diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/stdlib/doc/src/ets.xml | 31 | ||||
| -rw-r--r-- | lib/stdlib/src/ets.erl | 11 | ||||
| -rw-r--r-- | lib/stdlib/test/ets_SUITE.erl | 35 |
3 files changed, 70 insertions, 7 deletions
diff --git a/lib/stdlib/doc/src/ets.xml b/lib/stdlib/doc/src/ets.xml index 1b31a1ec9d..305376a425 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> @@ -1074,10 +1079,13 @@ ets:select(Table, MatchSpec),</code> </item> <tag><c>named_table</c></tag> <item> - <p>If this option is present, name <c><anno>Name</anno></c> is - associated with the table identifier. The name can then - be used instead of the table identifier in subsequent - operations.</p> + <p>If this option is present, the table is registered under its + <c><anno>Name</anno></c> which can then be used instead of the + table identifier in subsequent operations.</p> + <p>The function will also return the <c><anno>Name</anno></c> + instead of the table identifier. To get the table identifier of a + named table, use + <seealso marker="#whereis/1"><c>whereis/1</c></seealso>.</p> </item> <tag><c>{keypos,<anno>Pos</anno>}</c></tag> <item> @@ -2037,6 +2045,21 @@ 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: |