10f - plainMarkdownToAdf mints task localIds as UUID v4s hashed from the markdown and position

src/markdown/parse/task-ids.ts

@@ -0,0 +1,71 @@
+import type { AdfDocument, AdfNode } from '../../adf/document.ts'
+import { blockNodeModel } from '../../adf/block-nodes.ts'
+import { nodeAttrs, nodeContent } from '../../adf/document.ts'
+
+const taskTypes = new Set(['blockTaskItem', 'taskItem', 'taskList'])
+
+// docs/decisions.md, Plain task ids come from position.
+export function mintTaskIds(document: AdfDocument, markdown: string): void {
+  const taken = new Set<string>()
+  for (const node of preorder(document, () => true)) {
+    const localId = nodeAttrs(node)['localId']
+    if (typeof localId === 'string') taken.add(localId)
+  }
+  const seed = hash128(markdown).join(' ')
+  let count = 0
+  for (const node of preorder(document, (held) => blockNodeModel(held.type) !== undefined)) {
+    if (!taskTypes.has(node.type) || typeof nodeAttrs(node)['localId'] === 'string') continue
+    let localId = ''
+    do {
+      count += 1
+      localId = uuidV4(hash128(`${seed} ${count}`))
+    } while (taken.has(localId))
+    taken.add(localId)
+    node.attrs = { ...node.attrs, localId }
+  }
+}
+
+function* preorder(document: AdfDocument, entered: (node: AdfNode) => boolean): Generator<AdfNode> {
+  const pending: AdfNode[] = []
+  const pushReversed = (nodes: readonly AdfNode[]): void => {
+    for (let index = nodes.length - 1; index >= 0; index -= 1) {
+      const node = nodes[index]
+      if (node !== undefined) pending.push(node)
+    }
+  }
+  pushReversed(document.content ?? [])
+  for (let node = pending.pop(); node !== undefined; node = pending.pop()) {
+    yield node
+    if (entered(node)) pushReversed(nodeContent(node))
+  }
+}
+
+// cyrb128, public domain.
+function hash128(text: string): number[] {
+  let h1 = 1779033703
+  let h2 = 3144134277
+  let h3 = 1013904242
+  let h4 = 2773480762
+  for (let index = 0; index < text.length; index += 1) {
+    const unit = text.charCodeAt(index)
+    h1 = h2 ^ Math.imul(h1 ^ unit, 597399067)
+    h2 = h3 ^ Math.imul(h2 ^ unit, 2869860233)
+    h3 = h4 ^ Math.imul(h3 ^ unit, 951274213)
+    h4 = h1 ^ Math.imul(h4 ^ unit, 2716044179)
+  }
+  h1 = Math.imul(h3 ^ (h1 >>> 18), 597399067)
+  h2 = Math.imul(h4 ^ (h2 >>> 22), 2869860233)
+  h3 = Math.imul(h1 ^ (h3 >>> 17), 951274213)
+  h4 = Math.imul(h2 ^ (h4 >>> 19), 2716044179)
+  h1 ^= h2 ^ h3 ^ h4
+  h2 ^= h1
+  h3 ^= h1
+  h4 ^= h1
+  return [h1 >>> 0, h2 >>> 0, h3 >>> 0, h4 >>> 0]
+}
+
+function uuidV4(lanes: readonly number[]): string {
+  const hex = lanes.map((lane) => lane.toString(16).padStart(8, '0')).join('')
+  const variant = ((Number.parseInt(hex.charAt(16), 16) & 3) | 8).toString(16)
+  return `${hex.slice(0, 8)}-${hex.slice(8, 12)}-4${hex.slice(13, 16)}-${variant}${hex.slice(17, 20)}-${hex.slice(20, 32)}`
+}