revid: cleaned up documentation in senders.go and mtsSender_test.go

revid/mtsSender_test.go

@@ -51,6 +51,8 @@ const (
 	rTimeout      = 10 * time.Millisecond
 )
 
+// sender simulates sending of video data, creating discontinuities if
+// testDiscontinuities is set to true.
 type sender struct {
 	buf                 [][]byte
 	testDiscontinuities bool
@@ -58,6 +60,8 @@ type sender struct {
 	currentPkt          int
 }
 
+// send takes d and neglects if testDiscontinuities is true, returning an error,
+// otherwise d is appended to senders buf.
 func (ts *sender) send(d []byte) error {
 	if ts.testDiscontinuities && ts.currentPkt == ts.discontinuityAt {
 		ts.currentPkt++
@@ -70,6 +74,8 @@ func (ts *sender) send(d []byte) error {
 	return nil
 }
 
+// log implements the required logging func for some of the structs in use
+// within tests.
 func log(lvl int8, msg string, args ...interface{}) {
 	var l string
 	switch lvl {
@@ -91,32 +97,38 @@ func log(lvl int8, msg string, args ...interface{}) {
 	fmt.Printf(msg, args)
 }
 
+// tstPacker implements io.Writer and handles the writing of data to the
+// ringBuffer used in tests.
 type tstPacker struct {
 	rb *ring.Buffer
 }
 
+// Write writes to tstPacker's ringBuffer.
 func (p *tstPacker) Write(d []byte) (int, error) {
 	n, err := p.rb.Write(d)
 	p.rb.Flush()
 	return n, err
 }
 
+// TestSegment ensures that the mtsSender correctly segments data into clips
+// based on positioning of PSI in the mtsEncoder's output stream.
 func TestSegment(t *testing.T) {
 	mts.Meta = meta.New()
-	// Create ringbuffer tst sender, loadsender and the mpegts encoder
+	// Create ringBuffer, sender, loadsender and the MPEGTS encoder.
 	rb := ring.NewBuffer(rbSize, rbElementSize, wTimeout)
 	tstSender := &sender{}
 	loadSender := newMtsSender(tstSender, log)
 	packer := &tstPacker{rb: rb}
 	encoder := mts.NewEncoder(packer, 25)
 
-	// Turn time based psi writing off for encoder
+	// Turn time based PSI writing off for encoder.
 	const psiSendCount = 10
 	encoder.TimeBasedPsi(false, psiSendCount)
 
 	const noOfPacketsToWrite = 100
 	for i := 0; i < noOfPacketsToWrite; i++ {
-		// Our payload will just be packet no
+		// Insert a payload so that we check that the segmentation works correctly
+		// in this regard. Packet no will be used.
 		encoder.Encode([]byte{byte(i)})
 		rb.Flush()
 
@@ -143,13 +155,13 @@ func TestSegment(t *testing.T) {
 	expectData := 0
 	for clipNo, clip := range result {
 		t.Logf("Checking clip: %v\n", clipNo)
-		// Check that the clip is the right length
+		// Check that the clip is of expected length.
 		clipLen := len(clip)
 		if clipLen != psiSendCount*mts.PacketSize {
 			t.Fatalf("Clip %v is not correct length. Got: %v Want: %v\n Clip: %v\n", clipNo, clipLen, psiSendCount*mts.PacketSize, clip)
 		}
 
-		// Also check that the first packet is a PAT
+		// Also check that the first packet is a PAT.
 		firstPkt := clip[:mts.PacketSize]
 		var pkt [mts.PacketSize]byte
 		copy(pkt[:], firstPkt)
@@ -158,29 +170,28 @@ func TestSegment(t *testing.T) {
 			t.Fatalf("First packet of clip %v is not pat, but rather: %v\n", clipNo, pid)
 		}
 
