Andrew Hsieh | 83760d2 | 2013-06-18 12:24:28 -0700 | [diff] [blame] | 1 | #ifndef Py_OBJECT_H |
| 2 | #define Py_OBJECT_H |
| 3 | #ifdef __cplusplus |
| 4 | extern "C" { |
| 5 | #endif |
| 6 | |
| 7 | |
| 8 | /* Object and type object interface */ |
| 9 | |
| 10 | /* |
| 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 |
| 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). |
| 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 | |
| 40 | Objects are always accessed through pointers of the type 'PyObject *'. |
| 41 | The type 'PyObject' is a structure that only contains the reference count |
| 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 |
| 45 | with the reference count and type fields; the macro PyObject_HEAD should be |
| 46 | used for this (to accommodate for future changes). The implementation |
| 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. |
| 52 | */ |
| 53 | |
| 54 | /* Py_DEBUG implies Py_TRACE_REFS. */ |
| 55 | #if defined(Py_DEBUG) && !defined(Py_TRACE_REFS) |
| 56 | #define Py_TRACE_REFS |
| 57 | #endif |
| 58 | |
| 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 |
| 63 | |
| 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 | Py_ssize_t ob_refcnt; \ |
| 81 | struct _typeobject *ob_type; |
| 82 | |
| 83 | #define PyObject_HEAD_INIT(type) \ |
| 84 | _PyObject_EXTRA_INIT \ |
| 85 | 1, type, |
| 86 | |
| 87 | #define PyVarObject_HEAD_INIT(type, size) \ |
| 88 | PyObject_HEAD_INIT(type) size, |
| 89 | |
| 90 | /* PyObject_VAR_HEAD defines the initial segment of all variable-size |
| 91 | * container objects. These end with a declaration of an array with 1 |
| 92 | * element, but enough space is malloc'ed so that the array actually |
| 93 | * has room for ob_size elements. Note that ob_size is an element count, |
| 94 | * not necessarily a byte count. |
| 95 | */ |
| 96 | #define PyObject_VAR_HEAD \ |
| 97 | PyObject_HEAD \ |
| 98 | Py_ssize_t ob_size; /* Number of items in variable part */ |
| 99 | #define Py_INVALID_SIZE (Py_ssize_t)-1 |
| 100 | |
| 101 | /* Nothing is actually declared to be a PyObject, but every pointer to |
| 102 | * a Python object can be cast to a PyObject*. This is inheritance built |
| 103 | * by hand. Similarly every pointer to a variable-size Python object can, |
| 104 | * in addition, be cast to PyVarObject*. |
| 105 | */ |
| 106 | typedef struct _object { |
| 107 | PyObject_HEAD |
| 108 | } PyObject; |
| 109 | |
| 110 | typedef struct { |
| 111 | PyObject_VAR_HEAD |
| 112 | } PyVarObject; |
| 113 | |
| 114 | #define Py_REFCNT(ob) (((PyObject*)(ob))->ob_refcnt) |
| 115 | #define Py_TYPE(ob) (((PyObject*)(ob))->ob_type) |
| 116 | #define Py_SIZE(ob) (((PyVarObject*)(ob))->ob_size) |
| 117 | |
| 118 | /* |
| 119 | Type objects contain a string containing the type name (to help somewhat |
| 120 | in debugging), the allocation parameters (see PyObject_New() and |
| 121 | PyObject_NewVar()), |
| 122 | and methods for accessing objects of the type. Methods are optional, a |
| 123 | nil pointer meaning that particular kind of access is not available for |
| 124 | this type. The Py_DECREF() macro uses the tp_dealloc method without |
| 125 | checking for a nil pointer; it should always be implemented except if |
| 126 | the implementation can guarantee that the reference count will never |
| 127 | reach zero (e.g., for statically allocated type objects). |
| 128 | |
| 129 | NB: the methods for certain type groups are now contained in separate |
| 130 | method blocks. |
| 131 | */ |
| 132 | |
| 133 | typedef PyObject * (*unaryfunc)(PyObject *); |
| 134 | typedef PyObject * (*binaryfunc)(PyObject *, PyObject *); |
| 135 | typedef PyObject * (*ternaryfunc)(PyObject *, PyObject *, PyObject *); |
| 136 | typedef int (*inquiry)(PyObject *); |
| 137 | typedef Py_ssize_t (*lenfunc)(PyObject *); |
| 138 | typedef int (*coercion)(PyObject **, PyObject **); |
| 139 | typedef PyObject *(*intargfunc)(PyObject *, int) Py_DEPRECATED(2.5); |
| 140 | typedef PyObject *(*intintargfunc)(PyObject *, int, int) Py_DEPRECATED(2.5); |
| 141 | typedef PyObject *(*ssizeargfunc)(PyObject *, Py_ssize_t); |
| 142 | typedef PyObject *(*ssizessizeargfunc)(PyObject *, Py_ssize_t, Py_ssize_t); |
| 143 | typedef int(*intobjargproc)(PyObject *, int, PyObject *); |
| 144 | typedef int(*intintobjargproc)(PyObject *, int, int, PyObject *); |
| 145 | typedef int(*ssizeobjargproc)(PyObject *, Py_ssize_t, PyObject *); |
| 146 | typedef int(*ssizessizeobjargproc)(PyObject *, Py_ssize_t, Py_ssize_t, PyObject *); |
| 147 | typedef int(*objobjargproc)(PyObject *, PyObject *, PyObject *); |
| 148 | |
| 149 | |
| 150 | |
| 151 | /* int-based buffer interface */ |
| 152 | typedef int (*getreadbufferproc)(PyObject *, int, void **); |
| 153 | typedef int (*getwritebufferproc)(PyObject *, int, void **); |
| 154 | typedef int (*getsegcountproc)(PyObject *, int *); |
| 155 | typedef int (*getcharbufferproc)(PyObject *, int, char **); |
| 156 | /* ssize_t-based buffer interface */ |
| 157 | typedef Py_ssize_t (*readbufferproc)(PyObject *, Py_ssize_t, void **); |
| 158 | typedef Py_ssize_t (*writebufferproc)(PyObject *, Py_ssize_t, void **); |
| 159 | typedef Py_ssize_t (*segcountproc)(PyObject *, Py_ssize_t *); |
| 160 | typedef Py_ssize_t (*charbufferproc)(PyObject *, Py_ssize_t, char **); |
| 161 | |
| 162 | |
| 163 | /* Py3k buffer interface */ |
| 164 | typedef struct bufferinfo { |
| 165 | void *buf; |
