton | 5bd378b | 2003-04-03 16:28:38 +0000 | [diff] [blame] | 1062 | } |
| 1063 | |
Tim Peters | 730f553 | 2003-04-08 17:17:17 +0000 | [diff] [blame] | 1064 | PyDoc_STRVAR(gc_get_referents__doc__, |
| 1065 | "get_referents(*objs) -> list\n\ |
Jeremy Hylton | 059b094 | 2003-04-03 16:29:13 +0000 | [diff] [blame] | 1066 | Return the list of objects that are directly referred to by objs."); |
Jeremy Hylton | 5bd378b | 2003-04-03 16:28:38 +0000 | [diff] [blame] | 1067 | |
| 1068 | static PyObject * |
Tim Peters | 730f553 | 2003-04-08 17:17:17 +0000 | [diff] [blame] | 1069 | gc_get_referents(PyObject *self, PyObject *args) |
Jeremy Hylton | 5bd378b | 2003-04-03 16:28:38 +0000 | [diff] [blame] | 1070 | { |
| 1071 | int i; |
| 1072 | PyObject *result = PyList_New(0); |
Tim Peters | 0f81ab6 | 2003-04-08 16:39:48 +0000 | [diff] [blame] | 1073 | |
| 1074 | if (result == NULL) |
| 1075 | return NULL; |
| 1076 | |
Jeremy Hylton | 5bd378b | 2003-04-03 16:28:38 +0000 | [diff] [blame] | 1077 | for (i = 0; i < PyTuple_GET_SIZE(args); i++) { |
Tim Peters | 0f81ab6 | 2003-04-08 16:39:48 +0000 | [diff] [blame] | 1078 | traverseproc traverse; |
Tim Peters | 93ad66d | 2003-04-05 17:15:44 +0000 | [diff] [blame] | 1079 | PyObject *obj = PyTuple_GET_ITEM(args, i); |
Tim Peters | 0f81ab6 | 2003-04-08 16:39:48 +0000 | [diff] [blame] | 1080 | |
| 1081 | if (! PyObject_IS_GC(obj)) |
Jeremy Hylton | 5bd378b | 2003-04-03 16:28:38 +0000 | [diff] [blame] | 1082 | continue; |
Tim Peters | 0f81ab6 | 2003-04-08 16:39:48 +0000 | [diff] [blame] | 1083 | traverse = obj->ob_type->tp_traverse; |
| 1084 | if (! traverse) |
| 1085 | continue; |
Tim Peters | 730f553 | 2003-04-08 17:17:17 +0000 | [diff] [blame] | 1086 | if (traverse(obj, (visitproc)referentsvisit, result)) { |
Tim Peters | 0f81ab6 | 2003-04-08 16:39:48 +0000 | [diff] [blame] | 1087 | Py_DECREF(result); |
Jeremy Hylton | 5bd378b | 2003-04-03 16:28:38 +0000 | [diff] [blame] | 1088 | return NULL; |
Tim Peters | 0f81ab6 | 2003-04-08 16:39:48 +0000 | [diff] [blame] | 1089 | } |
Jeremy Hylton | 5bd378b | 2003-04-03 16:28:38 +0000 | [diff] [blame] | 1090 | } |
| 1091 | return result; |
| 1092 | } |
| 1093 | |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 1094 | PyDoc_STRVAR(gc_get_objects__doc__, |
Neil Schemenauer | c7c8d8e | 2001-08-09 15:58:59 +0000 | [diff] [blame] | 1095 | "get_objects() -> [...]\n" |
| 1096 | "\n" |
| 1097 | "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] | 1098 | "returned).\n"); |
Neil Schemenauer | c7c8d8e | 2001-08-09 15:58:59 +0000 | [diff] [blame] | 1099 | |
Neil Schemenauer | c7c8d8e | 2001-08-09 15:58:59 +0000 | [diff] [blame] | 1100 | static PyObject * |
Tim Peters | 50c61d5 | 2003-04-06 01:50:50 +0000 | [diff] [blame] | 1101 | gc_get_objects(PyObject *self, PyObject *noargs) |
Neil Schemenauer | c7c8d8e | 2001-08-09 15:58:59 +0000 | [diff] [blame] | 1102 | { |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 1103 | int i; |
Neil Schemenauer | c7c8d8e | 2001-08-09 15:58:59 +0000 | [diff] [blame] | 1104 | PyObject* result; |
| 1105 | |
