Guido van Rossum | a330996 | 1993-07-28 09:05:47 +0000 | [diff] [blame] | 1 | #ifndef Py_OBJECT_H |
| 2 | #define Py_OBJECT_H |
| 3 | #ifdef __cplusplus |
| 4 | extern "C" { |
| 5 | #endif |
| 6 | |
Guido van Rossum | f70e43a | 1991-02-19 12:39:46 +0000 | [diff] [blame] | 7 | |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 8 | /* Object and type object interface */ |
| 9 | |
| 10 | /* |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 11 | Objects are structures allocated on the heap. Special rules apply to |
| 12 | the use of objects to ensure they are properly garbage-collected. |
| 13 | Objects are never allocated statically or on the stack; they must be |
| 14 | accessed through special macros and functions only. (Type objects are |
| 15 | exceptions to the first rule; the standard types are represented by |
Tim Peters | 4be93d0 | 2002-07-07 19:59:50 +0000 | [diff] [blame] | 16 | statically initialized type objects, although work on type/class unification |
| 17 | for Python 2.2 made it possible to have heap-allocated type objects too). |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 18 | |
| 19 | An object has a 'reference count' that is increased or decreased when a |
| 20 | pointer to the object is copied or deleted; when the reference count |
| 21 | reaches zero there are no references to the object left and it can be |
| 22 | removed from the heap. |
| 23 | |
| 24 | An object has a 'type' that determines what it represents and what kind |
| 25 | of data it contains. An object's type is fixed when it is created. |
| 26 | Types themselves are represented as objects; an object contains a |
| 27 | pointer to the corresponding type object. The type itself has a type |
| 28 | pointer pointing to the object representing the type 'type', which |
| 29 | contains a pointer to itself!). |
| 30 | |
| 31 | Objects do not float around in memory; once allocated an object keeps |
| 32 | the same size and address. Objects that must hold variable-size data |
| 33 | can contain pointers to variable-size parts of the object. Not all |
| 34 | objects of the same type have the same size; but the size cannot change |
| 35 | after allocation. (These restrictions are made so a reference to an |
| 36 | object can be simply a pointer -- moving an object would require |
| 37 | updating all the pointers, and changing an object's size would require |
| 38 | moving it if there was another object right next to it.) |
| 39 | |
Guido van Rossum | caa6380 | 1995-01-12 11:45:45 +0000 | [diff] [blame] | 40 | Objects are always accessed through pointers of the type 'PyObject *'. |
| 41 | The type 'PyObject' is a structure that only contains the reference count |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 42 | and the type pointer. The actual memory allocated for an object |
| 43 | contains other data that can only be accessed after casting the pointer |
| 44 | to a pointer to a longer structure type. This longer type must start |
Guido van Rossum | caa6380 | 1995-01-12 11:45:45 +0000 | [diff] [blame] | 45 | with the reference count and type fields; the macro PyObject_HEAD should be |
Thomas Wouters | 7e47402 | 2000-07-16 12:04:32 +0000 | [diff] [blame] | 46 | used for this (to accommodate for future changes). The implementation |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 47 | of a particular object type can cast the object pointer to the proper |
| 48 | type and back. |
| 49 | |
| 50 | A standard interface exists for objects that contain an array of items |
| 51 | whose size is determined when the object is allocated. |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 52 | */ |
| 53 | |
Tim Peters | 3459251 | 2002-07-11 06:23:50 +0000 | [diff] [blame] | 54 | /* Py_DEBUG implies Py_TRACE_REFS. */ |
| 55 | #if defined(Py_DEBUG) && !defined(Py_TRACE_REFS) |
Tim Peters | 4be93d0 | 2002-07-07 19:59:50 +0000 | [diff] [blame] | 56 | #define Py_TRACE_REFS |
Tim Peters | 3459251 | 2002-07-11 06:23:50 +0000 | [diff] [blame] | 57 | #endif |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 58 | |
Tim Peters | 4be93d0 | 2002-07-07 19:59:50 +0000 | [diff] [blame] | 59 | /* Py_TRACE_REFS implies Py_REF_DEBUG. */ |
| 60 | #if defined(Py_TRACE_REFS) && !defined(Py_REF_DEBUG) |
| 61 | #define Py_REF_DEBUG |
| 62 | #endif |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 63 | |
Tim Peters | 4be93d0 | 2002-07-07 19:59:50 +0000 | [diff] [blame] | 64 | #ifdef Py_TRACE_REFS |
| 65 | /* Define pointers to support a doubly-linked list of all live heap objects. */ |
| 66 | #define _PyObject_HEAD_EXTRA \ |
| 67 | struct _object *_ob_next; \ |
| 68 | struct _object *_ob_prev; |
| 69 | |
| 70 | #define _PyObject_EXTRA_INIT 0, 0, |
| 71 | |
| 72 | #else |
| 73 | #define _PyObject_HEAD_EXTRA |
| 74 | #define _PyObject_EXTRA_INIT |
| 75 | #endif |
| 76 | |
| 77 | /* PyObject_HEAD defines the initial segment of every PyObject. */ |
| 78 | #define PyObject_HEAD \ |
| 79 | _PyObject_HEAD_EXTRA \ |
| 80 | int ob_refcnt; \ |
| 81 | struct _typeobject *ob_type; |
| 82 | |
| 83 | #define PyObject_HEAD_INIT(type) \ |
| 84 | _PyObject_EXTRA_INIT \ |
| 85 | 1, type, |
| 86 | |
| 87 | /* PyObject_VAR_HEAD defines the initial segment of all variable-size |
| 88 | * container objects. These end with a declaration of an array with 1 |
| 89 | * element, but enough space is malloc'ed so that the array actually |
| 90 | * has room for ob_size elements. Note that ob_size is an element count, |
| 91 | * not necessarily a byte count. |
| 92 | */ |
| 93 | #define PyObject_VAR_HEAD \ |
| 94 | PyObject_HEAD \ |
Martin v. Löwis | 18e1655 | 2006-02-15 17:27:45 +0000 | [diff] [blame] | 95 | Py_ssize_t ob_size; /* Number of items in variable part */ |
| 96 | #define Py_INVALID_SIZE (Py_ssize_t)-1 |
Tim Peters | 803526b | 2002-07-07 05:13:56 +0000 | [diff] [blame] | 97 | |
Tim Peters | 4be93d0 | 2002-07-07 19:59:50 +0000 | [diff] [blame] | 98 | /* Nothing is actually declared to be a PyObject, but every pointer to |
| 99 | * a Python object can be cast to a PyObject*. This is inheritance built |
| 100 | * by hand. Similarly every pointer to a variable-size Python object can, |
| 101 | * in addition, be cast to PyVarObject*. |
| 102 | */ |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 103 | typedef struct _object { |
Guido van Rossum | caa6380 | 1995-01-12 11:45:45 +0000 | [diff] [blame] | 104 | PyObject_HEAD |
| 105 | } PyObject; |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 106 | |
| 107 | typedef struct { |
Guido van Rossum | caa6380 | 1995-01-12 11:45:45 +0000 | [diff] [blame] | 108 | PyObject_VAR_HEAD |
Guido van Rossum | d0c87ee | 1997-05-15 21:31:03 +0000 | [diff] [blame] | 109 | } PyVarObject; |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 110 | |
| 111 | |
| 112 | /* |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 113 | Type objects contain a string containing the type name (to help somewhat |
Tim Peters | 4be93d0 | 2002-07-07 19:59:50 +0000 | [diff] [blame] | 114 | in debugging), the allocation parameters (see PyObject_New() and |
| 115 | PyObject_NewVar()), |
| 116 | and methods for accessing objects of the type. Methods are optional, a |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 117 | nil pointer meaning that particular kind of access is not available for |
Guido van Rossum | caa6380 | 1995-01-12 11:45:45 +0000 | [diff] [blame] | 118 | this type. The Py_DECREF() macro uses the tp_dealloc method without |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 119 | checking for a nil pointer; it should always be implemented except if |
