mirror of https://github.com/garrytan/gstack.git
620 lines
23 KiB
TypeScript
620 lines
23 KiB
TypeScript
/**
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* Diagram + image pre-pass. Runs between "read markdown" and render() in the
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* orchestrator, and owns everything that needs the diagram-render bundle.
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*
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* markdown ─▶ extractDiagramFences() ──▶ render() (marked+sanitize+smarty)
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* │ fences → placeholder tokens │
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* │ ▼
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* └─▶ renderFenceSlots() ───────────▶ substituteSlots(html, slots)
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* one browse render tab/run │
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* error ⇒ diagnostic block + page reload ▼
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* inlineLocalImages(html)
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* data URIs, probe dims from bytes,
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* downscale >2x content box @300dpi,
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* remote warn / missing placeholder /
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* --strict hard-fail
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*
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* Placeholders survive marked, the sanitizer, and smartypants because they are
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* plain hyphenated lowercase tokens with no quotes or HTML. Slot HTML is run
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* through the same sanitizer as user content before substitution (the bundle
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* renders with securityLevel strict — the sanitizer is the second layer).
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*
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* Reset contract (eng-review D6.2): each fence renders with a fresh
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* mermaid.render id; after ANY render error the bundle page is reloaded before
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* the next fence so a poisoned global can't corrupt diagram N+1.
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*/
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import * as fs from "node:fs";
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import * as os from "node:os";
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import * as path from "node:path";
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import * as crypto from "node:crypto";
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import * as browseClient from "./browseClient";
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import { sanitizeUntrustedHtml } from "./render";
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import { imageDims } from "./image-size";
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// ─── Types ────────────────────────────────────────────────────────────
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export interface DiagramFence {
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/** "mermaid" | "excalidraw" */
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lang: string;
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/** Fence body (the diagram source). */
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source: string;
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/** Optional title="..." from the fence info string (a11y label, D6.4). */
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title?: string;
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/** Optional page=landscape|portrait fence directive (image-policy override). */
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page?: "landscape" | "portrait";
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/** render=false → leave as a plain code block (escape hatch, D6.3). */
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render: boolean;
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/** Placeholder token substituted into the markdown. */
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token: string;
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/** 1-based ordinal among rendered fences (unique ids, aria fallback). */
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ordinal: number;
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}
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export interface FenceExtraction {
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markdown: string;
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fences: DiagramFence[];
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}
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export interface PrepassWarnings {
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warn: (msg: string) => void;
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}
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export interface PrepassImageOptions {
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/** Directory of the source markdown — relative image paths resolve here. */
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inputDir: string;
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/** Hard-fail on missing/remote images instead of warn (D6.1). */
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strict: boolean;
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/** Remote images are left untouched when network is explicitly allowed. */
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allowNetwork: boolean;
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/** Physical content-box width in inches (page width minus margins). */
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contentWidthIn: number;
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warn: (msg: string) => void;
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/** Lazily provides a ready bundle tab (only opened when needed). */
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getTab: () => RenderTab | null;
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}
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/** Print-resolution policy (eng-review D4): downscale rasters wider than
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* 2 × contentWidth × 300dpi down to contentWidth × 300dpi. */
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const PRINT_DPI = 300;
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const DOWNSCALE_FACTOR = 2;
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export class StrictModeError extends Error {
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constructor(msg: string) {
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super(msg);
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this.name = "StrictModeError";
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}
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}
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// ─── Fence extraction (pure) ──────────────────────────────────────────
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const DIAGRAM_LANGS = new Set(["mermaid", "excalidraw"]);
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/**
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* Extract top-level ```mermaid / ```excalidraw fences, replacing each with a
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* unique placeholder token paragraph. Backtick and tilde fences, any length
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* >= 3; closers must be at least as long as the opener (CommonMark). Fences
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* with `render=false` in the info string are left untouched.
