Add Image Diff for SVG files (#14867)

* Added type sniffer.

* Switched content detection from base to typesniffer.

* Added GuessContentType to Blob.

* Moved image info logic to client.
Added support for SVG images in diff.

* Restore old blocked svg behaviour.

* Added missing image formats.

* Execute image diff only when container is visible.

* add margin to spinner

* improve BIN tag on image diffs

* Default to render view.

* Show image diff on incomplete diff.

Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: Lauris BH <lauris@nix.lv>

7 files changed, 78 insertions, 57 deletions

diff --git a/routers/repo/compare.go b/routers/repo/compare.go
index d02ea0b160..f53a31769d 100644
--- a/routers/repo/compare.go
+++ b/routers/repo/compare.go
@@ -37,8 +37,20 @@ func setCompareContext(ctx *context.Context, base *git.Commit, head *git.Commit,
 	ctx.Data["BaseCommit"] = base
 	ctx.Data["HeadCommit"] = head
 
+	ctx.Data["GetBlobByPathForCommit"] = func(commit *git.Commit, path string) *git.Blob {
+		if commit == nil {
+			return nil
+		}
+
+		blob, err := commit.GetBlobByPath(path)
+		if err != nil {
+			return nil
+		}
+		return blob
+	}
+
 	setPathsCompareContext(ctx, base, head, headTarget)
-	setImageCompareContext(ctx, base, head)
+	setImageCompareContext(ctx)
 	setCsvCompareContext(ctx)
 }
 
@@ -57,27 +69,18 @@ func setPathsCompareContext(ctx *context.Context, base *git.Commit, head *git.Co
 }
 
 // setImageCompareContext sets context data that is required by image compare template
-func setImageCompareContext(ctx *context.Context, base *git.Commit, head *git.Commit) {
-	ctx.Data["IsImageFileInHead"] = head.IsImageFile
-	ctx.Data["IsImageFileInBase"] = base.IsImageFile
-	ctx.Data["ImageInfoBase"] = func(name string) *git.ImageMetaData {
-		if base == nil {
-			return nil
-		}
-		result, err := base.ImageInfo(name)
-		if err != nil {
-			log.Error("ImageInfo failed: %v", err)
-			return nil
+func setImageCompareContext(ctx *context.Context) {
+	ctx.Data["IsBlobAnImage"] = func(blob *git.Blob) bool {
+		if blob == nil {
+			return false
 		}
-		return result
-	}
-	ctx.Data["ImageInfo"] = func(name string) *git.ImageMetaData {
-		result, err := head.ImageInfo(name)
+
+		st, err := blob.GuessContentType()
 		if err != nil {
-			log.Error("ImageInfo failed: %v", err)
-			return nil
+			log.Error("GuessContentType failed: %v", err)
+			return false
 		}
-		return result
+		return st.IsImage() && (setting.UI.SVG.Enabled || !st.IsSvgImage())
 	}
 }
 
diff --git a/routers/repo/download.go b/routers/repo/download.go
index 4917c233ae..bbf4684b2e 100644
--- a/routers/repo/download.go
+++ b/routers/repo/download.go
@@ -12,7 +12,6 @@ import (
 	"path/filepath"
 	"strings"
 
-	"code.gitea.io/gitea/modules/base"
 	"code.gitea.io/gitea/modules/charset"
 	"code.gitea.io/gitea/modules/context"
 	"code.gitea.io/gitea/modules/git"
@@ -20,6 +19,7 @@ import (
 	"code.gitea.io/gitea/modules/lfs"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/typesniffer"
 )
 
 // ServeData download file from io.Reader
@@ -45,28 +45,32 @@ func ServeData(ctx *context.Context, name string, size int64, reader io.Reader)
 	// Google Chrome dislike commas in filenames, so let's change it to a space
 	name = strings.ReplaceAll(name, ",", " ")
 
