Add xs accessors

[gitmo/Class-MOP.git] / mop.c

#include "mop.h"

void
mop_call_xs (pTHX_ XSPROTO(subaddr), CV *cv, SV **mark)
{
    dSP;
    PUSHMARK(mark);
    (*subaddr)(aTHX_ cv);
    PUTBACK;
}

#if PERL_BCDVERSION >= 0x5010000
UV
mop_check_package_cache_flag (pTHX_ HV *stash)
{
    assert(SvTYPE(stash) == SVt_PVHV);

    /* here we're trying to implement a c version of mro::get_pkg_gen($stash),
     * however the perl core doesn't make it easy for us. It doesn't provide an
     * api that just does what we want.
     *
     * However, we know that the information we want is, inside the core,
     * available using HvMROMETA(stash)->pkg_gen. Unfortunately, although the
     * HvMROMETA macro is public, it is implemented using Perl_mro_meta_init,
     * which is not public and only available inside the core, as the mro
     * interface as well as the structure returned by mro_meta_init isn't
     * considered to be stable yet.
     *
     * Perl_mro_meta_init isn't declared static, so we could just define it
     * ourselfs if perls headers don't do that for us, except that won't work
     * on platforms where symbols need to be explicitly exported when linking
     * shared libraries.
     *
     * So our, hopefully temporary, solution is to be even more evil and
     * basically reimplement HvMROMETA in a very fragile way that'll blow up
     * when the relevant parts of the mro implementation in core change.
     *
     * :-(
     *
     */

    return HvAUX(stash)->xhv_mro_meta
         ? HvAUX(stash)->xhv_mro_meta->pkg_gen
         : 0;
}

#else /* pre 5.10.0 */

UV
mop_check_package_cache_flag (pTHX_ HV *stash)
{
    PERL_UNUSED_ARG(stash);
    assert(SvTYPE(stash) == SVt_PVHV);

    return PL_sub_generation;
}
#endif

SV *
mop_call0 (pTHX_ SV *const self, SV *const method)
{
    dSP;
    SV *ret;

    PUSHMARK(SP);
    XPUSHs(self);
    PUTBACK;

    call_sv(method, G_SCALAR | G_METHOD);

    SPAGAIN;
    ret = POPs;
    PUTBACK;

    return ret;
}

int
mop_get_code_info (SV *coderef, char **pkg, char **name)
{
    if (!SvOK(coderef) || !SvROK(coderef) || SvTYPE(SvRV(coderef)) != SVt_PVCV) {
        return 0;
    }

    coderef = SvRV(coderef);

    /* sub is still being compiled */
    if (!CvGV(coderef)) {
        return 0;
    }

    /* I think this only gets triggered with a mangled coderef, but if
       we hit it without the guard, we segfault. The slightly odd return
       value strikes me as an improvement (mst)
    */

    if ( isGV_with_GP(CvGV(coderef)) ) {
        GV *gv   = CvGV(coderef);
        *pkg     = HvNAME( GvSTASH(gv) ? GvSTASH(gv) : CvSTASH(coderef) );
        *name    = GvNAME( CvGV(coderef) );
    } else {
        *pkg     = "__UNKNOWN__";
        *name    = "__ANON__";
    }

    return 1;
}

void
mop_get_package_symbols (HV *stash, type_filter_t filter, get_package_symbols_cb_t cb, void *ud)
{
    HE *he;

    (void)hv_iterinit(stash);

    if (filter == TYPE_FILTER_NONE) {
        while ( (he = hv_iternext(stash)) ) {
            STRLEN keylen;
            const char *key = HePV(he, keylen);
            if (!cb(key, keylen, HeVAL(he), ud)) {
                return;
            }
        }
        return;
    }

    while ( (he = hv_iternext(stash)) ) {
        GV * const gv          = (GV*)HeVAL(he);
        STRLEN keylen;
        const char * const key = HePV(he, keylen);
        SV *sv = NULL;

        if(isGV(gv)){
            switch (filter) {
                case TYPE_FILTER_CODE:   sv = (SV *)GvCVu(gv); break;
                case TYPE_FILTER_ARRAY:  sv = (SV *)GvAV(gv);  break;
                case TYPE_FILTER_IO:     sv = (SV *)GvIO(gv);  break;
                case TYPE_FILTER_HASH:   sv = (SV *)GvHV(gv);  break;
                case TYPE_FILTER_SCALAR: sv = (SV *)GvSV(gv);  break;
                default:
                    croak("Unknown type");
            }
        }
        /* expand the gv into a real typeglob if it
        * contains stub functions or constants and we
        * were asked to return CODE references */
        else if (filter == TYPE_FILTER_CODE) {
            gv_init(gv, stash, key, keylen, GV_ADDMULTI);
            sv = (SV *)GvCV(gv);
        }

        if (sv) {
            if (!cb(key, keylen, sv, ud)) {
                return;
            }
        }
    }
}

static bool
collect_all_symbols (const char *key, STRLEN keylen, SV *val, void *ud)
{
    HV *hash = (HV *)ud;

    if (!hv_store (hash, key, keylen, newRV_inc(val), 0)) {
        croak("failed to store symbol ref");
    }

    return TRUE;
}

HV *
mop_get_all_package_symbols (HV *stash, type_filter_t filter)
{
    HV *ret = newHV ();
    mop_get_package_symbols (stash, filter, collect_all_symbols, ret);
    return ret;
}