| 166 | PyObject *obj; /* owned reference */ |
| 167 | Py_ssize_t len; |
| 168 | Py_ssize_t itemsize; /* This is Py_ssize_t so it can be |
| 169 | pointed to by strides in simple case.*/ |
| 170 | int readonly; |
| 171 | int ndim; |
| 172 | char *format; |
| 173 | Py_ssize_t *shape; |
| 174 | Py_ssize_t *strides; |
| 175 | Py_ssize_t *suboffsets; |
| 176 | Py_ssize_t smalltable[2]; /* static store for shape and strides of |
| 177 | mono-dimensional buffers. */ |
| 178 | void *internal; |
| 179 | } Py_buffer; |
| 180 | |
| 181 | typedef int (*getbufferproc)(PyObject *, Py_buffer *, int); |
| 182 | typedef void (*releasebufferproc)(PyObject *, Py_buffer *); |
| 183 | |
| 184 | /* Flags for getting buffers */ |
| 185 | #define PyBUF_SIMPLE 0 |
| 186 | #define PyBUF_WRITABLE 0x0001 |
| 187 | /* we used to include an E, backwards compatible alias */ |
| 188 | #define PyBUF_WRITEABLE PyBUF_WRITABLE |
| 189 | #define PyBUF_FORMAT 0x0004 |
| 190 | #define PyBUF_ND 0x0008 |
| 191 | #define PyBUF_STRIDES (0x0010 | PyBUF_ND) |
| 192 | #define PyBUF_C_CONTIGUOUS (0x0020 | PyBUF_STRIDES) |
| 193 | #define PyBUF_F_CONTIGUOUS (0x0040 | PyBUF_STRIDES) |
| 194 | #define PyBUF_ANY_CONTIGUOUS (0x0080 | PyBUF_STRIDES) |
| 195 | #define PyBUF_INDIRECT (0x0100 | PyBUF_STRIDES) |
| 196 | |
| 197 | #define PyBUF_CONTIG (PyBUF_ND | PyBUF_WRITABLE) |
| 198 | #define PyBUF_CONTIG_RO (PyBUF_ND) |
| 199 | |
| 200 | #define PyBUF_STRIDED (PyBUF_STRIDES | PyBUF_WRITABLE) |
| 201 | #define PyBUF_STRIDED_RO (PyBUF_STRIDES) |
| 202 | |
| 203 | #define PyBUF_RECORDS (PyBUF_STRIDES | PyBUF_WRITABLE | PyBUF_FORMAT) |
| 204 | #define PyBUF_RECORDS_RO (PyBUF_STRIDES | PyBUF_FORMAT) |
| 205 | |
| 206 | #define PyBUF_FULL (PyBUF_INDIRECT | PyBUF_WRITABLE | PyBUF_FORMAT) |
| 207 | #define PyBUF_FULL_RO (PyBUF_INDIRECT | PyBUF_FORMAT) |
| 208 | |
| 209 | |
| 210 | #define PyBUF_READ 0x100 |
| 211 | #define PyBUF_WRITE 0x200 |
| 212 | #define PyBUF_SHADOW 0x400 |
| 213 | /* end Py3k buffer interface */ |
| 214 | |
| 215 | typedef int (*objobjproc)(PyObject *, PyObject *); |
| 216 | typedef int (*visitproc)(PyObject *, void *); |
| 217 | typedef int (*traverseproc)(PyObject *, visitproc, void *); |
| 218 | |
| 219 | typedef struct { |
| 220 | /* For numbers without flag bit Py_TPFLAGS_CHECKTYPES set, all |
| 221 | arguments are guaranteed to be of the object's type (modulo |
| 222 | coercion hacks -- i.e. if the type's coercion function |
| 223 | returns other types, then these are allowed as well). Numbers that |
| 224 | have the Py_TPFLAGS_CHECKTYPES flag bit set should check *both* |
| 225 | arguments for proper type and implement the necessary conversions |
| 226 | in the slot functions themselves. */ |
| 227 | |
| 228 | binaryfunc nb_add; |
| 229 | binaryfunc nb_subtract; |
| 230 | binaryfunc nb_multiply; |
| 231 | binaryfunc nb_divide; |
| 232 | binaryfunc nb_remainder; |
| 233 | binaryfunc nb_divmod; |
| 234 | ternaryfunc nb_power; |
| 235 | unaryfunc nb_negative; |
| 236 | unaryfunc nb_positive; |
| 237 | unaryfunc nb_absolute; |
| 238 | inquiry nb_nonzero; |
| 239 | unaryfunc nb_invert; |
| 240 | binaryfunc nb_lshift; |
| 241 | binaryfunc nb_rshift; |
| 242 | binaryfunc nb_and; |
| 243 | binaryfunc nb_xor; |
| 244 | binaryfunc nb_or; |
| 245 | coercion nb_coerce; |
| 246 | unaryfunc nb_int; |
| 247 | unaryfunc nb_long; |
| 248 | unaryfunc nb_float; |
| 249 | unaryfunc nb_oct; |
| 250 | unaryfunc nb_hex; |
| 251 | /* Added in release 2.0 */ |
| 252 | binaryfunc nb_inplace_add; |
| 253 | binaryfunc nb_inplace_subtract; |
| 254 | binaryfunc nb_inplace_multiply; |
| 255 | binaryfunc nb_inplace_divide; |
| 256 | binaryfunc nb_inplace_remainder; |
| 257 | ternaryfunc nb_inplace_power; |
| 258 | binaryfunc nb_inplace_lshift; |
| 259 | binaryfunc nb_inplace_rshift; |
| 260 | binaryfunc nb_inplace_and; |
| 261 | binaryfunc nb_inplace_xor; |
| 262 | binaryfunc nb_inplace_or; |
| 263 | |
| 264 | /* Added in release 2.2 */ |
| 265 | /* The following require the Py_TPFLAGS_HAVE_CLASS flag */ |
| 266 | binaryfunc nb_floor_divide; |
| 267 | binaryfunc nb_true_divide; |
| 268 | binaryfunc nb_inplace_floor_divide; |
| 269 | binaryfunc nb_inplace_true_divide; |
| 270 | |
| 271 | /* Added in release 2.5 */ |
| 272 | unaryfunc nb_index; |
| 273 | } PyNumberMethods; |
| 274 | |
| 275 | typedef struct { |
| 276 | lenfunc sq_length; |
| 277 | binaryfunc sq_concat; |
| 278 | ssizeargfunc sq_repeat; |
| 279 | ssizeargfunc sq_item; |
| 280 | ssizessizeargfunc sq_slice; |
| 281 | ssizeobjargproc sq_ass_item; |
| 282 | ssizessizeobjargproc sq_ass_slice; |
| 283 | objobjproc sq_contains; |
| 284 | /* Added in release 2.0 */ |
| 285 | binaryfunc sq_inplace_concat; |
| 286 | ssizeargfunc sq_inplace_repeat; |
| 287 | } PySequenceMethods; |
| 288 | |
| 289 | typedef struct { |
| 290 | lenfunc mp_length; |
| 291 | binaryfunc mp_subscript; |
| 292 | objobjargproc mp_ass_subscript; |
| 293 | } PyMappingMethods; |
| 294 | |
| 295 | typedef struct { |
| 296 | readbufferproc bf_getreadbuffer; |
| 297 | writebufferproc bf_getwritebuffer; |
| 298 | segcountproc bf_getsegcount; |
| 299 | charbufferproc bf_getcharbuffer; |
| 300 | getbufferproc bf_getbuffer; |
| 301 | releasebufferproc bf_releasebuffer; |
| 302 | } PyBufferProcs; |
| 303 | |
| 304 | |
| 305 | typedef void (*freefunc)(void *); |
| 306 | typedef void (*destructor)(PyObject *); |
| 307 | typedef int (*printfunc)(PyObject *, FILE *, int); |
