mirror of https://github.com/python/cpython.git
590 lines
20 KiB
C
590 lines
20 KiB
C
#ifndef Py_OBJECT_H
|
|
#define Py_OBJECT_H
|
|
#ifdef __cplusplus
|
|
extern "C" {
|
|
#endif
|
|
|
|
/***********************************************************
|
|
Copyright 1991-1995 by Stichting Mathematisch Centrum, Amsterdam,
|
|
The Netherlands.
|
|
|
|
All Rights Reserved
|
|
|
|
Permission to use, copy, modify, and distribute this software and its
|
|
documentation for any purpose and without fee is hereby granted,
|
|
provided that the above copyright notice appear in all copies and that
|
|
both that copyright notice and this permission notice appear in
|
|
supporting documentation, and that the names of Stichting Mathematisch
|
|
Centrum or CWI or Corporation for National Research Initiatives or
|
|
CNRI not be used in advertising or publicity pertaining to
|
|
distribution of the software without specific, written prior
|
|
permission.
|
|
|
|
While CWI is the initial source for this software, a modified version
|
|
is made available by the Corporation for National Research Initiatives
|
|
(CNRI) at the Internet address ftp://ftp.python.org.
|
|
|
|
STICHTING MATHEMATISCH CENTRUM AND CNRI DISCLAIM ALL WARRANTIES WITH
|
|
REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF
|
|
MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH
|
|
CENTRUM OR CNRI BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL
|
|
DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
|
|
PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
|
|
TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
|
|
PERFORMANCE OF THIS SOFTWARE.
|
|
|
|
******************************************************************/
|
|
|
|
/* Object and type object interface */
|
|
|
|
/*
|
|
Objects are structures allocated on the heap. Special rules apply to
|
|
the use of objects to ensure they are properly garbage-collected.
|
|
Objects are never allocated statically or on the stack; they must be
|
|
accessed through special macros and functions only. (Type objects are
|
|
exceptions to the first rule; the standard types are represented by
|
|
statically initialized type objects.)
|
|
|
|
An object has a 'reference count' that is increased or decreased when a
|
|
pointer to the object is copied or deleted; when the reference count
|
|
reaches zero there are no references to the object left and it can be
|
|
removed from the heap.
|
|
|
|
An object has a 'type' that determines what it represents and what kind
|
|
of data it contains. An object's type is fixed when it is created.
|
|
Types themselves are represented as objects; an object contains a
|
|
pointer to the corresponding type object. The type itself has a type
|
|
pointer pointing to the object representing the type 'type', which
|
|
contains a pointer to itself!).
|
|
|
|
Objects do not float around in memory; once allocated an object keeps
|
|
the same size and address. Objects that must hold variable-size data
|
|
can contain pointers to variable-size parts of the object. Not all
|
|
objects of the same type have the same size; but the size cannot change
|
|
after allocation. (These restrictions are made so a reference to an
|
|
object can be simply a pointer -- moving an object would require
|
|
updating all the pointers, and changing an object's size would require
|
|
moving it if there was another object right next to it.)
|
|
|
|
Objects are always accessed through pointers of the type 'PyObject *'.
|
|
The type 'PyObject' is a structure that only contains the reference count
|
|
and the type pointer. The actual memory allocated for an object
|
|
contains other data that can only be accessed after casting the pointer
|
|
to a pointer to a longer structure type. This longer type must start
|
|
with the reference count and type fields; the macro PyObject_HEAD should be
|
|
used for this (to accomodate for future changes). The implementation
|
|
of a particular object type can cast the object pointer to the proper
|
|
type and back.
|
|
|
|
A standard interface exists for objects that contain an array of items
|
|
whose size is determined when the object is allocated.
