stream/mts: moved meta.go and meta_test.go into meta package

This commit is contained in:
saxon 2019-01-31 21:23:06 +10:30
parent 9011c090d9
commit 10343375a3
2 changed files with 295 additions and 0 deletions

145
stream/mts/meta/meta.go Normal file
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/*
NAME
meta.go
DESCRIPTION
See Readme.md
AUTHOR
Saxon Nelson-Milton <saxon@ausocean.org>
LICENSE
meta.go is Copyright (C) 2017-2019 the Australian Ocean Lab (AusOcean)
It is free software: you can redistribute it and/or modify them
under the terms of the GNU General Public License as published by the
Free Software Foundation, either version 3 of the License, or (at your
option) any later version.
It is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License
along with revid in gpl.txt. If not, see http://www.gnu.org/licenses.
*/
package mts
import (
"errors"
"strings"
"sync"
)
const headSize = 4
const (
majVer = 1
minVer = 0
)
const (
dataLenIdx1 = 2
dataLenIdx2 = 3
)
var (
errKeyAbsent = errors.New("Key does not exist in map")
)
type Metadata struct {
mu sync.RWMutex
data map[string]string
enc []byte
}
func NewMeta() *Metadata {
return &Metadata{
data: make(map[string]string),
enc: []byte{
0x00, // Reserved byte
(majVer << 4) | minVer, // MS and LS versions
0x00, // Data len byte1
0x00, // Data len byte2
},
}
}
// Add adds metadata with key and val, if already exists return error
func (m *Metadata) Add(key, val string) {
m.mu.Lock()
m.data[key] = val
m.mu.Unlock()
}
// All returns the a copy of the map containing the meta data
func (m *Metadata) All() map[string]string {
m.mu.Lock()
cpy := make(map[string]string)
for k, v := range m.data {
cpy[k] = v
}
m.mu.Unlock()
return cpy
}
// Get returns the meta data for the passed key
func (m *Metadata) Get(key string) (string, error) {
m.mu.Lock()
val, ok := m.data[key]
m.mu.Unlock()
if !ok {
return "", errKeyAbsent
}
return val, nil
}
// Remove deletes a meta entry in the map and returns error if it doesnt exist
func (m *Metadata) Delete(key string) error {
m.mu.Lock()
defer m.mu.Unlock()
if _, ok := m.data[key]; ok {
delete(m.data, key)
return nil
}
return errKeyAbsent
}
// Encode takes the meta data map and encods into a byte slice with header
// describing the version, length of data and data in TSV format.
func (m *Metadata) Encode() []byte {
m.enc = m.enc[:headSize]
// 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++
entry += k + "=" + v
if i < len(m.data) {
entry += "\t"
}
}
m.enc = append(m.enc, []byte(entry)...)
// 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)
return m.enc
}
func ReadFrom(d []byte, key string) (string, error) {
entries := strings.Split(string(d), "\t")
for _, entry := range entries {
kv := strings.Split(entry, "=")
if kv[0] == key {
return kv[1], nil
}
}
return "", errors.New("could not find key in metadata")
}

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/*
NAME
meta_test.go
DESCRIPTION
See Readme.md
AUTHOR
Saxon Nelson-Milton <saxon@ausocean.org>
LICENSE
meta_test.go is Copyright (C) 2017-2019 the Australian Ocean Lab (AusOcean)
It is free software: you can redistribute it and/or modify them
under the terms of the GNU General Public License as published by the
Free Software Foundation, either version 3 of the License, or (at your
option) any later version.
It is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License
along with revid in gpl.txt. If not, see http://www.gnu.org/licenses.
*/
package mts
import (
"bytes"
"errors"
"reflect"
"testing"
)
const (
tstKey1 = "loc"
tstData1 = "a,b,c"
tstKey2 = "ts"
tstData2 = "12345678"
tstData3 = "d,e,f"
)
// TestAddAndGet ensures that we can add metadata and then successfully get it.
func TestAddAndGet(t *testing.T) {
meta := NewMeta()
meta.Add(tstKey1, tstData1)
meta.Add(tstKey2, tstData2)
errors.New("Trying to delete map entry that doesn't exist")
if data, err := meta.Get(tstKey1); err != nil {
t.Errorf("Could not get data for key: loc: %v", err.Error())
if data != tstData1 {
t.Errorf("Did not get expected data")
}
}
if data, err := meta.Get(tstKey2); err != nil {
t.Errorf("Could not get data for key: ts: %v", err.Error())
if data != tstData2 {
t.Errorf("Did not get expected data")
}
}
}
// TestUpdate checks that we can use Meta.Add to actually update metadata
// if it already exists in the Meta map.
func TestUpdate(t *testing.T) {
meta := NewMeta()
meta.Add(tstKey1, tstData1)
meta.Add(tstKey1, tstData3)
if data, err := meta.Get(tstKey1); err != nil {
t.Errorf("Did not expect err: %v", err.Error())
if data != tstData2 {
t.Errorf("Data did not correctly update for key \"loc\"")
}
}
}
// TestAll ensures we can get a correct map using Meta.All() after adding some data
func TestAll(t *testing.T) {
meta := NewMeta()
tstMap := map[string]string{
tstKey1: tstData1,
tstKey2: tstData2,
}
meta.Add(tstKey1, tstData1)
meta.Add(tstKey2, tstData2)
metaMap := meta.All()
if !reflect.DeepEqual(metaMap, tstMap) {
t.Errorf("Map not correct. Got: %v, want: %v", metaMap, tstMap)
}
}
// TestGetAbsentKey ensures that we get the expected error when we try to get with
// key that does not yet exist in the Meta map.
func TestGetAbsentKey(t *testing.T) {
meta := NewMeta()
if _, err := meta.Get(tstKey1); err != errKeyAbsent {
t.Errorf("Did not get expected err: %v", errKeyAbsent.Error())
}
}
// TestDelete ensures we can remove a data entry in the Meta map.
func TestDelete(t *testing.T) {
meta := NewMeta()
meta.Add(tstKey1, tstData1)
if err := meta.Delete(tstKey1); err != nil {
t.Errorf("Did not expect error: %v", err.Error())
}
if _, err := meta.Get(tstKey1); err != errKeyAbsent {
t.Errorf("Did not get expected err: %v", errKeyAbsent.Error())
}
}
// TestDeleteAbsentKey checks that we get an expected error when we try to delete
// an entry in the Meta map that doesn't exist.
func TestDeleteAbsentKey(t *testing.T) {
meta := NewMeta()
if err := meta.Delete(tstKey1); err != errKeyAbsent {
t.Errorf("Did not get expected err: %v", errKeyAbsent.Error())
}
}
// TestEncode checks that we're getting the correct byte slice from Meta.Encode().
func TestEncode(t *testing.T) {
meta := NewMeta()
meta.Add(tstKey1, tstData1)
meta.Add(tstKey2, tstData2)
dataLen := len(tstKey1+tstData1+tstKey2+tstData2) + 3
expectedOut := []byte{
0x00,
0x10,
byte(dataLen >> 8),
byte(dataLen),
}
expectedOut = append(expectedOut, []byte(
tstKey1+"="+tstData1+"\t"+
tstKey2+"="+tstData2)...)
got := meta.Encode()
if !bytes.Equal(expectedOut, got) {
t.Errorf("Did not get expected out. \nGot : %v \nwant: %v", got, expectedOut)
}
}