Add support for 3D/CAD file formats preview (#34794)

Fix #34775 

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

Author: kerwin612

modules/git/blob.go

@@ -22,17 +22,22 @@ func (b *Blob) Name() string {
 	return b.name
 }
 
-// GetBlobContent Gets the limited content of the blob as raw text
-func (b *Blob) GetBlobContent(limit int64) (string, error) {
+// GetBlobBytes Gets the limited content of the blob
+func (b *Blob) GetBlobBytes(limit int64) ([]byte, error) {
 	if limit <= 0 {
-		return "", nil
+		return nil, nil
 	}
 	dataRc, err := b.DataAsync()
 	if err != nil {
-		return "", err
+		return nil, err
 	}
 	defer dataRc.Close()
-	buf, err := util.ReadWithLimit(dataRc, int(limit))
+	return util.ReadWithLimit(dataRc, int(limit))
+}
+
+// GetBlobContent Gets the limited content of the blob as raw text
+func (b *Blob) GetBlobContent(limit int64) (string, error) {
+	buf, err := b.GetBlobBytes(limit)
 	return string(buf), err
 }
 
@@ -99,11 +104,9 @@ loop:
 
 // GuessContentType guesses the content type of the blob.
 func (b *Blob) GuessContentType() (typesniffer.SniffedType, error) {
-	r, err := b.DataAsync()
+	buf, err := b.GetBlobBytes(typesniffer.SniffContentSize)
 	if err != nil {
 		return typesniffer.SniffedType{}, err
 	}
-	defer r.Close()
-
-	return typesniffer.DetectContentTypeFromReader(r)
+	return typesniffer.DetectContentType(buf), nil
 }

modules/markup/console/console.go

@@ -6,13 +6,14 @@ package console
 import (
 	"bytes"
 	"io"
-	"path"
+	"unicode/utf8"
 
 	"code.gitea.io/gitea/modules/markup"
 	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/typesniffer"
+	"code.gitea.io/gitea/modules/util"
 
 	trend "github.com/buildkite/terminal-to-html/v3"
-	"github.com/go-enry/go-enry/v2"
 )
 
 func init() {
@@ -22,6 +23,8 @@ func init() {
 // Renderer implements markup.Renderer
 type Renderer struct{}
 
+var _ markup.RendererContentDetector = (*Renderer)(nil)
+
 // Name implements markup.Renderer
 func (Renderer) Name() string {
 	return "console"
@@ -40,15 +43,36 @@ func (Renderer) SanitizerRules() []setting.MarkupSanitizerRule {
 }
 
 // CanRender implements markup.RendererContentDetector
-func (Renderer) CanRender(filename string, input io.Reader) bool {
-	buf, err := io.ReadAll(input)
-	if err != nil {
+func (Renderer) CanRender(filename string, sniffedType typesniffer.SniffedType, prefetchBuf []byte) bool {
+	if !sniffedType.IsTextPlain() {
 		return false
 	}
-	if enry.GetLanguage(path.Base(filename), buf) != enry.OtherLanguage {
+
+	s := util.UnsafeBytesToString(prefetchBuf)
+	rs := []rune(s)
+	cnt := 0
+	firstErrPos := -1
+	isCtrlSep := func(p int) bool {
+		return p < len(rs) && (rs[p] == ';' || rs[p] == 'm')
+	}
+	for i, c := range rs {
+		if c == 0 {
+			return false
+		}
+		if c == '\x1b' {
+			match := i+1 < len(rs) && rs[i+1] == '['
+			if match && (isCtrlSep(i+2) || isCtrlSep(i+3) || isCtrlSep(i+4) || isCtrlSep(i+5)) {
+				cnt++
+			}
+		}
+		if c == utf8.RuneError && firstErrPos == -1 {
+			firstErrPos = i
+		}
+	}
+	if firstErrPos != -1 && firstErrPos != len(rs)-1 {
 		return false
 	}
-	return bytes.ContainsRune(buf, '\x1b')
+	return cnt >= 2 // only render it as console output if there are at least two escape sequences
 }
 
 // Render renders terminal colors to HTML with all specific handling stuff.

modules/markup/console/console_test.go

@@ -8,23 +8,39 @@ import (
 	"testing"
 
