123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354 |
- /* The PyObject_ memory family: high-level object memory interfaces.
- See pymem.h for the low-level PyMem_ family.
- */
- #ifndef Py_OBJIMPL_H
- #define Py_OBJIMPL_H
- #include "pymem.h"
- #ifdef __cplusplus
- extern "C" {
- #endif
- /* BEWARE:
- Each interface exports both functions and macros. Extension modules should
- use the functions, to ensure binary compatibility across Python versions.
- Because the Python implementation is free to change internal details, and
- the macros may (or may not) expose details for speed, if you do use the
- macros you must recompile your extensions with each Python release.
- Never mix calls to PyObject_ memory functions with calls to the platform
- malloc/realloc/ calloc/free, or with calls to PyMem_.
- */
- /*
- Functions and macros for modules that implement new object types.
- - PyObject_New(type, typeobj) allocates memory for a new object of the given
- type, and initializes part of it. 'type' must be the C structure type used
- to represent the object, and 'typeobj' the address of the corresponding
- type object. Reference count and type pointer are filled in; the rest of
- the bytes of the object are *undefined*! The resulting expression type is
- 'type *'. The size of the object is determined by the tp_basicsize field
- of the type object.
- - PyObject_NewVar(type, typeobj, n) is similar but allocates a variable-size
- object with room for n items. In addition to the refcount and type pointer
- fields, this also fills in the ob_size field.
- - PyObject_Del(op) releases the memory allocated for an object. It does not
- run a destructor -- it only frees the memory. PyObject_Free is identical.
- - PyObject_Init(op, typeobj) and PyObject_InitVar(op, typeobj, n) don't
- allocate memory. Instead of a 'type' parameter, they take a pointer to a
- new object (allocated by an arbitrary allocator), and initialize its object
- header fields.
- Note that objects created with PyObject_{New, NewVar} are allocated using the
- specialized Python allocator (implemented in obmalloc.c), if WITH_PYMALLOC is
- enabled. In addition, a special debugging allocator is used if PYMALLOC_DEBUG
- is also #defined.
- In case a specific form of memory management is needed (for example, if you
- must use the platform malloc heap(s), or shared memory, or C++ local storage or
- operator new), you must first allocate the object with your custom allocator,
- then pass its pointer to PyObject_{Init, InitVar} for filling in its Python-
- specific fields: reference count, type pointer, possibly others. You should
- be aware that Python no control over these objects because they don't
- cooperate with the Python memory manager. Such objects may not be eligible
- for automatic garbage collection and you have to make sure that they are
- released accordingly whenever their destructor gets called (cf. the specific
- form of memory management you're using).
- Unless you have specific memory management requirements, use
- PyObject_{New, NewVar, Del}.
- */
- /*
- * Raw object memory interface
- * ===========================
- */
- /* Functions to call the same malloc/realloc/free as used by Python's
- object allocator. If WITH_PYMALLOC is enabled, these may differ from
- the platform malloc/realloc/free. The Python object allocator is
- designed for fast, cache-conscious allocation of many "small" objects,
- and with low hidden memory overhead.
- PyObject_Malloc(0) returns a unique non-NULL pointer if possible.
- PyObject_Realloc(NULL, n) acts like PyObject_Malloc(n).
- PyObject_Realloc(p != NULL, 0) does not return NULL, or free the memory
- at p.
- Returned pointers must be checked for NULL explicitly; no action is
- performed on failure other than to return NULL (no warning it printed, no
- exception is set, etc).
- For allocating objects, use PyObject_{New, NewVar} instead whenever
- possible. The PyObject_{Malloc, Realloc, Free} family is exposed
- so that you can exploit Python's small-block allocator for non-object
- uses. If you must use these routines to allocate object memory, make sure
- the object gets initialized via PyObject_{Init, InitVar} after obtaining
- the raw memory.
