From 7716aa828a13dba57342837fdf81c3fbaa1cc16f Mon Sep 17 00:00:00 2001
From: "Lawrence, Rendall" <rlawrence@sot-te.ch>
Date: Sat, 16 Apr 2022 21:22:41 +0300
Subject: [PATCH] (minor) Merge commits 7a4c2ee..77b3bf9 from
 https://github.com/jzelinskie/chihaya

---
 cmd/mochi/e2e.go        |  5 ++---
 frontend/http/writer.go | 19 ++++++++++---------
 2 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/cmd/mochi/e2e.go b/cmd/mochi/e2e.go
index 20955d3..19c5c91 100644
--- a/cmd/mochi/e2e.go
+++ b/cmd/mochi/e2e.go
@@ -9,7 +9,6 @@ import (
 	"time"
 
 	"github.com/anacrolix/torrent/tracker"
-	"github.com/pkg/errors"
 	"github.com/spf13/cobra"
 
 	"github.com/sot-tech/mochi/bittorrent"
@@ -97,7 +96,7 @@ func testWithInfohash(infoHash bittorrent.InfoHash, url string, delay time.Durat
 		UserAgent:  "mochi-e2e",
 	}.Do()
 	if err != nil {
-		return errors.Wrap(err, "announce failed")
+		return fmt.Errorf("announce failed: %w", err)
 	}
 
 	if len(resp.Peers) != 1 {
@@ -125,7 +124,7 @@ func testWithInfohash(infoHash bittorrent.InfoHash, url string, delay time.Durat
 		UserAgent:  "mochi-e2e",
 	}.Do()
 	if err != nil {
-		return errors.Wrap(err, "announce failed")
+		return fmt.Errorf("announce failed: %w", err)
 	}
 
 	if len(resp.Peers) != 1 {
diff --git a/frontend/http/writer.go b/frontend/http/writer.go
index ae1bac2..bc452ae 100644
--- a/frontend/http/writer.go
+++ b/frontend/http/writer.go
@@ -2,6 +2,7 @@ package http
 
 import (
 	"errors"
+	"net"
 	"net/http"
 	"time"
 
@@ -49,26 +50,26 @@ func WriteAnnounceResponse(w http.ResponseWriter, resp *bittorrent.AnnounceRespo
 
 	// Add the peers to the dictionary in the compact format.
 	if resp.Compact {
-		var IPv4CompactDict, IPv6CompactDict []byte
-
 		// Add the IPv4 peers to the dictionary.
+		ipv4CompactDict := make([]byte, 0, (net.IPv4len+2)*len(resp.IPv4Peers))
 		for _, peer := range resp.IPv4Peers {
-			IPv4CompactDict = append(IPv4CompactDict, compact4(peer)...)
+			ipv4CompactDict = append(ipv4CompactDict, compact4(peer)...)
 		}
-		if len(IPv4CompactDict) > 0 {
-			bdict["peers"] = IPv4CompactDict
+		if len(ipv4CompactDict) > 0 {
+			bdict["peers"] = ipv4CompactDict
 		}
 
 		// Add the IPv6 peers to the dictionary.
+		ipv6CompactDict := make([]byte, 0, (net.IPv6len+2)*len(resp.IPv6Peers)) // IP + port
 		for _, peer := range resp.IPv6Peers {
-			IPv6CompactDict = append(IPv6CompactDict, compact6(peer)...)
+			ipv6CompactDict = append(ipv6CompactDict, compact6(peer)...)
 		}
-		if len(IPv6CompactDict) > 0 {
-			bdict["peers6"] = IPv6CompactDict
+		if len(ipv6CompactDict) > 0 {
+			bdict["peers6"] = ipv6CompactDict
 		}
 	} else {
 		// Add the peers to the dictionary.
-		peers := make([]map[string]any, 0, len(resp.IPv4Peers)+len(resp.IPv6Peers))
+		peers := make([]map[string]any, 0, len(resp.IPv4Peers)+len(resp.IPv6Peers)) // IP + port
 		for _, peer := range resp.IPv4Peers {
 			peers = append(peers, dict(peer))
 		}