X-Git-Url: https://perl5.git.perl.org/perl5.git/blobdiff_plain/9fe4aecf05bd9db46d8bc10b5508a11d745944f5..d88362caea867f741c6a60e4a573f321c72b32d6:/mro.c diff --git a/mro.c b/mro.c index 9a750fe..2dca25c 100644 --- a/mro.c +++ b/mro.c @@ -1,6 +1,7 @@ /* mro.c * * Copyright (c) 2007 Brandon L Black + * Copyright (c) 2007, 2008 Larry Wall and others * * You may distribute under the terms of either the GNU General Public * License or the Artistic License, as specified in the README file. @@ -8,8 +9,10 @@ */ /* - * "Which order shall we go in?" said Frodo. "Eldest first, or quickest first? - * You'll be last either way, Master Peregrin." + * 'Which order shall we go in?' said Frodo. 'Eldest first, or quickest first? + * You'll be last either way, Master Peregrin.' + * + * [p.101 of _The Lord of the Rings_, I/iii: "A Conspiracy Unmasked"] */ /* @@ -21,29 +24,125 @@ These functions are related to the method resolution order of perl classes */ #include "EXTERN.h" +#define PERL_IN_MRO_C #include "perl.h" +static const struct mro_alg dfs_alg = + {S_mro_get_linear_isa_dfs, "dfs", 3, 0, 0}; + +SV * +Perl_mro_get_private_data(pTHX_ struct mro_meta *const smeta, + const struct mro_alg *const which) +{ + SV **data; + PERL_ARGS_ASSERT_MRO_GET_PRIVATE_DATA; + + data = (SV **)Perl_hv_common(aTHX_ smeta->mro_linear_all, NULL, + which->name, which->length, which->kflags, + HV_FETCH_JUST_SV, NULL, which->hash); + if (!data) + return NULL; + + /* If we've been asked to look up the private data for the current MRO, then + cache it. */ + if (smeta->mro_which == which) + smeta->mro_linear_current = *data; + + return *data; +} + +SV * +Perl_mro_set_private_data(pTHX_ struct mro_meta *const smeta, + const struct mro_alg *const which, SV *const data) +{ + PERL_ARGS_ASSERT_MRO_SET_PRIVATE_DATA; + + if (!smeta->mro_linear_all) { + if (smeta->mro_which == which) { + /* If all we need to store is the current MRO's data, then don't use + memory on a hash with 1 element - store it direct, and signal + this by leaving the would-be-hash NULL. */ + smeta->mro_linear_current = data; + return data; + } else { + HV *const hv = newHV(); + /* Start with 2 buckets. It's unlikely we'll need more. */ + HvMAX(hv) = 1; + smeta->mro_linear_all = hv; + + if (smeta->mro_linear_current) { + /* If we were storing something directly, put it in the hash + before we lose it. */ + Perl_mro_set_private_data(aTHX_ smeta, smeta->mro_which, + smeta->mro_linear_current); + } + } + } + + /* We get here if we're storing more than one linearisation for this stash, + or the linearisation we are storing is not that if its current MRO. */ + + if (smeta->mro_which == which) { + /* If we've been asked to store the private data for the current MRO, + then cache it. */ + smeta->mro_linear_current = data; + } + + if (!Perl_hv_common(aTHX_ smeta->mro_linear_all, NULL, + which->name, which->length, which->kflags, + HV_FETCH_ISSTORE, data, which->hash)) { + Perl_croak(aTHX_ "panic: hv_store() failed in set_mro_private_data() " + "for '%.*s' %d", (int) which->length, which->name, + which->kflags); + } + + return data; +} + +const struct mro_alg * +Perl_mro_get_from_name(pTHX_ SV *name) { + SV **data; + + PERL_ARGS_ASSERT_MRO_GET_FROM_NAME; + + data = (SV **)Perl_hv_common(aTHX_ PL_registered_mros, name, NULL, 0, 0, + HV_FETCH_JUST_SV, NULL, 0); + if (!data) + return NULL; + assert(SvTYPE(*data) == SVt_IV); + assert(SvIOK(*data)); + return INT2PTR(const struct mro_alg *, SvUVX(*data)); +} + +void +Perl_mro_register(pTHX_ const struct mro_alg *mro) { + SV *wrapper = newSVuv(PTR2UV(mro)); + + PERL_ARGS_ASSERT_MRO_REGISTER; + + + if (!Perl_hv_common(aTHX_ PL_registered_mros, NULL, + mro->name, mro->length, mro->kflags, + HV_FETCH_ISSTORE, wrapper, mro->hash)) { + SvREFCNT_dec(wrapper); + Perl_croak(aTHX_ "panic: hv_store() failed in mro_register() " + "for '%.*s' %d", (int) mro->length, mro->name, mro->kflags); + } +} + struct mro_meta* Perl_mro_meta_init(pTHX_ HV* stash) { struct mro_meta* newmeta; - assert(stash); + PERL_ARGS_ASSERT_MRO_META_INIT; assert(HvAUX(stash)); assert(!