[p5sagit/p5-mst-13.2.git] / ext / Hash / Util / FieldHash / FieldHash.xs

#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"

/* support for Hash::Util::FieldHash, prefix HUF_ */

/* A Perl sub that returns a hashref to the object registry */
#define HUF_OB_REG "Hash::Util::FieldHash::_ob_reg"
/* Magic cookies to recognize object id's.  Hi, Eva, David */
#define HUF_COOKIE 2805.1980
#define HUF_REFADDR_COOKIE 1811.1976

/* For global cache of object registry */
#define MY_CXT_KEY "Hash::Util::FieldHash::_guts" XS_VERSION
typedef struct {
    HV* ob_reg; /* Cache object registry */
} my_cxt_t;
START_MY_CXT

/* Inquire the object registry (a lexical hash) from perl */
HV* HUF_get_ob_reg(void) {
    dSP;
    I32 items = call_pv(HUF_OB_REG, G_SCALAR|G_NOARGS);
    SPAGAIN;
    if (items == 1) {
        SV* ref = POPs;
        PUTBACK;
        if (ref && SvROK(ref) && SvTYPE(SvRV(ref)) == SVt_PVHV)
            return (HV*)SvRV(ref);
    }
    Perl_die(aTHX_ "Can't get object registry hash");
}

/* Deal with global context */
#define HUF_INIT 1
#define HUF_CLONE 0
#define HUF_RESET -1

void HUF_global(I32 how) {
    if (how == HUF_INIT) {
        MY_CXT_INIT;
        MY_CXT.ob_reg = HUF_get_ob_reg();
    } else if (how == HUF_CLONE) {
        MY_CXT_CLONE;
        MY_CXT.ob_reg = HUF_get_ob_reg();
    } else if (how == HUF_RESET) {
        dMY_CXT;
        MY_CXT.ob_reg = HUF_get_ob_reg();
    }
}

/* the id as an SV, optionally marked in the nv (unused feature) */
SV* HUF_id(SV* ref, NV cookie) {
    SV* id = sv_newmortal();
    if (cookie == 0 ) {
        SvUPGRADE(id, SVt_PVIV);
    } else {
        SvUPGRADE(id, SVt_PVNV);
        SvNV_set(id, cookie);
        SvNOK_on(id);
    }
    SvIV_set(id, PTR2UV(SvRV(ref)));
    SvIOK_on(id);
    return id;
}

/* plain id, only used for field hash entries in field lists */
SV* HUF_field_id(SV* obj) {
    return HUF_id(obj, 0.0);
}

/* object id (same as plain, may be different in future) */
SV* HUF_obj_id(SV* obj) {
    return HUF_id(obj, 0.0);
}

/* set up uvar magic for any sv */
void HUF_add_uvar_magic(
    SV* sv,                    /* the sv to enchant, visible to get/set */
    I32(* val)(pTHX_ IV, SV*), /* "get" function */
    I32(* set)(pTHX_ IV, SV*), /* "set" function */
    I32 index,                 /* get/set will see this */
    SV* thing                  /* any associated info */
) {
    struct ufuncs uf;
        uf.uf_val = val;
        uf.uf_set = set;
        uf.uf_index = index;
    sv_magic(sv, thing, PERL_MAGIC_uvar, (char*)&uf, sizeof(uf));
}

/* Fetch the data container of a trigger */
AV* HUF_get_trigger_content(SV* trigger) {
    MAGIC* mg;
    if (trigger && (mg = mg_find(trigger, PERL_MAGIC_uvar)))
        return (AV*)mg->mg_obj;
    return NULL;
}

/* Delete an object from all field hashes it may occur in.  Also delete
 * the object's entry from the object registry.  This function goes in
 * the uf_set field of the uvar magic of a trigger.
 */
I32 HUF_destroy_obj(pTHX_ IV index, SV* trigger) {
    /* Do nothing if the weakref wasn't undef'd.  Also don't bother
     * during global destruction.  (MY_CXT.ob_reg is sometimes funny there) */
    if (!SvROK(trigger) && (!PL_in_clean_all)) {
        dMY_CXT;
        AV* cont = HUF_get_trigger_content(trigger);
        SV* ob_id = *av_fetch(cont, 0, 0);
        HV* field_tab = (HV*) *av_fetch(cont, 1, 0);
        HE* ent;
        hv_iterinit(field_tab);
        while (ent = hv_iternext(field_tab)) {
            SV* field_ref = HeVAL(ent);
            SV* field = SvRV(field_ref);
            hv_delete_ent((HV*)field, ob_id, G_DISCARD, 0);
        }
        /* make it safe in case we must run in global clenaup, after all */
        if (PL_in_clean_all)
            HUF_global(HUF_RESET);
        hv_delete_ent(MY_CXT.ob_reg, ob_id, G_DISCARD, 0);
    }
    return 0;
}

