From a99c8a42f9bd66939a547364cdb24743ca7bbfcb Mon Sep 17 00:00:00 2001
From: Shivaram Lingamneni <slingamn@cs.stanford.edu>
Date: Wed, 3 Aug 2022 00:59:00 -0400
Subject: [PATCH] remove utils.ConfigStore in favor of atomic.Pointer[T]

---
 irc/getters.go      |  2 +-
 irc/server.go       |  5 +++--
 irc/utils/config.go | 33 ---------------------------------
 3 files changed, 4 insertions(+), 36 deletions(-)
 delete mode 100644 irc/utils/config.go

diff --git a/irc/getters.go b/irc/getters.go
index 6031659f..6e5718b6 100644
--- a/irc/getters.go
+++ b/irc/getters.go
@@ -16,7 +16,7 @@ import (
 )
 
 func (server *Server) Config() (config *Config) {
-	return server.config.Get()
+	return server.config.Load()
 }
 
 func (server *Server) ChannelRegistrationEnabled() bool {
diff --git a/irc/server.go b/irc/server.go
index b4bce531..95c20eda 100644
--- a/irc/server.go
+++ b/irc/server.go
@@ -15,6 +15,7 @@ import (
 	"strconv"
 	"strings"
 	"sync"
+	"sync/atomic"
 	"syscall"
 	"time"
 
@@ -66,7 +67,7 @@ type Server struct {
 	channels          ChannelManager
 	channelRegistry   ChannelRegistry
 	clients           ClientManager
-	config            utils.ConfigStore[Config]
+	config            atomic.Pointer[Config]
 	configFilename    string
 	connectionLimiter connection_limits.Limiter
 	ctime             time.Time
@@ -707,7 +708,7 @@ func (server *Server) applyConfig(config *Config) (err error) {
 	config.Server.Cloaks.SetSecret(LoadCloakSecret(server.store))
 
 	// activate the new config
-	server.config.Set(config)
+	server.config.Store(config)
 
 	// load [dk]-lines, registered users and channels, etc.
 	if initial {
diff --git a/irc/utils/config.go b/irc/utils/config.go
deleted file mode 100644
index 73fd7165..00000000
--- a/irc/utils/config.go
+++ /dev/null
@@ -1,33 +0,0 @@
-// Copyright (c) 2022 Shivaram Lingamneni
-// released under the MIT license
-
-package utils
-
-import (
-	"sync/atomic"
-	"unsafe"
-)
-
-/*
-This can be used to implement the following pattern:
-
-1. Prepare a config object (this can be arbitrarily expensive)
-2. Take a pointer to the config object and use Set() to install it
-3. Use Get() to access the config from any goroutine
-4. To update the config, call Set() again with a new prepared config object
-5. As long as any individual config object is not modified (by any goroutine)
-   after it is installed with Set(), this is free of data races, and Get()
-   is extremely cheap (on amd64 it compiles down to plain MOV instructions).
-*/
-
-type ConfigStore[Config any] struct {
-	ptr unsafe.Pointer
-}
-
-func (c *ConfigStore[Config]) Get() *Config {
-	return (*Config)(atomic.LoadPointer(&c.ptr))
-}
-
-func (c *ConfigStore[Config]) Set(ptr *Config) {
-	atomic.StorePointer(&c.ptr, unsafe.Pointer(ptr))
-}