[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;
    HV* ob_reg = NULL;
    I32 items;
    ENTER;
    SAVETMPS;

    PUSHMARK(SP);
    items = call_pv(HUF_OB_REG, G_SCALAR|G_NOARGS);
    SPAGAIN;

    if (items == 1 && TOPs && SvROK(TOPs) && SvTYPE(SvRV(TOPs)) == SVt_PVHV) {
        ob_reg = (HV*)SvRV(POPs);
    }
    PUTBACK;
    FREETMPS;
    LEAVE;

    if (ob_reg)
        return ob_reg;
    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;
91dba0be	23	HV* ob_reg = NULL;
0dbc1c87	24	I32 items;
91dba0be	25	ENTER;
	26	SAVETMPS;
	27
	28	PUSHMARK(SP);
0dbc1c87	29	items = call_pv(HUF_OB_REG, G_SCALAR\|G_NOARGS);
6ff38c27	30	SPAGAIN;
91dba0be	31
	32	if (items == 1 && TOPs && SvROK(TOPs) && SvTYPE(SvRV(TOPs)) == SVt_PVHV) {
	33	ob_reg = (HV*)SvRV(POPs);
6ff38c27	34	}
91dba0be	35	PUTBACK;
	36	FREETMPS;
	37	LEAVE;
	38
	39	if (ob_reg)
	40	return ob_reg;
6ff38c27	41	Perl_die(aTHX_ "Can't get object registry hash");
	42	}
	43
1e73acc8	44	/* Deal with global context */
	45	#define HUF_INIT 1
	46	#define HUF_CLONE 0
	47	#define HUF_RESET -1
	48
	49	void HUF_global(I32 how) {
	50	if (how == HUF_INIT) {
	51	MY_CXT_INIT;
6ff38c27	52	MY_CXT.ob_reg = HUF_get_ob_reg();
1e73acc8	53	} else if (how == HUF_CLONE) {
1e73acc8	54	MY_CXT_CLONE;
6ff38c27	55	MY_CXT.ob_reg = HUF_get_ob_reg();
1e73acc8	56	} else if (how == HUF_RESET) {
1e73acc8	57	dMY_CXT;
6ff38c27	58	MY_CXT.ob_reg = HUF_get_ob_reg();
1e73acc8	59	}
	60	}
	61
	62	/* the id as an SV, optionally marked in the nv (unused feature) */
	63	SV* HUF_id(SV* ref, NV cookie) {
	64	SV* id = sv_newmortal();
	65	if (cookie == 0 ) {
	66	SvUPGRADE(id, SVt_PVIV);
	67	} else {
	68	SvUPGRADE(id, SVt_PVNV);
	69	SvNV_set(id, cookie);
	70	SvNOK_on(id);
	71	}
ce809d1f	72	SvIV_set(id, PTR2UV(SvRV(ref)));
1e73acc8	73	SvIOK_on(id);
	74	return id;
	75	}
	76
	77	/* plain id, only used for field hash entries in field lists */
	78	SV* HUF_field_id(SV* obj) {
	79	return HUF_id(obj, 0.0);
	80	}
	81
6ff38c27	82	/* object id (same as plain, may be different in future) */
1e73acc8	83	SV* HUF_obj_id(SV* obj) {
	84	return HUF_id(obj, 0.0);
	85	}
	86
	87	/* set up uvar magic for any sv */
	88	void HUF_add_uvar_magic(
6ff38c27	89	SV* sv, /* the sv to enchant, visible to get/set */
1e73acc8	90	I32(* val)(pTHX_ IV, SV), / "get" function */
	91	I32(* set)(pTHX_ IV, SV), / "set" function */
	92	I32 index, /* get/set will see this */
	93	SV* thing /* any associated info */
	94	) {
1e73acc8	95	struct ufuncs uf;
	96	uf.uf_val = val;
	97	uf.uf_set = set;
	98	uf.uf_index = index;
	99	sv_magic(sv, thing, PERL_MAGIC_uvar, (char*)&uf, sizeof(uf));
	100	}
	101
	102	/* Fetch the data container of a trigger */
	103	AV* HUF_get_trigger_content(SV* trigger) {
	104	MAGIC* mg;
	105	if (trigger && (mg = mg_find(trigger, PERL_MAGIC_uvar)))
	106	return (AV*)mg->mg_obj;
	107	return NULL;
	108	}
	109
	110	/* Delete an object from all field hashes it may occur in. Also delete
c418a2d4	111	* the object's entry from the object registry. This function goes in
c418a2d4	112	* the uf_set field of the uvar magic of a trigger.
