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-rw-r--r--lib/stdlib/doc/src/ets.xml20
-rw-r--r--lib/stdlib/test/ets_SUITE.erl90
2 files changed, 58 insertions, 52 deletions
diff --git a/lib/stdlib/doc/src/ets.xml b/lib/stdlib/doc/src/ets.xml
index 3e9ad89b26..29d22ffae5 100644
--- a/lib/stdlib/doc/src/ets.xml
+++ b/lib/stdlib/doc/src/ets.xml
@@ -1492,25 +1492,21 @@ is_integer(X), is_integer(Y), X + Y < 4711]]></code>
<func>
<name name="select_replace" arity="2"/>
- <fsummary>Match the objects in an ETS table against a match_spec and
- replaces matching objects with the match_spec result</fsummary>
+ <fsummary>Match and replace objects atomically in an ETS table</fsummary>
<desc>
<warning>
<p>For the moment, due to performance and semantic constraints,
tables of type <c>bag</c> are not yet supported.</p>
</warning>
<p>Matches the objects in the table <c><anno>Tab</anno></c> using a
- <seealso marker="#match_spec">match_spec</seealso>. If the
- an object is matched, and the match_spec result is an object with the
- same key, the existing object is replaced with the match_spec result.
- For any other result from the match_spec the object is kept
- unchanged.</p>
- <p>The function returns the number of objects actually
- replaced in the table.</p>
+ <seealso marker="#match_spec">match specification</seealso>. If the
+ an object is matched, the existing object is replaced with
+ the match specificatoin result.</p>
+ <p>The function returns the total number of replaced objects.</p>
<note>
- <p>The <c>match_spec</c> has to return an object with the same key if
- the object is to be replaced. No other return value will get the
- object replaced.</p>
+ <p>If there's a risk a match specification might return
+ a tuple with a different key, the whole operation will fail
+ with <c>badarg</c>.</p>
</note>
</desc>
</func>
diff --git a/lib/stdlib/test/ets_SUITE.erl b/lib/stdlib/test/ets_SUITE.erl
index fed3c3ac61..68d73e78b0 100644
--- a/lib/stdlib/test/ets_SUITE.erl
+++ b/lib/stdlib/test/ets_SUITE.erl
@@ -1147,36 +1147,50 @@ t_select_replace(Config) when is_list(Config) ->
10000 = ets:select_delete(Table, [{'_',[],[true]}]);
(Table, TableType) ->
- % Replacements are differently-sized objects
- MatchSpec1_A = [{{'$1','$2'},
- [{'<', {'rem', '$1', 5}, 2}],
- [{{'$1', [$x | '$2'], stuff}}]}],
- MatchSpec1_B = [{{'$1','$2','_'},
- [],
- [{{'$1','$2'}}]}],
- 4000 = ets:select_replace(Table, MatchSpec1_A),
- 4000 = ets:select_replace(Table, MatchSpec1_B),
+ % Invalid replacement doesn't keep the key
+ MatchSpec1 = [{{'$1', '$2'},
+ [{'=:=', {'band', '$1', 2#11}, 2#11},
+ {'=/=', {'hd', '$2'}, $x}],
+ [{{'$2', '$1'}}]}],
+ {'EXIT',{badarg,_}} = (catch ets:select_replace(Table, MatchSpec1)),
- % Replacement changes key to float equivalent
+ % Invalid replacement doesn't keep the key (even though it would be the same value)
MatchSpec2 = [{{'$1', '$2'},
+ [{'=:=', {'band', '$1', 2#11}, 2#11}],
+ [{{{'+', '$1', 0}, '$2'}}]},
+ {{'$1', '$2'},
+ [{'=/=', {'band', '$1', 2#11}, 2#11}],
+ [{{{'-', '$1', 0}, '$2'}}]}],
+ {'EXIT',{badarg,_}} = (catch ets:select_replace(Table, MatchSpec2)),
+
+ % Invalid replacement changes key to float equivalent
+ MatchSpec3 = [{{'$1', '$2'},
[{'=:=', {'band', '$1', 2#11}, 2#11},
{'=/=', {'hd', '$2'}, $x}],
[{{{'*', '$1', 1.0}, '$2'}}]}],
- case TableType of
- ordered_set -> 1500 = ets:select_replace(Table, MatchSpec2);
