diff options
Diffstat (limited to 'hv.c')
| -rw-r--r-- | hv.c | 24 |
1 files changed, 15 insertions, 9 deletions
@@ -798,17 +798,23 @@ Perl_hv_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen, if ( DO_HSPLIT(xhv) ) { const STRLEN oldsize = xhv->xhv_max + 1; - /* This logic was in S_hsplit, but as the shared string table can't - contain placeholders, and we are the only other caller of S_hsplit, - it could only trigger from this callsite. So move it here. */ - if (HvPLACEHOLDERS_get(hv) && !SvREADONLY(hv)) { - /* Can make this clear any placeholders first for non-restricted - hashes, even though Storable rebuilds restricted hashes by + if (HvPLACEHOLDERS_get(hv) /* hash has placeholders */ + && !SvREADONLY(hv) /* but is not a restricted hash */) { + /* If this hash previously was a "restricted hash" and had + placeholders, but the "restricted" flag has been turned off, + then the placeholders no longer serve any useful purpose. + However, they have the downsides of taking up RAM, and adding + extra steps when finding used values. It's safe to clear them + at this point, even though Storable rebuilds restricted hashes by putting in all the placeholders (first) before turning on the - readonly flag, because Storable always pre-splits the hash. */ + readonly flag, because Storable always pre-splits the hash. + If we're lucky, then we may clear sufficient placeholders to + avoid needing to split the hash at all. */ hv_clear_placeholders(hv); - } - hsplit(hv, oldsize, oldsize * 2); + if (DO_HSPLIT(xhv)) + hsplit(hv, oldsize, oldsize * 2); + } else + hsplit(hv, oldsize, oldsize * 2); } if (return_svp) { |