Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

8 files changed, 2540 insertions, 0 deletions

diff --git a/third_party/rust/winreg/src/decoder/mod.rs b/third_party/rust/winreg/src/decoder/mod.rs
new file mode 100644
index 0000000000..82493b846d
--- /dev/null
+++ b/third_party/rust/winreg/src/decoder/mod.rs
@@ -0,0 +1,101 @@
+// Copyright 2017, Igor Shaula
+// Licensed under the MIT License <LICENSE or
+// http://opensource.org/licenses/MIT>. This file
+// may not be copied, modified, or distributed
+// except according to those terms.
+use super::enums::*;
+use super::RegKey;
+use std::error::Error;
+use std::fmt;
+use std::io;
+use winapi::shared::minwindef::DWORD;
+
+macro_rules! read_value {
+    ($s:ident) => {
+        match mem::replace(&mut $s.f_name, None) {
+            Some(ref s) => $s.key.get_value(s).map_err(DecoderError::IoError),
+            None => Err(DecoderError::NoFieldName),
+        }
+    };
+}
+
+macro_rules! parse_string {
+    ($s:ident) => {{
+        let s: String = read_value!($s)?;
+        s.parse()
+            .map_err(|e| DecoderError::ParseError(format!("{:?}", e)))
+    }};
+}
+
+macro_rules! no_impl {
+    ($e:expr) => {
+        Err(DecoderError::DecodeNotImplemented($e.to_owned()))
+    };
+}
+
+#[cfg(feature = "serialization-serde")]
+mod serialization_serde;
+
+#[derive(Debug)]
+pub enum DecoderError {
+    DecodeNotImplemented(String),
+    DeserializerError(String),
+    IoError(io::Error),
+    ParseError(String),
+    NoFieldName,
+}
+
+impl fmt::Display for DecoderError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{:?}", self)
+    }
+}
+
+impl Error for DecoderError {}
+
+impl From<io::Error> for DecoderError {
+    fn from(err: io::Error) -> DecoderError {
+        DecoderError::IoError(err)
+    }
+}
+
+pub type DecodeResult<T> = Result<T, DecoderError>;
+
+#[derive(Debug)]
+enum DecoderReadingState {
+    WaitingForKey,
+    WaitingForValue,
+}
+
+#[derive(Debug)]
+enum DecoderEnumerationState {
+    EnumeratingKeys(DWORD),
+    EnumeratingValues(DWORD),
+}
+
+#[derive(Debug)]
+pub struct Decoder {
+    key: RegKey,
+    f_name: Option<String>,
+    reading_state: DecoderReadingState,
+    enumeration_state: DecoderEnumerationState,
+}
+
+const DECODER_SAM: DWORD = KEY_QUERY_VALUE | KEY_ENUMERATE_SUB_KEYS;
+
+impl Decoder {
+    pub fn from_key(key: &RegKey) -> DecodeResult<Decoder> {
+        key.open_subkey_with_flags("", DECODER_SAM)
+            .map(Decoder::new)
+            .map_err(DecoderError::IoError)
+    }
+
+    fn new(key: RegKey) -> Decoder {
+        Decoder {
+            key,
+            f_name: None,
+            reading_state: DecoderReadingState::WaitingForKey,
+            enumeration_state: DecoderEnumerationState::EnumeratingKeys(0),
+        }
+    }
+}
diff --git a/third_party/rust/winreg/src/decoder/serialization_serde.rs b/third_party/rust/winreg/src/decoder/serialization_serde.rs
new file mode 100644
index 0000000000..1287540448
--- /dev/null
+++ b/third_party/rust/winreg/src/decoder/serialization_serde.rs
@@ -0,0 +1,331 @@
+// Copyright 2017, Igor Shaula
+// Licensed under the MIT License <LICENSE or
+// http://opensource.org/licenses/MIT>. This file
+// may not be copied, modified, or distributed
+// except according to those terms.
+use super::super::FromRegValue;
+use super::{
+    DecodeResult, Decoder, DecoderEnumerationState, DecoderError, DecoderReadingState, DECODER_SAM,
+};
+use serde::de::*;
+use std::fmt;
+use std::mem;
+
+impl Error for DecoderError {
+    fn custom<T: fmt::Display>(msg: T) -> Self {
+        DecoderError::DeserializerError(format!("{}", msg))
+    }
+}
+
+impl<'de, 'a> Deserializer<'de> for &'a mut Decoder {
+    type Error = DecoderError;
+    fn deserialize_any<V>(self, visitor: V) -> DecodeResult<V::Value>
+    where
+        V: Visitor<'de>,
+    {
+        use self::DecoderEnumerationState::*;
+        match self.enumeration_state {
+            EnumeratingKeys(..) => no_impl!("deserialize_any for keys"),
+            EnumeratingValues(..) => {
+                let s = self.f_name.as_ref().ok_or(DecoderError::NoFieldName)?;
+                let v = self.key.get_raw_value(s)?;
+                use RegType::*;
+                match v.vtype {
+                    REG_SZ | REG_EXPAND_SZ | REG_MULTI_SZ => {
+                        visitor.visit_string(String::from_reg_value(&v)?)
+                    }
+                    REG_DWORD => visitor.visit_u32(u32::from_reg_value(&v)?),
+                    REG_QWORD => visitor.visit_u64(u64::from_reg_value(&v)?),
+                    _ => Err(DecoderError::DecodeNotImplemented(
+                        "value type deserialization not implemented".to_owned(),
+                    )),
+                }
+            }
+        }
+    }
+
+    fn deserialize_bool<V>(self, visitor: V) -> DecodeResult<V::Value>
+    where
+        V: Visitor<'de>,
+    {
+        visitor.visit_bool(read_value!(self).map(|v: u32| v > 0)?)
+    }
+
+    fn deserialize_u8<V>(self, visitor: V) -> DecodeResult<V::Value>
+    where
+        V: Visitor<'de>,
+    {
+        self.deserialize_u32(visitor)
+    }
+
+    fn deserialize_u16<V>(self, visitor: V) -> DecodeResult<V::Value>
+    where
+        V: Visitor<'de>,
+    {
+        self.deserialize_u32(visitor)
+    }
+
+    fn deserialize_u32<V>(self, visitor: V) -> DecodeResult<V::Value>
+    where
+        V: Visitor<'de>,
+    {
+        visitor.visit_u32(read_value!(self)?)
+    }
+
+    fn deserialize_u64<V>(self, visitor: V) -> DecodeResult<V::Value>
+    where
+        V: Visitor<'de>,
+    {
+        visitor.visit_u64(read_value!(self)?)
+    }
+
+    fn deserialize_i8<V>(self, visitor: V) -> DecodeResult<V::Value>
+    where
+        V: Visitor<'de>,
+    {
+        visitor.visit_i8(parse_string!(self)?)
+    }
+
+    fn deserialize_i16<V>(self, visitor: V) -> DecodeResult<V::Value>
+    where
+        V: Visitor<'de>,
+    {
+        visitor.visit_i16(parse_string!(self)?)
+    }
+
+    fn deserialize_i32<V>(self, visitor: V) -> DecodeResult<V::Value>
+    where
+        V: Visitor<'de>,
+    {
+        visitor.visit_i32(parse_string!(self)?)
+    }
+
+    fn deserialize_i64<V>(self, visitor: V) -> DecodeResult<V::Value>
+    where
+        V: Visitor<'de>,
+    {
+        visitor.visit_i64(parse_string!(self)?)
+    }
+
+    fn deserialize_f32<V>(self, visitor: V) -> DecodeResult<V::Value>
+    where
+        V: Visitor<'de>,
+    {
+        visitor.visit_f32(parse_string!(self)?)
+    }
+
+    fn deserialize_f64<V>(self, visitor: V) -> DecodeResult<V::Value>
+    where
+        V: Visitor<'de>,
+    {
+        visitor.visit_f64(parse_string!(self)?)