/* Create a trigger for an object.  The trigger is a magical weak ref
 * that fires when the weak ref expires.  it holds the original id of
 * the object, and a list of field hashes from which the object may
 * have to be deleted.  The trigger is stored in the object registry
 * and also deleted when the object expires.
 */
SV* HUF_new_trigger(SV* obj, SV* ob_id) {
    dMY_CXT;
    SV* trigger = sv_rvweaken(newRV_inc(SvRV(obj)));
    AV* cont = newAV();
    sv_2mortal((SV*)cont);
    av_store(cont, 0, SvREFCNT_inc(ob_id));
    av_store(cont, 1, (SV*)newHV());
    HUF_add_uvar_magic(trigger, NULL, &HUF_destroy_obj, 0, (SV*)cont);
    hv_store_ent(MY_CXT.ob_reg, ob_id, trigger, 0);
    return trigger;
}

/* retrieve a trigger for obj if one exists, return NULL otherwise */
SV* HUF_ask_trigger(SV* ob_id) {
    dMY_CXT;
    HE* ent;
    if (ent = hv_fetch_ent(MY_CXT.ob_reg, ob_id, 0, 0))
        return HeVAL(ent);
    return NULL;
}

/* get the trigger for an object, creating it if necessary */
SV* HUF_get_trigger(SV* obj, SV* ob_id) {
    SV* trigger;
    if (!(trigger = HUF_ask_trigger(ob_id)))
        trigger = HUF_new_trigger(obj, ob_id);
    return trigger;
}

/* mark an object (trigger) as having been used with a field */
void HUF_mark_field(SV* trigger, SV* field) {
    AV* cont = HUF_get_trigger_content(trigger);
    HV* field_tab = (HV*) *av_fetch(cont, 1, 0);
    SV* field_ref = newRV_inc(field);
    SV* field_id = HUF_field_id(field_ref);
    hv_store_ent(field_tab, field_id, field_ref, 0);
}

/* These constants are not in the API.  If they ever change in hv.c this code
 * must be updated */
#define HV_FETCH_ISSTORE   0x01
#define HV_FETCH_ISEXISTS  0x02
#define HV_FETCH_LVALUE    0x04
#define HV_FETCH_JUST_SV   0x08

#define HUF_WOULD_CREATE_KEY(x) ((x) != -1 && ((x) & (HV_FETCH_ISSTORE | HV_FETCH_LVALUE)))

/* The key exchange function.  It communicates with S_hv_magic_uvar_xkey
 * in hv.c */
I32 HUF_watch_key(pTHX_ IV action, SV* field) {
    MAGIC* mg = mg_find(field, PERL_MAGIC_uvar);
    SV* keysv;
    if (!mg)
        Perl_die(aTHX_ "Rogue call of 'HUF_watch_key'");
    keysv = mg->mg_obj;
    if (keysv && SvROK(keysv)) {
        SV* ob_id = HUF_obj_id(keysv);
        mg->mg_obj = ob_id; /* key replacement */
        if (HUF_WOULD_CREATE_KEY(action)) {
            SV* trigger = HUF_get_trigger(keysv, ob_id);
            HUF_mark_field(trigger, field);
        }
    }
    return 0;
}

/* see if something is a field hash */
int HUF_get_status(HV* hash) {
    int ans = 0;
    if (hash && (SvTYPE(hash) == SVt_PVHV)) {
        MAGIC* mg;
        struct ufuncs* uf;
        ans = (mg = mg_find((SV*)hash, PERL_MAGIC_uvar)) &&
            (uf = (struct ufuncs *)mg->mg_ptr) &&
            (uf->uf_val == &HUF_watch_key) &&
            (uf->uf_set == NULL);
    }
    return ans;
}

