mirror update: add -max-versions to keep the N most recent versions

deb/list.go

@@ -173,33 +173,21 @@ func (l *PackageList) ForEach(handler func(*Package) error) error {
 }
 
 // FilterLatest creates a copy of the package list containing only the
-// latest version for each package name/architecture pair.
-func (l *PackageList) FilterLatest() (*PackageList, error) {
+// count latest versions for each package name/architecture pair.
+func (l *PackageList) FilterLatest(count int) (*PackageList, error) {
 	if l == nil {
 		return nil, fmt.Errorf("package list is nil")
 	}
 
-	filtered := make(map[string]*Package, l.Len())
+	if count < 1 {
+		return nil, fmt.Errorf("number of latest versions should be at least 1, got %d", count)
+	}
+
+	groups := make(map[string][]*Package, l.Len())
 
 	err := l.ForEach(func(p *Package) error {
 		key := p.Architecture + "|" + p.Name
-
-		existing, found := filtered[key]
-		if !found {
-			filtered[key] = p
-			return nil
-		}
-
-		cmp, compareErr := CompareVersions(p.Version, existing.Version)
-		switch compareErr {
-		case nil:
-			if cmp > 0 {
-				filtered[key] = p
-			}
-		case RightInvalid:
-			filtered[key] = p
-		case LeftInvalid, BothInvalid:
-		}
+		groups[key] = append(groups[key], p)
 
 		return nil
 	})
@@ -207,11 +195,26 @@ func (l *PackageList) FilterLatest() (*PackageList, error) {
 		return nil, err
 	}
 
-	result := NewPackageListWithDuplicates(l.duplicatesAllowed, len(filtered))
+	result := NewPackageListWithDuplicates(l.duplicatesAllowed, len(groups)*count)
 
-	for _, pkg := range filtered {
-		if err = result.Add(pkg); err != nil {
-			return nil, err
+	for _, pkgs := range groups {
+		// sort from latest to oldest
+		sort.Slice(pkgs, func(i, j int) bool {
+			return CompareVersions(pkgs[i].Version, pkgs[j].Version) > 0
+		})
+
+		versions := 0
+		for i, p := range pkgs {
+			if i == 0 || CompareVersions(p.Version, pkgs[i-1].Version) != 0 {
+				versions++
+				if versions > count {
+					break
+				}
+			}
+
+			if err = result.Add(p); err != nil {
+				return nil, err
+			}
 		}
 	}
 

deb/remote.go

@@ -698,18 +698,26 @@ func (repo *RemoteRepo) ApplyFilter(dependencyOptions int, filterQuery PackageQu
 	return
 }
 
-// BuildDownloadQueue builds queue, discards current PackageList
-func (repo *RemoteRepo) BuildDownloadQueue(packagePool aptly.PackagePool, packageCollection *PackageCollection, checksumStorage aptly.ChecksumStorage, skipExistingPackages, latestOnly bool) (queue []PackageDownloadTask, downloadSize int64, err error) {
+// FilterLatest keeps only count latest versions of each package (per architecture)
+func (repo *RemoteRepo) FilterLatest(count int) (oldLen, newLen int, err error) {
 	if repo.packageList == nil {
 		err = fmt.Errorf("package list is empty, please (re)download package indexes")
 		return
 	}
 
-	if latestOnly {
-		repo.packageList, err = repo.packageList.FilterLatest()
-		if err != nil {
-			return
-		}
+	oldLen = repo.packageList.Len()
+	repo.packageList, err = repo.packageList.FilterLatest(count)
+	if repo.packageList != nil {
+		newLen = repo.packageList.Len()
+	}
+	return
+}
+
+// BuildDownloadQueue builds queue, discards current PackageList
+func (repo *RemoteRepo) BuildDownloadQueue(packagePool aptly.PackagePool, packageCollection *PackageCollection, checksumStorage aptly.ChecksumStorage, skipExistingPackages bool) (queue []PackageDownloadTask, downloadSize int64, err error) {
+	if repo.packageList == nil {
+		err = fmt.Errorf("package list is empty, please (re)download package indexes")
+		return
 	}
 
 	queue = make([]PackageDownloadTask, 0, repo.packageList.Len())