Simple file versioning (fixes #218)

3 files changed, 104 insertions, 0 deletions

diff --git a/versioner/debug.go b/versioner/debug.go
new file mode 100644
index 0000000000..6b5fda4273
--- /dev/null
+++ b/versioner/debug.go
@@ -0,0 +1,13 @@
+package versioner
+
+import (
+	"os"
+	"strings"
+
+	"github.com/calmh/syncthing/logger"
+)
+
+var (
+	debug = strings.Contains(os.Getenv("STTRACE"), "versioner") || os.Getenv("STTRACE") == "all"
+	l     = logger.DefaultLogger
+)
diff --git a/versioner/simple.go b/versioner/simple.go
new file mode 100644
index 0000000000..c1f36eb485
--- /dev/null
+++ b/versioner/simple.go
@@ -0,0 +1,84 @@
+package versioner
+
+import (
+	"os"
+	"path/filepath"
+	"sort"
+	"strconv"
+	"time"
+
+	"github.com/calmh/syncthing/osutil"
+)
+
+func init() {
+	// Register the constructor for this type of versioner with the name "simple"
+	Factories["simple"] = NewSimple
+}
+
+// The type holds our configuration
+type Simple struct {
+	keep int
+}
+
+// The constructor function takes a map of parameters and creates the type.
+func NewSimple(params map[string]string) Versioner {
+	keep, err := strconv.Atoi(params["keep"])
+	if err != nil {
+		keep = 5 // A reasonable default
+	}
+
+	s := Simple{
+		keep: keep,
+	}
+
+	if debug {
+		l.Debugf("instantiated %#v", s)
+	}
+	return s
+}
+
+// Move away the named file to a version archive. If this function returns
+// nil, the named file does not exist any more (has been archived).
+func (v Simple) Archive(path string) error {
+	_, err := os.Stat(path)
+	if err != nil && os.IsNotExist(err) {
+		return nil
+	}
+
+	if debug {
+		l.Debugln("archiving", path)
+	}
+
+	file := filepath.Base(path)
+	dir := filepath.Join(filepath.Dir(path), ".stversions")
+	err = os.MkdirAll(dir, 0755)
+	if err != nil && !os.IsExist(err) {
+		return err
+	} else {
+		osutil.HideFile(dir)
+	}
+
+	ver := file + "~" + time.Now().Format("20060102-150405")
+	err = osutil.Rename(path, filepath.Join(dir, ver))
+	if err != nil {
+		return err
+	}
+
+	versions, err := filepath.Glob(filepath.Join(dir, file+"~*"))
+	if err != nil {
+		l.Warnln(err)
+		return nil
+	}
+
+	if len(versions) > v.keep {
+		sort.Strings(versions)
+		for _, toRemove := range versions[:len(versions)-v.keep] {
+			err = os.Remove(toRemove)
+			if err != nil {
+				l.Warnln(err)
+			}
+		}
+	}
+
+	return nil
+}
diff --git a/versioner/versioner.go b/versioner/versioner.go
new file mode 100644
index 0000000000..19cb7c71c8
--- /dev/null
+++ b/versioner/versioner.go
@@ -0,0 +1,7 @@
+package versioner
+
+type Versioner interface {
+	Archive(path string) error
+}
+
+var Factories = map[string]func(map[string]string) Versioner{}