+    }
+
+    fn deserialize_char<V>(self, visitor: V) -> DecodeResult<V::Value>
+    where
+        V: Visitor<'de>,
+    {
+        self.deserialize_string(visitor)
+    }
+
+    fn deserialize_str<V>(self, _visitor: V) -> DecodeResult<V::Value>
+    where
+        V: Visitor<'de>,
+    {
+        no_impl!("deserialize_str")
+    }
+
+    fn deserialize_string<V>(self, visitor: V) -> DecodeResult<V::Value>
+    where
+        V: Visitor<'de>,
+    {
+        use self::DecoderReadingState::*;
+        match self.reading_state {
+            WaitingForKey => {
+                let s = self.f_name.as_ref().ok_or(DecoderError::NoFieldName)?;
+                visitor.visit_string(s.clone())
+            }
+            WaitingForValue => visitor.visit_string(read_value!(self)?),
+        }
+    }
+
+    fn deserialize_bytes<V>(self, _visitor: V) -> DecodeResult<V::Value>
+    where
+        V: Visitor<'de>,
+    {
+        no_impl!("deserialize_bytes")
+    }
+
+    fn deserialize_byte_buf<V>(self, _visitor: V) -> DecodeResult<V::Value>
+    where
+        V: Visitor<'de>,
+    {
+        no_impl!("deserialize_byte_buf")
+    }
+
+    fn deserialize_option<V>(self, visitor: V) -> DecodeResult<V::Value>
+    where
+        V: Visitor<'de>,
+    {
+        let v = {
+            let s = self.f_name.as_ref().ok_or(DecoderError::NoFieldName)?;
+            self.key.get_raw_value(s)
+        };
+        match v {
+            Ok(..) => visitor.visit_some(&mut *self),
+            Err(..) => visitor.visit_none(),
+        }
+    }
+
+    fn deserialize_unit<V>(self, _visitor: V) -> DecodeResult<V::Value>
+    where
+        V: Visitor<'de>,
+    {
+        no_impl!("deserialize_unit")
+    }
+
+    fn deserialize_unit_struct<V>(self, _name: &'static str, _visitor: V) -> DecodeResult<V::Value>
+    where
+        V: Visitor<'de>,
+    {
+        no_impl!("deserialize_unit_struct")
+    }
+
+    fn deserialize_newtype_struct<V>(
+        self,
+        _name: &'static str,
+        _visitor: V,
+    ) -> DecodeResult<V::Value>
+    where
+        V: Visitor<'de>,
+    {
+        no_impl!("deserialize_newtype_struct")
+    }
+
+    fn deserialize_seq<V>(self, _visitor: V) -> DecodeResult<V::Value>
+    where
+        V: Visitor<'de>,
+    {
+        no_impl!("deserialize_seq")
+    }
+
+    fn deserialize_tuple<V>(self, _len: usize, _visitor: V) -> DecodeResult<V::Value>
+    where
+        V: Visitor<'de>,
+    {
+        no_impl!("deserialize_tuple")
+    }
+
+    fn deserialize_tuple_struct<V>(
+        self,
+        _name: &'static str,
+        _len: usize,
+        _visitor: V,
+    ) -> DecodeResult<V::Value>
+    where
+        V: Visitor<'de>,
+    {
+        no_impl!("deserialize_tuple_struct")
+    }
+
+    fn deserialize_map<V>(self, visitor: V) -> DecodeResult<V::Value>
+    where
+        V: Visitor<'de>,
+    {
+        visitor.visit_map(self)
+    }
+
+    fn deserialize_struct<V>(
+        self,
+        _name: &'static str,
+        _fields: &'static [&'static str],
+        visitor: V,
+    ) -> DecodeResult<V::Value>
+    where
+        V: Visitor<'de>,
+    {
+        visitor.visit_map(self)
+    }
+
+    fn deserialize_identifier<V>(self, visitor: V) -> DecodeResult<V::Value>
+    where
+        V: Visitor<'de>,
+    {
+        self.deserialize_string(visitor)
+    }
+
+    fn deserialize_enum<V>(
+        self,
+        _name: &'static str,
+        _variants: &'static [&'static str],
+        _visitor: V,
+    ) -> DecodeResult<V::Value>
+    where
+        V: Visitor<'de>,
+    {
+        no_impl!("deserialize_enum")
+    }
+
+    fn deserialize_ignored_any<V>(self, visitor: V) -> DecodeResult<V::Value>
+    where
+        V: Visitor<'de>,
+    {
+        self.deserialize_any(visitor)
+    }
+}
+
+impl<'de, 'a> MapAccess<'de> for Decoder {
+    type Error = DecoderError;
+    fn next_key_seed<K>(&mut self, seed: K) -> Result<Option<K::Value>, Self::Error>
+    where
+        K: DeserializeSeed<'de>,
+    {
+        self.reading_state = DecoderReadingState::WaitingForKey;
+        use self::DecoderEnumerationState::*;
+        match self.enumeration_state {
+            EnumeratingKeys(index) => match self.key.enum_key(index) {
+                Some(res) => {
+                    self.f_name = Some(res?);
+                    self.enumeration_state = EnumeratingKeys(index + 1);
+                    seed.deserialize(&mut *self).map(Some)
+                }
+                None => {
+                    self.enumeration_state = EnumeratingValues(0);
+                    self.next_key_seed(seed)
+                }
+            },
+            EnumeratingValues(index) => {
+                let next_value = self.key.enum_value(index);
+                match next_value {
+                    Some(res) => {
+                        self.f_name = Some(res?.0);
+                        self.enumeration_state = EnumeratingValues(index + 1);
+                        seed.deserialize(&mut *self).map(Some)
+                    }
+                    None => Ok(None),
+                }
+            }
+        }
+    }
+
+    fn next_value_seed<V>(&mut self, seed: V) -> Result<V::Value, Self::Error>
+    where
+        V: DeserializeSeed<'de>,
+    {
+        self.reading_state = DecoderReadingState::WaitingForValue;
+        use self::DecoderEnumerationState::*;
+        match self.enumeration_state {
+            EnumeratingKeys(..) => {
+                let f_name = self.f_name.as_ref().ok_or(DecoderError::NoFieldName)?;
+                match self.key.open_subkey_with_flags(f_name, DECODER_SAM) {
+                    Ok(subkey) => {
+                        let mut nested = Decoder::new(subkey);
+                        seed.deserialize(&mut nested)
+                    }
+                    Err(err) => Err(DecoderError::IoError(err)),
+                }
+            }
+            EnumeratingValues(..) => seed.deserialize(&mut *self),
+        }
+    }
+}
diff --git a/third_party/rust/winreg/src/encoder/mod.rs b/third_party/rust/winreg/src/encoder/mod.rs
new file mode 100644
index 0000000000..f552dc05df
--- /dev/null
+++ b/third_party/rust/winreg/src/encoder/mod.rs
@@ -0,0 +1,97 @@
+// Copyright 2017, Igor Shaula
+// Licensed under the MIT License <LICENSE or
+// http://opensource.org/licenses/MIT>. This file
+// may not be copied, modified, or distributed
+// except according to those terms.