|
|
*/
|
|
|
|
#ifdef Py_DEBUG
|
|
|
|
/* Turn on heavy reference debugging */
|
|
#define Py_TRACE_REFS
|
|
|
|
/* Turn on reference counting */
|
|
#define Py_REF_DEBUG
|
|
|
|
#endif /* Py_DEBUG */
|
|
|
|
#ifdef Py_TRACE_REFS
|
|
#define PyObject_HEAD \
|
|
struct _object *_ob_next, *_ob_prev; \
|
|
int ob_refcnt; \
|
|
struct _typeobject *ob_type;
|
|
#define PyObject_HEAD_INIT(type) 0, 0, 1, type,
|
|
#else /* !Py_TRACE_REFS */
|
|
#define PyObject_HEAD \
|
|
int ob_refcnt; \
|
|
struct _typeobject *ob_type;
|
|
#define PyObject_HEAD_INIT(type) 1, type,
|
|
#endif /* !Py_TRACE_REFS */
|
|
|
|
#define PyObject_VAR_HEAD \
|
|
PyObject_HEAD \
|
|
int ob_size; /* Number of items in variable part */
|
|
|
|
typedef struct _object {
|
|
PyObject_HEAD
|
|
} PyObject;
|
|
|
|
typedef struct {
|
|
PyObject_VAR_HEAD
|
|
} PyVarObject;
|
|
|
|
|
|
/*
|
|
Type objects contain a string containing the type name (to help somewhat
|
|
in debugging), the allocation parameters (see newobj() and newvarobj()),
|
|
and methods for accessing objects of the type. Methods are optional,a
|
|
nil pointer meaning that particular kind of access is not available for
|
|
this type. The Py_DECREF() macro uses the tp_dealloc method without
|
|
checking for a nil pointer; it should always be implemented except if
|
|
the implementation can guarantee that the reference count will never
|
|
reach zero (e.g., for type objects).
|
|
|
|
NB: the methods for certain type groups are now contained in separate
|
|
method blocks.
|
|
*/
|
|
|
|
typedef PyObject * (*unaryfunc) Py_PROTO((PyObject *));
|
|
typedef PyObject * (*binaryfunc) Py_PROTO((PyObject *, PyObject *));
|
|
typedef PyObject * (*ternaryfunc) Py_PROTO((PyObject *, PyObject *, PyObject *));
|
|
typedef int (*inquiry) Py_PROTO((PyObject *));
|
|
typedef int (*coercion) Py_PROTO((PyObject **, PyObject **));
|
|
typedef PyObject *(*intargfunc) Py_PROTO((PyObject *, int));
|
|
typedef PyObject *(*intintargfunc) Py_PROTO((PyObject *, int, int));
|
|
typedef int(*intobjargproc) Py_PROTO((PyObject *, int, PyObject *));
|
|
typedef int(*intintobjargproc) Py_PROTO((PyObject *, int, int, PyObject *));
|
|
typedef int(*objobjargproc) Py_PROTO((PyObject *, PyObject *, PyObject *));
|
|
typedef int (*getreadbufferproc) Py_PROTO((PyObject *, int, void **));
|
|
typedef int (*getwritebufferproc) Py_PROTO((PyObject *, int, void **));
|
|
typedef int (*getsegcountproc) Py_PROTO((PyObject *, int *));
|
|
typedef int (*getcharbufferproc) Py_PROTO((PyObject *, int, const char **));
|
|
typedef int (*objobjproc) Py_PROTO((PyObject *, PyObject *));
|
|
typedef int (*visitproc) Py_PROTO((PyObject *, void *));
|
|
typedef int (*traverseproc) Py_PROTO((PyObject *, visitproc, void *));
|
|
|
|
typedef struct {
|
|
binaryfunc nb_add;
|
|
binaryfunc nb_subtract;
|
|
binaryfunc nb_multiply;
|
|
binaryfunc nb_divide;
|
|
