stream/mts/encoder.go: implemented metadata receiver functions: Add, Get, All and Delete

stream/mts/encoder.go

@@ -29,6 +29,8 @@ LICENSE
 package mts
 
 import (
+	"errors"
+	"fmt"
 	"io"
 	"sync"
 	"time"
@@ -88,43 +90,53 @@ const (
 	psiSndCnt = 7
 )
 
-// timeLocation holds time and location data
-type timeLocation struct {
-	mu       sync.RWMutex
-	time     uint64
-	location string
+// global Meta
+var meta Meta
+
+type Meta struct {
+	mu   sync.RWMutex
+	data map[string]string
 }
 
-// SetTimeStamp sets the time field of a TimeLocation.
-func (tl *timeLocation) SetTimeStamp(t uint64) {
-	tl.mu.Lock()
-	tl.time = t
-	tl.mu.Unlock()
+// Add adds metadata with key and val, if already exists return error
+func (m *Meta) Add(key, val string) error {
+	m.mu.Lock()
+	if _, exists := m.data[key]; !exists {
+		return errors.New(fmt.Sprintf("Metadata for: %v already exists", key))
+	}
+	m.data[key] = val
+	m.mu.Unlock()
+	return nil
 }
 
-// GetTimeStamp returns the location of a TimeLocation.
-func (tl *timeLocation) TimeStamp() uint64 {
-	tl.mu.RLock()
-	t := tl.time
-	tl.mu.RUnlock()
-	return t
+// All returns the a copy of the map containing the meta data
+func (m *Meta) All() map[string]string {
+	var cpy map[string]string
+	for k, v := range m.data {
+		cpy[k] = v
+	}
+	return cpy
 }
 
-// SetLocation sets the location of a TimeLocation.
-func (tl *timeLocation) SetLocation(l string) {
-	tl.mu.Lock()
-	tl.location = l
-	tl.mu.Unlock()
+// Get returns the meta data for the passed key
+func (m *Meta) Get(key string) (string, error) {
+	val, ok := m.data[key]
+	if !ok {
+		return "", errors.New("Key does not exist in metadata map")
+	}
+	return val, nil
 }
 
-// GetLocation returns the location of a TimeLocation.
-func (tl *timeLocation) Location() string {
-	tl.mu.RLock()
-	l := tl.location
-	tl.mu.RUnlock()
-	return l
+// Remove deletes a meta entry in the map and returns error if it doesn’t exist
+func (m *Meta) Delete(key string) error {
+	if _, ok := m.data[key]; ok {
+		delete(m.data, key)
+		return nil
+	}
+	return errors.New("Trying to delete map entry that doesn't exist")
 }
 
+// updateMeta ...
 func updateMeta(b []byte) error {
 	var p psi.PSIBytes
 	p = b
@@ -136,10 +148,6 @@ func updateMeta(b []byte) error {
 	return nil
 }
 
-// MetData will hold time and location data which may be set externally if
-// this data is available. It is then inserted into mpegts packets outputted.
-var MetaData timeLocation
-
 var (
 	patTable = standardPat.Bytes()
 	pmtTable = standardPmt.Bytes()