Render embedded code preview by permlink in markdown

modules/indexer/code/search.go

@@ -70,9 +70,9 @@ func writeStrings(buf *bytes.Buffer, strs ...string) error {
 	return nil
 }
 
-func HighlightSearchResultCode(filename string, lineNums []int, code string) []ResultLine {
+func HighlightSearchResultCode(filename, language string, lineNums []int, code string) []ResultLine {
 	// we should highlight the whole code block first, otherwise it doesn't work well with multiple line highlighting
-	hl, _ := highlight.Code(filename, "", code)
+	hl, _ := highlight.Code(filename, language, code)
 	highlightedLines := strings.Split(string(hl), "\n")
 
 	// The lineNums outputted by highlight.Code might not match the original lineNums, because "highlight" removes the last `\n`
@@ -122,7 +122,7 @@ func searchResult(result *internal.SearchResult, startIndex, endIndex int) (*Res
 		UpdatedUnix: result.UpdatedUnix,
 		Language:    result.Language,
 		Color:       result.Color,
-		Lines:       HighlightSearchResultCode(result.Filename, lineNums, formattedLinesBuffer.String()),
+		Lines:       HighlightSearchResultCode(result.Filename, result.Language, lineNums, formattedLinesBuffer.String()),
 	}, nil
 }
 

modules/markup/html.go

@@ -171,6 +171,7 @@ type processor func(ctx *RenderContext, node *html.Node)
 var defaultProcessors = []processor{
 	fullIssuePatternProcessor,
 	comparePatternProcessor,
+	codePreviewPatternProcessor,
 	fullHashPatternProcessor,
 	shortLinkProcessor,
 	linkProcessor,

modules/markup/html_codepreview.go

@@ -0,0 +1,75 @@
+// Copyright 2024 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package markup
+
+import (
+	"html/template"
+	"net/url"
+	"regexp"
+	"strconv"
+	"strings"
+
+	"code.gitea.io/gitea/modules/httplib"
+
+	"golang.org/x/net/html"
+)
+
+// codePreviewPattern matches "http://domain/.../{owner}/{repo}/src/commit/{commit}/{filepath}#L10-L20"
+var codePreviewPattern = regexp.MustCompile(`https?://\S+/([^\s/]+)/([^\s/]+)/src/commit/([0-9a-f]{7,64})(/\S+)#(L\d+(-L\d+)?)`)
+
+type RenderCodePreviewOptions struct {
+	FullURL   string
+	OwnerName string
+	RepoName  string
+	CommitID  string
+	FilePath  string
+
+	LineStart, LineStop int
+}
+
+func renderCodeBlock(ctx *RenderContext, node *html.Node) (urlPosStart, urlPosStop int, htm template.HTML, err error) {
+	m := codePreviewPattern.FindStringSubmatchIndex(node.Data)
+	if m == nil {
+		return 0, 0, "", nil
+	}
+
+	opts := RenderCodePreviewOptions{
+		FullURL:   node.Data[m[0]:m[1]],
+		OwnerName: node.Data[m[2]:m[3]],
+		RepoName:  node.Data[m[4]:m[5]],
+		CommitID:  node.Data[m[6]:m[7]],
+		FilePath:  node.Data[m[8]:m[9]],
+	}
+	if !httplib.IsCurrentGiteaSiteURL(opts.FullURL) {
+		return 0, 0, "", nil
+	}
+	u, err := url.Parse(opts.FilePath)
+	if err != nil {
+		return 0, 0, "", err
+	}
+	opts.FilePath = strings.TrimPrefix(u.Path, "/")
+
+	lineStartStr, lineStopStr, _ := strings.Cut(node.Data[m[10]:m[11]], "-")
+	lineStart, _ := strconv.Atoi(strings.TrimPrefix(lineStartStr, "L"))
+	lineStop, _ := strconv.Atoi(strings.TrimPrefix(lineStopStr, "L"))
+	opts.LineStart, opts.LineStop = lineStart, lineStop
+	h, err := DefaultProcessorHelper.RenderRepoFileCodePreview(ctx.Ctx, opts)
+	return m[0], m[1], h, err
+}
+
+func codePreviewPatternProcessor(ctx *RenderContext, node *html.Node) {
+	for node != nil {
+		urlPosStart, urlPosEnd, h, err := renderCodeBlock(ctx, node)
+		if err != nil || h == "" {
+			node = node.NextSibling
+			continue
+		}
+		next := node.NextSibling
+		nodeText := node.Data
+		node.Data = nodeText[:urlPosStart]
+		node.Parent.InsertBefore(&html.Node{Type: html.RawNode, Data: string(h)}, next)
+		node.Parent.InsertBefore(&html.Node{Type: html.TextNode, Data: nodeText[urlPosEnd:]}, next)
+		node = next
+	}
+}

