/***************************************************************************** Copyright (c) 2001, 2002 Zope Corporation and Contributors. All Rights Reserved. This software is subject to the provisions of the Zope Public License, Version 2.0 (ZPL). A copy of the ZPL should accompany this distribution. THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE ****************************************************************************/ /* Objects are stored under three different regimes: Regime 1: Persistent Classes Persistent Classes are part of ZClasses. They are stored in the self->data dictionary, and are never garbage collected. The klass_items() method returns a sequence of (oid,object) tuples for every Persistent Class, which should make it possible to implement garbage collection in Python if necessary. Regime 2: Ghost Objects There is no benefit to keeping a ghost object which has no external references, therefore a weak reference scheme is used to ensure that ghost objects are removed from memory as soon as possible, when the last external reference is lost. Ghost objects are stored in the self->data dictionary. Normally a dictionary keeps a strong reference on its values, however this reference count is 'stolen'. This weak reference scheme leaves a dangling reference, in the dictionary, when the last external reference is lost. To clean up this dangling reference the persistent object dealloc function calls self->cache->_oid_unreferenced(self->oid). The cache looks up the oid in the dictionary, ensures it points to an object whose reference count is zero, then removes it from the dictionary. Before removing the object from the dictionary it must temporarily resurrect the object in much the same way that class instances are resurrected before their __del__ is called. Since ghost objects are stored under a different regime to non-ghost objects, an extra ghostify function in cPersistenceAPI replaces self->state=GHOST_STATE assignments that were common in other persistent classes (such as BTrees). Regime 3: Non-Ghost Objects Non-ghost objects are stored in two data structures: the dictionary mapping oids to objects and a doubly-linked list that encodes the order in which the objects were accessed. The dictionary reference is borrowed, as it is for ghosts. The list reference is a new reference; the list stores recently used objects, even if they are otherwise unreferenced, to avoid loading the object from the database again. The doubly-link-list nodes contain next and previous pointers linking together the cache and all non-ghost persistent objects. The node embedded in the cache is the home position. On every attribute access a non-ghost object will relink itself just behind the home position in the ring. Objects accessed least recently will eventually find themselves positioned after the home position. Occasionally other nodes are temporarily inserted in the ring as position markers. The cache contains a ring_lock flag which must be set and unset before and after doing so. Only if the flag is unset can the cache assume that all nodes are either his own home node, or nodes from persistent objects. This assumption is useful during the garbage collection process. The number of non-ghost objects is counted in self->non_ghost_count. The garbage collection process consists of traversing the ring, and deactivating (that is, turning into a ghost) every object until self->non_ghost_count is down to the target size, or until it reaches the home position again. Note that objects in the sticky or changed states are still kept in the ring, however they can not be deactivated. The garbage collection process must skip such objects, rather than deactivating them. */ static char cPickleCache_doc_string[] = "Defines the PickleCache used by ZODB Connection objects.\n" "\n" "$Id: cPickleCache.c,v 1.85 2003/05/30 19:20:55 jeremy Exp $\n"; #define ASSIGN(V,E) {PyObject *__e; __e=(E); Py_XDECREF(V); (V)=__e;} #define UNLESS(E) if(!