+use self::EncoderState::*;
+use super::enums::*;
+use super::transaction::Transaction;
+use super::RegKey;
+use std::error::Error;
+use std::fmt;
+use std::io;
+use winapi::shared::minwindef::DWORD;
+
+macro_rules! emit_value {
+    ($s:ident, $v:ident) => {
+        match mem::replace(&mut $s.state, Start) {
+            NextKey(ref s) => $s.keys[$s.keys.len() - 1]
+                .set_value(s, &$v)
+                .map_err(EncoderError::IoError),
+            Start => Err(EncoderError::NoFieldName),
+        }
+    };
+}
+
+macro_rules! no_impl {
+    ($e:expr) => {
+        Err(EncoderError::EncodeNotImplemented($e.to_owned()))
+    };
+}
+
+#[cfg(feature = "serialization-serde")]
+mod serialization_serde;
+
+#[derive(Debug)]
+pub enum EncoderError {
+    EncodeNotImplemented(String),
+    SerializerError(String),
+    IoError(io::Error),
+    NoFieldName,
+    KeyMustBeAString,
+}
+
+impl fmt::Display for EncoderError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{:?}", self)
+    }
+}
+
+impl Error for EncoderError {}
+
+pub type EncodeResult<T> = Result<T, EncoderError>;
+
+impl From<io::Error> for EncoderError {
+    fn from(err: io::Error) -> EncoderError {
+        EncoderError::IoError(err)
+    }
+}
+
+#[derive(Debug)]
+enum EncoderState {
+    Start,
+    NextKey(String),
+    // NextMapKey,
+}
+
+#[derive(Debug)]
+pub struct Encoder {
+    keys: Vec<RegKey>,
+    tr: Transaction,
+    state: EncoderState,
+}
+
+const ENCODER_SAM: DWORD = KEY_CREATE_SUB_KEY | KEY_SET_VALUE;
+
+impl Encoder {
+    pub fn from_key(key: &RegKey) -> EncodeResult<Encoder> {
+        let tr = Transaction::new()?;
+        key.open_subkey_transacted_with_flags("", &tr, ENCODER_SAM)
+            .map(|k| Encoder::new(k, tr))
+            .map_err(EncoderError::IoError)
+    }
+
+    fn new(key: RegKey, tr: Transaction) -> Encoder {
+        let mut keys = Vec::with_capacity(5);
+        keys.push(key);
+        Encoder {
+            keys,
+            tr,
+            state: Start,
+        }
+    }
+
+    pub fn commit(&mut self) -> EncodeResult<()> {
+        self.tr.commit().map_err(EncoderError::IoError)
+    }
+}
diff --git a/third_party/rust/winreg/src/encoder/serialization_serde.rs b/third_party/rust/winreg/src/encoder/serialization_serde.rs
new file mode 100644
index 0000000000..f764cce6ec
--- /dev/null
+++ b/third_party/rust/winreg/src/encoder/serialization_serde.rs
@@ -0,0 +1,513 @@
+// Copyright 2017, Igor Shaula
+// Licensed under the MIT License <LICENSE or
+// http://opensource.org/licenses/MIT>. This file
+// may not be copied, modified, or distributed
+// except according to those terms.
+use super::EncoderState::*;
+use super::{EncodeResult, Encoder, EncoderError, ENCODER_SAM};
+use serde::ser::*;
+use std::fmt;
+use std::mem;
+
+impl Error for EncoderError {
+    fn custom<T: fmt::Display>(msg: T) -> Self {
+        EncoderError::SerializerError(format!("{}", msg))
+    }
+}
+
+impl<'a> Serializer for &'a mut Encoder {
+    type Ok = ();
+    type Error = EncoderError;
+
+    type SerializeSeq = SeqEncoder;
+    type SerializeTuple = TupleEncoder;
+    type SerializeTupleStruct = TupleStructEncoder;
+    type SerializeTupleVariant = TupleVariantEncoder;
+    type SerializeMap = StructMapEncoder<'a>;
+    type SerializeStruct = StructMapEncoder<'a>;
+    type SerializeStructVariant = StructVariantEncoder;
+
+    fn serialize_bool(self, value: bool) -> EncodeResult<Self::Ok> {
+        self.serialize_u32(value as u32)
+    }
+
+    fn serialize_i8(self, value: i8) -> EncodeResult<Self::Ok> {
+        self.serialize_i64(value as i64)
+    }
+
+    fn serialize_i16(self, value: i16) -> EncodeResult<Self::Ok> {
+        self.serialize_i64(value as i64)
+    }
+
+    fn serialize_i32(self, value: i32) -> EncodeResult<Self::Ok> {
+        self.serialize_i64(value as i64)
+    }
+
+    fn serialize_i64(self, value: i64) -> EncodeResult<Self::Ok> {
+        let s = value.to_string();
+        emit_value!(self, s)
+    }
+
+    fn serialize_u8(self, value: u8) -> EncodeResult<Self::Ok> {
+        self.serialize_u32(value as u32)
+    }
+
+    fn serialize_u16(self, value: u16) -> EncodeResult<Self::Ok> {
+        self.serialize_u32(value as u32)
+    }
+
+    fn serialize_u32(self, value: u32) -> EncodeResult<Self::Ok> {
+        emit_value!(self, value)
+    }
+
+    fn serialize_u64(self, value: u64) -> EncodeResult<Self::Ok> {
+        emit_value!(self, value)
+    }
+
+    fn serialize_f32(self, value: f32) -> EncodeResult<Self::Ok> {
+        let s = value.to_string();
+        emit_value!(self, s)
+    }
+
+    fn serialize_f64(self, value: f64) -> EncodeResult<Self::Ok> {
+        let s = value.to_string();
+        emit_value!(self, s)
+    }
+
+    fn serialize_char(self, value: char) -> EncodeResult<Self::Ok> {
+        let mut s = String::new();
+        s.push(value);
+        emit_value!(self, s)
+    }
+
+    fn serialize_str(self, value: &str) -> EncodeResult<Self::Ok> {
+        emit_value!(self, value)
+    }
+
+    fn serialize_bytes(self, _value: &[u8]) -> EncodeResult<Self::Ok> {
+        no_impl!("serialize_bytes")
+    }
+
+    fn serialize_none(self) -> EncodeResult<Self::Ok> {
+        no_impl!("serialize_none")
+    }
+
+    fn serialize_some<T: ?Sized + Serialize>(self, _value: &T) -> EncodeResult<Self::Ok> {
+        no_impl!("serialize_some")
+    }
+
+    fn serialize_unit(self) -> EncodeResult<Self::Ok> {
+        no_impl!("serialize_unit")
+    }
+
+    fn serialize_unit_struct(self, _name: &'static str) -> EncodeResult<Self::Ok> {
+        no_impl!("serialize_unit_struct")
+    }
+
+    fn serialize_unit_variant(
+        self,
+        _name: &'static str,
+        _variant_index: u32,
+        _variant: &'static str,
+    ) -> EncodeResult<Self::Ok> {
+        no_impl!("serialize_unit_variant")
+    }
+
+    fn serialize_newtype_struct<T: ?Sized + Serialize>(
+        self,
+        _name: &'static str,
+        _value: &T,
+    ) -> EncodeResult<Self::Ok> {
+        no_impl!("serialize_newtype_struct")
+    }
+
+    fn serialize_newtype_variant<T: ?Sized + Serialize>(
+        self,
+        _name: &'static str,
+        _variant_index: u32,
+        _variant: &'static str,
+        _value: &T,
+    ) -> EncodeResult<Self::Ok> {
+        no_impl!("serialize_newtype_variant")
+    }
+
+    fn serialize_seq(self, _len: Option<usize>) -> EncodeResult<Self::SerializeSeq> {
+        no_impl!("serialize_seq")
+    }
+
+    fn serialize_tuple(self, _len: usize) -> EncodeResult<Self::SerializeTuple> {
+        no_impl!("serialize_tuple")
+    }
+
+    fn serialize_tuple_struct(
+        self,
+        _name: &'static str,
+        _len: usize,
+    ) -> EncodeResult<Self::SerializeTupleStruct> {
+        no_impl!("serialize_tuple_struct")
+    }
+
+    fn serialize_tuple_variant(
+        self,
+        _name: &'static str,
+        _variant_index: u32,
+        _variant: &'static str,
+        _len: usize,
+    ) -> EncodeResult<Self::SerializeTupleVariant> {
+        no_impl!("serialize_tuple_variant")
+    }
+
