From 8c59bc7fb0859fcb183789787f99a87f267f0bbe Mon Sep 17 00:00:00 2001 From: Paul Bakaus Date: Mon, 31 Aug 2026 19:34:07 -0400 Subject: [PATCH] Centralize image prompt parsing (#641) Centralize raster prompt lookup and PNG chunk parsing while preserving read, scan, replacement, and sidecar behavior. AI-assisted merge: reviewed and executed by Codex under explicit interactive maintainer direction. --- skill/scripts/embed-prompt.mjs | 103 +++++++++++++++------------------ tests/new-work-e2e.test.mjs | 56 ++++++++++++++++++ 2 files changed, 103 insertions(+), 56 deletions(-) diff --git a/skill/scripts/embed-prompt.mjs b/skill/scripts/embed-prompt.mjs index a5e7614c2..f2cb570ad 100644 --- a/skill/scripts/embed-prompt.mjs +++ b/skill/scripts/embed-prompt.mjs @@ -21,22 +21,24 @@ import zlib from 'node:zlib'; const KEYWORD = 'impeccable:prompt'; const args = process.argv.slice(2); const file = args.find(a => !a.startsWith('--')); -const readMode = args.includes('--read'); -const scanMode = args.includes('--scan'); const argOf = (name) => { const i = args.indexOf(name); return i !== -1 ? args[i + 1] : null; }; -function promptOf(imagePath) { - const b = fs.readFileSync(imagePath); - let prompt = null; - if (b.length > 8 && b.readUInt32BE(0) === 0x89504e47) prompt = readPngText(b); - else if (b.length > 3 && b[0] === 0xff && b[1] === 0xd8) prompt = readJpegCom(b); +function imageType(buffer) { + if (buffer.length > 8 && buffer.readUInt32BE(0) === 0x89504e47) return 'png'; + if (buffer.length > 3 && buffer[0] === 0xff && buffer[1] === 0xd8) return 'jpeg'; + return null; +} + +function readPrompt(imagePath, buffer = fs.readFileSync(imagePath)) { + const type = imageType(buffer); + let prompt = type === 'png' ? parsePng(buffer).prompt : type === 'jpeg' ? readJpegCom(buffer) : null; if (prompt == null && fs.existsSync(`${imagePath}.json`)) { try { prompt = JSON.parse(fs.readFileSync(`${imagePath}.json`, 'utf8')).prompt ?? null; } catch { /* stays null */ } } return prompt; } -if (scanMode) { +if (args.includes('--scan')) { const targets = args.filter(a => !a.startsWith('--')); if (targets.length === 0) { console.error('embed-prompt: --scan needs at least one directory'); process.exit(1); } const RASTER = /\.(png|jpe?g|webp)$/i; @@ -59,7 +61,7 @@ if (scanMode) { } let missing = 0; for (const raster of rasters) { - if (promptOf(raster) == null) { console.log(`MISSING: ${raster}`); missing++; } + if (readPrompt(raster) == null) { console.log(`MISSING: ${raster}`); missing++; } } console.log(`SCAN: ${rasters.length} raster${rasters.length === 1 ? '' : 's'}, ${missing} missing`); process.exit(missing > 0 ? 3 : 0); @@ -68,8 +70,7 @@ if (scanMode) { if (!file || !fs.existsSync(file)) { console.error('embed-prompt: image file required'); process.exit(1); } const buf = fs.readFileSync(file); -const isPng = buf.length > 8 && buf.readUInt32BE(0) === 0x89504e47; -const isJpeg = buf.length > 3 && buf[0] === 0xff && buf[1] === 0xd8; +const type = imageType(buf); const crcTable = (() => { const t = new Uint32Array(256); @@ -87,22 +88,26 @@ function pngChunk(type, data) { return out; } -function readPngText(b) { - let off = 8; - while (off + 12 <= b.length) { - const len = b.readUInt32BE(off); - const type = b.toString('ascii', off + 4, off + 8); - if (type === 'tEXt' || type === 'zTXt') { - const data = b.subarray(off + 8, off + 8 + len); - const nul = data.indexOf(0); - if (nul !== -1 && data.toString('latin1', 0, nul) === KEYWORD) { - if (type === 'tEXt') return data.toString('utf8', nul + 1); - return zlib.inflateSync(data.subarray(nul + 2)).toString('utf8'); - } +function parsePng(buffer) { + const chunks = []; + let prompt = null; + let offset = 8; + while (offset + 12 <= buffer.length) { + const length = buffer.readUInt32BE(offset); + const type = buffer.toString('ascii', offset + 4, offset + 8); + const data = buffer.subarray(offset + 8, offset + 8 + length); + const nul = data.indexOf(0); + const promptChunk = (type === 'tEXt' || type === 'zTXt') + && nul !