From 51af8807016cbdfd33fc62d83c6ee1f1a6100a00 Mon Sep 17 00:00:00 2001
From: Christian Schwarz <me@cschwarz.com>
Date: Sun, 12 Nov 2017 23:02:23 +0100
Subject: [PATCH] refactor: parametrize PrefixFilter VersionType check

refs #34
---
 cmd/autosnap.go          |  2 +-
 cmd/config_fsvfilter.go  | 29 ++++++++++++++++-------------
 cmd/config_job_local.go  |  2 +-
 cmd/config_job_source.go |  2 +-
 cmd/prune.go             |  3 ++-
 5 files changed, 21 insertions(+), 17 deletions(-)

diff --git a/cmd/autosnap.go b/cmd/autosnap.go
index 449a007..8018089 100644
--- a/cmd/autosnap.go
+++ b/cmd/autosnap.go
@@ -47,7 +47,7 @@ func (a *IntervalAutosnap) Run(ctx context.Context, didSnaps chan struct{}) {
 
 		l := a.log.WithField(logFSField, d.ToString())
 
-		fsvs, err := zfs.ZFSListFilesystemVersions(d, &PrefixSnapshotFilter{a.Prefix})
+		fsvs, err := zfs.ZFSListFilesystemVersions(d, NewTypedPrefixFilter(a.Prefix, zfs.Snapshot))
 		if err != nil {
 			l.WithError(err).Error("cannot list filesystem versions")
 			continue
diff --git a/cmd/config_fsvfilter.go b/cmd/config_fsvfilter.go
index c1c3754..8e13dd5 100644
--- a/cmd/config_fsvfilter.go
+++ b/cmd/config_fsvfilter.go
@@ -6,8 +6,18 @@ import (
 	"strings"
 )
 
-type PrefixSnapshotFilter struct {
-	Prefix string
+type PrefixFilter struct {
+	prefix    string
+	fstype    zfs.VersionType
+	fstypeSet bool // optionals anyone?
+}
+
+func NewPrefixFilter(prefix string) *PrefixFilter {
+	return &PrefixFilter{prefix: prefix}
+}
+
+func NewTypedPrefixFilter(prefix string, versionType zfs.VersionType) *PrefixFilter {
+	return &PrefixFilter{prefix, versionType, true}
 }
 
 func parseSnapshotPrefix(i string) (p string, err error) {
@@ -19,15 +29,8 @@ func parseSnapshotPrefix(i string) (p string, err error) {
 	return
 }
 
-func parsePrefixSnapshotFilter(i string) (f *PrefixSnapshotFilter, err error) {
-	if !(len(i) > 0) {
-		err = errors.Errorf("snapshot prefix must be longer than 0 characters")
-		return
-	}
-	f = &PrefixSnapshotFilter{i}
-	return
-}
-
-func (f *PrefixSnapshotFilter) Filter(fsv zfs.FilesystemVersion) (accept bool, err error) {
-	return fsv.Type == zfs.Snapshot && strings.HasPrefix(fsv.Name, f.Prefix), nil
+func (f *PrefixFilter) Filter(fsv zfs.FilesystemVersion) (accept bool, err error) {
+	fstypeMatches := (!f.fstypeSet || fsv.Type == f.fstype)
+	prefixMatches := strings.HasPrefix(fsv.Name, f.prefix)
+	return fstypeMatches && prefixMatches, nil
 }
diff --git a/cmd/config_job_local.go b/cmd/config_job_local.go
index c95e924..c6a7f6d 100644
--- a/cmd/config_job_local.go
+++ b/cmd/config_job_local.go
@@ -90,7 +90,7 @@ func (j *LocalJob) JobStart(ctx context.Context) {
 	// All local datasets will be passed to its Map() function,
 	// but only those for which a mapping exists will actually be pulled.
 	// We can pay this small performance penalty for now.
-	handler := NewHandler(log.WithField(logTaskField, "handler"), localPullACL{}, &PrefixSnapshotFilter{j.SnapshotPrefix})
+	handler := NewHandler(log.WithField(logTaskField, "handler"), localPullACL{}, NewPrefixFilter(j.SnapshotPrefix))
 
 	registerEndpoints(local, handler)
 
diff --git a/cmd/config_job_source.go b/cmd/config_job_source.go
index 69ddecd..a96b3ae 100644
--- a/cmd/config_job_source.go
+++ b/cmd/config_job_source.go
@@ -164,7 +164,7 @@ outer:
 			}
 
 			// construct connection handler
-			handler := NewHandler(log, j.Filesystems, &PrefixSnapshotFilter{j.SnapshotPrefix})
+			handler := NewHandler(log, j.Filesystems, NewPrefixFilter(j.SnapshotPrefix))
 
 			// handle connection
 			rpcServer := rpc.NewServer(rwc)
diff --git a/cmd/prune.go b/cmd/prune.go
index 419223c..a59cd00 100644
--- a/cmd/prune.go
+++ b/cmd/prune.go
@@ -46,7 +46,8 @@ func (p *Pruner) Run(ctx context.Context) (r []PruneResult, err error) {
 
 		log := log.WithField(logFSField, fs.ToString())
 
-		fsversions, err := zfs.ZFSListFilesystemVersions(fs, &PrefixSnapshotFilter{p.SnapshotPrefix})
+		snapshotFilter := NewTypedPrefixFilter(p.SnapshotPrefix, zfs.Snapshot)
+		fsversions, err := zfs.ZFSListFilesystemVersions(fs, snapshotFilter)
 		if err != nil {
 			log.WithError(err).Error("error listing filesytem versions")
 			continue