(E)) #define UNLESS_ASSIGN(V,E) ASSIGN(V,E) UNLESS(V) #define OBJECT(O) ((PyObject*)O) #define DONT_USE_CPERSISTENCECAPI #include "cPersistence.h" #include <time.h> #include <stddef.h> #undef Py_FindMethod static PyObject *py__p_oid, *py_reload, *py__p_jar, *py__p_changed; static cPersistenceCAPIstruct *capi; /* Do we want 'engine noise'.... abstract debugging output useful for visualizing cache behavior */ #if 0 #define ENGINE_NOISE(A) printf(A) #else #define ENGINE_NOISE(A) ((void)A) #endif /* This object is the pickle cache. The CACHE_HEAD macro guarantees that layout of this struct is the same as the start of ccobject_head in cPersistence.c */ typedef struct { CACHE_HEAD int klass_count; /* count of persistent classes */ PyObject *data; /* oid -> object dict */ PyObject *jar; /* Connection object */ PyObject *setklassstate; /* ??? */ int cache_size; /* target number of items in cache */ /* Most of the time the ring contains only: * many nodes corresponding to persistent objects * one 'home' node from the cache. In some cases it is handy to temporarily add other types of node into the ring as placeholders. 'ring_lock' is a boolean indicating that someone has already done this. Currently this is only used by the garbage collection code. */ int ring_lock; /* 'cache_drain_resistance' controls how quickly the cache size will drop when it is smaller than the configured size. A value of zero means it will not drop below the configured size (suitable for most caches). Otherwise, it will remove cache_non_ghost_count/cache_drain_resistance items from the cache every time (suitable for rarely used caches, such as those associated with Zope versions. */ int cache_drain_resistance; } ccobject; static int cc_ass_sub(ccobject *self, PyObject *key, PyObject *v); /* ---------------------------------------------------------------- */ #define OBJECT_FROM_RING(SELF, HERE, CTX) \ ((cPersistentObject *)(((char *)here) - offsetof(cPersistentObject, ring))) static int scan_gc_items(ccobject *self,int target) { /* This function must only be called with the ring lock held, because it places a non-object placeholder in the ring. */ cPersistentObject *object; int error; CPersistentRing placeholder; CPersistentRing *here = self->ring_home.next; /* Scan through the ring until we either find the ring_home (i.e. start * of the ring, or we've ghosted enough objects to reach the target * size. */ while (1) { /* back to the home position. stop looking */ if (here == &self->ring_home) return 0; /* At this point we know that the ring only contains nodes from persistent objects, plus our own home node. We know this because the ring lock is held. We can safely assume the current ring node is a persistent object now we know it is not the home */ object = OBJECT_FROM_RING(self, here, "scan_gc_items"); if (!object) return -1; /* we are small enough */ if (self->non_ghost_count <= target) return 0; else if (object->state == cPersistent_UPTODATE_STATE) { /* deactivate it. This is the main memory saver. */ /* Add a placeholder; a dummy node in the ring. We need to do this to mark our position in the ring. It is possible that the PyObject_SetAttr() call below will invoke an __setattr__() hook in Python. If it does, another thread might run; if that thread accesses a persistent object and moves it to the head of the ring, it might cause the gc scan to start working from the head of the list. */ placeholder.next = here->next; placeholder.prev = here; here->next->prev = &placeholder; here->next = &placeholder; ENGINE_NOISE("G"); /* In Python, "obj._p_changed = None" spells, ghostify */ error = PyObject_SetAttr((PyObject *)object, py__p_changed, Py_None); /* unlink the placeholder */ placeholder.next->prev = placeholder.prev; placeholder.prev->next = placeholder.next; here = placeholder.next; if (error) return -1; /* problem */ } else { ENGINE_NOISE("."); here = here->next; } } } static PyObject * lockgc(ccobject *self, int target_size) { /* This is thread-safe because of the GIL, and there's nothing * in between checking the ring_lock and acquiring it that calls back * into Python. */ if (self->ring_lock) { Py_INCREF(Py_None); return Py_None; } ENGINE_NOISE("<"); self->ring_lock = 1; if (scan_gc_items(self, target_size)) { self->ring_lock = 0; return NULL; } self->ring_lock = 0; ENGINE_NOISE(">\n"); Py_INCREF(Py_None); return Py_None; } static PyObject * cc_incrgc(ccobject *self, PyObject *args) { int n = 1; int starting_size = self->non_ghost_count; int target_size = self->cache_size; if (self->cache_drain_resistance >= 1) { /* This cache will gradually drain down to a small size. Check a (small) number of objects proportional to the current size */ int target_size_2 = (starting_size - 1 - starting_size / self->cache_drain_resistance); if (target_size_2 < target_size) target_size = target_size_2; } if (!PyArg_ParseTuple(args, "|i:incrgc", &n)) return NULL; return lockgc(self, target_size); } static PyObject * cc_full_sweep(ccobject *self, PyObject *args) { int dt = 0; if (!PyArg_ParseTuple(args, "|i:full_sweep", &dt)) return NULL; if (dt == 0) return lockgc(self, 0); else return cc_incrgc(self, args); } static PyObject * cc_minimize(ccobject *self, PyObject *args) { int ignored; if (!PyArg_ParseTuple(args, "|i:minimize", &ignored)) return NULL; return lockgc(self, 0); } static void _invalidate(ccobject *self, PyObject *key) { PyObject *v = PyDict_GetItem(self->data, key); if (!v) return; if (PyExtensionClass_Check(v)) { if (v->ob_refcnt <= 1) { self->klass_count--; if (PyDict_DelItem(self->data, key) < 0) PyErr_Clear(); } else { v = PyObject_CallFunction(self->setklassstate, "O", v); if (v) Py_DECREF(v); else PyErr_Clear(); } } else { if (PyObject_DelAttr(v, py__p_changed) < 0) PyErr_Clear(); } } static PyObject * cc_invalidate(ccobject *self, PyObject *args) { PyObject *inv, *key, *v; int i = 0; if (PyArg_ParseTuple(args, "O!", &PyDict_Type, &inv)) { while (PyDict_Next(inv, &i, &key, &v)) _invalidate(self, key); PyDict_Clear(inv); } else { PyErr_Clear(); if (!PyArg_ParseTuple(args, "O:invalidate", &inv)) return NULL; if (PyString_Check(inv)) _invalidate(self, inv); else { int l; PyErr_Clear(); l = PyObject_Length(inv); if (l < 0) return NULL; for (i=l; --i >= 0; ) { key = PySequence_GetItem(inv, i); if (!key) return NULL; _invalidate(self, key); Py_DECREF(key); } /* XXX Do we really want to modify the input? */ PySequence_DelSlice(inv, 0, l); } } Py_INCREF(Py_None); return Py_None; } static PyObject * cc_get(ccobject *self, PyObject *args) { PyObject *r, *key, *d = NULL; if (!PyArg_ParseTuple(args, "O|O:get", &key, &d)) return NULL; r = PyDict_GetItem(self->data, key); if (!r) { if (d) { r = d; } else { PyErr_SetObject(PyExc_KeyError, key); return NULL; } } Py_INCREF(r); return r; } static PyObject * cc_klass_items(ccobject *self, PyObject *args) { PyObject *l,*k,*v; int p = 0; if (!PyArg_ParseTuple(args, ":klass_items")) return NULL; l = PyList_New(PyDict_Size(self->data)); if (l == NULL) return NULL; while (PyDict_Next(self->data, &p, &k, &v)) { if(PyExtensionClass_Check(v)) { v = Py_BuildValue("OO", k, v); if (v == NULL) { Py_DECREF(l); return NULL; } if (PyList_Append(l, v) < 0) { Py_DECREF(v); Py_DECREF(l); return NULL; } Py_DECREF(v); } } return l; } static PyObject * cc_lru_items(ccobject *self, PyObject *args) { PyObject *l; CPersistentRing *here; if (!PyArg_ParseTuple(args, ":lru_items")) return NULL; if (self->ring_lock) { /* When the ring lock is held, we have no way of know which ring nodes belong to persistent objects, and which a placeholders. */ PyErr_SetString(PyExc_ValueError, ".lru_items() is unavailable during garbage collection"); return NULL; } l = PyList_New(0); if (l == NULL) return NULL; here = self->ring_home.next; while (here != &self->ring_home) { PyObject *v; cPersistentObject *object = OBJECT_FROM_RING(self, here, "cc_items"); if (object == NULL) { Py_DECREF(l); return NULL; } v = Py_BuildValue("OO", object->oid, object); if (v == NULL) { Py_DECREF(l); return NULL; } if (PyList_Append(l, v) < 0) { Py_DECREF(v); Py_DECREF(l); return NULL; } Py_DECREF(v); here = here->next; } return l; } /* Be very careful about calling clear(). It removes all non-ghost objects from the ring without otherwise removing them from the cache. The method should only be called after the cache is no longer in use. */ static PyObject * cc_clear(ccobject *self, PyObject *args) { CPersistentRing *here; if (!PyArg_ParseTuple(args, ":clear")) return NULL; if (self->ring_lock) { /* When the ring lock is held, we have no way of know which ring nodes belong to persistent objects, and which a placeholders. */ PyErr_SetString(PyExc_ValueError, ".lru_items() is unavailable during garbage collection"); return NULL; } self->ring_lock = 1; while ((here = self->ring_home.next) != & self->ring_home) { cPersistentObject *o = OBJECT_FROM_RING(self, here, "clear"); self->non_ghost_count--; o->ring.next->prev = &self->ring_home; self->ring_home.next = o->ring.next; o->ring.next = NULL; o->ring.prev = NULL; Py_DECREF(o); } self->ring_lock = 0; Py_INCREF(Py_None); return Py_None; } static int cc_oid_unreferenced(ccobject *self, PyObject *oid) { /* This is called by the persistent object deallocation function when the reference count on a persistent object reaches zero. We need to fix up our dictionary; its reference is now dangling because we stole its reference count. Be careful to not release the global interpreter lock until this is complete. */ PyObject *v; v = PyDict_GetItem(self->data, oid); if (v == NULL) { PyErr_SetObject(PyExc_KeyError, oid); return -1; } assert(v->ob_refcnt == 0); /* Need to be very hairy here because a dictionary is about to decref an already deleted object. */ #ifdef Py_TRACE_REFS /* This is called from the deallocation function after the interpreter has untracked the reference. Track it again. */ _Py_NewReference(v); /* Don't increment total refcount as a result of the shenanigans played in this function. The _Py_NewReference() call above creates artificial references to v. */ _Py_RefTotal--; assert(v->ob_type); #else Py_INCREF(v); #endif assert(v->ob_refcnt == 1); /* Incremement the refcount again, because delitem is going to DECREF it. If it's refcount reached zero again, we'd call back to the dealloc function that called us. */ Py_INCREF(v); /* XXX Should we call _Py_ForgetReference() on error exit? */ if (PyDict_DelItem(self->data, oid) < 0) return -1; Py_DECREF((ccobject *)((cPersistentObject *)v)->cache); if (v->ob_refcnt != 1) { PyErr_SetString(PyExc_ValueError, "refcount is not 1 after removal from dict"); return -1; } /* Undo the temporary resurrection. Don't DECREF the object, because this function is called from the object's dealloc function. If the refcnt reaches zero, it will all be invoked recursively. */ _Py_ForgetReference(v); return 0; } static PyObject * cc_ringlen(ccobject *self, PyObject *args) { CPersistentRing *here; int c = 0; if (!PyArg_ParseTuple(args, ":ringlen")) return NULL; for (here = self->ring_home.next; here != &self->ring_home; here = here->next) c++; return PyInt_FromLong(c); } static struct PyMethodDef cc_methods[] = { {"lru_items", (PyCFunction)cc_lru_items, METH_VARARGS, "List (oid, object) pairs from the lru list, as 2-tuples.\n" }, {"klass_items", (PyCFunction)cc_klass_items, METH_VARARGS, "List (oid, object) pairs of cached persistent classes.\n" }, {"full_sweep", (PyCFunction)cc_full_sweep, METH_VARARGS, "full_sweep([age]) -- Perform a full sweep of the cache\n\n" "Supported for backwards compatibility. If the age argument is 0,\n" "behaves like minimize(). Otherwise, behaves like incrgc()." }, {"minimize", (PyCFunction)cc_minimize, METH_VARARGS, "minimize([ignored]) -- Remove as many objects as possible\n\n" "Ghostify all objects that are not modified. Takes an optional\n" "argument, but ignores it." }, {"incrgc", (PyCFunction)cc_incrgc, METH_VARARGS, "incrgc([n]) -- Perform incremental garbage collection\n\n" "Some other implementations support an optional parameter 'n' which\n" "indicates a repetition count; this value is ignored.\n"}, {"invalidate", (PyCFunction)cc_invalidate, METH_VARARGS, "invalidate(oids) -- invalidate one, many, or all ids"}, {"get", (PyCFunction)cc_get, METH_VARARGS, "get(key [, default]) -- get an item, or a default"}, {"ringlen", (PyCFunction)cc_ringlen, METH_VARARGS, "ringlen() -- Returns number of non-ghost items in cache."