pre-allocate peers in memory.AnnouncePeers

* change go version to 1.19 in linter

.github/workflows/lint.yaml

@@ -15,7 +15,7 @@ jobs:
             -   uses: "actions/checkout@v3"
             -   uses: "actions/setup-go@v3"
                 with:
-                    go-version: "^1.18"
+                    go-version: "^1.19"
             -   uses: "authzed/actions/gofumpt@main"
             -   uses: "authzed/actions/go-mod-tidy@main"
             -   uses: "authzed/actions/go-generate@main"

.golangci.yaml

@@ -1,8 +1,6 @@
 ---
 run:
-    # mochi in not written with generics (a.t.m),
-    # so we can check with 1.17
-    go: "1.17"
+    go: "1.19"
     timeout: "5m"
 output:
     sort-results: true

storage/memory/storage.go

@@ -5,13 +5,13 @@ package memory
 import (
 	"context"
 	"encoding/binary"
-	"github.com/cornelk/hashmap"
 	"math"
 	"runtime"
 	"sync"
 	"sync/atomic"
 	"time"
 
+	"github.com/cornelk/hashmap"
 	"github.com/sot-tech/mochi/bittorrent"
 	"github.com/sot-tech/mochi/pkg/conf"
 	"github.com/sot-tech/mochi/pkg/log"
@@ -160,15 +160,15 @@ func (ps *peerStore) ScheduleStatisticsCollection(reportInterval time.Duration)
 					before := time.Now()
 					// aggregates metrics over all shards and then posts them to
 					// prometheus.
-					var numInfohashes, numSeeders, numLeechers uint64
+					var numInfoHashes, numSeeders, numLeechers uint64
 
 					for _, s := range ps.shards {
-						numInfohashes += uint64(s.swarms.Len())
-						numSeeders += uint64(s.numSeeders.Load())
-						numLeechers += uint64(s.numLeechers.Load())
+						numInfoHashes += uint64(s.swarms.Len())
+						numSeeders += s.numSeeders.Load()
+						numLeechers += s.numLeechers.Load()
 					}
 
-					storage.PromInfoHashesCount.Set(float64(numInfohashes))
+					storage.PromInfoHashesCount.Set(float64(numInfoHashes))
 					storage.PromSeedersCount.Set(float64(numSeeders))
 					storage.PromLeechersCount.Set(float64(numLeechers))
 					logger.Debug().TimeDiff("timeTaken", time.Now(), before).Msg("populate prom complete")
@@ -201,13 +201,13 @@ func (ps *peerStore) PutSeeder(_ context.Context, ih bittorrent.InfoHash, p bitt
 		Msg("put seeder")
 
 	sh := ps.shards[ps.shardIndex(ih, p.Addr().Is6())]
-	sw, pId := sh.ginSwarm(ih), p.RawString()
+	sw, pID := sh.ginSwarm(ih), p.RawString()
 
-	if _, exists := sw.seeders.Get(pId); !exists {
+	if _, exists := sw.seeders.Get(pID); !exists {
 		sh.numSeeders.Add(1)
 	}
 
-	sw.seeders.Set(pId, timecache.NowUnixNano())
+	sw.seeders.Set(pID, timecache.NowUnixNano())
 
 	return nil
 }
@@ -247,13 +247,13 @@ func (ps *peerStore) PutLeecher(_ context.Context, ih bittorrent.InfoHash, p bit
 		Msg("put leecher")
 
 	sh := ps.shards[ps.shardIndex(ih, p.Addr().Is6())]
-	sw, pId := sh.ginSwarm(ih), p.RawString()
+	sw, pID := sh.ginSwarm(ih), p.RawString()
 
-	if _, exists := sw.leechers.Get(pId); !exists {
+	if _, exists := sw.leechers.Get(pID); !exists {
 		sh.numLeechers.Add(1)
 	}
 
-	sw.leechers.Set(pId, timecache.NowUnixNano())
+	sw.leechers.Set(pID, timecache.NowUnixNano())
 
 	return nil
 }
@@ -293,45 +293,21 @@ func (ps *peerStore) GraduateLeecher(_ context.Context, ih bittorrent.InfoHash,
 		Msg("graduate leecher")
 
 	sh := ps.shards[ps.shardIndex(ih, p.Addr().Is6())]
-	sw, pId := sh.ginSwarm(ih), p.RawString()
+	sw, pID := sh.ginSwarm(ih), p.RawString()
 