-	if base.IsTextFile(buf) || ctx.QueryBool("render") {
+	st := typesniffer.DetectContentType(buf)
+
+	if st.IsText() || ctx.QueryBool("render") {
 		cs, err := charset.DetectEncoding(buf)
 		if err != nil {
 			log.Error("Detect raw file %s charset failed: %v, using by default utf-8", name, err)
 			cs = "utf-8"
 		}
 		ctx.Resp.Header().Set("Content-Type", "text/plain; charset="+strings.ToLower(cs))
-	} else if base.IsImageFile(buf) || base.IsPDFFile(buf) {
-		ctx.Resp.Header().Set("Content-Disposition", fmt.Sprintf(`inline; filename="%s"`, name))
-		ctx.Resp.Header().Set("Access-Control-Expose-Headers", "Content-Disposition")
-		if base.IsSVGImageFile(buf) {
-			ctx.Resp.Header().Set("Content-Security-Policy", "default-src 'none'; style-src 'unsafe-inline'; sandbox")
-			ctx.Resp.Header().Set("X-Content-Type-Options", "nosniff")
-			ctx.Resp.Header().Set("Content-Type", base.SVGMimeType)
-		}
 	} else {
-		ctx.Resp.Header().Set("Content-Disposition", fmt.Sprintf(`attachment; filename="%s"`, name))
 		ctx.Resp.Header().Set("Access-Control-Expose-Headers", "Content-Disposition")
-		if setting.MimeTypeMap.Enabled {
-			fileExtension := strings.ToLower(filepath.Ext(name))
-			if mimetype, ok := setting.MimeTypeMap.Map[fileExtension]; ok {
-				ctx.Resp.Header().Set("Content-Type", mimetype)
+
+		if (st.IsImage() || st.IsPDF()) && (setting.UI.SVG.Enabled || !st.IsSvgImage()) {
+			ctx.Resp.Header().Set("Content-Disposition", fmt.Sprintf(`inline; filename="%s"`, name))
+			if st.IsSvgImage() {
+				ctx.Resp.Header().Set("Content-Security-Policy", "default-src 'none'; style-src 'unsafe-inline'; sandbox")
+				ctx.Resp.Header().Set("X-Content-Type-Options", "nosniff")
+				ctx.Resp.Header().Set("Content-Type", typesniffer.SvgMimeType)
+			}
+		} else {
+			ctx.Resp.Header().Set("Content-Disposition", fmt.Sprintf(`attachment; filename="%s"`, name))
+			if setting.MimeTypeMap.Enabled {
+				fileExtension := strings.ToLower(filepath.Ext(name))
+				if mimetype, ok := setting.MimeTypeMap.Map[fileExtension]; ok {
+					ctx.Resp.Header().Set("Content-Type", mimetype)
+				}
 			}
 		}
 	}
diff --git a/routers/repo/editor.go b/routers/repo/editor.go
index 2a2c56952d..0f978c7b01 100644
--- a/routers/repo/editor.go
+++ b/routers/repo/editor.go
@@ -20,6 +20,7 @@ import (
 	"code.gitea.io/gitea/modules/repofiles"
 	repo_module "code.gitea.io/gitea/modules/repository"
 	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/typesniffer"
 	"code.gitea.io/gitea/modules/upload"
 	"code.gitea.io/gitea/modules/util"
 	"code.gitea.io/gitea/modules/web"
@@ -117,8 +118,8 @@ func editFile(ctx *context.Context, isNewFile bool) {
 		buf = buf[:n]
 
 		// Only some file types are editable online as text.
-		if !base.IsRepresentableAsText(buf) {
-			ctx.NotFound("base.IsRepresentableAsText", nil)
+		if !typesniffer.DetectContentType(buf).IsRepresentableAsText() {
+			ctx.NotFound("typesniffer.IsRepresentableAsText", nil)
 			return
 		}
 
diff --git a/routers/repo/lfs.go b/routers/repo/lfs.go
index c17bd2f87a..173ffb773f 100644
--- a/routers/repo/lfs.go
+++ b/routers/repo/lfs.go
@@ -25,6 +25,7 @@ import (
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/storage"
+	"code.gitea.io/gitea/modules/typesniffer"
 )
 
 const (
@@ -278,16 +279,16 @@ func LFSFileGet(ctx *context.Context) {
 	}
 	buf = buf[:n]
 