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*/
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export function extractDiagramFences(markdown: string): FenceExtraction {
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const lines = markdown.split("\n");
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const out: string[] = [];
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const fences: DiagramFence[] = [];
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const runId = crypto.randomBytes(4).toString("hex");
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let i = 0;
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let openFence: { char: string; len: number; info: string; body: string[] } | null = null;
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let ordinal = 0;
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while (i < lines.length) {
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const line = lines[i];
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if (openFence) {
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const close = matchFenceLine(line);
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if (close && close.char === openFence.char && close.len >= openFence.len && close.info === "") {
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const info = parseInfoString(openFence.info);
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if (DIAGRAM_LANGS.has(info.lang) && info.render) {
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ordinal++;
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const token = `gstack-diagram-slot-${runId}-${ordinal}`;
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fences.push({
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lang: info.lang,
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source: openFence.body.join("\n"),
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title: info.title,
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page: info.page,
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render: true,
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token,
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ordinal,
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});
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out.push("", token, "");
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} else {
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// Not a diagram fence (or render=false): replay verbatim, but strip
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// the render=false flag so it never leaks into highlighted output.
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const infoOut = info.render ? openFence.info : info.lang;
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out.push(`${openFence.char.repeat(openFence.len)}${infoOut}`);
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out.push(...openFence.body);
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out.push(line);
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}
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openFence = null;
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i++;
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continue;
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}
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openFence.body.push(line);
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i++;
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continue;
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}
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const open = matchFenceLine(line);
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if (open && open.info !== "") {
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openFence = { char: open.char, len: open.len, info: open.info, body: [] };
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i++;
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continue;
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}
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if (open) {
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// Anonymous fence (plain code block) — copy through to its closer so a
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// ```mermaid example INSIDE a plain fence is never extracted.
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out.push(line);
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i++;
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while (i < lines.length) {
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const l = lines[i];
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const close = matchFenceLine(l);
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out.push(l);
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i++;
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if (close && close.char === open.char && close.len >= open.len && close.info === "") break;
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}
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continue;
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}
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out.push(line);
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i++;
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}
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// Unclosed fence at EOF: replay verbatim (CommonMark treats it as code to EOF).
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if (openFence) {
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out.push(`${openFence.char.repeat(openFence.len)}${openFence.info}`);
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out.push(...openFence.body);
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}
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return { markdown: out.join("\n"), fences };
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}
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function matchFenceLine(line: string): { char: string; len: number; info: string } | null {
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const m = line.match(/^ {0,3}(`{3,}|~{3,})\s*(.*)$/);
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if (!m) return null;
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return { char: m[1][0], len: m[1].length, info: m[2].trim() };
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}
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/** Parse a fence info string: `mermaid`, `mermaid render=false`,
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* `mermaid title="Auth flow"`, `mermaid page=landscape`. */
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export function parseInfoString(info: string): {
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lang: string; render: boolean; title?: string; page?: "landscape" | "portrait";
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} {
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const lang = (info.match(/^\S+/)?.[0] ?? "").toLowerCase();
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const render = !/\brender\s*=\s*false\b/i.test(info);
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const title = info.match(/\btitle\s*=\s*"([^"]*)"/i)?.[1]
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?? info.match(/\btitle\s*=\s*'([^']*)'/i)?.[1];
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const pageRaw = info.match(/\bpage\s*=\s*(landscape|portrait)\b/i)?.[1]?.toLowerCase();
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const page = pageRaw === "landscape" || pageRaw === "portrait" ? pageRaw : undefined;
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return { lang, render, title, page };
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}
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// ─── Slot substitution (pure) ─────────────────────────────────────────
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/**
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* Replace placeholder tokens in rendered HTML with their final slot HTML.
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* marked wraps the bare token line in <p>…</p>; replace the wrapper too so
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* the figure isn't nested inside a paragraph.
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*/
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export function substituteSlots(html: string, slots: Map<string, string>): string {
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let s = html;
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for (const [token, slotHtml] of slots) {
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const wrapped = new RegExp(`<p>\\s*${token}\\s*</p>`, "g");
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if (wrapped.test(s)) {
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s = s.replace(new RegExp(`<p>\\s*${token}\\s*</p>`, "g"), slotHtml);
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} else {
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s = s.split(token).join(slotHtml);
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}
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}
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return s;
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}
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/**
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* Visible diagnostic block for a failed fence render — never silent raw code
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* (eng-review: explicit error blocks). Sanitizer-safe: all dynamic content is
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* HTML-escaped.
