whisper: general cleanups, documentation

whisper/filter.go

@@ -1,10 +1,13 @@
+// Contains the message filter for fine grained subscriptions.
+
 package whisper
 
 import "crypto/ecdsa"
 
+// Filter is used to subscribe to specific types of whisper messages.
 type Filter struct {
-	To     *ecdsa.PublicKey
-	From   *ecdsa.PublicKey
-	Topics []Topic
-	Fn     func(*Message)
+	To     *ecdsa.PublicKey // Recipient of the message
+	From   *ecdsa.PublicKey // Sender of the message
+	Topics []Topic          // Topics to watch messages on
+	Fn     func(*Message)   // Handler in case of a match
 }