| 120 | the implementation can guarantee that the reference count will never |
Tim Peters | 4be93d0 | 2002-07-07 19:59:50 +0000 | [diff] [blame] | 121 | reach zero (e.g., for statically allocated type objects). |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 122 | |
| 123 | NB: the methods for certain type groups are now contained in separate |
| 124 | method blocks. |
| 125 | */ |
| 126 | |
Tim Peters | 9ace6bc | 2000-07-08 00:32:04 +0000 | [diff] [blame] | 127 | typedef PyObject * (*unaryfunc)(PyObject *); |
| 128 | typedef PyObject * (*binaryfunc)(PyObject *, PyObject *); |
| 129 | typedef PyObject * (*ternaryfunc)(PyObject *, PyObject *, PyObject *); |
| 130 | typedef int (*inquiry)(PyObject *); |
Martin v. Löwis | 18e1655 | 2006-02-15 17:27:45 +0000 | [diff] [blame] | 131 | typedef Py_ssize_t (*lenfunc)(PyObject *); |
Tim Peters | 9ace6bc | 2000-07-08 00:32:04 +0000 | [diff] [blame] | 132 | typedef int (*coercion)(PyObject **, PyObject **); |
Martin v. Löwis | 18e1655 | 2006-02-15 17:27:45 +0000 | [diff] [blame] | 133 | typedef PyObject *(*intargfunc)(PyObject *, int) Py_DEPRECATED(2.5); |
| 134 | typedef PyObject *(*intintargfunc)(PyObject *, int, int) Py_DEPRECATED(2.5); |
| 135 | typedef PyObject *(*ssizeargfunc)(PyObject *, Py_ssize_t); |
| 136 | typedef PyObject *(*ssizessizeargfunc)(PyObject *, Py_ssize_t, Py_ssize_t); |
Tim Peters | 9ace6bc | 2000-07-08 00:32:04 +0000 | [diff] [blame] | 137 | typedef int(*intobjargproc)(PyObject *, int, PyObject *); |
| 138 | typedef int(*intintobjargproc)(PyObject *, int, int, PyObject *); |
Martin v. Löwis | 18e1655 | 2006-02-15 17:27:45 +0000 | [diff] [blame] | 139 | typedef int(*ssizeobjargproc)(PyObject *, Py_ssize_t, PyObject *); |
| 140 | typedef int(*ssizessizeobjargproc)(PyObject *, Py_ssize_t, Py_ssize_t, PyObject *); |
Tim Peters | 9ace6bc | 2000-07-08 00:32:04 +0000 | [diff] [blame] | 141 | typedef int(*objobjargproc)(PyObject *, PyObject *, PyObject *); |
Martin v. Löwis | 18e1655 | 2006-02-15 17:27:45 +0000 | [diff] [blame] | 142 | |
| 143 | /* int-based buffer interface */ |
Tim Peters | 9ace6bc | 2000-07-08 00:32:04 +0000 | [diff] [blame] | 144 | typedef int (*getreadbufferproc)(PyObject *, int, void **); |
| 145 | typedef int (*getwritebufferproc)(PyObject *, int, void **); |
| 146 | typedef int (*getsegcountproc)(PyObject *, int *); |
| 147 | typedef int (*getcharbufferproc)(PyObject *, int, const char **); |
Martin v. Löwis | 18e1655 | 2006-02-15 17:27:45 +0000 | [diff] [blame] | 148 | /* ssize_t-based buffer interface */ |
| 149 | typedef Py_ssize_t (*readbufferproc)(PyObject *, Py_ssize_t, void **); |
| 150 | typedef Py_ssize_t (*writebufferproc)(PyObject *, Py_ssize_t, void **); |
| 151 | typedef Py_ssize_t (*segcountproc)(PyObject *, Py_ssize_t *); |
| 152 | typedef Py_ssize_t (*charbufferproc)(PyObject *, Py_ssize_t, const char **); |
| 153 | |
Tim Peters | 9ace6bc | 2000-07-08 00:32:04 +0000 | [diff] [blame] | 154 | typedef int (*objobjproc)(PyObject *, PyObject *); |
| 155 | typedef int (*visitproc)(PyObject *, void *); |
| 156 | typedef int (*traverseproc)(PyObject *, visitproc, void *); |
Guido van Rossum | b6775db | 1994-08-01 11:34:53 +0000 | [diff] [blame] | 157 | |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 158 | typedef struct { |
Guido van Rossum | 5f284ce | 2001-01-17 15:20:39 +0000 | [diff] [blame] | 159 | /* For numbers without flag bit Py_TPFLAGS_CHECKTYPES set, all |
| 160 | arguments are guaranteed to be of the object's type (modulo |
Tim Peters | 4be93d0 | 2002-07-07 19:59:50 +0000 | [diff] [blame] | 161 | coercion hacks -- i.e. if the type's coercion function |
Guido van Rossum | 5f284ce | 2001-01-17 15:20:39 +0000 | [diff] [blame] | 162 | returns other types, then these are allowed as well). Numbers that |
| 163 | have the Py_TPFLAGS_CHECKTYPES flag bit set should check *both* |
| 164 | arguments for proper type and implement the necessary conversions |
| 165 | in the slot functions themselves. */ |
Neil Schemenauer | a7ed694 | 2001-01-04 01:31:50 +0000 | [diff] [blame] | 166 | |
Guido van Rossum | b6775db | 1994-08-01 11:34:53 +0000 | [diff] [blame] | 167 | binaryfunc nb_add; |
| 168 | binaryfunc nb_subtract; |
| 169 | binaryfunc nb_multiply; |
| 170 | binaryfunc nb_divide; |
| 171 | binaryfunc nb_remainder; |
| 172 | binaryfunc nb_divmod; |
Guido van Rossum | 75abc63 | 1994-08-09 13:21:54 +0000 | [diff] [blame] | 173 | ternaryfunc nb_power; |
Guido van Rossum | b6775db | 1994-08-01 11:34:53 +0000 | [diff] [blame] | 174 | unaryfunc nb_negative; |
| 175 | unaryfunc nb_positive; |
| 176 | unaryfunc nb_absolute; |
| 177 | inquiry nb_nonzero; |
| 178 | unaryfunc nb_invert; |
| 179 | binaryfunc nb_lshift; |
| 180 | binaryfunc nb_rshift; |
| 181 | binaryfunc nb_and; |
| 182 | binaryfunc nb_xor; |
| 183 | binaryfunc nb_or; |
| 184 | coercion nb_coerce; |
| 185 | unaryfunc nb_int; |
| 186 | unaryfunc nb_long; |
| 187 | unaryfunc nb_float; |
| 188 | unaryfunc nb_oct; |
| 189 | unaryfunc nb_hex; |
Fred Drake | d55657b | 2001-08-15 18:32:33 +0000 | [diff] [blame] | 190 | /* Added in release 2.0 */ |
Thomas Wouters | dd8dbdb | 2000-08-24 20:09:45 +0000 | [diff] [blame] | 191 | binaryfunc nb_inplace_add; |
| 192 | binaryfunc nb_inplace_subtract; |
| 193 | binaryfunc nb_inplace_multiply; |
| 194 | binaryfunc nb_inplace_divide; |
| 195 | binaryfunc nb_inplace_remainder; |
| 196 | ternaryfunc nb_inplace_power; |
| 197 | binaryfunc nb_inplace_lshift; |
| 198 | binaryfunc nb_inplace_rshift; |
| 199 | binaryfunc nb_inplace_and; |
| 200 | binaryfunc nb_inplace_xor; |
| 201 | binaryfunc nb_inplace_or; |
Guido van Rossum | 4668b00 | 2001-08-08 05:00:18 +0000 | [diff] [blame] | 202 | |
Fred Drake | d55657b | 2001-08-15 18:32:33 +0000 | [diff] [blame] | 203 | /* Added in release 2.2 */ |
Guido van Rossum | 4668b00 | 2001-08-08 05:00:18 +0000 | [diff] [blame] | 204 | /* The following require the Py_TPFLAGS_HAVE_CLASS flag */ |
| 205 | binaryfunc nb_floor_divide; |
| 206 | binaryfunc nb_true_divide; |
| 207 | binaryfunc nb_inplace_floor_divide; |
| 208 | binaryfunc nb_inplace_true_divide; |
Guido van Rossum | caa6380 | 1995-01-12 11:45:45 +0000 | [diff] [blame] | 209 | } PyNumberMethods; |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 210 | |
| 211 | typedef struct { |
Martin v. Löwis | 18e1655 | 2006-02-15 17:27:45 +0000 | [diff] [blame] | 212 | lenfunc sq_length; |
Guido van Rossum | b6775db | 1994-08-01 11:34:53 +0000 | [diff] [blame] | 213 | binaryfunc sq_concat; |
Martin v. Löwis | 18e1655 | 2006-02-15 17:27:45 +0000 | [diff] [blame] | 214 | ssizeargfunc sq_repeat; |
| 215 | ssizeargfunc sq_item; |
| 216 | ssizessizeargfunc sq_slice; |
| 217 | ssizeobjargproc sq_ass_item; |
| 218 | ssizessizeobjargproc sq_ass_slice; |
Guido van Rossum | cecb27a | 2000-02-28 15:00:40 +0000 | [diff] [blame] | 219 | objobjproc sq_contains; |
Fred Drake | d55657b | 2001-08-15 18:32:33 +0000 | [diff] [blame] | 220 | /* Added in release 2.0 */ |
Thomas Wouters | dd8dbdb | 2000-08-24 20:09:45 +0000 | [diff] [blame] | 221 | binaryfunc sq_inplace_concat; |
Martin v. Löwis | 18e1655 | 2006-02-15 17:27:45 +0000 | [diff] [blame] | 222 | ssizeargfunc sq_inplace_repeat; |
Guido van Rossum | caa6380 | 1995-01-12 11:45:45 +0000 | [diff] [blame] | 223 | } PySequenceMethods; |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 224 | |
| 225 | typedef struct { |
Martin v. Löwis | 18e1655 | 2006-02-15 17:27:45 +0000 | [diff] [blame] | 226 | lenfunc mp_length; |
Guido van Rossum | b6775db | 1994-08-01 11:34:53 +0000 | [diff] [blame] | 227 | binaryfunc mp_subscript; |
| 228 | objobjargproc mp_ass_subscript; |
