From a76a30724dfdfd26938960d2f756b4d97f8d855e Mon Sep 17 00:00:00 2001 From: Koichi Sasada Date: Tue, 20 Oct 2020 01:34:17 +0900 Subject: [PATCH] Revert "reduce lock for encoding" This reverts commit de17e2dea137bc5ba9f00e3acec32792d0dbb2eb. This patch can introduce race condition because of conflicting read/write access for enc_table::default_list. Maybe we need to freeze default_list at the end of Init_encdb() in enc/encdb.c. --- encoding.c | 125 +++++++++++++++++++++++------------------------------ 1 file changed, 53 insertions(+), 72 deletions(-) diff --git a/encoding.c b/encoding.c index cd3738426a..7f798cd78d 100644 --- a/encoding.c +++ b/encoding.c @@ -68,11 +68,9 @@ struct rb_encoding_entry { }; static struct enc_table { - // default_list + additional_list - struct rb_encoding_entry default_list[DEFAULT_ENCODING_LIST_CAPA]; - struct rb_encoding_entry *additional_list; - int additional_list_size; + struct rb_encoding_entry *list; int count; + int size; st_table *names; } global_enc_table; @@ -350,54 +348,24 @@ rb_find_encoding(VALUE enc) } static int -enc_table_expand(struct enc_table *enc_table, const int newsize) +enc_table_expand(struct enc_table *enc_table, int newsize) { - if (newsize <= DEFAULT_ENCODING_LIST_CAPA) { - // ok - } - else { - int add_size = newsize - DEFAULT_ENCODING_LIST_CAPA; - if (add_size <= enc_table->additional_list_size) { - // ok - } - else { - struct rb_encoding_entry *ent; - add_size = (add_size + 7) / 8 * 8; + struct rb_encoding_entry *ent; + int count = newsize; - if (enc_table->additional_list == NULL) { - ent = enc_table->additional_list = ALLOC_N(struct rb_encoding_entry, add_size); - } - else { - ent = REALLOC_N(enc_table->additional_list, struct rb_encoding_entry, add_size); - } - - memset(ent + enc_table->additional_list_size, 0, sizeof(*ent)*(add_size - enc_table->additional_list_size)); - enc_table->additional_list = ent; - enc_table->additional_list_size = add_size; - } - } - - return newsize; -} - -static struct rb_encoding_entry * -enc_entry_at(struct enc_table *enc_table, int index) -{ - if (LIKELY(index < DEFAULT_ENCODING_LIST_CAPA)) { - return &enc_table->default_list[index]; - } - else { - struct rb_encoding_entry *e; - GLOBAL_ENC_TABLE_EVAL(enc_table, - e = &enc_table->additional_list[index - DEFAULT_ENCODING_LIST_CAPA]); - return e; - } + if (enc_table->size >= newsize) return newsize; + newsize = (newsize + 7) / 8 * 8; + ent = REALLOC_N(enc_table->list, struct rb_encoding_entry, newsize); + memset(ent + enc_table->size, 0, sizeof(*ent)*(newsize - enc_table->size)); + enc_table->list = ent; + enc_table->size = newsize; + return count; } static int enc_register_at(struct enc_table *enc_table, int index, const char *name, rb_encoding *base_encoding) { - struct rb_encoding_entry *ent = enc_entry_at(enc_table, index); + struct rb_encoding_entry *ent = &enc_table->list[index]; rb_raw_encoding *encoding; if (!valid_encoding_name_p(name)) return -1; @@ -441,18 +409,19 @@ static int enc_registered(struct enc_table *enc_table, const char *name); static rb_encoding * enc_from_index(struct enc_table *enc_table, int index) { - // do not need a lock - if (UNLIKELY(index < 0 || enc_table->count <= (index &= ENC_INDEX_MASK))) { return 0; } - return enc_entry_at(enc_table, index)->enc; + return enc_table->list[index].enc; } rb_encoding * rb_enc_from_index(int index) { - return enc_from_index(&global_enc_table, index); + rb_encoding *enc; + GLOBAL_ENC_TABLE_EVAL(enc_table, + enc = enc_from_index(enc_table, index)); + return enc; } int @@ -491,7 +460,7 @@ enc_registered(struct enc_table *enc_table, const char *name) st_data_t idx = 0; if (!name) return -1; - if (!enc_table->names) return -1; + if (!enc_table->list) return -1; if (st_lookup(enc_table->names, (st_data_t)name, &idx)) { return (int)idx; } @@ -523,9 +492,9 @@ enc_check_duplication(struct enc_table *enc_table, const char *name) static rb_encoding* set_base_encoding(struct enc_table *enc_table, int index, rb_encoding *base) { - struct rb_encoding_entry *entry = enc_entry_at(enc_table, index); - rb_encoding *enc = entry->enc; - entry->base = base; + rb_encoding *enc = enc_table->list[index].enc; + + enc_table->list[index].base = base; if (ENC_DUMMY_P(base)) ENC_SET_DUMMY((rb_raw_encoding *)enc); return enc; } @@ -552,7 +521,11 @@ rb_enc_set_base(const char *name, const char *orig) int rb_enc_set_dummy(int index) { - rb_encoding *enc = rb_enc_from_index(index); + rb_encoding *enc; + + GLOBAL_ENC_TABLE_EVAL(enc_table, + enc = enc_table->list[index].enc); + ENC_SET_DUMMY((rb_raw_encoding *)enc); return index; } @@ -642,10 +615,14 @@ rb_define_dummy_encoding(const char *name) { int index; - GLOBAL_ENC_TABLE_EVAL(enc_table, - index = enc_replicate(enc_table, name, rb_ascii8bit_encoding())); - rb_encoding *enc = rb_enc_from_index(index); - ENC_SET_DUMMY((rb_raw_encoding *)enc); + GLOBAL_ENC_TABLE_ENTER(enc_table); + { + index = enc_replicate(enc_table, name, rb_ascii8bit_encoding()); + rb_encoding *enc = enc_table->list[index].enc; + ENC_SET_DUMMY((rb_raw_encoding *)enc); + } + GLOBAL_ENC_TABLE_LEAVE(); + return index; } @@ -653,12 +630,17 @@ int rb_encdb_dummy(const char *name) { int index; - GLOBAL_ENC_TABLE_EVAL(enc_table, - index = enc_replicate_with_index(enc_table, name, - rb_ascii8bit_encoding(), - enc_registered(enc_table, name))); - rb_encoding *enc = rb_enc_from_index(index); - ENC_SET_DUMMY((rb_raw_encoding *)enc); + + GLOBAL_ENC_TABLE_ENTER(enc_table); + { + index = enc_replicate_with_index(enc_table, name, + rb_ascii8bit_encoding(), + enc_registered(enc_table, name)); + rb_encoding *enc = enc_table->list[index].enc; + ENC_SET_DUMMY((rb_raw_encoding *)enc); + } + GLOBAL_ENC_TABLE_LEAVE(); + return index; } @@ -788,10 +770,9 @@ rb_enc_init(struct enc_table *enc_table) ENC_REGISTER(ASCII); ENC_REGISTER(UTF_8); ENC_REGISTER(US_ASCII); - - global_enc_ascii = enc_table->default_list[ENCINDEX_ASCII].enc; - global_enc_utf_8 = enc_table->default_list[ENCINDEX_UTF_8].enc; - global_enc_us_ascii = enc_table->default_list[ENCINDEX_US_ASCII].enc; + global_enc_ascii = enc_table->list[ENCINDEX_ASCII].enc; + global_enc_utf_8 = enc_table->list[ENCINDEX_UTF_8].enc; + global_enc_us_ascii = enc_table->list[ENCINDEX_US_ASCII].enc; #undef ENC_REGISTER #define ENCDB_REGISTER(name, enc) enc_register_at(enc_table, ENCINDEX_##enc, name, NULL) ENCDB_REGISTER("UTF-16BE", UTF_16BE); @@ -847,7 +828,7 @@ load_encoding(const char *name) else if ((idx = enc_registered(enc_table, name)) < 0) { idx = -1; } - else if (enc_autoload_p(enc_from_index(enc_table, idx))) { + else if (enc_autoload_p(enc_table->list[idx].enc)) { idx = -1; } } @@ -859,13 +840,13 @@ load_encoding(const char *name) static int enc_autoload_body(struct enc_table *enc_table, rb_encoding *enc) { - rb_encoding *base = enc_entry_at(enc_table, ENC_TO_ENCINDEX(enc))->base; + rb_encoding *base = enc_table->list[ENC_TO_ENCINDEX(enc)].base; if (base) { int i = 0; do { if (i >= enc_table->count) return -1; - } while (enc_from_index(enc_table, i) != base && (++i, 1)); + } while (enc_table->list[i].enc != base && (++i, 1)); if (enc_autoload_p(base)) { if (enc_autoload(base) < 0) return -1; } @@ -2207,7 +2188,7 @@ Init_Encoding(void) rb_gc_register_mark_object(list); for (i = 0; i < enc_table->count; ++i) { - rb_ary_push(list, enc_new(enc_from_index(enc_table, i))); + rb_ary_push(list, enc_new(enc_table->list[i].enc)); } rb_marshal_define_compat(rb_cEncoding, Qnil, 0, enc_m_loader);