(HvAUX(stash)->xhv_mro_meta)); - Newxc(newmeta, sizeof(struct mro_meta), char, struct mro_meta); + Newxz(newmeta, 1, struct mro_meta); HvAUX(stash)->xhv_mro_meta = newmeta; - newmeta->sub_generation = 1; - - /* Manually flag UNIVERSAL as being universal. - This happens early in perl booting (when universal.c - does the newXS calls for UNIVERSAL::*), and infects - other packages as they are added to UNIVERSAL's MRO - */ - if(HvNAMELEN_get(stash) == 9 - && strEQ(HEK_KEY(HvAUX(stash)->xhv_name), "UNIVERSAL")) { - HvMROMETA(stash)->is_universal = 1; - } + newmeta->cache_gen = 1; + newmeta->pkg_gen = 1; + newmeta->mro_which = &dfs_alg; return newmeta; } @@ -56,26 +155,30 @@ Perl_mro_meta_dup(pTHX_ struct mro_meta* smeta, CLONE_PARAMS* param) { struct mro_meta* newmeta; - assert(smeta); - - Newxc(newmeta, sizeof(struct mro_meta), char, struct mro_meta); - - newmeta->mro_which = smeta->mro_which; - newmeta->sub_generation = smeta->sub_generation; - newmeta->is_universal = smeta->is_universal; - newmeta->fake = smeta->fake; - newmeta->mro_linear_dfs = smeta->mro_linear_dfs - ? (AV*) SvREFCNT_inc(sv_dup((SV*)smeta->mro_linear_dfs, param)) - : 0; - newmeta->mro_linear_c3 = smeta->mro_linear_c3 - ? (AV*) SvREFCNT_inc(sv_dup((SV*)smeta->mro_linear_c3, param)) - : 0; - newmeta->mro_isarev = smeta->mro_isarev - ? (HV*) SvREFCNT_inc(sv_dup((SV*)smeta->mro_isarev, param)) - : 0; - newmeta->mro_nextmethod = smeta->mro_nextmethod - ? (HV*) SvREFCNT_inc(sv_dup((SV*)smeta->mro_nextmethod, param)) - : 0; + PERL_ARGS_ASSERT_MRO_META_DUP; + + Newx(newmeta, 1, struct mro_meta); + Copy(smeta, newmeta, 1, struct mro_meta); + + if (newmeta->mro_linear_all) { + newmeta->mro_linear_all + = MUTABLE_HV(SvREFCNT_inc(sv_dup((const SV *)newmeta->mro_linear_all, param))); + /* This is just acting as a shortcut pointer, and will be automatically + updated on the first get. */ + newmeta->mro_linear_current = NULL; + } else if (newmeta->mro_linear_current) { + /* Only the current MRO is stored, so this owns the data. */ + newmeta->mro_linear_current + = SvREFCNT_inc(sv_dup((const SV *)newmeta->mro_linear_current, + param)); + } + + if (newmeta->mro_nextmethod) + newmeta->mro_nextmethod + = MUTABLE_HV(SvREFCNT_inc(sv_dup((const SV *)newmeta->mro_nextmethod, param))); + if (newmeta->isa) + newmeta->isa + = MUTABLE_HV(SvREFCNT_inc(sv_dup((const SV *)newmeta->isa, param))); return newmeta; } @@ -90,227 +193,184 @@ the given stash. The return value is a read-only AV*. C should be 0 (it is used internally in this function's recursion). +You are responsible for C on the +return value if you plan to store it anywhere +semi-permanently (otherwise it might be deleted +out from under you the next time the cache is +invalidated). + =cut */ -AV* -Perl_mro_get_linear_isa_dfs(pTHX_ HV *stash, I32 level) +static AV* +S_mro_get_linear_isa_dfs(pTHX_ HV *stash, U32 level) { AV* retval; GV** gvp; GV* gv; AV* av; - SV** svp; - I32 items; - AV* subrv; - SV** subrv_p; - I32 subrv_items; - const char* stashname; + const HEK* stashhek; struct mro_meta* meta; + SV *our_name; + HV *stored = NULL; - assert(stash); + PERL_ARGS_ASSERT_MRO_GET_LINEAR_ISA_DFS; assert(HvAUX(stash)); - stashname = HvNAME_get(stash); - if (!stashname) - Perl_croak(aTHX_ - "Can't linearize anonymous symbol table"); + stashhek = HvNAME_HEK(stash); + if (!stashhek) + Perl_croak(aTHX_ "Can't linearize anonymous symbol table"); if (level > 100) Perl_croak(aTHX_ "Recursive inheritance detected in package '%s'", - stashname); + HEK_KEY(stashhek)); meta = HvMROMETA(stash); - if((retval = meta->mro_linear_dfs)) { - /* return cache if valid */ + + /* return cache if valid */ + if((retval = MUTABLE_AV(MRO_GET_PRIVATE_DATA(meta, &dfs_alg)))) { return retval; } /* not in cache, make a new one */ - retval = newAV(); - av_push(retval, newSVpv(stashname, 0)); /* add ourselves at the top */ + retval = MUTABLE_AV(sv_2mortal(MUTABLE_SV(newAV()))); + /* We use this later in this function, but don't need a reference to it + beyond the end of this function, so reference count is fine. */ + our_name = newSVhek(stashhek); + av_push(retval, our_name); /* add ourselves at the top */ + + /* fetch our @ISA */ gvp = (GV**)hv_fetchs(stash, "ISA", FALSE); av = (gvp && (gv = *gvp) && isGV_with_GP(gv)) ? GvAV(gv) : NULL; - if(av) { - HV* stored = (HV*)sv_2mortal((SV*)newHV()); - svp = AvARRAY(av); - items = AvFILLp(av) + 1; + /* "stored" is used to keep track of all of the classnames we have added to + the MRO so far, so we can do a quick exists check and avoid adding + duplicate classnames to the MRO as we go. + It's then retained to be re-used as a fast lookup for ->isa(), by adding + our own name and "UNIVERSAL" to it. */ + + if(av && AvFILLp(av) >= 0) { + + SV **svp = AvARRAY(av); + I32 items = AvFILLp(av) + 1; + + /* foreach(@ISA) */ while (items--) { SV* const sv = *svp++; HV* const basestash = gv_stashsv(sv, 0); + SV *const *subrv_p; + I32 subrv_items; if (!basestash) { - if(!hv_exists_ent(stored, sv, 0)) { - av_push(retval, newSVsv(sv)); - hv_store_ent(stored, sv, &PL_sv_undef, 0); - } + /* if no stash exists for this @ISA member, + simply add it to the MRO and move on */ + subrv_p = &sv; + subrv_items = 1; } else { - subrv = mro_get_linear_isa_dfs(basestash, level + 1); - subrv_p = AvARRAY(subrv); - subrv_items = AvFILLp(subrv) + 1; - while(subrv_items--) { - SV* subsv = *subrv_p++; - if(!hv_exists_ent(stored, subsv, 