Guido van Rossum | caa6380 | 1995-01-12 11:45:45 +0000 | [diff] [blame] | 229 | } PyMappingMethods; |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 230 | |
Guido van Rossum | fdf95dd | 1997-05-05 22:15:02 +0000 | [diff] [blame] | 231 | typedef struct { |
Martin v. Löwis | 18e1655 | 2006-02-15 17:27:45 +0000 | [diff] [blame] | 232 | readbufferproc bf_getreadbuffer; |
| 233 | writebufferproc bf_getwritebuffer; |
| 234 | segcountproc bf_getsegcount; |
| 235 | charbufferproc bf_getcharbuffer; |
Guido van Rossum | fdf95dd | 1997-05-05 22:15:02 +0000 | [diff] [blame] | 236 | } PyBufferProcs; |
Tim Peters | 803526b | 2002-07-07 05:13:56 +0000 | [diff] [blame] | 237 | |
Guido van Rossum | fdf95dd | 1997-05-05 22:15:02 +0000 | [diff] [blame] | 238 | |
Neil Schemenauer | f6d1ea1 | 2002-04-12 01:57:06 +0000 | [diff] [blame] | 239 | typedef void (*freefunc)(void *); |
Tim Peters | 9ace6bc | 2000-07-08 00:32:04 +0000 | [diff] [blame] | 240 | typedef void (*destructor)(PyObject *); |
| 241 | typedef int (*printfunc)(PyObject *, FILE *, int); |
Jeremy Hylton | af68c87 | 2005-12-10 18:50:16 +0000 | [diff] [blame] | 242 | typedef PyObject *(*getattrfunc)(PyObject *, const char *); |
Tim Peters | 9ace6bc | 2000-07-08 00:32:04 +0000 | [diff] [blame] | 243 | typedef PyObject *(*getattrofunc)(PyObject *, PyObject *); |
Jeremy Hylton | af68c87 | 2005-12-10 18:50:16 +0000 | [diff] [blame] | 244 | typedef int (*setattrfunc)(PyObject *, const char *, PyObject *); |
Tim Peters | 9ace6bc | 2000-07-08 00:32:04 +0000 | [diff] [blame] | 245 | typedef int (*setattrofunc)(PyObject *, PyObject *, PyObject *); |
| 246 | typedef int (*cmpfunc)(PyObject *, PyObject *); |
| 247 | typedef PyObject *(*reprfunc)(PyObject *); |
| 248 | typedef long (*hashfunc)(PyObject *); |
Guido van Rossum | 5f284ce | 2001-01-17 15:20:39 +0000 | [diff] [blame] | 249 | typedef PyObject *(*richcmpfunc) (PyObject *, PyObject *, int); |
Guido van Rossum | 59d1d2b | 2001-04-20 19:13:02 +0000 | [diff] [blame] | 250 | typedef PyObject *(*getiterfunc) (PyObject *); |
Guido van Rossum | 213c7a6 | 2001-04-23 14:08:49 +0000 | [diff] [blame] | 251 | typedef PyObject *(*iternextfunc) (PyObject *); |
Tim Peters | 6d6c1a3 | 2001-08-02 04:15:00 +0000 | [diff] [blame] | 252 | typedef PyObject *(*descrgetfunc) (PyObject *, PyObject *, PyObject *); |
| 253 | typedef int (*descrsetfunc) (PyObject *, PyObject *, PyObject *); |
| 254 | typedef int (*initproc)(PyObject *, PyObject *, PyObject *); |
| 255 | typedef PyObject *(*newfunc)(struct _typeobject *, PyObject *, PyObject *); |
Martin v. Löwis | 18e1655 | 2006-02-15 17:27:45 +0000 | [diff] [blame] | 256 | typedef PyObject *(*allocfunc)(struct _typeobject *, Py_ssize_t); |
Guido van Rossum | b6775db | 1994-08-01 11:34:53 +0000 | [diff] [blame] | 257 | |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 258 | typedef struct _typeobject { |
Guido van Rossum | caa6380 | 1995-01-12 11:45:45 +0000 | [diff] [blame] | 259 | PyObject_VAR_HEAD |
Jeremy Hylton | af68c87 | 2005-12-10 18:50:16 +0000 | [diff] [blame] | 260 | const char *tp_name; /* For printing, in format "<module>.<name>" */ |
Martin v. Löwis | 97c65a8 | 2006-02-16 14:24:38 +0000 | [diff] [blame] | 261 | Py_ssize_t tp_basicsize, tp_itemsize; /* For allocation */ |
Tim Peters | 803526b | 2002-07-07 05:13:56 +0000 | [diff] [blame] | 262 | |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 263 | /* Methods to implement standard operations */ |
Tim Peters | 803526b | 2002-07-07 05:13:56 +0000 | [diff] [blame] | 264 | |
Guido van Rossum | b6775db | 1994-08-01 11:34:53 +0000 | [diff] [blame] | 265 | destructor tp_dealloc; |
| 266 | printfunc tp_print; |
| 267 | getattrfunc tp_getattr; |
| 268 | setattrfunc tp_setattr; |
| 269 | cmpfunc tp_compare; |
| 270 | reprfunc tp_repr; |
Tim Peters | 803526b | 2002-07-07 05:13:56 +0000 | [diff] [blame] | 271 | |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 272 | /* Method suites for standard classes */ |
Tim Peters | 803526b | 2002-07-07 05:13:56 +0000 | [diff] [blame] | 273 | |
Guido van Rossum | caa6380 | 1995-01-12 11:45:45 +0000 | [diff] [blame] | 274 | PyNumberMethods *tp_as_number; |
| 275 | PySequenceMethods *tp_as_sequence; |
| 276 | PyMappingMethods *tp_as_mapping; |
Guido van Rossum | 9bfef44 | 1993-03-29 10:43:31 +0000 | [diff] [blame] | 277 | |
Fred Drake | 0e12bcd | 2000-03-21 16:14:47 +0000 | [diff] [blame] | 278 | /* More standard operations (here for binary compatibility) */ |
Guido van Rossum | 9bfef44 | 1993-03-29 10:43:31 +0000 | [diff] [blame] | 279 | |
Guido van Rossum | b6775db | 1994-08-01 11:34:53 +0000 | [diff] [blame] | 280 | hashfunc tp_hash; |
Guido van Rossum | 884afd6 | 1995-07-18 14:21:06 +0000 | [diff] [blame] | 281 | ternaryfunc tp_call; |
Guido van Rossum | 6fde390 | 1995-01-07 10:32:04 +0000 | [diff] [blame] | 282 | reprfunc tp_str; |
Guido van Rossum | 0693dd2 | 1996-08-09 20:48:52 +0000 | [diff] [blame] | 283 | getattrofunc tp_getattro; |
| 284 | setattrofunc tp_setattro; |
Guido van Rossum | 6fde390 | 1995-01-07 10:32:04 +0000 | [diff] [blame] | 285 | |
Guido van Rossum | fdf95dd | 1997-05-05 22:15:02 +0000 | [diff] [blame] | 286 | /* Functions to access object as input/output buffer */ |
| 287 | PyBufferProcs *tp_as_buffer; |
Tim Peters | 803526b | 2002-07-07 05:13:56 +0000 | [diff] [blame] | 288 | |
Guido van Rossum | 36eef3c | 1998-10-08 02:10:56 +0000 | [diff] [blame] | 289 | /* Flags to define presence of optional/expanded features */ |
| 290 | long tp_flags; |
Guido van Rossum | 6fde390 | 1995-01-07 10:32:04 +0000 | [diff] [blame] | 291 | |
Jeremy Hylton | af68c87 | 2005-12-10 18:50:16 +0000 | [diff] [blame] | 292 | const char *tp_doc; /* Documentation string */ |
Guido van Rossum | 6fde390 | 1995-01-07 10:32:04 +0000 | [diff] [blame] | 293 | |
Fred Drake | d55657b | 2001-08-15 18:32:33 +0000 | [diff] [blame] | 294 | /* Assigned meaning in release 2.0 */ |
Jeremy Hylton | 8caad49 | 2000-06-23 14:18:11 +0000 | [diff] [blame] | 295 | /* call function for all accessible objects */ |
| 296 | traverseproc tp_traverse; |
Tim Peters | 803526b | 2002-07-07 05:13:56 +0000 | [diff] [blame] | 297 | |
Jeremy Hylton | 8caad49 | 2000-06-23 14:18:11 +0000 | [diff] [blame] | 298 | /* delete references to contained objects */ |
| 299 | inquiry tp_clear; |
| 300 | |
Fred Drake | d55657b | 2001-08-15 18:32:33 +0000 | [diff] [blame] | 301 | /* Assigned meaning in release 2.1 */ |
Guido van Rossum | 5f284ce | 2001-01-17 15:20:39 +0000 | [diff] [blame] | 302 | /* rich comparisons */ |
| 303 | richcmpfunc tp_richcompare; |
| 304 | |
Fred Drake | 41deb1e | 2001-02-01 05:27:45 +0000 | [diff] [blame] | 305 | /* weak reference enabler */ |
Martin v. Löwis | 97c65a8 | 2006-02-16 14:24:38 +0000 | [diff] [blame] | 306 | Py_ssize_t tp_weaklistoffset; |
Guido van Rossum | a9c2d7a | 1998-04-23 19:16:44 +0000 | [diff] [blame] | 307 | |
Fred Drake | d55657b | 2001-08-15 18:32:33 +0000 | [diff] [blame] | 308 | /* Added in release 2.2 */ |
Guido van Rossum | 59d1d2b | 2001-04-20 19:13:02 +0000 | [diff] [blame] | 309 | /* Iterators */ |
| 310 | getiterfunc tp_iter; |
Guido van Rossum | 213c7a6 | 2001-04-23 14:08:49 +0000 | [diff] [blame] | 311 | iternextfunc tp_iternext; |
Guido van Rossum | 59d1d2b | 2001-04-20 19:13:02 +0000 | [diff] [blame] | 312 | |
Tim Peters | 6d6c1a3 | 2001-08-02 04:15:00 +0000 | [diff] [blame] | 313 | /* Attribute descriptor and subclassing stuff */ |
| 314 | struct PyMethodDef *tp_methods; |
Guido van Rossum | 6f79937 | 2001-09-20 20:46:19 +0000 | [diff] [blame] | 315 | struct PyMemberDef *tp_members; |
Guido van Rossum | 32d34c8 | 2001-09-20 21:45:26 +0000 | [diff] [blame] | 316 | struct PyGetSetDef *tp_getset; |