/* Thread support.  These routines are called by CLONE (and nothing else) */

/* Fix entries for one object in all field hashes */
void HUF_fix_trigger(SV* trigger, SV* new_id) {
    AV* cont = HUF_get_trigger_content(trigger);
    HV* field_tab = (HV*) *av_fetch(cont, 1, 0);
    HV* new_tab = newHV();
    HE* ent;
    SV* old_id = *av_fetch(cont, 0, 0);
    hv_iterinit(field_tab);
    while (ent = hv_iternext(field_tab)) {
        SV* field_ref = HeVAL(ent);
        SV* field_id = HUF_field_id(field_ref);
        HV* field = (HV*)SvRV(field_ref);
        SV* val;
        /* recreate field tab entry */
        hv_store_ent(new_tab, field_id, SvREFCNT_inc(field_ref), 0);
        /* recreate field entry, if any */
        if (val = hv_delete_ent(field, old_id, 0, 0))
            hv_store_ent(field, new_id, SvREFCNT_inc(val), 0);
    }
    /* update the trigger */
    av_store(cont, 0, SvREFCNT_inc(new_id));
    av_store(cont, 1, (SV*)new_tab);
}

/* Go over object registry and fix all objects.  Also fix the object
 * registry.
 */
void HUF_fix_objects(void) {
    dMY_CXT;
    I32 i, len;
    HE* ent;
    AV* oblist = (AV*)sv_2mortal((SV*)newAV());
    hv_iterinit(MY_CXT.ob_reg);
    while(ent = hv_iternext(MY_CXT.ob_reg))
        av_push(oblist, SvREFCNT_inc(hv_iterkeysv(ent)));
    len = av_len(oblist);
    for (i = 0; i <= len; ++i) {
        SV* old_id = *av_fetch(oblist, i, 0);
        SV* trigger = hv_delete_ent(MY_CXT.ob_reg, old_id, 0, 0);
        SV* new_id = HUF_obj_id(trigger);
        HUF_fix_trigger(trigger, new_id);
        hv_store_ent(MY_CXT.ob_reg, new_id, SvREFCNT_inc(trigger), 0);
    }
}

/* test support (not needed for functionality) */

static SV* counter;
I32 HUF_inc_var(pTHX_ IV index, SV* which) {
    sv_setiv(counter, 1 + SvIV(counter));
    return 0;
}

MODULE = Hash::Util::FieldHash          PACKAGE = Hash::Util::FieldHash

BOOT:
{
    HUF_global(HUF_INIT); /* create variables */
}

int
_fieldhash(SV* href, int mode)
PROTOTYPE: $$
CODE:
    HV* field;
    RETVAL = 0;
    if (mode &&
        href && SvROK(href) &&
        (field = (HV*)SvRV(href)) &&
        SvTYPE(field) == SVt_PVHV
    ) {
        HUF_add_uvar_magic(
            SvRV(href),
            &HUF_watch_key,
            NULL,
            0,
            NULL
        );
        RETVAL = HUF_get_status(field);
    }
OUTPUT:
    RETVAL

void
CLONE(char* class)
CODE:
    if (0 == strcmp(class, "Hash::Util::FieldHash")) {
        HUF_global(HUF_CLONE);
        HUF_fix_objects();
    }

void
_active_fields(SV* obj)
PPCODE:
    if (SvROK(obj)) {
        SV* ob_id = HUF_obj_id(obj);
        SV* trigger = HUF_ask_trigger(ob_id);
        if (trigger) {
            AV* cont = HUF_get_trigger_content(trigger);
            HV* field_tab = (HV*) *av_fetch(cont, 1, 0);
            HE* ent;
            hv_iterinit(field_tab);
            while (ent = hv_iternext(field_tab)) {
                HV* field = (HV*)SvRV(HeVAL(ent));
                if (hv_exists_ent(field, ob_id, 0))
                    XPUSHs(sv_2mortal(newRV_inc((SV*)field)));
            }
        }
    }

void
_test_uvar_get(SV* svref, SV* countref)
CODE:
    if (SvROK(svref) && SvROK(countref)) {
        counter = SvRV(countref);
        sv_setiv(counter, 0);
        HUF_add_uvar_magic(
            SvRV(svref),
            &HUF_inc_var,
            NULL,
            0,
            SvRV(countref)
        );
    }