- */
- PyAPI_FUNC(void *) PyObject_Malloc(size_t);
- PyAPI_FUNC(void *) PyObject_Realloc(void *, size_t);
- PyAPI_FUNC(void) PyObject_Free(void *);
- /* Macros */
- #ifdef WITH_PYMALLOC
- #ifdef PYMALLOC_DEBUG /* WITH_PYMALLOC && PYMALLOC_DEBUG */
- PyAPI_FUNC(void *) _PyObject_DebugMalloc(size_t nbytes);
- PyAPI_FUNC(void *) _PyObject_DebugRealloc(void *p, size_t nbytes);
- PyAPI_FUNC(void) _PyObject_DebugFree(void *p);
- PyAPI_FUNC(void) _PyObject_DebugDumpAddress(const void *p);
- PyAPI_FUNC(void) _PyObject_DebugCheckAddress(const void *p);
- PyAPI_FUNC(void) _PyObject_DebugMallocStats(void);
- PyAPI_FUNC(void *) _PyObject_DebugMallocApi(char api, size_t nbytes);
- PyAPI_FUNC(void *) _PyObject_DebugReallocApi(char api, void *p, size_t nbytes);
- PyAPI_FUNC(void) _PyObject_DebugFreeApi(char api, void *p);
- PyAPI_FUNC(void) _PyObject_DebugCheckAddressApi(char api, const void *p);
- PyAPI_FUNC(void *) _PyMem_DebugMalloc(size_t nbytes);
- PyAPI_FUNC(void *) _PyMem_DebugRealloc(void *p, size_t nbytes);
- PyAPI_FUNC(void) _PyMem_DebugFree(void *p);
- #define PyObject_MALLOC _PyObject_DebugMalloc
- #define PyObject_Malloc _PyObject_DebugMalloc
- #define PyObject_REALLOC _PyObject_DebugRealloc
- #define PyObject_Realloc _PyObject_DebugRealloc
- #define PyObject_FREE _PyObject_DebugFree
- #define PyObject_Free _PyObject_DebugFree
- #else /* WITH_PYMALLOC && ! PYMALLOC_DEBUG */
- #define PyObject_MALLOC PyObject_Malloc
- #define PyObject_REALLOC PyObject_Realloc
- #define PyObject_FREE PyObject_Free
- #endif
- #else /* ! WITH_PYMALLOC */
- #define PyObject_MALLOC PyMem_MALLOC
- #define PyObject_REALLOC PyMem_REALLOC
- #define PyObject_FREE PyMem_FREE
- #endif /* WITH_PYMALLOC */
- #define PyObject_Del PyObject_Free
- #define PyObject_DEL PyObject_FREE
- /* for source compatibility with 2.2 */
- #define _PyObject_Del PyObject_Free
- /*
- * Generic object allocator interface
- * ==================================
- */
- /* Functions */
- PyAPI_FUNC(PyObject *) PyObject_Init(PyObject *, PyTypeObject *);
- PyAPI_FUNC(PyVarObject *) PyObject_InitVar(PyVarObject *,
- PyTypeObject *, Py_ssize_t);
- PyAPI_FUNC(PyObject *) _PyObject_New(PyTypeObject *);
- PyAPI_FUNC(PyVarObject *) _PyObject_NewVar(PyTypeObject *, Py_ssize_t);
- #define PyObject_New(type, typeobj) \
- ( (type *) _PyObject_New(typeobj) )
- #define PyObject_NewVar(type, typeobj, n) \
- ( (type *) _PyObject_NewVar((typeobj), (n)) )
- /* Macros trading binary compatibility for speed. See also pymem.h.
- Note that these macros expect non-NULL object pointers.*/
- #define PyObject_INIT(op, typeobj) \
- ( Py_TYPE(op) = (typeobj), _Py_NewReference((PyObject *)(op)), (op) )
- #define PyObject_INIT_VAR(op, typeobj, size) \
- ( Py_SIZE(op) = (size), PyObject_INIT((op), (typeobj)) )
- #define _PyObject_SIZE(typeobj) ( (typeobj)->tp_basicsize )
- /* _PyObject_VAR_SIZE returns the number of bytes (as size_t) allocated for a
- vrbl-size object with nitems items, exclusive of gc overhead (if any). The
- value is rounded up to the closest multiple of sizeof(void *), in order to
- ensure that pointer fields at the end of the object are correctly aligned
- for the platform (this is of special importance for subclasses of, e.g.,
- str or long, so that pointers can be stored after the embedded data).
