Implement deno.symlink() (#742)

BUILD.gn

@@ -76,6 +76,7 @@ ts_sources = [
   "js/remove.ts",
   "js/rename.ts",
   "js/stat.ts",
+  "js/symlink.ts",
   "js/text_encoding.ts",
   "js/timers.ts",
   "js/types.ts",

js/deno.ts

@@ -8,6 +8,7 @@ export { removeSync, remove, removeAllSync, removeAll } from "./remove";
 export { readFileSync, readFile } from "./read_file";
 export { renameSync, rename } from "./rename";
 export { FileInfo, statSync, lstatSync, stat, lstat } from "./stat";
+export { symlinkSync, symlink } from "./symlink";
 export { writeFileSync, writeFile } from "./write_file";
 export { ErrorKind, DenoError } from "./errors";
 export { libdeno } from "./libdeno";

js/symlink.ts

@@ -0,0 +1,56 @@
+// Copyright 2018 the Deno authors. All rights reserved. MIT license.
+import * as fbs from "gen/msg_generated";
+import { flatbuffers } from "flatbuffers";
+import * as dispatch from "./dispatch";
+import * as util from "./util";
+
+/**
+ * Synchronously creates newname as a symbolic link to oldname.
+ * The type argument can be set to 'dir' or 'file' and is only
+ * available on Windows (ignored on other platforms).
+ *
+ *     import { symlinkSync } from "deno";
+ *     symlinkSync("old/name", "new/name");
+ */
+export function symlinkSync(
+  oldname: string,
+  newname: string,
+  type?: string
+): void {
+  dispatch.sendSync(...req(oldname, newname, type));
+}
+
+/**
+ * Creates newname as a symbolic link to oldname.
+ * The type argument can be set to 'dir' or 'file' and is only
+ * available on Windows (ignored on other platforms).
+ *
+ *     import { symlink } from "deno";
+ *     await symlink("old/name", "new/name");
+ */
+export async function symlink(
+  oldname: string,
+  newname: string,
+  type?: string
+): Promise<void> {
+  await dispatch.sendAsync(...req(oldname, newname, type));
+}
+
+function req(
+  oldname: string,
+  newname: string,
+  type?: string
+): [flatbuffers.Builder, fbs.Any, flatbuffers.Offset] {
+  // TODO Use type for Windows.
+  if (type) {
+    return util.notImplemented();
+  }
+  const builder = new flatbuffers.Builder();
+  const oldname_ = builder.createString(oldname);
+  const newname_ = builder.createString(newname);
+  fbs.Symlink.startSymlink(builder);
+  fbs.Symlink.addOldname(builder, oldname_);
+  fbs.Symlink.addNewname(builder, newname_);
+  const msg = fbs.Symlink.endSymlink(builder);
+  return [builder, fbs.Any.Symlink, msg];
+}

js/symlink_test.ts

@@ -0,0 +1,71 @@
+// Copyright 2018 the Deno authors. All rights reserved. MIT license.
+import { test, testPerm, assert, assertEqual } from "./test_util.ts";
+import * as deno from "deno";
+
+testPerm({ write: true }, function symlinkSyncSuccess() {
+  const testDir = deno.makeTempDirSync() + "/test-symlink-sync";
+  const oldname = testDir + "/oldname";
+  const newname = testDir + "/newname";
+  deno.mkdirSync(oldname);
+  let errOnWindows;
+  // Just for now, until we implement symlink for Windows.
+  try {
+    deno.symlinkSync(oldname, newname);
+  } catch (e) {
+    errOnWindows = e;
+  }
+  if (errOnWindows) {
+    assertEqual(errOnWindows.kind, deno.ErrorKind.Other);
+    assertEqual(errOnWindows.message, "Not implemented");
+  } else {
+    const newNameInfoLStat = deno.lstatSync(newname);
+    const newNameInfoStat = deno.statSync(newname);
+    assert(newNameInfoLStat.isSymlink());
+    assert(newNameInfoStat.isDirectory());
+  }
+});
+
+testPerm({ write: false }, function symlinkSyncPerm() {
+  let err;
+  try {
+    deno.symlinkSync("oldbaddir", "newbaddir");
+  } catch (e) {
+    err = e;
+  }
+  assertEqual(err.kind, deno.ErrorKind.PermissionDenied);
+  assertEqual(err.name, "PermissionDenied");
+});
+
+// Just for now, until we implement symlink for Windows.
+testPerm({ write: true }, function symlinkSyncNotImplemented() {
+  let err;
+  try {
+    deno.symlinkSync("oldname", "newname", "dir");
+  } catch (e) {
+    err = e;
+  }
+  assertEqual(err.message, "Not implemented");
+});
+
+testPerm({ write: true }, async function symlinkSuccess() {
+  const testDir = deno.makeTempDirSync() + "/test-symlink";
+  const oldname = testDir + "/oldname";
+  const newname = testDir + "/newname";
+  deno.mkdirSync(oldname);
+  let errOnWindows;
+  // Just for now, until we implement symlink for Windows.
+  try {
+    await deno.symlink(oldname, newname);
+  } catch (e) {
+    errOnWindows = e;
+  }
+  if (errOnWindows) {
+    assertEqual(errOnWindows.kind, deno.ErrorKind.Other);
+    assertEqual(errOnWindows.message, "Not implemented");
+  } else {
+    const newNameInfoLStat = deno.lstatSync(newname);
+    const newNameInfoStat = deno.statSync(newname);
+    assert(newNameInfoLStat.isSymlink());
+    assert(newNameInfoStat.isDirectory());
+  }
+});