+    fn serialize_map(self, _len: Option<usize>) -> EncodeResult<Self::SerializeMap> {
+        match mem::replace(&mut self.state, Start) {
+            // ---
+            Start => {
+                // root structure
+                Ok(StructMapEncoder {
+                    enc: self,
+                    is_root: true,
+                })
+            }
+            NextKey(ref s) => {
+                // nested structure
+                match self.keys[self.keys.len() - 1].create_subkey_transacted_with_flags(
+                    &s,
+                    &self.tr,
+                    ENCODER_SAM,
+                ) {
+                    Ok((subkey, _disp)) => {
+                        self.keys.push(subkey);
+                        Ok(StructMapEncoder {
+                            enc: self,
+                            is_root: true,
+                        })
+                    }
+                    Err(err) => Err(EncoderError::IoError(err)),
+                }
+            }
+        }
+    }
+
+    fn serialize_struct(
+        self,
+        _name: &'static str,
+        _len: usize,
+    ) -> EncodeResult<Self::SerializeStruct> {
+        self.serialize_map(Some(_len))
+    }
+
+    fn serialize_struct_variant(
+        self,
+        _name: &'static str,
+        _variant_index: u32,
+        _variant: &'static str,
+        _len: usize,
+    ) -> EncodeResult<Self::SerializeStructVariant> {
+        no_impl!("serialize_struct_variant")
+    }
+}
+
+pub struct SeqEncoder {}
+
+impl SerializeSeq for SeqEncoder {
+    type Ok = ();
+    type Error = EncoderError;
+    fn serialize_element<T: ?Sized + Serialize>(&mut self, _value: &T) -> EncodeResult<Self::Ok> {
+        no_impl!("SerializeSeq::serialize_element")
+    }
+    fn end(self) -> EncodeResult<Self::Ok> {
+        no_impl!("SerializeSeq::end")
+    }
+}
+
+pub struct TupleEncoder {}
+
+impl SerializeTuple for TupleEncoder {
+    type Ok = ();
+    type Error = EncoderError;
+
+    fn serialize_element<T: ?Sized + Serialize>(&mut self, _value: &T) -> EncodeResult<Self::Ok> {
+        no_impl!("SerializeTuple::serialize_element")
+    }
+
+    fn end(self) -> EncodeResult<Self::Ok> {
+        no_impl!("SerializeTuple::end")
+    }
+}
+
+pub struct TupleStructEncoder {}
+
+impl SerializeTupleStruct for TupleStructEncoder {
+    type Ok = ();
+    type Error = EncoderError;
+
+    fn serialize_field<T: ?Sized + Serialize>(&mut self, _value: &T) -> EncodeResult<Self::Ok> {
+        no_impl!("SerializeTupleStruct::serialize_field")
+    }
+
+    fn end(self) -> EncodeResult<Self::Ok> {
+        no_impl!("SerializeTupleStruct::end")
+    }
+}
+
+pub struct TupleVariantEncoder {}
+
+impl SerializeTupleVariant for TupleVariantEncoder {
+    type Ok = ();
+    type Error = EncoderError;
+
+    fn serialize_field<T: ?Sized + Serialize>(&mut self, _value: &T) -> EncodeResult<Self::Ok> {
+        no_impl!("SerializeTupleVariant::serialize_field")
+    }
+
+    fn end(self) -> EncodeResult<Self::Ok> {
+        no_impl!("SerializeTupleVariant::end")
+    }
+}
+
+struct MapKeySerializer;
+
+impl serde::Serializer for MapKeySerializer {
+    type Ok = String;
+    type Error = EncoderError;
+
+    type SerializeSeq = Impossible<String, EncoderError>;
+    type SerializeTuple = Impossible<String, EncoderError>;
+    type SerializeTupleStruct = Impossible<String, EncoderError>;
+    type SerializeTupleVariant = Impossible<String, EncoderError>;
+    type SerializeMap = Impossible<String, EncoderError>;
+    type SerializeStruct = Impossible<String, EncoderError>;
+    type SerializeStructVariant = Impossible<String, EncoderError>;
+
+    #[inline]
+    fn serialize_unit_variant(
+        self,
+        _name: &'static str,
+        _variant_index: u32,
+        variant: &'static str,
+    ) -> EncodeResult<Self::Ok> {
+        Ok(variant.to_owned())
+    }
+
+    #[inline]
+    fn serialize_newtype_struct<T>(self, _name: &'static str, value: &T) -> EncodeResult<Self::Ok>
+    where
+        T: ?Sized + Serialize,
+    {
+        value.serialize(self)
+    }
+
+    fn serialize_bool(self, _value: bool) -> EncodeResult<Self::Ok> {
+        Err(EncoderError::KeyMustBeAString)
+    }
+
+    fn serialize_i8(self, value: i8) -> EncodeResult<Self::Ok> {
+        Ok(value.to_string())
+    }
+
+    fn serialize_i16(self, value: i16) -> EncodeResult<Self::Ok> {
+        Ok(value.to_string())
+    }
+
+    fn serialize_i32(self, value: i32) -> EncodeResult<Self::Ok> {
+        Ok(value.to_string())
+    }
+
+    fn serialize_i64(self, value: i64) -> EncodeResult<Self::Ok> {
+        Ok(value.to_string())
+    }
+
+    fn serialize_u8(self, value: u8) -> EncodeResult<Self::Ok> {
+        Ok(value.to_string())
+    }
+
+    fn serialize_u16(self, value: u16) -> EncodeResult<Self::Ok> {
+        Ok(value.to_string())
+    }
+
+    fn serialize_u32(self, value: u32) -> EncodeResult<Self::Ok> {
+        Ok(value.to_string())
+    }
+
+    fn serialize_u64(self, value: u64) -> EncodeResult<Self::Ok> {
+        Ok(value.to_string())
+    }
+
+    fn serialize_f32(self, _value: f32) -> EncodeResult<Self::Ok> {
+        Err(EncoderError::KeyMustBeAString)
+    }
+
+    fn serialize_f64(self, _value: f64) -> EncodeResult<Self::Ok> {
+        Err(EncoderError::KeyMustBeAString)
+    }
+
+    #[inline]
+    fn serialize_char(self, value: char) -> EncodeResult<Self::Ok> {
+        Ok({
+            let mut s = String::new();
+            s.push(value);
+            s
+        })
+    }
+
+    #[inline]
+    fn serialize_str(self, value: &str) -> EncodeResult<Self::Ok> {
+        Ok(value.to_owned())
+    }
+
+    fn serialize_bytes(self, _value: &[u8]) -> EncodeResult<Self::Ok> {
+        Err(EncoderError::KeyMustBeAString)
+    }
+
+    fn serialize_unit(self) -> EncodeResult<Self::Ok> {
+        Err(EncoderError::KeyMustBeAString)
+    }
+
+    fn serialize_unit_struct(self, _name: &'static str) -> EncodeResult<Self::Ok> {
+        Err(EncoderError::KeyMustBeAString)
+    }
+
+    fn serialize_newtype_variant<T>(
+        self,
+        _name: &'static str,
+        _variant_index: u32,
+        _variant: &'static str,
+        _value: &T,
+    ) -> EncodeResult<Self::Ok>
+    where
+        T: ?Sized + Serialize,
+    {
+        Err(EncoderError::KeyMustBeAString)
+    }
+
+    fn serialize_none(self) -> EncodeResult<Self::Ok> {
+        Err(EncoderError::KeyMustBeAString)
+    }
+
+    fn serialize_some<T>(self, _value: &T) -> EncodeResult<Self::Ok>
+    where
+        T: ?Sized + Serialize,
+    {
+        Err(EncoderError::KeyMustBeAString)
+    }
+
+    fn serialize_seq(self, _len: Option<usize>) -> EncodeResult<Self::SerializeSeq> {
+        Err(EncoderError::KeyMustBeAString)
+    }
+
+    fn serialize_tuple(self, _len: usize) -> EncodeResult<Self::SerializeTuple> {
+        Err(EncoderError::KeyMustBeAString)
+    }
+
+    fn serialize_tuple_struct(
+        self,
+        _name: &'static str,
+        _len: usize,
+    ) -> EncodeResult<Self::SerializeTupleStruct> {
+        Err(EncoderError::KeyMustBeAString)
