From 8b63e841ea27dc74c1216c9b03a5c21375229589 Mon Sep 17 00:00:00 2001
From: Neil Alexander <neilalexander@users.noreply.github.com>
Date: Sat, 15 Dec 2018 10:39:31 +0000
Subject: [PATCH] Make threadsafe, add cache

---
 src/yggdrasil/admin.go    | 17 +++++++----------
 src/yggdrasil/metadata.go | 34 +++++++++++++++++++++++++++++++++-
 2 files changed, 40 insertions(+), 11 deletions(-)

diff --git a/src/yggdrasil/admin.go b/src/yggdrasil/admin.go
index e773630..7c9ed1b 100644
--- a/src/yggdrasil/admin.go
+++ b/src/yggdrasil/admin.go
@@ -829,16 +829,13 @@ func (a *admin) admin_getMeta(keyString, coordString string) (metadataPayload, e
 	}
 	response := make(chan *metadataPayload, 1)
 	sendMetaRequest := func() {
-		a.core.metadata.callbacks[key] = metadataCallback{
-			created: time.Now(),
-			call: func(meta *metadataPayload) {
-				defer func() { recover() }()
-				select {
-				case response <- meta:
-				default:
-				}
-			},
-		}
+		a.core.metadata.addCallback(key, func(meta *metadataPayload) {
+			defer func() { recover() }()
+			select {
+			case response <- meta:
+			default:
+			}
+		})
 		a.core.metadata.sendMetadata(key, coords, false)
 	}
 	a.core.router.doAdmin(sendMetaRequest)
diff --git a/src/yggdrasil/metadata.go b/src/yggdrasil/metadata.go
index 7f607ed..19393b1 100644
--- a/src/yggdrasil/metadata.go
+++ b/src/yggdrasil/metadata.go
@@ -10,7 +10,9 @@ type metadata struct {
 	myMetadata      metadataPayload
 	myMetadataMutex sync.RWMutex
 	callbacks       map[boxPubKey]metadataCallback
+	callbacksMutex  sync.Mutex
 	cache           map[boxPubKey]metadataPayload
+	cacheMutex      sync.RWMutex
 }
 
 type metadataPayload []byte
@@ -38,8 +40,20 @@ func (m *metadata) init(core *Core) {
 	}()
 }
 
+// Add a callback
+func (m *metadata) addCallback(sender boxPubKey, call func(meta *metadataPayload)) {
+	m.callbacksMutex.Lock()
+	defer m.callbacksMutex.Unlock()
+	m.callbacks[sender] = metadataCallback{
+		created: time.Now(),
+		call:    call,
+	}
+}
+
 // Handles the callback, if there is one
 func (m *metadata) callback(sender boxPubKey, meta metadataPayload) {
+	m.callbacksMutex.Lock()
+	defer m.callbacksMutex.Unlock()
 	if callback, ok := m.callbacks[sender]; ok {
 		callback.call(&meta)
 		delete(m.callbacks, sender)
@@ -60,10 +74,28 @@ func (m *metadata) setMetadata(meta metadataPayload) {
 	m.myMetadata = meta
 }
 
+// Add metadata into the cache for a node
+func (m *metadata) addCachedMetadata(key boxPubKey, payload metadataPayload) {
+	m.cacheMutex.Lock()
+	defer m.cacheMutex.Unlock()
+	m.cache[key] = payload
+}
+
+// Get a metadata entry from the cache
+func (m *metadata) getCachedMetadata(key boxPubKey) metadataPayload {
+	m.cacheMutex.RLock()
+	defer m.cacheMutex.RUnlock()
+	if meta, ok := m.cache[key]; ok {
+		return meta
+	}
+	return metadataPayload{}
+}
+
 // Handles a meta request/response.
 func (m *metadata) handleMetadata(meta *sessionMeta) {
 	if meta.IsResponse {
-		m.core.metadata.callback(meta.SendPermPub, meta.Metadata)
+		m.callback(meta.SendPermPub, meta.Metadata)
+		m.addCachedMetadata(meta.SendPermPub, meta.Metadata)
 	} else {
 		m.sendMetadata(meta.SendPermPub, meta.SendCoords, true)
 	}