0)) { - av_push(retval, newSVsv(subsv)); - hv_store_ent(stored, subsv, &PL_sv_undef, 0); - } - } - } + /* otherwise, recurse into ourselves for the MRO + of this @ISA member, and append their MRO to ours. + The recursive call could throw an exception, which + has memory management implications here, hence the use of + the mortal. */ + const AV *const subrv + = mro_get_linear_isa_dfs(basestash, level + 1); + + subrv_p = AvARRAY(subrv); + subrv_items = AvFILLp(subrv) + 1; + } + if (stored) { + while(subrv_items--) { + SV *const subsv = *subrv_p++; + /* LVALUE fetch will create a new undefined SV if necessary + */ + HE *const he = hv_fetch_ent(stored, subsv, 1, 0); + assert(he); + if(HeVAL(he) != &PL_sv_undef) { + /* It was newly created. Steal it for our new SV, and + replace it in the hash with the "real" thing. */ + SV *const val = HeVAL(he); + HEK *const key = HeKEY_hek(he); + + HeVAL(he) = &PL_sv_undef; + /* Save copying by making a shared hash key scalar. We + inline this here rather than calling + Perl_newSVpvn_share because we already have the + scalar, and we already have the hash key. */ + assert(SvTYPE(val) == SVt_NULL); + sv_upgrade(val, SVt_PV); + SvPV_set(val, HEK_KEY(share_hek_hek(key))); + SvCUR_set(val, HEK_LEN(key)); + SvREADONLY_on(val); + SvFAKE_on(val); + SvPOK_on(val); + if (HEK_UTF8(key)) + SvUTF8_on(val); + + av_push(retval, val); + } + } + } else { + /* We are the first (or only) parent. We can short cut the + complexity above, because our @ISA is simply us prepended + to our parent's @ISA, and our ->isa cache is simply our + parent's, with our name added. */ + /* newSVsv() is slow. This code is only faster if we can avoid + it by ensuring that SVs in the arrays are shared hash key + scalar SVs, because we can "copy" them very efficiently. + Although to be fair, we can't *ensure* this, as a reference + to the internal array is returned by mro::get_linear_isa(), + so we'll have to be defensive just in case someone faffed + with it. */ + if (basestash) { + SV **svp; + stored = MUTABLE_HV(sv_2mortal((SV*)newHVhv(HvMROMETA(basestash)->isa))); + av_extend(retval, subrv_items); + AvFILLp(retval) = subrv_items; + svp = AvARRAY(retval); + while(subrv_items--) { + SV *const val = *subrv_p++; + *++svp = SvIsCOW_shared_hash(val) + ? newSVhek(SvSHARED_HEK_FROM_PV(SvPVX(val))) + : newSVsv(val); + } + } else { + /* They have no stash. So create ourselves an ->isa cache + as if we'd copied it from what theirs should be. */ + stored = MUTABLE_HV(sv_2mortal(MUTABLE_SV(newHV()))); + (void) hv_store(stored, "UNIVERSAL", 9, &PL_sv_undef, 0); + av_push(retval, + newSVhek(HeKEY_hek(hv_store_ent(stored, sv, + &PL_sv_undef, 0)))); + } + } } + } else { + /* We have no parents. */ + stored = MUTABLE_HV(sv_2mortal(MUTABLE_SV(newHV()))); + (void) hv_store(stored, "UNIVERSAL", 9, &PL_sv_undef, 0); } - SvREADONLY_on(retval); - meta->mro_linear_dfs = retval; - return retval; -} + (void) hv_store_ent(stored, our_name, &PL_sv_undef, 0); -/* -=for apidoc mro_get_linear_isa_c3 + SvREFCNT_inc_simple_void_NN(stored); + SvTEMP_off(stored); + SvREADONLY_on(stored); -Returns the C3 linearization of @ISA -the given stash. The return value is a read-only AV*. -C should be 0 (it is used internally in this -function's recursion). + meta->isa = stored; -=cut -*/ - -AV* -Perl_mro_get_linear_isa_c3(pTHX_ HV* stash, I32 level) -{ - AV* retval; - GV** gvp; - GV* gv; - AV* isa; - const char* stashname; - STRLEN stashname_len; - struct mro_meta* meta; - - assert(stash); - assert(HvAUX(stash)); - - stashname = HvNAME_get(stash); - stashname_len = HvNAMELEN_get(stash); - if (!stashname) - Perl_croak(aTHX_ - "Can't linearize anonymous symbol table"); - - if (level > 100) - Perl_croak(aTHX_ "Recursive inheritance detected in package '%s'", - stashname); - - meta = HvMROMETA(stash); - if((retval = meta->mro_linear_c3)) { - /* return cache if valid */ - return retval; - } - - /* not in cache, make a new one */ - - retval = newAV(); - av_push(retval, newSVpvn(stashname, stashname_len)); /* us first */ - - gvp = (GV**)hv_fetchs(stash, "ISA", FALSE); - isa = (gvp && (gv = *gvp) && isGV_with_GP(gv)) ? GvAV(gv) : NULL; - - if(isa && AvFILLp(isa) >= 0) { - SV** seqs_ptr; - I32 seqs_items; - HV* tails = (HV*)sv_2mortal((SV*)newHV()); - AV* seqs = (AV*)sv_2mortal((SV*)newAV()); - I32 items = AvFILLp(isa) + 1; - SV** isa_ptr = AvARRAY(isa); - while(items--) { - AV* isa_lin; - SV* isa_item = *isa_ptr++; - HV* isa_item_stash = gv_stashsv(isa_item, 0); - if(!isa_item_stash) { - isa_lin = newAV(); - av_push(isa_lin, newSVsv(isa_item)); - } - else { - isa_lin = mro_get_linear_isa_c3(isa_item_stash, level + 1); /* recursion */ - } - av_push(seqs, (SV*)av_make(AvFILLp(isa_lin)+1, AvARRAY(isa_lin))); - } - av_push(seqs, (SV*)av_make(AvFILLp(isa)+1, AvARRAY(isa))); - - seqs_ptr = AvARRAY(seqs); - seqs_items = AvFILLp(seqs) + 1; - while(seqs_items--) { - AV* seq = (AV*)*seqs_ptr++; - I32 seq_items = AvFILLp(seq); - if(seq_items > 0) { - SV** seq_ptr = AvARRAY(seq) + 1; - while(seq_items--) { - SV* seqitem = *seq_ptr++; - HE* he = hv_fetch_ent(tails, seqitem, 0, 0); - if(!he) { - hv_store_ent(tails, seqitem, newSViv(1), 0); - } - else { - SV* val = HeVAL(he); - sv_inc(val); - } - } - } - } - - while(1) { - SV* seqhead = NULL; - SV* cand = NULL; - SV* winner = NULL; - SV* val; - HE* tail_entry; - AV* seq; - SV** avptr = AvARRAY(seqs); - items = AvFILLp(seqs)+1; - while(items--) { - SV** svp; - seq = (AV*)*avptr++; - if(AvFILLp(seq) < 0) continue; - svp = av_fetch(seq, 0, 0); - seqhead = *svp; - if(!winner) { - cand = seqhead; - if((tail_entry = hv_fetch_ent(tails, cand, 0, 0)) - && (val = HeVAL(tail_entry)) - && (SvIVx(val) > 0)) - continue; - winner = newSVsv(cand); - av_push(retval, winner); - } - if(!sv_cmp(seqhead, winner)) { - - /* this is basically shift(@seq) in void context */ - SvREFCNT_dec(*AvARRAY(seq)); - *AvARRAY(seq) = &PL_sv_undef; - AvARRAY(seq) = AvARRAY(seq) + 1; - AvMAX(seq)--; - AvFILLp(seq)--; - - if(AvFILLp(seq) < 0) continue; - svp = av_fetch(seq, 0, 0); - seqhead = *svp; - tail_entry = hv_fetch_ent(tails, seqhead, 0, 0); - val = HeVAL(tail_entry); - sv_dec(val); - } - } - if(!cand) break; - if(!winner) { - SvREFCNT_dec(retval); - Perl_croak(aTHX_ "Inconsistent hierarchy during C3 merge of class '%s': " - "merging failed on parent '%"SVf"'", stashname, SVfARG(cand)); - } - } - } + /* now that we're past the exception dangers, grab our own reference to + the AV we're about to use for the result. The reference owned by the + mortals' stack will be released soon, so everything will balance. */ + SvREFCNT_inc_simple_void_NN(retval); + SvTEMP_off(retval); + /* we don't want anyone modifying the cache entry but us, + and we do so by replacing it completely */ SvREADONLY_on(retval); - meta->mro_linear_c3 = retval; - return retval; + + return MUTABLE_AV(Perl_mro_set_private_data(aTHX_ meta, &dfs_alg, + MUTABLE_SV(retval))); } /* @@ -322,29 +382,33 @@ dependant upon which MRO is in effect for that stash. The return value is a read-only AV*. +You are responsible for C on the +return value if you plan to store it anywhere +semi-permanently (otherwise it might be deleted +out from under you the next time the cache is +invalidated). + =cut */ AV* Perl_mro_get_linear_isa(pTHX_ HV *stash) { struct mro_meta* meta; - assert(stash); - assert(HvAUX(stash)); + + PERL_ARGS_ASSERT_MRO_GET_LINEAR_ISA; + if(!SvOOK(stash)) + Perl_croak(aTHX_ "Can't linearize anonymous symbol table"); meta = HvMROMETA(stash); - if(meta->mro_which == MRO_DFS) { - return mro_get_linear_isa_dfs(stash, 0); - } else if(meta->mro_which == MRO_C3) { - return mro_get_linear_isa_c3(stash, 0); - } else { + if (!meta->mro_which) Perl_croak(aTHX_ "panic: invalid MRO!"); - } + return meta->mro_which->resolve(aTHX_ stash, 0); } /* =for apidoc mro_isa_changed_in -Takes the neccesary steps (cache invalidations, mostly) +Takes the necessary steps (cache invalidations, mostly) when the @ISA of the given package has changed. Invoked by the C magic, should not need to invoke directly. @@ -359,90 +423,127 @@ Perl_mro_isa_changed_in(pTHX_ HV* stash) HE* iter; SV** svp; I32 items; - struct mro_meta* meta; - char* stashname; + bool is_universal; + struct mro_meta * meta; - stashname = HvNAME_get(stash); + const char * const stashname = HvNAME_get(stash); + const STRLEN stashname_len = HvNAMELEN_get(stash); + + PERL_ARGS_ASSERT_MRO_ISA_CHANGED_IN; + + if(!stashname) + Perl_croak(aTHX_ "Can't call mro_isa_changed_in() on anonymous symbol table"); /* wipe out the cached linearizations for this stash */ meta = HvMROMETA(stash); - SvREFCNT_dec((SV*)meta->mro_linear_dfs); - SvREFCNT_dec((SV*)meta->mro_linear_c3); - meta->mro_linear_dfs = NULL; - meta->mro_linear_c3 = NULL; + if (meta->mro_linear_all) { + SvREFCNT_dec(MUTABLE_SV(meta->mro_linear_all)); + meta->mro_linear_all = NULL; + /* This is just acting as a shortcut pointer. */ + meta->mro_linear_current = NULL; + } else if (meta->mro_linear_current) { + /* Only the current MRO is stored, so this owns the data. */ + SvREFCNT_dec(meta->mro_linear_current); + meta->mro_linear_current = NULL; + } + if (meta->isa) { + SvREFCNT_dec(meta->isa); + meta->isa = NULL; + } + + /* Inc the package generation, since our @ISA changed */ + meta->pkg_gen++; /* Wipe the global method cache if this package is UNIVERSAL or one of its parents */ - if(meta->is_universal) - PL_sub_generation++; - /* Wipe the local method cache otherwise */ - else - meta->sub_generation++; + svp = hv_fetch(PL_isarev, stashname, stashname_len, 0); + isarev = svp ? MUTABLE_HV(*svp) : NULL; + + if((stashname_len == 9 && strEQ(stashname, "UNIVERSAL")) + || (isarev && hv_exists(isarev, "UNIVERSAL", 9))) { + PL_sub_generation++; + is_universal = TRUE; + } + else { /* Wipe the local method cache otherwise */ + meta->cache_gen++; + is_universal = FALSE; + } /* wipe next::method cache too */ if(meta->mro_nextmethod) hv_clear(meta->mro_nextmethod); - + /* Iterate the isarev (classes that are our children), - wiping out their linearization and method caches */ - if((isarev = meta->mro_isarev)) { + wiping out their linearization, method and isa caches */ + if(isarev) { hv_iterinit(isarev); while((iter = hv_iternext(isarev))) { - SV* revkey = hv_iterkeysv(iter); - HV* revstash = gv_stashsv(revkey, 0); - struct mro_meta* revmeta = HvMROMETA(revstash); - SvREFCNT_dec((SV*)revmeta->mro_linear_dfs); - SvREFCNT_dec((SV*)revmeta->mro_linear_c3); - revmeta->mro_linear_dfs = NULL; - revmeta->mro_linear_c3 = NULL; - if(!meta->is_universal) - revmeta->sub_generation++; + I32 len; + const char* const revkey = hv_iterkey(iter, &len); + HV* revstash = gv_stashpvn(revkey, len, 0); + struct mro_meta* revmeta; + + if(!revstash) continue; + revmeta = HvMROMETA(revstash); + if (revmeta->mro_linear_all) { + SvREFCNT_dec(MUTABLE_SV(revmeta->mro_linear_all)); + revmeta->mro_linear_all = NULL; + /* This is just acting as a shortcut pointer. */ + revmeta->mro_linear_current = NULL; + } else if (revmeta->mro_linear_current) { + /* Only the current MRO is stored, so this owns the data. */ + SvREFCNT_dec(revmeta->mro_linear_current); + revmeta->mro_linear_current = NULL; + } + if(!is_universal) + revmeta->cache_gen++; if(revmeta->mro_nextmethod) hv_clear(revmeta->mro_nextmethod); + if (revmeta->isa) { + SvREFCNT_dec(revmeta->isa); + revmeta->isa = NULL; + } } } - /* we're starting at the 2nd element, skipping ourselves here */ + /* Now iterate our MRO (parents), and do a few things: + 1) instantiate with the "fake" flag if they don't exist + 2) flag them as universal if we are universal + 3) Add everything from our isarev to their isarev + */ + + /* We're starting at the 2nd element, skipping ourselves here */ linear_mro = mro_get_linear_isa(stash); svp = AvARRAY(linear_mro) + 1; items = AvFILLp(linear_mro); + while (items--) { SV* const sv = *svp++; - struct mro_meta* mrometa; HV* mroisarev; - HV* mrostash = gv_stashsv(sv, 0); - if(!mrostash) { - mrostash = gv_stashsv(sv, GV_ADD); - /* - We created the package on the fly, so - that we could store isarev information. - This flag lets gv_fetchmeth know about it, - so that it can still generate the very useful - "Can't locate package Foo for @Bar::ISA" warning. - */ - HvMROMETA(mrostash)->fake = 1; - } + HE *he = hv_fetch_ent(PL_isarev, sv, TRUE, 0); - mrometa = HvMROMETA(mrostash); - mroisarev = mrometa->mro_isarev; + /* That fetch should not fail. But if it had to create a new SV for + us, then will need to upgrade it to an HV (which sv_upgrade() can + now do for us. */ - /* is_universal is viral */ - if(meta->is_universal) - mrometa->is_universal = 1; + mroisarev = MUTABLE_HV(HeVAL(he)); - if(!mroisarev) - mroisarev = mrometa->mro_isarev = newHV(); + SvUPGRADE(MUTABLE_SV(mroisarev), SVt_PVHV); - if(!hv_exists(mroisarev, stashname, strlen(stashname))) - hv_store(mroisarev, stashname, strlen(stashname), &PL_sv_yes, 0); + /* This hash only ever contains PL_sv_yes. Storing it over itself is + almost as cheap as calling hv_exists, so on aggregate we expect to + save time by not making two calls to the common HV code for the + case where it doesn't exist. */ + + (void)hv_store(mroisarev, stashname, stashname_len, &PL_sv_yes, 0); if(isarev) { hv_iterinit(isarev); while((iter = hv_iternext(isarev))) { - SV* revkey = hv_iterkeysv(iter); - if(!hv_exists_ent(mroisarev, revkey, 0)) - hv_store_ent(mroisarev, revkey, &PL_sv_yes, 0); + I32 revkeylen; + char* const revkey = hv_iterkey(iter, &revkeylen); + (void)hv_store(mroisarev, revkey, revkeylen, &PL_sv_yes, 0); } } } @@ -451,475 +552,120 @@ Perl_mro_isa_changed_in(pTHX_ HV* stash) /* =for apidoc mro_method_changed_in -Like C, but invalidates method -caching on any child classes of the given stash, so -that they might notice the changes in this one. +Invalidates method caching on any child classes +of the given stash, so that they might notice +the changes in this one. Ideally, all instances of C in -the perl source should be replaced by calls to this. -Some already are, but some are more difficult to -replace. +perl source outside of C should be +replaced by calls to this. + +Perl automatically handles most of the common +ways a method might be redefined. However, there +are a few ways you could change a method in a stash +without the cache code noticing, in which case you +need to call this method afterwards: + +1) Directly manipulating the stash HV entries from +XS code. -Perl has always had problems with method caches -getting out of sync when one directly manipulates -stashes via things like C<%{Foo::} = %{Bar::}> or -C<${Foo::}{bar} = ...