== -1 && data.toString('latin1', 0, nul) === KEYWORD; + if (prompt == null && promptChunk) { + prompt = type === 'tEXt' + ? data.toString('utf8', nul + 1) + : zlib.inflateSync(data.subarray(nul + 2)).toString('utf8'); } - off += 12 + len; + chunks.push({ offset, type, promptChunk, bytes: buffer.subarray(offset, offset + 12 + length) }); + offset += 12 + length; } - return null; + return { chunks, prompt }; } function readJpegCom(b) { @@ -121,48 +126,34 @@ function readJpegCom(b) { } const sidecar = `${file}.json`; -if (readMode) { - let prompt = null; - if (isPng) prompt = readPngText(buf); - else if (isJpeg) prompt = readJpegCom(buf); - if (prompt == null && fs.existsSync(sidecar)) { - try { prompt = JSON.parse(fs.readFileSync(sidecar, 'utf8')).prompt ?? null; } catch { /* fall through */ } - } +if (args.includes('--read')) { + const prompt = readPrompt(file, buf); if (prompt == null) { console.error('embed-prompt: no embedded prompt found'); process.exit(2); } console.log(prompt); process.exit(0); } -const prompt = argOf('--prompt') ?? (argOf('--prompt-file') ? fs.readFileSync(argOf('--prompt-file'), 'utf8') : null); +const promptFile = argOf('--prompt-file'); +const prompt = argOf('--prompt') ?? (promptFile ? fs.readFileSync(promptFile, 'utf8') : null); if (!prompt) { console.error('embed-prompt: --prompt or --prompt-file required'); process.exit(1); } -if (isPng) { +if (type === 'png') { // Insert (or replace) our tEXt chunk immediately before IEND. - const iend = buf.indexOf(Buffer.from('IEND', 'ascii')) - 4; + const { chunks, prompt: existingPrompt } = parsePng(buf); + const iend = chunks.find((chunk) => chunk.type === 'IEND')?.offset ?? -1; if (iend < 8) { console.error('embed-prompt: malformed PNG'); process.exit(1); } // Drop any existing chunk with our keyword to keep embedding idempotent. - let body = buf.subarray(8, iend); - const existing = readPngText(buf); - if (existing != null) { - const parts = []; - let off = 8; - while (off + 12 <= buf.length && off < iend + 12) { - const len = buf.readUInt32BE(off); - const type = buf.toString('ascii', off + 4, off + 8); - const chunk = buf.subarray(off, off + 12 + len); - const data = buf.subarray(off + 8, off + 8 + len); - const nul = data.indexOf(0); - const ours = (type === 'tEXt' || type === 'zTXt') && nul !== -1 && data.toString('latin1', 0, nul) === KEYWORD; - if (!ours && type !== 'IEND') parts.push(chunk); - off += 12 + len; - } - body = Buffer.concat(parts).subarray(8 * 0); // parts exclude signature - fs.writeFileSync(file, Buffer.concat([buf.subarray(0, 8), body, pngChunk('tEXt', Buffer.concat([Buffer.from(KEYWORD, 'latin1'), Buffer.from([0]), Buffer.from(prompt, 'utf8')])), pngChunk('IEND', Buffer.alloc(0))])); - } else { - fs.writeFileSync(file, Buffer.concat([buf.subarray(0, iend), pngChunk('tEXt', Buffer.concat([Buffer.from(KEYWORD, 'latin1'), Buffer.from([0]), Buffer.from(prompt, 'utf8')])), buf.subarray(iend)])); - } + const replacing = existingPrompt != null; + const body = replacing + ? Buffer.concat(chunks + .filter((chunk) => chunk.offset < iend && !chunk.promptChunk) + .map((chunk) => chunk.bytes)) + : buf.subarray(8, iend); + const promptChunk = pngChunk('tEXt', Buffer.concat([Buffer.from(KEYWORD, 'latin1'), Buffer.from([0]), Buffer.from(prompt, 'utf8')])); + const end = replacing ? pngChunk('IEND', Buffer.alloc(0)) : buf.subarray(iend); + fs.writeFileSync(file, Buffer.concat([buf.subarray(0, 8), body, promptChunk, end])); console.log(`EMBEDDED: ${file} (png tEXt, ${prompt.length} chars)`); -} else if (isJpeg) { +} else if (type === 'jpeg') { const seg = Buffer.from(`${KEYWORD}\0${prompt}`, 'utf8'); if (seg.length + 2 > 0xffff) { console.error('embed-prompt: prompt too long for a JPEG segment'); process.exit(1); } const com = Buffer.alloc(4 + seg.length); diff --git a/tests/new-work-e2e.test.mjs b/tests/new-work-e2e.test.mjs index 810cfeac2..7a4b863d2 100644 --- a/tests/new-work-e2e.test.mjs +++ b/tests/new-work-e2e.test.mjs @@ -28,6 +28,7 @@ import { runUserBot } from './new-work-e2e/user-bot.mjs'; const ROOT = path.resolve(path.dirname(fileURLToPath(import.meta.url)), '..'); const SERVE = path.join(ROOT, 'skill', 'scripts', 'serve-question.mjs'); const GENERATE = path.join(ROOT, 'skill', 'scripts', 'generate-image.mjs'); +const EMBED_PROMPT = path.join(ROOT, 'skill', 'scripts', 'embed-prompt.mjs'); const CATALOG_DIR = path.join(ROOT, 'tests', 'fixtures', 'concept-catalog'); let playwright; @@ -120,6 +121,10 @@ function spawnSyncGen(prompt, out, size = null) { }); } +function spawnSyncEmbed(args) { + return spawnSync(process.execPath, [EMBED_PROMPT, ...args], { encoding: 'utf8' }); +} + // -------------------------------------------------------------------------- // serve-question interactive cycles // -------------------------------------------------------------------------- @@ -1013,6 +1018,57 @@ describe('new-work-e2e: fake image generation', () => { } }); + it('reads, scans, and idempotently replaces the prompt embedded in a PNG', () => { + const cwd = mkdtempSync(path.join(tmpdir(), 'new-work-img-')); + try { + const image = makeFakeImage(cwd, 'synthetic IEND source prompt', 'comp.png'); + const original = readFileSync(image); + assert.ok(original.indexOf(Buffer.from('IEND')) < original.lastIndexOf(Buffer.from('IEND')), + 'the fixture carries IEND bytes in metadata before the real terminator chunk'); + + const first = spawnSyncEmbed([image, '--prompt', 'first production prompt']); + assert.equal(first.status, 0, first.stderr); + assert.equal(spawnSyncEmbed([image, '--read']).stdout.trim(), 'first production prompt'); + + const scan = spawnSyncEmbed(['--scan', cwd]); + assert.equal(scan.status, 0, scan.stderr); + assert.match(scan.stdout, /SCAN: 1 raster, 0 missing/); + + const second = spawnSyncEmbed([image, '--prompt', 'replacement production prompt']); + assert.equal(second.status, 0, second.stderr); + assert.equal(spawnSyncEmbed([image, '--read']).stdout.trim(), 'replacement production prompt'); + + const bytes = readFileSync(image); + assert.equal(bytes.toString().match(/impeccable:prompt/g)?.length, 1, + 're-embedding replaces the existing metadata instead of accumulating chunks'); + assert.ok(bytes.includes(Buffer.from('SYNTHETIC')), + 'replacing the prompt preserves unrelated PNG metadata'); + } finally { + rmSync(cwd, { recursive: true, force: true }); + } + }); + + it('reads JPEG comments and sidecar fallbacks through the same scan contract', () => { + const cwd = mkdtempSync(path.join(tmpdir(), 'new-work-img-')); + try { + const jpeg = path.join(cwd, 'reference.jpg'); + const webp = path.join(cwd, 'reference.webp'); + writeFileSync(jpeg, Buffer.from([0xff, 0xd8, 0xff, 0xda, 0x00, 0x02])); + writeFileSync(webp, Buffer.from('RIFF placeholder WEBP')); + + assert.equal(spawnSyncEmbed([jpeg, '--prompt', 'jpeg prompt']).status, 0); + assert.equal(spawnSyncEmbed([webp, '--prompt', 'sidecar prompt']).status, 0); + assert.equal(spawnSyncEmbed([jpeg, '--read']).stdout.trim(), 'jpeg prompt'); + assert.equal(spawnSyncEmbed([webp, '--read']).stdout.trim(), 'sidecar prompt'); + + const scan = spawnSyncEmbed(['--scan', cwd]); + assert.equal(scan.status, 0, scan.stderr); + assert.match(scan.stdout, /SCAN: 2 rasters, 0 missing/); + } finally { + rmSync(cwd, { recursive: true, force: true }); + } + }); + it('the SVG variant carries the readable prompt text and SYNTHETIC COMP label', () => { const cwd = mkdtempSync(path.join(tmpdir(), 'new-work-img-')); try {