Add homeDir to Deno namespace (#2578)

cli/msg.fbs

@@ -74,6 +74,8 @@ union Any {
   StatRes,
   Symlink,
   Truncate,
+  HomeDir,
+  HomeDirRes,
   Utime,
   WorkerGetMessage,
   WorkerGetMessageRes,
@@ -446,6 +448,12 @@ table Truncate {
   len: uint;
 }
 
+table HomeDir {}
+
+table HomeDirRes {
+  path: string;
+}
+
 table Utime {
   filename: string;
   atime: uint64;

cli/ops.rs

@@ -241,6 +241,7 @@ pub fn op_selector_std(inner_type: msg::Any) -> Option<CliDispatchFn> {
     msg::Any::Stat => Some(op_stat),
     msg::Any::Symlink => Some(op_symlink),
     msg::Any::Truncate => Some(op_truncate),
+    msg::Any::HomeDir => Some(op_home_dir),
     msg::Any::Utime => Some(op_utime),
     msg::Any::Write => Some(op_write),
 
@@ -1718,6 +1719,34 @@ fn op_metrics(
   ))
 }
 
+fn op_home_dir(
+  _state: &ThreadSafeState,
+  base: &msg::Base<'_>,
+  data: Option<PinnedBuf>,
+) -> CliOpResult {
+  assert!(data.is_none());
+  let cmd_id = base.cmd_id();
+
+  let builder = &mut FlatBufferBuilder::new();
+  let path = dirs::home_dir()
+    .unwrap_or_default()
+    .into_os_string()
+    .into_string()
+    .unwrap_or_default();
+  let path = Some(builder.create_string(&path));
+  let inner = msg::HomeDirRes::create(builder, &msg::HomeDirResArgs { path });
+
+  ok_buf(serialize_response(
+    cmd_id,
+    builder,
+    msg::BaseArgs {
+      inner: Some(inner.as_union_value()),
+      inner_type: msg::Any::HomeDirRes,
+      ..Default::default()
+    },
+  ))
+}
+
 fn op_resources(
   _state: &ThreadSafeState,
   base: &msg::Base<'_>,

js/deno.ts

@@ -1,7 +1,7 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
 
 // Public deno module.
-export { noColor, pid, env, exit, isTTY, execPath } from "./os";
+export { noColor, pid, env, exit, isTTY, execPath, homeDir } from "./os";
 export { chdir, cwd } from "./dir";
 export {
   File,

js/os.ts

@@ -130,3 +130,23 @@ export function start(source?: string): msg.StartRes {
 
   return startResMsg;
 }
+
+/**
+ * Returns the current user's home directory.
+ * Does not require elevated privileges.
+ */
+export function homeDir(): string {
+  const builder = flatbuffers.createBuilder();
+  const inner = msg.HomeDir.createHomeDir(builder);
+  const baseRes = sendSync(builder, msg.Any.HomeDir, inner)!;
+  assert(msg.Any.HomeDirRes === baseRes.innerType());
+  const res = new msg.HomeDirRes();
+  assert(baseRes.inner(res) != null);
+  const path = res.path();
+
+  if (!path) {
+    throw new Error("Could not get home directory.");
+  }
+
+  return path;
+}

js/os_test.ts

@@ -1,5 +1,11 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
-import { test, testPerm, assert, assertEquals } from "./test_util.ts";
+import {
+  test,
+  testPerm,
+  assert,
+  assertEquals,
+  assertNotEquals
+} from "./test_util.ts";
 
 testPerm({ env: true }, function envSuccess(): void {
   const env = Deno.env();
@@ -32,3 +38,7 @@ test(function osPid(): void {
 test(function osIsTTYSmoke(): void {
   console.log(Deno.isTTY());
 });
+
+test(function homeDir(): void {
+  assertNotEquals(Deno.homeDir(), "");
+});