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*/
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export function buildDiagnosticBlock(fence: DiagramFence, errorMessage: string): string {
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const excerpt = fence.source.split("\n").slice(0, 8).join("\n");
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const truncated = fence.source.split("\n").length > 8 ? "\n…" : "";
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return [
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`<figure class="diagram diagram-error" role="img" aria-label="${escapeAttr(diagramLabel(fence))} (failed to render)">`,
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`<figcaption class="diagram-error-title">Diagram failed to render (${escapeHtml(fence.lang)})</figcaption>`,
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`<pre class="diagram-error-detail">${escapeHtml(errorMessage.trim())}\n\n${escapeHtml(excerpt + truncated)}</pre>`,
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`</figure>`,
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].join("\n");
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}
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/** Wrap a rendered SVG in an accessible figure (D6.4). */
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export function buildDiagramFigure(fence: DiagramFence, svg: string): string {
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const label = diagramLabel(fence);
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const cleanSvg = sanitizeUntrustedHtml(svg);
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const captioned = fence.title
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? `\n<figcaption class="diagram-caption">${escapeHtml(fence.title)}</figcaption>`
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: "";
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const pageAttr = fence.page ? ` data-gstack-page="${fence.page}"` : "";
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return [
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`<figure class="diagram" role="img" aria-label="${escapeAttr(label)}"${pageAttr}>`,
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`<!-- gstack-diagram-source lang=${escapeAttr(fence.lang)}`,
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escapeHtmlComment(fence.source),
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`-->`,
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cleanSvg,
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captioned,
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`</figure>`,
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].join("\n");
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}
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function diagramLabel(fence: DiagramFence): string {
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return fence.title ?? `diagram ${fence.ordinal}`;
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}
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// ─── Render tab (bundle page lifecycle) ───────────────────────────────
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const PAYLOAD_TMP_DIR = process.platform === "win32" ? os.tmpdir() : "/tmp";
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const READY_TIMEOUT_MS = 20_000;
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export class RenderTab {
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private constructor(
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public readonly tabId: number,
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private readonly stagedBundlePath: string,
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) {}
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/**
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* Open a tab and load the diagram-render bundle. The bundle HTML is staged
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* under /tmp (content-addressed, reused across runs — load-html only reads
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* inside its safe dirs) and loaded by PATH, not --from-file: a 9MB JSON
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* round-trip per run would be pure waste.
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*/
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static open(): RenderTab {
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const bundleSrc = resolveBundlePath();
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const html = fs.readFileSync(bundleSrc);
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const sha = crypto.createHash("sha256").update(html).digest("hex").slice(0, 16);
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const staged = path.join(PAYLOAD_TMP_DIR, `gstack-diagram-render-${sha}.html`);
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if (!fs.existsSync(staged)) {
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// Concurrent-safe: write to a unique temp name, then atomic rename.
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const tmp = `${staged}.${process.pid}.${crypto.randomBytes(4).toString("hex")}`;
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fs.writeFileSync(tmp, html);
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try {
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fs.renameSync(tmp, staged);
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} catch {
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fs.unlinkSync(tmp); // another process won the race — theirs is identical
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}
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}
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const tabId = browseClient.newtab();
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const tab = new RenderTab(tabId, staged);
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tab.loadBundle();
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return tab;
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}
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/** (Re)load the bundle page — also the reset path after a render error. */
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loadBundle(): void {
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browseClient.loadHtmlFile({ file: this.stagedBundlePath, tabId: this.tabId });
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const ready = browseClient.waitForExpression({
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expression: "document.getElementById('status') !== null && document.getElementById('status').textContent === 'ready'",
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tabId: this.tabId,
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timeoutMs: READY_TIMEOUT_MS,
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});
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if (!ready) {
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throw new Error(
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"diagram-render bundle did not become ready in the browse tab " +
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`(${READY_TIMEOUT_MS}ms). Check \`browse js "window.__errors"\` on tab ${this.tabId}.`,
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);
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}
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}
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/**
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* Call one of the bundle's async window functions with JSON-safe string
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* args. Errors come back as a recognizable ERR: prefix so a render failure
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* is data, not a thrown browse exit.
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*/
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call(fn: string, ...args: Array<string | number>): string {
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const argList = args.map((a) => JSON.stringify(a)).join(",");
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const expression =
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`window.${fn}(${argList})` +
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`.then(r => "OK:" + r)` +
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`.catch(e => "ERR:" + String((e && e.message) || e))`;
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const result = this.js(expression);
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if (result.startsWith("OK:")) return result.slice(3);
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if (result.startsWith("ERR:")) throw new RenderCallError(result.slice(4));
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throw new RenderCallError(`unexpected bundle result: ${result.slice(0, 200)}`);
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}
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private js(expression: string): string {
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// Large payloads (scene JSON, SVG text, data URIs) blow past argv limits —
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// browseClient.js shells out with the expression as an argv element, so
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// stage anything big through a tmp file the page can fetch? No: file URLs
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// are unreachable from the page. Instead, chunk through a window buffer.
