From 678c2194dba875811ec500d5b3b818524ab93c25 Mon Sep 17 00:00:00 2001
From: Lea Anthony <lea.anthony@gmail.com>
Date: Sun, 30 Aug 2020 15:46:50 +1000
Subject: [PATCH] Add Sync Store

---
 runtime/store.go | 117 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 117 insertions(+)
 create mode 100644 runtime/store.go

diff --git a/runtime/store.go b/runtime/store.go
new file mode 100644
index 000000000..a8c4b69a6
--- /dev/null
+++ b/runtime/store.go
@@ -0,0 +1,117 @@
+package runtime
+
+// Options defines the optional data that may be used
+// when creating a Store
+type Options struct {
+
+	// The name of the store
+	Name string
+
+	// The runtime to attach the store to
+	Runtime *Runtime
+
+	// Indicates if notifying Go listeners should be notified of updates
+	// synchronously (on the current thread) or asynchronously using
+	// goroutines
+	NotifySynchronously bool
+}
+
+type StoreProvider struct {
+	runtime *Runtime
+}
+
+func NewStoreProvider(runtime *Runtime) *StoreProvider {
+	return &StoreProvider{
+		runtime: runtime,
+	}
+}
+
+// Store is where we keep named data
+type Store struct {
+	name                string
+	data                interface{}
+	eventPrefix         string
+	callbacks           []func(interface{})
+	runtime             *Runtime
+	notifySynchronously bool
+}
+
+// New creates a new store
+func (p *StoreProvider) New(name string) *Store {
+
+	result := Store{
+		name:    name,
+		runtime: p.runtime,
+	}
+
+	result.setupListner()
+
+	return &result
+}
+
+// NewWithOptions creates a new store with the given options
+func (p *StoreProvider) NewWithOptions(options Options) *Store {
+
+	result := Store{
+		name:                options.Name,
+		notifySynchronously: options.NotifySynchronously,
+	}
+
+	return &result
+}
+
+func (s *Store) setupListner() {
+	// Setup listener
+	s.runtime.Events.On("wails:sync:store:updated:"+s.name, func(data ...interface{}) {
+
+		// store the data
+		s.data = data[0]
+
+		// Notify listeners
+		s.notify()
+	})
+}
+
+// notify the listeners of the current data state
+func (s *Store) notify() {
+
+	// Notify callbacks
+	for _, callback := range s.callbacks {
+
+		if s.notifySynchronously {
+			callback(s.data)
+		} else {
+			go callback(s.data)
+		}
+
+	}
+}
+
+// Set will update the data held by the store
+// and notify listeners of the change
+func (s *Store) Set(data interface{}) {
+
+	// Save data
+	s.data = data
+
+	// Emit event
+	s.runtime.Events.Emit("wails:sync:store:updated:"+s.name, s.data)
+
+	// Notify listeners
+	s.notify()
+}
+
+// Subscribe will subscribe to updates to the store by
+// providing a callback. Any updates to the store are sent
+// to the callback
+func (s *Store) Subscribe(callback func(interface{})) {
+	s.callbacks = append(s.callbacks, callback)
+}
+
+// Update takes a function that is passed the current state.
+// The result of that function is then set as the new state
+// of the store. This will notify listeners of the change
+func (s *Store) Update(updater func(interface{}) interface{}) {
+	newData := updater(s.data)
+	s.Set(newData)
+}