Neil Schemenauer | c7c8d8e | 2001-08-09 15:58:59 +0000 | [diff] [blame] | 1106 | result = PyList_New(0); |
Tim Peters | 50c61d5 | 2003-04-06 01:50:50 +0000 | [diff] [blame] | 1107 | if (result == NULL) |
Martin v. Löwis | f8a6f24 | 2001-12-02 18:31:02 +0000 | [diff] [blame] | 1108 | return NULL; |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 1109 | for (i = 0; i < NUM_GENERATIONS; i++) { |
| 1110 | if (append_objects(result, GEN_HEAD(i))) { |
| 1111 | Py_DECREF(result); |
| 1112 | return NULL; |
| 1113 | } |
Martin v. Löwis | 155aad1 | 2001-12-02 12:21:34 +0000 | [diff] [blame] | 1114 | } |
Neil Schemenauer | c7c8d8e | 2001-08-09 15:58:59 +0000 | [diff] [blame] | 1115 | return result; |
| 1116 | } |
| 1117 | |
| 1118 | |
Martin v. Löwis | 14f8b4c | 2002-06-13 20:33:02 +0000 | [diff] [blame] | 1119 | PyDoc_STRVAR(gc__doc__, |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 1120 | "This module provides access to the garbage collector for reference cycles.\n" |
| 1121 | "\n" |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 1122 | "enable() -- Enable automatic garbage collection.\n" |
| 1123 | "disable() -- Disable automatic garbage collection.\n" |
| 1124 | "isenabled() -- Returns true if automatic collection is enabled.\n" |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 1125 | "collect() -- Do a full collection right now.\n" |
| 1126 | "set_debug() -- Set debugging flags.\n" |
| 1127 | "get_debug() -- Get debugging flags.\n" |
| 1128 | "set_threshold() -- Set the collection thresholds.\n" |
| 1129 | "get_threshold() -- Return the current the collection thresholds.\n" |
Neil Schemenauer | c7c8d8e | 2001-08-09 15:58:59 +0000 | [diff] [blame] | 1130 | "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] | 1131 | "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] | 1132 | "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] | 1133 | |
| 1134 | static PyMethodDef GcMethods[] = { |
Tim Peters | 50c61d5 | 2003-04-06 01:50:50 +0000 | [diff] [blame] | 1135 | {"enable", gc_enable, METH_NOARGS, gc_enable__doc__}, |
| 1136 | {"disable", gc_disable, METH_NOARGS, gc_disable__doc__}, |
| 1137 | {"isenabled", gc_isenabled, METH_NOARGS, gc_isenabled__doc__}, |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 1138 | {"set_debug", gc_set_debug, METH_VARARGS, gc_set_debug__doc__}, |
Tim Peters | 50c61d5 | 2003-04-06 01:50:50 +0000 | [diff] [blame] | 1139 | {"get_debug", gc_get_debug, METH_NOARGS, gc_get_debug__doc__}, |
Vladimir Marangozov | f9d20c3 | 2000-08-06 22:45:31 +0000 | [diff] [blame] | 1140 | {"set_threshold", gc_set_thresh, METH_VARARGS, gc_set_thresh__doc__}, |
Tim Peters | 50c61d5 | 2003-04-06 01:50:50 +0000 | [diff] [blame] | 1141 | {"get_threshold", gc_get_thresh, METH_NOARGS, gc_get_thresh__doc__}, |
| 1142 | {"collect", gc_collect, METH_NOARGS, gc_collect__doc__}, |
| 1143 | {"get_objects", gc_get_objects,METH_NOARGS, gc_get_objects__doc__}, |
Martin v. Löwis | 560da62 | 2001-11-24 09:24:51 +0000 | [diff] [blame] | 1144 | {"get_referrers", gc_get_referrers, METH_VARARGS, |
| 1145 | gc_get_referrers__doc__}, |