 	"code.gitea.io/gitea/modules/markup"
+	"code.gitea.io/gitea/modules/typesniffer"
 
 	"github.com/stretchr/testify/assert"
 )
 
 func TestRenderConsole(t *testing.T) {
-	var render Renderer
-	kases := map[string]string{
-		"\x1b[37m\x1b[40mnpm\x1b[0m \x1b[0m\x1b[32minfo\x1b[0m \x1b[0m\x1b[35mit worked if it ends with\x1b[0m ok": "<span class=\"term-fg37 term-bg40\">npm</span> <span class=\"term-fg32\">info</span> <span class=\"term-fg35\">it worked if it ends with</span> ok",
+	cases := []struct {
+		input    string
+		expected string
+	}{
+		{"\x1b[37m\x1b[40mnpm\x1b[0m \x1b[0m\x1b[32minfo\x1b[0m \x1b[0m\x1b[35mit worked if it ends with\x1b[0m ok", `<span class="term-fg37 term-bg40">npm</span> <span class="term-fg32">info</span> <span class="term-fg35">it worked if it ends with</span> ok`},
+		{"\x1b[1;2m \x1b[123m 啊", `<span class="term-fg2">  啊</span>`},
+		{"\x1b[1;2m \x1b[123m \xef", `<span class="term-fg2">  �</span>`},
+		{"\x1b[1;2m \x1b[123m \xef \xef", ``},
+		{"\x1b[12", ``},
+		{"\x1b[1", ``},
+		{"\x1b[FOO\x1b[", ``},
+		{"\x1b[mFOO\x1b[m", `FOO`},
 	}
 
-	for k, v := range kases {
+	var render Renderer
+	for i, c := range cases {
 		var buf strings.Builder
-		canRender := render.CanRender("test", strings.NewReader(k))
-		assert.True(t, canRender)
+		st := typesniffer.DetectContentType([]byte(c.input))
+		canRender := render.CanRender("test", st, []byte(c.input))
+		if c.expected == "" {
+			assert.False(t, canRender, "case %d: expected not to render", i)
+			continue
+		}
 
-		err := render.Render(markup.NewRenderContext(t.Context()), strings.NewReader(k), &buf)
+		assert.True(t, canRender)
+		err := render.Render(markup.NewRenderContext(t.Context()), strings.NewReader(c.input), &buf)
 		assert.NoError(t, err)
-		assert.Equal(t, v, buf.String())
+		assert.Equal(t, c.expected, buf.String())
 	}
 }

modules/markup/renderer.go

@@ -4,12 +4,12 @@
 package markup
 
 import (
-	"bytes"
 	"io"
 	"path"
 	"strings"
 
 	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/typesniffer"
 )
 
 // Renderer defines an interface for rendering markup file to HTML
@@ -37,7 +37,7 @@ type ExternalRenderer interface {
 // RendererContentDetector detects if the content can be rendered
 // by specified renderer
 type RendererContentDetector interface {
-	CanRender(filename string, input io.Reader) bool
+	CanRender(filename string, sniffedType typesniffer.SniffedType, prefetchBuf []byte) bool
 }
 
 var (
@@ -60,13 +60,9 @@ func GetRendererByFileName(filename string) Renderer {
 }
 
 // DetectRendererType detects the markup type of the content
-func DetectRendererType(filename string, input io.Reader) string {
-	buf, err := io.ReadAll(input)
-	if err != nil {
-		return ""
-	}
+func DetectRendererType(filename string, sniffedType typesniffer.SniffedType, prefetchBuf []byte) string {
 	for _, renderer := range renderers {
-		if detector, ok := renderer.(RendererContentDetector); ok && detector.CanRender(filename, bytes.NewReader(buf)) {
+		if detector, ok := renderer.(RendererContentDetector); ok && detector.CanRender(filename, sniffedType, prefetchBuf) {
 			return renderer.Name()
 		}
 	}

modules/typesniffer/typesniffer.go

@@ -6,18 +6,14 @@ package typesniffer
 import (
 	"bytes"
 	"encoding/binary"
-	"fmt"
-	"io"
 	"net/http"
 	"regexp"
 	"slices"
 	"strings"
-
-	"code.gitea.io/gitea/modules/util"
+	"sync"
 )
 
