From 084f3bc1ee6c53687e2714499efbf9544cdfda5b Mon Sep 17 00:00:00 2001
From: Kleissner <peter@kleissner.investments>
Date: Mon, 28 Jun 2021 02:37:31 +0200
Subject: [PATCH] Prepare log functions for filters. Init all filter functions
 by assigning empty stubs. #26

---
 Config.go     |  2 +-
 Connection.go |  4 +---
 Filter.go     | 18 ++++++++++++++++++
 Peer ID.go    |  8 ++------
 Peernet.go    |  1 +
 5 files changed, 23 insertions(+), 10 deletions(-)

diff --git a/Config.go b/Config.go
index 74bc000..774d4fc 100644
--- a/Config.go
+++ b/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
diff --git a/Connection.go b/Connection.go
index a4db005..d655bd2 100644
--- a/Connection.go
+++ b/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
 }
diff --git a/Filter.go b/Filter.go
index e5ed4d0..bfee8e7 100644
--- a/Filter.go
+++ b/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...)
 }
diff --git a/Peer ID.go b/Peer ID.go
index ac831af..47e3bf6 100644
--- a/Peer ID.go	
+++ b/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
 }
diff --git a/Peernet.go b/Peernet.go
index aef0a2f..2f9a403 100644
--- a/Peernet.go
+++ b/Peernet.go
@@ -8,6 +8,7 @@ package core
 
 // Init initializes the client. The config must be loaded first!
 func Init() {
+	initFilters()
 	initPeerID()
 	initKademlia()
 	initMessageSequence()