Tim Peters | 730f553 | 2003-04-08 17:17:17 +0000 | [diff] [blame] | 1146 | {"get_referents", gc_get_referents, METH_VARARGS, |
| 1147 | gc_get_referents__doc__}, |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 1148 | {NULL, NULL} /* Sentinel */ |
| 1149 | }; |
| 1150 | |
Jason Tishler | 6bc06ec | 2003-09-04 11:59:50 +0000 | [diff] [blame] | 1151 | PyMODINIT_FUNC |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 1152 | initgc(void) |
| 1153 | { |
| 1154 | PyObject *m; |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 1155 | |
| 1156 | m = Py_InitModule4("gc", |
| 1157 | GcMethods, |
| 1158 | gc__doc__, |
| 1159 | NULL, |
| 1160 | PYTHON_API_VERSION); |
Neal Norwitz | 1ac754f | 2006-01-19 06:09:39 +0000 | [diff] [blame^] | 1161 | if (m == NULL) |
| 1162 | return; |
Tim Peters | 1155887 | 2003-04-06 23:30:52 +0000 | [diff] [blame] | 1163 | |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 1164 | if (garbage == NULL) { |
| 1165 | garbage = PyList_New(0); |
Tim Peters | 1155887 | 2003-04-06 23:30:52 +0000 | [diff] [blame] | 1166 | if (garbage == NULL) |
| 1167 | return; |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 1168 | } |
Neil Schemenauer | 3b1cbf9 | 2005-06-18 17:37:06 +0000 | [diff] [blame] | 1169 | Py_INCREF(garbage); |
Tim Peters | 1155887 | 2003-04-06 23:30:52 +0000 | [diff] [blame] | 1170 | if (PyModule_AddObject(m, "garbage", garbage) < 0) |
| 1171 | return; |
| 1172 | #define ADD_INT(NAME) if (PyModule_AddIntConstant(m, #NAME, NAME) < 0) return |
| 1173 | ADD_INT(DEBUG_STATS); |
| 1174 | ADD_INT(DEBUG_COLLECTABLE); |
| 1175 | ADD_INT(DEBUG_UNCOLLECTABLE); |
| 1176 | ADD_INT(DEBUG_INSTANCES); |
| 1177 | ADD_INT(DEBUG_OBJECTS); |
| 1178 | ADD_INT(DEBUG_SAVEALL); |
| 1179 | ADD_INT(DEBUG_LEAK); |
| 1180 | #undef ADD_INT |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 1181 | } |
| 1182 | |
Guido van Rossum | e13ddc9 | 2003-04-17 17:29:22 +0000 | [diff] [blame] | 1183 | /* API to invoke gc.collect() from C */ |
| 1184 | long |
| 1185 | PyGC_Collect(void) |
| 1186 | { |
| 1187 | long n; |
| 1188 | |
| 1189 | if (collecting) |
| 1190 | n = 0; /* already collecting, don't do anything */ |
| 1191 | else { |
| 1192 | collecting = 1; |
| 1193 | n = collect(NUM_GENERATIONS - 1); |
| 1194 | collecting = 0; |
| 1195 | } |
| 1196 | |
| 1197 | return n; |
| 1198 | } |
| 1199 | |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1200 | /* for debugging */ |
Guido van Rossum | e13ddc9 | 2003-04-17 17:29:22 +0000 | [diff] [blame] | 1201 | void |
| 1202 | _PyGC_Dump(PyGC_Head *g) |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1203 | { |
| 1204 | _PyObject_Dump(FROM_GC(g)); |
| 1205 | } |
| 1206 | |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1207 | /* extension modules might be compiled with GC support so these |
| 1208 | functions must always be available */ |
| 1209 | |
Neil Schemenauer | fec4eb1 | 2002-04-12 02:41:03 +0000 | [diff] [blame] | 1210 | #undef PyObject_GC_Track |
| 1211 | #undef PyObject_GC_UnTrack |
| 1212 | #undef PyObject_GC_Del |
| 1213 | #undef _PyObject_GC_Malloc |
| 1214 | |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1215 | void |
