diff options
Diffstat (limited to 'erts/emulator/beam/erl_db_util.c')
| -rw-r--r-- | erts/emulator/beam/erl_db_util.c | 180 |
1 files changed, 178 insertions, 2 deletions
diff --git a/erts/emulator/beam/erl_db_util.c b/erts/emulator/beam/erl_db_util.c index 6f30b1d3dd..03cc11bdc4 100644 --- a/erts/emulator/beam/erl_db_util.c +++ b/erts/emulator/beam/erl_db_util.c @@ -1119,6 +1119,177 @@ error: return NULL; } +/* + * Compare a matching term 'a' with a constructing term 'b' for equality. + * + * Returns true if 'b' is guaranteed to always construct + * the same term as 'a' has matched. + */ +static int db_match_eq_body(Eterm a, Eterm b) +{ + DECLARE_ESTACK(s); + Uint arity; + Eterm *ap, *bp; + int const_mode = 0; + const Eterm CONST_MODE_OFF = THE_NON_VALUE; + + while (1) { + switch(b & _TAG_PRIMARY_MASK) { + case TAG_PRIMARY_LIST: + if (!is_list(a)) + return 0; + ESTACK_PUSH2(s, CDR(list_val(a)), CDR(list_val(b))); + a = CAR(list_val(a)); + b = CAR(list_val(b)); + continue; /* loop without pop */ + + case TAG_PRIMARY_BOXED: + if (is_tuple(b)) { + bp = tuple_val(b); + if (!const_mode) { + if (bp[0] == make_arityval(1) && is_tuple(bp[1])) { + b = bp[1]; /* double-tuple syntax */ + } + else if (bp[0] == make_arityval(2) && bp[1] == am_const) { + ESTACK_PUSH(s, CONST_MODE_OFF); + const_mode = 1; /* {const, term()} syntax */ + b = bp[2]; + continue; /* loop without pop */ + } + else + return 0; /* function call or invalid tuple syntax */ + } + if (!is_tuple(a)) + return 0; + + ap = tuple_val(a); + bp = tuple_val(b); + if (ap[0] != bp[0]) + return 0; + arity = arityval(ap[0]); + if (arity > 0) { + a = *(++ap); + b = *(++bp); + while(--arity) { + ESTACK_PUSH2(s, *(++ap), *(++bp)); + } + continue; /* loop without pop */ + } + } + else if (is_map(b)) { + /* We don't know what other pairs the matched map may contain */ + return 0; + } + else if (!eq(a,b)) /* other boxed */ + return 0; + break; + + case TAG_PRIMARY_IMMED1: + if (a != b || a == am_Underscore || a == am_DollarDollar + || a == am_DollarUnderscore + || (const_mode && db_is_variable(a) >= 0)) { + + return 0; + } + break; + default: + erts_exit(ERTS_ABORT_EXIT, "db_compare: " + "Bad object on ESTACK: 0x%bex\n", b); + } + +pop_next: + if (ESTACK_ISEMPTY(s)) + break; /* done */ + + b = ESTACK_POP(s); + if (b == CONST_MODE_OFF) { + ASSERT(const_mode); + const_mode = 0; + goto pop_next; + } + a = ESTACK_POP(s); + } + + DESTROY_ESTACK(s); + return 1; +} + +/* This is used by select_replace */ +int db_match_keeps_key(int keypos, Eterm match, Eterm guard, Eterm body) +{ + Eterm match_key; + Eterm* body_list; + Eterm single_body_term; + Eterm* single_body_term_tpl; + Eterm single_body_subterm; + Eterm single_body_subterm_key; + Eterm* single_body_subterm_key_tpl; + + if (!is_list(body)) { + return 0; + } + + body_list = list_val(body); + if (CDR(body_list) != NIL) { + return 0; + } + + single_body_term = CAR(body_list); + if (single_body_term == am_DollarUnderscore) { + /* same tuple is returned */ + return 1; + } + + if (!is_tuple(single_body_term)) { + return 0; + } + + single_body_term_tpl = tuple_val(single_body_term); + if (arityval(*single_body_term_tpl) != 1) { + // not the 1-element tuple we're expecting + return 0; + } + + match_key = db_getkey(keypos, match); + if (!is_value(match_key)) { + // can't get key out of match + return 0; + } + + single_body_subterm = single_body_term_tpl[1]; + single_body_subterm_key = db_getkey(keypos, single_body_subterm); + if (!is_value(single_body_subterm_key)) { + // can't get key out of single body subterm + return 0; + } + + if (db_match_eq_body(match_key, single_body_subterm_key)) { + /* tuple with same key is returned */ + return 1; + } + + if (!is_tuple(single_body_subterm_key)) { + /* can't possibly be an element instruction */ + return 0; + } + + single_body_subterm_key_tpl = tuple_val(single_body_subterm_key); + if (arityval(*single_body_subterm_key_tpl) != 3) { + /* can't possibly be an element instruction */ + return 0; + } + + if (single_body_subterm_key_tpl[1] == am_element && + single_body_subterm_key_tpl[3] == am_DollarUnderscore && + single_body_subterm_key_tpl[2] == make_small(keypos)) + { + /* {element, KeyPos, '$_'} */ + return 1; + } + + return 0; +} + /* This is used when tracing */ Eterm erts_match_set_lint(Process *p, Eterm matchexpr) { return db_match_set_lint(p, matchexpr, DCOMP_TRACE); @@ -2172,7 +2343,7 @@ restart: } } else { - *esp = term; + *esp++ = term; } break; case matchPushArrayAsList: @@ -5161,6 +5332,7 @@ void db_free_tmp_uncompressed(DbTerm* obj) Eterm db_match_dbterm(DbTableCommon* tb, Process* c_p, Binary* bprog, int all, DbTerm* obj, Eterm** hpp, Uint extra) { + enum erts_pam_run_flags flags; Uint32 dummy; Eterm res; @@ -5168,9 +5340,13 @@ Eterm db_match_dbterm(DbTableCommon* tb, Process* c_p, Binary* bprog, obj = db_alloc_tmp_uncompressed(tb, obj); } + flags = (hpp ? + ERTS_PAM_COPY_RESULT | ERTS_PAM_CONTIGUOUS_TUPLE : + ERTS_PAM_TMP_RESULT | ERTS_PAM_CONTIGUOUS_TUPLE); + res = db_prog_match(c_p, c_p, bprog, make_tuple(obj->tpl), NULL, 0, - ERTS_PAM_COPY_RESULT|ERTS_PAM_CONTIGUOUS_TUPLE, &dummy); + flags, &dummy); if (is_value(res) && hpp!=NULL) { *hpp = HAlloc(c_p, extra); |