From 99a06e3f504af587b050c8a79adbc96ab80245f4 Mon Sep 17 00:00:00 2001
From: Matt Joiner <anacrolix@gmail.com>
Date: Mon, 22 Jun 2015 19:44:59 +1000
Subject: [PATCH] Move IP blocklist loading into iplist package

---
 client.go        | 28 +---------------------------
 iplist/iplist.go | 37 +++++++++++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+), 27 deletions(-)

diff --git a/client.go b/client.go
index 171abd71..2c9d522e 100644
--- a/client.go
+++ b/client.go
@@ -377,33 +377,7 @@ func (cl *Client) setEnvBlocklist() (err error) {
 		return
 	}
 	defer f.Close()
-	var ranges []iplist.Range
-	uniqStrs := make(map[string]string)
-	scanner := bufio.NewScanner(f)
-	lineNum := 1
-	for scanner.Scan() {
-		r, ok, lineErr := iplist.ParseBlocklistP2PLine(scanner.Bytes())
-		if lineErr != nil {
-			err = fmt.Errorf("error reading torrent blocklist line %d: %s", lineNum, lineErr)
-			return
-		}
-		lineNum++
-		if !ok {
-			continue
-		}
-		if s, ok := uniqStrs[r.Description]; ok {
-			r.Description = s
-		} else {
-			uniqStrs[r.Description] = r.Description
-		}
-		ranges = append(ranges, r)
-	}
-	err = scanner.Err()
-	if err != nil {
-		err = fmt.Errorf("error reading torrent blocklist: %s", err)
-		return
-	}
-	cl.ipBlockList = iplist.New(ranges)
+	cl.ipBlockList, err = iplist.NewFromReader(f)
 	return
 }
 
diff --git a/iplist/iplist.go b/iplist/iplist.go
index 93fb9b31..18d6b0a3 100644
--- a/iplist/iplist.go
+++ b/iplist/iplist.go
@@ -1,9 +1,13 @@
+// Package iplist handles the P2P Plaintext Format described by
+// https://en.wikipedia.org/wiki/PeerGuardian#P2P_plaintext_format.
 package iplist
 
 import (
+	"bufio"
 	"bytes"
 	"errors"
 	"fmt"
+	"io"
 	"net"
 	"sort"
 )
@@ -123,3 +127,36 @@ func ParseBlocklistP2PLine(l []byte) (r Range, ok bool, err error) {
 	ok = true
 	return
 }
+
+// Creates an IPList from a line-delimited P2P Plaintext file.
+func NewFromReader(f io.Reader) (ret *IPList, err error) {
+	var ranges []Range
+	// There's a lot of similar descriptions, so we maintain a pool and reuse
+	// them to reduce memory overhead.
+	uniqStrs := make(map[string]string)
+	scanner := bufio.NewScanner(f)
+	lineNum := 1
+	for scanner.Scan() {
+		r, ok, lineErr := ParseBlocklistP2PLine(scanner.Bytes())
+		if lineErr != nil {
+			err = fmt.Errorf("error parsing line %d: %s", lineNum, lineErr)
+			return
+		}
+		lineNum++
+		if !ok {
+			continue
+		}
+		if s, ok := uniqStrs[r.Description]; ok {
+			r.Description = s
+		} else {
+			uniqStrs[r.Description] = r.Description
+		}
+		ranges = append(ranges, r)
+	}
+	err = scanner.Err()
+	if err != nil {
+		return
+	}
+	ret = New(ranges)
+	return
+}
-- 
2.48.1