}, {"clear", (PyCFunction)cc_clear, METH_VARARGS, "clear() -- remove all objects from the cache"}, {NULL, NULL} /* sentinel */ }; static void cc_dealloc(ccobject *self) { Py_XDECREF(self->data); Py_XDECREF(self->jar); Py_XDECREF(self->setklassstate); PyMem_DEL(self); } static PyObject * cc_getattr(ccobject *self, char *name) { if(*name=='c') { if(strcmp(name,"cache_age")==0) return PyInt_FromLong(0); /* this cache does not use this value */ if(strcmp(name,"cache_size")==0) return PyInt_FromLong(self->cache_size); if(strcmp(name,"cache_drain_resistance")==0) return PyInt_FromLong(self->cache_drain_resistance); if(strcmp(name,"cache_non_ghost_count")==0) return PyInt_FromLong(self->non_ghost_count); if(strcmp(name,"cache_klass_count")==0) return PyInt_FromLong(self->klass_count); if(strcmp(name,"cache_data")==0) { /* now a copy of our data; the ring is too fragile */ return PyDict_Copy(self->data); } } if (strcmp(name, "items") == 0) return PyObject_GetAttrString(self->data, name); return Py_FindMethod(cc_methods, (PyObject *)self, name); } static int cc_setattr(ccobject *self, char *name, PyObject *value) { if(value) { int v; if(strcmp(name,"cache_age")==0) { /* this cache doesnt use the age */ return 0; } if(strcmp(name,"cache_size")==0) { UNLESS(PyArg_Parse(value,"i",&v)) return -1; self->cache_size=v; return 0; } if(strcmp(name,"cache_drain_resistance")==0) { UNLESS(PyArg_Parse(value,"i",&v)) return -1; self->cache_drain_resistance=v; return 0; } } PyErr_SetString(PyExc_AttributeError, name); return -1; } static int cc_length(ccobject *self) { return PyObject_Length(self->data); } static PyObject * cc_subscript(ccobject *self, PyObject *key) { PyObject *r; r = PyDict_GetItem(self->data, key); if (r == NULL) { PyErr_SetObject(PyExc_KeyError, key); return NULL; } Py_INCREF(r); return r; } static int cc_add_item(ccobject *self, PyObject *key, PyObject *v) { int result; PyObject *oid, *object_again, *jar; cPersistentObject *p; if (PyExtensionClass_Check(v)) { /* Its a persistent class, such as a ZClass. Thats ok. */ } else if( PyExtensionInstance_Check(v) && (((PyExtensionClass*)(v->ob_type))->class_flags & PERSISTENT_TYPE_FLAG) && (v->ob_type->tp_basicsize >= sizeof(cPersistentObject)) ) { /* Its and instance of a persistent class, (ie Python classeses that derive from Persistence.Persistent, BTrees, etc). Thats ok. */ } else { PyErr_SetString(PyExc_TypeError, "Cache values must be persistent objects."); return -1; } /* Can't access v->oid directly because the object might be a * persistent class. */ oid = PyObject_GetAttr(v, py__p_oid); if (oid == NULL) return -1; if (!PyString_Check(oid)) { PyErr_Format(PyExc_TypeError, "Cached object oid must be a string, not a %s", oid->ob_type->tp_name); return -1; } /* we know they are both strings. * now check if they are the same string. */ result = PyObject_Compare(key, oid); if (PyErr_Occurred()) { Py_DECREF(oid); return -1; } Py_DECREF(oid); if (result) { PyErr_SetString(PyExc_ValueError, "Cache key does not match oid"); return -1; } /* useful sanity check, but not strictly an invariant of this class */ jar = PyObject_GetAttr(v, py__p_jar); if (jar == NULL) return -1; if (jar==Py_None) { Py_DECREF(jar); PyErr_SetString(PyExc_ValueError, "Cached object jar missing"); return -1; } Py_DECREF(jar); object_again = PyDict_GetItem(self->data, key); if (object_again) { if (object_again != v) { PyErr_SetString(PyExc_ValueError, "Can not re-register object under a different oid"); return -1; } else { /* re-register under the same oid - no work needed */ return 0; } } if (PyExtensionClass_Check(v)) { if (PyDict_SetItem(self->data, key, v) < 0) return -1; self->klass_count++; return 0; } else { PerCache *cache = ((cPersistentObject *)v)->cache; if (cache) { if (cache != (PerCache *)self) /* This object is already in a different cache. */ PyErr_SetString(PyExc_ValueError, "Cache values may only be in one cache."); return -1; } /* else: This object is already one of ours, which is ok. It would be very strange if someone was trying to register the same object under a different key. */ } if (PyDict_SetItem(self->data, key, v) < 0) return -1; /* the dict should have a borrowed reference */ Py_DECREF(v); p = (cPersistentObject *)v; Py_INCREF(self); p->cache = (PerCache *)self; if (p->state >= 0) { /* insert this non-ghost object into the ring just behind the home position. */ self->non_ghost_count++; p->ring.next = &self->ring_home; p->ring.prev = self->ring_home.prev; self->ring_home.prev->next = &p->ring; self->ring_home.prev = &p->ring; /* this list should have a new reference to the object */ Py_INCREF(v); } return 0; } static int cc_del_item(ccobject *self, PyObject *key) { PyObject *v; cPersistentObject *p; /* unlink this item from the ring */ v = PyDict_GetItem(self->data, key); if (v == NULL) return -1; if (PyExtensionClass_Check(v)) { self->klass_count--; } else { p = (cPersistentObject *)v; if (p->state >= 0) { self->non_ghost_count--; p->ring.next->prev = p->ring.prev; p->ring.prev->next = p->ring.next; p->ring.prev = NULL; p->ring.next = NULL; /* The DelItem below will account for the reference held by the list. */ } else { /* This is a ghost object, so we havent kept a reference count on it. For it have stayed alive this long someone else must be keeping a reference to it. Therefore we need to temporarily give it back a reference count before calling DelItem below */ Py_INCREF(v); } Py_DECREF((PyObject *)p->cache); p->cache = NULL; } if (PyDict_DelItem(self->data, key) < 0) { PyErr_SetString(PyExc_RuntimeError, "unexpectedly couldn't remove key in cc_ass_sub"); return -1; } return 0; } static int cc_ass_sub(ccobject *self, PyObject *key, PyObject *v) { if (!PyString_Check(key)) { PyErr_Format(PyExc_TypeError, "cPickleCache key must be a string, not a %s", key->ob_type->tp_name); return -1; } if (v) return cc_add_item(self, key, v); else return cc_del_item(self, key); } static PyMappingMethods cc_as_mapping = { (inquiry)cc_length, /*mp_length*/ (binaryfunc)cc_subscript, /*mp_subscript*/ (objobjargproc)cc_ass_sub, /*mp_ass_subscript*/ }; static PyTypeObject Cctype = { PyObject_HEAD_INIT(NULL) 0, /*ob_size*/ "cPickleCache", /*tp_name*/ sizeof(ccobject), /*tp_basicsize*/ 0, /*tp_itemsize*/ /* methods */ (destructor)cc_dealloc, /*tp_dealloc*/ (printfunc)0, /*tp_print*/ (getattrfunc)cc_getattr, /*tp_getattr*/ (setattrfunc)cc_setattr, /*tp_setattr*/ (cmpfunc)0, /*tp_compare*/ (reprfunc)0, /*tp_repr*/ 0, /*tp_as_number*/ 0, /*tp_as_sequence*/ &cc_as_mapping, /*tp_as_mapping*/ (hashfunc)0, /*tp_hash*/ (ternaryfunc)0, /*tp_call*/ (reprfunc)0, /*tp_str*/ }; static ccobject * newccobject(PyObject *jar, int cache_size) { ccobject *self; self = PyObject_NEW(ccobject, &Cctype); if (self == NULL) return NULL; self->setklassstate = self->jar = NULL; self->data = PyDict_New(); if (self->data == NULL) { Py_DECREF(self); return NULL; } self->setklassstate = PyObject_GetAttrString(jar, "setklassstate"); if (self->setklassstate == NULL) { Py_DECREF(self); return NULL; } self->jar = jar; Py_INCREF(jar); self->cache_size = cache_size; self->non_ghost_count = 0; self->klass_count = 0; self->cache_drain_resistance = 0; self->ring_lock = 0; self->ring_home.next = &self->ring_home; self->ring_home.prev = &self->ring_home; return self; } static PyObject * cCM_new(PyObject *self, PyObject *args) { int cache_size=100; PyObject *jar; if (!PyArg_ParseTuple(args, "O|i", &jar, &cache_size)) return NULL; return (PyObject*)newccobject(jar, cache_size); } static struct PyMethodDef cCM_methods[] = { {"PickleCache", (PyCFunction)cCM_new, METH_VARARGS}, {NULL, NULL} /* sentinel */ }; void initcPickleCache(void) { PyObject *m, *d; Cctype.ob_type = &PyType_Type; if (!ExtensionClassImported) return; capi = (cPersistenceCAPIstruct *)PyCObject_Import("cPersistence", "CAPI"); if (!capi) return; capi->percachedel = (percachedelfunc)cc_oid_unreferenced; m = Py_InitModule4("cPickleCache", cCM_methods, cPickleCache_doc_string, (PyObject*)NULL, PYTHON_API_VERSION); py_reload = PyString_InternFromString("reload"); py__p_jar = PyString_InternFromString("_p_jar"); py__p_changed = PyString_InternFromString("_p_changed"); py__p_oid = PyString_InternFromString("_p_oid"); d = PyModule_GetDict(m); PyDict_SetItemString(d, "cache_variant", PyString_FromString("stiff/c")); }