[perl5.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;
    ENTER;
    SAVETMPS;

    PUSHMARK(SP);
    I32 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 AS	1	#include "EXTERN.h"
	2	#include "perl.h"
	3	#include "XSUB.h"
	4
	5	/* support for Hash::Util::FieldHash, prefix HUF_ */
	6
6ff38c27 AS	7	/* A Perl sub that returns a hashref to the object registry */
6ff38c27 AS	8	#define HUF_OB_REG "Hash::Util::FieldHash::_ob_reg"
1e73acc8 AS	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 AS	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 AS	20	/* Inquire the object registry (a lexical hash) from perl */
	21	HV* HUF_get_ob_reg(void) {
	22	dSP;
91dba0be AS	23	HV* ob_reg = NULL;
	24	ENTER;
	25	SAVETMPS;
	26
	27	PUSHMARK(SP);
6ff38c27 AS	28	I32 items = call_pv(HUF_OB_REG, G_SCALAR\|G_NOARGS);
6ff38c27 AS	29	SPAGAIN;
91dba0be AS	30
	31	if (items == 1 && TOPs && SvROK(TOPs) && SvTYPE(SvRV(TOPs)) == SVt_PVHV) {
	32	ob_reg = (HV*)SvRV(POPs);
6ff38c27	33	}
91dba0be AS	34	PUTBACK;
	35	FREETMPS;
	36	LEAVE;
	37
	38	if (ob_reg)
	39	return ob_reg;
6ff38c27 AS	40	Perl_die(aTHX_ "Can't get object registry hash");
	41	}
	42
1e73acc8 AS	43	/* Deal with global context */
	44	#define HUF_INIT 1
	45	#define HUF_CLONE 0
	46	#define HUF_RESET -1
	47
	48	void HUF_global(I32 how) {
	49	if (how == HUF_INIT) {
	50	MY_CXT_INIT;
6ff38c27	51	MY_CXT.ob_reg = HUF_get_ob_reg();
1e73acc8 AS	52	} else if (how == HUF_CLONE) {
1e73acc8 AS	53	MY_CXT_CLONE;
6ff38c27	54	MY_CXT.ob_reg = HUF_get_ob_reg();
1e73acc8 AS	55	} else if (how == HUF_RESET) {
1e73acc8 AS	56	dMY_CXT;
6ff38c27	57	MY_CXT.ob_reg = HUF_get_ob_reg();
1e73acc8 AS	58	}
	59	}
	60
	61	/* the id as an SV, optionally marked in the nv (unused feature) */
	62	SV* HUF_id(SV* ref, NV cookie) {
	63	SV* id = sv_newmortal();
	64	if (cookie == 0 ) {
	65	SvUPGRADE(id, SVt_PVIV);
	66	} else {
	67	SvUPGRADE(id, SVt_PVNV);
	68	SvNV_set(id, cookie);
	69	SvNOK_on(id);
	70	}
ce809d1f	71	SvIV_set(id, PTR2UV(SvRV(ref)));
1e73acc8 AS	72	SvIOK_on(id);
	73	return id;
	74	}
	75
	76	/* plain id, only used for field hash entries in field lists */
	77	SV* HUF_field_id(SV* obj) {
	78	return HUF_id(obj, 0.0);
	79	}
	80
6ff38c27	81	/* object id (same as plain, may be different in future) */
1e73acc8 AS	82	SV* HUF_obj_id(SV* obj) {
	83	return HUF_id(obj, 0.0);
	84	}
	85
	86	/* set up uvar magic for any sv */
	87	void HUF_add_uvar_magic(
6ff38c27	88	SV* sv, /* the sv to enchant, visible to get/set */
1e73acc8 AS	89	I32(* val)(pTHX_ IV, SV), / "get" function */
	90	I32(* set)(pTHX_ IV, SV), / "set" function */
	91	I32 index, /* get/set will see this */
	92	SV* thing /* any associated info */
	93	) {
1e73acc8 AS	94	struct ufuncs uf;
	95	uf.uf_val = val;
	96	uf.uf_set = set;
	97	uf.uf_index = index;
	98	sv_magic(sv, thing, PERL_MAGIC_uvar, (char*)&uf, sizeof(uf));
	99	}
	100
	101	/* Fetch the data container of a trigger */
	102	AV* HUF_get_trigger_content(SV* trigger) {
	103	MAGIC* mg;
	104	if (trigger && (mg = mg_find(trigger, PERL_MAGIC_uvar)))
	105	return (AV*)mg->mg_obj;
	106	return NULL;
	107	}
	108
	109	/* Delete an object from all field hashes it may occur in. Also delete
c418a2d4 AS	110	* the object's entry from the object registry. This function goes in
c418a2d4 AS	111	* the uf_set field of the uvar magic of a trigger.
