git.go

@@ -8,17 +8,12 @@ import ( 	"encoding/hex" 	"errors" 	"fmt"-	"html/template" 	"io" 	"io/fs"-	"net/http"-	"net/url" 	"os" 	"os/exec"-	"path" 	"path/filepath" 	"regexp"-	"strconv" 	"strings" 	"time" )@@ -404,84 +399,6 @@ func (t *tree) gitHead(name string) (gitDir, state string) { 	return r.gitDir, r.gitDir + "\n" + r.head(ctx) } -// commitLine is label, a commit's stardate as a history or a commit page-// shows it, with its hash and exact time on hover.-func commitLine(label string, c *commit) string {-	return fmt.Sprintf("<span class=\"date\" title=\"%s %s\">%s</span>", template.HTMLEscapeString(c.short), exact(c.date), template.HTMLEscapeString(label))-}--// starsFor are the stardates of the repo name lies in. A version reads-// its tree's own repo.-func (t *tree) starsFor(ctx context.Context, name string) *stardates {-	if t.at != nil {-		return stardatesIn(ctx, t.dir)-	}-	dir, _, err := t.gitPlace(name)-	if err != nil {-		return nil-	}-	return stardatesIn(ctx, dir)-}--// logLine is the line at the top of a doc or code page in a repo, or ""-// when no commit touched the page. b is the page's file as read.-func (t *tree) logLine(ctx context.Context, name string, b []byte) string {-	if t.at != nil {-		return t.versionLine(ctx, name, false)-	}-	c := t.lastCommit(ctx, name)-	if c == nil {-		return ""-	}-	state := "current"-	if t.pageChanged(ctx, name, b) {-		state = "changed"-	}-	return topLine(c, t.starsFor(ctx, name).label(c), state, "", "", "", "")-}--// topLine is the line at the top of a page in a repo, and the whole line-// is one target: it opens a menu of the page's versions, which loads from-// base?timeline. On the page as it is, the line says only state, current-// or changed, since where the reader is matters more than which commit;-// the commit, by star, its stardate or hash, and subject, is on hover.-// On a version, the line names the commit by star and subject, and now-// and show, links outside the line, lead to the page as it is and to the-// commit's page, which names its full hash. here, when not "", is the URL-// of the version shown, which the menu marks. Without the script the-// menu holds a link to the history.-func topLine(c *commit, star, state, base, here, now, show string) string {-	esc := template.HTMLEscapeString-	what := star + " · " + subjectOf(c)-	// The stardate leads, as it does in histories and the version menu.-	line := fmt.Sprintf("<span class=\"date\" title=\"%s %s\">%s</span> · <span class=\"subject\" title=\"%s %s\">%s</span>",-		esc(c.short), exact(c.date), esc(star), esc(c.short), exact(c.date), esc(subjectOf(c)))-	if state != "" {-		line = fmt.Sprintf("<span class=\"state\" title=\"%s · %s %s\">%s</span>", esc(what), esc(c.short), exact(c.date), state)-	}-	if here != "" {-		here = " data-here=\"" + esc(here) + "\""-	}-	// The links to the page as it is and to the commit float right,-	// before the line, so they stay out of the line's one target.-	out := ""-	if now != "" {-		out = fmt.Sprintf("<a class=\"own now\" href=\"%s\">current</a>\n", esc(now))-	}-	if show != "" {-		out += fmt.Sprintf("<a class=\"own now\" href=\"%s\">commit</a>\n", esc(show))-	}-	// The whole line opens the timeline, so no word labels it; the name-	// shows on hover and is read out first.-	label := "timeline, " + state + ", " + what-	if state == "" {-		label = "timeline, " + what-	}-	return out + fmt.Sprintf("<details class=\"own latest\" data-timeline=\"%s?timeline\"%s>\n<summary title=\"timeline\" aria-label=\"%s\">%s</summary>\n"+-		"<div class=\"versions\"><a href=\"%s?log\">%s</a></div>\n</details>\n",-		esc(base), here, esc(label), line, esc(base), esc(logLabel))-}- // pageChanged reports whether b, the file of the page at name, differs // from its last commit. Git's id for b, against the id HEAD keeps for // the path, answers in microseconds; git status, which took 16 ms on@@ -540,442 +457,3 @@ func (t *tree) changed(ctx context.Context, name string) bool { 	out, err := git(ctx, dir, "status", "--porcelain", "-z", "--", spec) 	return err == nil && len(out) > 0 }--// subjectOf is what a link to a commit says: its subject, or its hash-// when the message is empty, so the link stays visible.-func subjectOf(c *commit) string {-	if c.subject == "" {-		return c.short-	}-	return c.subject-}--// exact is a commit's time to the minute, as hover shows it.-func exact(t time.Time) string {-	return t.Local().Format("2006-01-02 15:04")-}--// serveTimeline lists every version of name, newest first, for the menu-// on its top line: each commit that touched it, by subject and stardate, then-// its history. The newest commit's row leads to the current page and says-// so, unless the page has changes not yet committed; then a row of its-// own leads there and says that. A page whose history the tree's-// versions do not hold, eg in a share or a nested repo, links each-// commit's page instead.-func (t *tree) serveTimeline(w http.ResponseWriter, r *http.Request, name string, dir bool) {-	crumbs := append(t.pageCrumbs(name, dir), crumb{Label: "timeline"})-	title := "timeline " + t.title(name)-	log, err := t.gitLog(r.Context(), name, maxLog+1)-	if err != nil {-		t.render(w, r, http.StatusNotFound, page{Title: title, Crumbs: crumbs, Kind: "error",-			Body: template.HTML("<pre class=\"error\">" + template.HTMLEscapeString(err.Error()) + "</pre>")})-		return-	}-	if len(log) > maxLog {-		log = log[:maxLog]-	}-	rest := below(name, dir)-	versions := t.historyInVersions(r.Context(), name)-	stars := t.starsFor(r.Context(), name)-	esc := template.HTMLEscapeString-	var body strings.Builder-	// Each row leads with its stardate, so they line up down the menu.-	labels := make([]string, len(log))-	for i := range log {-		labels[i] = stars.rowLabel(&log[i])-	}-	body.WriteString("<ol class=\"versions\"" + leadStyle(labels) + ">\n")-	current := (&url.URL{Path: t.prefix + rest}).String()-	clean := versions && !t.changed(r.Context(), name)-	if versions && !clean {-		fmt.Fprintf(&body, "<li><span class=\"date lead\"></span> <a href=\"%s\">current</a> <span class=\"date\">uncommitted changes</span></li>\n", esc(current))-	}-	for i := range log {-		c := &log[i]-		href, also, note := "?commit="+c.hash, "", ""-		if versions {-			href = t.versionURL(stars, c, rest)-		}-		// The current page is the newest commit's version, so its row-		// leads there and is marked on either page.-		if clean && i == 0 {-			href, also, note = current, fmt.Sprintf(" data-also=\"%s\"", esc(href)), " · current"-		}-		if note != "" {-			note = " <span class=\"date\">current</span>"-		}-		fmt.Fprintf(&body, "<li%s><span class=\"date lead\">%s</span> <a href=\"%s\" title=\"%s %s\">%s</a>%s</li>\n",-			also, esc(labels[i]), esc(href), esc(c.short), exact(c.date), esc(subjectOf(c)), note)-	}-	fmt.Fprintf(&body, "<li class=\"log\"><a href=\"?log\">%s</a></li>\n</ol>\n", esc(logLabel))-	t.render(w, r, http.StatusOK, page{Title: title, Crumbs: crumbs, Kind: "timeline", Body: template.HTML(body.String())})-}--// serveLog lists the commits that touched name, newest first, each with-// its hash, date, subject and body.-func (t *tree) serveLog(w http.ResponseWriter, r *http.Request, name string, dir bool) {-	crumbs := append(t.pageCrumbs(name, dir), crumb{Label: logLabel})-	title := "git log " + t.title(name)-	start := time.Now()-	log, err := t.gitLog(r.Context(), name, maxLog+1)-	took := time.Since(start)-	if err != nil {-		t.render(w, r, http.StatusNotFound, page{Title: title, Crumbs: crumbs, Kind: "error",-			Body: template.HTML("<pre class=\"error\">" + template.HTMLEscapeString(err.Error()) + "</pre>")})-		return-	}-	stars := t.starsFor(r.Context(), name)-	esc := template.HTMLEscapeString-	var body strings.Builder-	if len(log) == 0 {-		shown := t.title(name)-		if dir && name != "." {-			shown += "/"-		}-		body.WriteString("<p class=\"own\">No commit touches " + esc(shown) + ".</p>\n")-	}-	if len(log) > maxLog {-		log = log[:maxLog]-		fmt.Fprintf(&body, "<p class=\"own\">The %d newest commits. <code>git log</code> lists the rest.