modules/markup/html_codepreview_test.go

@@ -0,0 +1,34 @@
+// Copyright 2024 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package markup_test
+
+import (
+	"context"
+	"html/template"
+	"strings"
+	"testing"
+
+	"code.gitea.io/gitea/modules/git"
+	"code.gitea.io/gitea/modules/markup"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestRenderCodePreview(t *testing.T) {
+	markup.Init(&markup.ProcessorHelper{
+		RenderRepoFileCodePreview: func(ctx context.Context, opts markup.RenderCodePreviewOptions) (template.HTML, error) {
+			return "<div>code preview</div>", nil
+		},
+	})
+	test := func(input, expected string) {
+		buffer, err := markup.RenderString(&markup.RenderContext{
+			Ctx:  git.DefaultContext,
+			Type: "markdown",
+		}, input)
+		assert.NoError(t, err)
+		assert.Equal(t, strings.TrimSpace(expected), strings.TrimSpace(buffer))
+	}
+	test("http://localhost:3000/owner/repo/src/commit/0123456789/foo/bar.md#L10-L20", "<p><div>code preview</div></p>")
+	test("http://other/owner/repo/src/commit/0123456789/foo/bar.md#L10-L20", `<p><a href="http://other/owner/repo/src/commit/0123456789/foo/bar.md#L10-L20" rel="nofollow">http://other/owner/repo/src/commit/0123456789/foo/bar.md#L10-L20</a></p>`)
+}

modules/markup/renderer.go

@@ -8,6 +8,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"html/template"
 	"io"
 	"net/url"
 	"path/filepath"
@@ -33,6 +34,8 @@ type ProcessorHelper struct {
 	IsUsernameMentionable func(ctx context.Context, username string) bool
 
 	ElementDir string // the direction of the elements, eg: "ltr", "rtl", "auto", default to no direction attribute
+
+	RenderRepoFileCodePreview func(ctx context.Context, options RenderCodePreviewOptions) (template.HTML, error)
 }
 
 var DefaultProcessorHelper ProcessorHelper

modules/markup/sanitizer.go

@@ -58,7 +58,13 @@ func createDefaultPolicy() *bluemonday.Policy {
 	policy := bluemonday.UGCPolicy()
 
 	// For JS code copy and Mermaid loading state
-	policy.AllowAttrs("class").Matching(regexp.MustCompile(`^code-block( is-loading)?$`)).OnElements("pre")
+	policy.AllowAttrs("class").Matching(regexp.MustCompile(`^code-block( is-loading)?$`)).Globally()
+
+	// For code preview
+	policy.AllowAttrs("class").Matching(regexp.MustCompile(`^code-preview-[-\w]+$`)).Globally()
+	policy.AllowAttrs("class").Matching(regexp.MustCompile(`^lines-num$`)).Globally()
+	policy.AllowAttrs("class").Matching(regexp.MustCompile(`^lines-code chroma$`)).Globally()
+	policy.AllowAttrs("data-line-number").OnElements("span")
 
 	// For color preview
 	policy.AllowAttrs("class").Matching(regexp.MustCompile(`^color-preview$`)).OnElements("span")

routers/web/repo/search.go

@@ -81,7 +81,7 @@ func Search(ctx *context.Context) {
 				// UpdatedUnix: not supported yet
 				// Language:    not supported yet
 				// Color:       not supported yet
-				Lines: code_indexer.HighlightSearchResultCode(r.Filename, r.LineNumbers, strings.Join(r.LineCodes, "\n")),
+				Lines: code_indexer.HighlightSearchResultCode(r.Filename, "", r.LineNumbers, strings.Join(r.LineCodes, "\n")),
 			})
 		}
 	}