| 308 | typedef PyObject *(*getattrfunc)(PyObject *, char *); |
| 309 | typedef PyObject *(*getattrofunc)(PyObject *, PyObject *); |
| 310 | typedef int (*setattrfunc)(PyObject *, char *, PyObject *); |
| 311 | typedef int (*setattrofunc)(PyObject *, PyObject *, PyObject *); |
| 312 | typedef int (*cmpfunc)(PyObject *, PyObject *); |
| 313 | typedef PyObject *(*reprfunc)(PyObject *); |
| 314 | typedef long (*hashfunc)(PyObject *); |
| 315 | typedef PyObject *(*richcmpfunc) (PyObject *, PyObject *, int); |
| 316 | typedef PyObject *(*getiterfunc) (PyObject *); |
| 317 | typedef PyObject *(*iternextfunc) (PyObject *); |
| 318 | typedef PyObject *(*descrgetfunc) (PyObject *, PyObject *, PyObject *); |
| 319 | typedef int (*descrsetfunc) (PyObject *, PyObject *, PyObject *); |
| 320 | typedef int (*initproc)(PyObject *, PyObject *, PyObject *); |
| 321 | typedef PyObject *(*newfunc)(struct _typeobject *, PyObject *, PyObject *); |
| 322 | typedef PyObject *(*allocfunc)(struct _typeobject *, Py_ssize_t); |
| 323 | |
| 324 | typedef struct _typeobject { |
| 325 | PyObject_VAR_HEAD |
| 326 | const char *tp_name; /* For printing, in format "<module>.<name>" */ |
| 327 | Py_ssize_t tp_basicsize, tp_itemsize; /* For allocation */ |
| 328 | |
| 329 | /* Methods to implement standard operations */ |
| 330 | |
| 331 | destructor tp_dealloc; |
| 332 | printfunc tp_print; |
| 333 | getattrfunc tp_getattr; |
| 334 | setattrfunc tp_setattr; |
| 335 | cmpfunc tp_compare; |
| 336 | reprfunc tp_repr; |
| 337 | |
| 338 | /* Method suites for standard classes */ |
| 339 | |
| 340 | PyNumberMethods *tp_as_number; |
| 341 | PySequenceMethods *tp_as_sequence; |
| 342 | PyMappingMethods *tp_as_mapping; |
| 343 | |
| 344 | /* More standard operations (here for binary compatibility) */ |
| 345 | |
| 346 | hashfunc tp_hash; |
| 347 | ternaryfunc tp_call; |
| 348 | reprfunc tp_str; |
| 349 | getattrofunc tp_getattro; |
| 350 | setattrofunc tp_setattro; |
| 351 | |
| 352 | /* Functions to access object as input/output buffer */ |
| 353 | PyBufferProcs *tp_as_buffer; |
| 354 | |
| 355 | /* Flags to define presence of optional/expanded features */ |
| 356 | long tp_flags; |
| 357 | |
| 358 | const char *tp_doc; /* Documentation string */ |
| 359 | |
| 360 | /* Assigned meaning in release 2.0 */ |
| 361 | /* call function for all accessible objects */ |
| 362 | traverseproc tp_traverse; |
| 363 | |
| 364 | /* delete references to contained objects */ |
| 365 | inquiry tp_clear; |
| 366 | |
| 367 | /* Assigned meaning in release 2.1 */ |
| 368 | /* rich comparisons */ |
| 369 | richcmpfunc tp_richcompare; |
| 370 | |
| 371 | /* weak reference enabler */ |
| 372 | Py_ssize_t tp_weaklistoffset; |
| 373 | |
| 374 | /* Added in release 2.2 */ |
| 375 | /* Iterators */ |
| 376 | getiterfunc tp_iter; |
| 377 | iternextfunc tp_iternext; |
| 378 | |
| 379 | /* Attribute descriptor and subclassing stuff */ |
| 380 | struct PyMethodDef *tp_methods; |
| 381 | struct PyMemberDef *tp_members; |
| 382 | struct PyGetSetDef *tp_getset; |
| 383 | struct _typeobject *tp_base; |
| 384 | PyObject *tp_dict; |
| 385 | descrgetfunc tp_descr_get; |
| 386 | descrsetfunc tp_descr_set; |
| 387 | Py_ssize_t tp_dictoffset; |
| 388 | initproc tp_init; |
| 389 | allocfunc tp_alloc; |
| 390 | newfunc tp_new; |
| 391 | freefunc tp_free; /* Low-level free-memory routine */ |
| 392 | inquiry tp_is_gc; /* For PyObject_IS_GC */ |
| 393 | PyObject *tp_bases; |
| 394 | PyObject *tp_mro; /* method resolution order */ |
| 395 | PyObject *tp_cache; |
| 396 | PyObject *tp_subclasses; |
| 397 | PyObject *tp_weaklist; |
| 398 | destructor tp_del; |
| 399 | |
| 400 | /* Type attribute cache version tag. Added in version 2.6 */ |
| 401 | unsigned int tp_version_tag; |
| 402 | |
| 403 | #ifdef COUNT_ALLOCS |
| 404 | /* these must be last and never explicitly initialized */ |
| 405 | Py_ssize_t tp_allocs; |
| 406 | Py_ssize_t tp_frees; |
| 407 | Py_ssize_t tp_maxalloc; |
| 408 | struct _typeobject *tp_prev; |
| 409 | struct _typeobject *tp_next; |
| 410 | #endif |
| 411 | } PyTypeObject; |
| 412 | |
| 413 | |
| 414 | /* The *real* layout of a type object when allocated on the heap */ |
| 415 | typedef struct _heaptypeobject { |
| 416 | /* Note: there's a dependency on the order of these members |
| 417 | in slotptr() in typeobject.c . */ |
| 418 | PyTypeObject ht_type; |
| 419 | PyNumberMethods as_number; |
| 420 | PyMappingMethods as_mapping; |
| 421 | PySequenceMethods as_sequence; /* as_sequence comes after as_mapping, |
| 422 | so that the mapping wins when both |
| 423 | the mapping and the sequence define |
| 424 | a given operator (e.g. __getitem__). |
| 425 | see add_operators() in typeobject.c . */ |
| 426 | PyBufferProcs as_buffer; |
| 427 | PyObject *ht_name, *ht_slots; |
| 428 | /* here are optional user slots, followed by the members. */ |
| 429 | } PyHeapTypeObject; |
| 430 | |
| 431 | /* access macro to the members which are floating "behind" the object */ |
| 432 | #define PyHeapType_GET_MEMBERS(etype) \ |
| 433 | ((PyMemberDef *)(((char *)etype) + Py_TYPE(etype)->tp_basicsize)) |
| 434 | |
| 435 | |
| 436 | /* Generic type check */ |
| 437 | PyAPI_FUNC(int) PyType_IsSubtype(PyTypeObject *, PyTypeObject *); |
| 438 | #define PyObject_TypeCheck(ob, tp) \ |
| 439 | (Py_TYPE(ob) == (tp) || PyType_IsSubtype(Py_TYPE(ob), (tp))) |
| 440 | |
