Prepare log functions for filters. Init all filter functions by assigning empty stubs. #26

Config.go

@@ -16,7 +16,7 @@ import (
 )
 
 // Version is the current core library version
-const Version = "Alpha 2/09.06.2021"
+const Version = "Alpha 2/28.06.2021"
 
 var config struct {
 	LogFile string `yaml:"LogFile"` // Log file

Connection.go

@@ -175,9 +175,7 @@ func (peer *PeerInfo) registerConnection(incoming *Connection) (result *Connecti
 	peer.connectionActive = append(peer.connectionActive, incoming)
 	peer.setConnectionLatest(incoming)
 
-	if Filters.NewPeerConnection != nil {
-		Filters.NewPeerConnection(peer, incoming)
-	}
+	Filters.NewPeerConnection(peer, incoming)
 
 	return incoming
 }

Filter.go

@@ -8,6 +8,8 @@ Filters allow the caller to intercept events to log, modify, or prevent.
 
 package core
 
+import "log"
+
 // Filters contains all functions to install the hook. Use nil for unused.
 // The functions are called sequentially and block execution; if the filter takes a long time it should start a Go routine.
 var Filters struct {
@@ -18,4 +20,20 @@ var Filters struct {
 
 	// NewPeerConnection is called for each new established connection to a peer. Note that connections might be dropped and reconnected at anytime.
 	NewPeerConnection func(peer *PeerInfo, connection *Connection)
+
+	// LogError is called for any error. If this function is overwritten by the caller, the caller must write errors into the log file if desired, or call DefaultLogError.
+	LogError func(function, format string, v ...interface{})
+}
+
+func initFilters() {
+	// Set default filters to blank functions so they can be safely called without constant nil checks.
+	Filters.NewPeer = func(peer *PeerInfo, connection *Connection) {}
+	Filters.NewPeerConnection = func(peer *PeerInfo, connection *Connection) {}
+
+	Filters.LogError = DefaultLogError
+}
+
+// DefaultLogError is the default error logging function
+func DefaultLogError(function, format string, v ...interface{}) {
+	log.Printf("["+function+"] "+format, v...)
 }

Peer ID.go

@@ -145,12 +145,8 @@ func PeerlistAdd(PublicKey *btcec.PublicKey, connections ...*Connection) (peer *
 		}
 	}
 
-	if Filters.NewPeer != nil {
-		Filters.NewPeer(peer, connections[0])
-	}
-	if Filters.NewPeerConnection != nil {
-		Filters.NewPeerConnection(peer, connections[0])
-	}
+	Filters.NewPeer(peer, connections[0])
+	Filters.NewPeerConnection(peer, connections[0])
 
 	return peer, true
 }

Peernet.go

@@ -8,6 +8,7 @@ package core
 
 // Init initializes the client. The config must be loaded first!
 func Init() {
+	initFilters()
 	initPeerID()
 	initKademlia()
 	initMessageSequence()