X-Git-Url: https://perl5.git.perl.org/perl5.git/blobdiff_plain/4aa3a86749acdb989cb33981ae3dd1fde939b66a..ee872193302939c724fd6c2c18071c621bfac6c4:/hv.c diff --git a/hv.c b/hv.c index d0f452e..8b186de 100644 --- a/hv.c +++ b/hv.c @@ -604,21 +604,18 @@ Perl_hv_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen, } } - if (HvREHASH(hv)) { - PERL_HASH_INTERNAL(hash, key, klen); - /* We don't have a pointer to the hv, so we have to replicate the - flag into every HEK, so that hv_iterkeysv can see it. */ - /* And yes, you do need this even though you are not "storing" because - you can flip the flags below if doing an lval lookup. (And that - was put in to give the semantics Andreas was expecting.) */ + if (HvREHASH(hv) || (!hash && !(keysv && (SvIsCOW_shared_hash(keysv))))) + PERL_HASH_INTERNAL_(hash, key, klen, HvREHASH(hv)); + else if (!hash) + hash = SvSHARED_HASH(keysv); + + /* We don't have a pointer to the hv, so we have to replicate the + flag into every HEK, so that hv_iterkeysv can see it. + And yes, you do need this even though you are not "storing" because + you can flip the flags below if doing an lval lookup. (And that + was put in to give the semantics Andreas was expecting.) */ + if (HvREHASH(hv)) flags |= HVhek_REHASH; - } else if (!hash) { - if (keysv && (SvIsCOW_shared_hash(keysv))) { - hash = SvSHARED_HASH(keysv); - } else { - PERL_HASH(hash, key, klen); - } - } masked_flags = (flags & HVhek_MASK); @@ -682,7 +679,7 @@ Perl_hv_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen, much back at this point (in hv_store's code). */ break; } - /* LVAL fetch which actaully needs a store. */ + /* LVAL fetch which actually needs a store. */ val = newSV(0); HvPLACEHOLDERS(hv)--; } else { @@ -800,6 +797,12 @@ Perl_hv_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen, xhv->xhv_keys++; /* HvTOTALKEYS(hv)++ */ if (!counter) { /* initial entry? */ } else if (xhv->xhv_keys > xhv->xhv_max) { + /* Use only the old HvUSEDKEYS(hv) > HvMAX(hv) condition to limit + bucket splits on a rehashed hash, as we're not going to + split it again, and if someone is lucky (evil) enough to + get all the keys in one list they could exhaust our memory + as we repeatedly double the number of buckets on every + entry. Linear search feels a less worse thing to do. */ hsplit(hv); } else if(!HvREHASH(hv)) { U32 n_links = 1; @@ -808,12 +811,6 @@ Perl_hv_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen, n_links++; if (n_links > HV_MAX_LENGTH_BEFORE_SPLIT) { - /* Use only the old HvKEYS(hv) > HvMAX(hv) condition to limit - bucket splits on a rehashed hash, as we're not going to - split it again, and if someone is lucky (evil) enough to - get all the keys in one list they could exhaust our memory - as we repeatedly double the number of buckets on every - entry. Linear search feels a less worse thing to do. */ hsplit(hv); } } @@ -904,7 +901,6 @@ S_hv_delete_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen, register XPVHV* xhv; register HE *entry; register HE **oentry; - HE *const *first_entry; bool is_utf8 = (k_flags & HVhek_UTF8) ? TRUE : FALSE; int masked_flags; @@ -971,19 +967,14 @@ S_hv_delete_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen, HvHASKFLAGS_on(MUTABLE_SV(hv)); } - if (HvREHASH(hv)) { - PERL_HASH_INTERNAL(hash, key, klen); - } else if (!hash) { - if (keysv && (SvIsCOW_shared_hash(keysv))) { - hash = SvSHARED_HASH(keysv); - } else { - PERL_HASH(hash, key, klen); - } - } + if (HvREHASH(hv) || (!hash && !