directory structure change to work with glide

glide has its own requirements. My previous workaround caused me some
code checkin errors. Need to fix this.

weed/storage/volume_ttl.go

@@ -0,0 +1,135 @@
+package storage
+
+import (
+	"strconv"
+)
+
+const (
+	//stored unit types
+	Empty byte = iota
+	Minute
+	Hour
+	Day
+	Week
+	Month
+	Year
+)
+
+type TTL struct {
+	count byte
+	unit  byte
+}
+
+var EMPTY_TTL = &TTL{}
+
+// translate a readable ttl to internal ttl
+// Supports format example:
+// 3m: 3 minutes
+// 4h: 4 hours
+// 5d: 5 days
+// 6w: 6 weeks
+// 7M: 7 months
+// 8y: 8 years
+func ReadTTL(ttlString string) (*TTL, error) {
+	if ttlString == "" {
+		return EMPTY_TTL, nil
+	}
+	ttlBytes := []byte(ttlString)
+	unitByte := ttlBytes[len(ttlBytes)-1]
+	countBytes := ttlBytes[0 : len(ttlBytes)-1]
+	if '0' <= unitByte && unitByte <= '9' {
+		countBytes = ttlBytes
+		unitByte = 'm'
+	}
+	count, err := strconv.Atoi(string(countBytes))
+	unit := toStoredByte(unitByte)
+	return &TTL{count: byte(count), unit: unit}, err
+}
+
+// read stored bytes to a ttl
+func LoadTTLFromBytes(input []byte) (t *TTL) {
+	return &TTL{count: input[0], unit: input[1]}
+}
+
+// read stored bytes to a ttl
+func LoadTTLFromUint32(ttl uint32) (t *TTL) {
+	input := make([]byte, 2)
+	input[1] = byte(ttl)
+	input[0] = byte(ttl >> 8)
+	return LoadTTLFromBytes(input)
+}
+
+// save stored bytes to an output with 2 bytes
+func (t *TTL) ToBytes(output []byte) {
+	output[0] = t.count
+	output[1] = t.unit
+}
+
+func (t *TTL) ToUint32() (output uint32) {
+	output = uint32(t.count) << 8
+	output += uint32(t.unit)
+	return output
+}
+
+func (t *TTL) String() string {
+	if t == nil || t.count == 0 {
+		return ""
+	}
+	if t.unit == Empty {
+		return ""
+	}
+	countString := strconv.Itoa(int(t.count))
+	switch t.unit {
+	case Minute:
+		return countString + "m"
+	case Hour:
+		return countString + "h"
+	case Day:
+		return countString + "d"
+	case Week:
+		return countString + "w"
+	case Month:
+		return countString + "M"
+	case Year:
+		return countString + "y"
+	}
+	return ""
+}
+
+func toStoredByte(readableUnitByte byte) byte {
+	switch readableUnitByte {
+	case 'm':
+		return Minute
+	case 'h':
+		return Hour
+	case 'd':
+		return Day
+	case 'w':
+		return Week
+	case 'M':
+		return Month
+	case 'y':
+		return Year
+	}
+	return 0
+}
+
+func (t TTL) Minutes() uint32 {
+	switch t.unit {
+	case Empty:
+		return 0
+	case Minute:
+		return uint32(t.count)
+	case Hour:
+		return uint32(t.count) * 60
+	case Day:
+		return uint32(t.count) * 60 * 24
+	case Week:
+		return uint32(t.count) * 60 * 24 * 7
+	case Month:
+		return uint32(t.count) * 60 * 24 * 31
+	case Year:
+		return uint32(t.count) * 60 * 24 * 365
+	}
+	return 0
+}