-	ctx.Data["IsTextFile"] = base.IsTextFile(buf)
-	isRepresentableAsText := base.IsRepresentableAsText(buf)
+	st := typesniffer.DetectContentType(buf)
+	ctx.Data["IsTextFile"] = st.IsText()
+	isRepresentableAsText := st.IsRepresentableAsText()
 
 	fileSize := meta.Size
 	ctx.Data["FileSize"] = meta.Size
 	ctx.Data["RawFileLink"] = fmt.Sprintf("%s%s.git/info/lfs/objects/%s/%s", setting.AppURL, ctx.Repo.Repository.FullName(), meta.Oid, "direct")
 	switch {
 	case isRepresentableAsText:
-		// This will be true for SVGs.
-		if base.IsImageFile(buf) {
+		if st.IsSvgImage() {
 			ctx.Data["IsImageFile"] = true
 		}
 
@@ -322,13 +323,13 @@ func LFSFileGet(ctx *context.Context) {
 		}
 		ctx.Data["LineNums"] = gotemplate.HTML(output.String())
 
-	case base.IsPDFFile(buf):
+	case st.IsPDF():
 		ctx.Data["IsPDFFile"] = true
-	case base.IsVideoFile(buf):
+	case st.IsVideo():
 		ctx.Data["IsVideoFile"] = true
-	case base.IsAudioFile(buf):
+	case st.IsAudio():
 		ctx.Data["IsAudioFile"] = true
-	case base.IsImageFile(buf):
+	case st.IsImage() && (setting.UI.SVG.Enabled || !st.IsSvgImage()):
 		ctx.Data["IsImageFile"] = true
 	}
 	ctx.HTML(http.StatusOK, tplSettingsLFSFile)
diff --git a/routers/repo/setting.go b/routers/repo/setting.go
index 51a0e01164..21a82491fe 100644
--- a/routers/repo/setting.go
+++ b/routers/repo/setting.go
@@ -24,6 +24,7 @@ import (
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/structs"
 	"code.gitea.io/gitea/modules/timeutil"
+	"code.gitea.io/gitea/modules/typesniffer"
 	"code.gitea.io/gitea/modules/validation"
 	"code.gitea.io/gitea/modules/web"
 	"code.gitea.io/gitea/routers/utils"
@@ -1021,7 +1022,8 @@ func UpdateAvatarSetting(ctx *context.Context, form forms.AvatarForm) error {
 	if err != nil {
 		return fmt.Errorf("ioutil.ReadAll: %v", err)
 	}
-	if !base.IsImageFile(data) {
+	st := typesniffer.DetectContentType(data)
+	if !(st.IsImage() && !st.IsSvgImage()) {
 		return errors.New(ctx.Tr("settings.uploaded_avatar_not_a_image"))
 	}
 	if err = ctxRepo.UploadAvatar(data); err != nil {
diff --git a/routers/repo/view.go b/routers/repo/view.go
index 285cacc2df..30d7de4078 100644
--- a/routers/repo/view.go
+++ b/routers/repo/view.go
@@ -29,6 +29,7 @@ import (
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/markup"
 	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/typesniffer"
 )
 
 const (
@@ -265,7 +266,9 @@ func renderDirectory(ctx *context.Context, treeLink string) {
 		n, _ := dataRc.Read(buf)
 		buf = buf[:n]
 
-		isTextFile := base.IsTextFile(buf)
+		st := typesniffer.DetectContentType(buf)
+		isTextFile := st.IsText()
+
 		ctx.Data["FileIsText"] = isTextFile
 		ctx.Data["FileName"] = readmeFile.name
 		fileSize := int64(0)
@@ -302,7 +305,8 @@ func renderDirectory(ctx *context.Context, treeLink string) {
 					}
 					buf = buf[:n]
 
