Split into modules and reorganize

src/generate.ts

@@ -0,0 +1,97 @@
+import { Cache, Project, Report, structUtils } from "@yarnpkg/core";
+import { Filename, PortablePath, ppath, xfs } from "@yarnpkg/fslib";
+
+import defaultExprTmpl from "./tmpl/default.nix.in";
+import projectExprTmpl from "./tmpl/yarn-project.nix.in";
+
+// Generator function that runs after `yarn install`.
+export default async (project: Project, cache: Cache, report: Report) => {
+  const { configuration, cwd } = project;
+  const yarnPathAbs = configuration.get(`yarnPath`);
+  const cacheFolderAbs = configuration.get(`cacheFolder`);
+
+  let yarnPath = ppath.relative(cwd, yarnPathAbs);
+  if (yarnPath.startsWith(`../`)) {
+    yarnPath = yarnPathAbs;
+    report.reportWarning(
+      0,
+      `The Yarn path ${yarnPathAbs} is outside the project - it may not be reachable by the Nix build`
+    );
+  }
+
+  let cacheFolder = ppath.relative(cwd, cacheFolderAbs);
+  if (cacheFolder.startsWith(`../`)) {
+    cacheFolder = cacheFolderAbs;
+    report.reportWarning(
+      0,
+      `The cache folder ${cacheFolderAbs} is outside the project - it may not be reachable by the Nix build`
+    );
+  }
+
+  for (const source of configuration.sources.values()) {
+    if (!source.startsWith(`<`)) {
+      const relativeSource = ppath.relative(cwd, source as PortablePath);
+      if (relativeSource.startsWith(`../`)) {
+        report.reportWarning(
+          0,
+          `The config file ${source} is outside the project - it may not be reachable by the Nix build`
+        );
+      }
+    }
+  }
+
+  // Build a list of cache entries so Nix can fetch them.
+  let cacheEntries = [];
+  const cacheFiles = new Set(xfs.readdirSync(cache.cwd));
+  for (const pkg of project.storedPackages.values()) {
+    const checksum = project.storedChecksums.get(pkg.locatorHash);
+    if (!checksum) continue;
+
+    const cachePath = cache.getLocatorPath(pkg, checksum);
+    if (!cachePath) continue;
+
+    const filename = ppath.basename(cachePath);
+    if (!cacheFiles.has(filename)) continue;
+
+    let name = structUtils.slugifyIdent(pkg).replace(/^@/, "_at_");
+    if (pkg.version) {
+      name += `-${pkg.version}`;
+    }
+
+    const sha512 = checksum.split(`/`).pop();
+    cacheEntries.push([
+      `name = ${JSON.stringify(name)};`,
+      `filename = ${JSON.stringify(filename)};`,
+      `sha512 = ${JSON.stringify(sha512)};`,
+      `locatorHash = ${JSON.stringify(pkg.locatorHash)};`,
+    ]);
+  }
+
+  // Render the Nix expression.
+  const ident = project.topLevelWorkspace.manifest.name;
+  const projectName = ident ? structUtils.stringifyIdent(ident) : `workspace`;
+  const projectExpr = projectExprTmpl
+    .replace(`@@PROJECT_NAME@@`, JSON.stringify(projectName))
+    .replace(`@@YARN_PATH@@`, JSON.stringify(yarnPath))
+    .replace(`@@CACHE_FOLDER@@`, JSON.stringify(cacheFolder))
+    .replace(
+      `@@CACHE_ENTRIES@@`,
+      `[\n` +
+        [...cacheEntries]
+          .map((entry) => `    { ${entry.join(` `)} }\n`)
+          .join(``) +
+        `  ]`
+    );
+  const projectExprPath = ppath.join(cwd, `yarn-project.nix` as Filename);
+  xfs.writeFileSync(projectExprPath, projectExpr);
+
+  // Create a wrapper if it does not exist yet.
+  const defaultExprPath = ppath.join(cwd, `default.nix` as Filename);
+  if (!xfs.existsSync(defaultExprPath)) {
+    xfs.writeFileSync(defaultExprPath, defaultExprTmpl);
+    report.reportInfo(
+      0,
+      `A minimal default.nix was created. You may want to customize it.`
+    );
+  }
+};