binaryfunc nb_remainder;
|
|
binaryfunc nb_divmod;
|
|
ternaryfunc nb_power;
|
|
unaryfunc nb_negative;
|
|
unaryfunc nb_positive;
|
|
unaryfunc nb_absolute;
|
|
inquiry nb_nonzero;
|
|
unaryfunc nb_invert;
|
|
binaryfunc nb_lshift;
|
|
binaryfunc nb_rshift;
|
|
binaryfunc nb_and;
|
|
binaryfunc nb_xor;
|
|
binaryfunc nb_or;
|
|
coercion nb_coerce;
|
|
unaryfunc nb_int;
|
|
unaryfunc nb_long;
|
|
unaryfunc nb_float;
|
|
unaryfunc nb_oct;
|
|
unaryfunc nb_hex;
|
|
} PyNumberMethods;
|
|
|
|
typedef struct {
|
|
inquiry sq_length;
|
|
binaryfunc sq_concat;
|
|
intargfunc sq_repeat;
|
|
intargfunc sq_item;
|
|
intintargfunc sq_slice;
|
|
intobjargproc sq_ass_item;
|
|
intintobjargproc sq_ass_slice;
|
|
objobjproc sq_contains;
|
|
} PySequenceMethods;
|
|
|
|
typedef struct {
|
|
inquiry mp_length;
|
|
binaryfunc mp_subscript;
|
|
objobjargproc mp_ass_subscript;
|
|
} PyMappingMethods;
|
|
|
|
typedef struct {
|
|
getreadbufferproc bf_getreadbuffer;
|
|
getwritebufferproc bf_getwritebuffer;
|
|
getsegcountproc bf_getsegcount;
|
|
getcharbufferproc bf_getcharbuffer;
|
|
} PyBufferProcs;
|
|
|
|
|
|
typedef void (*destructor) Py_PROTO((PyObject *));
|
|
typedef int (*printfunc) Py_PROTO((PyObject *, FILE *, int));
|
|
typedef PyObject *(*getattrfunc) Py_PROTO((PyObject *, char *));
|
|
typedef PyObject *(*getattrofunc) Py_PROTO((PyObject *, PyObject *));
|
|
typedef int (*setattrfunc) Py_PROTO((PyObject *, char *, PyObject *));
|
|
typedef int (*setattrofunc) Py_PROTO((PyObject *, PyObject *, PyObject *));
|
|
typedef int (*cmpfunc) Py_PROTO((PyObject *, PyObject *));
|
|
typedef PyObject *(*reprfunc) Py_PROTO((PyObject *));
|
|
typedef long (*hashfunc) Py_PROTO((PyObject *));
|
|
|
|
typedef struct _typeobject {
|
|
PyObject_VAR_HEAD
|
|
char *tp_name; /* For printing */
|
|
int tp_basicsize, tp_itemsize; /* For allocation */
|
|
|
|
/* Methods to implement standard operations */
|
|
|
|
destructor tp_dealloc;
|
|
printfunc tp_print;
|
|
getattrfunc tp_getattr;
|
|
setattrfunc tp_setattr;
|
|
cmpfunc tp_compare;
|
|
reprfunc tp_repr;
|
|
|
|
/* Method suites for standard classes */
|
|
|
|
PyNumberMethods *tp_as_number;
|
|
PySequenceMethods *tp_as_sequence;
|
|
PyMappingMethods *tp_as_mapping;
|
|
|
|
/* More standard operations (here for binary compatibility) */
|
|
|
|
hashfunc tp_hash;
|
|
ternaryfunc tp_call;
|
|
reprfunc tp_str;
|
|
getattrofunc tp_getattro;
|
|
setattrofunc tp_setattro;
|
|
|
|
/* Functions to access object as input/output buffer */
|
|
PyBufferProcs *tp_as_buffer;
|
|
|
|
/* Flags to define presence of optional/expanded features */
|
|
long tp_flags;
|
|
|
|
char *tp_doc; /* Documentation string */
|
|
|
|
/* call function for all accessible objects */
|
|
traverseproc tp_traverse;
|
|
|
|
/* delete references to contained objects */
|
|
inquiry tp_clear;
|
|
|
|
/* More spares */
|
|
long tp_xxx7;
|
|
long tp_xxx8;