1e73acc8 AS	112	*/
	113	I32 HUF_destroy_obj(pTHX_ IV index, SV* trigger) {
	114	/* Do nothing if the weakref wasn't undef'd. Also don't bother
	115	* during global destruction. (MY_CXT.ob_reg is sometimes funny there) */
	116	if (!SvROK(trigger) && (!PL_in_clean_all)) {
	117	dMY_CXT;
	118	AV* cont = HUF_get_trigger_content(trigger);
	119	SV* ob_id = *av_fetch(cont, 0, 0);
	120	HV* field_tab = (HV) av_fetch(cont, 1, 0);
	121	HE* ent;
	122	hv_iterinit(field_tab);
	123	while (ent = hv_iternext(field_tab)) {
	124	SV* field_ref = HeVAL(ent);
	125	SV* field = SvRV(field_ref);
	126	hv_delete_ent((HV*)field, ob_id, G_DISCARD, 0);
	127	}
	128	/* make it safe in case we must run in global clenaup, after all */
	129	if (PL_in_clean_all)
	130	HUF_global(HUF_RESET);
	131	hv_delete_ent(MY_CXT.ob_reg, ob_id, G_DISCARD, 0);
	132	}
	133	return 0;
	134	}
	135
	136	/* Create a trigger for an object. The trigger is a magical weak ref
	137	* that fires when the weak ref expires. it holds the original id of
	138	* the object, and a list of field hashes from which the object may
	139	* have to be deleted. The trigger is stored in the object registry
	140	* and also deleted when the object expires.
	141	*/
	142	SV* HUF_new_trigger(SV* obj, SV* ob_id) {
	143	dMY_CXT;
	144	SV* trigger = sv_rvweaken(newRV_inc(SvRV(obj)));
	145	AV* cont = newAV();
	146	sv_2mortal((SV*)cont);
	147	av_store(cont, 0, SvREFCNT_inc(ob_id));
	148	av_store(cont, 1, (SV*)newHV());
	149	HUF_add_uvar_magic(trigger, NULL, &HUF_destroy_obj, 0, (SV*)cont);
	150	hv_store_ent(MY_CXT.ob_reg, ob_id, trigger, 0);
	151	return trigger;
	152	}
	153
	154	/* retrieve a trigger for obj if one exists, return NULL otherwise */
	155	SV* HUF_ask_trigger(SV* ob_id) {
	156	dMY_CXT;
	157	HE* ent;
	158	if (ent = hv_fetch_ent(MY_CXT.ob_reg, ob_id, 0, 0))
	159	return HeVAL(ent);
	160	return NULL;
	161	}
	162
	163	/* get the trigger for an object, creating it if necessary */
	164	SV* HUF_get_trigger(SV* obj, SV* ob_id) {
	165	SV* trigger;
	166	if (!(trigger = HUF_ask_trigger(ob_id)))
	167	trigger = HUF_new_trigger(obj, ob_id);
	168	return trigger;
	169	}
	170
	171	/* mark an object (trigger) as having been used with a field */
	172	void HUF_mark_field(SV* trigger, SV* field) {
	173	AV* cont = HUF_get_trigger_content(trigger);
	174	HV* field_tab = (HV) av_fetch(cont, 1, 0);
	175	SV* field_ref = newRV_inc(field);
176	SV* field_id = HUF_field_id(field_ref);
177	hv_store_ent(field_tab, field_id, field_ref, 0);
178	}
179
