From b8e81240fd38c5409bfed73e3541a24d913f0a33 Mon Sep 17 00:00:00 2001
From: fclairamb <florent.clairambault@gmail.com>
Date: Sun, 3 Mar 2024 13:49:21 +0100
Subject: [PATCH] Moving some code to reduce cyclomatic complexity

---
 .golangci.yml     |  6 +++++
 client_handler.go | 62 ++++++++++++++++++++++++++---------------------
 server.go         | 27 +++++++++++++--------
 3 files changed, 58 insertions(+), 37 deletions(-)

diff --git a/.golangci.yml b/.golangci.yml
index f5647385..9d2d0256 100644
--- a/.golangci.yml
+++ b/.golangci.yml
@@ -161,8 +161,14 @@ linters:
     disable-all: true
     enable:
         - asciicheck
+        - asasalint
+        - bidichk
         - bodyclose
         # - deadcode -> unused
+        - containedctx
+        # - contextcheck -> creates an odd error here: https://github.com/fclairamb/ftpserverlib/blob/4d7c663e9e0b2650673fc2e0fcdb443895f2a1b9/server.go#L234
+        # - copyloopvar -> unknown in v1.56.2 ???
+        - cyclop
         - depguard
         - dogsled
         - dupl
diff --git a/client_handler.go b/client_handler.go
index d3313295..48193b1c 100644
--- a/client_handler.go
+++ b/client_handler.go
@@ -410,47 +410,55 @@ func (c *clientHandler) HandleCommands() {
 	}
 
 	for {
-		if c.reader == nil {
-			if c.debug {
-				c.logger.Debug("Client disconnected", "clean", true)
-			}
-
+		if c.readCommand() {
 			return
 		}
+	}
+}
 
-		// florent(2018-01-14): #58: IDLE timeout: Preparing the deadline before we read
-		if c.server.settings.IdleTimeout > 0 {
-			if err := c.conn.SetDeadline(
-				time.Now().Add(time.Duration(time.Second.Nanoseconds() * int64(c.server.settings.IdleTimeout)))); err != nil {
-				c.logger.Error("Network error", "err", err)
-			}
+func (c *clientHandler) readCommand() bool {
+	if c.reader == nil {
+		if c.debug {
+			c.logger.Debug("Client disconnected", "clean", true)
 		}
 
-		lineSlice, isPrefix, err := c.reader.ReadLine()
-
-		if isPrefix {
-			if c.debug {
-				c.logger.Warn("Received line too long, disconnecting client",
-					"size", len(lineSlice))
-			}
+		return true
+	}
 
-			return
+	// florent(2018-01-14): #58: IDLE timeout: Preparing the deadline before we read
+	if c.server.settings.IdleTimeout > 0 {
+		if err := c.conn.SetDeadline(
+			time.Now().Add(time.Duration(time.Second.Nanoseconds() * int64(c.server.settings.IdleTimeout)))); err != nil {
+			c.logger.Error("Network error", "err", err)
 		}
+	}
 
-		if err != nil {
-			c.handleCommandsStreamError(err)
+	lineSlice, isPrefix, err := c.reader.ReadLine()
 
-			return
+	if isPrefix {
+		if c.debug {
+			c.logger.Warn("Received line too long, disconnecting client",
+				"size", len(lineSlice))
 		}
 
-		line := string(lineSlice)
+		return true
+	}
 
-		if c.debug {
-			c.logger.Debug("Received line", "line", line)
-		}
+	if err != nil {
+		c.handleCommandsStreamError(err)
 
-		c.handleCommand(line)
+		return true
 	}
+
+	line := string(lineSlice)
+
+	if c.debug {
+		c.logger.Debug("Received line", "line", line)
+	}
+
+	c.handleCommand(line)
+
+	return false
 }
 
 func (c *clientHandler) handleCommandsStreamError(err error) {
diff --git a/server.go b/server.go
index 0462b219..5e876adc 100644
--- a/server.go
+++ b/server.go
@@ -118,17 +118,10 @@ func (server *FtpServer) loadSettings() error {
 	}
 
 	if s.PublicHost != "" {
-		parsedIP := net.ParseIP(s.PublicHost)
-		if parsedIP == nil {
-			return &ipValidationError{error: fmt.Sprintf("invalid passive IP %#v", s.PublicHost)}
-		}
-
-		parsedIP = parsedIP.To4()
-		if parsedIP == nil {
-			return &ipValidationError{error: fmt.Sprintf("invalid IPv4 passive IP %#v", s.PublicHost)}
+		s.PublicHost, err = parseIPv4(s.PublicHost)
+		if err != nil {
+			return err
 		}
-
-		s.PublicHost = parsedIP.String()
 	}
 
 	if s.Listener == nil && s.ListenAddr == "" {
@@ -153,6 +146,20 @@ func (server *FtpServer) loadSettings() error {
 	return nil
 }
 
+func parseIPv4(publicHost string) (string, error) {
+	parsedIP := net.ParseIP(publicHost)
+	if parsedIP == nil {
+		return "", &ipValidationError{error: fmt.Sprintf("invalid passive IP %#v", publicHost)}
+	}
+
+	parsedIP = parsedIP.To4()
+	if parsedIP == nil {
+		return "", &ipValidationError{error: fmt.Sprintf("invalid IPv4 passive IP %#v", publicHost)}
+	}
+
+	return parsedIP.String(), nil
+}
+
 // Listen starts the listening
 // It's not a blocking call
 func (server *FtpServer) Listen() error {