Implement since=ID logic in mem cache; add tests; still failing

server/cache_mem.go

@@ -60,6 +60,19 @@ func (c *memCache) Messages(topic string, since sinceMarker, scheduled bool) ([]
 	if _, ok := c.messages[topic]; !ok || since.IsNone() {
 		return make([]*message, 0), nil
 	}
+	var messages []*message
+	if since.IsID() {
+		messages = c.messagesSinceID(topic, since, scheduled)
+	} else {
+		messages = c.messagesSinceTime(topic, since, scheduled)
+	}
+	sort.Slice(messages, func(i, j int) bool {
+		return messages[i].Time < messages[j].Time
+	})
+	return messages, nil
+}
+
+func (c *memCache) messagesSinceTime(topic string, since sinceMarker, scheduled bool) []*message {
 	messages := make([]*message, 0)
 	for _, m := range c.messages[topic] {
 		_, messageScheduled := c.scheduled[m.ID]
@@ -68,10 +81,40 @@ func (c *memCache) Messages(topic string, since sinceMarker, scheduled bool) ([]
 			messages = append(messages, m)
 		}
 	}
-	sort.Slice(messages, func(i, j int) bool {
-		return messages[i].Time < messages[j].Time
-	})
-	return messages, nil
+	return messages
+}
+
+func (c *memCache) messagesSinceID(topic string, since sinceMarker, scheduled bool) []*message {
+	messages := make([]*message, 0)
+	foundID := false
+	for _, m := range c.messages[topic] {
+		_, messageScheduled := c.scheduled[m.ID]
+		if foundID {
+			if !messageScheduled || scheduled {
+				messages = append(messages, m)
+			}
+		} else if m.ID == since.ID() {
+			foundID = true
+		}
+	}
+	// Return all messages if no message was found
+	if !foundID {
+		for _, m := range c.messages[topic] {
+			_, messageScheduled := c.scheduled[m.ID]
+			if !messageScheduled || scheduled {
+				messages = append(messages, m)
+			}
+		}
+	}
+	return messages
+}
+
+func (c *memCache) maybeAppendMessage(messages []*message, m *message, since sinceMarker, scheduled bool) {
+	_, messageScheduled := c.scheduled[m.ID]
+	include := m.Time >= since.Time().Unix() && (!messageScheduled || scheduled)
+	if include {
+		messages = append(messages, m)
+	}
 }
 
 func (c *memCache) MessagesDue() ([]*message, error) {