feat(fs): add copy/copySync (#278)

fs/README.md

@@ -129,6 +129,19 @@ moveSync("./foo", "./existingFolder", { overwrite: true });
 // Will overwrite existingFolder
 ```
 
+### copy
+
+copy a file or directory. Overwrites it if option provided
+
+```ts
+import { copy, copySync } from "https://deno.land/std/fs/mod.ts";
+
+copy("./foo", "./bar"); // returns a promise
+copySync("./foo", "./bar"); // void
+copySync("./foo", "./existingFolder", { overwrite: true });
+// Will overwrite existingFolder
+```
+
 ### readJson
 
 Reads a JSON file and then parses it into an object

fs/copy.ts

@@ -0,0 +1,260 @@
+// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+import * as path from "./path/mod.ts";
+import { ensureDir, ensureDirSync } from "./ensure_dir.ts";
+import { isSubdir, getFileInfoType } from "./utils.ts";
+
+export interface CopyOptions {
+  /**
+   * overwrite existing file or directory. Default is `false`
+   */
+  overwrite?: boolean;
+  /**
+   * When `true`, will set last modification and access times to the ones of the original source files.
+   * When `false`, timestamp behavior is OS-dependent.
+   * Default is `false`.
+   */
+  preserveTimestamps?: boolean;
+}
+
+async function ensureValidCopy(
+  src: string,
+  dest: string,
+  options: CopyOptions,
+  isCopyFolder: boolean = false
+): Promise<Deno.FileInfo> {
+  let destStat: Deno.FileInfo;
+
+  destStat = await Deno.lstat(dest).catch(
+    (): Promise<null> => Promise.resolve(null)
+  );
+
+  if (destStat) {
+    if (isCopyFolder && !destStat.isDirectory()) {
+      throw new Error(
+        `Cannot overwrite non-directory '${dest}' with directory '${src}'.`
+      );
+    }
+    if (!options.overwrite) {
+      throw new Error(`'${dest}' already exists.`);
+    }
+  }
+
+  return destStat;
+}
+
+function ensureValidCopySync(
+  src: string,
+  dest: string,
+  options: CopyOptions,
+  isCopyFolder: boolean = false
+): Deno.FileInfo {
+  let destStat: Deno.FileInfo;
+
+  try {
+    destStat = Deno.lstatSync(dest);
+  } catch {
+    // ignore error
+  }
+
+  if (destStat) {
+    if (isCopyFolder && !destStat.isDirectory()) {
+      throw new Error(
+        `Cannot overwrite non-directory '${dest}' with directory '${src}'.`
+      );
+    }
+    if (!options.overwrite) {
+      throw new Error(`'${dest}' already exists.`);
+    }
+  }
+
+  return destStat;
+}
+
+/* copy file to dest */
+async function copyFile(
+  src: string,
+  dest: string,
+  options: CopyOptions
+): Promise<void> {
+  await ensureValidCopy(src, dest, options);
+  await Deno.copyFile(src, dest);
+  if (options.preserveTimestamps) {
+    const statInfo = await Deno.stat(src);
+    await Deno.utime(dest, statInfo.accessed, statInfo.modified);
+  }
+}
+/* copy file to dest synchronously */
+function copyFileSync(src: string, dest: string, options: CopyOptions): void {
+  ensureValidCopySync(src, dest, options);
+  Deno.copyFileSync(src, dest);
+  if (options.preserveTimestamps) {
+    const statInfo = Deno.statSync(src);
+    Deno.utimeSync(dest, statInfo.accessed, statInfo.modified);
+  }
+}
+
+/* copy symlink to dest */
+async function copySymLink(
+  src: string,
+  dest: string,
+  options: CopyOptions
+): Promise<void> {
+  await ensureValidCopy(src, dest, options);
+  const originSrcFilePath = await Deno.readlink(src);
+  const type = getFileInfoType(await Deno.lstat(src));
+  await Deno.symlink(originSrcFilePath, dest, type);
+  if (options.preserveTimestamps) {
+    const statInfo = await Deno.lstat(src);
+    await Deno.utime(dest, statInfo.accessed, statInfo.modified);
+  }
+}
+
+/* copy symlink to dest synchronously */
+function copySymlinkSync(
+  src: string,
+  dest: string,
+  options: CopyOptions
+): void {
+  ensureValidCopySync(src, dest, options);
+  const originSrcFilePath = Deno.readlinkSync(src);
+  const type = getFileInfoType(Deno.lstatSync(src));
+  Deno.symlinkSync(originSrcFilePath, dest, type);
+  if (options.preserveTimestamps) {
+    const statInfo = Deno.lstatSync(src);