</p>\n", maxLog)-	}-	// git walks every commit back to the ones that touched name, unless-	// the repo's commit-graph tells it which paths each commit changed.-	// www leaves the repo alone and names the command instead. A share-	// says nothing, since its viewer cannot run it.-	if took > slowGit && !t.shared && t.lacksPathFilters(r.Context(), name) {-		fmt.Fprintf(&body, "<p class=\"own\">git took %d ms for this history. "+-			"<code>git commit-graph write --reachable --changed-paths</code> in the repo makes it several times faster.</p>\n",-			took.Milliseconds())-	}-	// Each commit folds out to its message and its diff. The diff comes-	// from the commit page when the fold opens, through the one script;-	// without it, the link in its place opens that page. A row is one-	// target, the fold, so the links to the commit and its version wait-	// inside it. A local tree links each commit's version of the page:-	// the file or directory as it was then.-	browse := t.historyInVersions(r.Context(), name)-	// Each row leads with its stardate, so they line up down the history.-	labels := make([]string, len(log))-	for i := range log {-		labels[i] = stars.rowLabel(&log[i])-	}-	body.WriteString("<ol class=\"log\"" + leadStyle(labels) + ">\n")-	for i := range log {-		c := &log[i]-		show := esc("?commit=" + c.hash)-		then := ""-		if browse {-			then = fmt.Sprintf(" · <a class=\"then\" href=\"%s\">browse</a>", esc(t.versionURL(stars, c, below(name, dir))))-		}-		fmt.Fprintf(&body, "<li><details data-diff=\"%s\">\n<summary><span class=\"own lead\">%s</span> <span class=\"subject\">%s</span></summary>\n"+-			"<p class=\"own links\">commit <a href=\"%s\">%s</a>%s</p>\n",-			show, commitLine(labels[i], c), esc(c.subject), show, esc(c.hash), then)-		for _, para := range paragraphs(c.body) {-			body.WriteString("<p>" + para + "</p>\n")-		}-		fmt.Fprintf(&body, "<div class=\"diffs\"><p class=\"own\"><a href=\"%s\">diff</a></p></div>\n</details></li>\n", show)-	}-	body.WriteString("</ol>\n")-	t.render(w, r, http.StatusOK, page{Title: title, Crumbs: crumbs, Kind: "log", Body: template.HTML(body.String())})-}--// pageCrumbs are the crumbs of the page at name, the last a link back to-// it, for a page that hangs below it.-func (t *tree) pageCrumbs(name string, dir bool) []crumb {-	crumbs := t.crumbs(name)-	href := name-	switch {-	case name == ".":-		href = ""-	case dir:-		href += "/"-	}-	crumbs[len(crumbs)-1].Href = (&url.URL{Path: t.prefix + href}).String()-	return crumbs-}--// maxDiff caps the bytes of diff a commit page shows.-const maxDiff = 1 << 20--var hexHash = regexp.MustCompile(`^[0-9a-f]{4,64}$`)--// fileDiff is one file's part of a commit's diff: its name in the tree-// and the diff's lines below git's header. A file whose type changed has-// two.-type fileDiff struct {-	name  string // relative to the tree-	rel   string // relative to where git runs-	lines []string-}--// gitShow reads the commit that hash names and its diff, limited to name.-// A share leaves out files whose names begin with a dot. cut reports a-// diff cut at maxDiff.-func (t *tree) gitShow(ctx context.Context, name, hash string) (c *commit, diffs []fileDiff, cut bool, err error) {-	dir, spec, err := t.gitPlace(name)-	if err != nil {-		return nil, nil, false, t.gitErr(err)-	}-	if t.shared && !openRepo(ctx, dir) {-		return nil, nil, false, errNoHistory-	}-	// A commit never changes, so its diff is kept under its full hash.-	var key string-	if r := repoAt(ctx, dir); r.complaint == "" && fullHash(hash) {-		key = fmt.Sprintf("show\x00%s\x00%s\x00%s\x00%s\x00%s\x00%t", r.gitDir, dir, spec, name, hash, t.shared)-		if v, ok := gitCache.get(key); ok {-			s := v.(shown)-			return &s.c, s.diffs, s.cut, nil-		}-	}-	// ^{commit} refuses a blob or a tree, which would show a file's text.-	rev := hash + "^{commit}"-	show := func(args ...string) ([]byte, error) {-		args = append([]string{"show", "--no-ext-diff", "--no-textconv", "--no-show-signature", "--no-color",-			"--no-renames", "--diff-merges=first-parent", "--relative", "--src-prefix=a/", "--dst-prefix=b/"}, args...)-		return git(ctx, dir, args...)-	}-	out, err := show("-s", "-z", "--format="+commitFormat, rev, "--")-	if err != nil {-		return nil, nil, false, t.gitErr(err)-	}-	log := t.commits(out)-	if len(log) == 0 {-		return nil, nil, false, t.gitErr(errors.New("no commit " + hash))-	}-	out, err = show("--format=", "--patch", rev, "--", spec)-	if err != nil {-		return nil, nil, false, t.gitErr(err)-	}-	if len(out) > maxDiff {-		out, cut = out[:bytes.LastIndexByte(out[:maxDiff], '\n')+1], true-	}-	for _, b := range strings.Split("\n"+string(out), "\ndiff --git ")[1:] {-		head, _, _ := strings.Cut(b, "\n")-		f, ok := diffName(head)-		if !ok || t.shared && hasDotName(f) {-			continue-		}-		rel := f-		switch {-		case spec != ".":-			f = name-		case name != ".":-			f = path.Join(name, f)-		}-		diffs = append(diffs, fileDiff{name: f, rel: rel, lines: diffLines(b)})-	}-	if key != "" {-		c := log[0]-		size := int64(len(c.hash)+len(c.short)+len(c.subject)+len(c.body)) + 64-		for _, d := range diffs {-			size += int64(len(d.name)) + 16-			for _, l := range d.lines {-				size += int64(len(l)) + 16-			}-		}-		gitCache.put(key, shown{c, diffs, cut}, size)-	}-	return &log[0], diffs, cut, nil-}--// shown is a commit and its diff as gitShow keeps them.-type shown struct {-	c     commit-	diffs []fileDiff-	cut   bool-}--// fullHash reports whether hash is a whole SHA-1 or SHA-256 name in hex,-// which no later commit can make ambiguous.-func fullHash(hash string) bool {-	if len(hash) != 40 && len(hash) != 64 {-		return false-	}-	return !strings.ContainsFunc(hash, func(r rune) bool { return !(r >= '0' && r <= '9' || r >= 'a' && r <= 'f') })-}--// diffName reads the file's name from the header of its diff, a/name-// b/name, which git quotes as C does when the name holds a quote, a-// backslash or a control character. Without renames both names are one.-func diffName(head string) (string, bool) {-	if !strings.HasPrefix(head, `"`) {-		n := (len(head) - len("a/ b/")) / 2-		if n < 1 || !strings.HasPrefix(head, "a/") {-			return "", false-		}-		return head[2 : 2+n], true-	}-	for i := 1; i < len(head); i++ {-		switch head[i] {-		case '\\':-			i++-		case '"':-			f, err := strconv.Unquote(head[:i+1])-			return strings.TrimPrefix(f, "a/"), err == nil && strings.HasPrefix(f, "a/")-		}-	}-	return "", false-}--// diffLines drops the header git puts above a file's diff, which names-// the file again, and keeps the lines that say what kind of change it is.-func diffLines(block string) []string {-	var out []string-	lines := strings.Split(strings.TrimSuffix(block, "\n"), "\n")[1:]-	for i, line := range lines {-		if strings.HasPrefix(line, "@@") {-			return append(out, lines[i:]...)-		}-		switch {-		case strings.HasPrefix(line, "index "), strings.HasPrefix(line, "--- "), strings.HasPrefix(line, "+++ "):-		case strings.HasPrefix(line, "Binary files "):-			out = append(out, "Binary file changed")-		default:-			out = append(out, line)-		}-	}-	return out-}--// serveCommit shows the commit that hash names: its message and its diff-// limited to name, with a link to the diff across the whole tree. A-// history's fold takes the diff from div.diffs.-func (t *tree) serveCommit(w http.ResponseWriter, r *http.Request, name string, dir bool, hash string) {-	crumbs := t.pageCrumbs(name, dir)-	crumbs = append(crumbs, crumb{Label: logLabel, Href: crumbs[len(crumbs)-1].Href + "?log"}, crumb{Label: hash})-	title := "git show " + hash + " " + t.title(name)-	fail := func(err error) {-		t.render(w, r, http.StatusNotFound, page{Title: title, Crumbs: crumbs, Kind: "error",-			Body: template.HTML("<pre class=\"error\">" + template.HTMLEscapeString(err.Error()) + "</pre>")})-	}-	if !hexHash.MatchString(hash) {-		fail(errors.New("Not a commit hash: " + hash))-		return-	}-	c, diffs, cut, err := t.gitShow(r.Context(), name, hash)-	if err != nil {-		fail(err)-		return-	}-	crumbs[len(crumbs)-1].Label = c.short-	esc := template.HTMLEscapeString-	var body strings.Builder-	// The commit's full hash follows its stardate as plain text, so it-	// can be selected and given to git.