Tim Peters | 6d6c1a3 | 2001-08-02 04:15:00 +0000 | [diff] [blame] | 317 | struct _typeobject *tp_base; |
| 318 | PyObject *tp_dict; |
| 319 | descrgetfunc tp_descr_get; |
| 320 | descrsetfunc tp_descr_set; |
Martin v. Löwis | 97c65a8 | 2006-02-16 14:24:38 +0000 | [diff] [blame] | 321 | Py_ssize_t tp_dictoffset; |
Tim Peters | 6d6c1a3 | 2001-08-02 04:15:00 +0000 | [diff] [blame] | 322 | initproc tp_init; |
| 323 | allocfunc tp_alloc; |
| 324 | newfunc tp_new; |
Neil Schemenauer | f6d1ea1 | 2002-04-12 01:57:06 +0000 | [diff] [blame] | 325 | freefunc tp_free; /* Low-level free-memory routine */ |
Guido van Rossum | 048eb75 | 2001-10-02 21:24:57 +0000 | [diff] [blame] | 326 | inquiry tp_is_gc; /* For PyObject_IS_GC */ |
Tim Peters | 6d6c1a3 | 2001-08-02 04:15:00 +0000 | [diff] [blame] | 327 | PyObject *tp_bases; |
| 328 | PyObject *tp_mro; /* method resolution order */ |
Guido van Rossum | 687ae00 | 2001-10-15 22:03:32 +0000 | [diff] [blame] | 329 | PyObject *tp_cache; |
Guido van Rossum | 1c45073 | 2001-10-08 15:18:27 +0000 | [diff] [blame] | 330 | PyObject *tp_subclasses; |
| 331 | PyObject *tp_weaklist; |
Guido van Rossum | febd61d | 2002-08-08 20:55:20 +0000 | [diff] [blame] | 332 | destructor tp_del; |
Tim Peters | 6d6c1a3 | 2001-08-02 04:15:00 +0000 | [diff] [blame] | 333 | |
Sjoerd Mullender | a9c3c22 | 1993-10-11 12:54:31 +0000 | [diff] [blame] | 334 | #ifdef COUNT_ALLOCS |
Guido van Rossum | 59d1d2b | 2001-04-20 19:13:02 +0000 | [diff] [blame] | 335 | /* these must be last and never explicitly initialized */ |
Tim Peters | 6d6c1a3 | 2001-08-02 04:15:00 +0000 | [diff] [blame] | 336 | int tp_allocs; |
| 337 | int tp_frees; |
Sjoerd Mullender | a9c3c22 | 1993-10-11 12:54:31 +0000 | [diff] [blame] | 338 | int tp_maxalloc; |
| 339 | struct _typeobject *tp_next; |
| 340 | #endif |
Guido van Rossum | caa6380 | 1995-01-12 11:45:45 +0000 | [diff] [blame] | 341 | } PyTypeObject; |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 342 | |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 343 | |
Guido van Rossum | e5c691a | 2003-03-07 15:13:17 +0000 | [diff] [blame] | 344 | /* The *real* layout of a type object when allocated on the heap */ |
| 345 | typedef struct _heaptypeobject { |
| 346 | /* Note: there's a dependency on the order of these members |
| 347 | in slotptr() in typeobject.c . */ |
Georg Brandl | c255c7b | 2006-02-20 22:27:28 +0000 | [diff] [blame] | 348 | PyTypeObject ht_type; |
Guido van Rossum | e5c691a | 2003-03-07 15:13:17 +0000 | [diff] [blame] | 349 | PyNumberMethods as_number; |
| 350 | PyMappingMethods as_mapping; |
| 351 | PySequenceMethods as_sequence; /* as_sequence comes after as_mapping, |
| 352 | so that the mapping wins when both |
| 353 | the mapping and the sequence define |
| 354 | a given operator (e.g. __getitem__). |
| 355 | see add_operators() in typeobject.c . */ |
| 356 | PyBufferProcs as_buffer; |
Georg Brandl | c255c7b | 2006-02-20 22:27:28 +0000 | [diff] [blame] | 357 | PyObject *ht_name, *ht_slots; |
Guido van Rossum | e5c691a | 2003-03-07 15:13:17 +0000 | [diff] [blame] | 358 | /* here are optional user slots, followed by the members. */ |
| 359 | } PyHeapTypeObject; |
| 360 | |
| 361 | /* access macro to the members which are floating "behind" the object */ |
| 362 | #define PyHeapType_GET_MEMBERS(etype) \ |
Georg Brandl | c255c7b | 2006-02-20 22:27:28 +0000 | [diff] [blame] | 363 | ((PyMemberDef *)(((char *)etype) + (etype)->ht_type.ob_type->tp_basicsize)) |
Guido van Rossum | e5c691a | 2003-03-07 15:13:17 +0000 | [diff] [blame] | 364 | |
| 365 | |
Tim Peters | 6d6c1a3 | 2001-08-02 04:15:00 +0000 | [diff] [blame] | 366 | /* Generic type check */ |
Mark Hammond | a290527 | 2002-07-29 13:42:14 +0000 | [diff] [blame] | 367 | PyAPI_FUNC(int) PyType_IsSubtype(PyTypeObject *, PyTypeObject *); |
Tim Peters | 6d6c1a3 | 2001-08-02 04:15:00 +0000 | [diff] [blame] | 368 | #define PyObject_TypeCheck(ob, tp) \ |
| 369 | ((ob)->ob_type == (tp) || PyType_IsSubtype((ob)->ob_type, (tp))) |
| 370 | |
Mark Hammond | a290527 | 2002-07-29 13:42:14 +0000 | [diff] [blame] | 371 | PyAPI_DATA(PyTypeObject) PyType_Type; /* built-in 'type' */ |
| 372 | PyAPI_DATA(PyTypeObject) PyBaseObject_Type; /* built-in 'object' */ |
| 373 | PyAPI_DATA(PyTypeObject) PySuper_Type; /* built-in 'super' */ |
Tim Peters | 6d6c1a3 | 2001-08-02 04:15:00 +0000 | [diff] [blame] | 374 | |
| 375 | #define PyType_Check(op) PyObject_TypeCheck(op, &PyType_Type) |
Tim Peters | 3abca12 | 2001-10-27 19:37:48 +0000 | [diff] [blame] | 376 | #define PyType_CheckExact(op) ((op)->ob_type == &PyType_Type) |
Tim Peters | 6d6c1a3 | 2001-08-02 04:15:00 +0000 | [diff] [blame] | 377 | |
Mark Hammond | a290527 | 2002-07-29 13:42:14 +0000 | [diff] [blame] | 378 | PyAPI_FUNC(int) PyType_Ready(PyTypeObject *); |
Martin v. Löwis | 18e1655 | 2006-02-15 17:27:45 +0000 | [diff] [blame] | 379 | PyAPI_FUNC(PyObject *) PyType_GenericAlloc(PyTypeObject *, Py_ssize_t); |
Mark Hammond | a290527 | 2002-07-29 13:42:14 +0000 | [diff] [blame] | 380 | PyAPI_FUNC(PyObject *) PyType_GenericNew(PyTypeObject *, |
Tim Peters | 6d6c1a3 | 2001-08-02 04:15:00 +0000 | [diff] [blame] | 381 | PyObject *, PyObject *); |
Mark Hammond | a290527 | 2002-07-29 13:42:14 +0000 | [diff] [blame] | 382 | PyAPI_FUNC(PyObject *) _PyType_Lookup(PyTypeObject *, PyObject *); |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 383 | |
Guido van Rossum | 3f5da24 | 1990-12-20 15:06:42 +0000 | [diff] [blame] | 384 | /* Generic operations on objects */ |
Mark Hammond | a290527 | 2002-07-29 13:42:14 +0000 | [diff] [blame] | 385 | PyAPI_FUNC(int) PyObject_Print(PyObject *, FILE *, int); |
| 386 | PyAPI_FUNC(void) _PyObject_Dump(PyObject *); |
| 387 | PyAPI_FUNC(PyObject *) PyObject_Repr(PyObject *); |
Neil Schemenauer | cf52c07 | 2005-08-12 17:34:58 +0000 | [diff] [blame] | 388 | PyAPI_FUNC(PyObject *) _PyObject_Str(PyObject *); |
Mark Hammond | a290527 | 2002-07-29 13:42:14 +0000 | [diff] [blame] | 389 | PyAPI_FUNC(PyObject *) PyObject_Str(PyObject *); |
Martin v. Löwis | 339d0f7 | 2001-08-17 18:39:25 +0000 | [diff] [blame] | 390 | #ifdef Py_USING_UNICODE |
Mark Hammond | a290527 | 2002-07-29 13:42:14 +0000 | [diff] [blame] | 391 | PyAPI_FUNC(PyObject *) PyObject_Unicode(PyObject *); |
Martin v. Löwis | 339d0f7 | 2001-08-17 18:39:25 +0000 | [diff] [blame] | 392 | #endif |
Mark Hammond | a290527 | 2002-07-29 13:42:14 +0000 | [diff] [blame] | 393 | PyAPI_FUNC(int) PyObject_Compare(PyObject *, PyObject *); |
| 394 | PyAPI_FUNC(PyObject *) PyObject_RichCompare(PyObject *, PyObject *, int); |
| 395 | PyAPI_FUNC(int) PyObject_RichCompareBool(PyObject *, PyObject *, int); |
Jeremy Hylton | af68c87 | 2005-12-10 18:50:16 +0000 | [diff] [blame] | 396 | PyAPI_FUNC(PyObject *) PyObject_GetAttrString(PyObject *, const char *); |
| 397 | PyAPI_FUNC(int) PyObject_SetAttrString(PyObject *, const char *, PyObject *); |
| 398 | PyAPI_FUNC(int) PyObject_HasAttrString(PyObject *, const char *); |
Mark Hammond | a290527 | 2002-07-29 13:42:14 +0000 | [diff] [blame] | 399 | PyAPI_FUNC(PyObject *) PyObject_GetAttr(PyObject *, PyObject *); |
| 400 | PyAPI_FUNC(int) PyObject_SetAttr(PyObject *, PyObject *, PyObject *); |
| 401 | PyAPI_FUNC(int) PyObject_HasAttr(PyObject *, PyObject *); |
| 402 | PyAPI_FUNC(PyObject **) _PyObject_GetDictPtr(PyObject *); |
Raymond Hettinger | 1da1dbf | 2003-03-17 19:46:11 +0000 | [diff] [blame] | 403 | PyAPI_FUNC(PyObject *) PyObject_SelfIter(PyObject *); |
Mark Hammond | a290527 | 2002-07-29 13:42:14 +0000 | [diff] [blame] | 404 | PyAPI_FUNC(PyObject *) PyObject_GenericGetAttr(PyObject *, PyObject *); |
| 405 | PyAPI_FUNC(int) PyObject_GenericSetAttr(PyObject *, |