-		// Check that the clip data is okay
+		// Check that the clip data is okay.
 		for i := 0; i < len(clip); i += mts.PacketSize {
 			firstPkt := clip[i : i+mts.PacketSize]
 			copy(pkt[:], firstPkt)
 			p := (*packet.Packet)(&pkt)
 			pid := p.PID()
 			if pid == mts.VideoPid {
-				// Mts payload
 				payload, err := p.Payload()
 				if err != nil {
 					t.Fatalf("Unexpected err: %v\n", err)
 				}
 
-				// Parse pes from the mts payload
+				// Parse PES from the MTS payload.
 				pes, err := pes.NewPESHeader(payload)
 				if err != nil {
 					t.Fatalf("Unexpected err: %v\n", err)
 				}
 
-				// Get the data from the pes packet and convert to int
+				// Get the data from the PES packet and convert to an int.
 				data := int8(pes.Data()[0])
 
-				// Calc expected data in the pes and then check
+				// Calc expected data in the PES and then check.
 				if data != int8(expectData) {
 					t.Errorf("Did not get expected pkt data. ClipNo: %v, pktNoInClip: %v, Got: %v, want: %v\n", clipNo, i/mts.PacketSize, data, expectData)
 				}
@@ -192,7 +203,7 @@ func TestSegment(t *testing.T) {
 
 func TestSendFailDiscontinuity(t *testing.T) {
 	mts.Meta = meta.New()
-	// Create ringbuffer tst sender, loadsender and the mpegts encoder
+	// Create ringBuffer sender, loadSender and the MPEGTS encoder.
 	rb := ring.NewBuffer(rbSize, rbElementSize, wTimeout)
 	const disconClipNo = 3
 	tstSender := &sender{testDiscontinuities: true, discontinuityAt: disconClipNo}
@@ -200,13 +211,13 @@ func TestSendFailDiscontinuity(t *testing.T) {
 	packer := tstPacker{rb: rb}
 	encoder := mts.NewEncoder(&packer, 25)
 
-	// Turn time based psi writing off for encoder
+	// Turn time based PSI writing off for encoder.
 	const psiSendCount = 10
 	encoder.TimeBasedPsi(false, psiSendCount)
 
 	const noOfPacketsToWrite = 100
 	for i := 0; i < noOfPacketsToWrite; i++ {
-		// Our payload will just be packet no
+		// Our payload will just be packet no.
 		encoder.Encode([]byte{byte(i)})
 		rb.Flush()
 
@@ -229,13 +240,13 @@ func TestSendFailDiscontinuity(t *testing.T) {
 
 	result := tstSender.buf
 
-	// First check that we have less clips
+	// First check that we have less clips as expected.
 	expectedLen := (((noOfPacketsToWrite/psiSendCount)*2 + noOfPacketsToWrite) / psiSendCount) - 1
 	gotLen := len(result)
 	if gotLen != expectedLen {
 		t.Errorf("We don't have one less clip as we should. Got: %v, want: %v\n", gotLen, expectedLen)
 	}
-	// Now check that the discontonuity indicator is set at the disconClip pat
+	// Now check that the discontinuity indicator is set at the discontinuityClip PAT.
 	disconClip := result[disconClipNo]
 	firstPkt := disconClip[:mts.PacketSize]
 	var pkt [mts.PacketSize]byte

revid/senders.go

@@ -45,17 +45,21 @@ import (
 	"github.com/Comcast/gots/packet"
 )
 
+// Sender is intended to provided functionality for the sending of a byte slice
+// to an implemented destination.
 type Sender interface {
+	// send takes the bytes slice d and sends to a particular destination as
+	// implemented.
 	send(d []byte) error
 }
 
-// httpSender implements loadSender for posting HTTP to NetReceiver
+// minimalHttpSender implements Sender for posting HTTP to netreceiver or vidgrind.
 type minimalHttpSender struct {
 	client *netsender.Sender
-
+	log    func(lvl int8, msg string, args ...interface{})
-	log func(lvl int8, msg string, args ...interface{})
 }
 
