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References: <20110127104643.44D5723889F7@eris.apache.org>
Date: Thu, 27 Jan 2011 12:09:51 +0100
Message-ID: <AANLkTimChLDgctutf8YTDnZ70-OyMxD-h6a3JFfz-nrB@mail.gmail.com>
Subject: Re: svn commit: r1064076 -
 /couchdb/trunk/src/couchdb/couch_auth_cache.erl
From: Benoit Chesneau <bchesneau@gmail.com>
To: dev@couchdb.apache.org
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I think we could remove the uses of lists call and just use pattern
matching here. I attached a patch that is doing that. Also I added a
guard in case there is no member items in the cache.

- beno=EEt

---
 src/couchdb/couch_auth_cache.erl |   25 +++++++++++++++----------
 1 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/src/couchdb/couch_auth_cache.erl b/src/couchdb/couch_auth_cach=
e.erl
index 033e160..9bd3450 100644
--- a/src/couchdb/couch_auth_cache.erl
+++ b/src/couchdb/couch_auth_cache.erl
@@ -169,15 +169,7 @@ handle_call({new_max_cache_size, NewSize},
     {reply, ok, State#state{max_cache_size =3D NewSize}};

 handle_call({new_max_cache_size, NewSize}, _From, State) ->
-    lists:foreach(
-        fun(_) ->
-            LruTime =3D ets:last(?BY_ATIME),
-            [{LruTime, UserName}] =3D ets:lookup(?BY_ATIME, LruTime),
-            true =3D ets:delete(?BY_ATIME, LruTime),
-            true =3D ets:delete(?BY_USER, UserName)
-        end,
-        lists:seq(1, State#state.cache_size - NewSize)
-    ),
+    free_mru_cache_entries(State#state.cache_size - NewSize),
     {reply, ok, State#state{max_cache_size =3D NewSize, cache_size =3D New=
Size}};

 handle_call({fetch, UserName}, _From, State) ->
@@ -223,7 +215,7 @@ terminate(_Reason, #state{db_notifier =3D Notifier}) ->

 code_change(_OldVsn, State, _Extra) ->
     {ok, State}.
-
+

 clear_cache(State) ->
     exec_if_auth_db(fun(AuthDb) -> catch couch_db:close(AuthDb) end),
@@ -243,6 +235,19 @@ add_cache_entry(UserName, Credentials, ATime, State) -=
>
     true =3D ets:insert(?BY_USER, {UserName, {Credentials, ATime}}),
     State#state{cache_size =3D couch_util:get_value(size, ets:info(?BY_USE=
R))}.

+free_mru_cache_entries(1) ->
+    ok;
+free_mru_cache_entries(Count) ->
+    case ets:last(?BY_ATIME) of
+    '$end_of_table' ->
+        ok;
+    LruTime ->
+        [{LruTime, UserName}] =3D ets:lookup(?BY_ATIME, LruTime),
+        true =3D ets:delete(?BY_ATIME, LruTime),
+        true =3D ets:delete(?BY_USER, UserName),
+        free_mru_cache_entries(Count-1)
+    end.
+

