SQLite cache

server/cache_mem.go

@@ -0,0 +1,80 @@
+package server
+
+import (
+	_ "github.com/mattn/go-sqlite3" // SQLite driver
+	"sync"
+	"time"
+)
+
+type memCache struct {
+	messages    map[string][]*message
+	mu sync.Mutex
+}
+
+var _ cache = (*memCache)(nil)
+
+func newMemCache() *memCache {
+	return &memCache{
+		messages: make(map[string][]*message),
+	}
+}
+
+func (s *memCache) AddMessage(m *message) error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if _, ok := s.messages[m.Topic]; !ok {
+		s.messages[m.Topic] = make([]*message, 0)
+	}
+	s.messages[m.Topic] = append(s.messages[m.Topic], m)
+	return nil
+}
+
+func (s *memCache) Messages(topic string, since time.Time) ([]*message, error) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if _, ok := s.messages[topic]; !ok {
+		return make([]*message, 0), nil
+	}
+	messages := make([]*message, 0) // copy!
+	for _, m := range s.messages[topic] {
+		msgTime := time.Unix(m.Time, 0)
+		if msgTime == since || msgTime.After(since) {
+			messages = append(messages, m)
+		}
+	}
+	return messages, nil
+}
+
+func (s *memCache) MessageCount(topic string) (int, error) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if _, ok := s.messages[topic]; !ok {
+		return 0, nil
+	}
+	return len(s.messages[topic]), nil
+}
+
+func (s *memCache) Topics() (map[string]*topic, error) {
+	// Hack since we know when this is called there are no messages!
+	return make(map[string]*topic), nil
+}
+
+func (s *memCache) Prune(keep time.Duration) error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	for topic, _ := range s.messages {
+		s.pruneTopic(topic, keep)
+	}
+	return nil
+}
+
+func (s *memCache) pruneTopic(topic string, keep time.Duration) {
+	for i, m := range s.messages[topic] {
+		msgTime := time.Unix(m.Time, 0)
+		if time.Since(msgTime) < keep {
+			s.messages[topic] = s.messages[topic][i:]
+			return
+		}
+	}
+	s.messages[topic] = make([]*message, 0) // all messages expired
+}