| 441 | PyAPI_DATA(PyTypeObject) PyType_Type; /* built-in 'type' */ |
| 442 | PyAPI_DATA(PyTypeObject) PyBaseObject_Type; /* built-in 'object' */ |
| 443 | PyAPI_DATA(PyTypeObject) PySuper_Type; /* built-in 'super' */ |
| 444 | |
| 445 | #define PyType_Check(op) \ |
| 446 | PyType_FastSubclass(Py_TYPE(op), Py_TPFLAGS_TYPE_SUBCLASS) |
| 447 | #define PyType_CheckExact(op) (Py_TYPE(op) == &PyType_Type) |
| 448 | |
| 449 | PyAPI_FUNC(int) PyType_Ready(PyTypeObject *); |
| 450 | PyAPI_FUNC(PyObject *) PyType_GenericAlloc(PyTypeObject *, Py_ssize_t); |
| 451 | PyAPI_FUNC(PyObject *) PyType_GenericNew(PyTypeObject *, |
| 452 | PyObject *, PyObject *); |
| 453 | PyAPI_FUNC(PyObject *) _PyType_Lookup(PyTypeObject *, PyObject *); |
| 454 | PyAPI_FUNC(PyObject *) _PyObject_LookupSpecial(PyObject *, char *, PyObject **); |
| 455 | PyAPI_FUNC(unsigned int) PyType_ClearCache(void); |
| 456 | PyAPI_FUNC(void) PyType_Modified(PyTypeObject *); |
| 457 | |
| 458 | /* Generic operations on objects */ |
| 459 | PyAPI_FUNC(int) PyObject_Print(PyObject *, FILE *, int); |
| 460 | PyAPI_FUNC(void) _PyObject_Dump(PyObject *); |
| 461 | PyAPI_FUNC(PyObject *) PyObject_Repr(PyObject *); |
| 462 | PyAPI_FUNC(PyObject *) _PyObject_Str(PyObject *); |
| 463 | PyAPI_FUNC(PyObject *) PyObject_Str(PyObject *); |
| 464 | #define PyObject_Bytes PyObject_Str |
| 465 | #ifdef Py_USING_UNICODE |
| 466 | PyAPI_FUNC(PyObject *) PyObject_Unicode(PyObject *); |
| 467 | #endif |
| 468 | PyAPI_FUNC(int) PyObject_Compare(PyObject *, PyObject *); |
| 469 | PyAPI_FUNC(PyObject *) PyObject_RichCompare(PyObject *, PyObject *, int); |
| 470 | PyAPI_FUNC(int) PyObject_RichCompareBool(PyObject *, PyObject *, int); |
| 471 | PyAPI_FUNC(PyObject *) PyObject_GetAttrString(PyObject *, const char *); |
| 472 | PyAPI_FUNC(int) PyObject_SetAttrString(PyObject *, const char *, PyObject *); |
| 473 | PyAPI_FUNC(int) PyObject_HasAttrString(PyObject *, const char *); |
| 474 | PyAPI_FUNC(PyObject *) PyObject_GetAttr(PyObject *, PyObject *); |
| 475 | PyAPI_FUNC(int) PyObject_SetAttr(PyObject *, PyObject *, PyObject *); |
| 476 | PyAPI_FUNC(int) PyObject_HasAttr(PyObject *, PyObject *); |
| 477 | PyAPI_FUNC(PyObject **) _PyObject_GetDictPtr(PyObject *); |
| 478 | PyAPI_FUNC(PyObject *) PyObject_SelfIter(PyObject *); |
| 479 | PyAPI_FUNC(PyObject *) _PyObject_NextNotImplemented(PyObject *); |
| 480 | PyAPI_FUNC(PyObject *) PyObject_GenericGetAttr(PyObject *, PyObject *); |
| 481 | PyAPI_FUNC(int) PyObject_GenericSetAttr(PyObject *, |
| 482 | PyObject *, PyObject *); |
| 483 | PyAPI_FUNC(long) PyObject_Hash(PyObject *); |
| 484 | PyAPI_FUNC(long) PyObject_HashNotImplemented(PyObject *); |
| 485 | PyAPI_FUNC(int) PyObject_IsTrue(PyObject *); |
| 486 | PyAPI_FUNC(int) PyObject_Not(PyObject *); |
| 487 | PyAPI_FUNC(int) PyCallable_Check(PyObject *); |
| 488 | PyAPI_FUNC(int) PyNumber_Coerce(PyObject **, PyObject **); |
| 489 | PyAPI_FUNC(int) PyNumber_CoerceEx(PyObject **, PyObject **); |
| 490 | |
| 491 | PyAPI_FUNC(void) PyObject_ClearWeakRefs(PyObject *); |
| 492 | |
| 493 | /* A slot function whose address we need to compare */ |
| 494 | extern int _PyObject_SlotCompare(PyObject *, PyObject *); |
| 495 | /* Same as PyObject_Generic{Get,Set}Attr, but passing the attributes |
| 496 | dict as the last parameter. */ |
| 497 | PyAPI_FUNC(PyObject *) |
| 498 | _PyObject_GenericGetAttrWithDict(PyObject *, PyObject *, PyObject *); |
| 499 | PyAPI_FUNC(int) |
| 500 | _PyObject_GenericSetAttrWithDict(PyObject *, PyObject *, |
| 501 | PyObject *, PyObject *); |
| 502 | |
| 503 | |
| 504 | /* PyObject_Dir(obj) acts like Python __builtin__.dir(obj), returning a |
| 505 | list of strings. PyObject_Dir(NULL) is like __builtin__.dir(), |
| 506 | returning the names of the current locals. In this case, if there are |
| 507 | no current locals, NULL is returned, and PyErr_Occurred() is false. |
| 508 | */ |
| 509 | PyAPI_FUNC(PyObject *) PyObject_Dir(PyObject *); |
| 510 | |
| 511 | |
| 512 | /* Helpers for printing recursive container types */ |
| 513 | PyAPI_FUNC(int) Py_ReprEnter(PyObject *); |
| 514 | PyAPI_FUNC(void) Py_ReprLeave(PyObject *); |
| 515 | |
| 516 | /* Helpers for hash functions */ |
| 517 | PyAPI_FUNC(long) _Py_HashDouble(double); |
| 518 | PyAPI_FUNC(long) _Py_HashPointer(void*); |
| 519 | |
| 520 | typedef struct { |
| 521 | long prefix; |
| 522 | long suffix; |
| 523 | } _Py_HashSecret_t; |
| 524 | PyAPI_DATA(_Py_HashSecret_t) _Py_HashSecret; |
| 525 | |
| 526 | #ifdef Py_DEBUG |
| 527 | PyAPI_DATA(int) _Py_HashSecret_Initialized; |
| 528 | #endif |
| 529 | |
| 530 | /* Helper for passing objects to printf and the like */ |
| 531 | #define PyObject_REPR(obj) PyString_AS_STRING(PyObject_Repr(obj)) |
| 532 | |
| 533 | /* Flag bits for printing: */ |
| 534 | #define Py_PRINT_RAW 1 /* No string quotes etc. */ |
| 535 | |
| 536 | /* |
| 537 | `Type flags (tp_flags) |
| 538 | |
| 539 | These flags are used to extend the type structure in a backwards-compatible |
| 540 | fashion. Extensions can use the flags to indicate (and test) when a given |
| 541 | type structure contains a new feature. The Python core will use these when |
| 542 | introducing new functionality between major revisions (to avoid mid-version |
| 543 | changes in the PYTHON_API_VERSION). |
| 544 | |
| 545 | Arbitration of the flag bit positions will need to be coordinated among |
| 546 | all extension writers who publically release their extensions (this will |