-// Use at most this many bytes to determine Content Type.
-const sniffLen = 1024
+const SniffContentSize = 1024
 
 const (
 	MimeTypeImageSvg  = "image/svg+xml"
@@ -26,22 +22,30 @@ const (
 	MimeTypeApplicationOctetStream = "application/octet-stream"
 )
 
-var (
-	svgComment       = regexp.MustCompile(`(?s)<!--.*?-->`)
-	svgTagRegex      = regexp.MustCompile(`(?si)\A\s*(?:(<!DOCTYPE\s+svg([\s:]+.*?>|>))\s*)*<svg\b`)
-	svgTagInXMLRegex = regexp.MustCompile(`(?si)\A<\?xml\b.*?\?>\s*(?:(<!DOCTYPE\s+svg([\s:]+.*?>|>))\s*)*<svg\b`)
-)
-
-// SniffedType contains information about a blobs type.
+var globalVars = sync.OnceValue(func() (ret struct {
+	svgComment, svgTagRegex, svgTagInXMLRegex *regexp.Regexp
+},
+) {
+	ret.svgComment = regexp.MustCompile(`(?s)<!--.*?-->`)
+	ret.svgTagRegex = regexp.MustCompile(`(?si)\A\s*(?:(<!DOCTYPE\s+svg([\s:]+.*?>|>))\s*)*<svg\b`)
+	ret.svgTagInXMLRegex = regexp.MustCompile(`(?si)\A<\?xml\b.*?\?>\s*(?:(<!DOCTYPE\s+svg([\s:]+.*?>|>))\s*)*<svg\b`)
+	return ret
+})
+
+// SniffedType contains information about a blob's type.
 type SniffedType struct {
 	contentType string
 }
 
-// IsText etects if content format is plain text.
+// IsText detects if the content format is text family, including text/plain, text/html, text/css, etc.
 func (ct SniffedType) IsText() bool {
 	return strings.Contains(ct.contentType, "text/")
 }
 
+func (ct SniffedType) IsTextPlain() bool {
+	return strings.Contains(ct.contentType, "text/plain")
+}
+
 // IsImage detects if data is an image format
 func (ct SniffedType) IsImage() bool {
 	return strings.Contains(ct.contentType, "image/")
@@ -57,12 +61,12 @@ func (ct SniffedType) IsPDF() bool {
 	return strings.Contains(ct.contentType, "application/pdf")
 }
 
-// IsVideo detects if data is an video format
+// IsVideo detects if data is a video format
 func (ct SniffedType) IsVideo() bool {
 	return strings.Contains(ct.contentType, "video/")
 }
 
-// IsAudio detects if data is an video format
+// IsAudio detects if data is a video format
 func (ct SniffedType) IsAudio() bool {
 	return strings.Contains(ct.contentType, "audio/")
 }
@@ -103,33 +107,34 @@ func detectFileTypeBox(data []byte) (brands []string, found bool) {
 	return brands, true
 }
 
-// DetectContentType extends http.DetectContentType with more content types. Defaults to text/unknown if input is empty.
+// DetectContentType extends http.DetectContentType with more content types. Defaults to text/plain if input is empty.
 func DetectContentType(data []byte) SniffedType {
 	if len(data) == 0 {
-		return SniffedType{"text/unknown"}
+		return SniffedType{"text/plain"}
 	}
 
 	ct := http.DetectContentType(data)
 
-	if len(data) > sniffLen {
-		data = data[:sniffLen]
+	if len(data) > SniffContentSize {
+		data = data[:SniffContentSize]
 	}
 
+	vars := globalVars()
 	// SVG is unsupported by http.DetectContentType, https://github.com/golang/go/issues/15888
 	detectByHTML := strings.Contains(ct, "text/plain") || strings.Contains(ct, "text/html")
 	detectByXML := strings.Contains(ct, "text/xml")
 	if detectByHTML || detectByXML {
-		dataProcessed := svgComment.ReplaceAll(data, nil)
+		dataProcessed := vars.svgComment.ReplaceAll(data, nil)
 		dataProcessed = bytes.TrimSpace(dataProcessed)
-		if detectByHTML && svgTagRegex.Match(dataProcessed) ||
-			detectByXML && svgTagInXMLRegex.Match(dataProcessed) {
+		if detectByHTML && vars.svgTagRegex.Match(dataProcessed) ||
+			detectByXML && vars.svgTagInXMLRegex.Match(dataProcessed) {
 			ct = MimeTypeImageSvg
 		}
 	}
 
