diff options
| -rw-r--r-- | erts/emulator/beam/bif.tab | 1 | ||||
| -rw-r--r-- | erts/emulator/beam/erl_db.c | 28 | ||||
| -rw-r--r-- | lib/stdlib/doc/src/ets.xml | 20 | ||||
| -rw-r--r-- | lib/stdlib/src/ets.erl | 11 | ||||
| -rw-r--r-- | lib/stdlib/test/ets_SUITE.erl | 35 |
5 files changed, 91 insertions, 4 deletions
diff --git a/erts/emulator/beam/bif.tab b/erts/emulator/beam/bif.tab index c0d5e8ce74..b5725e4185 100644 --- a/erts/emulator/beam/bif.tab +++ b/erts/emulator/beam/bif.tab @@ -696,3 +696,4 @@ bif erlang:iolist_to_iovec/1 bif erts_internal:new_connection/1 bif erts_internal:abort_connection/2 bif erts_internal:map_next/3 +bif ets:whereis/1 diff --git a/erts/emulator/beam/erl_db.c b/erts/emulator/beam/erl_db.c index 3ba0886464..1ab1c4a363 100644 --- a/erts/emulator/beam/erl_db.c +++ b/erts/emulator/beam/erl_db.c @@ -1753,6 +1753,28 @@ BIF_RETTYPE ets_new_2(BIF_ALIST_2) BIF_RET(ret); } +/* +** Retrieves the tid() of a named ets table. +*/ +BIF_RETTYPE ets_whereis_1(BIF_ALIST_1) +{ + DbTable* tb; + Eterm res; + + if (is_not_atom(BIF_ARG_1)) { + BIF_ERROR(BIF_P, BADARG); + } + + if ((tb = db_get_table(BIF_P, BIF_ARG_1, DB_INFO, LCK_READ)) == NULL) { + BIF_RET(am_undefined); + } + + res = make_tid(BIF_P, tb); + db_unlock(tb, LCK_READ); + + BIF_RET(res); +} + /* ** The lookup BIF */ @@ -3126,7 +3148,8 @@ BIF_RETTYPE ets_info_1(BIF_ALIST_1) static Eterm fields[] = {am_protection, am_keypos, am_type, am_named_table, am_node, am_size, am_name, am_heir, am_owner, am_memory, am_compressed, am_write_concurrency, - am_read_concurrency}; + am_read_concurrency, + am_id}; Eterm results[sizeof(fields)/sizeof(Eterm)]; DbTable* tb; Eterm res; @@ -4016,7 +4039,10 @@ static Eterm table_info(Process* p, DbTable* tb, Eterm What) ret = is_table_named(tb) ? am_true : am_false; } else if (What == am_compressed) { ret = tb->common.compress ? am_true : am_false; + } else if (What == am_id) { + ret = make_tid(p, tb); } + /* * For debugging purposes */ diff --git a/lib/stdlib/doc/src/ets.xml b/lib/stdlib/doc/src/ets.xml index 1b31a1ec9d..b616e97714 100644 --- a/lib/stdlib/doc/src/ets.xml +++ b/lib/stdlib/doc/src/ets.xml @@ -487,6 +487,11 @@ Error: fun containing local Erlang function calls <p>The pid of the heir of the table, or <c>none</c> if no heir is set.</p> </item> + <tag><c>{id,</c><seealso marker="#type-tid"> + <c>tid()</c></seealso><c>}</c></tag> + <item> + <p>The table identifier.</p> + </item> <tag><c>{keypos, integer() >= 1}</c></tag> <item> <p>The key position.</p> @@ -2037,6 +2042,21 @@ true</pre> </list> </desc> </func> + + <func> + <name name="whereis" arity="1"/> + <fsummary>Retrieves the tid() of a named table.</fsummary> + <desc> + <p>This function returns the + <seealso marker="#type-tid"><c>tid()</c></seealso> of the named table + identified by <c><anno>TableName</anno></c>, or <c>undefined</c> if + no such table exists. The <c>tid()</c> can be used in place of the + table name in all operations, which is slightly faster since the name + does not have to be resolved on each call.</p> + <p>If the table is deleted, the <c>tid()</c> will be invalid even if + another named table is created with the same name.