Move patch alignment into whiteboard-document

packages/board-protocol/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@dev.fast/board-protocol",
-  "version": "0.1.3",
+  "version": "0.1.4",
   "description": "Wire contract between a hosted whiteboard board server and its clients.",
   "license": "MIT",
   "repository": {

packages/review/app/src/share/peeks.real-diffs.browser.test.ts

@@ -6,7 +6,7 @@ import type {
   ShareAlignment,
   ShareSource,
 } from "@dev.fast/review-share-protocol";
-import { textualRows } from "@review/review-api/lens-alignment";
+import { patchRows } from "@dev.fast/whiteboard-document";
 import { type DiffHunk, parseUnifiedPatch } from "@review/unified-diff";
 import { afterEach, describe, expect, it } from "vitest";
 
@@ -60,8 +60,7 @@ const lineCount = (text: string | null) =>
 function share(fixture: Fixture) {
   const pins = { repositoryId: "repo", base: fixture.base, head: fixture.head };
 
-  const rows = textualRows(
-    fixture.file,
+  const rows = patchRows(
     fixture.patch,
     lineCount(fixture.baseText),
     lineCount(fixture.headText),

packages/review/src/lens-selection.test.ts

@@ -3,6 +3,7 @@ import {
   anchorSelection,
   formatAnchor,
   parseAnchor,
+  patchRows,
   resolveDiffSelection,
   selectSource,
   selectionKey,
@@ -11,7 +12,6 @@ import {
 } from "@dev.fast/whiteboard-document";
 import { expect, it } from "vitest";
 
-import { textualRows } from "./review-api/lens-alignment.js";
 import {
   type CoverageFile,
   coverageProgress,
@@ -122,12 +122,7 @@ it("rejects stale or reversed endpoints instead of inventing correspondence", ()
 });
 
 it("resolves selections over existing textual hunks, including unchanged gaps", () => {
-  const alignment = textualRows(
-    "a",
-    "@@ -2,2 +2,1 @@\n-deleted\n context",
-    4,
-    3,
-  );
+  const alignment = patchRows("@@ -2,2 +2,1 @@\n-deleted\n context", 4, 3);
 
   expect(
     resolveDiffSelection(

packages/review/src/review-api/comparison-coverage.ts

@@ -7,10 +7,11 @@ import {
   applyStructuralUpdate,
   structuralRows,
 } from "@dev.fast/review-protocol";
-import type {
-  AlignmentRow,
-  FileLineRange,
-  Pins,
+import {
+  type AlignmentRow,
+  type FileLineRange,
+  type Pins,
+  patchRows,
 } from "@dev.fast/whiteboard-document";
 import { parseUnifiedPatch } from "@review/unified-diff.js";
 import {
@@ -23,7 +24,6 @@ import {
   unionIntervals,
 } from "@review/viewed-coverage.js";
 
-import { textualRows } from "./lens-alignment.js";
 import type { LocalReviewData } from "./local-data.js";
 
 const hash = (parts: (string | null)[]) =>
@@ -91,8 +91,7 @@ export async function comparisonCoverage(
 
     alignments.set(
       file.path,
-      textualRows(
-        file.path,
+      patchRows(
         patch,
         base === null ? 0 : base.split("\n").length,
         head === null ? 0 : head.split("\n").length,

packages/review/src/review-api/review-progress.ts

@@ -13,6 +13,7 @@ import {
   comparisonKey,
   fileLineRangeSchema,
   lensSelections,
+  patchRows,
   resolveDiffSelection,
   selectionKey,
   selectionReferences,
@@ -26,7 +27,6 @@ import {
   resolveFileLens,
   uncategorizedSources,
 } from "./file-lenses.js";
-import { textualRows } from "./lens-alignment.js";
 import type { LocalReviewData } from "./local-data.js";
 import type { ReviewStore, Snapshot } from "./store.js";
 