| 547 | be fewer than you might expect!).. |
| 548 | |
| 549 | Python 1.5.2 introduced the bf_getcharbuffer slot into PyBufferProcs. |
| 550 | |
| 551 | Type definitions should use Py_TPFLAGS_DEFAULT for their tp_flags value. |
| 552 | |
| 553 | Code can use PyType_HasFeature(type_ob, flag_value) to test whether the |
| 554 | given type object has a specified feature. |
| 555 | |
| 556 | NOTE: when building the core, Py_TPFLAGS_DEFAULT includes |
| 557 | Py_TPFLAGS_HAVE_VERSION_TAG; outside the core, it doesn't. This is so |
| 558 | that extensions that modify tp_dict of their own types directly don't |
| 559 | break, since this was allowed in 2.5. In 3.0 they will have to |
| 560 | manually remove this flag though! |
| 561 | */ |
| 562 | |
| 563 | /* PyBufferProcs contains bf_getcharbuffer */ |
| 564 | #define Py_TPFLAGS_HAVE_GETCHARBUFFER (1L<<0) |
| 565 | |
| 566 | /* PySequenceMethods contains sq_contains */ |
| 567 | #define Py_TPFLAGS_HAVE_SEQUENCE_IN (1L<<1) |
| 568 | |
| 569 | /* This is here for backwards compatibility. Extensions that use the old GC |
| 570 | * API will still compile but the objects will not be tracked by the GC. */ |
| 571 | #define Py_TPFLAGS_GC 0 /* used to be (1L<<2) */ |
| 572 | |
| 573 | /* PySequenceMethods and PyNumberMethods contain in-place operators */ |
| 574 | #define Py_TPFLAGS_HAVE_INPLACEOPS (1L<<3) |
| 575 | |
| 576 | /* PyNumberMethods do their own coercion */ |
| 577 | #define Py_TPFLAGS_CHECKTYPES (1L<<4) |
| 578 | |
| 579 | /* tp_richcompare is defined */ |
| 580 | #define Py_TPFLAGS_HAVE_RICHCOMPARE (1L<<5) |
| 581 | |
| 582 | /* Objects which are weakly referencable if their tp_weaklistoffset is >0 */ |
| 583 | #define Py_TPFLAGS_HAVE_WEAKREFS (1L<<6) |
| 584 | |
| 585 | /* tp_iter is defined */ |
| 586 | #define Py_TPFLAGS_HAVE_ITER (1L<<7) |
| 587 | |
| 588 | /* New members introduced by Python 2.2 exist */ |
| 589 | #define Py_TPFLAGS_HAVE_CLASS (1L<<8) |
| 590 | |
| 591 | /* Set if the type object is dynamically allocated */ |
| 592 | #define Py_TPFLAGS_HEAPTYPE (1L<<9) |
| 593 | |
| 594 | /* Set if the type allows subclassing */ |
| 595 | #define Py_TPFLAGS_BASETYPE (1L<<10) |
| 596 | |
| 597 | /* Set if the type is 'ready' -- fully initialized */ |
| 598 | #define Py_TPFLAGS_READY (1L<<12) |
| 599 | |
| 600 | /* Set while the type is being 'readied', to prevent recursive ready calls */ |
| 601 | #define Py_TPFLAGS_READYING (1L<<13) |
| 602 | |
| 603 | /* Objects support garbage collection (see objimp.h) */ |
| 604 | #define Py_TPFLAGS_HAVE_GC (1L<<14) |
| 605 | |
| 606 | /* These two bits are preserved for Stackless Python, next after this is 17 */ |
| 607 | #ifdef STACKLESS |
| 608 | #define Py_TPFLAGS_HAVE_STACKLESS_EXTENSION (3L<<15) |
| 609 | #else |
| 610 | #define Py_TPFLAGS_HAVE_STACKLESS_EXTENSION 0 |
| 611 | #endif |
| 612 | |
| 613 | /* Objects support nb_index in PyNumberMethods */ |
| 614 | #define Py_TPFLAGS_HAVE_INDEX (1L<<17) |
| 615 | |
| 616 | /* Objects support type attribute cache */ |
| 617 | #define Py_TPFLAGS_HAVE_VERSION_TAG (1L<<18) |
| 618 | #define Py_TPFLAGS_VALID_VERSION_TAG (1L<<19) |
| 619 | |
| 620 | /* Type is abstract and cannot be instantiated */ |
| 621 | #define Py_TPFLAGS_IS_ABSTRACT (1L<<20) |
| 622 | |
| 623 | /* Has the new buffer protocol */ |
| 624 | #define Py_TPFLAGS_HAVE_NEWBUFFER (1L<<21) |
| 625 | |
| 626 | /* These flags are used to determine if a type is a subclass. */ |
| 627 | #define Py_TPFLAGS_INT_SUBCLASS (1L<<23) |
| 628 | #define Py_TPFLAGS_LONG_SUBCLASS (1L<<24) |
| 629 | #define Py_TPFLAGS_LIST_SUBCLASS (1L<<25) |
| 630 | #define Py_TPFLAGS_TUPLE_SUBCLASS (1L<<26) |
| 631 | #define Py_TPFLAGS_STRING_SUBCLASS (1L<<27) |
| 632 | #define Py_TPFLAGS_UNICODE_SUBCLASS (1L<<28) |
| 633 | #define Py_TPFLAGS_DICT_SUBCLASS (1L<<29) |
| 634 | #define Py_TPFLAGS_BASE_EXC_SUBCLASS (1L<<30) |
| 635 | #define Py_TPFLAGS_TYPE_SUBCLASS (1L<<31) |
| 636 | |
| 637 | #define Py_TPFLAGS_DEFAULT_EXTERNAL ( \ |
| 638 | Py_TPFLAGS_HAVE_GETCHARBUFFER | \ |
| 639 | Py_TPFLAGS_HAVE_SEQUENCE_IN | \ |
| 640 | Py_TPFLAGS_HAVE_INPLACEOPS | \ |
| 641 | Py_TPFLAGS_HAVE_RICHCOMPARE | \ |
| 642 | Py_TPFLAGS_HAVE_WEAKREFS | \ |
| 643 | Py_TPFLAGS_HAVE_ITER | \ |
| 644 | Py_TPFLAGS_HAVE_CLASS | \ |
| 645 | Py_TPFLAGS_HAVE_STACKLESS_EXTENSION | \ |
| 646 | Py_TPFLAGS_HAVE_INDEX | \ |
| 647 | 0) |
| 648 | #define Py_TPFLAGS_DEFAULT_CORE (Py_TPFLAGS_DEFAULT_EXTERNAL | \ |
| 649 | Py_TPFLAGS_HAVE_VERSION_TAG) |
| 650 | |
| 651 | #ifdef Py_BUILD_CORE |
| 652 | #define Py_TPFLAGS_DEFAULT Py_TPFLAGS_DEFAULT_CORE |
| 653 | #else |
| 654 | #define Py_TPFLAGS_DEFAULT Py_TPFLAGS_DEFAULT_EXTERNAL |
| 655 | #endif |
| 656 | |
| 657 | #define PyType_HasFeature(t,f) (((t)->tp_flags & (f)) != 0) |
| 658 | #define PyType_FastSubclass(t,f) PyType_HasFeature(t,f) |
| 659 | |
| 660 | |
| 661 | /* |
| 662 | The macros Py_INCREF(op) and Py_DECREF(op) are used to increment or decrement |
| 663 | reference counts. Py_DECREF calls the object's deallocator function when |
| 664 | the refcount falls to 0; for |
| 665 | objects that don't contain references to other objects or heap memory |
| 666 | this can be the standard function free(). Both macros can be used |
| 667 | wherever a void expression is allowed. The argument must not be a |
| 668 | NULL pointer. If it may be NULL, use Py_XINCREF/Py_XDECREF instead. |