+    }
+
+    fn serialize_tuple_variant(
+        self,
+        _name: &'static str,
+        _variant_index: u32,
+        _variant: &'static str,
+        _len: usize,
+    ) -> EncodeResult<Self::SerializeTupleVariant> {
+        Err(EncoderError::KeyMustBeAString)
+    }
+
+    fn serialize_map(self, _len: Option<usize>) -> EncodeResult<Self::SerializeMap> {
+        Err(EncoderError::KeyMustBeAString)
+    }
+
+    fn serialize_struct(
+        self,
+        _name: &'static str,
+        _len: usize,
+    ) -> EncodeResult<Self::SerializeStruct> {
+        Err(EncoderError::KeyMustBeAString)
+    }
+
+    fn serialize_struct_variant(
+        self,
+        _name: &'static str,
+        _variant_index: u32,
+        _variant: &'static str,
+        _len: usize,
+    ) -> EncodeResult<Self::SerializeStructVariant> {
+        Err(EncoderError::KeyMustBeAString)
+    }
+
+    fn collect_str<T: ?Sized>(self, value: &T) -> EncodeResult<String>
+    where
+        T: fmt::Display,
+    {
+        Ok(value.to_string())
+    }
+}
+
+pub struct StructMapEncoder<'a> {
+    enc: &'a mut Encoder,
+    is_root: bool,
+}
+
+impl<'a> SerializeStruct for StructMapEncoder<'a> {
+    type Ok = ();
+    type Error = EncoderError;
+
+    fn serialize_field<T: ?Sized + Serialize>(
+        &mut self,
+        key: &'static str,
+        value: &T,
+    ) -> EncodeResult<Self::Ok> {
+        self.enc.state = NextKey(String::from(key));
+        value.serialize(&mut *self.enc)
+    }
+
+    fn end(self) -> EncodeResult<Self::Ok> {
+        if self.is_root {
+            self.enc.keys.pop();
+        }
+        Ok(())
+    }
+}
+
+impl<'a> SerializeMap for StructMapEncoder<'a> {
+    type Ok = ();
+    type Error = EncoderError;
+
+    fn serialize_key<T: ?Sized + Serialize>(&mut self, key: &T) -> EncodeResult<Self::Ok> {
+        self.enc.state = NextKey(key.serialize(MapKeySerializer)?);
+        Ok(())
+    }
+
+    fn serialize_value<T: ?Sized + Serialize>(&mut self, value: &T) -> EncodeResult<Self::Ok> {
+        value.serialize(&mut *self.enc)
+    }
+
+    fn end(self) -> EncodeResult<Self::Ok> {
+        if self.is_root {
+            self.enc.keys.pop();
+        }
+        Ok(())
+    }
+}
+
+pub struct StructVariantEncoder {}
+
+impl SerializeStructVariant for StructVariantEncoder {
+    type Ok = ();
+    type Error = EncoderError;
+
+    fn serialize_field<T: ?Sized + Serialize>(
+        &mut self,
+        _key: &'static str,
+        _value: &T,
+    ) -> EncodeResult<Self::Ok> {
+        no_impl!("SerializeStructVariant::serialize_field")
+    }
+
+    fn end(self) -> EncodeResult<Self::Ok> {
+        no_impl!("SerializeStructVariant::end")
+    }
+}
diff --git a/third_party/rust/winreg/src/enums.rs b/third_party/rust/winreg/src/enums.rs
new file mode 100644
index 0000000000..b537b287c2
--- /dev/null
+++ b/third_party/rust/winreg/src/enums.rs
@@ -0,0 +1,51 @@
+// Copyright 2015, Igor Shaula
+// Licensed under the MIT License <LICENSE or
+// http://opensource.org/licenses/MIT>. This file
+// may not be copied, modified, or distributed
+// except according to those terms.
+
+//! `use winreg::enums::*;` to import all needed enumerations and constants
+use super::winapi;
+pub use winapi::um::winnt::{
+    KEY_ALL_ACCESS, KEY_CREATE_LINK, KEY_CREATE_SUB_KEY, KEY_ENUMERATE_SUB_KEYS, KEY_EXECUTE,
+    KEY_NOTIFY, KEY_QUERY_VALUE, KEY_READ, KEY_SET_VALUE, KEY_WOW64_32KEY, KEY_WOW64_64KEY,
+    KEY_WOW64_RES, KEY_WRITE,
+};
+pub use winapi::um::winreg::{
+    HKEY_CLASSES_ROOT, HKEY_CURRENT_CONFIG, HKEY_CURRENT_USER, HKEY_CURRENT_USER_LOCAL_SETTINGS,
+    HKEY_DYN_DATA, HKEY_LOCAL_MACHINE, HKEY_PERFORMANCE_DATA, HKEY_PERFORMANCE_NLSTEXT,
+    HKEY_PERFORMANCE_TEXT, HKEY_USERS, REG_PROCESS_APPKEY,
+};
+
+macro_rules! winapi_enum{
+    ($t:ident, $doc:expr => [$($v:ident),*]) => (
+        #[doc=$doc]
+        #[allow(non_camel_case_types)]
+        #[derive(Debug,Clone,PartialEq)]
+        pub enum $t {
+            $( $v = winapi::um::winnt::$v as isize ),*
+        }
+    )
+}
+
+winapi_enum!(RegType, "Enumeration of possible registry value types" => [
+REG_NONE,
+REG_SZ,
+REG_EXPAND_SZ,
+REG_BINARY,
+REG_DWORD,
+REG_DWORD_BIG_ENDIAN,
+REG_LINK,
+REG_MULTI_SZ,
+REG_RESOURCE_LIST,
+REG_FULL_RESOURCE_DESCRIPTOR,
+REG_RESOURCE_REQUIREMENTS_LIST,
+REG_QWORD
+]);
+pub use self::RegType::*;
+
+winapi_enum!(RegDisposition, "Enumeration of possible disposition values" => [
+REG_CREATED_NEW_KEY,
+REG_OPENED_EXISTING_KEY
+]);
+pub use self::RegDisposition::*;
diff --git a/third_party/rust/winreg/src/lib.rs b/third_party/rust/winreg/src/lib.rs
new file mode 100644
index 0000000000..784976c5c8
--- /dev/null
+++ b/third_party/rust/winreg/src/lib.rs
@@ -0,0 +1,1143 @@
+// Copyright 2015, Igor Shaula
+// Licensed under the MIT License <LICENSE or
+// http://opensource.org/licenses/MIT>. This file
+// may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Crate for accessing MS Windows registry
+//!
+//!## Usage
+//!
+//!### Basic usage
+//!
+//!```toml,ignore
+//!# Cargo.toml
+//![dependencies]
+//!winreg = "0.10"
+//!```
+//!
+//!```no_run
+//!extern crate winreg;
+//!use std::io;
+//!use std::path::Path;
+//!use winreg::enums::*;
+//!use winreg::RegKey;
+//!
+//!fn main() -> io::Result<()> {
+//!    println!("Reading some system info...");
+//!    let hklm = RegKey::predef(HKEY_LOCAL_MACHINE);
+//!    let cur_ver = hklm.open_subkey("SOFTWARE\\Microsoft\\Windows\\CurrentVersion")?;
+//!    let pf: String = cur_ver.get_value("ProgramFilesDir")?;
+//!    let dp: String = cur_ver.get_value("DevicePath")?;
+//!    println!("ProgramFiles = {}\nDevicePath = {}", pf, dp);
+//!    let info = cur_ver.query_info()?;
+//!    println!("info = {:?}", info);
+//!    let mt = info.get_last_write_time_system();
+//!    println!(
+//!        "last_write_time as winapi::um::minwinbase::SYSTEMTIME = {}-{:02}-{:02} {:02}:{:02}:{:02}",
+//!        mt.wYear, mt.wMonth, mt.wDay, mt.wHour, mt.wMinute, mt.wSecond
+//!    );
+//!
+//!    // enable `chrono` feature on `winreg` to make this work
+//!    // println!(
+//!    //     "last_write_time as chrono::NaiveDateTime = {}",
+//!    //     info.get_last_write_time_chrono()
+//!    // );
+//!
+//!    println!("And now lets write something...");
+//!    let hkcu = RegKey::predef(HKEY_CURRENT_USER);
+//!    let path = Path::new("Software").join("WinregRsExample1");
+//!    let (key, disp) = hkcu.create_subkey(&path)?;
+//!
+//!    match disp {
+//!        REG_CREATED_NEW_KEY => println!("A new key has been created"),
+//!        REG_OPENED_EXISTING_KEY => println!("An existing key has been opened"),
+//!    }
+//!
+//!    key.set_value("TestSZ", &"written by Rust")?;
+//!    let sz_val: String = key.get_value("TestSZ")?;
+//!    key.delete_value("TestSZ")?;
+//!    println!("TestSZ = {}", sz_val);
+//!
+//!    key.set_value("TestMultiSZ", &vec!["written", "by", "Rust"])?;
+//!    let multi_sz_val: Vec<String> = key.get_value("TestMultiSZ")?;
+//!    key.delete_value("TestMultiSZ")?;
+//!    println!("TestMultiSZ = {:?}", multi_sz_val);
+//!