+    Deno.utimeSync(dest, statInfo.accessed, statInfo.modified);
+  }
+}
+
+/* copy folder from src to dest. */
+async function copyDir(
+  src: string,
+  dest: string,
+  options: CopyOptions
+): Promise<void> {
+  const destStat = await ensureValidCopy(src, dest, options, true);
+
+  if (!destStat) {
+    await ensureDir(dest);
+  }
+
+  if (options.preserveTimestamps) {
+    const srcStatInfo = await Deno.stat(src);
+    await Deno.utime(dest, srcStatInfo.accessed, srcStatInfo.modified);
+  }
+
+  const files = await Deno.readDir(src);
+
+  for (const file of files) {
+    const srcPath = file.path as string;
+    const destPath = path.join(dest, path.basename(srcPath as string));
+    if (file.isDirectory()) {
+      await copyDir(srcPath, destPath, options);
+    } else if (file.isFile()) {
+      await copyFile(srcPath, destPath, options);
+    } else if (file.isSymlink()) {
+      await copySymLink(srcPath, destPath, options);
+    }
+  }
+}
+
+/* copy folder from src to dest synchronously */
+function copyDirSync(src: string, dest: string, options: CopyOptions): void {
+  const destStat: Deno.FileInfo = ensureValidCopySync(src, dest, options, true);
+
+  if (!destStat) {
+    ensureDirSync(dest);
+  }
+
+  if (options.preserveTimestamps) {
+    const srcStatInfo = Deno.statSync(src);
+    Deno.utimeSync(dest, srcStatInfo.accessed, srcStatInfo.modified);
+  }
+
+  const files = Deno.readDirSync(src);
+
+  for (const file of files) {
+    const srcPath = file.path as string;
+    const destPath = path.join(dest, path.basename(srcPath as string));
+    if (file.isDirectory()) {
+      copyDirSync(srcPath, destPath, options);
+    } else if (file.isFile()) {
+      copyFileSync(srcPath, destPath, options);
+    } else if (file.isSymlink()) {
+      copySymlinkSync(srcPath, destPath, options);
+    }
+  }
+}
+
+/**
+ * Copy a file or directory. The directory can have contents. Like `cp -r`.
+ * @param src the file/directory path.
+ *            Note that if `src` is a directory it will copy everything inside of this directory,
+ *            not the entire directory itself
+ * @param dest the destination path. Note that if `src` is a file, `dest` cannot be a directory
+ * @param options
+ */
+export async function copy(
+  src: string,
+  dest: string,
+  options: CopyOptions = {}
+): Promise<void> {
+  src = path.resolve(src);
+  dest = path.resolve(dest);
+
+  if (src === dest) {
+    throw new Error("Source and destination cannot be the same.");
+  }
+
+  const srcStat = await Deno.lstat(src);
+
+  if (srcStat.isDirectory() && isSubdir(src, dest)) {
+    throw new Error(
+      `Cannot copy '${src}' to a subdirectory of itself, '${dest}'.`
+    );
+  }
+
+  if (srcStat.isDirectory()) {
+    await copyDir(src, dest, options);
+  } else if (srcStat.isFile()) {
+    await copyFile(src, dest, options);
+  } else if (srcStat.isSymlink()) {
+    await copySymLink(src, dest, options);
+  }
+}
+
+/**
+ * Copy a file or directory. The directory can have contents. Like `cp -r`.
+ * @param src the file/directory path.
+ *            Note that if `src` is a directory it will copy everything inside of this directory,
+ *            not the entire directory itself
+ * @param dest the destination path. Note that if `src` is a file, `dest` cannot be a directory
+ * @param options
+ */
+export function copySync(
+  src: string,
+  dest: string,
+  options: CopyOptions = {}
+): void {
+  src = path.resolve(src);
+  dest = path.resolve(dest);
+
+  if (src === dest) {
+    throw new Error("Source and destination cannot be the same.");
+  }
+
+  const srcStat = Deno.lstatSync(src);
+
+  if (srcStat.isDirectory() && isSubdir(src, dest)) {
+    throw new Error(
+      `Cannot copy '${src}' to a subdirectory of itself, '${dest}'.`
+    );
+  }
+
+  if (srcStat.isDirectory()) {
+    copyDirSync(src, dest, options);
+  } else if (srcStat.isFile()) {
+    copyFileSync(src, dest, options);
+  } else if (srcStat.isSymlink()) {
+    copySymlinkSync(src, dest, options);
+  }
+}