Add search to pager (e196f8d7) · Commits · Personal Projects / bulletin

pager/pager.go

+107 −1

Original line number	Diff line number	Diff line
		@@ -16,6 +16,60 @@ import (
		"golang.org/x/term"
		)

		// readLine reads a line of input in raw mode, echoing characters.
		// Returns the entered string, or "" if ESC is pressed or input is empty.
		func readLine(prompt string) string {
		fmt.Print(prompt)
		var buf []byte
		for {
		key, err := readKey()
		if err != nil {
		return ""
		}
		switch key {
		case 0x1b: // ESC
		return ""
		case '\r', '\n':
		return string(buf)
		case 0x7f, 0x08: // backspace
		if len(buf) > 0 {
		buf = buf[:len(buf)-1]
		fmt.Print("\b \b")
		}
		default:
		if key >= 0x20 {
		buf = append(buf, key)
		fmt.Printf("%c", key)
		}
		}
		}
		}

		// highlightLine returns the line with all case-insensitive occurrences of term
		// wrapped in ANSI reverse video.
		func highlightLine(line, searchTerm string) string {
		if searchTerm == "" {
		return line
		}
		lower := strings.ToLower(line)
		lowerTerm := strings.ToLower(searchTerm)
		var b strings.Builder
		i := 0
		for i < len(lower) {
		idx := strings.Index(lower[i:], lowerTerm)
		if idx < 0 {
		b.WriteString(line[i:])
		break
		}
		b.WriteString(line[i : i+idx])
		b.WriteString("\033[7m")
		b.WriteString(line[i+idx : i+idx+len(searchTerm)])
		b.WriteString("\033[0m")
		i += idx + len(searchTerm)
		}
		return b.String()
		}

		func getTerminalHeight() (int, error) {
		ws, err := unix.IoctlGetWinsize(0, unix.TIOCGWINSZ)
		if err != nil {
		@@ -34,6 +88,30 @@ func readKey() (byte, error) {
		return buf[0], nil
		}

		// searchForward finds the next line containing term (case-insensitive),
		// starting from the given line index. Returns -1 if not found.
		func searchForward(lines []string, term string, from int) int {
		lower := strings.ToLower(term)
		for i := max(from, 0); i < len(lines); i++ {
		if strings.Contains(strings.ToLower(lines[i]), lower) {
		return i
		}
		}
		return -1
		}

		// searchBackward finds the previous line containing term (case-insensitive),
		// searching backward from the given line index. Returns -1 if not found.
		func searchBackward(lines []string, term string, from int) int {
		lower := strings.ToLower(term)
		for i := min(from, len(lines)-1); i >= 0; i-- {
		if strings.Contains(strings.ToLower(lines[i]), lower) {
		return i
		}
		}
		return -1
		}

		// SanitizeText removes terminal escape sequences and dangerous control
		// characters from text, while preserving UTF-8 and normal whitespace.
		func SanitizeText(s string) string {
		@@ -76,6 +154,7 @@ func Pager(content string) bool {
		defer term.Restore(fd, oldState) // #nosec G115

		start := 0
		searchTerm := ""
		for {
		// State for where we are.
		if start < 0 {
		@@ -85,7 +164,11 @@ func Pager(content string) bool {

		// Clear prompt and display the chunk.
		fmt.Print("\r \r")
		fmt.Print(strings.Join(lines[start:end], "\r\n"))
		visible := make([]string, end-start)
		for i, line := range lines[start:end] {
		visible[i] = highlightLine(line, searchTerm)
		}
		fmt.Print(strings.Join(visible, "\r\n"))

		if end == totalLines {
		fmt.Println("\r") // move to next line after paging ends
		@@ -110,6 +193,29 @@ func Pager(content string) bool {
		case 'q', 'Q': // quit
		fmt.Println("\r") // move cursor to next line
		return false
		case '/': // search
		fmt.Print("\r \r")
		t := readLine("/")
		if t != "" {
		searchTerm = t
		if pos := searchForward(lines, searchTerm, start); pos >= 0 {
		start = pos
		} else {
		fmt.Print("\r\nNot found")
		}
		}
		case 'n': // next match
		if searchTerm != "" {
		if pos := searchForward(lines, searchTerm, start+1); pos >= 0 {
		start = pos
		}
		}
		case 'N': // previous match
		if searchTerm != "" {
		if pos := searchBackward(lines, searchTerm, start-1); pos >= 0 {
		start = pos
		}
		}
		}
		}
		}