(keysv && (SvIsCOW_shared_hash(keysv))))) + PERL_HASH_INTERNAL_(hash, key, klen, HvREHASH(hv)); + else if (!hash) + hash = SvSHARED_HASH(keysv); masked_flags = (k_flags & HVhek_MASK); - first_entry = oentry = &(HvARRAY(hv))[hash & (I32) HvMAX(hv)]; + oentry = &(HvARRAY(hv))[hash & (I32) HvMAX(hv)]; entry = *oentry; for (; entry; oentry = &HeNEXT(entry), entry = *oentry) { SV *sv; @@ -1026,7 +1017,11 @@ S_hv_delete_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen, if (HeVAL(entry) && HvENAME_get(hv)) { gv = (GV *)HeVAL(entry); if (keysv) key = SvPV(keysv, klen); - if (klen > 1 && key[klen-2] == ':' && key[klen-1] == ':' + if (( + (klen > 1 && key[klen-2] == ':' && key[klen-1] == ':') + || + (klen == 1 && key[0] == ':') + ) && (klen != 6 || hv!=PL_defstash || memNE(key,"main::",6)) && SvTYPE(gv) == SVt_PVGV && (stash = GvHV((GV *)gv)) && HvENAME_get(stash)) { @@ -1475,7 +1470,6 @@ Perl_hv_free_ent(pTHX_ HV *hv, register HE *entry) val = HeVAL(entry); if (val && isGV(val) && isGV_with_GP(val) && GvCVu(val) && HvENAME(hv)) mro_method_changed_in(hv); /* deletion of method from stash */ - SvREFCNT_dec(val); if (HeKLEN(entry) == HEf_SVKEY) { SvREFCNT_dec(HeKEY_sv(entry)); Safefree(HeKEY_hek(entry)); @@ -1485,6 +1479,7 @@ Perl_hv_free_ent(pTHX_ HV *hv, register HE *entry) else Safefree(HeKEY_hek(entry)); del_HE(entry); + SvREFCNT_dec(val); } @@ -1545,20 +1540,17 @@ Perl_hv_clear(pTHX_ HV *hv) } } } - goto reset; } + else { + hfreeentries(hv); + HvPLACEHOLDERS_set(hv, 0); - hfreeentries(hv); - HvPLACEHOLDERS_set(hv, 0); - if (HvARRAY(hv)) - Zero(HvARRAY(hv), xhv->xhv_max+1 /* HvMAX(hv)+1 */, HE*); - - if (SvRMAGICAL(hv)) - mg_clear(MUTABLE_SV(hv)); + if (SvRMAGICAL(hv)) + mg_clear(MUTABLE_SV(hv)); - HvHASKFLAGS_off(hv); - HvREHASH_off(hv); - reset: + HvHASKFLAGS_off(hv); + HvREHASH_off(hv); + } if (SvOOK(hv)) { if(HvENAME_get(hv)) mro_isa_changed_in(hv); @@ -1606,7 +1598,6 @@ S_clear_placeholders(pTHX_ HV *hv, U32 items) i = HvMAX(hv); do { /* Loop down the linked list heads */ - bool first = TRUE; HE **oentry = &(HvARRAY(hv))[i]; HE *entry; @@ -1621,14 +1612,13 @@ S_clear_placeholders(pTHX_ HV *hv, U32 items) if (--items == 0) { /* Finished. */ HvTOTALKEYS(hv) -= (IV)HvPLACEHOLDERS_get(hv); - if (HvKEYS(hv) == 0) + if (HvUSEDKEYS(hv) == 0) HvHASKFLAGS_off(hv); HvPLACEHOLDERS_set(hv, 0); return; } } else { oentry = &HeNEXT(entry); - first = FALSE; } } } while (--i >= 0); @@ -1640,205 +1630,67 @@ S_clear_placeholders(pTHX_ HV *hv, U32 items) STATIC void S_hfreeentries(pTHX_ HV *hv) { - /* This is the array that we're going to restore */ - HE **const orig_array = HvARRAY(hv); - HE **tmp_array = NULL; - const bool has_aux = SvOOK(hv); - struct xpvhv_aux * current_aux = NULL; - int attempts = 100; - + STRLEN i = 0; const bool mpm = PL_phase != PERL_PHASE_DESTRUCT && HvENAME(hv); PERL_ARGS_ASSERT_HFREEENTRIES; - if (!orig_array) + if (!HvARRAY(hv)) return; - /* orig_array remains unchanged throughout the loop. If after freeing all - the entries it turns out that one of the little blighters has triggered - an action that has caused HvARRAY to be re-allocated, then we set - array to the new HvARRAY, and try again. */ - - while (1) { - /* This is the one we're going to try to empty. First time round - it's the original array. (Hopefully there will only be 1 time - round) */ - HE ** const array = HvARRAY(hv); - I32 i = HvMAX(hv); - - struct xpvhv_aux *iter = SvOOK(hv) ? HvAUX(hv) : NULL; - - /* If there are no keys, we only need to free items in the aux - structure and then exit the loop. */ - const bool empty = !((XPVHV*) SvANY(hv))->xhv_keys; - - /* make everyone else think the array is empty, so that the destructors - * called for freed entries can't recursively mess with us */ - if (!empty) HvARRAY(hv) = NULL; - - if (SvOOK(hv)) { - HE *entry; - - if (!empty) { - SvFLAGS(hv) &= ~SVf_OOK; /* Goodbye, aux structure. */ - /* What aux structure? */ - /* (But we still have a pointer to it in iter.) */ - - /* Copy the name and MRO stuff to a new aux structure - if present. */ - if (iter->xhv_name_u.xhvnameu_name || iter->xhv_mro_meta) { - struct xpvhv_aux * const newaux = hv_auxinit(hv); - newaux->xhv_name_count = iter->xhv_name_count; - if (newaux->xhv_name_count) - newaux->xhv_name_u.xhvnameu_names - = iter->xhv_name_u.xhvnameu_names; - else - newaux->xhv_name_u.xhvnameu_name - = iter->xhv_name_u.xhvnameu_name; - - iter->xhv_name_u.xhvnameu_name = NULL; - newaux->xhv_mro_meta = iter->xhv_mro_meta; - iter->xhv_mro_meta = NULL; - } - - /* Because we have taken xhv_name and xhv_mro_meta out, the - only allocated pointers in the aux structure that might - exist are the back-reference array and xhv_eiter. - */ - } - - /* weak references: if called from sv_clear(), the backrefs - * should already have been killed; if there are any left, its - * because we're doing hv_clear() or hv_undef(), and the HV - * will continue to live. - * Because while freeing the entries we fake up a NULL HvARRAY - * (and hence HvAUX), we need to store the backref array - * somewhere else; but it still needs to be visible in case - * any the things we free happen to call sv_del_backref(). - * We do this by storing it in magic instead. - * If, during the entry freeing, a destructor happens to add - * a new weak backref, then sv_add_backref will look in both - * places (magic in HvAUX) for the AV, but will create a new - * AV in HvAUX if it can't find one (if it finds it in magic, - * it moves it back into HvAUX. So at the end of the iteration - * we have to allow for this. */ - - - if (iter->xhv_backreferences) { - if (SvTYPE(iter->xhv_backreferences) == SVt_PVAV) { - /* The sv_magic will increase the reference count of the AV, - so we need to drop it first. */ - SvREFCNT_dec(iter->xhv_backreferences); - if (AvFILLp(iter->xhv_backreferences) == -1) { - /* Turns out that the array is empty. Just free it. */ - SvREFCNT_dec(iter->xhv_backreferences); + /* keep looping until all keys are removed. This may take multiple + * passes through the array, since destructors