@@ -208,8 +208,7 @@ export async function reviewProgress(
           "no_alignment",
           "Changed context file has no alignment.",
         );
-      rows = textualRows(
-        source.file,
+      rows = patchRows(
         "",
         base?.split("\n").length ?? 0,
         head?.split("\n").length ?? 0,

packages/whiteboard-document/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@dev.fast/whiteboard-document",
-  "version": "0.2.1",
+  "version": "0.2.2",
   "description": "The whiteboard document: block schemas, the edit reducer and its summary, for any runtime.",
   "license": "MIT",
   "repository": {

packages/whiteboard-document/src/index.ts

@@ -118,6 +118,7 @@ export {
   comparisonKey,
   formatAnchor,
   parseAnchor,
+  patchRows,
   rangeAnchor,
   resolveDiffSelection,
   selectSource,

packages/whiteboard-document/src/lens-selection.test.ts

@@ -0,0 +1,34 @@
+import { expect, it } from "vitest";
+
+import { patchRows } from "./lens-selection.js";
+
+it("pairs a patch's lines, unchanged gaps and the tail included", () => {
+  expect(
+    patchRows(
+      "@@ -2,2 +2,1 @@\n-deleted\n context\n\\ No newline at end of file",
+      4,
+      3,
+    ),
+  ).toEqual([
+    [0, 0],
+    [1, null],
+    [2, 1],
+    [3, 2],
+  ]);
+});
+
+it("pairs an added file's lines with nothing, skipping the git headers", () => {
+  expect(
+    patchRows("--- /dev/null\n+++ b/a\n@@ -0,0 +1,2 @@\n+a\n+b", 0, 2),
+  ).toEqual([
+    [null, 0],
+    [null, 1],
+  ]);
+});
+
+it("pairs each line with itself without a patch", () => {
+  expect(patchRows("", 2, 2)).toEqual([
+    [0, 0],
+    [1, 1],
+  ]);
+});

packages/whiteboard-document/src/lens-selection.ts

@@ -140,6 +140,63 @@ export type LensSource = DiffSelection;
 
 export type AlignmentRow = readonly [number | null, number | null];
 
+const HUNK = /^@@ -(\d+)(?:,(\d+))? \+(\d+)(?:,(\d+))? @@/;
+
+/** The 0-based line pairs a unified patch aligns, unchanged gaps included,
+ * for files of `baseCount` and `headCount` lines. An empty patch pairs each
+ * line with itself. */
+export function patchRows(
+  patch: string,
+  baseCount: number,
+  headCount: number,
+): AlignmentRow[] {
+  const rows: AlignmentRow[] = [];
+  let base = 0;
+  let head = 0;
+  let removed = 0;
+  let added = 0;
+  let inHunk = false;
+
+  const append = (baseEnd: number, headEnd: number) => {
+    while (base < baseEnd || head < headEnd)
+      rows.push([
+        base < baseEnd ? base++ : null,
+        head < headEnd ? head++ : null,
+      ]);
+  };
+
+  const flush = () => {
+    append(base + removed, head + added);
+    removed = added = 0;
+  };
+
+  for (const line of patch.split(/\r?\n/)) {
+    const hunk = HUNK.exec(line);
+
+    if (hunk) {
+      inHunk = true;
+      flush();
+      const [, oldStart, oldLines = "1", newStart, newLines = "1"] = hunk;
+
+      append(
+        Number(oldLines) ? Number(oldStart) - 1 : Number(oldStart),
+        Number(newLines) ? Number(newStart) - 1 : Number(newStart),
+      );
+    } else if (!inHunk) continue;
+    else if (line.startsWith("+")) added++;
+    else if (line.startsWith("-")) removed++;
+    else if (line.startsWith(" ")) {
+      flush();
+      append(base + 1, head + 1);
+    }
+  }
+
+  flush();
+  append(baseCount, headCount);
+
+  return rows;
+}
+
 /** Pins-less selections keep the key they always had. */
 export function selectionKey(source: LensSource): string {
   return JSON.stringify([