stream/mts/meta: using order slice so that encoded order reamins consistent with order that we added metadata. And also now using binary.BigEndian.PutUint16() to encode len into metdata rather than doing ugly byte manipulation

This commit is contained in:
saxon 2019-02-05 12:55:32 +10:30
parent ad25785b77
commit 834625a9f7
1 changed files with 16 additions and 12 deletions

View File

@ -45,8 +45,7 @@ const (
// Indices of bytes for uint16 metadata length.
const (
dataLenIdx1 = 2
dataLenIdx2 = 3
dataLenIdx = 2
)
var (
@ -60,6 +59,7 @@ var (
type Metadata struct {
mu sync.RWMutex
data map[string]string
order []string
enc []byte
}
@ -80,6 +80,7 @@ func New() *Metadata {
func (m *Metadata) Add(key, val string) {
m.mu.Lock()
m.data[key] = val
m.order = append(m.order, key)
m.mu.Unlock()
}
@ -111,6 +112,12 @@ func (m *Metadata) Delete(key string) error {
defer m.mu.Unlock()
if _, ok := m.data[key]; ok {
delete(m.data, key)
for i, k := range m.order {
if k == key {
m.order = append(m.order[:i], m.order[i+1:]...)
break
}
}
return nil
}
return errKeyAbsent
@ -123,12 +130,11 @@ func (m *Metadata) Encode() []byte {
// Iterate over map and append entries, only adding tab if we're not on the
// last entry.
var i int
var entry string
for k, v := range m.data {
i++
for i, k := range m.order {
v := m.data[k]
entry += k + "=" + v
if i < len(m.data) {
if i+1 < len(m.data) {
entry += "\t"
}
}
@ -136,9 +142,7 @@ func (m *Metadata) Encode() []byte {
// Calculate and set data length in encoded meta header.
dataLen := len(m.enc[headSize:])
m.enc[dataLenIdx1] = byte(dataLen >> 8)
m.enc[dataLenIdx2] = byte(dataLen)
binary.BigEndian.PutUint16(m.enc[dataLenIdx:dataLenIdx+2], uint16(dataLen))
return m.enc
}