fs: Buffer and encoding enhancements to fs API

This makes several changes:

1. Allow path/filename to be passed in as a Buffer on fs methods
2. Add `options.encoding` to fs.readdir, fs.readdirSync, fs.readlink,
   fs.readlinkSync and fs.watch.
3. Documentation updates

For 1... it's now possible to do:

```js
fs.open(Buffer('/fs/foo/bar'), 'w+', (err, fd) => { });
```

For 2...
```js
fs.readdir('/fs/foo/bar', {encoding:'hex'}, (err,list) => { });

fs.readdir('/fs/foo/bar', {encoding:'buffer'}, (err, list) => { });
```

encoding can also be passed as a string

```js
fs.readdir('/fs/foo/bar', 'hex', (err,list) => { });
```

The default encoding is set to UTF8 so this addresses the
discrepency that existed previously between fs.readdir and
fs.watch handling filenames differently.

Fixes: https://github.com/nodejs/node/issues/2088
Refs: https://github.com/nodejs/node/issues/3519
PR-URL: https://github.com/nodejs/node/pull/5616
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Trevor Norris <trev.norris@gmail.com>

1 files changed, 22 insertions, 5 deletions

diff --git a/src/fs_event_wrap.cc b/src/fs_event_wrap.cc
index 7768f94459c..58f2716a6c0 100644
--- a/src/fs_event_wrap.cc
+++ b/src/fs_event_wrap.cc
@@ -6,6 +6,7 @@
 #include "util-inl.h"
 #include "node.h"
 #include "handle_wrap.h"
+#include "string_bytes.h"
 
 #include <stdlib.h>
 
@@ -41,6 +42,7 @@ class FSEventWrap: public HandleWrap {
 
   uv_fs_event_t handle_;
   bool initialized_;
+  enum encoding encoding_;
 };
 
 
@@ -86,16 +88,20 @@ void FSEventWrap::Start(const FunctionCallbackInfo<Value>& args) {
 
   FSEventWrap* wrap = Unwrap<FSEventWrap>(args.Holder());
 
-  if (args.Length() < 1 || !args[0]->IsString()) {
-    return env->ThrowTypeError("filename must be a valid string");
-  }
+  static const char kErrMsg[] = "filename must be a string or Buffer";
+  if (args.Length() < 1)
+    return env->ThrowTypeError(kErrMsg);
 
-  node::Utf8Value path(env->isolate(), args[0]);
+  BufferValue path(env->isolate(), args[0]);
+  if (*path == nullptr)
+    return env->ThrowTypeError(kErrMsg);
 
   unsigned int flags = 0;
   if (args[2]->IsTrue())
     flags |= UV_FS_EVENT_RECURSIVE;
 
+  wrap->encoding_ = ParseEncoding(env->isolate(), args[3], UTF8);
+
   int err = uv_fs_event_init(wrap->env()->event_loop(), &wrap->handle_);
   if (err == 0) {
     wrap->initialized_ = true;
@@ -156,7 +162,18 @@ void FSEventWrap::OnEvent(uv_fs_event_t* handle, const char* filename,
   };
 
   if (filename != nullptr) {
-    argv[2] = OneByteString(env->isolate(), filename);
+    Local<Value> fn = StringBytes::Encode(env->isolate(),
+                                          filename,
+                                          wrap->encoding_);
+    if (fn.IsEmpty()) {
+      argv[0] = Integer::New(env->isolate(), UV_EINVAL);
+      argv[2] = StringBytes::Encode(env->isolate(),
+                                    filename,
+                                    strlen(filename),
+                                    BUFFER);
+    } else {
+      argv[2] = fn;
+    }
   }
 
   wrap->MakeCallback(env->onchange_string(), ARRAY_SIZE(argv), argv);