void
_test_uvar_set(SV* svref, SV* countref)
CODE:
    if (SvROK(svref) && SvROK(countref)) {
        counter = SvRV(countref);
        sv_setiv(counter, 0);
        counter = SvRV(countref);
        HUF_add_uvar_magic(
            SvRV(svref),
            NULL,
            &HUF_inc_var,
            0,
            SvRV(countref)
        );
    }

void
_test_uvar_same(SV* svref, SV* countref)
CODE:
    if (SvROK(svref) && SvROK(countref)) {
        counter = SvRV(countref);
        sv_setiv(counter, 0);
        HUF_add_uvar_magic(
            SvRV(svref),
            &HUF_inc_var,
            &HUF_inc_var,
            0,
            NULL
        );
    }
Commit	Line	Data
1e73acc8	1	#include "EXTERN.h"
	2	#include "perl.h"
	3	#include "XSUB.h"
	4
	5	/* support for Hash::Util::FieldHash, prefix HUF_ */
	6
6ff38c27	7	/* A Perl sub that returns a hashref to the object registry */
6ff38c27	8	#define HUF_OB_REG "Hash::Util::FieldHash::_ob_reg"
1e73acc8	9	/* Magic cookies to recognize object id's. Hi, Eva, David */
	10	#define HUF_COOKIE 2805.1980
	11	#define HUF_REFADDR_COOKIE 1811.1976
	12
1e73acc8	13	/* For global cache of object registry */
	14	#define MY_CXT_KEY "Hash::Util::FieldHash::_guts" XS_VERSION
	15	typedef struct {
	16	HV* ob_reg; /* Cache object registry */
	17	} my_cxt_t;
	18	START_MY_CXT
	19
6ff38c27	20	/* Inquire the object registry (a lexical hash) from perl */
	21	HV* HUF_get_ob_reg(void) {
	22	dSP;
	23	I32 items = call_pv(HUF_OB_REG, G_SCALAR\|G_NOARGS);
	24	SPAGAIN;
	25	if (items == 1) {
	26	SV* ref = POPs;
	27	PUTBACK;
	28	if (ref && SvROK(ref) && SvTYPE(SvRV(ref)) == SVt_PVHV)
	29	return (HV*)SvRV(ref);
	30	}
	31	Perl_die(aTHX_ "Can't get object registry hash");
	32	}
	33
1e73acc8	34	/* Deal with global context */
	35	#define HUF_INIT 1
	36	#define HUF_CLONE 0
	37	#define HUF_RESET -1
	38
	39	void HUF_global(I32 how) {
	40	if (how == HUF_INIT) {
	41	MY_CXT_INIT;
6ff38c27	42	MY_CXT.ob_reg = HUF_get_ob_reg();
1e73acc8	43	} else if (how == HUF_CLONE) {
1e73acc8	44	MY_CXT_CLONE;
6ff38c27	45	MY_CXT.ob_reg = HUF_get_ob_reg();
1e73acc8	46	} else if (how == HUF_RESET) {
1e73acc8	47	dMY_CXT;
6ff38c27	48	MY_CXT.ob_reg = HUF_get_ob_reg();
1e73acc8	49	}
	50	}
	51
	52	/* the id as an SV, optionally marked in the nv (unused feature) */
	53	SV* HUF_id(SV* ref, NV cookie) {
	54	SV* id = sv_newmortal();
	55	if (cookie == 0 ) {
	56	SvUPGRADE(id, SVt_PVIV);
	57	} else {
	58	SvUPGRADE(id, SVt_PVNV);
	59	SvNV_set(id, cookie);
	60	SvNOK_on(id);
	61	}
ce809d1f	62	SvIV_set(id, PTR2UV(SvRV(ref)));
1e73acc8	63	SvIOK_on(id);
	64	return id;
	65	}
	66
	67	/* plain id, only used for field hash entries in field lists */
	68	SV* HUF_field_id(SV* obj) {
	69	return HUF_id(obj, 0.0);
	70	}
	71
6ff38c27	72	/* object id (same as plain, may be different in future) */
1e73acc8	73	SV* HUF_obj_id(SV* obj) {
	74	return HUF_id(obj, 0.0);
	75	}
	76
	77	/* set up uvar magic for any sv */
	78	void HUF_add_uvar_magic(