-	fmt.Fprintf(&body, "<div class=\"commit\">\n<p class=\"own\">%s · <span class=\"hash\">%s</span></p>\n<p class=\"subject\">%s</p>\n", commitLine(t.starsFor(r.Context(), name).label(c), c), esc(c.hash), esc(c.subject))-	for _, para := range paragraphs(c.body) {-		body.WriteString("<p>" + para + "</p>\n")-	}-	body.WriteString("</div>\n")-	// The semantic diff comes inline when it is kept or asked for with-	// &semantic; otherwise the page asks for it once it shows the plain-	// diff.-	var sem *semantic-	_, asked := r.URL.Query()["semantic"]-	if key := t.semanticKey(name, c.hash); key != "" {-		if v, ok := semanticCache.get(key); ok {-			sem = v.(*semantic)-		}-	}-	if sem == nil && asked {-		sem = t.semanticDiff(r.Context(), name, c.hash, diffs)-	}-	switch {-	case sem != nil:-		body.WriteString(t.semanticHTML(r.URL.Path, c, sem))-	case len(diffs) > 0:-		q := r.URL.Query()-		q.Set("commit", c.hash)-		q.Set("semantic", "")-		fmt.Fprintf(&body, "<div class=\"semantic\" data-src=\"%s\"><p class=\"own\">reading declarations</p></div>\n", esc((&url.URL{Path: r.URL.Path, RawQuery: q.Encode()}).String()))-	}-	body.WriteString("<div class=\"diffs\">\n")-	all := (&url.URL{Path: t.prefix, RawQuery: "commit=" + c.hash}).String()-	shown := name-	if dir {-		shown += "/"-	}-	switch {-	case name != "." && len(diffs) == 0:-		fmt.Fprintf(&body, "<p class=\"own\">It does not change %s. <a href=\"%s\">All files</a></p>\n", esc(shown), esc(all))-	case name != ".":-		fmt.Fprintf(&body, "<p class=\"own\">Changes to %s. <a href=\"%s\">All files</a></p>\n", esc(shown), esc(all))-	case len(diffs) == 0:-		body.WriteString("<p class=\"own\">It changes no file here.</p>\n")-	}-	for _, d := range diffs {-		label := esc(d.name)-		if _, err := fs.Stat(t.fsys, d.name); err == nil {-			label = fmt.Sprintf("<a href=\"%s\">%s</a>", esc((&url.URL{Path: t.prefix + d.name}).String()), label)-		}-		var marks map[int][][2]int-		if sem != nil {-			marks = sem.marks[d.name]-		}-		fmt.Fprintf(&body, "<p class=\"own file\">%s</p>\n%s", label, diffPre(d.lines, marks))-	}-	if cut {-		fmt.Fprintf(&body, "<p class=\"own\">The diff stops at %d KiB. <code>git show %s</code> shows the rest.</p>\n", maxDiff>>10, esc(c.short))-	}-	body.WriteString("</div>\n")-	t.render(w, r, http.StatusOK, page{Title: title, Crumbs: crumbs, Kind: "commit", Body: template.HTML(body.String())})-}--// diffPre renders a diff's lines, each a block tinted by its kind, with-// the changed byte ranges marks gives by line index.-func diffPre(lines []string, marks map[int][][2]int) string {-	var b strings.Builder-	b.WriteString("<pre class=\"diff\">")-	for i, line := range lines {-		class := "meta"-		switch {-		case strings.HasPrefix(line, "@@"):-			class = "hunk"-		case strings.HasPrefix(line, "+"):-			class = "add"-		case strings.HasPrefix(line, "-"):-			class = "del"-		case strings.HasPrefix(line, " "):-			class = "same"-		}-		fmt.Fprintf(&b, "<span class=\"%s\">%s</span>", class, markLine(line, marks[i]))-	}-	b.WriteString("</pre>\n")-	return b.String()-}--// paragraphs splits a commit body at blank lines and joins the lines of-// each, since most bodies are wrapped by hand to 72 columns. A line that-// starts a list item or is indented keeps its own line.-func paragraphs(body string) []string {-	var out []string-	for _, para := range strings.Split(body, "\n\n") {-		var b strings.Builder-		for i, line := range strings.Split(strings.Trim(para, "\n"), "\n") {-			if i > 0 {-				if listLine(line) {-					b.WriteString("<br>")-				} else {-					b.WriteString(" ")-				}-			}-			b.WriteString(template.HTMLEscapeString(strings.TrimRight(line, " \t")))-		}-		if b.Len() > 0 {-			out = append(out, b.String())-		}-	}-	return out-}--func listLine(line string) bool {-	if line == "" || line[0] == ' ' || line[0] == '\t' {-		return true-	}-	if strings.HasPrefix(line, "- ") || strings.HasPrefix(line, "* ") || strings.HasPrefix(line, "+ ") {-		return true-	}-	num := strings.TrimLeft(line, "0123456789")-	return len(num) < len(line) && (strings.HasPrefix(num, ". ") || strings.HasPrefix(num, ") "))-}

git_test.go

@@ -2,13 +2,11 @@ package main  import ( 	"fmt"-	"net/http" 	"os" 	"os/exec" 	"path/filepath" 	"strings" 	"testing"-	"time" )  func needGit(t *testing.T) {@@ -46,170 +44,6 @@ func repoTree(t *testing.T) (*server, string) { 	return s, dir } -// A tracked directory's listing opens its history from its first entry.-func TestListingLeadsToHistory(t *testing.T) {-	s, _ := repoTree(t)-	h := s.handler()-	entry := `<ul class="listing">` + "\n" + `<li class="log"><a href="?log">&lt;(git log)</a></li>`-	for _, p := range []string{"/", "/a/"} {-		if body := get(h, p).Body.String(); !strings.Contains(body, entry) {-			t.Errorf("%s: no history entry first:\n%s", p, body)-		}-	}-	if body := get(h, "/untracked/").Body.String(); strings.Contains(body, "?log") {-		t.Errorf("untracked directory leads to history:\n%s", body)-	}-}--// A directory's history covers its subtree; a file's covers the file.-func TestHistoryPage(t *testing.T) {-	s, dir := repoTree(t)-	h := s.handler()-	rec := get(h, "/?log")-	body := rec.Body.String()-	if rec.Code != http.StatusOK {-		t.Fatalf("status %d:\n%s", rec.Code, body)-	}-	add, ren := strings.Index(body, "Add the docs"), strings.Index(body, "Rename the package &lt;b&gt;")-	if add < 0 || ren < 0 || ren > add {-		t.Errorf("want both commits, newest first:\n%s", body)-	}-	if !strings.Contains(body, "<p>The first line wraps here.<br>- a list item<br>- another</p>\n<p>A second paragraph.</p>") {-		t.Errorf("body not in paragraphs:\n%s", body)-	}-	if !strings.Contains(body, `<span>&lt;(git log)</span>`) {-		t.Errorf("no history crumb:\n%s", body)-	}-	// Each commit folds; its diff loads from the commit page, which the-	// fold also links in its place.-	c := head(t, dir, "HEAD")-	for _, want := range []string{-		`<li><details data-diff="?commit=` + c + `">` + "\n<summary><span class=\"own lead\"><span class=\"date\" title=\"" + c[:7],-		`</span></span> <span class="subject">Rename the package &lt;b&gt;</span></summary>` + "\n" + `<p class="own links">commit <a href="?commit=` + c + `">` + c + `</a> · <a class="then"`,-		`<div class="diffs"><p class="own"><a href="?commit=` + c + `">diff</a></p></div>` + "\n</details></li>",-	} {-		if !strings.Contains(body, want) {-			t.Errorf("no %q:\n%s", want, body)-		}-	}-	if body := get(h, "/index.md?log").Body.String(); strings.Contains(body, "Rename") || !strings.Contains(body, "Add the docs") {-		t.Errorf("file history holds other files' commits:\n%s", body)-	}-	if body := get(h, "/.gitignore?log").Body.String(); !strings.Contains(body, `<a href="/.gitignore">.gitignore</a>`) {-		t.Errorf("dot file's crumb lost its dot:\n%s", body)-	}-	if body := get(h, "/a/b.go?log").Body.String(); !strings.Contains(body, "Rename") || !strings.Contains(body, `<a href="/a/b.go">b.go</a>`) {-		t.Errorf("file history:\n%s", body)-	}-	if body := get(h, "/untracked/?log").Body.String(); !strings.Contains(body, "No commit touches untracked/.") {-		t.Errorf("untracked history:\n%s", body)-	}-}--// A commit with no message still folds: its line holds the hash and date-// alone. A message without a blank line is all subject.-func TestHistoryOddMessages(t *testing.T) {-	s, dir := repoTree(t)-	os.WriteFile(filepath.Join(dir, "index.md"), []byte("# Changed\n"), 0o644)-	if out, err := exec.Command("git", "-C", dir, "-c", "user.name=t", "-c", "user.email=t@x",-		"commit", "-qa", "--allow-empty-message", "-m", "").CombinedOutput(); err != nil {-		t.Fatalf("git commit: %v\n%s", err, out)-	}-	os.WriteFile(filepath.Join(dir, "index.md"), []byte("# Again\n"), 0o644)-	commitAll(t, dir, "One paragraph\nthat runs on")-	body := get(s.handler(), "/index.md?log").Body.String()-	empty, long := head(t, dir, "HEAD~1"), head(t, dir, "HEAD")-	for _, want := range []string{-		`<details data-diff="?commit=` + empty + `">`,-		`</span></span> <span class="subject"></span></summary>`,-		`<details data-diff="?commit=` + long + `">`,-		`</span></span> <span class="subject">One paragraph that runs on</span></summary>`,-	} {-		if !strings.Contains(body, want) {-			t.Errorf("no %q:\n%s", want, body)-		}-	}-}--// A directory without its slash keeps ?log through the redirect.-func TestHistoryRedirectKeepsQuery(t *testing.T) {-	s, _ := repoTree(t)-	if rec := get(s.handler(), "/a?log"); rec.Header().Get("Location") != "/a/?log" {-		t.Errorf("redirect to %q", rec.Header().Get("Location"))-	}-}--// Doc and code pages say at the top whether they match their last-// commit, which they name on hover; an edit since makes them changed.-func TestPageTopNamesLastCommit(t *testing.T) {-	s, dir := repoTree(t)-	h := s.handler()-	for p, subject := range map[string]string{"/index.md": "Add the docs", "/a/b.go": "Rename the package &lt;b&gt;"} {-		body := get(h, p).Body.String()-		if !strings.Contains(body, `<details class="own latest" data-timeline="?timeline">`) || !strings.Contains(body, ` · `+subject+` · `) || !strings.Contains(body, `">current</span></summary>`) ||-			!strings.Contains(body, `<div class="versions"><a href="?log">&lt;(git log)</a></div>`) || strings.Contains(body, `class="own now"`) {-			t.Errorf("%s: no top line with %q:\n%s", p, subject, body)-		}-	}-	if id := head(t, dir, "HEAD:a/b.go"); blobID([]byte("package b\n"), len(id)) != id {-		t.Errorf("blob id %s, git says %s", blobID([]byte("package b\n"), len(id)), id)-	}-	os.WriteFile(filepath.Join(dir, "a", "b.go"), []byte("package c\n"), 0o644)-	if body := get(h, "/a/b.go").Body.String(); !strings.Contains(body, `">changed</span></summary>`) {-		t.Errorf("edited page is not changed:\n%s", body)-	}-	if body := get(h, "/untracked/x.txt").Body.String(); strings.Contains(body, "?log") {-		t.Errorf("untracked file has a top line:\n%s", body)-	}-}--// Outside a repo nothing leads to history, and the page says why.-func TestNoRepoNoHistory(t *testing.T) {-	needGit(t)-	s, _, _ := serveTree(t)-	h := s.handler()-	if body := get(h, "/").Body.String(); strings.Contains(body, "?log") {-		t.Errorf("history entry outside a repo:\n%s", body)-	}-	if rec := get(h, "/?log"); rec.Code != http.StatusNotFound || !strings.Contains(rec.Body.String(), "not a git repository") {-		t.Errorf("status %d:\n%s", rec.Code, rec.Body.String())-	}-}--// A share shows history without trailers, and only while other users-// could read the repo. Its errors name no path.-func TestShareShowsHistory(t *testing.T) {-	needGit(t)-	s := shareTree(t)-	dir := s.list()[0].dir-	if s.list()[0].secret {-		dir = s.list()[1].dir-	}-	exec.Command("git", "init", "-q", dir).Run()-	commitAll(t, dir, "Shared subject\n\nThe body.\n\nClaude-Session: https://claude.ai/code/session_x\nSigned-off-by: t <t@x>")-	gitDir := filepath.Join(dir, ".git")-	exec.Command("chmod", "-R", "go+rX", gitDir).Run()-	h := s.handler()-	if body := get(h, "/docs/").Body.String(); !strings.Contains(body, `href="?log"`) {-		t.Errorf("share listing leads to no history:\n%s", body)-	}-	body := get(h, "/docs/?log").Body.String()-	if !strings.Contains(body, "Shared subject") || !strings.Contains(body, "<p>The body.</p>") {-		t.Errorf("share history:\n%s", body)-	}-	if strings.Contains(body, "claude.ai") || strings.Contains(body, "t@x") {-		t.Errorf("share history shows trailers:\n%s", body)-	}-	os.Chmod(filepath.Join(gitDir, "objects"), 0o700)-	if body := get(h, "/docs/").Body.String(); strings.Contains(body, "?log") {-		t.Errorf("history of a closed repo:\n%s", body)-	}-	rec := get(h, "/docs/?log")-	if rec.Code != http.StatusNotFound || !strings.Contains(rec.Body.String(), "No git history here.") || strings.Contains(rec.Body.String(), dir) {-		t.Errorf("closed repo: %d\n%s", rec.Code, rec.Body.String())-	}-}- // Loopback keeps trailers. func TestLoopbackKeepsTrailers(t *testing.T) { 	s, dir := repoTree(t)@@ -236,20 +70,6 @@ func TestDropTrailers(t *testing.T) { 	} } -// A commit reloads an open history page.-func TestLiveReloadsOnCommit(t *testing.T) {-	needGit(t)-	s, _, dir, ts := liveTree(t)-	exec.Command("git", "init", "-q", dir).Run()-	commitAll(t, dir, "First")-	lines := stream(t, s, ts, "/a/")-	time.Sleep(50 * time.Millisecond)-	exec.Command("git", "-C", dir, "-c", "user.name=t", "-c", "user.email=t@x", "commit", "-q", "--allow-empty", "-m", "Second").Run()-	if !reloads(lines, 2*time.Second) {-		t.Fatal("no reload after a commit")-	}-}- // head is the hash of HEAD in dir. func head(t *testing.T, dir, rev string) string { 	t.Helper()@@ -260,104 +80,6 @@ func head(t *testing.T, dir, rev string) string { 	return strings.TrimSpace(string(out)) } -// A commit page shows the message and the diff of the path it came from,-// and links to the commit across the tree.-func TestCommitPage(t *testing.T) {-	s, dir := repoTree(t)-	h := s.handler()-	c := head(t, dir, "HEAD")-	body := get(h, "/a/b.go?commit="+c).Body.String()-	for _, want := range []string{-		"Rename the package &lt;b&gt;",-		`</span> · <span class="hash">` + c + `</span></p>`,-		`<span class="del">-func F() {}</span><span class="add">+package b</span>`,-		`<a href="/?commit=` + c + `">All files</a>`,-		`<p class="own file"><a href="/a/b.go">a/b.go</a></p>`,-		`<a href="/a/b.go?log">&lt;(git log)</a>`,-		"</div>\n<div class=\"diffs\">\n<p class=\"own\">Changes to a/b.go.",-		"</pre>\n</div>\n",-	} {-		if !strings.Contains(body, want) {-			t.Errorf("no %q:\n%s", want, body)-		}-	}-	if body := get(h, "/index.md?commit="+c).Body.String(); !strings.Contains(body, "It does not change index.md.") {-		t.Errorf("commit that skips the file:\n%s", body)-	}-	first := get(h, "/?commit="+head(t, dir, "HEAD~1")).Body.String()-	if !strings.Contains(first, `<a href="/index.md">index.md</a>`) || !strings.Contains(first, `<a href="/a/b.go">a/b.go</a>`) || strings.Contains(first, "All files") {-		t.Errorf("whole commit:\n%s", first)-	}-	for _, bad := range []string{"zz", "-p", head(t, dir, "HEAD:a/b.go")} {-		if rec := get(h, "/?commit="+bad); rec.Code != http.StatusNotFound {-			t.Errorf("%s: status %d:\n%s", bad, rec.Code, rec.Body.String())-		}-	}-}--func TestDiffName(t *testing.T) {-	for in, want := range map[string]string{-		"a/x.md b/x.md":                     "x.md",-		"a/two words b/two words":           "two words",-		`"a/q\"uote" "b/q\"uote"`:           `q"uote`,-		`"a/tab\there.md" "b/tab\there.md"`: "tab\there.md",-	} {-		if got, ok := diffName(in); !ok || got != want {-			t.Errorf("%q: %q %v, want %q", in, got, ok, want)-		}-	}-}--// A share's diffs leave out dot files.-func TestShareDiffSkipsDots(t *testing.T) {-	needGit(t)-	s := shareTree(t)-	dir := s.list()[0].dir-	if s.list()[0].secret {-		dir = s.list()[1].dir-	}-	exec.Command("git", "init", "-q", dir).Run()-	os.WriteFile(filepath.Join(dir, ".env"), []byte("TOKEN=hidden\n"), 0o644)-	commitAll(t, dir, "Shared")-	exec.Command("chmod", "-R", "go+rX", filepath.Join(dir, ".git")).Run()-	body := get(s.handler(), "/docs/?commit="+head(t, dir, "HEAD")).Body.String()-	if !strings.Contains(body, "+docs/pub.txt") || strings.Contains(body, "hidden") {-		t.Errorf("share diff:\n%s", body)-	}-}--// A history that git was slow to give names the command that writes-// changed-path filters, until the repo has them. A share never names it.-func TestSlowHistoryNamesCommitGraph(t *testing.T) {-	s, dir := repoTree(t)-	h := s.handler()-	defer func(d time.Duration) { slowGit = d }(slowGit)-	slowGit = -1-	hint := "git commit-graph write --reachable --changed-paths"-	if body := get(h, "/?log").Body.String(); !strings.Contains(body, hint) {-		t.Errorf("no hint without filters:\n%s", body)-	}-	if out, err := exec.Command("git", "-C", dir, "commit-graph", "write", "--reachable", "--changed-paths").CombinedOutput(); err != nil {-		t.Fatalf("commit-graph: %v\n%s", err, out)-	}-	if body := get(h, "/index.md?log").Body.String(); strings.Contains(body, hint) {-		t.Errorf("hint with filters:\n%s", body)-	}-	os.Remove(filepath.Join(dir, ".git", "objects", "info", "commit-graph"))-	if out, err := exec.Command("git", "-C", dir, "commit-graph", "write", "--reachable", "--split").CombinedOutput(); err != nil {-		t.Fatalf("commit-graph: %v\n%s", err, out)-	}-	if body := get(h, "/a/?log").Body.String(); !strings.Contains(body, hint) {-		t.Errorf("no hint for a split graph without filters:\n%s", body)-	}-	if out, err := exec.Command("git", "-C", dir, "commit-graph", "write", "--reachable", "--split=replace", "--changed-paths").CombinedOutput(); err != nil {-		t.Fatalf("commit-graph: %v\n%s", err, out)-	}-	if body := get(h, "/a/b.go?log").Body.String(); strings.Contains(body, hint) {-		t.Errorf("hint for a split graph with filters:\n%s", body)-	}-}- // A new tree's listing and README have their top lines cached before the // first visit. func TestWarmCachesFirstPages(t *testing.T) {

historypage.go

new file mode 100644@@ -0,0 +1,534 @@+package main++import (+	"bytes"+	"context"+	"errors"+	"fmt"+	"html/template"+	"io/fs"+	"net/http"+	"net/url"+	"path"+	"regexp"+	"strconv"+	"strings"+	"time"+)++// commitLine is label, a commit's stardate as a history or a commit page+// shows it, with its hash and exact time on hover.+func commitLine(label string, c *commit) string {+	return fmt.Sprintf("<span class=\"date\" title=\"%s %s\">%s</span>", template.HTMLEscapeString(c.short), exact(c.date), template.HTMLEscapeString(label))+}++// starsFor are the stardates of the repo name lies in. A version reads+// its tree's own repo.+func (t *tree) starsFor(ctx context.Context, name string) *stardates {+	if t.at != nil {+		return stardatesIn(ctx, t.dir)+	}+	dir, _, err := t.gitPlace(name)+	if err != nil {+		return nil+	}+	return stardatesIn(ctx, dir)+}++// logLine is the line at the top of a doc or code page in a repo, or ""+// when no commit touched the page. b is the page's file as read.+func (t *tree) logLine(ctx context.Context, name string, b []byte) string {+	if t.at != nil {+		return t.versionLine(ctx, name, false)+	}+	c := t.lastCommit(ctx, name)+	if c == nil {+		return ""+	}+	state := "current"+	if t.pageChanged(ctx, name, b) {+		state = "changed"+	}+	return topLine(c, t.starsFor(ctx, name).label(c), state, "", "", "", "")+}++// topLine is the line at the top of a page in a repo, and the whole line+// is one target: it opens a menu of the page's versions, which loads from+// base?timeline. On the page as it is, the line says only state, current+// or changed, since where the reader is matters more than which commit;+// the commit, by star, its stardate or hash, and subject, is on hover.+// On a version, the line names the commit by star and subject, and now+// and show, links outside the line, lead to the page as it is and to the+// commit's page, which names its full hash. here, when not "", is the URL+// of the version shown, which the menu marks. Without the script the+// menu holds a link to the history.+func topLine(c *commit, star, state, base, here, now, show string) string {+	esc := template.HTMLEscapeString+	what := star + " · " + subjectOf(c)+	// The stardate leads, as it does in histories and the version menu.+	line := fmt.Sprintf("<span class=\"date\" title=\"%s %s\">%s</span> · <span class=\"subject\" title=\"%s %s\">%s</span>",+		esc(c.short), exact(c.date), esc(star), esc(c.short), exact(c.date), esc(subjectOf(c)))+	if state != "" {+		line = fmt.Sprintf("<span class=\"state\" title=\"%s · %s %s\">%s</span>", esc(what), esc(c.short), exact(c.date), state)+	}+	if here != "" {+		here = " data-here=\"" + esc(here) + "\""+	}+	// The links to the page as it is and to the commit float right,+	// before the line, so they stay out of the line's one target.+	out := ""+	if now != "" {+		out = fmt.Sprintf("<a class=\"own now\" href=\"%s\">current</a>\n", esc(now))+	}+	if show != "" {+		out += fmt.Sprintf("<a class=\"own now\" href=\"%s\">commit</a>\n", esc(show))+	}+	// The whole line opens the timeline, so no word labels it; the name+	// shows on hover and is read out first.+	label := "timeline, " + state + ", " + what+	if state == "" {+		label = "timeline, " + what+	}+	return out + fmt.Sprintf("<details class=\"own latest\" data-timeline=\"%s?timeline\"%s>\n<summary title=\"timeline\" aria-label=\"%s\">%s</summary>\n"++		"<div class=\"versions\"><a href=\"%s?log\">%s</a></div>\n</details>\n",+		esc(base), here, esc(label), line, esc(base), esc(logLabel))+}++// subjectOf is what a link to a commit says: its subject, or its hash+// when the message is empty, so the link stays visible.+func subjectOf(c *commit) string {+	if c.subject == "" {+		return c.short+	}+	return c.subject+}++// exact is a commit's time to the minute, as hover shows it.+func exact(t time.Time) string {+	return t.Local().Format("2006-01-02 15:04")+}++// serveTimeline lists every version of name, newest first, for the menu+// on its top line: each commit that touched it, by subject and stardate, then+// its history. The newest commit's row leads to the current page and says+// so, unless the page has changes not yet committed; then a row of its+// own leads there and says that. A page whose history the tree's+// versions do not hold, eg in a share or a nested repo, links each+// commit's page instead.+func (t *tree) serveTimeline(w http.ResponseWriter, r *http.Request, name string, dir bool) {+	crumbs := append(t.pageCrumbs(name, dir), crumb{Label: "timeline"})+	title := "timeline " + t.title(name)+	log, err := t.gitLog(r.Context(), name, maxLog+1)+	if err != nil {+		t.render(w, r, http.StatusNotFound, page{Title: title, Crumbs: crumbs, Kind: "error",+			Body: template.HTML("<pre class=\"error\">" + template.HTMLEscapeString(err.Error()) + "</pre>")})+		return+	}+	if len(log) > maxLog {+		log = log[:maxLog]+	}+	rest := below(name, dir)+	versions := t.historyInVersions(r.Context(), name)+	stars := t.starsFor(r.Context(), name)+	esc := template.HTMLEscapeString+	var body strings.Builder+	// Each row leads with its stardate, so they line up down the menu.+	labels := make([]string, len(log))+	for i := range log {+		labels[i] = stars.rowLabel(&log[i])+	}+	body.WriteString("<ol class=\"versions\"" + leadStyle(labels) + ">\n")+	current := (&url.URL{Path: t.prefix + rest}).String()+	clean := versions && !t.changed(r.Context(), name)+	if versions && !clean {+		fmt.Fprintf(&body, "<li><span class=\"date lead\"></span> <a href=\"%s\">current</a> <span class=\"date\">uncommitted changes</span></li>\n", esc(current))+	}+	for i := range log {+		c := &log[i]+		href, also, note := "?commit="+c.hash, "", ""+		if versions {+			href = t.versionURL(stars, c, rest)+		}+		// The current page is the newest commit's version, so its row+		// leads there and is marked on either page.+		if clean && i == 0 {+			href, also, note = current, fmt.Sprintf(" data-also=\"%s\"", esc(href)), " · current"+		}+		if note != "" {+			note = " <span class=\"date\">current</span>"+		}+		fmt.Fprintf(&body, "<li%s><span class=\"date lead\">%s</span> <a href=\"%s\" title=\"%s %s\">%s</a>%s</li>\n",+			also, esc(labels[i]), esc(href), esc(c.short), exact(c.date), esc(subjectOf(c)), note)+	}+	fmt.Fprintf(&body, "<li class=\"log\"><a href=\"?log\">%s</a></li>\n</ol>\n", esc(logLabel))+	t.render(w, r, http.StatusOK, page{Title: title, Crumbs: crumbs, Kind: "timeline", Body: template.HTML(body.String())})+}++// serveLog lists the commits that touched name, newest first, each with+// its hash, date, subject and body.+func (t *tree) serveLog(w http.ResponseWriter, r *http.Request, name string, dir bool) {+	crumbs := append(t.pageCrumbs(name, dir), crumb{Label: logLabel})+	title := "git log " + t.title(name)+	start := time.Now()+	log, err := t.gitLog(r.Context(), name, maxLog+1)+	took := time.Since(start)+	if err != nil {+		t.render(w, r, http.StatusNotFound, page{Title: title, Crumbs: crumbs, Kind: "error",+			Body: template.HTML("<pre class=\"error\">" + template.HTMLEscapeString(err.Error()) + "</pre>")})+		return+	}+	stars := t.starsFor(r.Context(), name)+	esc := template.HTMLEscapeString+	var body strings.Builder+	if len(log) == 0 {+		shown := t.title(name)+		if dir && name != "." {+			shown += "/"+		}+		body.WriteString("<p class=\"own\">No commit touches " + esc(shown) + ".</p>\n")+	}+	if len(log) > maxLog {+		log = log[:maxLog]+		fmt.Fprintf(&body, "<p class=\"own\">The %d newest commits. <code>git log</code> lists the rest.</p>\n", maxLog)+	}+	// git walks every commit back to the ones that touched name, unless+	// the repo's commit-graph tells it which paths each commit changed.+	// www leaves the repo alone and names the command instead. A share+	// says nothing, since its viewer cannot run it.+	if took > slowGit && !t.shared && t.lacksPathFilters(r.Context(), name) {+		fmt.Fprintf(&body, "<p class=\"own\">git took %d ms for this history. "++			"<code>git commit-graph write --reachable --changed-paths</code> in the repo makes it several times faster.</p>\n",+			took.Milliseconds())+	}+	// Each commit folds out to its message and its diff. The diff comes+	// from the commit page when the fold opens, through the one script;+	// without it, the link in its place opens that page. A row is one+	// target, the fold, so the links to the commit and its version wait+	// inside it. A local tree links each commit's version of the page:+	// the file or directory as it was then.+	browse := t.historyInVersions(r.Context(), name)+	// Each row leads with its stardate, so they line up down the history.+	labels := make([]string, len(log))+	for i := range log {+		labels[i] = stars.rowLabel(&log[i])+	}+	body.WriteString("<ol class=\"log\"" + leadStyle(labels) + ">\n")+	for i := range log {+		c := &log[i]+		show := esc("?commit=" + c.hash)+		then := ""+		if browse {+			then = fmt.Sprintf(" · <a class=\"then\" href=\"%s\">browse</a>", esc(t.versionURL(stars, c, below(name, dir))))+		}+		fmt.Fprintf(&body, "<li><details data-diff=\"%s\">\n<summary><span class=\"own lead\">%s</span> <span class=\"subject\">%s</span></summary>\n"++			"<p class=\"own links\">commit <a href=\"%s\">%s</a>%s</p>\n",+			show, commitLine(labels[i], c), esc(c.subject), show, esc(c.hash), then)+		for _, para := range paragraphs(c.body) {+			body.WriteString("<p>" + para + "</p>\n")+		}+		fmt.Fprintf(&body, "<div class=\"diffs\"><p class=\"own\"><a href=\"%s\">diff</a></p></div>\n</details></li>\n", show)+	}+	body.WriteString("</ol>\n")+	t.render(w, r, http.StatusOK, page{Title: title, Crumbs: crumbs, Kind: "log", Body: template.HTML(body.String())})+}++// pageCrumbs are the crumbs of the page at name, the last a link back to+// it, for a page that hangs below it.+func (t *tree) pageCrumbs(name string, dir bool) []crumb {+	crumbs := t.crumbs(name)+	href := name+	switch {+	case name == ".":+		href = ""+	case dir:+		href += "/"+	}+	crumbs[len(crumbs)-1].Href = (&url.URL{Path: t.prefix + href}).String()+	return crumbs+}++// maxDiff caps the bytes of diff a commit page shows.+const maxDiff = 1 << 20++var hexHash = regexp.MustCompile(`^[0-9a-f]{4,64}$`)++// fileDiff is one file's part of a commit's diff: its name in the tree+// and the diff's lines below git's header. A file whose type changed has+// two.+type fileDiff struct {+	name  string // relative to the tree+	rel   string // relative to where git runs+	lines []string+}++// gitShow reads the commit that hash names and its diff, limited to name.+// A share leaves out files whose names begin with a dot. cut reports a+// diff cut at maxDiff.+func (t *tree) gitShow(ctx context.Context, name, hash string) (c *commit, diffs []fileDiff, cut bool, err error) {+	dir, spec, err := t.gitPlace(name)+	if err != nil {+		return nil, nil, false, t.gitErr(err)+	}+	if t.shared && !openRepo(ctx, dir) {+		return nil, nil, false, errNoHistory+	}+	// A commit never changes, so its diff is kept under its full hash.+	var key string+	if r := repoAt(ctx, dir); r.complaint == "" && fullHash(hash) {+		key = fmt.Sprintf("show\x00%s\x00%s\x00%s\x00%s\x00%s\x00%t", r.gitDir, dir, spec, name, hash, t.shared)+		if v, ok := gitCache.get(key); ok {+			s := v.(shown)+			return &s.c, s.diffs, s.cut, nil+		}+	}+	// ^{commit} refuses a blob or a tree, which would show a file's text.+	rev := hash + "^{commit}"+	show := func(args ...string) ([]byte, error) {+		args = append([]string{"show", "--no-ext-diff", "--no-textconv", "--no-show-signature", "--no-color",+			"--no-renames", "--diff-merges=first-parent", "--relative", "--src-prefix=a/", "--dst-prefix=b/"}, args...)+		return git(ctx, dir, args...)+	}+	out, err := show("-s", "-z", "--format="+commitFormat, rev, "--")+	if err != nil {+		return nil, nil, false, t.gitErr(err)+	}+	log := t.commits(out)+	if len(log) == 0 {+		return nil, nil, false, t.gitErr(errors.New("no commit " + hash))+	}+	out, err = show("--format=", "--patch", rev, "--", spec)+	if err != nil {+		return nil, nil, false, t.gitErr(err)+	}+	if len(out) > maxDiff {+		out, cut = out[:bytes.LastIndexByte(out[:maxDiff], '\n')+1], true+	}+	for _, b := range strings.Split("\n"+string(out), "\ndiff --git ")[1:] {+		head, _, _ := strings.Cut(b, "\n")+		f, ok := diffName(head)+		if !ok || t.shared && hasDotName(f) {+			continue+		}+		rel := f+		switch {+		case spec != ".":+			f = name+		case name != ".":+			f = path.Join(name, f)+		}+		diffs = append(diffs, fileDiff{name: f, rel: rel, lines: diffLines(b)})+	}+	if key != "" {+		c := log[0]+		size := int64(len(c.hash)+len(c.short)+len(c.subject)+len(c.body)) + 64+		for _, d := range diffs {+			size += int64(len(d.name)) + 16+			for _, l := range d.lines {+				size += int64(len(l)) + 16+			}+		}+		gitCache.put(key, shown{c, diffs, cut}, size)+	}+	return &log[0], diffs, cut, nil+}++// shown is a commit and its diff as gitShow keeps them.+type shown struct {+	c     commit+	diffs []fileDiff+	cut   bool+}++// fullHash reports whether hash is a whole SHA-1 or SHA-256 name in hex,+// which no later commit can make ambiguous.+func fullHash(hash string) bool {+	if len(hash) != 40 && len(hash) != 64 {+		return false+	}+	return !strings.ContainsFunc(hash, func(r rune) bool { return !(r >= '0' && r <= '9' || r >= 'a' && r <= 'f') })+}++// diffName reads the file's name from the header of its diff, a/name+// b/name, which git quotes as C does when the name holds a quote, a+// backslash or a control character. Without renames both names are one.+func diffName(head string) (string, bool) {+	if !strings.HasPrefix(head, `"`) {+		n := (len(head) - len("a/ b/")) / 2+		if n < 1 || !strings.HasPrefix(head, "a/") {+			return "", false+		}+		return head[2 : 2+n], true+	}+	for i := 1; i < len(head); i++ {+		switch head[i] {+		case '\\':+			i+++		case '"':+			f, err := strconv.Unquote(head[:i+1])+			return strings.TrimPrefix(f, "a/"), err == nil && strings.HasPrefix(f, "a/")+		}+	}+	return "", false+}++// diffLines drops the header git puts above a file's diff, which names+// the file again, and keeps the lines that say what kind of change it is.+func diffLines(block string) []string {+	var out []string+	lines := strings.Split(strings.TrimSuffix(block, "\n"), "\n")[1:]+	for i, line := range lines {+		if strings.HasPrefix(line, "@@") {+			return append(out, lines[i:]...)+		}+		switch {+		case strings.HasPrefix(line, "index "), strings.HasPrefix(line, "--- "), strings.HasPrefix(line, "+++ "):+		case strings.HasPrefix(line, "Binary files "):+			out = append(out, "Binary file changed")+		default:+			out = append(out, line)+		}+	}+	return out+}++// serveCommit shows the commit that hash names: its message and its diff+// limited to name, with a link to the diff across the whole tree. A+// history's fold takes the diff from div.diffs.+func (t *tree) serveCommit(w http.ResponseWriter, r *http.Request, name string, dir bool, hash string) {+	crumbs := t.pageCrumbs(name, dir)+	crumbs = append(crumbs, crumb{Label: logLabel, Href: crumbs[len(crumbs)-1].Href + "?log"}, crumb{Label: hash})+	title := "git show " + hash + " " + t.title(name)+	fail := func(err error) {+		t.render(w, r, http.StatusNotFound, page{Title: title, Crumbs: crumbs, Kind: "error",+			Body: template.HTML("<pre class=\"error\">" + template.HTMLEscapeString(err.Error()) + "</pre>")})+	}+	if !hexHash.MatchString(hash) {+		fail(errors.New("Not a commit hash: " + hash))+		return+	}+	c, diffs, cut, err := t.gitShow(r.Context(), name, hash)+	if err != nil {+		fail(err)+		return+	}+	crumbs[len(crumbs)-1].Label = c.short+	esc := template.HTMLEscapeString+	var body strings.Builder+	// The commit's full hash follows its stardate as plain text, so it+	// can be selected and given to git.