Tim Peters | 8b078f9 | 2002-04-28 04:11:46 +0000 | [diff] [blame] | 1 | /* The PyObject_ memory family: high-level object memory interfaces. |
| 2 | See pymem.h for the low-level PyMem_ family. |
| 3 | */ |
Guido van Rossum | f70e43a | 1991-02-19 12:39:46 +0000 | [diff] [blame] | 4 | |
Fred Drake | 3cf4d2b | 2000-07-09 00:55:06 +0000 | [diff] [blame] | 5 | #ifndef Py_OBJIMPL_H |
| 6 | #define Py_OBJIMPL_H |
Peter Schneider-Kamp | 25f6894 | 2000-07-31 22:19:30 +0000 | [diff] [blame] | 7 | |
| 8 | #include "pymem.h" |
| 9 | |
Fred Drake | 3cf4d2b | 2000-07-09 00:55:06 +0000 | [diff] [blame] | 10 | #ifdef __cplusplus |
| 11 | extern "C" { |
| 12 | #endif |
| 13 | |
Tim Peters | 8b078f9 | 2002-04-28 04:11:46 +0000 | [diff] [blame] | 14 | /* BEWARE: |
| 15 | |
| 16 | Each interface exports both functions and macros. Extension modules should |
| 17 | use the functions, to ensure binary compatibility across Python versions. |
| 18 | Because the Python implementation is free to change internal details, and |
| 19 | the macros may (or may not) expose details for speed, if you do use the |
| 20 | macros you must recompile your extensions with each Python release. |
| 21 | |
| 22 | Never mix calls to PyObject_ memory functions with calls to the platform |
| 23 | malloc/realloc/ calloc/free, or with calls to PyMem_. |
| 24 | */ |
| 25 | |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 26 | /* |
Guido van Rossum | b18618d | 2000-05-03 23:44:39 +0000 | [diff] [blame] | 27 | Functions and macros for modules that implement new object types. |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 28 | |
Tim Peters | 8b078f9 | 2002-04-28 04:11:46 +0000 | [diff] [blame] | 29 | - PyObject_New(type, typeobj) allocates memory for a new object of the given |
| 30 | type, and initializes part of it. 'type' must be the C structure type used |
| 31 | to represent the object, and 'typeobj' the address of the corresponding |
| 32 | type object. Reference count and type pointer are filled in; the rest of |
| 33 | the bytes of the object are *undefined*! The resulting expression type is |
| 34 | 'type *'. The size of the object is determined by the tp_basicsize field |
| 35 | of the type object. |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 36 | |
Tim Peters | 8b078f9 | 2002-04-28 04:11:46 +0000 | [diff] [blame] | 37 | - PyObject_NewVar(type, typeobj, n) is similar but allocates a variable-size |
| 38 | object with room for n items. In addition to the refcount and type pointer |
| 39 | fields, this also fills in the ob_size field. |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 40 | |
Tim Peters | 8b078f9 | 2002-04-28 04:11:46 +0000 | [diff] [blame] | 41 | - PyObject_Del(op) releases the memory allocated for an object. It does not |
| 42 | run a destructor -- it only frees the memory. PyObject_Free is identical. |
Guido van Rossum | b18618d | 2000-05-03 23:44:39 +0000 | [diff] [blame] | 43 | |
Tim Peters | 8b078f9 | 2002-04-28 04:11:46 +0000 | [diff] [blame] | 44 | - PyObject_Init(op, typeobj) and PyObject_InitVar(op, typeobj, n) don't |
| 45 | allocate memory. Instead of a 'type' parameter, they take a pointer to a |
| 46 | new object (allocated by an arbitrary allocator), and initialize its object |
| 47 | header fields. |
Guido van Rossum | b18618d | 2000-05-03 23:44:39 +0000 | [diff] [blame] | 48 | |
Tim Peters | 8b078f9 | 2002-04-28 04:11:46 +0000 | [diff] [blame] | 49 | Note that objects created with PyObject_{New, NewVar} are allocated using the |
| 50 | specialized Python allocator (implemented in obmalloc.c), if WITH_PYMALLOC is |
| 51 | enabled. In addition, a special debugging allocator is used if PYMALLOC_DEBUG |
| 52 | is also #defined. |
Guido van Rossum | b18618d | 2000-05-03 23:44:39 +0000 | [diff] [blame] | 53 | |
Tim Peters | 8b078f9 | 2002-04-28 04:11:46 +0000 | [diff] [blame] | 54 | In case a specific form of memory management is needed (for example, if you |
| 55 | must use the platform malloc heap(s), or shared memory, or C++ local storage or |
| 56 | operator new), you must first allocate the object with your custom allocator, |
| 57 | then pass its pointer to PyObject_{Init, InitVar} for filling in its Python- |
| 58 | specific fields: reference count, type pointer, possibly others. You should |
Alexey | 517da1e | 2018-02-07 02:07:30 +0300 | [diff] [blame] | 59 | be aware that Python has no control over these objects because they don't |
Tim Peters | 8b078f9 | 2002-04-28 04:11:46 +0000 | [diff] [blame] | 60 | cooperate with the Python memory manager. Such objects may not be eligible |
| 61 | for automatic garbage collection and you have to make sure that they are |
| 62 | released accordingly whenever their destructor gets called (cf. the specific |
Guido van Rossum | b18618d | 2000-05-03 23:44:39 +0000 | [diff] [blame] | 63 | form of memory management you're using). |
| 64 | |
Tim Peters | 8b078f9 | 2002-04-28 04:11:46 +0000 | [diff] [blame] | 65 | Unless you have specific memory management requirements, use |
| 66 | PyObject_{New, NewVar, Del}. |
| 67 | */ |
Guido van Rossum | b18618d | 2000-05-03 23:44:39 +0000 | [diff] [blame] | 68 | |
Tim Peters | 6d483d3 | 2001-10-06 21:27:34 +0000 | [diff] [blame] | 69 | /* |
Guido van Rossum | b18618d | 2000-05-03 23:44:39 +0000 | [diff] [blame] | 70 | * Raw object memory interface |
| 71 | * =========================== |
| 72 | */ |
| 73 | |
Tim Peters | e9e7452 | 2002-04-12 05:21:34 +0000 | [diff] [blame] | 74 | /* Functions to call the same malloc/realloc/free as used by Python's |
| 75 | object allocator. If WITH_PYMALLOC is enabled, these may differ from |
| 76 | the platform malloc/realloc/free. The Python object allocator is |
| 77 | designed for fast, cache-conscious allocation of many "small" objects, |
Tim Peters | 8b078f9 | 2002-04-28 04:11:46 +0000 | [diff] [blame] | 78 | and with low hidden memory overhead. |
| 79 | |
| 80 | PyObject_Malloc(0) returns a unique non-NULL pointer if possible. |
| 81 | |
| 82 | PyObject_Realloc(NULL, n) acts like PyObject_Malloc(n). |
| 83 | PyObject_Realloc(p != NULL, 0) does not return NULL, or free the memory |
| 84 | at p. |
| 85 | |
| 86 | Returned pointers must be checked for NULL explicitly; no action is |
| 87 | performed on failure other than to return NULL (no warning it printed, no |
| 88 | exception is set, etc). |
| 89 | |
| 90 | For allocating objects, use PyObject_{New, NewVar} instead whenever |
| 91 | possible. The PyObject_{Malloc, Realloc, Free} family is exposed |
| 92 | so that you can exploit Python's small-block allocator for non-object |
| 93 | uses. If you must use these routines to allocate object memory, make sure |
| 94 | the object gets initialized via PyObject_{Init, InitVar} after obtaining |
| 95 | the raw memory. |
| 96 | */ |
Victor Stinner | 0507bf5 | 2013-07-07 02:05:46 +0200 | [diff] [blame] | 97 | PyAPI_FUNC(void *) PyObject_Malloc(size_t size); |
Serhiy Storchaka | 34d0ac8 | 2016-12-27 14:57:39 +0200 | [diff] [blame] | 98 | #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03050000 |
Victor Stinner | db067af | 2014-05-02 22:31:14 +0200 | [diff] [blame] | 99 | PyAPI_FUNC(void *) PyObject_Calloc(size_t nelem, size_t elsize); |
Serhiy Storchaka | 34d0ac8 | 2016-12-27 14:57:39 +0200 | [diff] [blame] | 100 | #endif |
Victor Stinner | 0507bf5 | 2013-07-07 02:05:46 +0200 | [diff] [blame] | 101 | PyAPI_FUNC(void *) PyObject_Realloc(void *ptr, size_t new_size); |
| 102 | PyAPI_FUNC(void) PyObject_Free(void *ptr); |
Guido van Rossum | b18618d | 2000-05-03 23:44:39 +0000 | [diff] [blame] | 103 | |
Neil Schemenauer | 3e7b893 | 2002-04-12 02:38:45 +0000 | [diff] [blame] | 104 | |
Victor Stinner | 0507bf5 | 2013-07-07 02:05:46 +0200 | [diff] [blame] | 105 | /* Macros */ |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 106 | #define PyObject_MALLOC PyObject_Malloc |
| 107 | #define PyObject_REALLOC PyObject_Realloc |
| 108 | #define PyObject_FREE PyObject_Free |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 109 | #define PyObject_Del PyObject_Free |
Victor Stinner | 0507bf5 | 2013-07-07 02:05:46 +0200 | [diff] [blame] | 110 | #define PyObject_DEL PyObject_Free |
| 111 | |
Neil Schemenauer | 3e7b893 | 2002-04-12 02:38:45 +0000 | [diff] [blame] | 112 | |
Guido van Rossum | b18618d | 2000-05-03 23:44:39 +0000 | [diff] [blame] | 113 | /* |
| 114 | * Generic object allocator interface |
| 115 | * ================================== |
| 116 | */ |
| 117 | |
| 118 | /* Functions */ |
Mark Hammond | 91a681d | 2002-08-12 07:21:58 +0000 | [diff] [blame] | 119 | PyAPI_FUNC(PyObject *) PyObject_Init(PyObject *, PyTypeObject *); |
| 120 | PyAPI_FUNC(PyVarObject *) PyObject_InitVar(PyVarObject *, |
Martin v. Löwis | 18e1655 | 2006-02-15 17:27:45 +0000 | [diff] [blame] | 121 | PyTypeObject *, Py_ssize_t); |
Mark Hammond | 91a681d | 2002-08-12 07:21:58 +0000 | [diff] [blame] | 122 | PyAPI_FUNC(PyObject *) _PyObject_New(PyTypeObject *); |
Martin v. Löwis | 18e1655 | 2006-02-15 17:27:45 +0000 | [diff] [blame] | 123 | PyAPI_FUNC(PyVarObject *) _PyObject_NewVar(PyTypeObject *, Py_ssize_t); |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 124 | |
Victor Stinner | 9205520 | 2020-04-08 00:38:15 +0200 | [diff] [blame] | 125 | #define PyObject_New(type, typeobj) ((type *)_PyObject_New(typeobj)) |
| 126 | |
| 127 | // Alias to PyObject_New(). In Python 3.8, PyObject_NEW() called directly |
| 128 | // PyObject_MALLOC() with _PyObject_SIZE(). |
| 129 | #define PyObject_NEW(type, typeobj) PyObject_New(type, typeobj) |
| 130 | |
Guido van Rossum | b18618d | 2000-05-03 23:44:39 +0000 | [diff] [blame] | 131 | #define PyObject_NewVar(type, typeobj, n) \ |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 132 | ( (type *) _PyObject_NewVar((typeobj), (n)) ) |
Guido van Rossum | a330996 | 1993-07-28 09:05:47 +0000 | [diff] [blame] | 133 | |
Victor Stinner | 9205520 | 2020-04-08 00:38:15 +0200 | [diff] [blame] | 134 | // Alias to PyObject_New(). In Python 3.8, PyObject_NEW() called directly |
| 135 | // PyObject_MALLOC() with _PyObject_VAR_SIZE(). |
| 136 | #define PyObject_NEW_VAR(type, typeobj, n) PyObject_NewVar(type, typeobj, n) |
Tim Peters | 6d483d3 | 2001-10-06 21:27:34 +0000 | [diff] [blame] | 137 | |
Victor Stinner | f58bd7c | 2020-02-05 13:12:19 +0100 | [diff] [blame] | 138 | |
| 139 | #ifdef Py_LIMITED_API |
| 140 | /* Define PyObject_INIT() and PyObject_INIT_VAR() as aliases to PyObject_Init() |
| 141 | and PyObject_InitVar() in the limited C API for compatibility with the |
| 142 | CPython C API. */ |
| 143 | # define PyObject_INIT(op, typeobj) \ |
| 144 | PyObject_Init(_PyObject_CAST(op), (typeobj)) |
| 145 | # define PyObject_INIT_VAR(op, typeobj, size) \ |
| 146 | PyObject_InitVar(_PyVarObject_CAST(op), (typeobj), (size)) |
| 147 | #else |
| 148 | /* PyObject_INIT() and PyObject_INIT_VAR() are defined in cpython/objimpl.h */ |
| 149 | #endif |
| 150 | |
| 151 | |
Jeremy Hylton | c5007aa | 2000-06-30 05:02:53 +0000 | [diff] [blame] | 152 | /* |
| 153 | * Garbage Collection Support |
| 154 | * ========================== |
| 155 | */ |
Jeremy Hylton | d08b4c4 | 2000-06-23 19:37:02 +0000 | [diff] [blame] | 156 | |
Łukasz Langa | fef7e94 | 2016-09-09 21:47:46 -0700 | [diff] [blame] | 157 | /* C equivalent of gc.collect() which ignores the state of gc.enabled. */ |
Neal Norwitz | 7b216c5 | 2006-03-04 20:01:53 +0000 | [diff] [blame] | 158 | PyAPI_FUNC(Py_ssize_t) PyGC_Collect(void); |
Guido van Rossum | e13ddc9 | 2003-04-17 17:29:22 +0000 | [diff] [blame] | 159 | |
Neil Schemenauer | 74b5ade | 2001-08-29 23:49:28 +0000 | [diff] [blame] | 160 | /* Test if a type has a GC head */ |
| 161 | #define PyType_IS_GC(t) PyType_HasFeature((t), Py_TPFLAGS_HAVE_GC) |
Jeremy Hylton | d08b4c4 | 2000-06-23 19:37:02 +0000 | [diff] [blame] | 162 | |
Martin v. Löwis | 4129068 | 2006-02-16 14:56:14 +0000 | [diff] [blame] | 163 | PyAPI_FUNC(PyVarObject *) _PyObject_GC_Resize(PyVarObject *, Py_ssize_t); |
Neil Schemenauer | 74b5ade | 2001-08-29 23:49:28 +0000 | [diff] [blame] | 164 | #define PyObject_GC_Resize(type, op, n) \ |
Victor Stinner | 2ff8fb7 | 2018-11-22 02:57:29 +0100 | [diff] [blame] | 165 | ( (type *) _PyObject_GC_Resize(_PyVarObject_CAST(op), (n)) ) |
Neil Schemenauer | 74b5ade | 2001-08-29 23:49:28 +0000 | [diff] [blame] | 166 | |
Victor Stinner | 1a6be91 | 2018-11-13 12:52:18 +0100 | [diff] [blame] | 167 | |
Victor Stinner | 1a6be91 | 2018-11-13 12:52:18 +0100 | [diff] [blame] | 168 | |
Mark Hammond | 91a681d | 2002-08-12 07:21:58 +0000 | [diff] [blame] | 169 | PyAPI_FUNC(PyObject *) _PyObject_GC_New(PyTypeObject *); |
Martin v. Löwis | 18e1655 | 2006-02-15 17:27:45 +0000 | [diff] [blame] | 170 | PyAPI_FUNC(PyVarObject *) _PyObject_GC_NewVar(PyTypeObject *, Py_ssize_t); |
Victor Stinner | 1a6be91 | 2018-11-13 12:52:18 +0100 | [diff] [blame] | 171 | |
| 172 | /* Tell the GC to track this object. |
| 173 | * |
| 174 | * See also private _PyObject_GC_TRACK() macro. */ |
Mark Hammond | 91a681d | 2002-08-12 07:21:58 +0000 | [diff] [blame] | 175 | PyAPI_FUNC(void) PyObject_GC_Track(void *); |
Victor Stinner | 1a6be91 | 2018-11-13 12:52:18 +0100 | [diff] [blame] | 176 | |
| 177 | /* Tell the GC to stop tracking this object. |
| 178 | * |
| 179 | * See also private _PyObject_GC_UNTRACK() macro. */ |
Mark Hammond | 91a681d | 2002-08-12 07:21:58 +0000 | [diff] [blame] | 180 | PyAPI_FUNC(void) PyObject_GC_UnTrack(void *); |
Victor Stinner | 1a6be91 | 2018-11-13 12:52:18 +0100 | [diff] [blame] | 181 | |
Mark Hammond | 91a681d | 2002-08-12 07:21:58 +0000 | [diff] [blame] | 182 | PyAPI_FUNC(void) PyObject_GC_Del(void *); |
Neil Schemenauer | 74b5ade | 2001-08-29 23:49:28 +0000 | [diff] [blame] | 183 | |
| 184 | #define PyObject_GC_New(type, typeobj) \ |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 185 | ( (type *) _PyObject_GC_New(typeobj) ) |
Neil Schemenauer | 74b5ade | 2001-08-29 23:49:28 +0000 | [diff] [blame] | 186 | #define PyObject_GC_NewVar(type, typeobj, n) \ |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 187 | ( (type *) _PyObject_GC_NewVar((typeobj), (n)) ) |
Neil Schemenauer | 3e7b893 | 2002-04-12 02:38:45 +0000 | [diff] [blame] | 188 | |
Pablo Galindo | f13072b | 2020-04-11 01:21:54 +0100 | [diff] [blame] | 189 | PyAPI_FUNC(int) PyObject_GC_IsTracked(PyObject *); |
| 190 | PyAPI_FUNC(int) PyObject_GC_IsFinalized(PyObject *); |
Neil Schemenauer | 74b5ade | 2001-08-29 23:49:28 +0000 | [diff] [blame] | 191 | |
Tim Peters | eda2930 | 2004-07-15 04:05:59 +0000 | [diff] [blame] | 192 | /* Utility macro to help write tp_traverse functions. |
| 193 | * To use this macro, the tp_traverse function must name its arguments |
| 194 | * "visit" and "arg". This is intended to keep tp_traverse functions |
| 195 | * looking as much alike as possible. |
| 196 | */ |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 197 | #define Py_VISIT(op) \ |
| 198 | do { \ |
| 199 | if (op) { \ |
Victor Stinner | 2ff8fb7 | 2018-11-22 02:57:29 +0100 | [diff] [blame] | 200 | int vret = visit(_PyObject_CAST(op), arg); \ |
Antoine Pitrou | f95a1b3 | 2010-05-09 15:52:27 +0000 | [diff] [blame] | 201 | if (vret) \ |
| 202 | return vret; \ |
| 203 | } \ |
| 204 | } while (0) |
Jim Fulton | aa6389e | 2004-07-14 19:08:17 +0000 | [diff] [blame] | 205 | |
Christian Tismer | ea62ce7 | 2018-06-09 20:32:25 +0200 | [diff] [blame] | 206 | #ifndef Py_LIMITED_API |
Victor Stinner | e421106 | 2018-11-23 17:00:00 +0100 | [diff] [blame] | 207 | # define Py_CPYTHON_OBJIMPL_H |
| 208 | # include "cpython/objimpl.h" |
| 209 | # undef Py_CPYTHON_OBJIMPL_H |
Christian Tismer | ea62ce7 | 2018-06-09 20:32:25 +0200 | [diff] [blame] | 210 | #endif |
Fred Drake | 41deb1e | 2001-02-01 05:27:45 +0000 | [diff] [blame] | 211 | |
Guido van Rossum | a330996 | 1993-07-28 09:05:47 +0000 | [diff] [blame] | 212 | #ifdef __cplusplus |
| 213 | } |
| 214 | #endif |
| 215 | #endif /* !Py_OBJIMPL_H */ |