|
|
|
|
#ifdef COUNT_ALLOCS
|
|
/* these must be last */
|
|
int tp_alloc;
|
|
int tp_free;
|
|
int tp_maxalloc;
|
|
struct _typeobject *tp_next;
|
|
#endif
|
|
} PyTypeObject;
|
|
|
|
extern DL_IMPORT(PyTypeObject) PyType_Type; /* The type of type objects */
|
|
|
|
#define PyType_Check(op) ((op)->ob_type == &PyType_Type)
|
|
|
|
/* Generic operations on objects */
|
|
extern DL_IMPORT(int) PyObject_Print Py_PROTO((PyObject *, FILE *, int));
|
|
extern DL_IMPORT(PyObject *) PyObject_Repr Py_PROTO((PyObject *));
|
|
extern DL_IMPORT(PyObject *) PyObject_Str Py_PROTO((PyObject *));
|
|
extern DL_IMPORT(int) PyObject_Compare Py_PROTO((PyObject *, PyObject *));
|
|
extern DL_IMPORT(PyObject *) PyObject_GetAttrString Py_PROTO((PyObject *, char *));
|
|
extern DL_IMPORT(int) PyObject_SetAttrString Py_PROTO((PyObject *, char *, PyObject *));
|
|
extern DL_IMPORT(int) PyObject_HasAttrString Py_PROTO((PyObject *, char *));
|
|
extern DL_IMPORT(PyObject *) PyObject_GetAttr Py_PROTO((PyObject *, PyObject *));
|
|
extern DL_IMPORT(int) PyObject_SetAttr Py_PROTO((PyObject *, PyObject *, PyObject *));
|
|
extern DL_IMPORT(int) PyObject_HasAttr Py_PROTO((PyObject *, PyObject *));
|
|
extern DL_IMPORT(long) PyObject_Hash Py_PROTO((PyObject *));
|
|
extern DL_IMPORT(int) PyObject_IsTrue Py_PROTO((PyObject *));
|
|
extern DL_IMPORT(int) PyObject_Not Py_PROTO((PyObject *));
|
|
extern DL_IMPORT(int) PyCallable_Check Py_PROTO((PyObject *));
|
|
extern DL_IMPORT(int) PyNumber_Coerce Py_PROTO((PyObject **, PyObject **));
|
|
extern DL_IMPORT(int) PyNumber_CoerceEx Py_PROTO((PyObject **, PyObject **));
|
|
|
|
/* Helpers for printing recursive container types */
|
|
extern DL_IMPORT(int) Py_ReprEnter Py_PROTO((PyObject *));
|
|
extern DL_IMPORT(void) Py_ReprLeave Py_PROTO((PyObject *));
|
|
|
|
/* tstate dict key for PyObject_Compare helper */
|
|
extern PyObject *_PyCompareState_Key;
|
|
|
|
/* Flag bits for printing: */
|
|
#define Py_PRINT_RAW 1 /* No string quotes etc. */
|
|
|
|
/*
|
|
|
|
Type flags (tp_flags)
|
|
|
|
These flags are used to extend the type structure in a backwards-compatible
|
|
fashion. Extensions can use the flags to indicate (and test) when a given
|
|
type structure contains a new feature. The Python core will use these when
|
|
introducing new functionality between major revisions (to avoid mid-version
|
|
changes in the PYTHON_API_VERSION).
|
|
|
|
Arbitration of the flag bit positions will need to be coordinated among
|
|
all extension writers who publically release their extensions (this will
|
|
be fewer than you might expect!)..
|
|
|
|
Python 1.5.2 introduced the bf_getcharbuffer slot into PyBufferProcs.
|
|
|
|
Type definitions should use Py_TPFLAGS_DEFAULT for their tp_flags value.
|
|
|
|
Code can use PyType_HasFeature(type_ob, flag_value) to test whether the
|
|
given type object has a specified feature.