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if (expression.length <= 100_000) {
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return browseClient.js({ expression, tabId: this.tabId });
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}
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return this.jsViaBuffer(expression);
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}
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/**
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* argv-safe path for big expressions: ship the expression into the page in
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* 64KB chunks (window.__exprBuf), then eval it there. Used for multi-MB
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* data URIs (photo downscaling) where a single argv would exceed OS limits.
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*/
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private jsViaBuffer(expression: string): string {
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browseClient.js({ expression: "window.__exprBuf = ''", tabId: this.tabId });
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const CHUNK = 64_000;
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for (let i = 0; i < expression.length; i += CHUNK) {
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const chunk = expression.slice(i, i + CHUNK);
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browseClient.js({
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expression: `window.__exprBuf += ${JSON.stringify(chunk)}, window.__exprBuf.length`,
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tabId: this.tabId,
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});
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}
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// Eval the buffer as a single expression so the resulting promise is the
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// statement value browse awaits. The buffer resets at the next call.
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return browseClient.js({
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expression: `(0, eval)(window.__exprBuf)`,
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tabId: this.tabId,
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});
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}
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close(): void {
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try {
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browseClient.closetab(this.tabId);
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} catch {
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// best-effort: orchestrator finally path
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}
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}
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}
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export class RenderCallError extends Error {
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constructor(msg: string) {
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super(msg);
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this.name = "RenderCallError";
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}
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}
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/** Resolve dist/diagram-render.html: env override → repo-relative (dev) → global install. */
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export function resolveBundlePath(env: NodeJS.ProcessEnv = process.env): string {
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const candidates = [
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env.GSTACK_DIAGRAM_BUNDLE,
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// dev: make-pdf/src/* → repo root lib/. (In a compiled binary this is the
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// virtual /$bunfs/root and simply never exists — harmless.)
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path.resolve(import.meta.dir, "../../lib/diagram-render/dist/diagram-render.html"),
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// compiled binary at <root>/make-pdf/dist/pdf → <root>/lib/… — same shape
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// in the repo and in the ~/.claude/skills/gstack global install. argv[0]
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// is the literal string "bun" in compiled binaries; execPath is real.
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path.resolve(path.dirname(process.execPath), "../../lib/diagram-render/dist/diagram-render.html"),
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path.join(os.homedir(), ".claude/skills/gstack/lib/diagram-render/dist/diagram-render.html"),
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].filter((p): p is string => !!p);
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for (const p of candidates) {
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if (fs.existsSync(p)) return p;
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}
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throw new Error(
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"diagram-render bundle not found. Tried:\n" +
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candidates.map((c) => ` - ${c}`).join("\n") +
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"\nRun `bun run build:diagram-render` (repo) or re-run ./setup (install).",
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);
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}
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// ─── Fence rendering ──────────────────────────────────────────────────
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/**
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* Render every extracted fence to its slot HTML. One bundle tab serves all
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* fences; a failed fence yields a diagnostic block and a bundle reload
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* (reset contract) before the next fence renders.
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*/
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export function renderFenceSlots(
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fences: DiagramFence[],
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tab: RenderTab,
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warn: (msg: string) => void,
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): Map<string, string> {
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const slots = new Map<string, string>();
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for (const fence of fences) {
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try {
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let svg: string;
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if (fence.lang === "mermaid") {
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svg = tab.call("__renderMermaid", `mermaid-fence-${fence.ordinal}`, fence.source);
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} else {
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JSON.parse(fence.source); // fail fast with a JSON diagnostic, not a bundle stack
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svg = tab.call("__excalidrawToSvg", fence.source);
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}
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slots.set(fence.token, buildDiagramFigure(fence, svg));
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} catch (err: any) {
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const msg = err?.message ?? String(err);
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warn(`diagram ${fence.ordinal} (${fence.lang}) failed to render: ${firstLine(msg)}`);
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slots.set(fence.token, buildDiagnosticBlock(fence, msg));
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// Reset contract: a poisoned page must not corrupt the next fence.