+//!    key.set_value("TestDWORD", &1234567890u32)?;
+//!    let dword_val: u32 = key.get_value("TestDWORD")?;
+//!    println!("TestDWORD = {}", dword_val);
+//!
+//!    key.set_value("TestQWORD", &1234567891011121314u64)?;
+//!    let qword_val: u64 = key.get_value("TestQWORD")?;
+//!    println!("TestQWORD = {}", qword_val);
+//!
+//!    key.create_subkey("sub\\key")?;
+//!    hkcu.delete_subkey_all(&path)?;
+//!
+//!    println!("Trying to open nonexistent key...");
+//!    hkcu.open_subkey(&path).unwrap_or_else(|e| match e.kind() {
+//!        io::ErrorKind::NotFound => panic!("Key doesn't exist"),
+//!        io::ErrorKind::PermissionDenied => panic!("Access denied"),
+//!        _ => panic!("{:?}", e),
+//!    });
+//!    Ok(())
+//!}
+//!```
+//!
+//!### Iterators
+//!
+//!```no_run
+//!extern crate winreg;
+//!use std::io;
+//!use winreg::RegKey;
+//!use winreg::enums::*;
+//!
+//!fn main() -> io::Result<()> {
+//!    println!("File extensions, registered in system:");
+//!    for i in RegKey::predef(HKEY_CLASSES_ROOT)
+//!        .enum_keys().map(|x| x.unwrap())
+//!        .filter(|x| x.starts_with("."))
+//!    {
+//!        println!("{}", i);
+//!    }
+//!
+//!    let system = RegKey::predef(HKEY_LOCAL_MACHINE)
+//!        .open_subkey("HARDWARE\\DESCRIPTION\\System")?;
+//!    for (name, value) in system.enum_values().map(|x| x.unwrap()) {
+//!        println!("{} = {:?}", name, value);
+//!    }
+//!
+//!    Ok(())
+//!}
+//!```
+//!
+#[cfg(feature = "chrono")]
+extern crate chrono;
+#[cfg(feature = "serialization-serde")]
+extern crate serde;
+extern crate winapi;
+use enums::*;
+use std::default::Default;
+use std::ffi::OsStr;
+use std::fmt;
+use std::io;
+use std::mem::transmute;
+use std::os::windows::ffi::OsStrExt;
+use std::ptr;
+use std::slice;
+#[cfg(feature = "transactions")]
+use transaction::Transaction;
+use types::{FromRegValue, ToRegValue};
+pub use winapi::shared::minwindef::HKEY;
+use winapi::shared::minwindef::{BYTE, DWORD, FILETIME, LPBYTE};
+use winapi::shared::winerror;
+use winapi::um::minwinbase::SYSTEMTIME;
+use winapi::um::timezoneapi::FileTimeToSystemTime;
+use winapi::um::winnt::{self, WCHAR};
+use winapi::um::winreg as winapi_reg;
+
+macro_rules! werr {
+    ($e:expr) => {
+        Err(io::Error::from_raw_os_error($e as i32))
+    };
+}
+
+#[cfg(feature = "serialization-serde")]
+mod decoder;
+#[cfg(feature = "serialization-serde")]
+mod encoder;
+pub mod enums;
+#[cfg(feature = "transactions")]
+pub mod transaction;
+pub mod types;
+
+/// Metadata returned by `RegKey::query_info`
+#[derive(Debug, Default)]
+pub struct RegKeyMetadata {
+    // pub Class: winapi::LPWSTR,
+    // pub ClassLen: DWORD,
+    pub sub_keys: DWORD,
+    pub max_sub_key_len: DWORD,
+    pub max_class_len: DWORD,
+    pub values: DWORD,
+    pub max_value_name_len: DWORD,
+    pub max_value_len: DWORD,
+    // pub SecurityDescriptor: DWORD,
+    pub last_write_time: FILETIME,
+}
+
+impl RegKeyMetadata {
+    /// Returns `last_write_time` field as `winapi::um::minwinbase::SYSTEMTIME`
+    pub fn get_last_write_time_system(&self) -> SYSTEMTIME {
+        let mut st: SYSTEMTIME = unsafe { ::std::mem::zeroed() };
+        unsafe {
+            FileTimeToSystemTime(&self.last_write_time, &mut st);
+        }
+        st
+    }
+
+    /// Returns `last_write_time` field as `chrono::NaiveDateTime`.
+    /// Part of `chrono` feature.
+    #[cfg(feature = "chrono")]
+    pub fn get_last_write_time_chrono(&self) -> chrono::NaiveDateTime {
+        let st = self.get_last_write_time_system();
+
+        chrono::NaiveDate::from_ymd(st.wYear.into(), st.wMonth.into(), st.wDay.into()).and_hms(
+            st.wHour.into(),
+            st.wMinute.into(),
+            st.wSecond.into(),
+        )
+    }
+}
+
+/// Raw registry value
+#[derive(PartialEq)]
+pub struct RegValue {
+    pub bytes: Vec<u8>,
+    pub vtype: RegType,
+}
+
+macro_rules! format_reg_value {
+    ($e:expr => $t:ident) => {
+        match $t::from_reg_value($e) {
+            Ok(val) => format!("{:?}", val),
+            Err(_) => return Err(fmt::Error),
+        }
+    };
+}
+
+impl fmt::Display for RegValue {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        let f_val = match self.vtype {
+            REG_SZ | REG_EXPAND_SZ | REG_MULTI_SZ => format_reg_value!(self => String),
+            REG_DWORD => format_reg_value!(self => u32),
+            REG_QWORD => format_reg_value!(self => u64),
+            _ => format!("{:?}", self.bytes), //TODO: implement more types
+        };
+        write!(f, "{}", f_val)
+    }
+}
+
+impl fmt::Debug for RegValue {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "RegValue({:?}: {})", self.vtype, self)
+    }
+}
+
+/// Handle of opened registry key
+#[derive(Debug)]
+pub struct RegKey {
+    hkey: HKEY,
+}
+
+unsafe impl Send for RegKey {}
+
+impl RegKey {
+    /// Open one of predefined keys:
+    ///
+    /// * `HKEY_CLASSES_ROOT`
+    /// * `HKEY_CURRENT_USER`
+    /// * `HKEY_LOCAL_MACHINE`
+    /// * `HKEY_USERS`
+    /// * `HKEY_PERFORMANCE_DATA`
+    /// * `HKEY_PERFORMANCE_TEXT`
+    /// * `HKEY_PERFORMANCE_NLSTEXT`
+    /// * `HKEY_CURRENT_CONFIG`
+    /// * `HKEY_DYN_DATA`
+    /// * `HKEY_CURRENT_USER_LOCAL_SETTINGS`
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// # use winreg::RegKey;
+    /// # use winreg::enums::*;
+    /// let hklm = RegKey::predef(HKEY_LOCAL_MACHINE);
+    /// ```
+    pub const fn predef(hkey: HKEY) -> RegKey {
+        RegKey { hkey }
+    }
+
+    /// Load a registry hive from a file as an application hive.
+    /// If `lock` is set to `true`, then the hive cannot be loaded again until
+    /// it's unloaded (i.e. all keys from it go out of scope).
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// # use std::error::Error;
+    /// # use winreg::RegKey;
+    /// # use winreg::enums::*;
+    /// # fn main() -> Result<(), Box<dyn Error>> {
+    /// let handle = RegKey::load_app_key("C:\\myhive.dat", false)?;
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub fn load_app_key<N: AsRef<OsStr>>(filename: N, lock: bool) -> io::Result<RegKey> {
+        let options = if lock {
+            winapi_reg::REG_PROCESS_APPKEY
+        } else {
+            0
+        };
+        RegKey::load_app_key_with_flags(filename, enums::KEY_ALL_ACCESS, options)
+    }
+
+    /// Load a registry hive from a file as an application hive with desired
+    /// permissions and options. If `options` is set to `REG_PROCESS_APPKEY`,
+    /// then the hive cannot be loaded again until it's unloaded (i.e. all keys
+    /// from it go out of scope).
+    /// # Examples
+    ///
+    /// ```no_run
+    /// # use std::error::Error;
+    /// # use winreg::RegKey;
+    /// # use winreg::enums::*;
+    /// # fn main() -> Result<(), Box<dyn Error>> {
+    /// let handle = RegKey::load_app_key_with_flags("C:\\myhive.dat", KEY_READ, 0)?;
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub fn load_app_key_with_flags<N: AsRef<OsStr>>(
+        filename: N,
+        perms: winapi_reg::REGSAM,
+        options: DWORD,
+    ) -> io::Result<RegKey> {
+        let c_filename = to_utf16(filename);
+        let mut new_hkey: HKEY = ptr::null_mut();
+        match unsafe {
+            winapi_reg::RegLoadAppKeyW(c_filename.as_ptr(), &mut new_hkey, perms, options, 0)
+                as DWORD
+        } {
+            0 => Ok(RegKey { hkey: new_hkey }),
+            err => werr!(err),
+        }
+    }
+
+    /// Return inner winapi HKEY of a key:
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// # use std::error::Error;
+    /// # use winreg::RegKey;
+    /// # use winreg::enums::*;
+    /// # fn main() -> Result<(), Box<dyn Error>> {
+    /// let hklm = RegKey::predef(HKEY_LOCAL_MACHINE);
+    /// let soft = hklm.open_subkey("SOFTWARE")?;
+    /// let handle = soft.raw_handle();
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub const fn raw_handle(&self) -> HKEY {
+        self.hkey
+    }
+
+    /// Open subkey with `KEY_READ` permissions.
+    /// Will open another handle to itself if `path` is an empty string.
+    /// To open with different permissions use `open_subkey_with_flags`.
+    /// You can also use `create_subkey` to open with `KEY_ALL_ACCESS` permissions.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// # use std::error::Error;
+    /// # use winreg::RegKey;
+    /// # use winreg::enums::*;
+    /// # fn main() -> Result<(), Box<dyn Error>> {
+    /// let soft = RegKey::predef(HKEY_CURRENT_USER)
+    ///     .open_subkey("Software")?;
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub fn open_subkey<P: AsRef<OsStr>>(&self, path: P) -> io::Result<RegKey> {
+        self.open_subkey_with_flags(path, enums::KEY_READ)
+    }
+
+    /// Open subkey with desired permissions.
+    /// Will open another handle to itself if `path` is an empty string.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// # use std::error::Error;
+    /// # use winreg::RegKey;
+    /// # use winreg::enums::*;
+    /// # fn main() -> Result<(), Box<dyn Error>> {
+    /// let hklm = RegKey::predef(HKEY_LOCAL_MACHINE);
+    /// hklm.open_subkey_with_flags("SOFTWARE\\Microsoft", KEY_READ)?;
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub fn open_subkey_with_flags<P: AsRef<OsStr>>(
+        &self,
+        path: P,
+        perms: winapi_reg::REGSAM,
+    ) -> io::Result<RegKey> {
+        let c_path = to_utf16(path);
+        let mut new_hkey: HKEY = ptr::null_mut();
+        match unsafe {
+            winapi_reg::RegOpenKeyExW(self.hkey, c_path.as_ptr(), 0, perms, &mut new_hkey) as DWORD
+        } {
+            0 => Ok(RegKey { hkey: new_hkey }),
+            err => werr!(err),
+        }
+    }
+
+    /// Part of `transactions` feature.
+    #[cfg(feature = "transactions")]
+    pub fn open_subkey_transacted<P: AsRef<OsStr>>(
+        &self,
+        path: P,
+        t: &Transaction,
+    ) -> io::Result<RegKey> {
+        self.open_subkey_transacted_with_flags(path, t, winnt::KEY_READ)
+    }
+
+    /// Part of `transactions` feature.
+    #[cfg(feature = "transactions")]
+    pub fn open_subkey_transacted_with_flags<P: AsRef<OsStr>>(
+        &self,
+        path: P,
+        t: &Transaction,
+        perms: winapi_reg::REGSAM,
+    ) -> io::Result<RegKey> {
+        let c_path = to_utf16(path);
+        let mut new_hkey: HKEY = ptr::null_mut();
+        match unsafe {
+            winapi_reg::RegOpenKeyTransactedW(
+                self.hkey,
+                c_path.as_ptr(),
+                0,
+                perms,
+                &mut new_hkey,
+                t.handle,
+                ptr::null_mut(),
+            ) as DWORD
+        } {
+            0 => Ok(RegKey { hkey: new_hkey }),
+            err => werr!(err),
+        }
+    }
+
+    /// Create subkey (and all missing parent keys)
+    /// and open it with `KEY_ALL_ACCESS` permissions.
+    /// Will just open key if it already exists.
+    /// If succeeds returns a tuple with the created subkey and its disposition,
+    /// which can be `REG_CREATED_NEW_KEY` or `REG_OPENED_EXISTING_KEY`.
+    /// Will open another handle to itself if `path` is an empty string.
+    /// To create with different permissions use `create_subkey_with_flags`.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// # use std::error::Error;
+    /// # use winreg::RegKey;
+    /// use winreg::enums::*;
+    /// # fn main() -> Result<(), Box<dyn Error>> {
+    /// let hkcu = RegKey::predef(HKEY_CURRENT_USER);
+    /// let (settings, disp) = hkcu.create_subkey("Software\\MyProduct\\Settings")?;
+    ///
+    /// match disp {
+    ///     REG_CREATED_NEW_KEY => println!("A new key has been created"),
+    ///     REG_OPENED_EXISTING_KEY => println!("An existing key has been opened")
+    /// }
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub fn create_subkey<P: AsRef<OsStr>>(&self, path: P) -> io::Result<(RegKey, RegDisposition)> {
+        self.create_subkey_with_flags(path, enums::KEY_ALL_ACCESS)
+    }
+
+    pub fn create_subkey_with_flags<P: AsRef<OsStr>>(
+        &self,
+        path: P,
+        perms: winapi_reg::REGSAM,
+    ) -> io::Result<(RegKey, RegDisposition)> {
+        let c_path = to_utf16(path);
+        let mut new_hkey: HKEY = ptr::null_mut();
+        let mut disp_buf: DWORD = 0;
+        match unsafe {
+            winapi_reg::RegCreateKeyExW(
+                self.hkey,
+                c_path.as_ptr(),
+                0,
+                ptr::null_mut(),
+                winnt::REG_OPTION_NON_VOLATILE,
+                perms,
+                ptr::null_mut(),
+                &mut new_hkey,
+                &mut disp_buf,
+            )
+        } {
+            0 => {
+                let disp: RegDisposition = unsafe { transmute(disp_buf as u8) };
+                Ok((RegKey { hkey: new_hkey }, disp))
+            }
+            err => werr!(err),
+        }
+    }
+
+    /// Part of `transactions` feature.
+    #[cfg(feature = "transactions")]
+    pub fn create_subkey_transacted<P: AsRef<OsStr>>(
+        &self,
+        path: P,
+        t: &Transaction,
+    ) -> io::Result<(RegKey, RegDisposition)> {
+        self.create_subkey_transacted_with_flags(path, t, winnt::KEY_ALL_ACCESS)
+    }
+
+    /// Part of `transactions` feature.
+    #[cfg(feature = "transactions")]
+    pub fn create_subkey_transacted_with_flags<P: AsRef<OsStr>>(
+        &self,
+        path: P,
+        t: &Transaction,
+        perms: winapi_reg::REGSAM,
+    ) -> io::Result<(RegKey, RegDisposition)> {
+        let c_path = to_utf16(path);
+        let mut new_hkey: HKEY = ptr::null_mut();
+        let mut disp_buf: DWORD = 0;
+        match unsafe {
+            winapi_reg::RegCreateKeyTransactedW(
+                self.hkey,
+                c_path.as_ptr(),
+                0,
+                ptr::null_mut(),
+                winnt::REG_OPTION_NON_VOLATILE,
+                perms,
+                ptr::null_mut(),
+                &mut new_hkey,
+                &mut disp_buf,
+                t.handle,
+                ptr::null_mut(),
+            ) as DWORD
+        } {
+            0 => {
+                let disp: RegDisposition = unsafe { transmute(disp_buf as u8) };
+                Ok((RegKey { hkey: new_hkey }, disp))
+            }
+            err => werr!(err),
+        }
+    }
+
+    /// Copy all the values and subkeys from `path` to `dest` key.
+    /// WIll copy the content of `self` if `path` is an empty string.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// # use std::error::Error;
+    /// # use winreg::RegKey;
+    /// # use winreg::enums::*;
+    /// # fn main() -> Result<(), Box<dyn Error>> {
+    /// let hkcu = RegKey::predef(HKEY_CURRENT_USER);
+    /// let src = hkcu.open_subkey_with_flags("Software\\MyProduct", KEY_READ)?;
+    /// let (dst, dst_disp) = hkcu.create_subkey("Software\\MyProduct\\Section2")?;
+    /// src.copy_tree("Section1", &dst)?;
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub fn copy_tree<P: AsRef<OsStr>>(&self, path: P, dest: &RegKey) -> io::Result<()> {
+        let c_path = to_utf16(path);
+        match unsafe { winapi_reg::RegCopyTreeW(self.hkey, c_path.as_ptr(), dest.hkey) } {
+            0 => Ok(()),
+            err => werr!(err),
+        }
+    }
+
+    pub fn query_info(&self) -> io::Result<RegKeyMetadata> {
+        let mut info: RegKeyMetadata = Default::default();
+        match unsafe {
+            winapi_reg::RegQueryInfoKeyW(
+                self.hkey,
+                ptr::null_mut(), // Class: winapi::LPWSTR,
+                ptr::null_mut(), // ClassLen: DWORD,
+                ptr::null_mut(), // Reserved
+                &mut info.sub_keys,
+                &mut info.max_sub_key_len,
+                &mut info.max_class_len,
+                &mut info.values,
+                &mut info.max_value_name_len,
+                &mut info.max_value_len,
+                ptr::null_mut(), // lpcbSecurityDescriptor: winapi::LPDWORD,
+                &mut info.last_write_time,
+            ) as DWORD
+        } {
+            0 => Ok(info),
+            err => werr!(err),
+        }
+    }
+
+    /// Return an iterator over subkeys names.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// # use winreg::RegKey;
+    /// # use winreg::enums::*;
+    /// println!("File extensions, registered in this system:");
+    /// for i in RegKey::predef(HKEY_CLASSES_ROOT)
+    ///     .enum_keys().map(|x| x.unwrap())
+    ///     .filter(|x| x.starts_with("."))
+    /// {
+    ///     println!("{}", i);
+    /// }
+    /// ```
+    pub const fn enum_keys(&self) -> EnumKeys {
+        EnumKeys {
+            key: self,
+            index: 0,
+        }
+    }
+
+    /// Return an iterator over values.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// # use std::error::Error;
+    /// # use winreg::RegKey;
+    /// # use winreg::enums::*;
+    /// # fn main() -> Result<(), Box<dyn Error>> {
+    /// let system = RegKey::predef(HKEY_LOCAL_MACHINE)
+    ///     .open_subkey_with_flags("HARDWARE\\DESCRIPTION\\System", KEY_READ)?;
+    /// for (name, value) in system.enum_values().map(|x| x.unwrap()) {
+    ///     println!("{} = {:?}", name, value);
+    /// }
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub const fn enum_values(&self) -> EnumValues {
+        EnumValues {
+            key: self,
+            index: 0,
+        }
+    }
+
+    /// Delete key. Key names are not case sensitive.
+    /// Cannot delete if it has subkeys.
+    /// Use `delete_subkey_all` for that.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// # use std::error::Error;
+    /// # use winreg::RegKey;
+    /// # use winreg::enums::*;
+    /// # fn main() -> Result<(), Box<dyn Error>> {
+    /// RegKey::predef(HKEY_CURRENT_USER)
+    ///     .delete_subkey(r"Software\MyProduct\History")?;
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub fn delete_subkey<P: AsRef<OsStr>>(&self, path: P) -> io::Result<()> {
+        self.delete_subkey_with_flags(path, 0)
+    }
+
+    /// Delete key from the desired platform-specific view of the registry.
+    /// Key names are not case sensitive.
+    ///
+    /// # Examples
+    /// ```no_run
+    /// # use std::error::Error;
+    /// # use winreg::RegKey;
+    /// # use winreg::enums::*;
+    /// # fn main() -> Result<(), Box<dyn Error>> {
+    /// // delete the key from the 32-bit registry view
+    /// RegKey::predef(HKEY_LOCAL_MACHINE)
+    ///     .delete_subkey_with_flags(r"Software\MyProduct\History", KEY_WOW64_32KEY)?;
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub fn delete_subkey_with_flags<P: AsRef<OsStr>>(
+        &self,
+        path: P,
+        perms: winapi_reg::REGSAM,
+    ) -> io::Result<()> {
+        let c_path = to_utf16(path);
+        match unsafe {
+            winapi_reg::RegDeleteKeyExW(
+                self.hkey,
+                c_path.as_ptr(), // This parameter cannot be NULL.
+                perms,
+                0,
+            )
+        } {
+            0 => Ok(()),
+            err => werr!(err),
+        }
+    }
+
+    /// Part of `transactions` feature.
+    #[cfg(feature = "transactions")]
+    pub fn delete_subkey_transacted<P: AsRef<OsStr>>(
+        &self,
+        path: P,
+        t: &Transaction,
+    ) -> io::Result<()> {
+        self.delete_subkey_transacted_with_flags(path, t, 0)
+    }
+
+    /// Part of `transactions` feature.
+    #[cfg(feature = "transactions")]
+    pub fn delete_subkey_transacted_with_flags<P: AsRef<OsStr>>(
+        &self,
+        path: P,
+        t: &Transaction,
+        perms: winapi_reg::REGSAM,
+    ) -> io::Result<()> {
+        let c_path = to_utf16(path);
+        match unsafe {
+            winapi_reg::RegDeleteKeyTransactedW(
+                self.hkey,
+                c_path.as_ptr(), // This parameter cannot be NULL.
+                perms,
+                0,
+                t.handle,
+                ptr::null_mut(),
+            )
+        } {
+            0 => Ok(()),
+            err => werr!(err),
+        }
+    }
+
+    /// Recursively delete subkey with all its subkeys and values.
+    /// If `path` is an empty string, the subkeys and values of this key are deleted.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// # use std::error::Error;
+    /// # use winreg::RegKey;
+    /// # use winreg::enums::*;
+    /// # fn main() -> Result<(), Box<dyn Error>> {
+    /// RegKey::predef(HKEY_CURRENT_USER)
+    ///     .delete_subkey_all("Software\\MyProduct")?;
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub fn delete_subkey_all<P: AsRef<OsStr>>(&self, path: P) -> io::Result<()> {
+        let c_path;
+        let path_ptr = if path.as_ref().is_empty() {
+            ptr::null()
+        } else {
+            c_path = to_utf16(path);
+            c_path.as_ptr()
+        };
+        match unsafe {
+            winapi_reg::RegDeleteTreeW(
+                self.hkey,
+                path_ptr, //If this parameter is NULL, the subkeys and values of this key are deleted.
+            ) as DWORD
+        } {
+            0 => Ok(()),
+            err => werr!(err),
+        }
+    }
+
+    /// Get a value from registry and seamlessly convert it to the specified rust type
+    /// with `FromRegValue` implemented (currently `String`, `u32` and `u64`).
+    /// Will get the `Default` value if `name` is an empty string.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// # use std::error::Error;
+    /// # use winreg::RegKey;
+    /// # use winreg::enums::*;
+    /// # fn main() -> Result<(), Box<dyn Error>> {
+    /// let hkcu = RegKey::predef(HKEY_CURRENT_USER);
+    /// let settings = hkcu.open_subkey("Software\\MyProduct\\Settings")?;
+    /// let server: String = settings.get_value("server")?;
+    /// let port: u32 = settings.get_value("port")?;
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub fn get_value<T: FromRegValue, N: AsRef<OsStr>>(&self, name: N) -> io::Result<T> {
+        match self.get_raw_value(name) {
+            Ok(ref val) => FromRegValue::from_reg_value(val),
+            Err(err) => Err(err),
+        }
+    }
+
+    /// