Mono repo -> Master (#22553)

Combines the following repositories into one:

https://github.com/mattermost/mattermost-server
https://github.com/mattermost/mattermost-webapp
https://github.com/mattermost/focalboard
https://github.com/mattermost/mattermost-plugin-playbooks

server/config/emitter.go

@@ -0,0 +1,66 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package config
+
+import (
+	"sync"
+
+	"github.com/mattermost/mattermost-server/v6/model"
+	"github.com/mattermost/mattermost-server/v6/server/platform/shared/mlog"
+)
+
+// Listener is a callback function invoked when the configuration changes.
+type Listener func(oldCfg, newCfg *model.Config)
+
+// emitter enables threadsafe registration and broadcasting to configuration listeners
+type emitter struct {
+	listeners sync.Map
+}
+
+// AddListener adds a callback function to invoke when the configuration is modified.
+func (e *emitter) AddListener(listener Listener) string {
+	id := model.NewId()
+	e.listeners.Store(id, listener)
+	return id
+}
+
+// RemoveListener removes a callback function using an id returned from AddListener.
+func (e *emitter) RemoveListener(id string) {
+	e.listeners.Delete(id)
+}
+
+// invokeConfigListeners synchronously notifies all listeners about the configuration change.
+func (e *emitter) invokeConfigListeners(oldCfg, newCfg *model.Config) {
+	e.listeners.Range(func(key, value any) bool {
+		listener := value.(Listener)
+		listener(oldCfg, newCfg)
+		return true
+	})
+}
+
+// srcEmitter enables threadsafe registration and broadcasting to configuration listeners
+type logSrcEmitter struct {
+	listeners sync.Map
+}
+
+// AddListener adds a callback function to invoke when the configuration is modified.
+func (e *logSrcEmitter) AddListener(listener LogSrcListener) string {
+	id := model.NewId()
+	e.listeners.Store(id, listener)
+	return id
+}
+
+// RemoveListener removes a callback function using an id returned from AddListener.
+func (e *logSrcEmitter) RemoveListener(id string) {
+	e.listeners.Delete(id)
+}
+
+// invokeConfigListeners synchronously notifies all listeners about the configuration change.
+func (e *logSrcEmitter) invokeConfigListeners(oldCfg, newCfg mlog.LoggerConfiguration) {
+	e.listeners.Range(func(key, value any) bool {
+		listener := value.(LogSrcListener)
+		listener(oldCfg, newCfg)
+		return true
+	})
+}