1e73acc8	113	*/
	114	I32 HUF_destroy_obj(pTHX_ IV index, SV* trigger) {
	115	/* Do nothing if the weakref wasn't undef'd. Also don't bother
	116	* during global destruction. (MY_CXT.ob_reg is sometimes funny there) */
	117	if (!SvROK(trigger) && (!PL_in_clean_all)) {
	118	dMY_CXT;
	119	AV* cont = HUF_get_trigger_content(trigger);
	120	SV* ob_id = *av_fetch(cont, 0, 0);
	121	HV* field_tab = (HV) av_fetch(cont, 1, 0);
	122	HE* ent;
	123	hv_iterinit(field_tab);
	124	while (ent = hv_iternext(field_tab)) {
	125	SV* field_ref = HeVAL(ent);
	126	SV* field = SvRV(field_ref);
	127	hv_delete_ent((HV*)field, ob_id, G_DISCARD, 0);
	128	}
	129	/* make it safe in case we must run in global clenaup, after all */
	130	if (PL_in_clean_all)
	131	HUF_global(HUF_RESET);
	132	hv_delete_ent(MY_CXT.ob_reg, ob_id, G_DISCARD, 0);
	133	}
	134	return 0;
	135	}
	136
	137	/* Create a trigger for an object. The trigger is a magical weak ref
	138	* that fires when the weak ref expires. it holds the original id of
	139	* the object, and a list of field hashes from which the object may
	140	* have to be deleted. The trigger is stored in the object registry
	141	* and also deleted when the object expires.
	142	*/
	143	SV* HUF_new_trigger(SV* obj, SV* ob_id) {
	144	dMY_CXT;
	145	SV* trigger = sv_rvweaken(newRV_inc(SvRV(obj)));
	146	AV* cont = newAV();
	147	sv_2mortal((SV*)cont);
	148	av_store(cont, 0, SvREFCNT_inc(ob_id));
	149	av_store(cont, 1, (SV*)newHV());
	150	HUF_add_uvar_magic(trigger, NULL, &HUF_destroy_obj, 0, (SV*)cont);
	151	hv_store_ent(MY_CXT.ob_reg, ob_id, trigger, 0);
	152	return trigger;
	153	}
	154
	155	/* retrieve a trigger for obj if one exists, return NULL otherwise */
	156	SV* HUF_ask_trigger(SV* ob_id) {
	157	dMY_CXT;
	158	HE* ent;
	159	if (ent = hv_fetch_ent(MY_CXT.ob_reg, ob_id, 0, 0))
	160	return HeVAL(ent);
	161	return NULL;
	162	}
	163
	164	/* get the trigger for an object, creating it if necessary */
	165	SV* HUF_get_trigger(SV* obj, SV* ob_id) {
	166	SV* trigger;
	167	if (!(trigger = HUF_ask_trigger(ob_id)))
	168	trigger = HUF_new_trigger(obj, ob_id);
	169	return trigger;
	170	}
	171
	172	/* mark an object (trigger) as having been used with a field */
	173	void HUF_mark_field(SV* trigger, SV* field) {
	174	AV* cont = HUF_get_trigger_content(trigger);
	175	HV* field_tab = (HV) av_fetch(cont, 1, 0);
	176	SV* field_ref = newRV_inc(field);
177	SV* field_id = HUF_field_id(field_ref);
178	hv_store_ent(field_tab, field_id, field_ref, 0);
179	}
180
6ff38c27	181	/* These constants are not in the API. If they ever change in hv.c this code
6ff38c27	182	* must be updated */
a607227a	183	#define HV_FETCH_ISSTORE 0x01
	184	#define HV_FETCH_ISEXISTS 0x02
	185	#define HV_FETCH_LVALUE 0x04
	186	#define HV_FETCH_JUST_SV 0x08
	187
	188	#define HUF_WOULD_CREATE_KEY(x) ((x) != -1 && ((x) & (HV_FETCH_ISSTORE \| HV_FETCH_LVALUE)))
	189
1e73acc8	190	/* The key exchange function. It communicates with S_hv_magic_uvar_xkey
1e73acc8	191	* in hv.c */
1748121c	192	I32 HUF_watch_key(pTHX_ IV action, SV* field) {
1e73acc8	193	MAGIC* mg = mg_find(field, PERL_MAGIC_uvar);
6ff38c27	194	SV* keysv;
	195	if (!mg)
	196	Perl_die(aTHX_ "Rogue call of 'HUF_watch_key'");
	197	keysv = mg->mg_obj;
1e73acc8	198	if (keysv && SvROK(keysv)) {
1e73acc8	199	SV* ob_id = HUF_obj_id(keysv);
1e73acc8	200	mg->mg_obj = ob_id; /* key replacement */
a607227a	201	if (HUF_WOULD_CREATE_KEY(action)) {
	202	SV* trigger = HUF_get_trigger(keysv, ob_id);
	203	HUF_mark_field(trigger, field);
	204	}
1e73acc8	205	}
	206	return 0;
	207	}
	208
	209	/* see if something is a field hash */
	210	int HUF_get_status(HV* hash) {
	211	int ans = 0;
	212	if (hash && (SvTYPE(hash) == SVt_PVHV)) {
1e73acc8	213	MAGIC* mg;
	214	struct ufuncs* uf;
	215	ans = (mg = mg_find((SV*)hash, PERL_MAGIC_uvar)) &&
	216	(uf = (struct ufuncs *)mg->mg_ptr) &&
	217	(uf->uf_val == &HUF_watch_key) &&
	218	(uf->uf_set == NULL);
	219	}
	220	return ans;
	221	}
	222
	223	/* Thread support. These routines are called by CLONE (and nothing else) */
	224
	225	/* Fix entries for one object in all field hashes */
	226	void HUF_fix_trigger(SV* trigger, SV* new_id) {
	227	AV* cont = HUF_get_trigger_content(trigger);
	228	HV* field_tab = (HV) av_fetch(cont, 1, 0);
	229	HV* new_tab = newHV();
	230	HE* ent;
	231	SV* old_id = *av_fetch(cont, 0, 0);
	232	hv_iterinit(field_tab);
	233	while (ent = hv_iternext(field_tab)) {
	234	SV* field_ref = HeVAL(ent);
	235	SV* field_id = HUF_field_id(field_ref);
	236	HV* field = (HV*)SvRV(field_ref);
	237	SV* val;
	238	/* recreate field tab entry */
	239	hv_store_ent(new_tab, field_id, SvREFCNT_inc(field_ref), 0);
	240	/* recreate field entry, if any */
	241	if (val = hv_delete_ent(field, old_id, 0, 0))
	242	hv_store_ent(field, new_id, SvREFCNT_inc(val), 0);
	243	}
	244	/* update the trigger */
	245	av_store(cont, 0, SvREFCNT_inc(new_id));
	246	av_store(cont, 1, (SV*)new_tab);
	247	}
	248
	249	/* Go over object registry and fix all objects. Also fix the object
	250	* registry.
	251	*/
ce809d1f	252	void HUF_fix_objects(void) {
1e73acc8	253	dMY_CXT;
	254	I32 i, len;
	255	HE* ent;
	256	AV* oblist = (AV)sv_2mortal((SV)newAV());
	257	hv_iterinit(MY_CXT.ob_reg);
	258	while(ent = hv_iternext(MY_CXT.ob_reg))
	259	av_push(oblist, SvREFCNT_inc(hv_iterkeysv(ent)));
	260	len = av_len(oblist);
	261	for (i = 0; i <= len; ++i) {
	262	SV* old_id = *av_fetch(oblist, i, 0);
	263	SV* trigger = hv_delete_ent(MY_CXT.ob_reg, old_id, 0, 0);
	264	SV* new_id = HUF_obj_id(trigger);
	265	HUF_fix_trigger(trigger, new_id);
	266	hv_store_ent(MY_CXT.ob_reg, new_id, SvREFCNT_inc(trigger), 0);
	267	}
	268	}
	269
	270	/* test support (not needed for functionality) */
	271
	272	static SV* counter;
1748121c	273	I32 HUF_inc_var(pTHX_ IV index, SV* which) {
1e73acc8	274	sv_setiv(counter, 1 + SvIV(counter));
	275	return 0;
	276	}
	277
	278	MODULE = Hash::Util::FieldHash PACKAGE = Hash::Util::FieldHash
	279
	280	BOOT:
	281	{
	282	HUF_global(HUF_INIT); /* create variables */
	283	}
	284
	285	int
	286	_fieldhash(SV* href, int mode)
	287	PROTOTYPE: $$
	288	CODE:
	289	HV* field;
	290	RETVAL = 0;
	291	if (mode &&
	292	href && SvROK(href) &&
	293	(field = (HV*)SvRV(href)) &&
	294	SvTYPE(field) == SVt_PVHV
	295	) {
	296	HUF_add_uvar_magic(
	297	SvRV(href),
	298	&HUF_watch_key,
	299	NULL,
	300	0,
	301	NULL
	302	);
	303	RETVAL = HUF_get_status(field);
	304	}
	305	OUTPUT:
	306	RETVAL
	307
	308	void
	309	CLONE(char* class)
	310	CODE:
	311	if (0 == strcmp(class, "Hash::Util::FieldHash")) {
	312	HUF_global(HUF_CLONE);
	313	HUF_fix_objects();
	314	}
	315
c418a2d4	316	void
1e73acc8	317	_active_fields(SV* obj)
	318	PPCODE:
	319	if (SvROK(obj)) {
	320	SV* ob_id = HUF_obj_id(obj);
	321	SV* trigger = HUF_ask_trigger(ob_id);
	322	if (trigger) {
	323	AV* cont = HUF_get_trigger_content(trigger);
	324	HV* field_tab = (HV) av_fetch(cont, 1, 0);
	325	HE* ent;
	326	hv_iterinit(field_tab);
	327	while (ent = hv_iternext(field_tab)) {
	328	HV* field = (HV*)SvRV(HeVAL(ent));
	329	if (hv_exists_ent(field, ob_id, 0))
	330	XPUSHs(sv_2mortal(newRV_inc((SV*)field)));
	331	}
	332	}
	333	}
	334
	335	void
	336	_test_uvar_get(SV* svref, SV* countref)
	337	CODE:
	338	if (SvROK(svref) && SvROK(countref)) {
	339	counter = SvRV(countref);
	340	sv_setiv(counter, 0);
	341	HUF_add_uvar_magic(
	342	SvRV(svref),
	343	&HUF_inc_var,
	344	NULL,
	345	0,
	346	SvRV(countref)
	347	);
	348	}
	349
	350	void
	351	_test_uvar_set(SV* svref, SV* countref)
	352	CODE:
	353	if (SvROK(svref) && SvROK(countref)) {
	354	counter = SvRV(countref);
	355	sv_setiv(counter, 0);
	356	counter = SvRV(countref);
	357	HUF_add_uvar_magic(
	358	SvRV(svref),
	359	NULL,
	360	&HUF_inc_var,
	361	0,
	362	SvRV(countref)
	363	);
	364	}
	365
	366	void
	367	_test_uvar_same(SV* svref, SV* countref)
	368	CODE:
	369	if (SvROK(svref) && SvROK(countref)) {
	370	counter = SvRV(countref);
	371	sv_setiv(counter, 0);
	372	HUF_add_uvar_magic(
	373	SvRV(svref),
	374	&HUF_inc_var,
	375	&HUF_inc_var,
	376	0,
	377	NULL
	378	);
	379	}
	380