</p> + </desc> + </func> </funcs> </erlref> diff --git a/lib/stdlib/src/ets.erl b/lib/stdlib/src/ets.erl index 039ab45868..6a559f0be5 100644 --- a/lib/stdlib/src/ets.erl +++ b/lib/stdlib/src/ets.erl @@ -73,7 +73,8 @@ select_count/2, select_delete/2, select_replace/2, select_reverse/1, select_reverse/2, select_reverse/3, setopts/2, slot/2, take/2, - update_counter/3, update_counter/4, update_element/3]). + update_counter/3, update_counter/4, update_element/3, + whereis/1]). %% internal exports -export([internal_request_all/0]). @@ -145,6 +146,7 @@ give_away(_, _, _) -> InfoList :: [InfoTuple], InfoTuple :: {compressed, boolean()} | {heir, pid() | none} + | {id, tid()} | {keypos, pos_integer()} | {memory, non_neg_integer()} | {name, atom()} @@ -162,7 +164,7 @@ info(_) -> -spec info(Tab, Item) -> Value | undefined when Tab :: tab(), - Item :: compressed | fixed | heir | keypos | memory + Item :: compressed | fixed | heir | id | keypos | memory | name | named_table | node | owner | protection | safe_fixed | safe_fixed_monotonic_time | size | stats | type | write_concurrency | read_concurrency, @@ -512,6 +514,11 @@ update_counter(_, _, _, _) -> update_element(_, _, _) -> erlang:nif_error(undef). +-spec whereis(TableName) -> tid() | undefined when + TableName :: atom(). +whereis(_) -> + erlang:nif_error(undef). + %%% End of BIFs -opaque comp_match_spec() :: reference(). diff --git a/lib/stdlib/test/ets_SUITE.erl b/lib/stdlib/test/ets_SUITE.erl index 0cfb1b5516..8b651f4b43 100644 --- a/lib/stdlib/test/ets_SUITE.erl +++ b/lib/stdlib/test/ets_SUITE.erl @@ -78,6 +78,7 @@ -export([ets_all/1]). -export([massive_ets_all/1]). -export([take/1]). +-export([whereis_table/1]). -export([init_per_testcase/2, end_per_testcase/2]). %% Convenience for manual testing @@ -137,7 +138,8 @@ all() -> otp_9423, ets_all, massive_ets_all, - take]. + take, + whereis_table]. groups() -> [{new, [], @@ -4099,6 +4101,7 @@ info_do(Opts) -> {value, {keypos, 2}} = lists:keysearch(keypos, 1, Res), {value, {protection, protected}} = lists:keysearch(protection, 1, Res), + {value, {id, Tab}} = lists:keysearch(id, 1, Res), true = ets:delete(Tab), undefined = ets:info(non_existing_table_xxyy), undefined = ets:info(non_existing_table_xxyy,type), @@ -5892,6 +5895,36 @@ take(Config) when is_list(Config) -> ets:delete(T3), ok. +whereis_table(Config) when is_list(Config) -> + %% Do we return 'undefined' when the named table doesn't exist? + undefined = ets:whereis(whereis_test), + + %% Does the tid() refer to the same table as the name? + whereis_test = ets:new(whereis_test, [named_table]), + Tid = ets:whereis(whereis_test), + + ets:insert(whereis_test, [{hello}, {there}]), + + [[{hello}],[{there}]] = ets:match(whereis_test, '$1'), + [[{hello}],[{there}]] = ets:match(Tid, '$1'), + + true = ets:delete_all_objects(Tid), + + [] = ets:match(whereis_test, '$1'), + [] = ets:match(Tid, '$1'), + + %% Does the name disappear when deleted through the tid()? + true = ets:delete(Tid), + undefined = ets:info(whereis_test), + {'EXIT',{badarg, _}} = (catch ets:match(whereis_test, '$1')), + + %% Is the old tid() broken when the table is re-created with the same + %% name? + whereis_test = ets:new(whereis_test, [named_table]), + [] = ets:match(whereis_test, '$1'), + {'EXIT',{badarg, _}} = (catch ets:match(Tid, '$1')), + + ok. %% %% Utility functions: |