zfs: extract filesystem version code to separate file & add filtering support

zfs/diff.go

@@ -1,55 +1,9 @@
 package zfs
 
 import (
-	"bytes"
-	"errors"
-	"fmt"
 	"sort"
-	"strconv"
-	"strings"
 )
 
-type VersionType string
-
-const (
-	Bookmark VersionType = "bookmark"
-	Snapshot             = "snapshot"
-)
-
-func (t VersionType) DelimiterChar() string {
-	switch t {
-	case Bookmark:
-		return "#"
-	case Snapshot:
-		return "@"
-	default:
-		panic(fmt.Sprintf("unexpected VersionType %#v", t))
-	}
-	return ""
-}
-
-type FilesystemVersion struct {
-	Type VersionType
-
-	// Display name. Should not be used for identification, only for user output
-	Name string
-
-	// GUID as exported by ZFS. Uniquely identifies a snapshot across pools
-	Guid uint64
-
-	// The TXG in which the snapshot was created. For bookmarks,
-	// this is the GUID of the snapshot it was initially tied to.
-	CreateTXG uint64
-}
-
-func (v FilesystemVersion) ToAbsPath(p DatasetPath) string {
-	var b bytes.Buffer
-	b.WriteString(p.ToString())
-	b.WriteString(v.Type.DelimiterChar())
-	b.WriteString(v.Name)
-	return b.String()
-}
-
 type fsbyCreateTXG []FilesystemVersion
 
 func (l fsbyCreateTXG) Len() int      { return len(l) }
@@ -105,56 +59,6 @@ type FilesystemDiff struct {
 	MRCAPathRight []FilesystemVersion
 }
 
-func ZFSListFilesystemVersions(fs DatasetPath) (res []FilesystemVersion, err error) {
-	var fieldLines [][]string
-	fieldLines, err = ZFSList(
-		[]string{"name", "guid", "createtxg"},
-		"-r", "-d", "1",
-		"-t", "bookmark,snapshot",
-		"-s", "createtxg", fs.ToString())
-	if err != nil {
-		return
-	}
-	res = make([]FilesystemVersion, len(fieldLines))
-	for i, line := range fieldLines {
-
-		if len(line[0]) < 3 {
-			err = errors.New(fmt.Sprintf("snapshot or bookmark name implausibly short: %s", line[0]))
-			return
-		}
-
-		snapSplit := strings.SplitN(line[0], "@", 2)
-		bookmarkSplit := strings.SplitN(line[0], "#", 2)
-		if len(snapSplit)*len(bookmarkSplit) != 2 {
-			err = errors.New(fmt.Sprintf("dataset cannot be snapshot and bookmark at the same time: %s", line[0]))
-			return
-		}
-
-		var v FilesystemVersion
-		if len(snapSplit) == 2 {
-			v.Name = snapSplit[1]
-			v.Type = Snapshot
-		} else {
-			v.Name = bookmarkSplit[1]
-			v.Type = Bookmark
-		}
-
-		if v.Guid, err = strconv.ParseUint(line[1], 10, 64); err != nil {
-			err = errors.New(fmt.Sprintf("cannot parse GUID: %s", err.Error()))
-			return
-		}
-
-		if v.CreateTXG, err = strconv.ParseUint(line[2], 10, 64); err != nil {
-			err = errors.New(fmt.Sprintf("cannot parse CreateTXG: %s", err.Error()))
-			return
-		}
-
-		res[i] = v
-
-	}
-	return
-}
-
 // we must assume left and right are ordered ascendingly by ZFS_PROP_CREATETXG and that
 // names are unique (bas ZFS_PROP_GUID replacement)
 func MakeFilesystemDiff(left, right []FilesystemVersion) (diff FilesystemDiff) {