+// newMinimalHttpSender returns a pointer to a new minimalHttpSender.
 func newMinimalHttpSender(ns *netsender.Sender, log func(lvl int8, msg string, args ...interface{})) *minimalHttpSender {
 	return &minimalHttpSender{
 		client: ns,
@@ -63,6 +67,7 @@ func newMinimalHttpSender(ns *netsender.Sender, log func(lvl int8, msg string, a
 	}
 }
 
+// send takes a bytes slice d and sends to http using s' http client.
 func (s *minimalHttpSender) send(d []byte) error {
 	return httpSend(d, s.client, s.log)
 }
@@ -127,10 +132,10 @@ func (s *fileSender) close() error {
 	return s.file.Close()
 }
 
-// mtsSender provides sending capability specifically for use with
+// mtsSender implemented loadSender and provides sending capability specifically
-// mpegts packetization. It handles the construction of appropriately lengthed
+// for use with MPEGTS packetization. It handles the construction of appropriately
-// clips based on PSI. It also fixes accounts for discontinuities by setting
+// lengthed clips based on PSI. It also fixes accounts for discontinuities by
-// the discontinuity indicator for the first packet of a clip.
+// setting the discontinuity indicator for the first packet of a clip.
 type mtsSender struct {
 	sender    Sender
 	buf       []byte
@@ -143,7 +148,7 @@ type mtsSender struct {
 	curPid    int
 }
 
-// newmtsSender returns a new mtsSender.
+// newMtsSender returns a new mtsSender.
 func newMtsSender(s Sender, log func(lvl int8, msg string, args ...interface{})) *mtsSender {
 	return &mtsSender{
 		sender:   s,
@@ -151,12 +156,13 @@ func newMtsSender(s Sender, log func(lvl int8, msg string, args ...interface{}))
 	}
 }
 
-// load takes a *ring.Chunk and extracts bytes copying into s.pkt for use by the sender.
+// load takes a *ring.Chunk and assigns to s.next, also grabbing it's pid and
+// assigning to s.curPid. s.next if exists is also appended to the sender buf.
 func (s *mtsSender) load(c *ring.Chunk) error {
-	s.chunk = c
 	if s.next != nil {
 		s.buf = append(s.buf, s.next...)
 	}
+	s.chunk = c
 	bytes := s.chunk.Bytes()
 	cpy := make([]byte, len(bytes))
 	copy(cpy, bytes)
@@ -168,8 +174,8 @@ func (s *mtsSender) load(c *ring.Chunk) error {
 	return nil
 }
 
-// send checks the most recently loaded packet and if it is a PAT then the clip
+// send checks the currently loaded paackets PID; if it is a PAT then what is in
-// in s.buf is sent, otherwise the packet is added to s.buf.
+// the mtsSenders buffer is fixed and sent.
 func (s *mtsSender) send() error {
 	if s.curPid == mts.PatPid && len(s.buf) > 0 {
 		err := s.fixAndSend()
@@ -183,8 +189,9 @@ func (s *mtsSender) send() error {
 	return nil
 }
 
-// fixAndSend uses the discontinuity repairer to ensure there is not a
+// fixAndSend checks for discontinuities in the senders buffer and then sends.
-// discontinuity, and if so sets the discontinuity indicator of the PAT packet.
+// If a discontinuity is found the PAT packet at the start of the clip has it's
+// discontintuity indicator set to true.
 func (ms *mtsSender) fixAndSend() error {
 	err := ms.repairer.Repair(ms.buf)
 	if err != nil {
@@ -199,8 +206,8 @@ func (ms *mtsSender) fixAndSend() error {
 
 func (s *mtsSender) close() error { return nil }
 
-// release will set the s.fail flag to fals and clear the buffer if
+// release will set the s.fail flag to false and clear the buffer if
-// the previous send was a fail.
+// the previous send was a fail. The currently loaded chunk is also closed.
 func (s *mtsSender) release() {
 	if s.failed {
 		s.buf = s.buf[:0]