6ff38c27 AS	180	/* These constants are not in the API. If they ever change in hv.c this code
6ff38c27 AS	181	* must be updated */
a607227a AS	182	#define HV_FETCH_ISSTORE 0x01
	183	#define HV_FETCH_ISEXISTS 0x02
	184	#define HV_FETCH_LVALUE 0x04
	185	#define HV_FETCH_JUST_SV 0x08
	186
	187	#define HUF_WOULD_CREATE_KEY(x) ((x) != -1 && ((x) & (HV_FETCH_ISSTORE \| HV_FETCH_LVALUE)))
	188
1e73acc8 AS	189	/* The key exchange function. It communicates with S_hv_magic_uvar_xkey
1e73acc8 AS	190	* in hv.c */
1748121c	191	I32 HUF_watch_key(pTHX_ IV action, SV* field) {
1e73acc8	192	MAGIC* mg = mg_find(field, PERL_MAGIC_uvar);
6ff38c27 AS	193	SV* keysv;
	194	if (!mg)
	195	Perl_die(aTHX_ "Rogue call of 'HUF_watch_key'");
	196	keysv = mg->mg_obj;
1e73acc8 AS	197	if (keysv && SvROK(keysv)) {
1e73acc8 AS	198	SV* ob_id = HUF_obj_id(keysv);
1e73acc8	199	mg->mg_obj = ob_id; /* key replacement */
a607227a AS	200	if (HUF_WOULD_CREATE_KEY(action)) {
	201	SV* trigger = HUF_get_trigger(keysv, ob_id);
	202	HUF_mark_field(trigger, field);
	203	}
1e73acc8 AS	204	}
	205	return 0;
	206	}
	207
	208	/* see if something is a field hash */
	209	int HUF_get_status(HV* hash) {
	210	int ans = 0;
	211	if (hash && (SvTYPE(hash) == SVt_PVHV)) {
1e73acc8 AS	212	MAGIC* mg;
	213	struct ufuncs* uf;
	214	ans = (mg = mg_find((SV*)hash, PERL_MAGIC_uvar)) &&
	215	(uf = (struct ufuncs *)mg->mg_ptr) &&
	216	(uf->uf_val == &HUF_watch_key) &&
	217	(uf->uf_set == NULL);
	218	}
	219	return ans;
	220	}
	221
	222	/* Thread support. These routines are called by CLONE (and nothing else) */
	223
	224	/* Fix entries for one object in all field hashes */
	225	void HUF_fix_trigger(SV* trigger, SV* new_id) {
	226	AV* cont = HUF_get_trigger_content(trigger);
	227	HV* field_tab = (HV) av_fetch(cont, 1, 0);
	228	HV* new_tab = newHV();
	229	HE* ent;
	230	SV* old_id = *av_fetch(cont, 0, 0);
	231	hv_iterinit(field_tab);
	232	while (ent = hv_iternext(field_tab)) {
	233	SV* field_ref = HeVAL(ent);
	234	SV* field_id = HUF_field_id(field_ref);
	235	HV* field = (HV*)SvRV(field_ref);
	236	SV* val;
	237	/* recreate field tab entry */
	238	hv_store_ent(new_tab, field_id, SvREFCNT_inc(field_ref), 0);
	239	/* recreate field entry, if any */
	240	if (val = hv_delete_ent(field, old_id, 0, 0))
	241	hv_store_ent(field, new_id, SvREFCNT_inc(val), 0);
	242	}
	243	/* update the trigger */
	244	av_store(cont, 0, SvREFCNT_inc(new_id));
	245	av_store(cont, 1, (SV*)new_tab);
	246	}
	247
	248	/* Go over object registry and fix all objects. Also fix the object
	249	* registry.