Tim Peters | 6d6c1a3 | 2001-08-02 04:15:00 +0000 | [diff] [blame] | 406 | PyObject *, PyObject *); |
Mark Hammond | a290527 | 2002-07-29 13:42:14 +0000 | [diff] [blame] | 407 | PyAPI_FUNC(long) PyObject_Hash(PyObject *); |
| 408 | PyAPI_FUNC(int) PyObject_IsTrue(PyObject *); |
| 409 | PyAPI_FUNC(int) PyObject_Not(PyObject *); |
| 410 | PyAPI_FUNC(int) PyCallable_Check(PyObject *); |
| 411 | PyAPI_FUNC(int) PyNumber_Coerce(PyObject **, PyObject **); |
| 412 | PyAPI_FUNC(int) PyNumber_CoerceEx(PyObject **, PyObject **); |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 413 | |
Mark Hammond | a290527 | 2002-07-29 13:42:14 +0000 | [diff] [blame] | 414 | PyAPI_FUNC(void) PyObject_ClearWeakRefs(PyObject *); |
Fred Drake | 41deb1e | 2001-02-01 05:27:45 +0000 | [diff] [blame] | 415 | |
Guido van Rossum | ab3b034 | 2001-09-18 20:38:53 +0000 | [diff] [blame] | 416 | /* A slot function whose address we need to compare */ |
| 417 | extern int _PyObject_SlotCompare(PyObject *, PyObject *); |
| 418 | |
| 419 | |
Tim Peters | 7eea37e | 2001-09-04 22:08:56 +0000 | [diff] [blame] | 420 | /* PyObject_Dir(obj) acts like Python __builtin__.dir(obj), returning a |
| 421 | list of strings. PyObject_Dir(NULL) is like __builtin__.dir(), |
| 422 | returning the names of the current locals. In this case, if there are |
| 423 | no current locals, NULL is returned, and PyErr_Occurred() is false. |
| 424 | */ |
Mark Hammond | a290527 | 2002-07-29 13:42:14 +0000 | [diff] [blame] | 425 | PyAPI_FUNC(PyObject *) PyObject_Dir(PyObject *); |
Tim Peters | 7eea37e | 2001-09-04 22:08:56 +0000 | [diff] [blame] | 426 | |
| 427 | |
Guido van Rossum | 26d4ac3 | 1998-04-10 22:32:24 +0000 | [diff] [blame] | 428 | /* Helpers for printing recursive container types */ |
Mark Hammond | a290527 | 2002-07-29 13:42:14 +0000 | [diff] [blame] | 429 | PyAPI_FUNC(int) Py_ReprEnter(PyObject *); |
| 430 | PyAPI_FUNC(void) Py_ReprLeave(PyObject *); |
Guido van Rossum | 26d4ac3 | 1998-04-10 22:32:24 +0000 | [diff] [blame] | 431 | |
Fred Drake | 13634cf | 2000-06-29 19:17:04 +0000 | [diff] [blame] | 432 | /* Helpers for hash functions */ |
Mark Hammond | a290527 | 2002-07-29 13:42:14 +0000 | [diff] [blame] | 433 | PyAPI_FUNC(long) _Py_HashDouble(double); |
| 434 | PyAPI_FUNC(long) _Py_HashPointer(void*); |
Fred Drake | 13634cf | 2000-06-29 19:17:04 +0000 | [diff] [blame] | 435 | |
Jeremy Hylton | 483638c | 2001-02-01 20:20:45 +0000 | [diff] [blame] | 436 | /* Helper for passing objects to printf and the like */ |
| 437 | #define PyObject_REPR(obj) PyString_AS_STRING(PyObject_Repr(obj)) |
| 438 | |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 439 | /* Flag bits for printing: */ |
Guido van Rossum | caa6380 | 1995-01-12 11:45:45 +0000 | [diff] [blame] | 440 | #define Py_PRINT_RAW 1 /* No string quotes etc. */ |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 441 | |
| 442 | /* |
Tim Peters | 4be93d0 | 2002-07-07 19:59:50 +0000 | [diff] [blame] | 443 | `Type flags (tp_flags) |
Guido van Rossum | 36eef3c | 1998-10-08 02:10:56 +0000 | [diff] [blame] | 444 | |
| 445 | These flags are used to extend the type structure in a backwards-compatible |
| 446 | fashion. Extensions can use the flags to indicate (and test) when a given |
| 447 | type structure contains a new feature. The Python core will use these when |
| 448 | introducing new functionality between major revisions (to avoid mid-version |
| 449 | changes in the PYTHON_API_VERSION). |
| 450 | |
| 451 | Arbitration of the flag bit positions will need to be coordinated among |
| 452 | all extension writers who publically release their extensions (this will |
| 453 | be fewer than you might expect!).. |
| 454 | |
| 455 | Python 1.5.2 introduced the bf_getcharbuffer slot into PyBufferProcs. |
| 456 | |
| 457 | Type definitions should use Py_TPFLAGS_DEFAULT for their tp_flags value. |
| 458 | |
| 459 | Code can use PyType_HasFeature(type_ob, flag_value) to test whether the |
| 460 | given type object has a specified feature. |
Guido van Rossum | 36eef3c | 1998-10-08 02:10:56 +0000 | [diff] [blame] | 461 | */ |
| 462 | |
| 463 | /* PyBufferProcs contains bf_getcharbuffer */ |
| 464 | #define Py_TPFLAGS_HAVE_GETCHARBUFFER (1L<<0) |
| 465 | |
Guido van Rossum | cecb27a | 2000-02-28 15:00:40 +0000 | [diff] [blame] | 466 | /* PySequenceMethods contains sq_contains */ |
| 467 | #define Py_TPFLAGS_HAVE_SEQUENCE_IN (1L<<1) |
| 468 | |
Neil Schemenauer | 31ec142 | 2001-08-29 23:46:35 +0000 | [diff] [blame] | 469 | /* This is here for backwards compatibility. Extensions that use the old GC |
| 470 | * API will still compile but the objects will not be tracked by the GC. */ |
| 471 | #define Py_TPFLAGS_GC 0 /* used to be (1L<<2) */ |
Jeremy Hylton | d08b4c4 | 2000-06-23 19:37:02 +0000 | [diff] [blame] | 472 | |
Thomas Wouters | dd8dbdb | 2000-08-24 20:09:45 +0000 | [diff] [blame] | 473 | /* PySequenceMethods and PyNumberMethods contain in-place operators */ |
| 474 | #define Py_TPFLAGS_HAVE_INPLACEOPS (1L<<3) |
| 475 | |
Neil Schemenauer | a7ed694 | 2001-01-04 01:31:50 +0000 | [diff] [blame] | 476 | /* PyNumberMethods do their own coercion */ |
Guido van Rossum | 5f284ce | 2001-01-17 15:20:39 +0000 | [diff] [blame] | 477 | #define Py_TPFLAGS_CHECKTYPES (1L<<4) |
Neil Schemenauer | a7ed694 | 2001-01-04 01:31:50 +0000 | [diff] [blame] | 478 | |
Guido van Rossum | 59d1d2b | 2001-04-20 19:13:02 +0000 | [diff] [blame] | 479 | /* tp_richcompare is defined */ |
Guido van Rossum | bacca54 | 2001-01-24 22:13:48 +0000 | [diff] [blame] | 480 | #define Py_TPFLAGS_HAVE_RICHCOMPARE (1L<<5) |
| 481 | |
Fred Drake | 033f312 | 2001-02-02 18:17:30 +0000 | [diff] [blame] | 482 | /* Objects which are weakly referencable if their tp_weaklistoffset is >0 */ |
Fred Drake | 033f312 | 2001-02-02 18:17:30 +0000 | [diff] [blame] | 483 | #define Py_TPFLAGS_HAVE_WEAKREFS (1L<<6) |
| 484 | |
Guido van Rossum | 59d1d2b | 2001-04-20 19:13:02 +0000 | [diff] [blame] | 485 | /* tp_iter is defined */ |
| 486 | #define Py_TPFLAGS_HAVE_ITER (1L<<7) |
| 487 | |
Guido van Rossum | 4668b00 | 2001-08-08 05:00:18 +0000 | [diff] [blame] | 488 | /* New members introduced by Python 2.2 exist */ |
Tim Peters | 6d6c1a3 | 2001-08-02 04:15:00 +0000 | [diff] [blame] | 489 | #define Py_TPFLAGS_HAVE_CLASS (1L<<8) |
| 490 | |
| 491 | /* Set if the type object is dynamically allocated */ |
| 492 | #define Py_TPFLAGS_HEAPTYPE (1L<<9) |
| 493 | |
| 494 | /* Set if the type allows subclassing */ |
| 495 | #define Py_TPFLAGS_BASETYPE (1L<<10) |
| 496 | |
Guido van Rossum | 9b9c972 | 2001-08-10 17:37:02 +0000 | [diff] [blame] | 497 | /* Set if the type is 'ready' -- fully initialized */ |
| 498 | #define Py_TPFLAGS_READY (1L<<12) |
| 499 | |
| 500 | /* Set while the type is being 'readied', to prevent recursive ready calls */ |
| 501 | #define Py_TPFLAGS_READYING (1L<<13) |
| 502 | |
Neil Schemenauer | 31ec142 | 2001-08-29 23:46:35 +0000 | [diff] [blame] | 503 | /* Objects support garbage collection (see objimp.h) */ |
Neil Schemenauer | 31ec142 | 2001-08-29 23:46:35 +0000 | [diff] [blame] | 504 | #define Py_TPFLAGS_HAVE_GC (1L<<14) |
Neil Schemenauer | 31ec142 | 2001-08-29 23:46:35 +0000 | [diff] [blame] | 505 | |
Christian Tismer | 661a9e3 | 2003-05-23 12:47:36 +0000 | [diff] [blame] | 506 | /* These two bits are preserved for Stackless Python, next after this is 16 */ |
Christian Tismer | 6695ba8 | 2003-05-20 15:14:31 +0000 | [diff] [blame] | 507 | #ifdef STACKLESS |
Christian Tismer | 661a9e3 | 2003-05-23 12:47:36 +0000 | [diff] [blame] | 508 | #define Py_TPFLAGS_HAVE_STACKLESS_EXTENSION (3L<<15) |
