1/* The PyObject_ memory family: high-level object memory interfaces. 2 See pymem.h for the low-level PyMem_ family. 3*/ 4 5#ifndef Py_OBJIMPL_H 6#define Py_OBJIMPL_H 7 8#include "pymem.h" 9 10#ifdef __cplusplus 11extern "C" { 12#endif 13 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 26/* 27Functions and macros for modules that implement new object types. 28 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. 36 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. 40 41 - PyObject_Free(op) releases the memory allocated for an object. It does not 42 run a destructor -- it only frees the memory. PyObject_Free is identical. 43 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. 48 49Note that objects created with PyObject_{New, NewVar} are allocated using the 50specialized Python allocator (implemented in obmalloc.c), if WITH_PYMALLOC is 51enabled. In addition, a special debugging allocator is used if Py_DEBUG 52macro is also defined. 53 54In case a specific form of memory management is needed (for example, if you 55must use the platform malloc heap(s), or shared memory, or C++ local storage or 56operator new), you must first allocate the object with your custom allocator, 57then pass its pointer to PyObject_{Init, InitVar} for filling in its Python- 58specific fields: reference count, type pointer, possibly others. You should 59be aware that Python has no control over these objects because they don't 60cooperate with the Python memory manager. Such objects may not be eligible 61for automatic garbage collection and you have to make sure that they are 62released accordingly whenever their destructor gets called (cf. the specific 63form of memory management you're using). 64 65Unless you have specific memory management requirements, use 66PyObject_{New, NewVar, Del}. 67*/ 68 69/* 70 * Raw object memory interface 71 * =========================== 72 */ 73 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, 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*/ 97PyAPI_FUNC(void *) PyObject_Malloc(size_t size); 98#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03050000 99PyAPI_FUNC(void *) PyObject_Calloc(size_t nelem, size_t elsize); 100#endif 101PyAPI_FUNC(void *) PyObject_Realloc(void *ptr, size_t new_size); 102PyAPI_FUNC(void) PyObject_Free(void *ptr); 103 104 105// Deprecated aliases only kept for backward compatibility. 106// PyObject_Del and PyObject_DEL are defined with no parameter to be able to 107// use them as function pointers (ex: tp_free = PyObject_Del). 108#define PyObject_MALLOC PyObject_Malloc 109#define PyObject_REALLOC PyObject_Realloc 110#define PyObject_FREE PyObject_Free 111#define PyObject_Del PyObject_Free 112#define PyObject_DEL PyObject_Free 113 114 115/* 116 * Generic object allocator interface 117 * ================================== 118 */ 119 120/* Functions */ 121PyAPI_FUNC(PyObject *) PyObject_Init(PyObject *, PyTypeObject *); 122PyAPI_FUNC(PyVarObject *) PyObject_InitVar(PyVarObject *, 123 PyTypeObject *, Py_ssize_t); 124 125#define PyObject_INIT(op, typeobj) \ 126 PyObject_Init(_PyObject_CAST(op), (typeobj)) 127#define PyObject_INIT_VAR(op, typeobj, size) \ 128 PyObject_InitVar(_PyVarObject_CAST(op), (typeobj), (size)) 129 130 131PyAPI_FUNC(PyObject *) _PyObject_New(PyTypeObject *); 132PyAPI_FUNC(PyVarObject *) _PyObject_NewVar(PyTypeObject *, Py_ssize_t); 133 134#define PyObject_New(type, typeobj) ((type *)_PyObject_New(typeobj)) 135 136// Alias to PyObject_New(). In Python 3.8, PyObject_NEW() called directly 137// PyObject_MALLOC() with _PyObject_SIZE(). 138#define PyObject_NEW(type, typeobj) PyObject_New(type, typeobj) 139 140#define PyObject_NewVar(type, typeobj, n) \ 141 ( (type *) _PyObject_NewVar((typeobj), (n)) ) 142 143// Alias to PyObject_NewVar(). In Python 3.8, PyObject_NEW_VAR() called 144// directly PyObject_MALLOC() with _PyObject_VAR_SIZE(). 145#define PyObject_NEW_VAR(type, typeobj, n) PyObject_NewVar(type, typeobj, n) 146 147 148/* 149 * Garbage Collection Support 150 * ========================== 151 */ 152 153/* C equivalent of gc.collect(). */ 154PyAPI_FUNC(Py_ssize_t) PyGC_Collect(void); 155/* C API for controlling the state of the garbage collector */ 156PyAPI_FUNC(int) PyGC_Enable(void); 157PyAPI_FUNC(int) PyGC_Disable(void); 158PyAPI_FUNC(int) PyGC_IsEnabled(void); 159 160/* Test if a type has a GC head */ 161#define PyType_IS_GC(t) PyType_HasFeature((t), Py_TPFLAGS_HAVE_GC) 162 163PyAPI_FUNC(PyVarObject *) _PyObject_GC_Resize(PyVarObject *, Py_ssize_t); 164#define PyObject_GC_Resize(type, op, n) \ 165 ( (type *) _PyObject_GC_Resize(_PyVarObject_CAST(op), (n)) ) 166 167 168 169PyAPI_FUNC(PyObject *) _PyObject_GC_New(PyTypeObject *); 170PyAPI_FUNC(PyVarObject *) _PyObject_GC_NewVar(PyTypeObject *, Py_ssize_t); 171 172/* Tell the GC to track this object. 173 * 174 * See also private _PyObject_GC_TRACK() macro. */ 175PyAPI_FUNC(void) PyObject_GC_Track(void *); 176 177/* Tell the GC to stop tracking this object. 178 * 179 * See also private _PyObject_GC_UNTRACK() macro. */ 180PyAPI_FUNC(void) PyObject_GC_UnTrack(void *); 181 182PyAPI_FUNC(void) PyObject_GC_Del(void *); 183 184#define PyObject_GC_New(type, typeobj) \ 185 _Py_CAST(type*, _PyObject_GC_New(typeobj)) 186#define PyObject_GC_NewVar(type, typeobj, n) \ 187 _Py_CAST(type*, _PyObject_GC_NewVar((typeobj), (n))) 188 189PyAPI_FUNC(int) PyObject_GC_IsTracked(PyObject *); 190PyAPI_FUNC(int) PyObject_GC_IsFinalized(PyObject *); 191 192/* 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 */ 197#define Py_VISIT(op) \ 198 do { \ 199 if (op) { \ 200 int vret = visit(_PyObject_CAST(op), arg); \ 201 if (vret) \ 202 return vret; \ 203 } \ 204 } while (0) 205 206#ifndef Py_LIMITED_API 207# define Py_CPYTHON_OBJIMPL_H 208# include "cpython/objimpl.h" 209# undef Py_CPYTHON_OBJIMPL_H 210#endif 211 212#ifdef __cplusplus 213} 214#endif 215#endif /* !Py_OBJIMPL_H */ 216