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try {
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tab.loadBundle();
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} catch (reloadErr: any) {
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warn(`bundle reload after render error failed: ${firstLine(reloadErr?.message ?? String(reloadErr))}`);
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}
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}
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}
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return slots;
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}
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// ─── Image inlining (eng-review D1 + D4 + D6.1) ───────────────────────
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const IMG_TAG_RE = /<img\b[^>]*>/gi;
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const SRC_RE = /\bsrc\s*=\s*("([^"]*)"|'([^']*)')/i;
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/**
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* Inline every local <img> as a data URI, probe intrinsic dimensions from the
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* bytes, and annotate the tag with data-gstack-px-width/-height for the width
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* policy. Oversized rasters are downscaled to print resolution via the bundle
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* tab. Missing files become visible placeholders (or throw under --strict);
|
||
* remote URLs warn (offline posture) unless --allow-network.
|
||
*/
|
||
export function inlineLocalImages(html: string, opts: PrepassImageOptions): string {
|
||
const maxPx = Math.round(opts.contentWidthIn * PRINT_DPI * DOWNSCALE_FACTOR);
|
||
const targetPx = Math.round(opts.contentWidthIn * PRINT_DPI);
|
||
|
||
return html.replace(IMG_TAG_RE, (tag) => {
|
||
const srcMatch = tag.match(SRC_RE);
|
||
if (!srcMatch) return tag;
|
||
const src = srcMatch[2] ?? srcMatch[3] ?? "";
|
||
|
||
if (src.startsWith("data:")) return annotateFromDataUri(tag, src);
|
||
|
||
if (/^[a-z][a-z0-9+.-]*:/i.test(src)) {
|
||
// Absolute URL with a scheme (http, https, file, …)
|
||
if (opts.allowNetwork && /^https?:/i.test(src)) return tag;
|
||
if (/^https?:/i.test(src)) {
|
||
const msg = `remote image not fetched (offline posture): ${src}`;
|
||
if (opts.strict) throw new StrictModeError(msg + " — re-run without --strict or pass --allow-network");
|
||
opts.warn(msg);
|
||
return tag;
|
||
}
|
||
// file:// and friends fall through to the local path branch
|
||
if (!src.startsWith("file:")) return tag;
|
||
}
|
||
|
||
const filePath = src.startsWith("file:")
|
||
? decodeURIComponent(new URL(src).pathname)
|
||
: path.resolve(opts.inputDir, decodeURIComponent(src));
|
||
|
||
if (!fs.existsSync(filePath)) {
|
||
const msg = `image not found: ${src} (resolved to ${filePath})`;
|
||
if (opts.strict) throw new StrictModeError(msg);
|
||
opts.warn(msg);
|
||
return buildMissingImagePlaceholder(src);
|
||
}
|
||
|
||
let buf = fs.readFileSync(filePath);
|
||
let dims = imageDims(buf);
|
||
let mime = dims?.mime ?? mimeFromExtension(filePath);
|
||
|
||
// Print-resolution normalization (D4): rasters only — SVG scales free.