may add things back. */ - } else { - sv_magic(MUTABLE_SV(hv), - MUTABLE_SV(iter->xhv_backreferences), - PERL_MAGIC_backref, NULL, 0); - } - } - else { - MAGIC *mg; - sv_magic(MUTABLE_SV(hv), NULL, PERL_MAGIC_backref, NULL, 0); - mg = mg_find(MUTABLE_SV(hv), PERL_MAGIC_backref); - mg->mg_obj = (SV*)iter->xhv_backreferences; - } - iter->xhv_backreferences = NULL; - } + while (((XPVHV*)SvANY(hv))->xhv_keys) { + struct xpvhv_aux *iter; + HE *entry; + HE ** array; - entry = iter->xhv_eiter; /* HvEITER(hv) */ + if (SvOOK(hv) && ((iter = HvAUX(hv))) + && ((entry = iter->xhv_eiter)) ) + { + /* the iterator may get resurrected after each + * destructor call, so check each time */ if (entry && HvLAZYDEL(hv)) { /* was deleted earlier? */ HvLAZYDEL_off(hv); hv_free_ent(hv, entry); + /* warning: at this point HvARRAY may have been + * re-allocated, HvMAX changed etc */ } iter->xhv_riter = -1; /* HvRITER(hv) = -1 */ iter->xhv_eiter = NULL; /* HvEITER(hv) = NULL */ - - /* There are now no allocated pointers in the aux structure - unless the hash is empty. */ } - /* If there are no keys, there is nothing left to free. */ - if (empty) break; - - /* Since we have removed the HvARRAY (and possibly replaced it by - calling hv_auxinit), set the number of keys accordingly. */ - ((XPVHV*) SvANY(hv))->xhv_keys = 0; - - do { - /* Loop down the linked list heads */ - HE *entry = array[i]; - - while (entry) { - register HE * const oentry = entry; - entry = HeNEXT(entry); - if ( - mpm && HeVAL(oentry) && isGV(HeVAL(oentry)) && - GvHV(HeVAL(oentry)) && HvENAME(GvHV(HeVAL(oentry))) - ) { - STRLEN klen; - const char * const key = HePV(oentry,klen); - if (klen > 1 && key[klen-1]==':' && key[klen-2]==':') { - mro_package_moved( - NULL, GvHV(HeVAL(oentry)), - (GV *)HeVAL(oentry), 0 - ); - } + array = HvARRAY(hv); + entry = array[i]; + if (entry) { + /* Detach and free this entry. Note that destructors may be + * called which will manipulate this hash, so make sure + * its internal structure remains consistent throughout */ + array[i] = HeNEXT(entry); + ((XPVHV*) SvANY(hv))->xhv_keys--; + + if ( mpm && HeVAL(entry) && isGV(HeVAL(entry)) + && GvHV(HeVAL(entry)) && HvENAME(GvHV(HeVAL(entry))) + ) { + STRLEN klen; + const char * const key = HePV(entry,klen); + if ((klen > 1 && key[klen-1]==':' && key[klen-2]==':') + || (klen == 1 && key[0] == ':')) { + mro_package_moved( + NULL, GvHV(HeVAL(entry)), + (GV *)HeVAL(entry), 0 + ); } - hv_free_ent(hv, oentry); } - } while (--i >= 0); - - /* As there are no allocated pointers in the aux structure, it's now - safe to free the array we just cleaned up, if it's not the one we're - going to put back. */ - if (array != orig_array) { - Safefree(array); - } - - if (!HvARRAY(hv)) { - /* Good. No-one added anything this time round. */ - break; - } - - if (--attempts == 0) { - Perl_die(aTHX_ "panic: hfreeentries failed to free hash - something is repeatedly re-creating entries"); + hv_free_ent(hv, entry); + /* warning: at this point HvARRAY may have been + * re-allocated, HvMAX changed etc */ + continue; } - } - - /* If the array was not replaced, the rest does not apply. */ - if (HvARRAY(hv) == orig_array) return; - - /* Set