| 669 | The macro _Py_NewReference(op) initialize reference counts to 1, and |
| 670 | in special builds (Py_REF_DEBUG, Py_TRACE_REFS) performs additional |
| 671 | bookkeeping appropriate to the special build. |
| 672 | |
| 673 | We assume that the reference count field can never overflow; this can |
| 674 | be proven when the size of the field is the same as the pointer size, so |
| 675 | we ignore the possibility. Provided a C int is at least 32 bits (which |
| 676 | is implicitly assumed in many parts of this code), that's enough for |
| 677 | about 2**31 references to an object. |
| 678 | |
| 679 | XXX The following became out of date in Python 2.2, but I'm not sure |
| 680 | XXX what the full truth is now. Certainly, heap-allocated type objects |
| 681 | XXX can and should be deallocated. |
| 682 | Type objects should never be deallocated; the type pointer in an object |
| 683 | is not considered to be a reference to the type object, to save |
| 684 | complications in the deallocation function. (This is actually a |
| 685 | decision that's up to the implementer of each new type so if you want, |
| 686 | you can count such references to the type object.) |
| 687 | |
| 688 | *** WARNING*** The Py_DECREF macro must have a side-effect-free argument |
| 689 | since it may evaluate its argument multiple times. (The alternative |
| 690 | would be to mace it a proper function or assign it to a global temporary |
| 691 | variable first, both of which are slower; and in a multi-threaded |
| 692 | environment the global variable trick is not safe.) |
| 693 | */ |
| 694 | |
| 695 | /* First define a pile of simple helper macros, one set per special |
| 696 | * build symbol. These either expand to the obvious things, or to |
| 697 | * nothing at all when the special mode isn't in effect. The main |
| 698 | * macros can later be defined just once then, yet expand to different |
| 699 | * things depending on which special build options are and aren't in effect. |
| 700 | * Trust me <wink>: while painful, this is 20x easier to understand than, |
| 701 | * e.g, defining _Py_NewReference five different times in a maze of nested |
| 702 | * #ifdefs (we used to do that -- it was impenetrable). |
| 703 | */ |
| 704 | #ifdef Py_REF_DEBUG |
| 705 | PyAPI_DATA(Py_ssize_t) _Py_RefTotal; |
| 706 | PyAPI_FUNC(void) _Py_NegativeRefcount(const char *fname, |
| 707 | int lineno, PyObject *op); |
| 708 | PyAPI_FUNC(PyObject *) _PyDict_Dummy(void); |
| 709 | PyAPI_FUNC(PyObject *) _PySet_Dummy(void); |
| 710 | PyAPI_FUNC(Py_ssize_t) _Py_GetRefTotal(void); |
| 711 | #define _Py_INC_REFTOTAL _Py_RefTotal++ |
| 712 | #define _Py_DEC_REFTOTAL _Py_RefTotal-- |
| 713 | #define _Py_REF_DEBUG_COMMA , |
| 714 | #define _Py_CHECK_REFCNT(OP) \ |
| 715 | { if (((PyObject*)OP)->ob_refcnt < 0) \ |
| 716 | _Py_NegativeRefcount(__FILE__, __LINE__, \ |
| 717 | (PyObject *)(OP)); \ |
| 718 | } |
| 719 | #else |
| 720 | #define _Py_INC_REFTOTAL |
| 721 | #define _Py_DEC_REFTOTAL |
| 722 | #define _Py_REF_DEBUG_COMMA |
| 723 | #define _Py_CHECK_REFCNT(OP) /* a semicolon */; |
| 724 | #endif /* Py_REF_DEBUG */ |
| 725 | |
| 726 | #ifdef COUNT_ALLOCS |
| 727 | PyAPI_FUNC(void) inc_count(PyTypeObject *); |
| 728 | PyAPI_FUNC(void) dec_count(PyTypeObject *); |
| 729 | #define _Py_INC_TPALLOCS(OP) inc_count(Py_TYPE(OP)) |
| 730 | #define _Py_INC_TPFREES(OP) dec_count(Py_TYPE(OP)) |
| 731 | #define _Py_DEC_TPFREES(OP) Py_TYPE(OP)->tp_frees-- |
| 732 | #define _Py_COUNT_ALLOCS_COMMA , |
| 733 | #else |
| 734 | #define _Py_INC_TPALLOCS(OP) |
| 735 | #define _Py_INC_TPFREES(OP) |
| 736 | #define _Py_DEC_TPFREES(OP) |
| 737 | #define _Py_COUNT_ALLOCS_COMMA |
| 738 | #endif /* COUNT_ALLOCS */ |
| 739 | |
| 740 | #ifdef Py_TRACE_REFS |
| 741 | /* Py_TRACE_REFS is such major surgery that we call external routines. */ |
| 742 | PyAPI_FUNC(void) _Py_NewReference(PyObject *); |
| 743 | PyAPI_FUNC(void) _Py_ForgetReference(PyObject *); |
| 744 | PyAPI_FUNC(void) _Py_Dealloc(PyObject *); |
| 745 | PyAPI_FUNC(void) _Py_PrintReferences(FILE *); |
| 746 | PyAPI_FUNC(void) _Py_PrintReferenceAddresses(FILE *); |
| 747 | PyAPI_FUNC(void) _Py_AddToAllObjects(PyObject *, int force); |
| 748 | |
| 749 | #else |
| 750 | /* Without Py_TRACE_REFS, there's little enough to do that we expand code |
| 751 | * inline. |
| 752 | */ |
| 753 | #define _Py_NewReference(op) ( \ |
| 754 | _Py_INC_TPALLOCS(op) _Py_COUNT_ALLOCS_COMMA \ |
| 755 | _Py_INC_REFTOTAL _Py_REF_DEBUG_COMMA \ |
| 756 | Py_REFCNT(op) = 1) |
| 757 | |
| 758 | #define _Py_ForgetReference(op) _Py_INC_TPFREES(op) |
| 759 | |
| 760 | #define _Py_Dealloc(op) ( \ |
| 761 | _Py_INC_TPFREES(op) _Py_COUNT_ALLOCS_COMMA \ |
| 762 | (*Py_TYPE(op)->tp_dealloc)((PyObject *)(op))) |
| 763 | #endif /* !Py_TRACE_REFS */ |
| 764 | |
| 765 | #define Py_INCREF(op) ( \ |
| 766 | _Py_INC_REFTOTAL _Py_REF_DEBUG_COMMA \ |
| 767 | ((PyObject*)(op))->ob_refcnt++) |
| 768 | |
| 769 | #define Py_DECREF(op) \ |
| 770 | do { \ |
| 771 | if (_Py_DEC_REFTOTAL _Py_REF_DEBUG_COMMA \ |
| 772 | --((PyObject*)(op))->ob_refcnt != 0) \ |
| 773 | _Py_CHECK_REFCNT(op) \ |
| 774 | else \ |
| 775 | _Py_Dealloc((PyObject *)(op)); \ |
| 776 | } while (0) |
| 777 | |
| 778 | /* Safely decref `op` and set `op` to NULL, especially useful in tp_clear |
| 779 | * and tp_dealloc implementatons. |
| 780 | * |
| 781 | * Note that "the obvious" code can be deadly: |
| 782 | * |
| 783 | * Py_XDECREF(op); |