6ff38c27	79	SV* sv, /* the sv to enchant, visible to get/set */
1e73acc8	80	I32(* val)(pTHX_ IV, SV), / "get" function */
	81	I32(* set)(pTHX_ IV, SV), / "set" function */
	82	I32 index, /* get/set will see this */
	83	SV* thing /* any associated info */
	84	) {
1e73acc8	85	struct ufuncs uf;
	86	uf.uf_val = val;
	87	uf.uf_set = set;
	88	uf.uf_index = index;
	89	sv_magic(sv, thing, PERL_MAGIC_uvar, (char*)&uf, sizeof(uf));
	90	}
	91
	92	/* Fetch the data container of a trigger */
	93	AV* HUF_get_trigger_content(SV* trigger) {
	94	MAGIC* mg;
	95	if (trigger && (mg = mg_find(trigger, PERL_MAGIC_uvar)))
	96	return (AV*)mg->mg_obj;
	97	return NULL;
	98	}
	99
	100	/* Delete an object from all field hashes it may occur in. Also delete
c418a2d4	101	* the object's entry from the object registry. This function goes in
c418a2d4	102	* the uf_set field of the uvar magic of a trigger.
1e73acc8	103	*/
	104	I32 HUF_destroy_obj(pTHX_ IV index, SV* trigger) {
	105	/* Do nothing if the weakref wasn't undef'd. Also don't bother
	106	* during global destruction. (MY_CXT.ob_reg is sometimes funny there) */
	107	if (!SvROK(trigger) && (!PL_in_clean_all)) {
	108	dMY_CXT;
	109	AV* cont = HUF_get_trigger_content(trigger);
	110	SV* ob_id = *av_fetch(cont, 0, 0);
	111	HV* field_tab = (HV) av_fetch(cont, 1, 0);
	112	HE* ent;
	113	hv_iterinit(field_tab);
	114	while (ent = hv_iternext(field_tab)) {
	115	SV* field_ref = HeVAL(ent);
	116	SV* field = SvRV(field_ref);
	117	hv_delete_ent((HV*)field, ob_id, G_DISCARD, 0);
	118	}
	119	/* make it safe in case we must run in global clenaup, after all */
	120	if (PL_in_clean_all)
	121	HUF_global(HUF_RESET);
	122	hv_delete_ent(MY_CXT.ob_reg, ob_id, G_DISCARD, 0);
	123	}
	124	return 0;
	125	}
	126
	127	/* Create a trigger for an object. The trigger is a magical weak ref
	128	* that fires when the weak ref expires. it holds the original id of
	129	* the object, and a list of field hashes from which the object may
	130	* have to be deleted. The trigger is stored in the object registry
	131	* and also deleted when the object expires.
	132	*/
	133	SV* HUF_new_trigger(SV* obj, SV* ob_id) {
	134	dMY_CXT;
	135	SV* trigger = sv_rvweaken(newRV_inc(SvRV(obj)));
	136	AV* cont = newAV();
	137	sv_2mortal((SV*)cont);
	138	av_store(cont, 0, SvREFCNT_inc(ob_id));
	139	av_store(cont, 1, (SV*)newHV());
	140	HUF_add_uvar_magic(trigger, NULL, &HUF_destroy_obj, 0, (SV*)cont);
	141	hv_store_ent(MY_CXT.ob_reg, ob_id, trigger, 0);
	142	return trigger;
	143	}
	144
	145	/* retrieve a trigger for obj if one exists, return NULL otherwise */
	146	SV* HUF_ask_trigger(SV* ob_id) {
	147	dMY_CXT;
	148	HE* ent;
	149	if (ent = hv_fetch_ent(MY_CXT.ob_reg, ob_id, 0, 0))
	150	return HeVAL(ent);
	151	return NULL;
	152	}
	153
	154	/* get the trigger for an object, creating it if necessary */
	155	SV* HUF_get_trigger(SV* obj, SV* ob_id) {
	156	SV* trigger;
	157	if (!(trigger = HUF_ask_trigger(ob_id)))
	158	trigger = HUF_new_trigger(obj, ob_id);
