Add Deno.realpath (#3404)

6 files changed, 129 insertions, 0 deletions

diff --git a/cli/js/deno.ts b/cli/js/deno.ts
index 2a7274727..6f07bef67 100644
--- a/cli/js/deno.ts
+++ b/cli/js/deno.ts
@@ -56,6 +56,7 @@ export { chownSync, chown } from "./chown.ts";
 export { utimeSync, utime } from "./utime.ts";
 export { removeSync, remove, RemoveOption } from "./remove.ts";
 export { renameSync, rename } from "./rename.ts";
+export { realpathSync, realpath } from "./realpath.ts";
 export { readFileSync, readFile } from "./read_file.ts";
 export { readDirSync, readDir } from "./read_dir.ts";
 export { copyFileSync, copyFile } from "./copy_file.ts";
diff --git a/cli/js/dispatch.ts b/cli/js/dispatch.ts
index c2690ad32..35806c3ad 100644
--- a/cli/js/dispatch.ts
+++ b/cli/js/dispatch.ts
@@ -55,6 +55,7 @@ export let OP_CHOWN: number;
 export let OP_REMOVE: number;
 export let OP_COPY_FILE: number;
 export let OP_STAT: number;
+export let OP_REALPATH: number;
 export let OP_READ_DIR: number;
 export let OP_RENAME: number;
 export let OP_LINK: number;
@@ -97,6 +98,7 @@ export function asyncMsgFromRust(opId: number, ui8: Uint8Array): void {
     case OP_REMOVE:
     case OP_COPY_FILE:
     case OP_STAT:
+    case OP_REALPATH:
     case OP_READ_DIR:
     case OP_RENAME:
     case OP_LINK:
diff --git a/cli/js/lib.deno_runtime.d.ts b/cli/js/lib.deno_runtime.d.ts
index 3fdc28a54..fb7767aa6 100644
--- a/cli/js/lib.deno_runtime.d.ts
+++ b/cli/js/lib.deno_runtime.d.ts
@@ -605,6 +605,21 @@ declare namespace Deno {
     isSymlink(): boolean;
   }
 
+  // @url js/realpath.d.ts
+
+  /** Returns absolute normalized path with symbolic links resolved
+   * synchronously.
+   *
+   *       const realPath = Deno.realpathSync("./some/path");
+   */
+  export function realpathSync(path: string): string;
+
+  /** Returns absolute normalized path with symbolic links resolved.
+   *
+   *       const realPath = await Deno.realpath("./some/path");
+   */
+  export function realpath(path: string): Promise<string>;
+
   // @url js/read_dir.d.ts
 
   /** Reads the directory given by path and returns a list of file info
diff --git a/cli/js/realpath.ts b/cli/js/realpath.ts
new file mode 100644
index 000000000..c17a0f564
--- /dev/null
+++ b/cli/js/realpath.ts
@@ -0,0 +1,19 @@
+// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+import { sendSync, sendAsync } from "./dispatch_json.ts";
+import * as dispatch from "./dispatch.ts";
+
+/** Returns absolute normalized path with symbolic links resolved synchronously.
+ *
+ *       const realPath = Deno.realpathSync("./some/path");
+ */
+export function realpathSync(path: string): string {
+  return sendSync(dispatch.OP_REALPATH, { path });
+}
+
+/** Returns absolute normalized path with symbolic links resolved.
+ *
+ *       const realPath = await Deno.realpath("./some/path");
+ */
+export async function realpath(path: string): Promise<string> {
+  return await sendAsync(dispatch.OP_REALPATH, { path });
+}
diff --git a/cli/js/realpath_test.ts b/cli/js/realpath_test.ts
new file mode 100644
index 000000000..1dc976578
--- /dev/null
+++ b/cli/js/realpath_test.ts
@@ -0,0 +1,91 @@
+// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+import { testPerm, assert, assertEquals } from "./test_util.ts";
+
+testPerm({ read: true }, function realpathSyncSuccess(): void {
+  const incompletePath = "cli/tests/fixture.json";
+  const realPath = Deno.realpathSync(incompletePath);
+  assert(realPath.startsWith("/"));
+  assert(realPath.endsWith(incompletePath));
+});
+
+if (Deno.build.os !== "win") {
+  testPerm({ read: true, write: true }, function realpathSyncSymlink(): void {
+    const testDir = Deno.makeTempDirSync();
+    const target = testDir + "/target";
+    const symlink = testDir + "/symln";
+    Deno.mkdirSync(target);
+    Deno.symlinkSync(target, symlink);
+    const targetPath = Deno.realpathSync(symlink);
+    assert(targetPath.startsWith("/"));
+    assert(targetPath.endsWith("/target"));
+  });
+}
+
+testPerm({ read: false }, function realpathSyncPerm(): void {
+  let caughtError = false;
+  try {
+    Deno.realpathSync("some_file");
+  } catch (e) {
+    caughtError = true;
+    assertEquals(e.kind, Deno.ErrorKind.PermissionDenied);
+    assertEquals(e.name, "PermissionDenied");
+  }
+  assert(caughtError);
+});
+
+testPerm({ read: true }, function realpathSyncNotFound(): void {
+  let caughtError = false;
+  try {
+    Deno.realpathSync("bad_filename");
+  } catch (e) {
+    caughtError = true;
+    assertEquals(e.kind, Deno.ErrorKind.NotFound);
+  }
+  assert(caughtError);
+});
+
+testPerm({ read: true }, async function realpathSuccess(): Promise<void> {
+  const incompletePath = "cli/tests/fixture.json";
+  const realPath = await Deno.realpath(incompletePath);
+  assert(realPath.startsWith("/"));
+  assert(realPath.endsWith(incompletePath));
+});
+
+if (Deno.build.os !== "win") {
+  testPerm(
+    { read: true, write: true },
+    async function realpathSymlink(): Promise<void> {
+      const testDir = Deno.makeTempDirSync();
+      const target = testDir + "/target";
+      const symlink = testDir + "/symln";
+      Deno.mkdirSync(target);
+      Deno.symlinkSync(target, symlink);
+      const targetPath = await Deno.realpath(symlink);
+      assert(targetPath.startsWith("/"));
+      assert(targetPath.endsWith("/target"));
+    }
+  );
+}
+
+testPerm({ read: false }, async function realpathPerm(): Promise<void> {
+  let caughtError = false;
+  try {
+    await Deno.realpath("some_file");
+  } catch (e) {
+    caughtError = true;
+    assertEquals(e.kind, Deno.ErrorKind.PermissionDenied);
+    assertEquals(e.name, "PermissionDenied");
+  }
+  assert(caughtError);
+});
+
+testPerm({ read: true }, async function realpathNotFound(): Promise<void> {
+  let caughtError = false;
+  try {
+    await Deno.realpath("bad_filename");
+  } catch (e) {
+    caughtError = true;
+    assertEquals(e.kind, Deno.ErrorKind.NotFound);
+  }
+  assert(caughtError);
+});
diff --git a/cli/js/unit_tests.ts b/cli/js/unit_tests.ts
index b5d85fcc8..c63fc5f26 100644
--- a/cli/js/unit_tests.ts
+++ b/cli/js/unit_tests.ts
@@ -33,6 +33,7 @@ import "./mkdir_test.ts";
 import "./net_test.ts";
 import "./os_test.ts";
 import "./process_test.ts";
+import "./realpath_test.ts";
 import "./read_dir_test.ts";
 import "./read_file_test.ts";
 import "./read_link_test.ts";