aside the current array for now, in case we still need it. */ - if (SvOOK(hv)) current_aux = HvAUX(hv); - if (HvARRAY(hv)) - tmp_array = HvARRAY(hv); - - HvARRAY(hv) = orig_array; - - if (has_aux && current_aux) - SvFLAGS(hv) |= SVf_OOK; - else - SvFLAGS(hv) &=~SVf_OOK; - - /* If the hash was actually a symbol table, put the name and MRO - caches back. */ - if (current_aux) { - struct xpvhv_aux * const aux - = SvOOK(hv) ? HvAUX(hv) : hv_auxinit(hv); - aux->xhv_name_count = current_aux->xhv_name_count; - if(aux->xhv_name_count) - aux->xhv_name_u.xhvnameu_names - = current_aux->xhv_name_u.xhvnameu_names; - else - aux->xhv_name_u.xhvnameu_name - = current_aux->xhv_name_u.xhvnameu_name; - aux->xhv_mro_meta = current_aux->xhv_mro_meta; - } - - if (tmp_array) Safefree(tmp_array); + if (i++ >= HvMAX(hv)) + i = 0; + } /* while */ } /* @@ -1878,17 +1730,10 @@ Perl_hv_undef_flags(pTHX_ HV *hv, U32 flags) if (SvOOK(hv)) { struct xpvhv_aux * const aux = HvAUX(hv); struct mro_meta *meta; - bool zeroed = FALSE; if ((name = HvENAME_get(hv))) { - if (PL_phase != PERL_PHASE_DESTRUCT) { - /* This must come at this point in case - mro_isa_changed_in dies. */ - Zero(HvARRAY(hv), xhv->xhv_max+1 /* HvMAX(hv)+1 */, HE*); - zeroed = TRUE; - + if (PL_phase != PERL_PHASE_DESTRUCT) mro_isa_changed_in(hv); - } if (PL_stashcache) (void)hv_delete( PL_stashcache, name, HvENAMELEN_get(hv), G_DISCARD @@ -1920,10 +1765,8 @@ Perl_hv_undef_flags(pTHX_ HV *hv, U32 flags) Safefree(meta); aux->xhv_mro_meta = NULL; } - if (!aux->xhv_name_u.xhvnameu_name) + if (!aux->xhv_name_u.xhvnameu_name && ! aux->xhv_backreferences) SvFLAGS(hv) &= ~SVf_OOK; - else if (!zeroed) - Zero(HvARRAY(hv), xhv->xhv_max+1 /* HvMAX(hv)+1 */, HE*); } if (!SvOOK(hv)) { Safefree(HvARRAY(hv)); @@ -2001,7 +1844,7 @@ S_hv_auxinit(HV *hv) { =for apidoc hv_iterinit Prepares a starting point to traverse a hash table. Returns the number of -keys in the hash (i.e. the same as C). The return value is +keys in the hash (i.e. the same as C). The return value is currently only meaningful for hashes without tie magic. NOTE: Before version 5.004_65, C used to return the number of @@ -2631,7 +2474,6 @@ S_unshare_hek_or_pvn(pTHX_ const HEK *hek, const char *str, I32 len, U32 hash) register XPVHV* xhv; HE *entry; register HE **oentry; - HE **first; bool is_utf8 = FALSE; int k_flags = 0; const char * const save = str; @@ -2672,7 +2514,7 @@ S_unshare_hek_or_pvn(pTHX_ const HEK *hek, const char *str, I32 len, U32 hash) } */ xhv = (XPVHV*)SvANY(PL_strtab); /* assert(xhv_array != 0) */ - first = oentry = &(HvARRAY(PL_strtab))[hash & (I32) HvMAX(PL_strtab)]; + oentry = &(HvARRAY(PL_strtab))[hash & (I32) HvMAX(PL_strtab)]; if (he) { const HE *const he_he = &(he->shared_he_he); for (entry = *oentry; entry; oentry = &HeNEXT(entry), entry = *oentry) { @@ -2816,7 +2658,7 @@ S_share_hek_flags(pTHX_ const char *str, I32 len, register U32 hash, int flags) xhv->xhv_keys++; /* HvTOTALKEYS(hv)++ */ if (!next) { /* initial entry? */ - } else if (xhv->xhv_keys > xhv->xhv_max /* HvKEYS(hv) > HvMAX(hv) */) { + } else if (xhv->xhv_keys > xhv->xhv_max /* HvUSEDKEYS(hv) > HvMAX(hv) */) { hsplit(PL_strtab); } }