Initial commit

scripts/patches/lib.mjs

@@ -0,0 +1,66 @@
+import { createHash } from "node:crypto";
+import { cpSync, existsSync, mkdirSync, readFileSync, readdirSync, statSync } from "node:fs";
+import path from "node:path";
+
+export function countOccurrences(source, needle) {
+  if (needle.length === 0) throw new Error("Patch needle must not be empty");
+  let count = 0;
+  let offset = 0;
+  while ((offset = source.indexOf(needle, offset)) !== -1) {
+    count += 1;
+    offset += needle.length;
+  }
+  return count;
+}
+
+export function replaceExactly(source, needle, replacement, label) {
+  const matches = countOccurrences(source, needle);
+  if (matches !== 1) {
+    throw new Error(`${label}: expected exactly one semantic anchor, found ${matches}`);
+  }
+  return source.replace(needle, replacement);
+}
+
+export function markerStatus(source, marker) {
+  const matches = countOccurrences(source, marker);
+  if (matches > 1) throw new Error(`Patch marker '${marker}' occurs ${matches} times`);
+  return matches === 1 ? "already-applied" : null;
+}
+
+export function copyTreeContents(sourceDir, destinationDir) {
+  if (!existsSync(sourceDir) || !statSync(sourceDir).isDirectory()) {
+    throw new Error(`Replacement tree is not a directory: ${sourceDir}`);
+  }
+  mkdirSync(destinationDir, { recursive: true });
+  for (const entry of readdirSync(sourceDir, { withFileTypes: true })) {
+    cpSync(path.join(sourceDir, entry.name), path.join(destinationDir, entry.name), {
+      recursive: true,
+      force: true,
+      dereference: false,
+    });
+  }
+}
+
+export function sha256File(filePath) {
+  return createHash("sha256").update(readFileSync(filePath)).digest("hex");
+}
+
+export function walkFiles(root) {
+  if (!existsSync(root)) return [];
+  const files = [];
+  const visit = (directory) => {
+    for (const entry of readdirSync(directory, { withFileTypes: true })) {
+      const fullPath = path.join(directory, entry.name);
+      if (entry.isDirectory()) visit(fullPath);
+      else if (entry.isFile()) files.push(fullPath);
+    }
+  };
+  visit(root);
+  return files.sort((left, right) => left.localeCompare(right));
+}
+
+export function relativeFileHashes(root) {
+  return Object.fromEntries(
+    walkFiles(root).map((filePath) => [path.relative(root, filePath), sha256File(filePath)]),
+  );
+}