| 784 | * op = NULL; |
| 785 | * |
| 786 | * Typically, `op` is something like self->containee, and `self` is done |
| 787 | * using its `containee` member. In the code sequence above, suppose |
| 788 | * `containee` is non-NULL with a refcount of 1. Its refcount falls to |
| 789 | * 0 on the first line, which can trigger an arbitrary amount of code, |
| 790 | * possibly including finalizers (like __del__ methods or weakref callbacks) |
| 791 | * coded in Python, which in turn can release the GIL and allow other threads |
| 792 | * to run, etc. Such code may even invoke methods of `self` again, or cause |
| 793 | * cyclic gc to trigger, but-- oops! --self->containee still points to the |
| 794 | * object being torn down, and it may be in an insane state while being torn |
| 795 | * down. This has in fact been a rich historic source of miserable (rare & |
| 796 | * hard-to-diagnose) segfaulting (and other) bugs. |
| 797 | * |
| 798 | * The safe way is: |
| 799 | * |
| 800 | * Py_CLEAR(op); |
| 801 | * |
| 802 | * That arranges to set `op` to NULL _before_ decref'ing, so that any code |
| 803 | * triggered as a side-effect of `op` getting torn down no longer believes |
| 804 | * `op` points to a valid object. |
| 805 | * |
| 806 | * There are cases where it's safe to use the naive code, but they're brittle. |
| 807 | * For example, if `op` points to a Python integer, you know that destroying |
| 808 | * one of those can't cause problems -- but in part that relies on that |
| 809 | * Python integers aren't currently weakly referencable. Best practice is |
| 810 | * to use Py_CLEAR() even if you can't think of a reason for why you need to. |
| 811 | */ |
| 812 | #define Py_CLEAR(op) \ |
| 813 | do { \ |
| 814 | if (op) { \ |
| 815 | PyObject *_py_tmp = (PyObject *)(op); \ |
| 816 | (op) = NULL; \ |
| 817 | Py_DECREF(_py_tmp); \ |
| 818 | } \ |
| 819 | } while (0) |
| 820 | |
| 821 | /* Macros to use in case the object pointer may be NULL: */ |
| 822 | #define Py_XINCREF(op) do { if ((op) == NULL) ; else Py_INCREF(op); } while (0) |
| 823 | #define Py_XDECREF(op) do { if ((op) == NULL) ; else Py_DECREF(op); } while (0) |
| 824 | |
| 825 | /* |
| 826 | These are provided as conveniences to Python runtime embedders, so that |
| 827 | they can have object code that is not dependent on Python compilation flags. |
| 828 | */ |
| 829 | PyAPI_FUNC(void) Py_IncRef(PyObject *); |
| 830 | PyAPI_FUNC(void) Py_DecRef(PyObject *); |
| 831 | |
| 832 | /* |
| 833 | _Py_NoneStruct is an object of undefined type which can be used in contexts |
| 834 | where NULL (nil) is not suitable (since NULL often means 'error'). |
| 835 | |
| 836 | Don't forget to apply Py_INCREF() when returning this value!!! |
| 837 | */ |
| 838 | PyAPI_DATA(PyObject) _Py_NoneStruct; /* Don't use this directly */ |
| 839 | #define Py_None (&_Py_NoneStruct) |
| 840 | |
| 841 | /* Macro for returning Py_None from a function */ |
| 842 | #define Py_RETURN_NONE return Py_INCREF(Py_None), Py_None |
| 843 | |
| 844 | /* |
| 845 | Py_NotImplemented is a singleton used to signal that an operation is |
| 846 | not implemented for a given type combination. |
| 847 | */ |
| 848 | PyAPI_DATA(PyObject) _Py_NotImplementedStruct; /* Don't use this directly */ |
| 849 | #define Py_NotImplemented (&_Py_NotImplementedStruct) |
| 850 | |
| 851 | /* Rich comparison opcodes */ |
| 852 | #define Py_LT 0 |
| 853 | #define Py_LE 1 |
| 854 | #define Py_EQ 2 |
| 855 | #define Py_NE 3 |
| 856 | #define Py_GT 4 |
| 857 | #define Py_GE 5 |
| 858 | |
| 859 | /* Maps Py_LT to Py_GT, ..., Py_GE to Py_LE. |
| 860 | * Defined in object.c. |
| 861 | */ |
| 862 | PyAPI_DATA(int) _Py_SwappedOp[]; |
| 863 | |
| 864 | /* |
| 865 | Define staticforward and statichere for source compatibility with old |
| 866 | C extensions. |
| 867 | |
| 868 | The staticforward define was needed to support certain broken C |
| 869 | compilers (notably SCO ODT 3.0, perhaps early AIX as well) botched the |
| 870 | static keyword when it was used with a forward declaration of a static |
| 871 | initialized structure. Standard C allows the forward declaration with |
| 872 | static, and we've decided to stop catering to broken C compilers. |
| 873 | (In fact, we expect that the compilers are all fixed eight years later.) |
| 874 | */ |
| 875 | |
| 876 | #define staticforward static |
| 877 | #define statichere static |
| 878 | |
| 879 | |
| 880 | /* |
| 881 | More conventions |
| 882 | ================ |
| 883 | |
| 884 | Argument Checking |
| 885 | ----------------- |
| 886 | |
| 887 | Functions that take objects as arguments normally don't check for nil |
| 888 | arguments, but they do check the type of the argument, and return an |
| 889 | error if the function doesn't apply to the type. |
| 890 | |
| 891 | Failure Modes |
| 892 | ------------- |
| 893 | |
| 894 | Functions may fail for a variety of reasons, including running out of |
| 895 | memory. This is communicated to the caller in two ways: an error string |
| 896 | is set (see errors.h), and the function result differs: functions that |
| 897 | normally return a pointer return NULL for failure, functions returning |
| 898 | an integer return -1 (which could be a legal return value too!), and |
| 899 | other functions return 0 for success and -1 for failure. |
| 900 | Callers should always check for errors before using the result. If |
