chore(stdiscosrv): simplify sorting

cmd/stdiscosrv/apisrv.go

@@ -22,7 +22,7 @@ import (
 	"net"
 	"net/http"
 	"net/url"
-	"sort"
+	"slices"
 	"strconv"
 	"strings"
 	"sync"
@@ -311,7 +311,7 @@ func (s *apiSrv) handleAnnounce(deviceID protocol.DeviceID, addresses []string)
 
 	// The address slice must always be sorted for database merges to work
 	// properly.
-	sort.Sort(databaseAddressOrder(dbAddrs))
+	slices.SortFunc(dbAddrs, DatabaseAddress.Cmp)
 
 	seen := now.UnixNano()
 	if s.repl != nil {

cmd/stdiscosrv/database.go

@@ -11,6 +11,7 @@ package main
 
 import (
 	"bufio"
+	"cmp"
 	"context"
 	"encoding/binary"
 	"io"
@@ -19,7 +20,7 @@ import (
 	"net/url"
 	"os"
 	"path"
-	"sort"
+	"slices"
 	"time"
 
 	"github.com/aws/aws-sdk-go/aws"
@@ -326,6 +327,7 @@ func (s *inMemoryStore) read() error {
 			continue
 		}
 
+		slices.SortFunc(rec.Addresses, DatabaseAddress.Cmp)
 		s.m.Store(key, DatabaseRecord{
 			Addresses: rec.Addresses,
 			Seen:      rec.Seen,
@@ -339,15 +341,6 @@ func (s *inMemoryStore) read() error {
 // chosen for any duplicates.
 func merge(a, b DatabaseRecord) DatabaseRecord {
 	// Both lists must be sorted for this to work.
-	if !sort.IsSorted(databaseAddressOrder(a.Addresses)) {
-		log.Println("Warning: bug: addresses not correctly sorted in merge")
-		a.Addresses = sortedAddressCopy(a.Addresses)
-	}
-	if !sort.IsSorted(databaseAddressOrder(b.Addresses)) {
-		// no warning because this is the side we read from disk and it may
-		// legitimately predate correct sorting.
-		b.Addresses = sortedAddressCopy(b.Addresses)
-	}
 
 	res := DatabaseRecord{
 		Addresses: make([]DatabaseAddress, 0, max(len(a.Addresses), len(b.Addresses))),
@@ -425,27 +418,6 @@ func expire(addrs []DatabaseAddress, now int64) []DatabaseAddress {
 	return addrs
 }
 
-func sortedAddressCopy(addrs []DatabaseAddress) []DatabaseAddress {
-	sorted := make([]DatabaseAddress, len(addrs))
-	copy(sorted, addrs)
-	sort.Sort(databaseAddressOrder(sorted))
-	return sorted
-}
-
-type databaseAddressOrder []DatabaseAddress
-
-func (s databaseAddressOrder) Less(a, b int) bool {
-	return s[a].Address < s[b].Address
-}
-
-func (s databaseAddressOrder) Swap(a, b int) {
-	s[a], s[b] = s[b], s[a]
-}
-
-func (s databaseAddressOrder) Len() int {
-	return len(s)
-}
-
 func s3Upload(r io.Reader) error {
 	sess, err := session.NewSession(&aws.Config{
 		Region:   aws.String("fr-par"),
@@ -478,3 +450,10 @@ func s3Download(w io.WriterAt) error {
 	})
 	return err
 }
+
+func (d DatabaseAddress) Cmp(other DatabaseAddress) (n int) {
+	if c := cmp.Compare(d.Address, other.Address); c != 0 {
+		return c
+	}
+	return cmp.Compare(d.Expires, other.Expires)
+}