Fix parsing deadlock (#57)

Parser will deadlock if hitting `if len(pj.containingScopeOffset) != 0` before returning, since 
the stream is done, but we return false.

Return status and done status separately.

Author: klauspost

parse_json_amd64.go

@@ -77,12 +77,14 @@ func (pj *internalParsedJson) parseMessage(msg []byte, ndjson bool) (err error)
 		wg.Add(1)
 		go func() {
 			defer wg.Done()
-			if !pj.unifiedMachine() {
+			if ok, done := pj.unifiedMachine(); !ok {
 				err = errors.New("Bad parsing while executing stage 2")
 				// Keep consuming...
-				for idx := range pj.indexChans {
-					if idx.index == -1 {
-						break
+				if !done {
+					for idx := range pj.indexChans {
+						if idx.index == -1 {
+							break
+						}
 					}
 				}
 			}
@@ -101,7 +103,7 @@ func (pj *internalParsedJson) parseMessage(msg []byte, ndjson bool) (err error)
 			}
 			return errors.New("Failed to find all structural indices for stage 1")
 		}
-		if !pj.unifiedMachine() {
+		if ok, _ := pj.unifiedMachine(); !ok {
 			// drain the channel until empty
 			for {
 				select {

parse_json_amd64_test.go

@@ -637,26 +637,31 @@ func benchmarkParseNumber(b *testing.B, neg int) {
 }
 
 func BenchmarkParseNumberFloat(b *testing.B) {
+	b.SetBytes(1)
 	for i := 0; i < b.N; i++ {
 		parseNumber([]byte("339.7784:"))
 	}
 }
 
 func BenchmarkParseAtof64FloatGolang(b *testing.B) {
+	b.SetBytes(1)
 	for i := 0; i < b.N; i++ {
 		strconv.ParseFloat("339.7784", 64)
 	}
 }
 
 func BenchmarkParseNumberFloatExp(b *testing.B) {
+	b.SetBytes(1)
 	for i := 0; i < b.N; i++ {
 		parseNumber([]byte("-5.09e75:"))
 	}
 }
 
 func BenchmarkParseNumberBig(b *testing.B) {
+	b.SetBytes(1)
+	x := []byte("123456789123456789123456789:")
 	for i := 0; i < b.N; i++ {
-		parseNumber([]byte("123456789123456789123456789:"))
+		parseNumber(x)
 	}
 }
 

stage2_build_tape_amd64.go

@@ -157,11 +157,10 @@ func isValidNullAtom(buf []byte) bool {
 	return false
 }
 
-func (pj *internalParsedJson) unifiedMachine() bool {
+func (pj *internalParsedJson) unifiedMachine() (ok, done bool) {
 	buf := pj.Message
 	const addOneForRoot = 1
 
-	done := false
 	idx := ^uint64(0)   // location of the structural character in the input (buf)
 	offset := uint64(0) // used to contain last element of containing_scope_offset
 
@@ -433,17 +432,17 @@ succeed:
 
 	// Sanity checks
 	if len(pj.containingScopeOffset) != 0 {
-		return false
+		return false, done
 	}
 
 	pj.annotate_previousloc(offset>>retAddressShift, pj.get_current_loc()+addOneForRoot)
 	pj.write_tape(offset>>retAddressShift, 'r') // r is root
 
 	pj.isvalid = true
-	return true
+	return true, done
 
 fail:
-	return false
+	return false, done
 }
 
 // structural chars here are