 	if strings.HasPrefix(ct, "audio/") && bytes.HasPrefix(data, []byte("ID3")) {
 		// The MP3 detection is quite inaccurate, any content with "ID3" prefix will result in "audio/mpeg".
-		// So remove the "ID3" prefix and detect again, if result is text, then it must be text content.
+		// So remove the "ID3" prefix and detect again, then if the result is "text", it must be text content.
 		// This works especially because audio files contain many unprintable/invalid characters like `0x00`
 		ct2 := http.DetectContentType(data[3:])
 		if strings.HasPrefix(ct2, "text/") {
@@ -155,15 +160,3 @@ func DetectContentType(data []byte) SniffedType {
 	}
 	return SniffedType{ct}
 }
-
-// DetectContentTypeFromReader guesses the content type contained in the reader.
-func DetectContentTypeFromReader(r io.Reader) (SniffedType, error) {
-	buf := make([]byte, sniffLen)
-	n, err := util.ReadAtMost(r, buf)
-	if err != nil {
-		return SniffedType{}, fmt.Errorf("DetectContentTypeFromReader io error: %w", err)
-	}
-	buf = buf[:n]
-
-	return DetectContentType(buf), nil
-}

modules/typesniffer/typesniffer_test.go

@@ -4,7 +4,6 @@
 package typesniffer
 
 import (
-	"bytes"
 	"encoding/base64"
 	"encoding/hex"
 	"strings"
@@ -17,7 +16,7 @@ func TestDetectContentTypeLongerThanSniffLen(t *testing.T) {
 	// Pre-condition: Shorter than sniffLen detects SVG.
 	assert.Equal(t, "image/svg+xml", DetectContentType([]byte(`<!-- Comment --><svg></svg>`)).contentType)
 	// Longer than sniffLen detects something else.
-	assert.NotEqual(t, "image/svg+xml", DetectContentType([]byte(`<!-- `+strings.Repeat("x", sniffLen)+` --><svg></svg>`)).contentType)
+	assert.NotEqual(t, "image/svg+xml", DetectContentType([]byte(`<!-- `+strings.Repeat("x", SniffContentSize)+` --><svg></svg>`)).contentType)
 }
 
 func TestIsTextFile(t *testing.T) {
@@ -116,22 +115,13 @@ func TestIsAudio(t *testing.T) {
 	assert.True(t, DetectContentType([]byte("ID3Toy\n====\t* hi 🌞, ..."+"🌛"[0:2])).IsText()) // test ID3 tag with incomplete UTF8 char
 }
 
-func TestDetectContentTypeFromReader(t *testing.T) {
-	mp3, _ := base64.StdEncoding.DecodeString("SUQzBAAAAAABAFRYWFgAAAASAAADbWFqb3JfYnJhbmQAbXA0MgBUWFhYAAAAEQAAA21pbm9yX3Zl")
-	st, err := DetectContentTypeFromReader(bytes.NewReader(mp3))
-	assert.NoError(t, err)
-	assert.True(t, st.IsAudio())
-}
-
 func TestDetectContentTypeOgg(t *testing.T) {
 	oggAudio, _ := hex.DecodeString("4f67675300020000000000000000352f0000000000007dc39163011e01766f72626973000000000244ac0000000000000071020000000000b8014f6767530000")
-	st, err := DetectContentTypeFromReader(bytes.NewReader(oggAudio))
-	assert.NoError(t, err)
+	st := DetectContentType(oggAudio)
 	assert.True(t, st.IsAudio())
 
 	oggVideo, _ := hex.DecodeString("4f676753000200000000000000007d9747ef000000009b59daf3012a807468656f7261030201001e00110001e000010e00020000001e00000001000001000001")
-	st, err = DetectContentTypeFromReader(bytes.NewReader(oggVideo))
-	assert.NoError(t, err)
+	st = DetectContentType(oggVideo)
 	assert.True(t, st.IsVideo())
 }