Implement ets:take/2

This new ETS BIF returns and deletes objects from tables.

3 files changed, 63 insertions, 0 deletions

diff --git a/lib/stdlib/doc/src/ets.xml b/lib/stdlib/doc/src/ets.xml
index 3df24bf688..ef08f3c0cc 100644
--- a/lib/stdlib/doc/src/ets.xml
+++ b/lib/stdlib/doc/src/ets.xml
@@ -1587,6 +1587,21 @@ true</pre>
       </desc>
     </func>
     <func>
+      <name name="take" arity="2"/>
+      <fsummary>Return and remove all objects with a given key from an ETS
+        table.</fsummary>
+      <desc>
+        <p>Returns a list of all objects with the key <c><anno>Key</anno></c> in
+          the table <c><anno>Tab</anno></c> and removes.</p>
+        <p>The given <c><anno>Key</anno></c> is used to identify the object by
+          either <em>comparing equal</em> the key of an object in an
+          <c>ordered_set</c> table, or <em>matching</em> in other types of
+          tables (see <seealso marker="#lookup/2">lookup/2</seealso> and
+          <seealso marker="#new/2">new/2</seealso> for details on the
+          difference).</p>
+      </desc>
+    </func>
+    <func>
       <name name="to_dets" arity="2"/>
       <fsummary>Fill a Dets table with objects from an ETS table.</fsummary>
       <desc>
diff --git a/lib/stdlib/src/ets.erl b/lib/stdlib/src/ets.erl
index 42b11a97e2..902ccbe11a 100644
--- a/lib/stdlib/src/ets.erl
+++ b/lib/stdlib/src/ets.erl
@@ -71,6 +71,7 @@
          rename/2, safe_fixtable/2, select/1, select/2, select/3,
          select_count/2, select_delete/2, select_reverse/1,
          select_reverse/2, select_reverse/3, setopts/2, slot/2,
+         take/2,
          update_counter/3, update_element/3]).
 
 -spec all() -> [Tab] when
@@ -400,6 +401,14 @@ setopts(_, _) ->
 slot(_, _) ->
     erlang:nif_error(undef).
 
+-spec take(Tab, Key) -> [Object] when
+      Tab :: tab(),
+      Key :: term(),
+      Object :: tuple().
+
+take(_, _) ->
+    erlang:nif_error(undef).
+
 -spec update_counter(Tab, Key, UpdateOp) -> Result when
       Tab :: tab(),
       Key :: term(),
diff --git a/lib/stdlib/test/ets_SUITE.erl b/lib/stdlib/test/ets_SUITE.erl
index 8dc8b2c291..2674f6886f 100644
--- a/lib/stdlib/test/ets_SUITE.erl
+++ b/lib/stdlib/test/ets_SUITE.erl
@@ -77,6 +77,7 @@
 -export([otp_10182/1]).
 -export([ets_all/1]).
 -export([memory_check_summary/1]).
+-export([take/1]).
 
 -export([init_per_testcase/2, end_per_testcase/2]).
 %% Convenience for manual testing
@@ -153,6 +154,7 @@ all() ->
      otp_9932,
      otp_9423,
      ets_all,
+     take,
      
      memory_check_summary]. % MUST BE LAST
 
@@ -5582,6 +5584,43 @@ ets_all_run() ->
     ets_all_run().
     
 
+take(Config) when is_list(Config) ->
+    %% Simple test for set tables.
+    T1 = ets_new(a, [set]),
+    [] = ets:take(T1, foo),
+    ets:insert(T1, {foo,bar}),
+    [] = ets:take(T1, bar),
+    [{foo,bar}] = ets:take(T1, foo),
+    [] = ets:tab2list(T1),
+    %% Non-immediate key.
+    ets:insert(T1, {{'not',<<"immediate">>},ok}),
+    [{{'not',<<"immediate">>},ok}] = ets:take(T1, {'not',<<"immediate">>}),
+    %% Same with ordered tables.
+    T2 = ets_new(b, [ordered_set]),
+    [] = ets:take(T2, foo),
+    ets:insert(T2, {foo,bar}),
+    [] = ets:take(T2, bar),
+    [{foo,bar}] = ets:take(T2, foo),
+    [] = ets:tab2list(T2),
+    ets:insert(T2, {{'not',<<"immediate">>},ok}),
+    [{{'not',<<"immediate">>},ok}] = ets:take(T2, {'not',<<"immediate">>}),
+    %% Arithmetically-equal keys.
+    ets:insert(T2, [{1.0,float},{2,integer}]),
+    [{1.0,float}] = ets:take(T2, 1),
+    [{2,integer}] = ets:take(T2, 2.0),
+    [] = ets:tab2list(T2),
+    %% Same with bag.
+    T3 = ets_new(c, [bag]),
+    ets:insert(T3, [{1,1},{1,2},{3,3}]),
+    [{1,1},{1,2}] = ets:take(T3, 1),
+    [{3,3}] = ets:take(T3, 3),
+    [] = ets:tab2list(T3),
+    ets:delete(T1),
+    ets:delete(T2),
+    ets:delete(T3),
+    ok.
+
+
 %
 % Utility functions:
 %