	159	return trigger;
	160	}
	161
	162	/* mark an object (trigger) as having been used with a field */
	163	void HUF_mark_field(SV* trigger, SV* field) {
	164	AV* cont = HUF_get_trigger_content(trigger);
	165	HV* field_tab = (HV) av_fetch(cont, 1, 0);
	166	SV* field_ref = newRV_inc(field);
167	SV* field_id = HUF_field_id(field_ref);
168	hv_store_ent(field_tab, field_id, field_ref, 0);
169	}
170
6ff38c27	171	/* These constants are not in the API. If they ever change in hv.c this code
6ff38c27	172	* must be updated */
a607227a	173	#define HV_FETCH_ISSTORE 0x01
	174	#define HV_FETCH_ISEXISTS 0x02
	175	#define HV_FETCH_LVALUE 0x04
	176	#define HV_FETCH_JUST_SV 0x08
	177
	178	#define HUF_WOULD_CREATE_KEY(x) ((x) != -1 && ((x) & (HV_FETCH_ISSTORE \| HV_FETCH_LVALUE)))
	179
1e73acc8	180	/* The key exchange function. It communicates with S_hv_magic_uvar_xkey
1e73acc8	181	* in hv.c */
1748121c	182	I32 HUF_watch_key(pTHX_ IV action, SV* field) {
1e73acc8	183	MAGIC* mg = mg_find(field, PERL_MAGIC_uvar);
6ff38c27	184	SV* keysv;
	185	if (!mg)
	186	Perl_die(aTHX_ "Rogue call of 'HUF_watch_key'");
	187	keysv = mg->mg_obj;
1e73acc8	188	if (keysv && SvROK(keysv)) {
1e73acc8	189	SV* ob_id = HUF_obj_id(keysv);
1e73acc8	190	mg->mg_obj = ob_id; /* key replacement */
a607227a	191	if (HUF_WOULD_CREATE_KEY(action)) {
	192	SV* trigger = HUF_get_trigger(keysv, ob_id);
	193	HUF_mark_field(trigger, field);
	194	}
1e73acc8	195	}
	196	return 0;
	197	}
	198
	199	/* see if something is a field hash */
	200	int HUF_get_status(HV* hash) {
	201	int ans = 0;
	202	if (hash && (SvTYPE(hash) == SVt_PVHV)) {
1e73acc8	203	MAGIC* mg;
	204	struct ufuncs* uf;
	205	ans = (mg = mg_find((SV*)hash, PERL_MAGIC_uvar)) &&
	206	(uf = (struct ufuncs *)mg->mg_ptr) &&
	207	(uf->uf_val == &HUF_watch_key) &&
	208	(uf->uf_set == NULL);
	209	}
	210	return ans;
	211	}
	212
	213	/* Thread support. These routines are called by CLONE (and nothing else) */
	214
	215	/* Fix entries for one object in all field hashes */
	216	void HUF_fix_trigger(SV* trigger, SV* new_id) {
	217	AV* cont = HUF_get_trigger_content(trigger);
	218	HV* field_tab = (HV) av_fetch(cont, 1, 0);
	219	HV* new_tab = newHV();
	220	HE* ent;
	221	SV* old_id = *av_fetch(cont, 0, 0);
	222	hv_iterinit(field_tab);
	223	while (ent = hv_iternext(field_tab)) {
	224	SV* field_ref = HeVAL(ent);
	225	SV* field_id = HUF_field_id(field_ref);
	226	HV* field = (HV*)SvRV(field_ref);
	227	SV* val;
	228	/* recreate field tab entry */
	229	hv_store_ent(new_tab, field_id, SvREFCNT_inc(field_ref), 0);
	230	/* recreate field entry, if any */
	231	if (val = hv_delete_ent(field, old_id, 0, 0))
	232	hv_store_ent(field, new_id, SvREFCNT_inc(val), 0);
	233	}
	234	/* update the trigger */
	235	av_store(cont, 0, SvREFCNT_inc(new_id));
	236	av_store(cont, 1, (SV*)new_tab);
	237	}
	238
	239	/* Go over object registry and fix all objects. Also fix the object
	240	* registry.
	241	*/
ce809d1f	242	void HUF_fix_objects(void) {