services/contexttest/context_tests.go

@@ -63,6 +63,7 @@ func MockContext(t *testing.T, reqPath string, opts ...MockContextOption) (*cont
 	base.Locale = &translation.MockLocale{}
 
 	ctx := context.NewWebContext(base, opt.Render, nil)
+	ctx.AppendContextValue(context.WebContextKey, ctx)
 	ctx.PageData = map[string]any{}
 	ctx.Data["PageStartTime"] = time.Now()
 	chiCtx := chi.NewRouteContext()

services/markup/main_test.go

@@ -11,6 +11,6 @@ import (
 
 func TestMain(m *testing.M) {
 	unittest.MainTest(m, &unittest.TestOptions{
-		FixtureFiles: []string{"user.yml"},
+		FixtureFiles: []string{"user.yml", "repository.yml", "access.yml", "repo_unit.yml"},
 	})
 }

services/markup/processorhelper.go

@@ -14,6 +14,8 @@ import (
 func ProcessorHelper() *markup.ProcessorHelper {
 	return &markup.ProcessorHelper{
 		ElementDir: "auto", // set dir="auto" for necessary (eg: <p>, <h?>, etc) tags
+
+		RenderRepoFileCodePreview: renderRepoFileCodePreview,
 		IsUsernameMentionable: func(ctx context.Context, username string) bool {
 			mentionedUser, err := user.GetUserByName(ctx, username)
 			if err != nil {

services/markup/processorhelper_codepreview.go

@@ -0,0 +1,106 @@
+// Copyright 2024 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package markup
+
+import (
+	"bufio"
+	"context"
+	"fmt"
+	"html/template"
+	"strings"
+
+	"code.gitea.io/gitea/models/perm/access"
+	"code.gitea.io/gitea/models/repo"
+	"code.gitea.io/gitea/models/unit"
+	"code.gitea.io/gitea/modules/gitrepo"
+	"code.gitea.io/gitea/modules/indexer/code"
+	"code.gitea.io/gitea/modules/markup"
+	"code.gitea.io/gitea/modules/setting"
+	gitea_context "code.gitea.io/gitea/services/context"
+	"code.gitea.io/gitea/services/repository/files"
+)
+
+func renderRepoFileCodePreview(ctx context.Context, opts markup.RenderCodePreviewOptions) (template.HTML, error) {
+	opts.LineStop = max(opts.LineStop, 1)
+	lineCount := opts.LineStop - opts.LineStart + 1
+	if lineCount <= 0 || lineCount > 140 /* GitHub at most show 140 lines */ {
+		lineCount = 10
+		opts.LineStop = opts.LineStart + lineCount
+	}
+
+	dbRepo, err := repo.GetRepositoryByOwnerAndName(ctx, opts.OwnerName, opts.RepoName)
+	if err != nil {
+		return "", err
+	}
+
+	webCtx, ok := ctx.Value(gitea_context.WebContextKey).(*gitea_context.Context)
+	if !ok {
+		return "", fmt.Errorf("context is not a web context")
+	}
+	doer := webCtx.Doer
+
+	perms, err := access.GetUserRepoPermission(ctx, dbRepo, doer)
+	if err != nil {
+		return "", err
+	}
+	if !perms.CanRead(unit.TypeCode) {
+		return "", fmt.Errorf("no permission")
+	}
+
+	gitRepo, err := gitrepo.OpenRepository(ctx, dbRepo)
+	if err != nil {
+		return "", err
+	}
+	defer gitRepo.Close()
+
+	commit, err := gitRepo.GetCommit(opts.CommitID)
+	if err != nil {
+		return "", err
+	}
+
+	language, _ := files.TryGetContentLanguage(gitRepo, opts.CommitID, opts.FilePath)
+	blob, err := commit.GetBlobByPath(opts.FilePath)
+	if err != nil {
+		return "", err
+	}
+
+	if blob.Size() > setting.UI.MaxDisplayFileSize {
+		return "", fmt.Errorf("file is too large")
+	}
+
+	dataRc, err := blob.DataAsync()
+	if err != nil {
+		return "", err
+	}
+	defer dataRc.Close()
+
+	reader := bufio.NewReader(dataRc)
+
+	for i := 1; i < opts.LineStart; i++ {
+		if _, err = reader.ReadBytes('\n'); err != nil {
+			return "", err
+		}
+	}
+
+	lineNums := make([]int, 0, lineCount)
+	lineCodes := make([]string, 0, lineCount)
+	for i := opts.LineStart; i <= opts.LineStop; i++ {
+		if line, err := reader.ReadString('\n'); err != nil {
+			break
+		} else {
+			lineNums = append(lineNums, i)
+			lineCodes = append(lineCodes, line)
+		}
+	}
+	highlightLines := code.HighlightSearchResultCode(opts.FilePath, language, lineNums, strings.Join(lineCodes, ""))
+	return webCtx.RenderToHTML("base/markup_codepreview", map[string]any{
+		"FullURL":        opts.FullURL,
+		"FilePath":       opts.FilePath,
+		"LineStart":      opts.LineStart,
+		"LineStop":       opts.LineStop,
+		"RepoLink":       dbRepo.Link(),
+		"CommitID":       opts.CommitID,
+		"HighlightLines": highlightLines,
+	})
+}