	250	*/
ce809d1f	251	void HUF_fix_objects(void) {
1e73acc8 AS	252	dMY_CXT;
	253	I32 i, len;
	254	HE* ent;
	255	AV* oblist = (AV)sv_2mortal((SV)newAV());
	256	hv_iterinit(MY_CXT.ob_reg);
	257	while(ent = hv_iternext(MY_CXT.ob_reg))
	258	av_push(oblist, SvREFCNT_inc(hv_iterkeysv(ent)));
	259	len = av_len(oblist);
	260	for (i = 0; i <= len; ++i) {
	261	SV* old_id = *av_fetch(oblist, i, 0);
	262	SV* trigger = hv_delete_ent(MY_CXT.ob_reg, old_id, 0, 0);
	263	SV* new_id = HUF_obj_id(trigger);
	264	HUF_fix_trigger(trigger, new_id);
	265	hv_store_ent(MY_CXT.ob_reg, new_id, SvREFCNT_inc(trigger), 0);
	266	}
	267	}
	268
	269	/* test support (not needed for functionality) */
	270
	271	static SV* counter;
1748121c	272	I32 HUF_inc_var(pTHX_ IV index, SV* which) {
1e73acc8 AS	273	sv_setiv(counter, 1 + SvIV(counter));
	274	return 0;
	275	}
	276
	277	MODULE = Hash::Util::FieldHash PACKAGE = Hash::Util::FieldHash
	278
	279	BOOT:
	280	{
	281	HUF_global(HUF_INIT); /* create variables */
	282	}
	283
	284	int
	285	_fieldhash(SV* href, int mode)
	286	PROTOTYPE: $$
	287	CODE:
	288	HV* field;
	289	RETVAL = 0;
	290	if (mode &&
	291	href && SvROK(href) &&
	292	(field = (HV*)SvRV(href)) &&
	293	SvTYPE(field) == SVt_PVHV
	294	) {
	295	HUF_add_uvar_magic(
	296	SvRV(href),
	297	&HUF_watch_key,
	298	NULL,
	299	0,
	300	NULL
	301	);
	302	RETVAL = HUF_get_status(field);
	303	}
	304	OUTPUT:
	305	RETVAL
	306
	307	void
	308	CLONE(char* class)
	309	CODE:
	310	if (0 == strcmp(class, "Hash::Util::FieldHash")) {
	311	HUF_global(HUF_CLONE);
	312	HUF_fix_objects();
	313	}
	314
c418a2d4	315	void
1e73acc8 AS	316	_active_fields(SV* obj)
	317	PPCODE:
	318	if (SvROK(obj)) {
	319	SV* ob_id = HUF_obj_id(obj);
	320	SV* trigger = HUF_ask_trigger(ob_id);
	321	if (trigger) {
	322	AV* cont = HUF_get_trigger_content(trigger);
	323	HV* field_tab = (HV) av_fetch(cont, 1, 0);
	324	HE* ent;
	325	hv_iterinit(field_tab);
	326	while (ent = hv_iternext(field_tab)) {
	327	HV* field = (HV*)SvRV(HeVAL(ent));
	328	if (hv_exists_ent(field, ob_id, 0))
	329	XPUSHs(sv_2mortal(newRV_inc((SV*)field)));
	330	}
	331	}
	332	}
	333
	334	void
	335	_test_uvar_get(SV* svref, SV* countref)
	336	CODE:
	337	if (SvROK(svref) && SvROK(countref)) {
	338	counter = SvRV(countref);
	339	sv_setiv(counter, 0);
	340	HUF_add_uvar_magic(
	341	SvRV(svref),
	342	&HUF_inc_var,
	343	NULL,
	344	0,
	345	SvRV(countref)
	346	);
	347	}
	348
	349	void
	350	_test_uvar_set(SV* svref, SV* countref)
	351	CODE:
	352	if (SvROK(svref) && SvROK(countref)) {
	353	counter = SvRV(countref);
	354	sv_setiv(counter, 0);
	355	counter = SvRV(countref);
	356	HUF_add_uvar_magic(
	357	SvRV(svref),
	358	NULL,
	359	&HUF_inc_var,
	360	0,
	361	SvRV(countref)
	362	);
	363	}
	364
	365	void
	366	_test_uvar_same(SV* svref, SV* countref)
	367	CODE:
	368	if (SvROK(svref) && SvROK(countref)) {
	369	counter = SvRV(countref);
	370	sv_setiv(counter, 0);
	371	HUF_add_uvar_magic(
	372	SvRV(svref),
	373	&HUF_inc_var,
	374	&HUF_inc_var,
	375	0,
	376	NULL
	377	);
	378	}
	379