- set -> 0 = ets:select_replace(Table, MatchSpec2);
- duplicate_bag -> 0 = ets:select_replace(Table, MatchSpec2)
- end,
+ {'EXIT',{badarg,_}} = (catch ets:select_replace(Table, MatchSpec3)),
- % Replacement is an equal object
- MatchSpec3 = [{{'$1', '$2'},
+ % Replacements are differently-sized tuples
+ MatchSpec4_A = [{{'$1','$2'},
+ [{'<', {'rem', '$1', 5}, 2}],
+ [{{'$1', [$x | '$2'], stuff}}]}],
+ MatchSpec4_B = [{{'$1','$2','_'},
+ [],
+ [{{'$1','$2'}}]}],
+ 4000 = ets:select_replace(Table, MatchSpec4_A),
+ 4000 = ets:select_replace(Table, MatchSpec4_B),
+
+ % Replacement is the same tuple
+ MatchSpec5 = [{{'$1', '$2'},
+ [{'>', {'rem', '$1', 5}, 3}],
+ ['$_']}],
+ 2000 = ets:select_replace(Table, MatchSpec5),
+
+ % Replacement reconstructs an equal tuple
+ MatchSpec6 = [{{'$1', '$2'},
[{'>', {'rem', '$1', 5}, 3}],
[{{'$1', '$2'}}]}],
- case TableType of
- ordered_set -> 1500 = ets:select_replace(Table, MatchSpec3);
- set -> 2000 = ets:select_replace(Table, MatchSpec3);
- duplicate_bag -> 2000 = ets:select_replace(Table, MatchSpec3)
- end,
+ 2000 = ets:select_replace(Table, MatchSpec6),
check(Table,
fun ({N, [$x, C | _]}) when ((N rem 5) < 2) -> (C >= $0) andalso (C =< $9);
@@ -1187,47 +1201,43 @@ t_select_replace(Config) when is_list(Config) ->
10000),
% Replace unbound range (>)
- MatchSpec4 = [{{'$1', '$2'},
+ MatchSpec7 = [{{'$1', '$2'},
[{'>', '$1', 7000}],
[{{'$1', {{gt_range, '$2'}}}}]}],
- case TableType of
- ordered_set -> 3000 = ets:select_replace(Table, MatchSpec4);
- set -> 3000 = ets:select_replace(Table, MatchSpec4);
- duplicate_bag -> 3000 = ets:select_replace(Table, MatchSpec4)
- end,
+ 3000 = ets:select_replace(Table, MatchSpec7),
% Replace unbound range (<)
- MatchSpec5 = [{{'$1', '$2'},
+ MatchSpec8 = [{{'$1', '$2'},
[{'<', '$1', 3000}],
[{{'$1', {{le_range, '$2'}}}}]}],
case TableType of
- ordered_set -> 2999 = ets:select_replace(Table, MatchSpec5);
- set -> 2999 = ets:select_replace(Table, MatchSpec5);
- duplicate_bag -> 2998 = ets:select_replace(Table, MatchSpec5)
+ ordered_set -> 2999 = ets:select_replace(Table, MatchSpec8);
+ set -> 2999 = ets:select_replace(Table, MatchSpec8);
+ duplicate_bag -> 2998 = ets:select_replace(Table, MatchSpec8)
end,
% Replace bound range
- MatchSpec6 = [{{'$1', '$2'},
+ MatchSpec9 = [{{'$1', '$2'},
[{'>=', '$1', 3001},
{'<', '$1', 7000}],
[{{'$1', {{range, '$2'}}}}]}],
case TableType of
- ordered_set -> 3999 = ets:select_replace(Table, MatchSpec6);
- set -> 3999 = ets:select_replace(Table, MatchSpec6);
- duplicate_bag -> 3998 = ets:select_replace(Table, MatchSpec6)
+ ordered_set -> 3999 = ets:select_replace(Table, MatchSpec9);
+ set -> 3999 = ets:select_replace(Table, MatchSpec9);
+ duplicate_bag -> 3998 = ets:select_replace(Table, MatchSpec9)
end,
% Replace particular keys
- MatchSpec7 = [{{'$1', '$2'},
+ MatchSpec10 = [{{'$1', '$2'},
[{'==', '$1', 3000}],
[{{'$1', {{specific1, '$2'}}}}]},
{{'$1', '$2'},
[{'==', '$1', 7000}],
[{{'$1', {{specific2, '$2'}}}}]}],
case TableType of
- ordered_set -> 2 = ets:select_replace(Table, MatchSpec7);
- set -> 2 = ets:select_replace(Table, MatchSpec7);
- duplicate_bag -> 4 = ets:select_replace(Table, MatchSpec7)
+ ordered_set -> 2 = ets:select_replace(Table, MatchSpec10);
+ set -> 2 = ets:select_replace(Table, MatchSpec10);
+ duplicate_bag -> 4 = ets:select_replace(Table, MatchSpec10)
end,
check(Table,
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-18 02:50:13 +0000