+	fmt.Fprintf(&body, "<div class=\"commit\">\n<p class=\"own\">%s · <span class=\"hash\">%s</span></p>\n<p class=\"subject\">%s</p>\n", commitLine(t.starsFor(r.Context(), name).label(c), c), esc(c.hash), esc(c.subject))+	for _, para := range paragraphs(c.body) {+		body.WriteString("<p>" + para + "</p>\n")+	}+	body.WriteString("</div>\n")+	// The semantic diff comes inline when it is kept or asked for with+	// &semantic; otherwise the page asks for it once it shows the plain+	// diff.+	var sem *semantic+	_, asked := r.URL.Query()["semantic"]+	if key := t.semanticKey(name, c.hash); key != "" {+		if v, ok := semanticCache.get(key); ok {+			sem = v.(*semantic)+		}+	}+	if sem == nil && asked {+		sem = t.semanticDiff(r.Context(), name, c.hash, diffs)+	}+	switch {+	case sem != nil:+		body.WriteString(t.semanticHTML(r.URL.Path, c, sem))+	case len(diffs) > 0:+		q := r.URL.Query()+		q.Set("commit", c.hash)+		q.Set("semantic", "")+		fmt.Fprintf(&body, "<div class=\"semantic\" data-src=\"%s\"><p class=\"own\">reading declarations</p></div>\n", esc((&url.URL{Path: r.URL.Path, RawQuery: q.Encode()}).String()))+	}+	body.WriteString("<div class=\"diffs\">\n")+	all := (&url.URL{Path: t.prefix, RawQuery: "commit=" + c.hash}).String()+	shown := name+	if dir {+		shown += "/"+	}+	switch {+	case name != "." && len(diffs) == 0:+		fmt.Fprintf(&body, "<p class=\"own\">It does not change %s. <a href=\"%s\">All files</a></p>\n", esc(shown), esc(all))+	case name != ".":+		fmt.Fprintf(&body, "<p class=\"own\">Changes to %s. <a href=\"%s\">All files</a></p>\n", esc(shown), esc(all))+	case len(diffs) == 0:+		body.WriteString("<p class=\"own\">It changes no file here.</p>\n")+	}+	for _, d := range diffs {+		label := esc(d.name)+		if _, err := fs.Stat(t.fsys, d.name); err == nil {+			label = fmt.Sprintf("<a href=\"%s\">%s</a>", esc((&url.URL{Path: t.prefix + d.name}).String()), label)+		}+		var marks map[int][][2]int+		if sem != nil {+			marks = sem.marks[d.name]+		}+		fmt.Fprintf(&body, "<p class=\"own file\">%s</p>\n%s", label, diffPre(d.lines, marks))+	}+	if cut {+		fmt.Fprintf(&body, "<p class=\"own\">The diff stops at %d KiB. <code>git show %s</code> shows the rest.</p>\n", maxDiff>>10, esc(c.short))+	}+	body.WriteString("</div>\n")+	t.render(w, r, http.StatusOK, page{Title: title, Crumbs: crumbs, Kind: "commit", Body: template.HTML(body.String())})+}++// diffPre renders a diff's lines, each a block tinted by its kind, with+// the changed byte ranges marks gives by line index.+func diffPre(lines []string, marks map[int][][2]int) string {+	var b strings.Builder+	b.WriteString("<pre class=\"diff\">")+	for i, line := range lines {+		class := "meta"+		switch {+		case strings.HasPrefix(line, "@@"):+			class = "hunk"+		case strings.HasPrefix(line, "+"):+			class = "add"+		case strings.HasPrefix(line, "-"):+			class = "del"+		case strings.HasPrefix(line, " "):+			class = "same"+		}+		fmt.Fprintf(&b, "<span class=\"%s\">%s</span>", class, markLine(line, marks[i]))+	}+	b.WriteString("</pre>\n")+	return b.String()+}++// paragraphs splits a commit body at blank lines and joins the lines of+// each, since most bodies are wrapped by hand to 72 columns. A line that+// starts a list item or is indented keeps its own line.+func paragraphs(body string) []string {+	var out []string+	for _, para := range strings.Split(body, "\n\n") {+		var b strings.Builder+		for i, line := range strings.Split(strings.Trim(para, "\n"), "\n") {+			if i > 0 {+				if listLine(line) {+					b.WriteString("<br>")+				} else {+					b.WriteString(" ")+				}+			}+			b.WriteString(template.HTMLEscapeString(strings.TrimRight(line, " \t")))+		}+		if b.Len() > 0 {+			out = append(out, b.String())+		}+	}+	return out+}++func listLine(line string) bool {+	if line == "" || line[0] == ' ' || line[0] == '\t' {+		return true+	}+	if strings.HasPrefix(line, "- ") || strings.HasPrefix(line, "* ") || strings.HasPrefix(line, "+ ") {+		return true+	}+	num := strings.TrimLeft(line, "0123456789")+	return len(num) < len(line) && (strings.HasPrefix(num, ". ") || strings.HasPrefix(num, ") "))+}

historypage_test.go

new file mode 100644@@ -0,0 +1,273 @@+package main++import (+	"net/http"+	"os"+	"os/exec"+	"path/filepath"+	"strings"+	"testing"+	"time"+)++// A tracked directory's listing opens its history from its first entry.+func TestListingLeadsToHistory(t *testing.T) {+	s, _ := repoTree(t)+	h := s.handler()+	entry := `<ul class="listing">` + "\n" + `<li class="log"><a href="?log">&lt;(git log)</a></li>`+	for _, p := range []string{"/", "/a/"} {+		if body := get(h, p).Body.String(); !strings.Contains(body, entry) {+			t.Errorf("%s: no history entry first:\n%s", p, body)+		}+	}+	if body := get(h, "/untracked/").Body.String(); strings.Contains(body, "?log") {+		t.Errorf("untracked directory leads to history:\n%s", body)+	}+}++// A directory's history covers its subtree; a file's covers the file.+func TestHistoryPage(t *testing.T) {+	s, dir := repoTree(t)+	h := s.handler()+	rec := get(h, "/?log")+	body := rec.Body.String()+	if rec.Code != http.StatusOK {+		t.Fatalf("status %d:\n%s", rec.Code, body)+	}+	add, ren := strings.Index(body, "Add the docs"), strings.Index(body, "Rename the package &lt;b&gt;")+	if add < 0 || ren < 0 || ren > add {+		t.Errorf("want both commits, newest first:\n%s", body)+	}+	if !strings.Contains(body, "<p>The first line wraps here.<br>- a list item<br>- another</p>\n<p>A second paragraph.</p>") {+		t.Errorf("body not in paragraphs:\n%s", body)+	}+	if !strings.Contains(body, `<span>&lt;(git log)</span>`) {+		t.Errorf("no history crumb:\n%s", body)+	}+	// Each commit folds; its diff loads from the commit page, which the+	// fold also links in its place.+	c := head(t, dir, "HEAD")+	for _, want := range []string{+		`<li><details data-diff="?commit=` + c + `">` + "\n<summary><span class=\"own lead\"><span class=\"date\" title=\"" + c[:7],+		`</span></span> <span class="subject">Rename the package &lt;b&gt;</span></summary>` + "\n" + `<p class="own links">commit <a href="?commit=` + c + `">` + c + `</a> · <a class="then"`,+		`<div class="diffs"><p class="own"><a href="?commit=` + c + `">diff</a></p></div>` + "\n</details></li>",+	} {+		if !strings.Contains(body, want) {+			t.Errorf("no %q:\n%s", want, body)+		}+	}+	if body := get(h, "/index.md?log").Body.String(); strings.Contains(body, "Rename") || !strings.Contains(body, "Add the docs") {+		t.Errorf("file history holds other files' commits:\n%s", body)+	}+	if body := get(h, "/.gitignore?log").Body.String(); !strings.Contains(body, `<a href="/.gitignore">.gitignore</a>`) {+		t.Errorf("dot file's crumb lost its dot:\n%s", body)+	}+	if body := get(h, "/a/b.go?log").Body.String(); !strings.Contains(body, "Rename") || !strings.Contains(body, `<a href="/a/b.go">b.go</a>`) {+		t.Errorf("file history:\n%s", body)+	}+	if body := get(h, "/untracked/?log").Body.String(); !strings.Contains(body, "No commit touches untracked/.") {+		t.Errorf("untracked history:\n%s", body)+	}+}++// A commit with no message still folds: its line holds the hash and date+// alone. A message without a blank line is all subject.+func TestHistoryOddMessages(t *testing.T) {+	s, dir := repoTree(t)+	os.WriteFile(filepath.Join(dir, "index.md"), []byte("# Changed\n"), 0o644)+	if out, err := exec.Command("git", "-C", dir, "-c", "user.name=t", "-c", "user.email=t@x",+		"commit", "-qa", "--allow-empty-message", "-m", "").CombinedOutput(); err != nil {+		t.Fatalf("git commit: %v\n%s", err, out)+	}+	os.WriteFile(filepath.Join(dir, "index.md"), []byte("# Again\n"), 0o644)+	commitAll(t, dir, "One paragraph\nthat runs on")+	body := get(s.handler(), "/index.md?log").Body.String()+	empty, long := head(t, dir, "HEAD~1"), head(t, dir, "HEAD")+	for _, want := range []string{+		`<details data-diff="?commit=` + empty + `">`,+		`</span></span> <span class="subject"></span></summary>`,+		`<details data-diff="?commit=` + long + `">`,+		`</span></span> <span class="subject">One paragraph that runs on</span></summary>`,+	} {+		if !strings.Contains(body, want) {+			t.Errorf("no %q:\n%s", want, body)+		}+	}+}++// A directory without its slash keeps ?log through the redirect.