|
||
if (dims && mime !== "image/svg+xml" && dims.width > maxPx) {
|
||
const tab = opts.getTab();
|
||
if (tab) {
|
||
try {
|
||
const dataUri = `data:${mime};base64,${buf.toString("base64")}`;
|
||
const scaled = tab.call("__downscaleRaster", dataUri, targetPx, mime);
|
||
const scaledB64 = scaled.replace(/^data:[^,]*,/, "");
|
||
opts.warn(
|
||
`downscaled ${path.basename(filePath)} ${dims.width}px → ${targetPx}px ` +
|
||
`(print is ${PRINT_DPI}dpi; original exceeds ${maxPx}px content-box ceiling)`,
|
||
);
|
||
buf = Buffer.from(scaledB64, "base64");
|
||
mime = scaled.slice(5, scaled.indexOf(";"));
|
||
dims = { ...dims, height: Math.round((dims.height * targetPx) / dims.width), width: targetPx };
|
||
} catch (err: any) {
|
||
opts.warn(`downscale failed for ${src}, inlining at full size: ${firstLine(err?.message ?? String(err))}`);
|
||
}
|
||
}
|
||
}
|
||
|
||
const dataUri = `data:${mime};base64,${buf.toString("base64")}`;
|
||
let newTag = tag.replace(SRC_RE, `src="${dataUri}"`);
|
||
if (dims) {
|
||
newTag = newTag.replace(
|
||
/^<img\b/i,
|
||
`<img data-gstack-px-width="${Math.round(dims.width)}" data-gstack-px-height="${Math.round(dims.height)}"`,
|
||
);
|
||
}
|
||
return newTag;
|
||
});
|
||
}
|
||
|
||
function annotateFromDataUri(tag: string, src: string): string {
|
||
try {
|
||
const b64 = src.slice(src.indexOf(",") + 1);
|
||
const head = Buffer.from(b64.slice(0, 8192), "base64");
|
||
const dims = imageDims(head);
|
||
if (!dims) return tag;
|
||
return tag.replace(
|
||
/^<img\b/i,
|
||
`<img data-gstack-px-width="${Math.round(dims.width)}" data-gstack-px-height="${Math.round(dims.height)}"`,
|
||
);
|
||
} catch {
|
||
return tag;
|
||
}
|
||
}
|
||
|
||
function buildMissingImagePlaceholder(src: string): string {
|
||
return (
|
||
`<span class="image-missing" role="img" aria-label="missing image">` +
|
||
`[missing image: ${escapeHtml(src)}]</span>`
|
||
);
|
||
}
|
||
|
||
function mimeFromExtension(p: string): string {
|
||
switch (path.extname(p).toLowerCase()) {
|
||
case ".png": return "image/png";
|
||
case ".jpg":
|
||
case ".jpeg": return "image/jpeg";
|
||
case ".gif": return "image/gif";
|
||
case ".webp": return "image/webp";
|
||
case ".svg": return "image/svg+xml";
|
||
default: return "application/octet-stream";
|
||
}
|
||
}
|
||
|
||
// ─── Content-box math ─────────────────────────────────────────────────
|
||
|
||
const PAGE_WIDTHS_IN: Record<string, number> = {
|
||
letter: 8.5,
|
||
a4: 8.27,
|
||
legal: 8.5,
|
||
tabloid: 11,
|
||
};
|
||
|
||
/** Parse a CSS dimension ("1in" | "72pt" | "25mm" | "2.54cm") to inches. */
|
||
export function dimToInches(dim: string | undefined, fallbackIn: number): number {
|
||
if (!dim) return fallbackIn;
|
||
const m = dim.trim().match(/^([0-9.]+)\s*(in|pt|cm|mm|px)?$/i);
|
||
if (!m) return fallbackIn;
|
||
const v = parseFloat(m[1]);
|
||
switch ((m[2] ?? "in").toLowerCase()) {
|
||
case "in": return v;
|
||
case "pt": return v / 72;
|
||
case "cm": return v / 2.54;
|
||
case "mm": return v / 25.4;
|
||
case "px": return v / 96;
|
||
default: return fallbackIn;
|
||
}
|
||
}
|
||
|
||
export function contentWidthInches(opts: {
|
||
pageSize?: string;
|
||
margins?: string;
|
||
marginLeft?: string;
|
||
marginRight?: string;
|
||
}): number {
|
||
const pageW = PAGE_WIDTHS_IN[opts.pageSize ?? "letter"] ?? 8.5;
|
||
const left = dimToInches(opts.marginLeft ?? opts.margins, 1);
|
||
const right = dimToInches(opts.marginRight ?? opts.margins, 1);
|
||
return Math.max(1, pageW - left - right);
|
||
}
|
||
|
||
// ─── tiny helpers ─────────────────────────────────────────────────────
|
||
|
||
function escapeHtml(s: string): string {
|
||
return s
|
||
.replace(/&/g, "&")
|
||
.replace(/</g, "<")
|
||
.replace(/>/g, ">")
|
||
.replace(/"/g, """)
|
||
.replace(/'/g, "'");
|
||
}
|
||
|
||
function escapeAttr(s: string): string {
|
||
return escapeHtml(s);
|
||
}
|
||
|
||
/** Comments may not contain `--`; encode it so the raw source survives. */
|
||
function escapeHtmlComment(s: string): string {
|
||
return s.replace(/--/g, "-‐");
|
||
}
|
||
|
||
function firstLine(s: string): string {
|
||
return s.split("\n")[0].slice(0, 200);
|
||
}
|