From 7ef7142f72b59091f73fd4d23270b9399fd07789 Mon Sep 17 00:00:00 2001
From: Tobias Schlager <tobias.schlager@vier.ai>
Date: Fri, 13 Sep 2024 09:12:30 +0200
Subject: [PATCH] Restore compatibility with older OTP releases

Support is ensured for OTP-24 but it should also still work for older
releases (not guaranteed).
---
 .github/workflows/test.yml |  2 +-
 README.md                  |  4 +++-
 src/eipmi.erl              | 20 +++++++++-----------
 3 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 78093d8..319e2a2 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        otp: [25, 26, 27]
+        otp: [24, 25, 26, 27]
     container:
       image: erlang:${{ matrix.otp }}
     steps:
diff --git a/README.md b/README.md
index 0003bb7..24aa594 100644
--- a/README.md
+++ b/README.md
@@ -227,7 +227,9 @@ History
 
 ### Master (4.0.1)
 
-Currently no difference to latest tag.
+* Enhance performance of session lookups (thanks to @IslandUsurper)
+* Drop (official) support for OTP releases older than 24.3 (currently it should
+  still work with older versions)
 
 ### Version 4.0.0
 
diff --git a/src/eipmi.erl b/src/eipmi.erl
index 74bd7dc..c5e3cd0 100644
--- a/src/eipmi.erl
+++ b/src/eipmi.erl
@@ -1,5 +1,5 @@
 %%%=============================================================================
-%%% Copyright (c) 2012-2019 Lindenbaum GmbH
+%%% Copyright (c) 2012-2024 Lindenbaum GmbH
 %%%
 %%% Permission to use, copy, modify, and/or distribute this software for any
 %%% purpose with or without fee is hereby granted, provided that the above
@@ -1145,10 +1145,8 @@ poll_sel(Session) ->
 poll_sel(Session = {session, Target, _}, Interval, Clear) when Interval > 0 ->
     Result =
         case ets:lookup(eipmi_sessions, {session, Target}) of
-            [{_, Pid, _}] ->
-                {ok, Pid};
-            [] ->
-                {error, no_session}
+            [{_, Pid, _}] -> {ok, Pid};
+            [] -> {error, no_session}
         end,
     poll_sel(Result, Session, Interval, Clear).
 poll_sel({ok, Pid}, Session, Interval, Clear) ->
@@ -1554,12 +1552,12 @@ stop(_State) -> ok.
 %% @private
 %%------------------------------------------------------------------------------
 init([]) ->
-    ets:new(eipmi_sessions, [
-        named_table,
-        public,
-        {write_concurrency, auto},
-        {read_concurrency, true}
-    ]),
+    EtsOptions = [named_table, public, {read_concurrency, true}],
+    try
+        ets:new(eipmi_sessions, [{write_concurrency, auto} | EtsOptions])
+    catch
+        error:badarg -> ets:new(eipmi_sessions, EtsOptions)
+    end,
     TrapPorts = application:get_env(?MODULE, trap_ports, []),
     {ok, {{one_for_one, 5, 1000}, [trap_spec(Port) || Port <- TrapPorts]}}.