First implementation

vendor/github.com/eclipse/paho.mqtt.golang/memstore.go

@@ -0,0 +1,138 @@
+/*
+ * Copyright (c) 2013 IBM Corp.
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *    Seth Hoenig
+ *    Allan Stockdill-Mander
+ *    Mike Robertson
+ */
+
+package mqtt
+
+import (
+	"sync"
+
+	"github.com/eclipse/paho.mqtt.golang/packets"
+)
+
+// MemoryStore implements the store interface to provide a "persistence"
+// mechanism wholly stored in memory. This is only useful for
+// as long as the client instance exists.
+type MemoryStore struct {
+	sync.RWMutex
+	messages map[string]packets.ControlPacket
+	opened   bool
+}
+
+// NewMemoryStore returns a pointer to a new instance of
+// MemoryStore, the instance is not initialized and ready to
+// use until Open() has been called on it.
+func NewMemoryStore() *MemoryStore {
+	store := &MemoryStore{
+		messages: make(map[string]packets.ControlPacket),
+		opened:   false,
+	}
+	return store
+}
+
+// Open initializes a MemoryStore instance.
+func (store *MemoryStore) Open() {
+	store.Lock()
+	defer store.Unlock()
+	store.opened = true
+	DEBUG.Println(STR, "memorystore initialized")
+}
+
+// Put takes a key and a pointer to a Message and stores the
+// message.
+func (store *MemoryStore) Put(key string, message packets.ControlPacket) {
+	store.Lock()
+	defer store.Unlock()
+	if !store.opened {
+		ERROR.Println(STR, "Trying to use memory store, but not open")
+		return
+	}
+	store.messages[key] = message
+}
+
+// Get takes a key and looks in the store for a matching Message
+// returning either the Message pointer or nil.
+func (store *MemoryStore) Get(key string) packets.ControlPacket {
+	store.RLock()
+	defer store.RUnlock()
+	if !store.opened {
+		ERROR.Println(STR, "Trying to use memory store, but not open")
+		return nil
+	}
+	mid := mIDFromKey(key)
+	m := store.messages[key]
+	if m == nil {
+		CRITICAL.Println(STR, "memorystore get: message", mid, "not found")
+	} else {
+		DEBUG.Println(STR, "memorystore get: message", mid, "found")
+	}
+	return m
+}
+
+// All returns a slice of strings containing all the keys currently
+// in the MemoryStore.
+func (store *MemoryStore) All() []string {
+	store.RLock()
+	defer store.RUnlock()
+	if !store.opened {
+		ERROR.Println(STR, "Trying to use memory store, but not open")
+		return nil
+	}
+	keys := []string{}
+	for k := range store.messages {
+		keys = append(keys, k)
+	}
+	return keys
+}
+
+// Del takes a key, searches the MemoryStore and if the key is found
+// deletes the Message pointer associated with it.
+func (store *MemoryStore) Del(key string) {
+	store.Lock()
+	defer store.Unlock()
+	if !store.opened {
+		ERROR.Println(STR, "Trying to use memory store, but not open")
+		return
+	}
+	mid := mIDFromKey(key)
+	m := store.messages[key]
+	if m == nil {
+		WARN.Println(STR, "memorystore del: message", mid, "not found")
+	} else {
+		delete(store.messages, key)
+		DEBUG.Println(STR, "memorystore del: message", mid, "was deleted")
+	}
+}
+
+// Close will disallow modifications to the state of the store.
+func (store *MemoryStore) Close() {
+	store.Lock()
+	defer store.Unlock()
+	if !store.opened {
+		ERROR.Println(STR, "Trying to close memory store, but not open")
+		return
+	}
+	store.opened = false
+	DEBUG.Println(STR, "memorystore closed")
+}
+
+// Reset eliminates all persisted message data in the store.
+func (store *MemoryStore) Reset() {
+	store.Lock()
+	defer store.Unlock()
+	if !store.opened {
+		ERROR.Println(STR, "Trying to reset memory store, but not open")
+	}
+	store.messages = make(map[string]packets.ControlPacket)
+	WARN.Println(STR, "memorystore wiped")
+}