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/**************************************************************************/
/* */
/* OCaml */
/* */
/* Damien Doligez, projet Para, INRIA Rocquencourt */
/* */
/* Copyright 1997 Institut National de Recherche en Informatique et */
/* en Automatique. */
/* */
/* All rights reserved. This file is distributed under the terms of */
/* the GNU Lesser General Public License version 2.1, with the */
/* special exception on linking described in the file LICENSE. */
/* */
/**************************************************************************/
/* Operations on weak arrays */
#ifndef CAML_WEAK_H
#define CAML_WEAK_H
#include "mlvalues.h"
#ifdef __cplusplus
extern "C" {
#endif
/** The requirements of the functions must be satisfied, it is
unspecified what happens if they are not. The debugging runtime
could check some of them. */
CAMLextern value caml_ephemeron_create(mlsize_t len);
/** Create an ephemeron with the given number of keys.
This function allocates.
*/
CAMLextern mlsize_t caml_ephemeron_num_keys(value eph);
/** Return the number of key in the ephemeron. The valid key offset goes
from [0] to the predecessor of the returned value. */
CAMLextern int caml_ephemeron_key_is_set(value eph, mlsize_t offset);
/** Return 1 if the key in the ephemeron at the given offset is set.
Otherwise 0. The value [eph] must be an ephemeron and [offset] a
valid key offset.
*/
CAMLextern void caml_ephemeron_set_key(value eph, mlsize_t offset, value k);
/** Set the key of the given ephemeron [eph] at the given offset
[offset] to the given value [k]. The value [eph] must be an
ephemeron, [offset] a valid key offset and [k] a block.
*/
CAMLextern void caml_ephemeron_unset_key(value eph, mlsize_t offset);
/** Unset the key of the given ephemeron at the given offset. The
value [eph] must be an ephemeron and [offset] a valid key offset.
*/
CAMLextern int caml_ephemeron_get_key(value eph, mlsize_t offset, value *key);
/** Return 1 if the key in the ephemeron at the given offset is set.
Otherwise 0. When returning 1, set [*key] to the pointed value.
The value [eph] must be an ephemeron and [offset] a valid key
offset.
*/
CAMLextern int caml_ephemeron_get_key_copy(value eph, mlsize_t offset,
value *key);
/** Return 1 if the key in the ephemeron at the given offset is set.
Otherwise 0. When returning 1, set [*key] to a shallow copy of the
key. This function allocates.
The value [eph] must be an ephemeron and [offset] a valid key
offset.
*/
CAMLextern void caml_ephemeron_blit_key(value eph1, mlsize_t off1,
value eph2, mlsize_t off2,
mlsize_t len);
/** Fill the given range of keys of [eph2] with the given range of
keys of [eph1]. Contrary to using caml_ephemeron_get_key followed
by caml_ephemeron_set_key or caml_ephemeron_unset_key, this
function does not prevent the incremental GC from erasing the
value in its current cycle. The value [eph1] (resp. [eph2]) must
be an ephemeron and the offsets between [off1] and [off1+len]
(resp. between [off2] and [off2+offset]) must be valid keys of
[eph1] (resp. [eph2]).
*/
CAMLextern int caml_ephemeron_data_is_set(value eph);
/** Return 1 if the data in the ephemeron is set.
Otherwise 0. The value [eph] must be an ephemeron.
*/
CAMLextern void caml_ephemeron_set_data(value eph, value k);
/** Set the data of the given ephemeron [eph] to the given value
[k]. The value [eph] must be an ephemeron and [k] a block.
*/
CAMLextern void caml_ephemeron_unset_data(value eph);
/** Unset the data of the given ephemeron. The value [eph] must be an
ephemeron.
*/
CAMLextern int caml_ephemeron_get_data(value eph, value *data);
/** Return 1 if the data in the ephemeron at the given offset is set.
Otherwise 0. When returning 1, set [*data] to the pointed value.
The value [eph] must be an ephemeron and [offset] a valid key
offset.
*/
CAMLextern int caml_ephemeron_get_data_copy(value eph, value *data);
/** Return 1 if the data in the ephemeron at the given offset is set.
Otherwise 0. When returning 1, set [*data] to a shallow copy of
the data. This function allocates.
The value [eph] must be an ephemeron and [offset] a valid key
offset.
*/
CAMLextern void caml_ephemeron_blit_data(value eph1, value eph2);
/** Sets the data of [eph2] to be the same as the data of [eph1].
Contrary to using caml_ephemeron_get_data followed by
caml_ephemeron_set_data or caml_ephemeron_unset_data, this
function does not prevent the incremental GC from erasing the
value in its current cycle. The values [eph1] and [eph2] must be
ephemerons.
*/
#define caml_weak_array_length caml_ephemeron_num_keys
#define caml_weak_array_create caml_ephemeron_create
#define caml_weak_array_check caml_ephemeron_key_is_set
#define caml_weak_array_unset caml_ephemeron_unset_key
#define caml_weak_array_set caml_ephemeron_set_key
#define caml_weak_array_get caml_ephemeron_get_key
#define caml_weak_array_get_copy caml_ephemeron_get_key_copy
#define caml_weak_array_blit caml_ephemeron_blit_key
#ifdef CAML_INTERNALS
extern value caml_ephe_list_head;
extern value caml_ephe_none;
/** The first field 0: weak list;
second field 1: data;
others 2..: keys;
A weak pointer is an ephemeron with the data at caml_ephe_none
If fields are added, don't forget to update weak.ml, [additional_values],
and obj.ml, [Ephemeron.additional_values].
*/
#define CAML_EPHE_LINK_OFFSET 0
#define CAML_EPHE_DATA_OFFSET 1
#define CAML_EPHE_FIRST_KEY 2
#define CAML_EPHE_MAX_WOSIZE (Max_wosize - CAML_EPHE_FIRST_KEY)
/* In the header, in order to let major_gc.c
and weak.c see the body of the function */
static inline void caml_ephe_clean (value v){
value child;
int release_data = 0;
mlsize_t size, i;
header_t hd;
CAMLassert(caml_gc_phase == Phase_clean);
hd = Hd_val (v);
size = Wosize_hd (hd);
for (i = 2; i < size; i++){
child = Field (v, i);
ephemeron_again:
if (child != caml_ephe_none
&& Is_block (child) && Is_in_heap_or_young (child)){
if (Tag_val (child) == Forward_tag){
value f = Forward_val (child);
if (Is_block (f)) {
if (!Is_in_value_area(f) || Tag_val (f) == Forward_tag
|| Tag_val (f) == Lazy_tag || Tag_val (f) == Double_tag){
/* Do not short-circuit the pointer. */
}else{
Field (v, i) = child = f;
if (Is_block (f) && Is_young (f))
add_to_ephe_ref_table(&caml_ephe_ref_table, v, i);
goto ephemeron_again;
}
}
}
if (Is_white_val (child) && !Is_young (child)){
release_data = 1;
Field (v, i) = caml_ephe_none;
}
}
}
child = Field (v, 1);
if(child != caml_ephe_none){
if (release_data){
Field (v, 1) = caml_ephe_none;
} else {
/* The mark phase must have marked it */
CAMLassert( !(Is_block (child) && Is_in_heap (child)
&& Is_white_val (child)) );
}
}
}
#endif /* CAML_INTERNALS */
#ifdef __cplusplus
}
#endif
#endif /* CAML_WEAK_H */
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