Server Event Optimizations (#116)

system/utils.go

@@ -8,7 +8,6 @@ import (
 	"fmt"
 	"io"
 	"strconv"
-	"strings"
 	"sync"
 	"time"
 
@@ -38,14 +37,14 @@ func MustInt(v string) int {
 	return i
 }
 
-func ScanReader(r io.Reader, callback func(line string)) error {
+func ScanReader(r io.Reader, callback func(line []byte)) error {
 	br := bufio.NewReader(r)
 	// Avoid constantly re-allocating memory when we're flooding lines through this
 	// function by using the same buffer for the duration of the call and just truncating
 	// the value back to 0 every loop.
-	var str strings.Builder
+	buf := &bytes.Buffer{}
 	for {
-		str.Reset()
+		buf.Reset()
 		var err error
 		var line []byte
 		var isPrefix bool
@@ -57,7 +56,7 @@ func ScanReader(r io.Reader, callback func(line string)) error {
 			// in line with that it thinks is the terminal size. Those returns break a lot of output handling,
 			// so we'll just replace them with proper new-lines and then split it later and send each line as
 			// its own event in the response.
-			str.Write(bytes.Replace(line, cr, crr, -1))
+			buf.Write(bytes.Replace(line, cr, crr, -1))
 			// Finish this loop and begin outputting the line if there is no prefix (the line fit into
 			// the default buffer), or if we hit the end of the line.
 			if !isPrefix || err == io.EOF {
@@ -71,8 +70,9 @@ func ScanReader(r io.Reader, callback func(line string)) error {
 		}
 		// Publish the line for this loop. Break on new-line characters so every line is sent as a single
 		// output event, otherwise you get funky handling in the browser console.
-		for _, line := range strings.Split(str.String(), "\r\n") {
-			callback(line)
+		s := bufio.NewScanner(buf)
+		for s.Scan() {
+			callback(s.Bytes())
 		}
 		// If the error we got previously that lead to the line being output is an io.EOF we want to
 		// exit the entire looping process.