-					isTextFile = base.IsTextFile(buf)
+					st = typesniffer.DetectContentType(buf)
+					isTextFile = st.IsText()
 					ctx.Data["IsTextFile"] = isTextFile
 
 					fileSize = meta.Size
@@ -405,7 +409,9 @@ func renderFile(ctx *context.Context, entry *git.TreeEntry, treeLink, rawLink st
 	n, _ := dataRc.Read(buf)
 	buf = buf[:n]
 
-	isTextFile := base.IsTextFile(buf)
+	st := typesniffer.DetectContentType(buf)
+	isTextFile := st.IsText()
+
 	isLFSFile := false
 	isDisplayingSource := ctx.Query("display") == "source"
 	isDisplayingRendered := !isDisplayingSource
@@ -441,14 +447,16 @@ func renderFile(ctx *context.Context, entry *git.TreeEntry, treeLink, rawLink st
 				}
 				buf = buf[:n]
 
-				isTextFile = base.IsTextFile(buf)
+				st = typesniffer.DetectContentType(buf)
+				isTextFile = st.IsText()
+
 				fileSize = meta.Size
 				ctx.Data["RawFileLink"] = fmt.Sprintf("%s/media/%s/%s", ctx.Repo.RepoLink, ctx.Repo.BranchNameSubURL(), ctx.Repo.TreePath)
 			}
 		}
 	}
 
-	isRepresentableAsText := base.IsRepresentableAsText(buf)
+	isRepresentableAsText := st.IsRepresentableAsText()
 	if !isRepresentableAsText {
 		// If we can't show plain text, always try to render.
 		isDisplayingSource = false
@@ -483,8 +491,7 @@ func renderFile(ctx *context.Context, entry *git.TreeEntry, treeLink, rawLink st
 
 	switch {
 	case isRepresentableAsText:
-		// This will be true for SVGs.
-		if base.IsImageFile(buf) {
+		if st.IsSvgImage() {
 			ctx.Data["IsImageFile"] = true
 			ctx.Data["HasSourceRenderedToggle"] = true
 		}
@@ -540,13 +547,13 @@ func renderFile(ctx *context.Context, entry *git.TreeEntry, treeLink, rawLink st
 			}
 		}
 
-	case base.IsPDFFile(buf):
+	case st.IsPDF():
 		ctx.Data["IsPDFFile"] = true
-	case base.IsVideoFile(buf):
+	case st.IsVideo():
 		ctx.Data["IsVideoFile"] = true
-	case base.IsAudioFile(buf):
+	case st.IsAudio():
 		ctx.Data["IsAudioFile"] = true
-	case base.IsImageFile(buf):
+	case st.IsImage() && (setting.UI.SVG.Enabled || !st.IsSvgImage()):
 		ctx.Data["IsImageFile"] = true
 	default:
 		if fileSize >= setting.UI.MaxDisplayFileSize {
diff --git a/routers/user/setting/profile.go b/routers/user/setting/profile.go
index 8cde81f295..20042caca4 100644
--- a/routers/user/setting/profile.go
+++ b/routers/user/setting/profile.go
@@ -19,6 +19,7 @@ import (
 	"code.gitea.io/gitea/modules/context"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/typesniffer"
 	"code.gitea.io/gitea/modules/util"
 	"code.gitea.io/gitea/modules/web"
 	"code.gitea.io/gitea/modules/web/middleware"
@@ -159,7 +160,9 @@ func UpdateAvatarSetting(ctx *context.Context, form *forms.AvatarForm, ctxUser *
 		if err != nil {
 			return fmt.Errorf("ioutil.ReadAll: %v", err)
 		}
-		if !base.IsImageFile(data) {
+
+		st := typesniffer.DetectContentType(data)
+		if !(st.IsImage() && !st.IsSvgImage()) {
 			return errors.New(ctx.Tr("settings.uploaded_avatar_not_a_image"))
 		}
 		if err = ctxUser.UploadAvatar(data); err != nil {