Render embedded code preview by permlink in markdown (#30234) (#30249)

Backport #30234 by wxiaoguang

The permlink in markdown will be rendered as a code preview block, like GitHub

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

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 +1,117 @@
+// 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/charset"
+	"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, opts.LineStart)
+	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 && line == "" {
+			break
+		} else {
+			lineNums = append(lineNums, i)
+			lineCodes = append(lineCodes, line)
+		}
+	}
+	realLineStop := max(opts.LineStart, opts.LineStart+len(lineNums)-1)
+	highlightLines := code.HighlightSearchResultCode(opts.FilePath, language, lineNums, strings.Join(lineCodes, ""))
+
+	escapeStatus := &charset.EscapeStatus{}
+	lineEscapeStatus := make([]*charset.EscapeStatus, len(highlightLines))
+	for i, hl := range highlightLines {
+		lineEscapeStatus[i], hl.FormattedContent = charset.EscapeControlHTML(hl.FormattedContent, webCtx.Base.Locale, charset.RuneNBSP)
+		escapeStatus = escapeStatus.Or(lineEscapeStatus[i])
+	}
+
+	return webCtx.RenderToHTML("base/markup_codepreview", map[string]any{
+		"FullURL":          opts.FullURL,
+		"FilePath":         opts.FilePath,
+		"LineStart":        opts.LineStart,
+		"LineStop":         realLineStop,
+		"RepoLink":         dbRepo.Link(),
+		"CommitID":         opts.CommitID,
+		"HighlightLines":   highlightLines,
+		"EscapeStatus":     escapeStatus,
+		"LineEscapeStatus": lineEscapeStatus,
+	})
+}

services/markup/processorhelper_codepreview_test.go

@@ -0,0 +1,83 @@
+// 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:  2,
+	})
+	assert.NoError(t, err)
+	assert.Equal(t, `<div class="code-preview-container file-content">
+	<div class="code-preview-header">
+		<a href="http://full" class="muted" rel="nofollow">/README.md</a>
+		repo.code_preview_line_from_to:1,2,<a href="/user2/repo1/src/commit/65f1bf27bc3bf70f64657658635e66094edbcb4d" rel="nofollow">65f1bf27bc</a>
+	</div>
+	<table class="file-view">
+		<tbody><tr>
+				<td class="lines-num"><span data-line-number="1"></span></td>
+				<td class="lines-code chroma"><code class="code-inner"><span class="gh"># repo1</code></td>
+			</tr><tr>
+				<td class="lines-num"><span data-line-number="2"></span></td>
+				<td class="lines-code chroma"><code class="code-inner"></span><span class="gh"></span></code></td>
+			</tr></tbody>
+	</table>
+</div>
+`, string(htm))
+
+	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,
+	})
+	assert.NoError(t, err)
+	assert.Equal(t, `<div class="code-preview-container file-content">
+	<div class="code-preview-header">
+		<a href="http://full" class="muted" rel="nofollow">/README.md</a>
+		repo.code_preview_line_in:1,<a href="/user2/repo1/src/commit/65f1bf27bc3bf70f64657658635e66094edbcb4d" rel="nofollow">65f1bf27bc</a>
+	</div>
+	<table class="file-view">
+		<tbody><tr>
+				<td class="lines-num"><span data-line-number="1"></span></td>
+				<td class="lines-code chroma"><code class="code-inner"><span class="gh"># repo1</code></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")
+}