Remove the goroutines from the shortcode lexer

It was clever, but storing the items in a slice is faster -- and it gives room to more goroutines in other places.

```bash
benchmark                     old ns/op     new ns/op     delta
BenchmarkShortcodeLexer-4     180173        79614         -55.81%

benchmark                     old allocs     new allocs     delta
BenchmarkShortcodeLexer-4     309            328            +6.15%

benchmark                     old bytes     new bytes     delta
BenchmarkShortcodeLexer-4     35456         47008         +32.58%
```

diff --git a/hugolib/shortcodeparser.go b/hugolib/shortcodeparser.go
index bdbd3ae50abf7bbb05b18ea7521167638f68fd4d..18b1454cdb658a2e45ffe0bc0e95ffe8f5984707 100644 (file)
--- a/hugolib/shortcodeparser.go
+++ b/hugolib/shortcodeparser.go
@@ -159,7 +159,7 @@ type pagelexer struct {
        openShortcodes     map[string]bool // set of shortcodes in open state
 
        // items delivered to client
-       items chan item
+       items []item
 }
 
 // note: the input position here is normally 0 (start), but
@@ -172,9 +172,9 @@ func newShortcodeLexer(name, input string, inputPosition pos) *pagelexer {
                currRightDelimItem: tRightDelimScNoMarkup,
                pos:                inputPosition,
                openShortcodes:     make(map[string]bool),
-               items:              make(chan item),
+               items:              make([]item, 0, 5),
        }
-       go lexer.runShortcodeLexer()
+       lexer.runShortcodeLexer()
        return lexer
 }
 
@@ -184,8 +184,6 @@ func (l *pagelexer) runShortcodeLexer() {
        for l.state = lexTextOutsideShortcodes; l.state != nil; {
                l.state = l.state(l)
        }
-
-       close(l.items)
 }
 
 // state functions
@@ -227,7 +225,7 @@ func (l *pagelexer) backup() {
 
 // sends an item back to the client.
 func (l *pagelexer) emit(t itemType) {
-       l.items <- item{t, l.start, l.input[l.start:l.pos]}
+       l.items = append(l.items, item{t, l.start, l.input[l.start:l.pos]})
        l.start = l.pos
 }
 
@@ -239,7 +237,7 @@ func (l *pagelexer) ignoreEscapesAndEmit(t itemType) {
                }
                return r
        }, l.input[l.start:l.pos])
-       l.items <- item{t, l.start, val}
+       l.items = append(l.items, item{t, l.start, val})
        l.start = l.pos
 }
 
@@ -260,13 +258,14 @@ func (l *pagelexer) lineNum() int {
 
 // nil terminates the parser
 func (l *pagelexer) errorf(format string, args ...interface{}) stateFunc {
-       l.items <- item{tError, l.start, fmt.Sprintf(format, args...)}
+       l.items = append(l.items, item{tError, l.start, fmt.Sprintf(format, args...)})
        return nil
 }
 
 // consumes and returns the next item
 func (l *pagelexer) nextItem() item {
-       item := <-l.items
+       item := l.items[0]
+       l.items = l.items[1:]
        l.lastPos = item.pos
        return item
 }