1e73acc8	243	dMY_CXT;
	244	I32 i, len;
	245	HE* ent;
	246	AV* oblist = (AV)sv_2mortal((SV)newAV());
	247	hv_iterinit(MY_CXT.ob_reg);
	248	while(ent = hv_iternext(MY_CXT.ob_reg))
	249	av_push(oblist, SvREFCNT_inc(hv_iterkeysv(ent)));
	250	len = av_len(oblist);
	251	for (i = 0; i <= len; ++i) {
	252	SV* old_id = *av_fetch(oblist, i, 0);
	253	SV* trigger = hv_delete_ent(MY_CXT.ob_reg, old_id, 0, 0);
	254	SV* new_id = HUF_obj_id(trigger);
	255	HUF_fix_trigger(trigger, new_id);
	256	hv_store_ent(MY_CXT.ob_reg, new_id, SvREFCNT_inc(trigger), 0);
	257	}
	258	}
	259
	260	/* test support (not needed for functionality) */
	261
	262	static SV* counter;
1748121c	263	I32 HUF_inc_var(pTHX_ IV index, SV* which) {
1e73acc8	264	sv_setiv(counter, 1 + SvIV(counter));
	265	return 0;
	266	}
	267
	268	MODULE = Hash::Util::FieldHash PACKAGE = Hash::Util::FieldHash
	269
	270	BOOT:
	271	{
	272	HUF_global(HUF_INIT); /* create variables */
	273	}
	274
	275	int
	276	_fieldhash(SV* href, int mode)
	277	PROTOTYPE: $$
	278	CODE:
	279	HV* field;
	280	RETVAL = 0;
	281	if (mode &&
	282	href && SvROK(href) &&
	283	(field = (HV*)SvRV(href)) &&
	284	SvTYPE(field) == SVt_PVHV
	285	) {
	286	HUF_add_uvar_magic(
	287	SvRV(href),
	288	&HUF_watch_key,
	289	NULL,
	290	0,
	291	NULL
	292	);
	293	RETVAL = HUF_get_status(field);
	294	}
	295	OUTPUT:
	296	RETVAL
	297
	298	void
	299	CLONE(char* class)
	300	CODE:
	301	if (0 == strcmp(class, "Hash::Util::FieldHash")) {
	302	HUF_global(HUF_CLONE);
	303	HUF_fix_objects();
	304	}
	305
c418a2d4	306	void
1e73acc8	307	_active_fields(SV* obj)
	308	PPCODE:
	309	if (SvROK(obj)) {
	310	SV* ob_id = HUF_obj_id(obj);
	311	SV* trigger = HUF_ask_trigger(ob_id);
	312	if (trigger) {
	313	AV* cont = HUF_get_trigger_content(trigger);
	314	HV* field_tab = (HV) av_fetch(cont, 1, 0);
	315	HE* ent;
	316	hv_iterinit(field_tab);
	317	while (ent = hv_iternext(field_tab)) {
	318	HV* field = (HV*)SvRV(HeVAL(ent));
	319	if (hv_exists_ent(field, ob_id, 0))
	320	XPUSHs(sv_2mortal(newRV_inc((SV*)field)));
	321	}
	322	}
	323	}
	324
	325	void
	326	_test_uvar_get(SV* svref, SV* countref)
	327	CODE:
	328	if (SvROK(svref) && SvROK(countref)) {
	329	counter = SvRV(countref);
	330	sv_setiv(counter, 0);
	331	HUF_add_uvar_magic(
	332	SvRV(svref),
	333	&HUF_inc_var,
	334	NULL,
	335	0,
	336	SvRV(countref)
	337	);
	338	}
	339
	340	void
	341	_test_uvar_set(SV* svref, SV* countref)
	342	CODE:
	343	if (SvROK(svref) && SvROK(countref)) {
	344	counter = SvRV(countref);
	345	sv_setiv(counter, 0);
	346	counter = SvRV(countref);
	347	HUF_add_uvar_magic(
	348	SvRV(svref),
	349	NULL,
	350	&HUF_inc_var,
	351	0,
	352	SvRV(countref)
	353	);
	354	}
	355
	356	void
	357	_test_uvar_same(SV* svref, SV* countref)
	358	CODE:
	359	if (SvROK(svref) && SvROK(countref)) {
	360	counter = SvRV(countref);
	361	sv_setiv(counter, 0);
	362	HUF_add_uvar_magic(
	363	SvRV(svref),
	364	&HUF_inc_var,
	365	&HUF_inc_var,
	366	0,
	367	NULL
	368	);
	369	}
	370