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fa6933e035
Export these internal functions for test_peg_generator * _PyArena_AddPyObject() * _PyArena_Free() * _PyArena_Malloc() * _PyArena_New()
68 lines
2.8 KiB
C
68 lines
2.8 KiB
C
// An arena-like memory interface for the compiler.
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#ifndef Py_INTERNAL_PYARENA_H
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#define Py_INTERNAL_PYARENA_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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#ifndef Py_BUILD_CORE
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# error "this header requires Py_BUILD_CORE define"
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#endif
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typedef struct _arena PyArena;
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// _PyArena_New() and _PyArena_Free() create a new arena and free it,
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// respectively. Once an arena has been created, it can be used
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// to allocate memory via _PyArena_Malloc(). Pointers to PyObject can
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// also be registered with the arena via _PyArena_AddPyObject(), and the
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// arena will ensure that the PyObjects stay alive at least until
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// _PyArena_Free() is called. When an arena is freed, all the memory it
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// allocated is freed, the arena releases internal references to registered
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// PyObject*, and none of its pointers are valid.
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// XXX (tim) What does "none of its pointers are valid" mean? Does it
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// XXX mean that pointers previously obtained via _PyArena_Malloc() are
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// XXX no longer valid? (That's clearly true, but not sure that's what
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// XXX the text is trying to say.)
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//
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// _PyArena_New() returns an arena pointer. On error, it
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// returns a negative number and sets an exception.
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// XXX (tim): Not true. On error, _PyArena_New() actually returns NULL,
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// XXX and looks like it may or may not set an exception (e.g., if the
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// XXX internal PyList_New(0) returns NULL, _PyArena_New() passes that on
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// XXX and an exception is set; OTOH, if the internal
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// XXX block_new(DEFAULT_BLOCK_SIZE) returns NULL, that's passed on but
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// XXX an exception is not set in that case).
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//
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// Export for test_peg_generator
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PyAPI_FUNC(PyArena*) _PyArena_New(void);
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// Export for test_peg_generator
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PyAPI_FUNC(void) _PyArena_Free(PyArena *);
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// Mostly like malloc(), return the address of a block of memory spanning
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// `size` bytes, or return NULL (without setting an exception) if enough
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// new memory can't be obtained. Unlike malloc(0), _PyArena_Malloc() with
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// size=0 does not guarantee to return a unique pointer (the pointer
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// returned may equal one or more other pointers obtained from
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// _PyArena_Malloc()).
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// Note that pointers obtained via _PyArena_Malloc() must never be passed to
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// the system free() or realloc(), or to any of Python's similar memory-
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// management functions. _PyArena_Malloc()-obtained pointers remain valid
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// until _PyArena_Free(ar) is called, at which point all pointers obtained
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// from the arena `ar` become invalid simultaneously.
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//
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// Export for test_peg_generator
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PyAPI_FUNC(void*) _PyArena_Malloc(PyArena *, size_t size);
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// This routine isn't a proper arena allocation routine. It takes
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// a PyObject* and records it so that it can be DECREFed when the
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// arena is freed.
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//
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// Export for test_peg_generator
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PyAPI_FUNC(int) _PyArena_AddPyObject(PyArena *, PyObject *);
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#ifdef __cplusplus
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}
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#endif
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#endif /* !Py_INTERNAL_PYARENA_H */
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