- Note that there's no memory wastage in doing this, as malloc has to
- return (at worst) pointer-aligned memory anyway.
- */
- #if ((SIZEOF_VOID_P - 1) & SIZEOF_VOID_P) != 0
- # error "_PyObject_VAR_SIZE requires SIZEOF_VOID_P be a power of 2"
- #endif
- #define _PyObject_VAR_SIZE(typeobj, nitems) \
- (size_t) \
- ( ( (typeobj)->tp_basicsize + \
- (nitems)*(typeobj)->tp_itemsize + \
- (SIZEOF_VOID_P - 1) \
- ) & ~(SIZEOF_VOID_P - 1) \
- )
- #define PyObject_NEW(type, typeobj) \
- ( (type *) PyObject_Init( \
- (PyObject *) PyObject_MALLOC( _PyObject_SIZE(typeobj) ), (typeobj)) )
- #define PyObject_NEW_VAR(type, typeobj, n) \
- ( (type *) PyObject_InitVar( \
- (PyVarObject *) PyObject_MALLOC(_PyObject_VAR_SIZE((typeobj),(n)) ),\
- (typeobj), (n)) )
- /* This example code implements an object constructor with a custom
- allocator, where PyObject_New is inlined, and shows the important
- distinction between two steps (at least):
- 1) the actual allocation of the object storage;
- 2) the initialization of the Python specific fields
- in this storage with PyObject_{Init, InitVar}.
- PyObject *
- YourObject_New(...)
- {
- PyObject *op;
- op = (PyObject *) Your_Allocator(_PyObject_SIZE(YourTypeStruct));
- if (op == NULL)
- return PyErr_NoMemory();
- PyObject_Init(op, &YourTypeStruct);
- op->ob_field = value;
- ...
- return op;
- }
- Note that in C++, the use of the new operator usually implies that
- the 1st step is performed automatically for you, so in a C++ class
- constructor you would start directly with PyObject_Init/InitVar
- */
- /*
- * Garbage Collection Support
- * ==========================
- */
- /* C equivalent of gc.collect(). */
- PyAPI_FUNC(Py_ssize_t) PyGC_Collect(void);
- /* Test if a type has a GC head */
- #define PyType_IS_GC(t) PyType_HasFeature((t), Py_TPFLAGS_HAVE_GC)
- /* Test if an object has a GC head */
- #define PyObject_IS_GC(o) (PyType_IS_GC(Py_TYPE(o)) && \
- (Py_TYPE(o)->tp_is_gc == NULL || Py_TYPE(o)->tp_is_gc(o)))
- PyAPI_FUNC(PyVarObject *) _PyObject_GC_Resize(PyVarObject *, Py_ssize_t);
- #define PyObject_GC_Resize(type, op, n) \
- ( (type *) _PyObject_GC_Resize((PyVarObject *)(op), (n)) )
- /* for source compatibility with 2.2 */
- #define _PyObject_GC_Del PyObject_GC_Del
- /* GC information is stored BEFORE the object structure. */
- typedef union _gc_head {
- struct {
- union _gc_head *gc_next;
- union _gc_head *gc_prev;
- Py_ssize_t gc_refs;
- } gc;
- long double dummy; /* force worst-case alignment */
- } PyGC_Head;
- extern PyGC_Head *_PyGC_generation0;
- #define _Py_AS_GC(o) ((PyGC_Head *)(o)-1)
- #define _PyGC_REFS_UNTRACKED (-2)
- #define _PyGC_REFS_REACHABLE (-3)
- #define _PyGC_REFS_TENTATIVELY_UNREACHABLE (-4)
- /* Tell the GC to track this object. NB: While the object is tracked the
- * collector it must be safe to call the ob_traverse method. */
- #define _PyObject_GC_TRACK(o) do { \
- PyGC_Head *g = _Py_AS_GC(o); \
- if (g->gc.gc_refs != _PyGC_REFS_UNTRACKED) \
- Py_FatalError("GC object already tracked"); \
- g->gc.gc_refs = _PyGC_REFS_REACHABLE; \
- g->gc.gc_next = _PyGC_generation0; \
- g->gc.gc_prev = _PyGC_generation0->gc.gc_prev; \
- g->gc.gc_prev->gc.gc_next = g; \
- _PyGC_generation0->gc.gc_prev = g; \
- } while (0);
- /* Tell the GC to stop tracking this object.
