Use Chroma as new default syntax highlighter

If you want to use Pygments, set `pygmentsUseClassic=true` in your site config.

Fixes #3888

1 files changed, 199 insertions, 2 deletions

diff --git a/helpers/pygments_test.go b/helpers/pygments_test.go
index 1fce17859..ee8076c71 100644
--- a/helpers/pygments_test.go
+++ b/helpers/pygments_test.go
@@ -14,12 +14,19 @@
 package helpers
 
 import (
+	"fmt"
+	"reflect"
 	"testing"
 
+	"github.com/alecthomas/chroma/formatters/html"
+
 	"github.com/spf13/viper"
+	"github.com/stretchr/testify/require"
 )
 
 func TestParsePygmentsArgs(t *testing.T) {
+	assert := require.New(t)
+
 	for i, this := range []struct {
 		in                 string
 		pygmentsStyle      string
@@ -38,8 +45,10 @@ func TestParsePygmentsArgs(t *testing.T) {
 		v := viper.New()
 		v.Set("pygmentsStyle", this.pygmentsStyle)
 		v.Set("pygmentsUseClasses", this.pygmentsUseClasses)
+		spec, err := NewContentSpec(v)
+		assert.NoError(err)
 
-		result1, err := parsePygmentsOpts(v, this.in)
+		result1, err := spec.createPygmentsOptionsString(this.in)
 		if b, ok := this.expect1.(bool); ok && !b {
 			if err == nil {
 				t.Errorf("[%d] parsePygmentArgs didn't return an expected error", i)
@@ -58,6 +67,8 @@ func TestParsePygmentsArgs(t *testing.T) {
 }
 
 func TestParseDefaultPygmentsArgs(t *testing.T) {
+	assert := require.New(t)
+
 	expect := "encoding=utf8,noclasses=false,style=foo"
 
 	for i, this := range []struct {
@@ -83,7 +94,10 @@ func TestParseDefaultPygmentsArgs(t *testing.T) {
 			v.Set("pygmentsUseClasses", b)
 		}
 