Neil Schemenauer | fec4eb1 | 2002-04-12 02:41:03 +0000 | [diff] [blame] | 1216 | PyObject_GC_Track(void *op) |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1217 | { |
| 1218 | _PyObject_GC_TRACK(op); |
| 1219 | } |
| 1220 | |
Neil Schemenauer | fec4eb1 | 2002-04-12 02:41:03 +0000 | [diff] [blame] | 1221 | /* for binary compatibility with 2.2 */ |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1222 | void |
Neil Schemenauer | fec4eb1 | 2002-04-12 02:41:03 +0000 | [diff] [blame] | 1223 | _PyObject_GC_Track(PyObject *op) |
| 1224 | { |
| 1225 | PyObject_GC_Track(op); |
| 1226 | } |
| 1227 | |
| 1228 | void |
| 1229 | PyObject_GC_UnTrack(void *op) |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1230 | { |
Tim Peters | 803526b | 2002-07-07 05:13:56 +0000 | [diff] [blame] | 1231 | /* Obscure: the Py_TRASHCAN mechanism requires that we be able to |
| 1232 | * call PyObject_GC_UnTrack twice on an object. |
| 1233 | */ |
Neil Schemenauer | a2b11ec | 2002-05-21 15:53:24 +0000 | [diff] [blame] | 1234 | if (IS_TRACKED(op)) |
Guido van Rossum | ff413af | 2002-03-28 20:34:59 +0000 | [diff] [blame] | 1235 | _PyObject_GC_UNTRACK(op); |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1236 | } |
| 1237 | |
Neil Schemenauer | fec4eb1 | 2002-04-12 02:41:03 +0000 | [diff] [blame] | 1238 | /* for binary compatibility with 2.2 */ |
| 1239 | void |
| 1240 | _PyObject_GC_UnTrack(PyObject *op) |
| 1241 | { |
| 1242 | PyObject_GC_UnTrack(op); |
| 1243 | } |
| 1244 | |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1245 | PyObject * |
Neil Schemenauer | fec4eb1 | 2002-04-12 02:41:03 +0000 | [diff] [blame] | 1246 | _PyObject_GC_Malloc(size_t basicsize) |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1247 | { |
| 1248 | PyObject *op; |
Neil Schemenauer | fec4eb1 | 2002-04-12 02:41:03 +0000 | [diff] [blame] | 1249 | PyGC_Head *g = PyObject_MALLOC(sizeof(PyGC_Head) + basicsize); |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1250 | if (g == NULL) |
Jeremy Hylton | 8a13518 | 2002-06-06 23:23:55 +0000 | [diff] [blame] | 1251 | return PyErr_NoMemory(); |
Tim Peters | ea40563 | 2002-07-02 00:52:30 +0000 | [diff] [blame] | 1252 | g->gc.gc_refs = GC_UNTRACKED; |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 1253 | generations[0].count++; /* number of allocated GC objects */ |
| 1254 | if (generations[0].count > generations[0].threshold && |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1255 | enabled && |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 1256 | generations[0].threshold && |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1257 | !collecting && |
| 1258 | !PyErr_Occurred()) { |
| 1259 | collecting = 1; |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 1260 | collect_generations(); |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1261 | collecting = 0; |
| 1262 | } |
| 1263 | op = FROM_GC(g); |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1264 | return op; |
| 1265 | } |
| 1266 | |
| 1267 | PyObject * |
| 1268 | _PyObject_GC_New(PyTypeObject *tp) |
| 1269 | { |