 free_mru_cache_entry() ->
     case ets:last(?BY_ATIME) of
--=20
1.7.3.4


On Thu, Jan 27, 2011 at 11:46 AM,  <fdmanana@apache.org> wrote:
> Author: fdmanana
> Date: Thu Jan 27 10:46:42 2011
> New Revision: 1064076
>
> URL: http://svn.apache.org/viewvc?rev=3D1064076&view=3Drev
> Log:
> Trivial small refactoring
>
> Shortening the code by using multiple function clauses.
>
> Modified:
> =A0 =A0couchdb/trunk/src/couchdb/couch_auth_cache.erl
>
> Modified: couchdb/trunk/src/couchdb/couch_auth_cache.erl
> URL: http://svn.apache.org/viewvc/couchdb/trunk/src/couchdb/couch_auth_ca=
che.erl?rev=3D1064076&r1=3D1064075&r2=3D1064076&view=3Ddiff
> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D
> --- couchdb/trunk/src/couchdb/couch_auth_cache.erl (original)
> +++ couchdb/trunk/src/couchdb/couch_auth_cache.erl Thu Jan 27 10:46:42 20=
11
> @@ -110,11 +110,8 @@ init(_) ->
> =A0 =A0 ok =3D couch_config:register(
> =A0 =A0 =A0 =A0 fun("couch_httpd_auth", "auth_cache_size", SizeList) ->
> =A0 =A0 =A0 =A0 =A0 =A0 Size =3D list_to_integer(SizeList),
> - =A0 =A0 =A0 =A0 =A0 =A0ok =3D gen_server:call(?MODULE, {new_max_cache_s=
ize, Size}, infinity)
> - =A0 =A0 =A0 =A0end
> - =A0 =A0),
> - =A0 =A0ok =3D couch_config:register(
> - =A0 =A0 =A0 =A0fun("couch_httpd_auth", "authentication_db", DbName) ->
> + =A0 =A0 =A0 =A0 =A0 =A0ok =3D gen_server:call(?MODULE, {new_max_cache_s=
ize, Size}, infinity);
> + =A0 =A0 =A0 =A0("couch_httpd_auth", "authentication_db", DbName) ->
> =A0 =A0 =A0 =A0 =A0 =A0 ok =3D gen_server:call(?MODULE, {new_auth_db, ?l2=
b(DbName)}, infinity)
> =A0 =A0 =A0 =A0 end
> =A0 =A0 ),
> @@ -167,26 +164,21 @@ handle_call(auth_db_compacted, _From, St
> =A0 =A0 ),
> =A0 =A0 {reply, ok, State};
>
> +handle_call({new_max_cache_size, NewSize},
> + =A0 =A0 =A0 =A0_From, #state{cache_size =3D Size} =3D State) when NewSi=
ze >=3D Size ->
> + =A0 =A0{reply, ok, State#state{max_cache_size =3D NewSize}};
> +
> =A0handle_call({new_max_cache_size, NewSize}, _From, State) ->
> - =A0 =A0case NewSize >=3D State#state.cache_size of
> - =A0 =A0true ->
> - =A0 =A0 =A0 =A0ok;
> - =A0 =A0false ->
> - =A0 =A0 =A0 =A0lists:foreach(
> - =A0 =A0 =A0 =A0 =A0 =A0fun(_) ->
> - =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0LruTime =3D ets:last(?BY_ATIME),
> - =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0[{LruTime, UserName}] =3D ets:lookup(?BY=
_ATIME, LruTime),
> - =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0true =3D ets:delete(?BY_ATIME, LruTime),
> - =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0true =3D ets:delete(?BY_USER, UserName)
> - =A0 =A0 =A0 =A0 =A0 =A0end,
> - =A0 =A0 =A0 =A0 =A0 =A0lists:seq(1, State#state.cache_size - NewSize)
> - =A0 =A0 =A0 =A0)
> - =A0 =A0end,
> - =A0 =A0NewState =3D State#state{
> - =A0 =A0 =A0 =A0max_cache_size =3D NewSize,
> - =A0 =A0 =A0 =A0cache_size =3D lists:min([NewSize, State#state.cache_siz=
e])
> - =A0 =A0},
> - =A0 =A0{reply, ok, NewState};
> + =A0 =A0lists:foreach(
> + =A0 =A0 =A0 =A0fun(_) ->
> + =A0 =A0 =A0 =A0 =A0 =A0LruTime =3D ets:last(?BY_ATIME),
> + =A0 =A0 =A0 =A0 =A0 =A0[{LruTime, UserName}] =3D ets:lookup(?BY_ATIME, =
LruTime),
> + =A0 =A0 =A0 =A0 =A0 =A0true =3D ets:delete(?BY_ATIME, LruTime),
> + =A0 =A0 =A0 =A0 =A0 =A0true =3D ets:delete(?BY_USER, UserName)
> + =A0 =A0 =A0 =A0end,
> + =A0 =A0 =A0 =A0lists:seq(1, State#state.cache_size - NewSize)
> + =A0 =A0),
> + =A0 =A0{reply, ok, State#state{max_cache_size =3D NewSize, cache_size =
=3D NewSize}};
>
> =A0handle_call({fetch, UserName}, _From, State) ->
> =A0 =A0 {Credentials, NewState} =3D case ets:lookup(?BY_USER, UserName) o=
f
>
>
>