Christian Tismer | 6695ba8 | 2003-05-20 15:14:31 +0000 | [diff] [blame] | 509 | #else |
Christian Tismer | c26ff41 | 2003-05-23 03:33:35 +0000 | [diff] [blame] | 510 | #define Py_TPFLAGS_HAVE_STACKLESS_EXTENSION 0 |
Christian Tismer | 6695ba8 | 2003-05-20 15:14:31 +0000 | [diff] [blame] | 511 | #endif |
| 512 | |
Guido van Rossum | bacca54 | 2001-01-24 22:13:48 +0000 | [diff] [blame] | 513 | #define Py_TPFLAGS_DEFAULT ( \ |
| 514 | Py_TPFLAGS_HAVE_GETCHARBUFFER | \ |
Thomas Wouters | dd8dbdb | 2000-08-24 20:09:45 +0000 | [diff] [blame] | 515 | Py_TPFLAGS_HAVE_SEQUENCE_IN | \ |
Guido van Rossum | bacca54 | 2001-01-24 22:13:48 +0000 | [diff] [blame] | 516 | Py_TPFLAGS_HAVE_INPLACEOPS | \ |
| 517 | Py_TPFLAGS_HAVE_RICHCOMPARE | \ |
Fred Drake | 033f312 | 2001-02-02 18:17:30 +0000 | [diff] [blame] | 518 | Py_TPFLAGS_HAVE_WEAKREFS | \ |
Guido van Rossum | 59d1d2b | 2001-04-20 19:13:02 +0000 | [diff] [blame] | 519 | Py_TPFLAGS_HAVE_ITER | \ |
Tim Peters | 6d6c1a3 | 2001-08-02 04:15:00 +0000 | [diff] [blame] | 520 | Py_TPFLAGS_HAVE_CLASS | \ |
Christian Tismer | c26ff41 | 2003-05-23 03:33:35 +0000 | [diff] [blame] | 521 | Py_TPFLAGS_HAVE_STACKLESS_EXTENSION | \ |
Guido van Rossum | bacca54 | 2001-01-24 22:13:48 +0000 | [diff] [blame] | 522 | 0) |
Guido van Rossum | 36eef3c | 1998-10-08 02:10:56 +0000 | [diff] [blame] | 523 | |
| 524 | #define PyType_HasFeature(t,f) (((t)->tp_flags & (f)) != 0) |
| 525 | |
| 526 | |
| 527 | /* |
Guido van Rossum | caa6380 | 1995-01-12 11:45:45 +0000 | [diff] [blame] | 528 | The macros Py_INCREF(op) and Py_DECREF(op) are used to increment or decrement |
Tim Peters | 4be93d0 | 2002-07-07 19:59:50 +0000 | [diff] [blame] | 529 | reference counts. Py_DECREF calls the object's deallocator function when |
| 530 | the refcount falls to 0; for |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 531 | objects that don't contain references to other objects or heap memory |
| 532 | this can be the standard function free(). Both macros can be used |
Tim Peters | 4be93d0 | 2002-07-07 19:59:50 +0000 | [diff] [blame] | 533 | wherever a void expression is allowed. The argument must not be a |
| 534 | NIL pointer. If it may be NIL, use Py_XINCREF/Py_XDECREF instead. |
| 535 | The macro _Py_NewReference(op) initialize reference counts to 1, and |
| 536 | in special builds (Py_REF_DEBUG, Py_TRACE_REFS) performs additional |
| 537 | bookkeeping appropriate to the special build. |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 538 | |
| 539 | We assume that the reference count field can never overflow; this can |
Tim Peters | 4be93d0 | 2002-07-07 19:59:50 +0000 | [diff] [blame] | 540 | be proven when the size of the field is the same as the pointer size, so |
| 541 | we ignore the possibility. Provided a C int is at least 32 bits (which |
| 542 | is implicitly assumed in many parts of this code), that's enough for |
| 543 | about 2**31 references to an object. |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 544 | |
Tim Peters | 4be93d0 | 2002-07-07 19:59:50 +0000 | [diff] [blame] | 545 | XXX The following became out of date in Python 2.2, but I'm not sure |
| 546 | XXX what the full truth is now. Certainly, heap-allocated type objects |
| 547 | XXX can and should be deallocated. |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 548 | Type objects should never be deallocated; the type pointer in an object |
| 549 | is not considered to be a reference to the type object, to save |
| 550 | complications in the deallocation function. (This is actually a |
| 551 | decision that's up to the implementer of each new type so if you want, |
| 552 | you can count such references to the type object.) |
| 553 | |
Guido van Rossum | caa6380 | 1995-01-12 11:45:45 +0000 | [diff] [blame] | 554 | *** WARNING*** The Py_DECREF macro must have a side-effect-free argument |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 555 | since it may evaluate its argument multiple times. (The alternative |
| 556 | would be to mace it a proper function or assign it to a global temporary |
| 557 | variable first, both of which are slower; and in a multi-threaded |
| 558 | environment the global variable trick is not safe.) |
| 559 | */ |
| 560 | |
Tim Peters | 3459251 | 2002-07-11 06:23:50 +0000 | [diff] [blame] | 561 | /* First define a pile of simple helper macros, one set per special |
| 562 | * build symbol. These either expand to the obvious things, or to |
| 563 | * nothing at all when the special mode isn't in effect. The main |
| 564 | * macros can later be defined just once then, yet expand to different |
| 565 | * things depending on which special build options are and aren't in effect. |
| 566 | * Trust me <wink>: while painful, this is 20x easier to understand than, |
| 567 | * e.g, defining _Py_NewReference five different times in a maze of nested |
| 568 | * #ifdefs (we used to do that -- it was impenetrable). |
| 569 | */ |
Tim Peters | 4be93d0 | 2002-07-07 19:59:50 +0000 | [diff] [blame] | 570 | #ifdef Py_REF_DEBUG |
Mark Hammond | a290527 | 2002-07-29 13:42:14 +0000 | [diff] [blame] | 571 | PyAPI_DATA(long) _Py_RefTotal; |
| 572 | PyAPI_FUNC(void) _Py_NegativeRefcount(const char *fname, |
Tim Peters | 7c321a8 | 2002-07-09 02:57:01 +0000 | [diff] [blame] | 573 | int lineno, PyObject *op); |
Tim Peters | 3459251 | 2002-07-11 06:23:50 +0000 | [diff] [blame] | 574 | #define _Py_INC_REFTOTAL _Py_RefTotal++ |
| 575 | #define _Py_DEC_REFTOTAL _Py_RefTotal-- |
| 576 | #define _Py_REF_DEBUG_COMMA , |
| 577 | #define _Py_CHECK_REFCNT(OP) \ |
Tim Peters | 7c321a8 | 2002-07-09 02:57:01 +0000 | [diff] [blame] | 578 | { if ((OP)->ob_refcnt < 0) \ |
| 579 | _Py_NegativeRefcount(__FILE__, __LINE__, \ |
| 580 | (PyObject *)(OP)); \ |
| 581 | } |
Tim Peters | 4be93d0 | 2002-07-07 19:59:50 +0000 | [diff] [blame] | 582 | #else |
Tim Peters | 3459251 | 2002-07-11 06:23:50 +0000 | [diff] [blame] | 583 | #define _Py_INC_REFTOTAL |
| 584 | #define _Py_DEC_REFTOTAL |
| 585 | #define _Py_REF_DEBUG_COMMA |
| 586 | #define _Py_CHECK_REFCNT(OP) /* a semicolon */; |
Tim Peters | 57f4ddd | 2002-07-10 06:34:15 +0000 | [diff] [blame] | 587 | #endif /* Py_REF_DEBUG */ |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 588 | |
Sjoerd Mullender | a9c3c22 | 1993-10-11 12:54:31 +0000 | [diff] [blame] | 589 | #ifdef COUNT_ALLOCS |
Mark Hammond | a290527 | 2002-07-29 13:42:14 +0000 | [diff] [blame] | 590 | PyAPI_FUNC(void) inc_count(PyTypeObject *); |
Tim Peters | 3459251 | 2002-07-11 06:23:50 +0000 | [diff] [blame] | 591 | #define _Py_INC_TPALLOCS(OP) inc_count((OP)->ob_type) |
| 592 | #define _Py_INC_TPFREES(OP) (OP)->ob_type->tp_frees++ |
| 593 | #define _Py_DEC_TPFREES(OP) (OP)->ob_type->tp_frees-- |
| 594 | #define _Py_COUNT_ALLOCS_COMMA , |
Sjoerd Mullender | a9c3c22 | 1993-10-11 12:54:31 +0000 | [diff] [blame] | 595 | #else |
Tim Peters | 3459251 | 2002-07-11 06:23:50 +0000 | [diff] [blame] | 596 | #define _Py_INC_TPALLOCS(OP) |
| 597 | #define _Py_INC_TPFREES(OP) |
| 598 | #define _Py_DEC_TPFREES(OP) |
| 599 | #define _Py_COUNT_ALLOCS_COMMA |
Tim Peters | 57f4ddd | 2002-07-10 06:34:15 +0000 | [diff] [blame] | 600 | #endif /* COUNT_ALLOCS */ |
Tim Peters | 4be93d0 | 2002-07-07 19:59:50 +0000 | [diff] [blame] | 601 | |
| 602 | #ifdef Py_TRACE_REFS |
| 603 | /* Py_TRACE_REFS is such major surgery that we call external routines. */ |
Mark Hammond | a290527 | 2002-07-29 13:42:14 +0000 | [diff] [blame] | 604 | PyAPI_FUNC(void) _Py_NewReference(PyObject *); |
| 605 | PyAPI_FUNC(void) _Py_ForgetReference(PyObject *); |
| 606 | PyAPI_FUNC(void) _Py_Dealloc(PyObject *); |
| 607 | PyAPI_FUNC(void) _Py_PrintReferences(FILE *); |