| 901 | an error was set, the caller must either explicitly clear it, or pass |
| 902 | the error on to its caller. |
| 903 | |
| 904 | Reference Counts |
| 905 | ---------------- |
| 906 | |
| 907 | It takes a while to get used to the proper usage of reference counts. |
| 908 | |
| 909 | Functions that create an object set the reference count to 1; such new |
| 910 | objects must be stored somewhere or destroyed again with Py_DECREF(). |
| 911 | Some functions that 'store' objects, such as PyTuple_SetItem() and |
| 912 | PyList_SetItem(), |
| 913 | don't increment the reference count of the object, since the most |
| 914 | frequent use is to store a fresh object. Functions that 'retrieve' |
| 915 | objects, such as PyTuple_GetItem() and PyDict_GetItemString(), also |
| 916 | don't increment |
| 917 | the reference count, since most frequently the object is only looked at |
| 918 | quickly. Thus, to retrieve an object and store it again, the caller |
| 919 | must call Py_INCREF() explicitly. |
| 920 | |
| 921 | NOTE: functions that 'consume' a reference count, like |
| 922 | PyList_SetItem(), consume the reference even if the object wasn't |
| 923 | successfully stored, to simplify error handling. |
| 924 | |
| 925 | It seems attractive to make other functions that take an object as |
| 926 | argument consume a reference count; however, this may quickly get |
| 927 | confusing (even the current practice is already confusing). Consider |
| 928 | it carefully, it may save lots of calls to Py_INCREF() and Py_DECREF() at |
| 929 | times. |
| 930 | */ |
| 931 | |
| 932 | |
| 933 | /* Trashcan mechanism, thanks to Christian Tismer. |
| 934 | |
| 935 | When deallocating a container object, it's possible to trigger an unbounded |
| 936 | chain of deallocations, as each Py_DECREF in turn drops the refcount on "the |
| 937 | next" object in the chain to 0. This can easily lead to stack faults, and |
| 938 | especially in threads (which typically have less stack space to work with). |
| 939 | |
| 940 | A container object that participates in cyclic gc can avoid this by |
| 941 | bracketing the body of its tp_dealloc function with a pair of macros: |
| 942 | |
| 943 | static void |
| 944 | mytype_dealloc(mytype *p) |
| 945 | { |
| 946 | ... declarations go here ... |
| 947 | |
| 948 | PyObject_GC_UnTrack(p); // must untrack first |
| 949 | Py_TRASHCAN_SAFE_BEGIN(p) |
| 950 | ... The body of the deallocator goes here, including all calls ... |
| 951 | ... to Py_DECREF on contained objects. ... |
| 952 | Py_TRASHCAN_SAFE_END(p) |
| 953 | } |
| 954 | |
| 955 | CAUTION: Never return from the middle of the body! If the body needs to |
| 956 | "get out early", put a label immediately before the Py_TRASHCAN_SAFE_END |
| 957 | call, and goto it. Else the call-depth counter (see below) will stay |
| 958 | above 0 forever, and the trashcan will never get emptied. |
| 959 | |
| 960 | How it works: The BEGIN macro increments a call-depth counter. So long |
| 961 | as this counter is small, the body of the deallocator is run directly without |
| 962 | further ado. But if the counter gets large, it instead adds p to a list of |
| 963 | objects to be deallocated later, skips the body of the deallocator, and |
| 964 | resumes execution after the END macro. The tp_dealloc routine then returns |
| 965 | without deallocating anything (and so unbounded call-stack depth is avoided). |
| 966 | |
| 967 | When the call stack finishes unwinding again, code generated by the END macro |
| 968 | notices this, and calls another routine to deallocate all the objects that |
| 969 | may have been added to the list of deferred deallocations. In effect, a |
| 970 | chain of N deallocations is broken into N / PyTrash_UNWIND_LEVEL pieces, |
| 971 | with the call stack never exceeding a depth of PyTrash_UNWIND_LEVEL. |
| 972 | */ |
| 973 | |
| 974 | /* This is the old private API, invoked by the macros before 2.7.4. |
| 975 | Kept for binary compatibility of extensions. */ |
| 976 | PyAPI_FUNC(void) _PyTrash_deposit_object(PyObject*); |
| 977 | PyAPI_FUNC(void) _PyTrash_destroy_chain(void); |
| 978 | PyAPI_DATA(int) _PyTrash_delete_nesting; |
| 979 | PyAPI_DATA(PyObject *) _PyTrash_delete_later; |
| 980 | |
| 981 | /* The new thread-safe private API, invoked by the macros below. */ |
| 982 | PyAPI_FUNC(void) _PyTrash_thread_deposit_object(PyObject*); |
| 983 | PyAPI_FUNC(void) _PyTrash_thread_destroy_chain(void); |
| 984 | |
| 985 | #define PyTrash_UNWIND_LEVEL 50 |
| 986 | |
| 987 | /* Note the workaround for when the thread state is NULL (issue #17703) */ |
| 988 | #define Py_TRASHCAN_SAFE_BEGIN(op) \ |
| 989 | do { \ |
| 990 | PyThreadState *_tstate = PyThreadState_GET(); \ |
| 991 | if (!_tstate || \ |
| 992 | _tstate->trash_delete_nesting < PyTrash_UNWIND_LEVEL) { \ |
| 993 | if (_tstate) \ |
| 994 | ++_tstate->trash_delete_nesting; |
| 995 | /* The body of the deallocator is here. */ |
| 996 | #define Py_TRASHCAN_SAFE_END(op) \ |
| 997 | if (_tstate) { \ |
| 998 | --_tstate->trash_delete_nesting; \ |
| 999 | if (_tstate->trash_delete_later \ |
| 1000 | && _tstate->trash_delete_nesting <= 0) \ |
| 1001 | _PyTrash_thread_destroy_chain(); \ |
| 1002 | } \ |
| 1003 | } \ |
| 1004 | else \ |
| 1005 | _PyTrash_thread_deposit_object((PyObject*)op); \ |
| 1006 | } while (0); |
| 1007 | |
| 1008 | #ifdef __cplusplus |
| 1009 | } |
| 1010 | #endif |
| 1011 | #endif /* !Py_OBJECT_H */ |