|
|
|
|
*/
|
|
|
|
/* PyBufferProcs contains bf_getcharbuffer */
|
|
#define Py_TPFLAGS_HAVE_GETCHARBUFFER (1L<<0)
|
|
|
|
/* PySequenceMethods contains sq_contains */
|
|
#define Py_TPFLAGS_HAVE_SEQUENCE_IN (1L<<1)
|
|
|
|
/* Objects which participate in garbage collection (see objimp.h) */
|
|
#ifdef WITH_CYCLE_GC
|
|
#define Py_TPFLAGS_GC (1L<<2)
|
|
#else
|
|
#define Py_TPFLAGS_GC 0
|
|
#endif
|
|
|
|
#define Py_TPFLAGS_DEFAULT (Py_TPFLAGS_HAVE_GETCHARBUFFER | \
|
|
Py_TPFLAGS_HAVE_SEQUENCE_IN)
|
|
|
|
#define PyType_HasFeature(t,f) (((t)->tp_flags & (f)) != 0)
|
|
|
|
|
|
/*
|
|
The macros Py_INCREF(op) and Py_DECREF(op) are used to increment or decrement
|
|
reference counts. Py_DECREF calls the object's deallocator function; for
|
|
objects that don't contain references to other objects or heap memory
|
|
this can be the standard function free(). Both macros can be used
|
|
whereever a void expression is allowed. The argument shouldn't be a
|
|
NIL pointer. The macro _Py_NewReference(op) is used only to initialize
|
|
reference counts to 1; it is defined here for convenience.
|
|
|
|
We assume that the reference count field can never overflow; this can
|
|
be proven when the size of the field is the same as the pointer size
|
|
but even with a 16-bit reference count field it is pretty unlikely so
|
|
we ignore the possibility. (If you are paranoid, make it a long.)
|
|
|
|
Type objects should never be deallocated; the type pointer in an object
|
|
is not considered to be a reference to the type object, to save
|
|
complications in the deallocation function. (This is actually a
|
|
decision that's up to the implementer of each new type so if you want,
|
|
you can count such references to the type object.)
|
|
|
|
*** WARNING*** The Py_DECREF macro must have a side-effect-free argument
|
|
since it may evaluate its argument multiple times. (The alternative
|
|
would be to mace it a proper function or assign it to a global temporary
|
|
variable first, both of which are slower; and in a multi-threaded
|
|
environment the global variable trick is not safe.)
|
|
*/
|
|
|
|
#ifdef Py_TRACE_REFS
|
|
#ifndef Py_REF_DEBUG
|
|
#define Py_REF_DEBUG
|
|
#endif
|
|
#endif
|
|
|
|
#ifdef Py_TRACE_REFS
|
|
extern DL_IMPORT(void) _Py_Dealloc Py_PROTO((PyObject *));
|
|
extern DL_IMPORT(void) _Py_NewReference Py_PROTO((PyObject *));
|
|
extern DL_IMPORT(void) _Py_ForgetReference Py_PROTO((PyObject *));
|
|
extern DL_IMPORT(void) _Py_PrintReferences Py_PROTO((FILE *));
|
|
extern DL_IMPORT(void) _Py_ResetReferences Py_PROTO((void));
|
|
#endif
|
|
|
|
#ifndef Py_TRACE_REFS
|
|
#ifdef COUNT_ALLOCS
|
|
#define _Py_Dealloc(op) ((op)->ob_type->tp_free++, (*(op)->ob_type->tp_dealloc)((PyObject *)(op)))
|
|
#define _Py_ForgetReference(op) ((op)->ob_type->tp_free++)
|
|
#else /* !COUNT_ALLOCS */
|
|
#define _Py_Dealloc(op) (*(op)->ob_type->tp_dealloc)((PyObject *)(op))
|
|
#define _Py_ForgetReference(op) /*empty*/
|
|
#endif /* !COUNT_ALLOCS */
|
|
#endif /* !Py_TRACE_REFS */
|
|
|
|
#ifdef COUNT_ALLOCS
|
|
extern DL_IMPORT(void) inc_count Py_PROTO((PyTypeObject *));
|
|
#endif
|
|
|
|
#ifdef Py_REF_DEBUG
|
|
|
|