+func TestHistoryRedirectKeepsQuery(t *testing.T) {+	s, _ := repoTree(t)+	if rec := get(s.handler(), "/a?log"); rec.Header().Get("Location") != "/a/?log" {+		t.Errorf("redirect to %q", rec.Header().Get("Location"))+	}+}++// Doc and code pages say at the top whether they match their last+// commit, which they name on hover; an edit since makes them changed.+func TestPageTopNamesLastCommit(t *testing.T) {+	s, dir := repoTree(t)+	h := s.handler()+	for p, subject := range map[string]string{"/index.md": "Add the docs", "/a/b.go": "Rename the package &lt;b&gt;"} {+		body := get(h, p).Body.String()+		if !strings.Contains(body, `<details class="own latest" data-timeline="?timeline">`) || !strings.Contains(body, ` · `+subject+` · `) || !strings.Contains(body, `">current</span></summary>`) ||+			!strings.Contains(body, `<div class="versions"><a href="?log">&lt;(git log)</a></div>`) || strings.Contains(body, `class="own now"`) {+			t.Errorf("%s: no top line with %q:\n%s", p, subject, body)+		}+	}+	if id := head(t, dir, "HEAD:a/b.go"); blobID([]byte("package b\n"), len(id)) != id {+		t.Errorf("blob id %s, git says %s", blobID([]byte("package b\n"), len(id)), id)+	}+	os.WriteFile(filepath.Join(dir, "a", "b.go"), []byte("package c\n"), 0o644)+	if body := get(h, "/a/b.go").Body.String(); !strings.Contains(body, `">changed</span></summary>`) {+		t.Errorf("edited page is not changed:\n%s", body)+	}+	if body := get(h, "/untracked/x.txt").Body.String(); strings.Contains(body, "?log") {+		t.Errorf("untracked file has a top line:\n%s", body)+	}+}++// Outside a repo nothing leads to history, and the page says why.+func TestNoRepoNoHistory(t *testing.T) {+	needGit(t)+	s, _, _ := serveTree(t)+	h := s.handler()+	if body := get(h, "/").Body.String(); strings.Contains(body, "?log") {+		t.Errorf("history entry outside a repo:\n%s", body)+	}+	if rec := get(h, "/?log"); rec.Code != http.StatusNotFound || !strings.Contains(rec.Body.String(), "not a git repository") {+		t.Errorf("status %d:\n%s", rec.Code, rec.Body.String())+	}+}++// A share shows history without trailers, and only while other users+// could read the repo. Its errors name no path.+func TestShareShowsHistory(t *testing.T) {+	needGit(t)+	s := shareTree(t)+	dir := s.list()[0].dir+	if s.list()[0].secret {+		dir = s.list()[1].dir+	}+	exec.Command("git", "init", "-q", dir).Run()+	commitAll(t, dir, "Shared subject\n\nThe body.\n\nClaude-Session: https://claude.ai/code/session_x\nSigned-off-by: t <t@x>")+	gitDir := filepath.Join(dir, ".git")+	exec.Command("chmod", "-R", "go+rX", gitDir).Run()+	h := s.handler()+	if body := get(h, "/docs/").Body.String(); !strings.Contains(body, `href="?log"`) {+		t.Errorf("share listing leads to no history:\n%s", body)+	}+	body := get(h, "/docs/?log").Body.String()+	if !strings.Contains(body, "Shared subject") || !strings.Contains(body, "<p>The body.</p>") {+		t.Errorf("share history:\n%s", body)+	}+	if strings.Contains(body, "claude.ai") || strings.Contains(body, "t@x") {+		t.Errorf("share history shows trailers:\n%s", body)+	}+	os.Chmod(filepath.Join(gitDir, "objects"), 0o700)+	if body := get(h, "/docs/").Body.String(); strings.Contains(body, "?log") {+		t.Errorf("history of a closed repo:\n%s", body)+	}+	rec := get(h, "/docs/?log")+	if rec.Code != http.StatusNotFound || !strings.Contains(rec.Body.String(), "No git history here.") || strings.Contains(rec.Body.String(), dir) {+		t.Errorf("closed repo: %d\n%s", rec.Code, rec.Body.String())+	}+}++// A commit page shows the message and the diff of the path it came from,+// and links to the commit across the tree.+func TestCommitPage(t *testing.T) {+	s, dir := repoTree(t)+	h := s.handler()+	c := head(t, dir, "HEAD")+	body := get(h, "/a/b.go?commit="+c).Body.String()+	for _, want := range []string{+		"Rename the package &lt;b&gt;",+		`</span> · <span class="hash">` + c + `</span></p>`,+		`<span class="del">-func F() {}</span><span class="add">+package b</span>`,+		`<a href="/?commit=` + c + `">All files</a>`,+		`<p class="own file"><a href="/a/b.go">a/b.go</a></p>`,+		`<a href="/a/b.go?log">&lt;(git log)</a>`,+		"</div>\n<div class=\"diffs\">\n<p class=\"own\">Changes to a/b.go.",+		"</pre>\n</div>\n",+	} {+		if !strings.Contains(body, want) {+			t.Errorf("no %q:\n%s", want, body)+		}+	}+	if body := get(h, "/index.md?commit="+c).Body.String(); !strings.Contains(body, "It does not change index.md.") {+		t.Errorf("commit that skips the file:\n%s", body)+	}+	first := get(h, "/?commit="+head(t, dir, "HEAD~1")).Body.String()+	if !strings.Contains(first, `<a href="/index.md">index.md</a>`) || !strings.Contains(first, `<a href="/a/b.go">a/b.go</a>`) || strings.Contains(first, "All files") {+		t.Errorf("whole commit:\n%s", first)+	}+	for _, bad := range []string{"zz", "-p", head(t, dir, "HEAD:a/b.go")} {+		if rec := get(h, "/?commit="+bad); rec.Code != http.StatusNotFound {+			t.Errorf("%s: status %d:\n%s", bad, rec.Code, rec.Body.String())+		}+	}+}++func TestDiffName(t *testing.T) {+	for in, want := range map[string]string{+		"a/x.md b/x.md":                     "x.md",+		"a/two words b/two words":           "two words",+		`"a/q\"uote" "b/q\"uote"`:           `q"uote`,+		`"a/tab\there.md" "b/tab\there.md"`: "tab\there.md",+	} {+		if got, ok := diffName(in); !ok || got != want {+			t.Errorf("%q: %q %v, want %q", in, got, ok, want)+		}+	}+}++// A share's diffs leave out dot files.+func TestShareDiffSkipsDots(t *testing.T) {+	needGit(t)+	s := shareTree(t)+	dir := s.list()[0].dir+	if s.list()[0].secret {+		dir = s.list()[1].dir+	}+	exec.Command("git", "init", "-q", dir).Run()+	os.WriteFile(filepath.Join(dir, ".env"), []byte("TOKEN=hidden\n"), 0o644)+	commitAll(t, dir, "Shared")+	exec.Command("chmod", "-R", "go+rX", filepath.Join(dir, ".git")).Run()+	body := get(s.handler(), "/docs/?commit="+head(t, dir, "HEAD")).Body.String()+	if !strings.Contains(body, "+docs/pub.txt") || strings.Contains(body, "hidden") {+		t.Errorf("share diff:\n%s", body)+	}+}++// A history that git was slow to give names the command that writes+// changed-path filters, until the repo has them. A share never names it.+func TestSlowHistoryNamesCommitGraph(t *testing.T) {+	s, dir := repoTree(t)+	h := s.handler()+	defer func(d time.Duration) { slowGit = d }(slowGit)+	slowGit = -1+	hint := "git commit-graph write --reachable --changed-paths"+	if body := get(h, "/?log").Body.String(); !strings.Contains(body, hint) {+		t.Errorf("no hint without filters:\n%s", body)+	}+	if out, err := exec.Command("git", "-C", dir, "commit-graph", "write", "--reachable", "--changed-paths").CombinedOutput(); err != nil {+		t.Fatalf("commit-graph: %v\n%s", err, out)+	}+	if body := get(h, "/index.md?log").Body.String(); strings.Contains(body, hint) {+		t.Errorf("hint with filters:\n%s", body)+	}+	os.Remove(filepath.Join(dir, ".git", "objects", "info", "commit-graph"))+	if out, err := exec.Command("git", "-C", dir, "commit-graph", "write", "--reachable", "--split").CombinedOutput(); err != nil {+		t.Fatalf("commit-graph: %v\n%s", err, out)+	}+	if body := get(h, "/a/?log").Body.String(); !strings.Contains(body, hint) {+		t.Errorf("no hint for a split graph without filters:\n%s", body)+	}+	if out, err := exec.Command("git", "-C", dir, "commit-graph", "write", "--reachable", "--split=replace", "--changed-paths").CombinedOutput(); err != nil {+		t.Fatalf("commit-graph: %v\n%s", err, out)+	}+	if body := get(h, "/a/b.go?log").Body.String(); strings.Contains(body, hint) {+		t.Errorf("hint for a split graph with filters:\n%s", body)+	}+}

live_test.go

@@ -302,3 +302,17 @@ func TestPagesRecord(t *testing.T) { 		t.Errorf("record %q", b) 	} }++// A commit reloads an open history page.+func TestLiveReloadsOnCommit(t *testing.T) {+	needGit(t)+	s, _, dir, ts := liveTree(t)+	exec.Command("git", "init", "-q", dir).Run()+	commitAll(t, dir, "First")+	lines := stream(t, s, ts, "/a/")+	time.Sleep(50 * time.Millisecond)+	exec.Command("git", "-C", dir, "-c", "user.name=t", "-c", "user.email=t@x", "commit", "-q", "--allow-empty", "-m", "Second").Run()+	if !reloads(lines, 2*time.Second) {+		t.Fatal("no reload after a commit")+	}+}