#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)
Perl_die(aTHX_ "Can't get object registry hash");
return ob_reg;
}
/* 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) {
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);
}
}
} else {
Perl_die(aTHX_ "Rogue call of 'HUF_watch_key'");
}
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
);
}