-	if sw.leechers.Del(pId) {
+	if sw.leechers.Del(pID) {
 		sh.numLeechers.Add(decrUint64)
 	}
 
-	if _, exists := sw.seeders.Get(pId); !exists {
+	if _, exists := sw.seeders.Get(pID); !exists {
 		sh.numSeeders.Add(1)
 	}
 
-	sw.seeders.Set(pId, timecache.NowUnixNano())
+	sw.seeders.Set(pID, timecache.NowUnixNano())
 
 	return nil
 }
 
-func parsePeers(peersMap *hashmap.Map[string, int64], maxCount int) (peers []bittorrent.Peer) {
-	peersMap.Range(func(pId string, _ int64) bool {
-		p, _ := bittorrent.NewPeer(pId)
-		peers = append(peers, p)
-		maxCount--
-		return maxCount > 0
-	})
-	return
-}
-
-func (ps *peerStore) getPeers(shard *peerShard, ih bittorrent.InfoHash, numWant int, forSeeder bool) (peers []bittorrent.Peer) {
-	if sw, ok := shard.swarms.Get(ih); ok {
-		if forSeeder {
-			peers = parsePeers(sw.leechers, numWant)
-		} else {
-			peers = append(peers, parsePeers(sw.seeders, numWant)...)
-			if numWant -= len(peers); numWant > 0 {
-				peers = append(peers, parsePeers(sw.leechers, numWant)...)
-			}
-		}
-	}
-	return
-}
-
 func (ps *peerStore) AnnouncePeers(_ context.Context, ih bittorrent.InfoHash, forSeeder bool, numWant int, v6 bool) (peers []bittorrent.Peer, err error) {
 	select {
 	case <-ps.closed:
@@ -345,7 +321,23 @@ func (ps *peerStore) AnnouncePeers(_ context.Context, ih bittorrent.InfoHash, fo
 		Bool("v6", v6).
 		Msg("announce peers")
 
-	peers = ps.getPeers(ps.shards[ps.shardIndex(ih, v6)], ih, numWant, forSeeder)
+	if sw, ok := ps.shards[ps.shardIndex(ih, v6)].swarms.Get(ih); ok {
+		peers = make([]bittorrent.Peer, 0, numWant/2)
+		rangeFn := func(pID string, _ int64) bool {
+			p, _ := bittorrent.NewPeer(pID)
+			peers = append(peers, p)
+			numWant--
+			return numWant > 0
+		}
+		if forSeeder {
+			sw.leechers.Range(rangeFn)
+		} else {
+			sw.seeders.Range(rangeFn)
+			if numWant > 0 {
+				sw.leechers.Range(rangeFn)
+			}
+		}
+	}
 
 	return
 }
@@ -453,40 +445,37 @@ func (ps *peerStore) gc(cutoff time.Time) {
 
 	for _, shard := range ps.shards {
 		infoHashes := make([]bittorrent.InfoHash, 0, shard.swarms.Len())
-		shard.swarms.Range(func(ih bittorrent.InfoHash, sw swarm) bool {
+		shard.swarms.Range(func(ih bittorrent.InfoHash, _ swarm) bool {
 			infoHashes = append(infoHashes, ih)
 			return true
 		})
 		runtime.Gosched()
 
 		for _, ih := range infoHashes {
-
 			sw, stillExists := shard.swarms.Get(ih)
 			if !stillExists {
 				runtime.Gosched()
 				continue
 			}
 
-			sw.leechers.Range(func(pId string, mtime int64) bool {
+			sw.leechers.Range(func(pID string, mtime int64) bool {
 				if mtime <= cutoffUnix {
-					sw.leechers.Del(pId)
+					sw.leechers.Del(pID)
 					shard.numLeechers.Add(decrUint64)
 				}
 				return true
 			})
 
-			sw.seeders.Range(func(pId string, mtime int64) bool {
+			sw.seeders.Range(func(pID string, mtime int64) bool {
 				if mtime <= cutoffUnix {
-					sw.seeders.Del(pId)
+					sw.seeders.Del(pID)
 					shard.numSeeders.Add(decrUint64)
 				}
 				return true
 			})
 
 			if sw.leechers.Len()|sw.seeders.Len() == 0 {
-				shard.Lock()
 				shard.swarms.Del(ih)
-				shard.Unlock()
 			}
 
 			runtime.Gosched()