> or the equivalent. If -you do this in core or XS code, call this afterwards -on the destination stash to get things back in sync. +2) Assigning a reference to a readonly scalar +constant into a stash entry in order to create +a constant subroutine (like constant.pm +does). -If you're doing such a thing from pure perl, use -C, which -just calls this. +This same method is available from pure perl +via, C. =cut */ void Perl_mro_method_changed_in(pTHX_ HV *stash) { - struct mro_meta* meta = HvMROMETA(stash); - HV* isarev; - HE* iter; + const char * const stashname = HvNAME_get(stash); + const STRLEN stashname_len = HvNAMELEN_get(stash); + + SV ** const svp = hv_fetch(PL_isarev, stashname, stashname_len, 0); + HV * const isarev = svp ? MUTABLE_HV(*svp) : NULL; + + PERL_ARGS_ASSERT_MRO_METHOD_CHANGED_IN; + + if(!stashname) + Perl_croak(aTHX_ "Can't call mro_method_changed_in() on anonymous symbol table"); + + /* Inc the package generation, since a local method changed */ + HvMROMETA(stash)->pkg_gen++; /* If stash is UNIVERSAL, or one of UNIVERSAL's parents, invalidate all method caches globally */ - if(meta->is_universal) { + if((stashname_len == 9 && strEQ(stashname, "UNIVERSAL")) + || (isarev && hv_exists(isarev, "UNIVERSAL", 9))) { PL_sub_generation++; return; } /* else, invalidate the method caches of all child classes, but not itself */ - if((isarev = meta->mro_isarev)) { + if(isarev) { + HE* iter; + hv_iterinit(isarev); while((iter = hv_iternext(isarev))) { - SV* revkey = hv_iterkeysv(iter); - HV* revstash = gv_stashsv(revkey, 0); - struct mro_meta* mrometa = HvMROMETA(revstash); - mrometa->sub_generation++; + I32 len; + const char* const revkey = hv_iterkey(iter, &len); + HV* const revstash = gv_stashpvn(revkey, len, 0); + struct mro_meta* mrometa; + + if(!revstash) continue; + mrometa = HvMROMETA(revstash); + mrometa->cache_gen++; if(mrometa->mro_nextmethod) hv_clear(mrometa->mro_nextmethod); } } } -/* These two are static helpers for next::method and friends, - and re-implement a bunch of the code from pp_caller() in - a more efficient manner for this particular usage. -*/ - -STATIC I32 -__dopoptosub_at(const PERL_CONTEXT *cxstk, I32 startingblock) { - I32 i; - for (i = startingblock; i >= 0; i--) { - if(CxTYPE((PERL_CONTEXT*)(&cxstk[i])) == CXt_SUB) return i; - } - return i; -} - -STATIC SV* -__nextcan(pTHX_ SV* self, I32 throw_nomethod) -{ - register I32 cxix; - register const PERL_CONTEXT *ccstack = cxstack; - const PERL_SI *top_si = PL_curstackinfo; - HV* selfstash; - GV* cvgv; - SV *stashname; - const char *fq_subname; - const char *subname; - STRLEN fq_subname_len; - STRLEN stashname_len; - STRLEN subname_len; - SV* sv; - GV** gvp; - AV* linear_av; - SV** linear_svp; - SV* linear_sv; - HV* curstash; - GV* candidate = NULL; - CV* cand_cv = NULL; - const char *hvname; - I32 items; - struct mro_meta* selfmeta; - HV* nmcache; - HE* cache_entry; - - if(sv_isobject(self)) - selfstash = SvSTASH(SvRV(self)); - else - selfstash = gv_stashsv(self, 0); - - assert(selfstash); - - hvname = HvNAME_get(selfstash); - if (!hvname) - Perl_croak(aTHX_ "Can't use anonymous symbol table for method lookup"); - - cxix = __dopoptosub_at(cxstack, cxstack_ix); - - /* This block finds the contextually-enclosing fully-qualified subname, - much like looking at (caller($i))[3] until you find a real sub that - isn't ANON, etc */ - for (;;) { - /* we may be in a higher stacklevel, so dig down deeper */ - while (cxix < 0) { - if(top_si->si_type == PERLSI_MAIN) - Perl_croak(aTHX_ "next::method/next::can/maybe::next::method must be used in method context"); - top_si = top_si->si_prev; - ccstack = top_si->si_cxstack; - cxix = __dopoptosub_at(ccstack, top_si->si_cxix); - } - - if(CxTYPE((PERL_CONTEXT*)(&ccstack[cxix])) != CXt_SUB - || (PL_DBsub && GvCV(PL_DBsub) && ccstack[cxix].blk_sub.cv == GvCV(PL_DBsub))) { - cxix = __dopoptosub_at(ccstack, cxix - 1); - continue; - } - - { - const I32 dbcxix = __dopoptosub_at(ccstack, cxix - 1); - if (PL_DBsub && GvCV(PL_DBsub) && dbcxix >= 0 && ccstack[dbcxix].blk_sub.cv == GvCV(PL_DBsub)) { - if(CxTYPE((PERL_CONTEXT*)(&ccstack[dbcxix])) != CXt_SUB) { - cxix = dbcxix; - continue; - } - } - } - - cvgv = CvGV(ccstack[cxix].blk_sub.cv); - - if(!isGV(cvgv)) { - cxix = __dopoptosub_at(ccstack, cxix - 1); - continue; - } - - /* we found a real sub here */ - sv = sv_2mortal(newSV(0)); - - gv_efullname3(sv, cvgv, NULL); - - fq_subname = SvPVX(sv); - fq_subname_len = SvCUR(sv); - - subname = strrchr(fq_subname, ':'); - if(!subname) - Perl_croak(aTHX_ "next::method/next::can/maybe::next::method cannot find enclosing method"); - - subname++; - subname_len = fq_subname_len - (subname - fq_subname); - if(subname_len == 8 && strEQ(subname, "__ANON__")) { - cxix = __dopoptosub_at(ccstack, cxix - 1); - continue; - } - break; - } - - /* If we made it to here, we found our context */ - - selfmeta = HvMROMETA(selfstash); - if(!