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Diffstat (limited to 'include/python2.7/objimpl.h')
| -rw-r--r-- | include/python2.7/objimpl.h | 360 |
1 files changed, 360 insertions, 0 deletions
diff --git a/include/python2.7/objimpl.h b/include/python2.7/objimpl.h new file mode 100644 index 0000000..66a9607 --- /dev/null +++ b/include/python2.7/objimpl.h @@ -0,0 +1,360 @@ +/* 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 */ +#if defined(__MINGW32__) +/* FIXME: what about 64-bit platforms ? + * see http://mail.python.org/pipermail/python-dev/2009-July/090724.html + */ + double dummy1; +#endif +} 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 */ |