Tim Peters | 269b2a6 | 2003-04-17 19:52:29 +0000 | [diff] [blame] | 608 | PyAPI_FUNC(void) _Py_PrintReferenceAddresses(FILE *); |
Tim Peters | 7571a0f | 2003-03-23 17:52:28 +0000 | [diff] [blame] | 609 | PyAPI_FUNC(void) _Py_AddToAllObjects(PyObject *, int force); |
Tim Peters | 4be93d0 | 2002-07-07 19:59:50 +0000 | [diff] [blame] | 610 | |
| 611 | #else |
| 612 | /* Without Py_TRACE_REFS, there's little enough to do that we expand code |
| 613 | * inline. |
| 614 | */ |
Tim Peters | 3459251 | 2002-07-11 06:23:50 +0000 | [diff] [blame] | 615 | #define _Py_NewReference(op) ( \ |
| 616 | _Py_INC_TPALLOCS(op) _Py_COUNT_ALLOCS_COMMA \ |
| 617 | _Py_INC_REFTOTAL _Py_REF_DEBUG_COMMA \ |
Tim Peters | 4be93d0 | 2002-07-07 19:59:50 +0000 | [diff] [blame] | 618 | (op)->ob_refcnt = 1) |
| 619 | |
Tim Peters | 3459251 | 2002-07-11 06:23:50 +0000 | [diff] [blame] | 620 | #define _Py_ForgetReference(op) _Py_INC_TPFREES(op) |
Tim Peters | 4be93d0 | 2002-07-07 19:59:50 +0000 | [diff] [blame] | 621 | |
Tim Peters | 57f4ddd | 2002-07-10 06:34:15 +0000 | [diff] [blame] | 622 | #define _Py_Dealloc(op) ( \ |
Tim Peters | 3459251 | 2002-07-11 06:23:50 +0000 | [diff] [blame] | 623 | _Py_INC_TPFREES(op) _Py_COUNT_ALLOCS_COMMA \ |
Tim Peters | 4be93d0 | 2002-07-07 19:59:50 +0000 | [diff] [blame] | 624 | (*(op)->ob_type->tp_dealloc)((PyObject *)(op))) |
Guido van Rossum | 60be1db | 1996-05-22 16:33:22 +0000 | [diff] [blame] | 625 | #endif /* !Py_TRACE_REFS */ |
| 626 | |
Tim Peters | 3459251 | 2002-07-11 06:23:50 +0000 | [diff] [blame] | 627 | #define Py_INCREF(op) ( \ |
| 628 | _Py_INC_REFTOTAL _Py_REF_DEBUG_COMMA \ |
Tim Peters | 4be93d0 | 2002-07-07 19:59:50 +0000 | [diff] [blame] | 629 | (op)->ob_refcnt++) |
| 630 | |
Tim Peters | 3459251 | 2002-07-11 06:23:50 +0000 | [diff] [blame] | 631 | #define Py_DECREF(op) \ |
| 632 | if (_Py_DEC_REFTOTAL _Py_REF_DEBUG_COMMA \ |
| 633 | --(op)->ob_refcnt != 0) \ |
| 634 | _Py_CHECK_REFCNT(op) \ |
| 635 | else \ |
Guido van Rossum | 1d529d1 | 1997-08-05 02:30:44 +0000 | [diff] [blame] | 636 | _Py_Dealloc((PyObject *)(op)) |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 637 | |
Jim Fulton | 8c5aeaa | 2004-07-14 19:07:35 +0000 | [diff] [blame] | 638 | #define Py_CLEAR(op) \ |
| 639 | do { \ |
| 640 | if (op) { \ |
Raymond Hettinger | 75ccea3 | 2004-09-01 07:02:44 +0000 | [diff] [blame] | 641 | PyObject *tmp = (PyObject *)(op); \ |
Jim Fulton | 8c5aeaa | 2004-07-14 19:07:35 +0000 | [diff] [blame] | 642 | (op) = NULL; \ |
| 643 | Py_DECREF(tmp); \ |
| 644 | } \ |
| 645 | } while (0) |
| 646 | |
Guido van Rossum | 3f5da24 | 1990-12-20 15:06:42 +0000 | [diff] [blame] | 647 | /* Macros to use in case the object pointer may be NULL: */ |
Guido van Rossum | caa6380 | 1995-01-12 11:45:45 +0000 | [diff] [blame] | 648 | #define Py_XINCREF(op) if ((op) == NULL) ; else Py_INCREF(op) |
| 649 | #define Py_XDECREF(op) if ((op) == NULL) ; else Py_DECREF(op) |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 650 | |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 651 | /* |
Thomas Heller | 1328b52 | 2004-04-22 17:23:49 +0000 | [diff] [blame] | 652 | These are provided as conveniences to Python runtime embedders, so that |
| 653 | they can have object code that is not dependent on Python compilation flags. |
| 654 | */ |
| 655 | PyAPI_FUNC(void) Py_IncRef(PyObject *); |
| 656 | PyAPI_FUNC(void) Py_DecRef(PyObject *); |
| 657 | |
| 658 | /* |
Guido van Rossum | caa6380 | 1995-01-12 11:45:45 +0000 | [diff] [blame] | 659 | _Py_NoneStruct is an object of undefined type which can be used in contexts |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 660 | where NULL (nil) is not suitable (since NULL often means 'error'). |
| 661 | |
Guido van Rossum | caa6380 | 1995-01-12 11:45:45 +0000 | [diff] [blame] | 662 | Don't forget to apply Py_INCREF() when returning this value!!! |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 663 | */ |
Mark Hammond | a290527 | 2002-07-29 13:42:14 +0000 | [diff] [blame] | 664 | PyAPI_DATA(PyObject) _Py_NoneStruct; /* Don't use this directly */ |
Guido van Rossum | caa6380 | 1995-01-12 11:45:45 +0000 | [diff] [blame] | 665 | #define Py_None (&_Py_NoneStruct) |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 666 | |
Brett Cannon | d05235e | 2003-10-19 21:19:40 +0000 | [diff] [blame] | 667 | /* Macro for returning Py_None from a function */ |
Tim Peters | 5980ff2 | 2004-07-22 01:46:43 +0000 | [diff] [blame] | 668 | #define Py_RETURN_NONE return Py_INCREF(Py_None), Py_None |
Brett Cannon | d05235e | 2003-10-19 21:19:40 +0000 | [diff] [blame] | 669 | |
Neil Schemenauer | a7ed694 | 2001-01-04 01:31:50 +0000 | [diff] [blame] | 670 | /* |
| 671 | Py_NotImplemented is a singleton used to signal that an operation is |
| 672 | not implemented for a given type combination. |
| 673 | */ |
Mark Hammond | a290527 | 2002-07-29 13:42:14 +0000 | [diff] [blame] | 674 | PyAPI_DATA(PyObject) _Py_NotImplementedStruct; /* Don't use this directly */ |
Neil Schemenauer | a7ed694 | 2001-01-04 01:31:50 +0000 | [diff] [blame] | 675 | #define Py_NotImplemented (&_Py_NotImplementedStruct) |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 676 | |
Guido van Rossum | 5f284ce | 2001-01-17 15:20:39 +0000 | [diff] [blame] | 677 | /* Rich comparison opcodes */ |
| 678 | #define Py_LT 0 |
| 679 | #define Py_LE 1 |
| 680 | #define Py_EQ 2 |
| 681 | #define Py_NE 3 |
| 682 | #define Py_GT 4 |
| 683 | #define Py_GE 5 |
| 684 | |
Tim Peters | f4aca75 | 2004-09-23 02:39:37 +0000 | [diff] [blame] | 685 | /* Maps Py_LT to Py_GT, ..., Py_GE to Py_LE. |
| 686 | * Defined in object.c. |
| 687 | */ |
| 688 | PyAPI_DATA(int) _Py_SwappedOp[]; |
| 689 | |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 690 | /* |
Jeremy Hylton | 938ace6 | 2002-07-17 16:30:39 +0000 | [diff] [blame] | 691 | Define staticforward and statichere for source compatibility with old |
| 692 | C extensions. |
| 693 | |
| 694 | The staticforward define was needed to support certain broken C |
| 695 | compilers (notably SCO ODT 3.0, perhaps early AIX as well) botched the |
| 696 | static keyword when it was used with a forward declaration of a static |
| 697 | initialized structure. Standard C allows the forward declaration with |
| 698 | static, and we've decided to stop catering to broken C compilers. |
| 699 | (In fact, we expect that the compilers are all fixed eight years later.) |
Guido van Rossum | b6775db | 1994-08-01 11:34:53 +0000 | [diff] [blame] | 700 | */ |
| 701 | |
Guido van Rossum | b6775db | 1994-08-01 11:34:53 +0000 | [diff] [blame] | 702 | #define staticforward static |
Guido van Rossum | 57836fe | 1995-02-21 21:06:10 +0000 | [diff] [blame] | 703 | #define statichere static |
Guido van Rossum | b6775db | 1994-08-01 11:34:53 +0000 | [diff] [blame] | 704 | |
| 705 | |
| 706 | /* |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 707 | More conventions |
| 708 | ================ |
| 709 | |
| 710 | Argument Checking |
| 711 | ----------------- |
| 712 | |
| 713 | Functions that take objects as arguments normally don't check for nil |
| 714 | arguments, but they do check the type of the argument, and return an |
| 715 | error if the function doesn't apply to the type. |
| 716 | |
| 717 | Failure Modes |
| 718 | ------------- |
| 719 | |
| 720 | Functions may fail for a variety of reasons, including running out of |
Guido van Rossum | 3f5da24 | 1990-12-20 15:06:42 +0000 | [diff] [blame] | 721 | memory. This is communicated to the caller in two ways: an error string |
| 722 | is set (see errors.h), and the function result differs: functions that |
| 723 | normally return a pointer return NULL for failure, functions returning |
