Refactor log record parsing to work with no allocations.

pkg/log/query.go

@@ -44,24 +44,73 @@ type existence struct{}
 
 var (
 	exister      = struct{}{}
-	spaceByte = []byte(" ")
-	str2type  = map[string]TxType{
-		"sess":  Sess,
-		"req":   Req,
-		"bereq": BeReq,
-	}
-	str2reason = map[string]Reason{
-		"HTTP/1":  HTTP1,
-		"rxreq":   RxReq,
-		"esi":     ESI,
-		"restart": Restart,
-		"pass":    Pass,
-		"fetch":   Fetch,
-		"bgfetch": BgFetch,
-		"pipe":    Pipe,
-	}
+	sessBytes    = []byte("ess")
+	reqBytes     = []byte("eq")
+	bereqBytes   = []byte("ereq")
+	http1Bytes   = []byte("TTP/1")
+	rxreqBytes   = []byte("xreq")
+	esiBytes     = []byte("si")
+	restartBytes = []byte("estart")
+	passBytes    = []byte("ass")
+	fetchBytes   = []byte("etch")
+	bgFetchBytes = []byte("gfetch")
+	pipeBytes    = []byte("ipe")
 )
 
+func bytes2Type(b []byte) (TxType, bool) {
+	switch b[0] {
+	case byte('s'):
+		if bytes.Equal(b[1:], sessBytes) {
+			return Sess, true
+		}
+	case byte('r'):
+		if bytes.Equal(b[1:], reqBytes) {
+			return Req, true
+		}
+	case byte('b'):
+		if bytes.Equal(b[1:], bereqBytes) {
+			return BeReq, true
+		}
+	}
+	return TxUnknown, false
+}
+
+func bytes2Reason(b []byte) (Reason, bool) {
+	switch b[0] {
+	case byte('H'):
+		if bytes.Equal(b[1:], http1Bytes) {
+			return HTTP1, true
+		}
+	case byte('r'):
+		if bytes.Equal(b[1:], rxreqBytes) {
+			return RxReq, true
+		}
+		if bytes.Equal(b[1:], restartBytes) {
+			return Restart, true
+		}
+	case byte('e'):
+		if bytes.Equal(b[1:], esiBytes) {
+			return ESI, true
+		}
+	case byte('p'):
+		if bytes.Equal(b[1:], passBytes) {
+			return Pass, true
+		}
+		if bytes.Equal(b[1:], pipeBytes) {
+			return Pipe, true
+		}
+	case byte('f'):
+		if bytes.Equal(b[1:], fetchBytes) {
+			return Fetch, true
+		}
+	case byte('b'):
+		if bytes.Equal(b[1:], bgFetchBytes) {
+			return BgFetch, true
+		}
+	}
+	return ReasonUnknown, false
+}
+
 type grpNode struct {
 	children []uint32
 	vxid     uint32
@@ -137,33 +186,43 @@ func (c *Cursor) NewQuery(grp Grouping, query string) (*Query, error) {
 
 // Parses a Begin or Link record for the purposes of grouping
 func (q *Query) parseRec(payload Payload) (TxType, uint32, Reason, error) {
-	flds := bytes.Split(payload, spaceByte)
-	if len(flds) != 3 {
-		// XXX
+	min, max, ok := fieldNDelims(payload, 0)
+	if !ok {
+		// XXX error handling
 		return TxUnknown, 0, ReasonUnknown, nil
 	}
-	txtype, exists := str2type[string(flds[0])]
-	if !exists {
-		// XXX
+	txtype, ok := bytes2Type(payload[min:max])
+	if !ok {
+		// XXX error handling
 		return TxUnknown, 0, ReasonUnknown, nil
 	}
-	vxid, ok := atoUint32(flds[1])
+	min, max, ok = fieldNDelims(payload, 1)
 	if !ok {
-		// XXX
+		// XXX error handling
 		return txtype, 0, ReasonUnknown, nil
 	}
-	reason, exists := str2reason[string(flds[2])]
-	if !exists {
-		// XXX
+	vxid, ok := atoUint32(payload[min:max])
+	if !ok {
+		// XXX error handling
+		return txtype, 0, ReasonUnknown, nil
+	}
+	min, max, ok = fieldNDelims(payload, 2)
+	if !ok {
+		// XXX error handling
 		return txtype, vxid, ReasonUnknown, nil
 	}
+	reason, ok := bytes2Reason(payload[min:max])
+	if !ok {
+		// XXX error handling
+		return TxUnknown, vxid, ReasonUnknown, nil
+	}
 	return txtype, vxid, reason, nil
 }
 
 func (q *Query) link(pvxid uint32, vxid uint32) {
 	child, cexists := q.grpNodes[vxid]
 	if !cexists {
-		child = grpNode{ vxid: vxid }
+		child = grpNode{vxid: vxid}
 	}
 	child.pvxid = pvxid
 	q.grpNodes[vxid] = child
@@ -172,7 +231,7 @@ func (q *Query) link(pvxid uint32, vxid uint32) {
 	}
 	parent, pexists := q.grpNodes[pvxid]
 	if !pexists {
-		parent = grpNode{ vxid: pvxid }
+		parent = grpNode{vxid: pvxid}
 	}
 	found := false
 	for _, xid := range parent.children {