Neil Schemenauer | fec4eb1 | 2002-04-12 02:41:03 +0000 | [diff] [blame] | 1270 | PyObject *op = _PyObject_GC_Malloc(_PyObject_SIZE(tp)); |
Tim Peters | fa8efab | 2002-04-28 01:57:25 +0000 | [diff] [blame] | 1271 | if (op != NULL) |
| 1272 | op = PyObject_INIT(op, tp); |
| 1273 | return op; |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1274 | } |
| 1275 | |
| 1276 | PyVarObject * |
Tim Peters | 6d483d3 | 2001-10-06 21:27:34 +0000 | [diff] [blame] | 1277 | _PyObject_GC_NewVar(PyTypeObject *tp, int nitems) |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1278 | { |
Neil Schemenauer | fec4eb1 | 2002-04-12 02:41:03 +0000 | [diff] [blame] | 1279 | const size_t size = _PyObject_VAR_SIZE(tp, nitems); |
| 1280 | PyVarObject *op = (PyVarObject *) _PyObject_GC_Malloc(size); |
Tim Peters | fa8efab | 2002-04-28 01:57:25 +0000 | [diff] [blame] | 1281 | if (op != NULL) |
| 1282 | op = PyObject_INIT_VAR(op, tp, nitems); |
| 1283 | return op; |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1284 | } |
| 1285 | |
| 1286 | PyVarObject * |
Tim Peters | 6d483d3 | 2001-10-06 21:27:34 +0000 | [diff] [blame] | 1287 | _PyObject_GC_Resize(PyVarObject *op, int nitems) |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1288 | { |
Tim Peters | f2a67da | 2001-10-07 03:54:51 +0000 | [diff] [blame] | 1289 | const size_t basicsize = _PyObject_VAR_SIZE(op->ob_type, nitems); |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1290 | PyGC_Head *g = AS_GC(op); |
Neil Schemenauer | fec4eb1 | 2002-04-12 02:41:03 +0000 | [diff] [blame] | 1291 | g = PyObject_REALLOC(g, sizeof(PyGC_Head) + basicsize); |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1292 | if (g == NULL) |
| 1293 | return (PyVarObject *)PyErr_NoMemory(); |
| 1294 | op = (PyVarObject *) FROM_GC(g); |
Tim Peters | 6d483d3 | 2001-10-06 21:27:34 +0000 | [diff] [blame] | 1295 | op->ob_size = nitems; |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1296 | return op; |
| 1297 | } |
| 1298 | |
| 1299 | void |
Neil Schemenauer | fec4eb1 | 2002-04-12 02:41:03 +0000 | [diff] [blame] | 1300 | PyObject_GC_Del(void *op) |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1301 | { |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1302 | PyGC_Head *g = AS_GC(op); |
Neil Schemenauer | a2b11ec | 2002-05-21 15:53:24 +0000 | [diff] [blame] | 1303 | if (IS_TRACKED(op)) |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1304 | gc_list_remove(g); |
Neil Schemenauer | 2880ae5 | 2002-05-04 05:35:20 +0000 | [diff] [blame] | 1305 | if (generations[0].count > 0) { |
| 1306 | generations[0].count--; |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1307 | } |
Neil Schemenauer | fec4eb1 | 2002-04-12 02:41:03 +0000 | [diff] [blame] | 1308 | PyObject_FREE(g); |
Neil Schemenauer | 43411b5 | 2001-08-30 00:05:51 +0000 | [diff] [blame] | 1309 | } |
| 1310 | |
Neil Schemenauer | fec4eb1 | 2002-04-12 02:41:03 +0000 | [diff] [blame] | 1311 | /* for binary compatibility with 2.2 */ |
| 1312 | #undef _PyObject_GC_Del |
| 1313 | void |
| 1314 | _PyObject_GC_Del(PyObject *op) |
| 1315 | { |
| 1316 | PyObject_GC_Del(op); |
| 1317 | } |