2 files changed, 178 insertions, 0 deletions
diff --git a/std b/std
deleted file mode 160000
-Subproject 43aafbf33285753e7b42230f0eb7969b300f71c
diff --git a/std/fs/walk.ts b/std/fs/walk.ts
new file mode 100644
index 000000000..16ccc357e
--- /dev/null
+++ b/std/fs/walk.ts
@@ -0,0 +1,178 @@
+// Documentation and interface for walk were adapted from Go
+// https://golang.org/pkg/path/filepath/#Walk
+// Copyright 2009 The Go Authors. All rights reserved. BSD license.
+import { unimplemented } from "../testing/asserts.ts";
+import { join } from "./path/mod.ts";
+const { readDir, readDirSync, stat, statSync } = Deno;
+type FileInfo = Deno.FileInfo;
+
+export interface WalkOptions {
+  maxDepth?: number;
+  includeFiles?: boolean;
+  includeDirs?: boolean;
+  followSymlinks?: boolean;
+  exts?: string[];
+  match?: RegExp[];
+  skip?: RegExp[];
+  onError?: (err: Error) => void;
+}
+
+function patternTest(patterns: RegExp[], path: string): boolean {
+  // Forced to reset last index on regex while iterating for have
+  // consistent results.
+  // See: https://stackoverflow.com/a/1520853
+  return patterns.some(
+    (pattern): boolean => {
+      const r = pattern.test(path);
+      pattern.lastIndex = 0;
+      return r;
+    }
+  );
+}
+
+function include(filename: string, options: WalkOptions): boolean {
+  if (
+    options.exts &&
+    !options.exts.some((ext): boolean => filename.endsWith(ext))
+  ) {
+    return false;
+  }
+  if (options.match && !patternTest(options.match, filename)) {
+    return false;
+  }
+  if (options.skip && patternTest(options.skip, filename)) {
+    return false;
+  }
+  return true;
+}
+
+export interface WalkInfo {
+  filename: string;
+  info: FileInfo;
+}
+
+/** Walks the file tree rooted at root, yielding each file or directory in the
+ * tree filtered according to the given options. The files are walked in lexical
+ * order, which makes the output deterministic but means that for very large
+ * directories walk() can be inefficient.
+ *
+ * Options:
+ * - maxDepth?: number = Infinity;
+ * - includeFiles?: boolean = true;
+ * - includeDirs?: boolean = true;
+ * - followSymlinks?: boolean = false;
+ * - exts?: string[];
+ * - match?: RegExp[];
+ * - skip?: RegExp[];
+ * - onError?: (err: Error) => void;
+ *
+ *      for await (const { filename, info } of walk(".")) {
+ *        console.log(filename);
+ *        assert(info.isFile());
+ *      };
+ */
+export async function* walk(
+  root: string,
+  options: WalkOptions = {}
+): AsyncIterableIterator<WalkInfo> {
+  const maxDepth = options.maxDepth != undefined ? options.maxDepth! : Infinity;
+  if (maxDepth < 0) {
+    return;
+  }
+  if (options.includeDirs != false && include(root, options)) {
+    let rootInfo: FileInfo;
+    try {
+      rootInfo = await stat(root);
+    } catch (err) {
+      if (options.onError) {
+        options.onError(err);
+        return;
+      }
+    }
+    yield { filename: root, info: rootInfo! };
+  }
+  if (maxDepth < 1 || patternTest(options.skip || [], root)) {
+    return;
+  }
+  let ls: FileInfo[] = [];
+  try {
+    ls = await readDir(root);
+  } catch (err) {
+    if (options.onError) {
+      options.onError(err);
+    }
+  }
+  for (const info of ls) {
+    if (info.isSymlink()) {
+      if (options.followSymlinks) {
+        // TODO(ry) Re-enable followSymlinks.
+        unimplemented();
+      } else {
+        continue;
+      }
+    }
+
+    const filename = join(root, info.name!);
+
+    if (info.isFile()) {
+      if (options.includeFiles != false && include(filename, options)) {
+        yield { filename, info };
+      }
+    } else {
+      yield* walk(filename, { ...options, maxDepth: maxDepth - 1 });
+    }
+  }
+}
+
+/** Same as walk() but uses synchronous ops */
+export function* walkSync(
+  root: string,
+  options: WalkOptions = {}
+): IterableIterator<WalkInfo> {
+  const maxDepth = options.maxDepth != undefined ? options.maxDepth! : Infinity;
+  if (maxDepth < 0) {
+    return;
+  }
+  if (options.includeDirs != false && include(root, options)) {
+    let rootInfo: FileInfo;
+    try {
+      rootInfo = statSync(root);
+    } catch (err) {
+      if (options.onError) {
+        options.onError(err);
+        return;
+      }
+    }
+    yield { filename: root, info: rootInfo! };
+  }
+  if (maxDepth < 1 || patternTest(options.skip || [], root)) {
+    return;
+  }
+  let ls: FileInfo[] = [];
+  try {
+    ls = readDirSync(root);
+  } catch (err) {
+    if (options.onError) {
+      options.onError(err);
+    }
+  }
+  for (const info of ls) {
+    if (info.isSymlink()) {
+      if (options.followSymlinks) {
+        unimplemented();
+      } else {
+        continue;
+      }
+    }
+
+    const filename = join(root, info.name!);
+
+    if (info.isFile()) {
+      if (options.includeFiles != false && include(filename, options)) {
+        yield { filename, info };
+      }
+    } else {
+      yield* walkSync(filename, { ...options, maxDepth: maxDepth - 1 });
+    }
+  }
+}