services/markup/processorhelper_codepreview_test.go

@@ -0,0 +1,60 @@
+// Copyright 2024 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package markup
+
+import (
+	"testing"
+
+	"code.gitea.io/gitea/models/unittest"
+	"code.gitea.io/gitea/modules/markup"
+	"code.gitea.io/gitea/modules/templates"
+	"code.gitea.io/gitea/services/contexttest"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestProcessorHelperCodePreview(t *testing.T) {
+	assert.NoError(t, unittest.PrepareTestDatabase())
+
+	ctx, _ := contexttest.MockContext(t, "/", contexttest.MockContextOption{Render: templates.HTMLRenderer()})
+	htm, err := renderRepoFileCodePreview(ctx, markup.RenderCodePreviewOptions{
+		FullURL:   "http://full",
+		OwnerName: "user2",
+		RepoName:  "repo1",
+		CommitID:  "65f1bf27bc3bf70f64657658635e66094edbcb4d",
+		FilePath:  "/README.md",
+		LineStart: 1,
+		LineStop:  10,
+	})
+	assert.NoError(t, err)
+	assert.Equal(t, `<div class="code-preview-container">
+	<div class="code-preview-header">
+		<a href="http://full" class="muted" rel="nofollow">/README.md</a>
+		Lines 1 to 10 in
+		<a href="/user2/repo1/src/commit/65f1bf27bc3bf70f64657658635e66094edbcb4d" rel="nofollow">65f1bf27bc</a>
+	</div>
+	<table>
+		<tbody><tr>
+				<td class="lines-num"><span data-line-number="1"></span></td>
+				<td class="lines-code chroma"><span class="gh"># repo1</td>
+			</tr><tr>
+				<td class="lines-num"><span data-line-number="2"></span></td>
+				<td class="lines-code chroma"></span><span class="gh"></span></td>
+			</tr></tbody>
+	</table>
+</div>
+`, string(htm))
+
+	ctx, _ = contexttest.MockContext(t, "/", contexttest.MockContextOption{Render: templates.HTMLRenderer()})
+	_, err = renderRepoFileCodePreview(ctx, markup.RenderCodePreviewOptions{
+		FullURL:   "http://full",
+		OwnerName: "user15",
+		RepoName:  "big_test_private_1",
+		CommitID:  "65f1bf27bc3bf70f64657658635e66094edbcb4d",
+		FilePath:  "/README.md",
+		LineStart: 1,
+		LineStop:  10,
+	})
+	assert.ErrorContains(t, err, "no permission")
+}

templates/base/markup_codepreview.tmpl

@@ -0,0 +1,17 @@
+<div class="code-preview-container">
+	<div class="code-preview-header">
+		<a href="{{.FullURL}}" class="muted" rel="nofollow">{{.FilePath}}</a>
+		Lines {{.LineStart}} to {{.LineStop}} in
+		<a href="{{.RepoLink}}/src/commit/{{.CommitID}}" rel="nofollow">{{.CommitID | ShortSha}}</a>
+	</div>
+	<table>
+		<tbody>
+			{{- range .HighlightLines -}}
+			<tr>
+				<td class="lines-num"><span data-line-number="{{.Num}}"></span></td>
+				<td class="lines-code chroma">{{.FormattedContent}}</td>
+			</tr>
+			{{- end -}}
+		</tbody>
+	</table>
+</div>