js/unit_tests.ts

@@ -13,3 +13,4 @@ import "./stat_test.ts";
 import "./rename_test.ts";
 import "./blob_test.ts";
 import "./timers_test.ts";
+import "./symlink_test.ts";

src/handlers.rs

@@ -56,6 +56,7 @@ pub extern "C" fn msg_from_js(d: *const DenoC, buf: deno_buf) {
     msg::Any::Remove => handle_remove,
     msg::Any::ReadFile => handle_read_file,
     msg::Any::Rename => handle_rename,
+    msg::Any::Symlink => handle_symlink,
     msg::Any::SetEnv => handle_set_env,
     msg::Any::Stat => handle_stat,
     msg::Any::WriteFile => handle_write_file,
@@ -142,6 +143,13 @@ fn permission_denied() -> DenoError {
   ))
 }
 
+fn not_implemented() -> DenoError {
+  DenoError::from(std::io::Error::new(
+    std::io::ErrorKind::Other,
+    "Not implemented"
+  ))
+}
+
 fn handle_exit(_d: *const DenoC, base: &msg::Base) -> Box<Op> {
   let msg = base.msg_as_exit().unwrap();
   std::process::exit(msg.code())
@@ -663,7 +671,7 @@ fn handle_rename(d: *const DenoC, base: &msg::Base) -> Box<Op> {
   let isolate = from_c(d);
   if !isolate.flags.allow_write {
     return odd_future(permission_denied());
-  };
+  }
   let msg = base.msg_as_rename().unwrap();
   let oldpath = String::from(msg.oldpath().unwrap());
   let newpath = String::from(msg.newpath().unwrap());
@@ -673,3 +681,24 @@ fn handle_rename(d: *const DenoC, base: &msg::Base) -> Box<Op> {
     Ok(None)
   }()))
 }
+
+fn handle_symlink(d: *const DenoC, base: &msg::Base) -> Box<Op> {
+  let deno = from_c(d);
+  if !deno.flags.allow_write {
+    return odd_future(permission_denied());
+  }
+  // TODO Use type for Windows.
+  if cfg!(windows) {
+    return odd_future(not_implemented());
+  } else {
+    let msg = base.msg_as_symlink().unwrap();
+    let oldname = String::from(msg.oldname().unwrap());
+    let newname = String::from(msg.newname().unwrap());
+    Box::new(futures::future::result(|| -> OpResult {
+      debug!("handle_symlink {} {}", oldname, newname);
+      #[cfg(any(unix))]
+      std::os::unix::fs::symlink(Path::new(&oldname), Path::new(&newname))?;
+      Ok(None)
+    }()))
+  }
+}

src/msg.fbs

@@ -20,6 +20,7 @@ union Any {
   ReadFileRes,
   WriteFile,
   Rename,
+  Symlink,
   Stat,
   StatRes,
   SetEnv,
@@ -200,6 +201,11 @@ table Rename {
   newpath: string;
 }
 
+table Symlink {
+  oldname: string;
+  newname: string;
+}
+
 table Stat {
   filename: string;
   lstat: bool;