static MGVTBL mop_accessor_vtbl; /* the MAGIC identity */

CV*
mop_install_simple_accessor(pTHX_ const char* const fq_name, const char* const key, I32 const keylen, XSPROTO(accessor_impl)){
    CV* const xsub  = newXS((char*)fq_name, accessor_impl, __FILE__);
    SV* const keysv = newSVpvn_share(key, keylen, 0U);

    sv_magicext((SV*)xsub, keysv, PERL_MAGIC_ext, &mop_accessor_vtbl, NULL, 0);
    SvREFCNT_dec(keysv); /* sv_magicext() increases refcnt in mg_obj */
    return xsub;
}

static MAGIC*
mop_mg_find_by_vtbl(pTHX_ SV* const sv, const MGVTBL* const vtbl){
    MAGIC* mg;

    assert(sv != NULL);
    for(mg = SvMAGIC(sv); mg; mg = mg->mg_moremagic){
        if(mg->mg_virtual == vtbl){
            break;
        }
    }
    return mg;
}

static SV*
mop_fetch_attr(pTHX_ SV* const self, SV* const key, I32 const create, CV* const cv){
    HE* he;
    if (!SvROK(self)) {
        croak("can't call %s as a class method", GvNAME(CvGV(cv)));
    }
    if (SvTYPE(SvRV(self)) != SVt_PVHV) {
        croak("object is not a hashref");
    }
    if((he = hv_fetch_ent((HV*)SvRV(self), key, create, 0U))){
        return HeVAL(he);
    }
    return NULL;
}
static SV*
mop_delete_attr(pTHX_ SV* const self, SV* const key, CV* const cv){
    SV* sv;
    if (!SvROK(self)) {
        croak("can't call %s as a class method", GvNAME(CvGV(cv)));
    }
    if (SvTYPE(SvRV(self)) != SVt_PVHV) {
        croak("object is not a hashref");
    }
    if((sv = hv_delete_ent((HV*)SvRV(self), key, 0, 0U))){
        return sv;
    }
    return NULL;
}

XS(mop_xs_simple_accessor)
{
    dVAR; dXSARGS;
    MAGIC* const mg = mop_mg_find_by_vtbl(aTHX_ (SV*)cv, &mop_accessor_vtbl);
    SV* const key   = mg->mg_obj;
    SV* attr;
    if(items == 1){ /* reader */
        attr = mop_fetch_attr(aTHX_ ST(0), key, FALSE, cv);
    }
    else if (items == 2){ /* writer */
        attr = mop_fetch_attr(aTHX_ ST(0), key, TRUE, cv);
        sv_setsv(attr, ST(1));
    }
    else{
        croak("expected exactly one or two argument");
    }
    ST(0) = attr ? attr : &PL_sv_undef;
    XSRETURN(1);
}


XS(mop_xs_simple_reader)
{
    dVAR; dXSARGS;
    MAGIC* const mg = mop_mg_find_by_vtbl(aTHX_ (SV*)cv, &mop_accessor_vtbl);
    SV* const key   = mg->mg_obj;
    SV* attr;

    if (items != 1) {
        croak("expected exactly one argument");
    }

    attr = mop_fetch_attr(aTHX_ ST(0), key, FALSE, cv);
    ST(0) = attr ? attr : &PL_sv_undef;
    XSRETURN(1);
}

XS(mop_xs_simple_writer)
{
    dVAR; dXSARGS;
    MAGIC* const mg = mop_mg_find_by_vtbl(aTHX_ (SV*)cv, &mop_accessor_vtbl);
    SV* const key   = mg->mg_obj;
    SV* attr;

    if (items != 2) {
        croak("expected exactly two argument");
    }

    attr = mop_fetch_attr(aTHX_ ST(0), key, TRUE, cv);
    sv_setsv(attr, ST(1));
    ST(0) = attr;
    XSRETURN(1);
}

XS(mop_xs_simple_clearer)
{
    dVAR; dXSARGS;
    MAGIC* const mg = mop_mg_find_by_vtbl(aTHX_ (SV*)cv, &mop_accessor_vtbl);
    SV* const key   = mg->mg_obj;
    SV* attr;

    if (items != 1) {
        croak("expected exactly one argument");
    }

    attr = mop_delete_attr(aTHX_ ST(0), key, cv);
    ST(0) = attr ? attr : &PL_sv_undef;
    XSRETURN(1);
}


XS(mop_xs_simple_predicate)
{
    dVAR; dXSARGS;
    MAGIC* const mg = mop_mg_find_by_vtbl(aTHX_ (SV*)cv, &mop_accessor_vtbl);
    SV* const key   = mg->mg_obj;
    SV* attr;

    if (items != 1) {
        croak("expected exactly one argument");
    }

    attr = mop_fetch_attr(aTHX_ ST(0), key, FALSE, cv);
    ST(0) = boolSV(attr); /* exists */
    XSRETURN(1);
}


XS(mop_xs_simple_predicate_for_metaclass)
{
    dVAR; dXSARGS;
    MAGIC* const mg = mop_mg_find_by_vtbl(aTHX_ (SV*)cv, &mop_accessor_vtbl);
    SV* const key   = mg->mg_obj;
    SV* attr;

    if (items != 1) {
        croak("expected exactly one argument");
    }

    attr = mop_fetch_attr(aTHX_ ST(0), key, FALSE, cv);
    ST(0) = boolSV(attr && SvOK(attr)); /* defined */
    XSRETURN(1);
}