Method Colorize

pkg/callstack/colorize.go:47–140

Colorize renders a callstack as a multi-line, ANSI-colourised string. It works directly with the typed Frame slice so no string parsing is required. Visual hierarchy per frame (left > right, dim > bright): ! Frame tiers ──────

()

// Consecutive unresolved frames (kernel-space with no symbol) are collapsed
// into a single dim counter line to avoid flooding the view.
func (s Callstack) Colorize() string {
	if s.IsEmpty() {
		return ""
	}

	// iterate in reverse so the outermost frame comes first
	depth := s.Depth()
	l := s.maxAddrLength()

	var idx int
	var unresolved int
	var b strings.Builder
	b.Grow(depth * 100)

	flushUnresolved := func() {
		if unresolved == 0 {
			return
		}
		line := fmt.Sprintf("  %s %d unresolved %s",
			colorizer.SpanDim("▸"),
			unresolved,
			"frame(s)",
		)
		b.WriteString(colorizer.SpanDim(colorizer.Span(colorizer.Gray, line)))
		b.WriteByte('\n')
		unresolved = 0
	}

	for i := depth - 1; i >= 0; i-- {
		f := s.FrameAt(i)

		// frames in kernel range with no resolved symbol are unresolved so
		// we can collapse them into a counter
		if f.Addr.InSystemRange() && (f.Symbol == "" || f.Symbol == "?") {
			unresolved++
			continue
		}

		flushUnresolved()
		idx++

		// draw gutter
		b.WriteString(colorizer.SpanDim(colorizer.Span(colorizer.Gray, fmt.Sprintf("  %3d  ", idx))))

		// draw address
		addrStr := "0x" + f.Addr.String()
		paddedAddr := addrStr + strings.Repeat(" ", l-len(addrStr))
		b.WriteString(colorizer.SpanDim(colorizer.Span(colorizer.Gray, paddedAddr)))
		b.WriteString("  ")

		// unbacked means execution from anonymous memory which is the highest-
		// suspicion tier, rendered red regardless of address range.
		if f.IsUnbacked() {
			b.WriteString(f.colorizeUnbacked())
			b.WriteByte('\n')
			continue
		}