-		result, err := parsePygmentsOpts(v, this.in)
+		spec, err := NewContentSpec(v)
+		assert.NoError(err)
+
+		result, err := spec.createPygmentsOptionsString(this.in)
 		if err != nil {
 			t.Errorf("[%d] parsePygmentArgs failed: %s", i, err)
 			continue
@@ -93,3 +107,186 @@ func TestParseDefaultPygmentsArgs(t *testing.T) {
 		}
 	}
 }
+
+type chromaInfo struct {
+	classes            bool
+	lineNumbers        bool
+	highlightRangesLen int
+	highlightRangesStr string
+	baseLineNumber     int
+}
+
+func formatterChromaInfo(f *html.Formatter) chromaInfo {
+	v := reflect.ValueOf(f).Elem()
+	c := chromaInfo{}
+	// Hack:
+	c.classes = v.FieldByName("classes").Bool()
+	c.lineNumbers = v.FieldByName("lineNumbers").Bool()
+	c.baseLineNumber = int(v.FieldByName("baseLineNumber").Int())
+	vv := v.FieldByName("highlightRanges")
+	c.highlightRangesLen = vv.Len()
+	c.highlightRangesStr = fmt.Sprint(vv)
+
+	return c
+}
+
+func TestChromaHTMLHighlight(t *testing.T) {
+	assert := require.New(t)
+
+	v := viper.New()
+	v.Set("pygmentsUseClasses", true)
+	spec, err := NewContentSpec(v)
+	assert.NoError(err)
+
+	result, err := spec.Highlight(`echo "Hello"`, "bash", "")
+	assert.NoError(err)
+
+	assert.Contains(result, `<code class="language-bash" data-lang="bash"><span class="s7d2">echo</span> <span class="sc1c">&#34;Hello&#34;</span></code>`)
+
+}
+
+func TestChromaHTMLFormatterFromOptions(t *testing.T) {
+	assert := require.New(t)
+
+	for i, this := range []struct {
+		in                 string
+		pygmentsStyle      interface{}
+		pygmentsUseClasses interface{}
+		pygmentsOptions    string
+		assert             func(c chromaInfo)
+	}{
+		{"", "monokai", true, "style=manni,noclasses=true", func(c chromaInfo) {
+			assert.True(c.classes)
+			assert.False(c.lineNumbers)
+			assert.Equal(0, c.highlightRangesLen)
+
+		}},
+		{"", nil, nil, "style=monokai,noclasses=false", func(c chromaInfo) {
+			assert.True(c.classes)
+		}},
+		{"linenos=sure,hl_lines=1 2 3", nil, nil, "style=monokai,noclasses=false", func(c chromaInfo) {
+			assert.True(c.classes)
+			assert.True(c.lineNumbers)
+			assert.Equal(3, c.highlightRangesLen)
+			assert.Equal("[[1 1] [2 2] [3 3]]", c.highlightRangesStr)
+			assert.Equal(1, c.baseLineNumber)
+		}},
+		{"linenos=sure,hl_lines=1,linenostart=4", nil, nil, "style=monokai,noclasses=false", func(c chromaInfo) {
+			assert.True(c.classes)
+			assert.True(c.lineNumbers)
+			assert.Equal(1, c.highlightRangesLen)
+			// This compansates for https://github.com/alecthomas/chroma/issues/30
+			assert.Equal("[[4 4]]", c.highlightRangesStr)
+			assert.Equal(4, c.baseLineNumber)
+		}},
+		{"style=monokai,noclasses=false", nil, nil, "style=manni,noclasses=true", func(c chromaInfo) {
+			assert.True(c.classes)
+		}},
+		{"style=monokai,noclasses=true", "friendly", false, "style=manni,noclasses=false", func(c chromaInfo) {
+			assert.False(c.classes)
+		}},
+	} {
+		v := viper.New()
+
+		v.Set("pygmentsOptions", this.pygmentsOptions)
+
+		if s, ok := this.pygmentsStyle.(string); ok {
+			v.Set("pygmentsStyle", s)
+		}
+
+		if b, ok := this.pygmentsUseClasses.(bool); ok {
+			v.Set("pygmentsUseClasses", b)
+		}
+
+		spec, err := NewContentSpec(v)
+		assert.NoError(err)
+
+		opts, err := spec.parsePygmentsOpts(this.in)
+		if err != nil {
+			t.Fatalf("[%d] parsePygmentsOpts failed: %s", i, err)
+		}
+
+		chromaFormatter, err := spec.chromaFormatterFromOptions(opts)
+		if err != nil {
+			t.Fatalf("[%d] chromaFormatterFromOptions failed: %s", i, err)
+		}
+
+		this.assert(formatterChromaInfo(chromaFormatter.(*html.Formatter)))
+	}
+}
+
+func TestHlLinesToRanges(t *testing.T) {
+	var zero [][2]int
+
+	for _, this := range []struct {
+		in        string
+		startLine int
+		expected  interface{}
+	}{
+		{"", 1, zero},
+		{"1 4", 1, [][2]int{[2]int{1, 1}, [2]int{4, 4}}},
+		{"1 4", 2, [][2]int{[2]int{2, 2}, [2]int{5, 5}}},
+		{"1-4 5-8", 1, [][2]int{[2]int{1, 4}, [2]int{5, 8}}},
+		{" 1   4 ", 1, [][2]int{[2]int{1, 1}, [2]int{4, 4}}},
+		{"1-4    5-8 ", 1, [][2]int{[2]int{1, 4}, [2]int{5, 8}}},
+		{"1-4 5", 1, [][2]int{[2]int{1, 4}, [2]int{5, 5}}},
+		{"4 5-9", 1, [][2]int{[2]int{4, 4}, [2]int{5, 9}}},
+		{" 1 -4 5 - 8  ", 1, true},
+		{"a b", 1, true},
+	} {
+		got, err := hlLinesToRanges(this.startLine, this.in)
+
+		if expectErr, ok := this.expected.(bool); ok && expectErr {
+			if err == nil {
+				t.Fatal("No error")
+			}
+		} else if err != nil {
+			t.Fatalf("Got error: %s", err)
+		} else if !reflect.DeepEqual(this.expected, got) {
+			t.Fatalf("Expected\n%v but got\n%v", this.expected, got)
+		}
+	}
+}
+
+func BenchmarkChromaHighlight(b *testing.B) {
+	assert := require.New(b)
+	v := viper.New()
+
+	v.Set("pygmentsstyle", "trac")
+	v.Set("pygmentsuseclasses", false)
+	v.Set("pygmentsuseclassic", false)
+
+	code := `// GetTitleFunc returns a func that can be used to transform a string to
+// title case.
+//
+// The supported styles are
+//
+// - "Go" (strings.Title)
+// - "AP" (see https://www.apstylebook.com/)
+// - "Chicago" (see http://www.chicagomanualofstyle.org/home.html)
+//
+// If an unknown or empty style is provided, AP style is what you get.
+func GetTitleFunc(style string) func(s string) string {
+  switch strings.ToLower(style) {
+  case "go":
+    return strings.Title
+  case "chicago":
+    tc := transform.NewTitleConverter(transform.ChicagoStyle)
+    return tc.Title
+  default:
+    tc := transform.NewTitleConverter(transform.APStyle)
+    return tc.Title
+  }
+}
+`
+
+	spec, err := NewContentSpec(v)
+	assert.NoError(err)
+
+	for i := 0; i < b.N; i++ {
+		_, err := spec.Highlight(code, "go", "linenos=inline,hl_lines=8 15-17")
+		if err != nil {
+			b.Fatal(err)
+		}
+	}
+}