- * gc_next doesn't need to be set to NULL, but doing so is a good
- * way to provoke memory errors if calling code is confused.
- */
- #define _PyObject_GC_UNTRACK(o) do { \
- PyGC_Head *g = _Py_AS_GC(o); \
- assert(g->gc.gc_refs != _PyGC_REFS_UNTRACKED); \
- g->gc.gc_refs = _PyGC_REFS_UNTRACKED; \
- g->gc.gc_prev->gc.gc_next = g->gc.gc_next; \
- g->gc.gc_next->gc.gc_prev = g->gc.gc_prev; \
- g->gc.gc_next = NULL; \
- } while (0);
- /* True if the object is currently tracked by the GC. */
- #define _PyObject_GC_IS_TRACKED(o) \
- ((_Py_AS_GC(o))->gc.gc_refs != _PyGC_REFS_UNTRACKED)
- /* True if the object may be tracked by the GC in the future, or already is.
- This can be useful to implement some optimizations. */
- #define _PyObject_GC_MAY_BE_TRACKED(obj) \
- (PyObject_IS_GC(obj) && \
- (!PyTuple_CheckExact(obj) || _PyObject_GC_IS_TRACKED(obj)))
- PyAPI_FUNC(PyObject *) _PyObject_GC_Malloc(size_t);
- PyAPI_FUNC(PyObject *) _PyObject_GC_New(PyTypeObject *);
- PyAPI_FUNC(PyVarObject *) _PyObject_GC_NewVar(PyTypeObject *, Py_ssize_t);
- PyAPI_FUNC(void) PyObject_GC_Track(void *);
- PyAPI_FUNC(void) PyObject_GC_UnTrack(void *);
- PyAPI_FUNC(void) PyObject_GC_Del(void *);
- #define PyObject_GC_New(type, typeobj) \
- ( (type *) _PyObject_GC_New(typeobj) )
- #define PyObject_GC_NewVar(type, typeobj, n) \
- ( (type *) _PyObject_GC_NewVar((typeobj), (n)) )
- /* Utility macro to help write tp_traverse functions.
- * To use this macro, the tp_traverse function must name its arguments
- * "visit" and "arg". This is intended to keep tp_traverse functions
- * looking as much alike as possible.
- */
- #define Py_VISIT(op) \
- do { \
- if (op) { \
- int vret = visit((PyObject *)(op), arg); \
- if (vret) \
- return vret; \
- } \
- } while (0)
- /* This is here for the sake of backwards compatibility. Extensions that
- * use the old GC API will still compile but the objects will not be
- * tracked by the GC. */
- #define PyGC_HEAD_SIZE 0
- #define PyObject_GC_Init(op)
- #define PyObject_GC_Fini(op)
- #define PyObject_AS_GC(op) (op)
- #define PyObject_FROM_GC(op) (op)
- /* Test if a type supports weak references */
- #define PyType_SUPPORTS_WEAKREFS(t) \
- (PyType_HasFeature((t), Py_TPFLAGS_HAVE_WEAKREFS) \
- && ((t)->tp_weaklistoffset > 0))
- #define PyObject_GET_WEAKREFS_LISTPTR(o) \
- ((PyObject **) (((char *) (o)) + Py_TYPE(o)->tp_weaklistoffset))
- #ifdef __cplusplus
- }
- #endif
- #endif /* !Py_OBJIMPL_H */
|