extern DL_IMPORT(long) _Py_RefTotal;
|
|
|
|
#ifndef Py_TRACE_REFS
|
|
#ifdef COUNT_ALLOCS
|
|
#define _Py_NewReference(op) (inc_count((op)->ob_type), _Py_RefTotal++, (op)->ob_refcnt = 1)
|
|
#else
|
|
#define _Py_NewReference(op) (_Py_RefTotal++, (op)->ob_refcnt = 1)
|
|
#endif
|
|
#endif /* !Py_TRACE_REFS */
|
|
|
|
#define Py_INCREF(op) (_Py_RefTotal++, (op)->ob_refcnt++)
|
|
#define Py_DECREF(op) \
|
|
if (--_Py_RefTotal, --(op)->ob_refcnt != 0) \
|
|
; \
|
|
else \
|
|
_Py_Dealloc((PyObject *)(op))
|
|
#else /* !Py_REF_DEBUG */
|
|
|
|
#ifdef COUNT_ALLOCS
|
|
#define _Py_NewReference(op) (inc_count((op)->ob_type), (op)->ob_refcnt = 1)
|
|
#else
|
|
#define _Py_NewReference(op) ((op)->ob_refcnt = 1)
|
|
#endif
|
|
|
|
#define Py_INCREF(op) ((op)->ob_refcnt++)
|
|
#define Py_DECREF(op) \
|
|
if (--(op)->ob_refcnt != 0) \
|
|
; \
|
|
else \
|
|
_Py_Dealloc((PyObject *)(op))
|
|
#endif /* !Py_REF_DEBUG */
|
|
|
|
/* Macros to use in case the object pointer may be NULL: */
|
|
|
|
#define Py_XINCREF(op) if ((op) == NULL) ; else Py_INCREF(op)
|
|
#define Py_XDECREF(op) if ((op) == NULL) ; else Py_DECREF(op)
|
|
|
|
/* Definition of NULL, so you don't have to include <stdio.h> */
|
|
|
|
#ifndef NULL
|
|
#define NULL 0
|
|
#endif
|
|
|
|
|
|
/*
|
|
_Py_NoneStruct is an object of undefined type which can be used in contexts
|
|
where NULL (nil) is not suitable (since NULL often means 'error').
|
|
|
|
Don't forget to apply Py_INCREF() when returning this value!!!
|
|
*/
|
|
|
|
extern DL_IMPORT(PyObject) _Py_NoneStruct; /* Don't use this directly */
|
|
|
|
#define Py_None (&_Py_NoneStruct)
|
|
|
|
|
|
/*
|
|
A common programming style in Python requires the forward declaration
|
|
of static, initialized structures, e.g. for a type object that is used
|
|
by the functions whose address must be used in the initializer.
|
|
Some compilers (notably SCO ODT 3.0, I seem to remember early AIX as
|
|
well) botch this if you use the static keyword for both declarations
|
|
(they allocate two objects, and use the first, uninitialized one until
|
|
the second declaration is encountered). Therefore, the forward
|
|
declaration should use the 'forwardstatic' keyword. This expands to
|
|
static on most systems, but to extern on a few. The actual storage
|
|
and name will still be static because the second declaration is
|
|
static, so no linker visible symbols will be generated. (Standard C
|
|
compilers take offense to the extern forward declaration of a static
|
|
object, so I can't just put extern in all cases. :-( )
|
|
*/
|
|
|
|
#ifdef BAD_STATIC_FORWARD
|
|
#define staticforward extern
|
|
#ifdef __SC__
|
|
#define statichere
|
|
#else
|
|
#define statichere static
|
|
#endif /* __SC__ */
|
|
#else /* !BAD_STATIC_FORWARD */
|
|
#define staticforward static
|
|
#define statichere static
|
|
#endif /* !BAD_STATIC_FORWARD */
|
|
|
|
|
|
/*
|
|
More conventions
|
|
================
|
|
|
|
Argument Checking
|
|
-----------------
|
|
|
|
Functions that take objects as arguments normally don't check for nil
|
|
arguments, but they do check the type of the argument, and return an
|
|
error if the function doesn't apply to the type.