| 724 | an integer return -1 (which could be a legal return value too!), and |
| 725 | other functions return 0 for success and -1 for failure. |
Tim Peters | 4be93d0 | 2002-07-07 19:59:50 +0000 | [diff] [blame] | 726 | Callers should always check for errors before using the result. If |
| 727 | an error was set, the caller must either explicitly clear it, or pass |
| 728 | the error on to its caller. |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 729 | |
| 730 | Reference Counts |
| 731 | ---------------- |
| 732 | |
| 733 | It takes a while to get used to the proper usage of reference counts. |
| 734 | |
| 735 | Functions that create an object set the reference count to 1; such new |
Guido van Rossum | caa6380 | 1995-01-12 11:45:45 +0000 | [diff] [blame] | 736 | objects must be stored somewhere or destroyed again with Py_DECREF(). |
Alex Martelli | 721b776 | 2003-11-09 16:38:39 +0000 | [diff] [blame] | 737 | Some functions that 'store' objects, such as PyTuple_SetItem() and |
| 738 | PyList_SetItem(), |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 739 | don't increment the reference count of the object, since the most |
| 740 | frequent use is to store a fresh object. Functions that 'retrieve' |
Alex Martelli | 721b776 | 2003-11-09 16:38:39 +0000 | [diff] [blame] | 741 | objects, such as PyTuple_GetItem() and PyDict_GetItemString(), also |
Guido van Rossum | caa6380 | 1995-01-12 11:45:45 +0000 | [diff] [blame] | 742 | don't increment |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 743 | the reference count, since most frequently the object is only looked at |
| 744 | quickly. Thus, to retrieve an object and store it again, the caller |
Guido van Rossum | caa6380 | 1995-01-12 11:45:45 +0000 | [diff] [blame] | 745 | must call Py_INCREF() explicitly. |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 746 | |
Alex Martelli | 721b776 | 2003-11-09 16:38:39 +0000 | [diff] [blame] | 747 | NOTE: functions that 'consume' a reference count, like |
| 748 | PyList_SetItem(), consume the reference even if the object wasn't |
| 749 | successfully stored, to simplify error handling. |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 750 | |
| 751 | It seems attractive to make other functions that take an object as |
Alex Martelli | 721b776 | 2003-11-09 16:38:39 +0000 | [diff] [blame] | 752 | argument consume a reference count; however, this may quickly get |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 753 | confusing (even the current practice is already confusing). Consider |
Guido van Rossum | caa6380 | 1995-01-12 11:45:45 +0000 | [diff] [blame] | 754 | it carefully, it may save lots of calls to Py_INCREF() and Py_DECREF() at |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 755 | times. |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 756 | */ |
Guido van Rossum | a330996 | 1993-07-28 09:05:47 +0000 | [diff] [blame] | 757 | |
Guido van Rossum | d724b23 | 2000-03-13 16:01:29 +0000 | [diff] [blame] | 758 | |
Tim Peters | 803526b | 2002-07-07 05:13:56 +0000 | [diff] [blame] | 759 | /* Trashcan mechanism, thanks to Christian Tismer. |
Guido van Rossum | d724b23 | 2000-03-13 16:01:29 +0000 | [diff] [blame] | 760 | |
Tim Peters | 803526b | 2002-07-07 05:13:56 +0000 | [diff] [blame] | 761 | When deallocating a container object, it's possible to trigger an unbounded |
| 762 | chain of deallocations, as each Py_DECREF in turn drops the refcount on "the |
| 763 | next" object in the chain to 0. This can easily lead to stack faults, and |
| 764 | especially in threads (which typically have less stack space to work with). |
Guido van Rossum | d724b23 | 2000-03-13 16:01:29 +0000 | [diff] [blame] | 765 | |
Tim Peters | 803526b | 2002-07-07 05:13:56 +0000 | [diff] [blame] | 766 | A container object that participates in cyclic gc can avoid this by |
| 767 | bracketing the body of its tp_dealloc function with a pair of macros: |
Guido van Rossum | e92e610 | 2000-04-24 15:40:53 +0000 | [diff] [blame] | 768 | |
Tim Peters | 803526b | 2002-07-07 05:13:56 +0000 | [diff] [blame] | 769 | static void |
| 770 | mytype_dealloc(mytype *p) |
| 771 | { |
| 772 | ... declarations go here ... |
| 773 | |
| 774 | PyObject_GC_UnTrack(p); // must untrack first |
| 775 | Py_TRASHCAN_SAFE_BEGIN(p) |
| 776 | ... The body of the deallocator goes here, including all calls ... |
| 777 | ... to Py_DECREF on contained objects. ... |
| 778 | Py_TRASHCAN_SAFE_END(p) |
| 779 | } |
| 780 | |
Tim Peters | 808eb59 | 2002-08-07 20:53:05 +0000 | [diff] [blame] | 781 | CAUTION: Never return from the middle of the body! If the body needs to |
| 782 | "get out early", put a label immediately before the Py_TRASHCAN_SAFE_END |
| 783 | call, and goto it. Else the call-depth counter (see below) will stay |
| 784 | above 0 forever, and the trashcan will never get emptied. |
| 785 | |
Tim Peters | 803526b | 2002-07-07 05:13:56 +0000 | [diff] [blame] | 786 | How it works: The BEGIN macro increments a call-depth counter. So long |
| 787 | as this counter is small, the body of the deallocator is run directly without |
| 788 | further ado. But if the counter gets large, it instead adds p to a list of |
| 789 | objects to be deallocated later, skips the body of the deallocator, and |
| 790 | resumes execution after the END macro. The tp_dealloc routine then returns |
| 791 | without deallocating anything (and so unbounded call-stack depth is avoided). |
| 792 | |
| 793 | When the call stack finishes unwinding again, code generated by the END macro |
| 794 | notices this, and calls another routine to deallocate all the objects that |
| 795 | may have been added to the list of deferred deallocations. In effect, a |
| 796 | chain of N deallocations is broken into N / PyTrash_UNWIND_LEVEL pieces, |
| 797 | with the call stack never exceeding a depth of PyTrash_UNWIND_LEVEL. |
Guido van Rossum | d724b23 | 2000-03-13 16:01:29 +0000 | [diff] [blame] | 798 | */ |
| 799 | |
Mark Hammond | a290527 | 2002-07-29 13:42:14 +0000 | [diff] [blame] | 800 | PyAPI_FUNC(void) _PyTrash_deposit_object(PyObject*); |
| 801 | PyAPI_FUNC(void) _PyTrash_destroy_chain(void); |
| 802 | PyAPI_DATA(int) _PyTrash_delete_nesting; |
| 803 | PyAPI_DATA(PyObject *) _PyTrash_delete_later; |
Tim Peters | 803526b | 2002-07-07 05:13:56 +0000 | [diff] [blame] | 804 | |
Guido van Rossum | d724b23 | 2000-03-13 16:01:29 +0000 | [diff] [blame] | 805 | #define PyTrash_UNWIND_LEVEL 50 |
| 806 | |
| 807 | #define Py_TRASHCAN_SAFE_BEGIN(op) \ |
Tim Peters | 803526b | 2002-07-07 05:13:56 +0000 | [diff] [blame] | 808 | if (_PyTrash_delete_nesting < PyTrash_UNWIND_LEVEL) { \ |
| 809 | ++_PyTrash_delete_nesting; |
| 810 | /* The body of the deallocator is here. */ |
Guido van Rossum | d724b23 | 2000-03-13 16:01:29 +0000 | [diff] [blame] | 811 | #define Py_TRASHCAN_SAFE_END(op) \ |
Guido van Rossum | d724b23 | 2000-03-13 16:01:29 +0000 | [diff] [blame] | 812 | --_PyTrash_delete_nesting; \ |
| 813 | if (_PyTrash_delete_later && _PyTrash_delete_nesting <= 0) \ |
Guido van Rossum | e92e610 | 2000-04-24 15:40:53 +0000 | [diff] [blame] | 814 | _PyTrash_destroy_chain(); \ |
Guido van Rossum | d724b23 | 2000-03-13 16:01:29 +0000 | [diff] [blame] | 815 | } \ |
Tim Peters | 803526b | 2002-07-07 05:13:56 +0000 | [diff] [blame] | 816 | else \ |
| 817 | _PyTrash_deposit_object((PyObject*)op); |
Guido van Rossum | e92e610 | 2000-04-24 15:40:53 +0000 | [diff] [blame] | 818 | |
Guido van Rossum | a330996 | 1993-07-28 09:05:47 +0000 | [diff] [blame] | 819 | #ifdef __cplusplus |
| 820 | } |
| 821 | #endif |
| 822 | #endif /* !Py_OBJECT_H */ |