(nmcache = selfmeta->mro_nextmethod)) { - nmcache = selfmeta->mro_nextmethod = newHV(); - } - - if((cache_entry = hv_fetch_ent(nmcache, sv, 0, 0))) { - SV* val = HeVAL(cache_entry); - if(val == &PL_sv_undef) { - if(throw_nomethod) - Perl_croak(aTHX_ "No next::method '%s' found for %s", subname, hvname); - } - return val; - } - - /* beyond here is just for cache misses, so perf isn't as critical */ - - stashname_len = subname - fq_subname - 2; - stashname = sv_2mortal(newSVpvn(fq_subname, stashname_len)); - - linear_av = mro_get_linear_isa_c3(selfstash, 0); /* has ourselves at the top of the list */ - - linear_svp = AvARRAY(linear_av); - items = AvFILLp(linear_av) + 1; - - while (items--) { - linear_sv = *linear_svp++; - assert(linear_sv); - if(sv_eq(linear_sv, stashname)) - break; - } - - if(items > 0) { - while (items--) { - linear_sv = *linear_svp++; - assert(linear_sv); - curstash = gv_stashsv(linear_sv, FALSE); - - if (!curstash || (HvMROMETA(curstash)->fake && !HvFILL(curstash))) { - if (ckWARN(WARN_SYNTAX)) - Perl_warner(aTHX_ packWARN(WARN_SYNTAX), "Can't locate package %"SVf" for @%s::ISA", - (void*)linear_sv, hvname); - continue; - } - - assert(curstash); - - gvp = (GV**)hv_fetch(curstash, subname, subname_len, 0); - if (!gvp) continue; - - candidate = *gvp; - assert(candidate); - - if (SvTYPE(candidate) != SVt_PVGV) - gv_init(candidate, curstash, subname, subname_len, TRUE); - if (SvTYPE(candidate) == SVt_PVGV && (cand_cv = GvCV(candidate)) && !GvCVGEN(candidate)) { - SvREFCNT_inc_simple_void_NN((SV*)cand_cv); - hv_store_ent(nmcache, newSVsv(sv), (SV*)cand_cv, 0); - return (SV*)cand_cv; - } - } - } - - hv_store_ent(nmcache, newSVsv(sv), &PL_sv_undef, 0); - if(throw_nomethod) - Perl_croak(aTHX_ "No next::method '%s' found for %s", subname, hvname); - return &PL_sv_undef; -} - -#include "XSUB.h" - -XS(XS_mro_get_linear_isa); -XS(XS_mro_set_mro); -XS(XS_mro_get_mro); -XS(XS_mro_get_isarev); -XS(XS_mro_is_universal); -XS(XS_mro_get_global_sub_generation); -XS(XS_mro_invalidate_all_method_caches); -XS(XS_mro_get_sub_generation); -XS(XS_mro_method_changed_in); -XS(XS_next_can); -XS(XS_next_method); -XS(XS_maybe_next_method); - void -Perl_boot_core_mro(pTHX) -{ - dVAR; - static const char file[] = __FILE__; - - newXSproto("mro::get_linear_isa", XS_mro_get_linear_isa, file, "$;$"); - newXSproto("mro::set_mro", XS_mro_set_mro, file, "$$"); - newXSproto("mro::get_mro", XS_mro_get_mro, file, "$"); - newXSproto("mro::get_isarev", XS_mro_get_isarev, file, "$"); - newXSproto("mro::is_universal", XS_mro_is_universal, file, "$"); - newXSproto("mro::get_global_sub_generation", XS_mro_get_global_sub_generation, file, ""); - newXSproto("mro::invalidate_all_method_caches", XS_mro_invalidate_all_method_caches, file, ""); - newXSproto("mro::get_sub_generation", XS_mro_get_sub_generation, file, "$"); - newXSproto("mro::method_changed_in", XS_mro_method_changed_in, file, "$"); - newXS("next::can", XS_next_can, file); - newXS("next::method", XS_next_method, file); - newXS("maybe::next::method", XS_maybe_next_method, file); -} - -XS(XS_mro_get_linear_isa) { - dVAR; - dXSARGS; - AV* RETVAL; - HV* class_stash; - SV* classname; - - PERL_UNUSED_ARG(cv); - - if(items < 1 || items > 2) - Perl_croak(aTHX_ "Usage: mro::get_linear_isa(classname [, type ])"); - - classname = ST(0); - class_stash = gv_stashsv(classname, 0); - if(!class_stash) Perl_croak(aTHX_ "No such class: '%"SVf"'!", SVfARG(classname)); - - if(items > 1) { - char* which = SvPV_nolen(ST(1)); - if(strEQ(which, "dfs")) - RETVAL = mro_get_linear_isa_dfs(class_stash, 0); - else if(strEQ(which, "c3")) - RETVAL = mro_get_linear_isa_c3(class_stash, 0); - else - Perl_croak(aTHX_ "Invalid mro name: '%s'", which); - } - else { - RETVAL = mro_get_linear_isa(class_stash); - } - - ST(0) = newRV_inc((SV*)RETVAL); - sv_2mortal(ST(0)); - XSRETURN(1); -} - -XS(XS_mro_set_mro) +Perl_mro_set_mro(pTHX_ struct mro_meta *const meta, SV *const name) { - dVAR; - dXSARGS; - SV* classname; - char* whichstr; - mro_alg which; - HV* class_stash; - struct mro_meta* meta; - - PERL_UNUSED_ARG(cv); + const struct mro_alg *const which = Perl_mro_get_from_name(aTHX_ name); + + PERL_ARGS_ASSERT_MRO_SET_MRO; - if (items != 2) - Perl_croak(aTHX_ "Usage: mro::set_mro(classname, type)"); - - classname = ST(0); - whichstr = SvPV_nolen(ST(1)); - class_stash = gv_stashsv(classname, GV_ADD); - if(!class_stash) Perl_croak(aTHX_ "Cannot create class: '%"SVf"'!", SVfARG(classname)); - meta = HvMROMETA(class_stash); - - if(strEQ(whichstr, "dfs")) - which = MRO_DFS; - else if(strEQ(whichstr, "c3")) - which = MRO_C3; - else - Perl_croak(aTHX_ "Invalid mro name: '%s'", whichstr); + if (!which) + Perl_croak(aTHX_ "Invalid mro name: '%"SVf"'", name); if(meta->mro_which != which) { - meta->mro_which = which; + if (meta->mro_linear_current && !meta->mro_linear_all) { + /* If we were storing something directly, put it in the hash before + we lose it. */ + Perl_mro_set_private_data(aTHX_ meta, meta->mro_which, + MUTABLE_SV(meta->mro_linear_current)); + } + meta->mro_which = which; + /* Scrub our cached pointer to the private data. */ + meta->mro_linear_current = NULL; /* Only affects local method cache, not even child classes */ - meta->sub_generation++; + meta->cache_gen++; if(meta->mro_nextmethod) hv_clear(meta->mro_nextmethod); } - - XSRETURN_EMPTY; } +#include "XSUB.h" -XS(XS_mro_get_mro) -{ - dVAR; - dXSARGS; - SV* classname; - HV* class_stash; - struct mro_meta* meta; - - PERL_UNUSED_ARG(cv); - - if (items != 1) - Perl_croak(aTHX_ "Usage: mro::get_mro(classname)"); - - classname = ST(0); - class_stash = gv_stashsv(classname, 0); - if(!class_stash) Perl_croak(aTHX_ "No such class: '%"SVf"'!", SVfARG(classname)); - meta = HvMROMETA(class_stash); - - if(meta->mro_which == MRO_DFS) - ST(0) = sv_2mortal(newSVpvn("dfs", 3)); - else - ST(0) = sv_2mortal(newSVpvn("c3", 2)); - - XSRETURN(1); -} - -XS(XS_mro_get_isarev) -{ - dVAR; - dXSARGS; - SV* classname; - HV* class_stash; - HV* isarev; - - PERL_UNUSED_ARG(cv); - - if (items != 1) - Perl_croak(aTHX_ "Usage: mro::get_isarev(classname)"); - - classname = ST(0); - - class_stash = gv_stashsv(classname, 0); - if(!class_stash) Perl_croak(aTHX_ "No such class: '%"SVf"'!", SVfARG(classname)); - - SP -= items; - - if((isarev = HvMROMETA(class_stash)->mro_isarev)) { - HE* iter; - hv_iterinit(isarev); - while((iter = hv_iternext(isarev))) - XPUSHs(hv_iterkeysv(iter)); - } - - PUTBACK; - return; -} - -XS(XS_mro_is_universal) -{ - dVAR; - dXSARGS; - SV* classname; - HV* class_stash; - - PERL_UNUSED_ARG(cv); - - if (items != 1) - Perl_croak(aTHX_ "Usage: mro::get_mro(classname)"); - - classname = ST(0); - class_stash = gv_stashsv(classname, 0); - if(!class_stash) Perl_croak(aTHX_ "No such class: '%"SVf"'!", SVfARG(classname)); - - if (HvMROMETA(class_stash)->is_universal) - XSRETURN_YES; - else - XSRETURN_NO; -} - -XS(XS_mro_get_global_sub_generation) -{ - dVAR; - dXSARGS; - - PERL_UNUSED_ARG(cv); - - if (items != 0) - Perl_croak(aTHX_ "Usage: mro::get_global_sub_generation()"); - - ST(0) = sv_2mortal(newSViv(PL_sub_generation)); - XSRETURN(1); -} - -XS(XS_mro_invalidate_all_method_caches) -{ - dVAR; - dXSARGS; - - PERL_UNUSED_ARG(cv); - - if (items != 0) - Perl_croak(aTHX_ "Usage: mro::invalidate_all_method_caches()"); - - PL_sub_generation++; - - XSRETURN_EMPTY; -} +XS(XS_mro_method_changed_in); -XS(XS_mro_get_sub_generation) +void +Perl_boot_core_mro(pTHX) { dVAR; - dXSARGS; - SV* classname; - HV* class_stash; - - PERL_UNUSED_ARG(cv); - - if(items != 1) - Perl_croak(aTHX_ "Usage: mro::get_sub_generation(classname)"); + static const char file[] = __FILE__; - classname = ST(0); - class_stash = gv_stashsv(classname, 0); - if(!class_stash) Perl_croak(aTHX_ "No such class: '%"SVf"'!", SVfARG(classname)); + Perl_mro_register(aTHX_ &dfs_alg); - ST(0) = sv_2mortal(newSViv(HvMROMETA(class_stash)->sub_generation)); - XSRETURN(1); + newXSproto("mro::method_changed_in", XS_mro_method_changed_in, file, "$"); } XS(XS_mro_method_changed_in) @@ -929,10 +675,8 @@ XS(XS_mro_method_changed_in) SV* classname; HV* class_stash; - PERL_UNUSED_ARG(cv); - if(items != 1) - Perl_croak(aTHX_ "Usage: mro::method_changed_in(classname)"); + croak_xs_usage(cv, "classname"); classname = ST(0); @@ -944,57 +688,6 @@ XS(XS_mro_method_changed_in) XSRETURN_EMPTY; } -XS(XS_next_can) -{ - dVAR; - dXSARGS; - SV* self = ST(0); - SV* methcv = __nextcan(aTHX_ self, 0); - - PERL_UNUSED_ARG(cv); - PERL_UNUSED_VAR(items); - - if(methcv == &PL_sv_undef) { - ST(0) = &PL_sv_undef; - } - else { - ST(0) = sv_2mortal(newRV_inc(methcv)); - } - - XSRETURN(1); -} - -XS(XS_next_method) -{ - dMARK; - dAX; - SV* self = ST(0); - SV* methcv = __nextcan(aTHX_ self, 1); - - PERL_UNUSED_ARG(cv); - - PL_markstack_ptr++; - call_sv(methcv, GIMME_V); -} - -XS(XS_maybe_next_method) -{ - dMARK; - dAX; - SV* self = ST(0); - SV* methcv = __nextcan(aTHX_ self, 0); - - PERL_UNUSED_ARG(cv); - - if(methcv == &PL_sv_undef) { - ST(0) = &PL_sv_undef; - XSRETURN(1); - } - - PL_markstack_ptr++; - call_sv(methcv, GIMME_V); -} - /* * Local variables: * c-indentation-style: bsd