|
|
|
|
Failure Modes
|
|
-------------
|
|
|
|
Functions may fail for a variety of reasons, including running out of
|
|
memory. This is communicated to the caller in two ways: an error string
|
|
is set (see errors.h), and the function result differs: functions that
|
|
normally return a pointer return NULL for failure, functions returning
|
|
an integer return -1 (which could be a legal return value too!), and
|
|
other functions return 0 for success and -1 for failure.
|
|
Callers should always check for errors before using the result.
|
|
|
|
Reference Counts
|
|
----------------
|
|
|
|
It takes a while to get used to the proper usage of reference counts.
|
|
|
|
Functions that create an object set the reference count to 1; such new
|
|
objects must be stored somewhere or destroyed again with Py_DECREF().
|
|
Functions that 'store' objects such as PyTuple_SetItem() and
|
|
PyDict_SetItemString()
|
|
don't increment the reference count of the object, since the most
|
|
frequent use is to store a fresh object. Functions that 'retrieve'
|
|
objects such as PyTuple_GetItem() and PyDict_GetItemString() also
|
|
don't increment
|
|
the reference count, since most frequently the object is only looked at
|
|
quickly. Thus, to retrieve an object and store it again, the caller
|
|
must call Py_INCREF() explicitly.
|
|
|
|
NOTE: functions that 'consume' a reference count like
|
|
PyList_SetItemString() even consume the reference if the object wasn't
|
|
stored, to simplify error handling.
|
|
|
|
It seems attractive to make other functions that take an object as
|
|
argument consume a reference count; however this may quickly get
|
|
confusing (even the current practice is already confusing). Consider
|
|
it carefully, it may save lots of calls to Py_INCREF() and Py_DECREF() at
|
|
times.
|
|
*/
|
|
|
|
/*
|
|
trashcan
|
|
CT 2k0130
|
|
non-recursively destroy nested objects
|
|
|
|
CT 2k0223
|
|
redefinition for better locality and less overhead.
|
|
|
|
Objects that want to be recursion safe need to use
|
|
the macroes
|
|
Py_TRASHCAN_SAFE_BEGIN(name)
|
|
and
|
|
Py_TRASHCAN_SAFE_END(name)
|
|
surrounding their actual deallocation code.
|
|
|
|
It would be nice to do this using the thread state.
|
|
Also, we could do an exact stack measure then.
|
|
Unfortunately, deallocations also take place when
|
|
the thread state is undefined.
|
|
|
|
CT 2k0422 complete rewrite.
|
|
There is no need to allocate new objects.
|
|
Everything is done vialob_refcnt and ob_type now.
|
|
Adding support for free-threading should be easy, too.
|
|
*/
|
|
|
|
#define PyTrash_UNWIND_LEVEL 50
|
|
|
|
#define Py_TRASHCAN_SAFE_BEGIN(op) \
|
|
{ \
|
|
++_PyTrash_delete_nesting; \
|
|
if (_PyTrash_delete_nesting < PyTrash_UNWIND_LEVEL) { \
|
|
|
|
#define Py_TRASHCAN_SAFE_END(op) \
|
|
;} \
|
|
else \
|
|
_PyTrash_deposit_object((PyObject*)op);\
|
|
--_PyTrash_delete_nesting; \
|
|
if (_PyTrash_delete_later && _PyTrash_delete_nesting <= 0) \
|
|
_PyTrash_destroy_chain(); \
|
|
} \
|
|
|
|
extern DL_IMPORT(void) _PyTrash_deposit_object Py_PROTO((PyObject*));
|
|
extern DL_IMPORT(void) _PyTrash_destroy_chain Py_PROTO(());
|
|
|
|
extern DL_IMPORT(int) _PyTrash_delete_nesting;
|
|
extern DL_IMPORT(PyObject *) _PyTrash_delete_later;
|
|
|
|
/* swap the "xx" to check the speed loss */
|
|
|
|
#define xxPy_TRASHCAN_SAFE_BEGIN(op)
|
|
#define xxPy_TRASHCAN_SAFE_END(op) ;
|
|
|
|
#ifdef __cplusplus
|
|
}
|
|
#endif
|
|
#endif /* !Py_OBJECT_H */
|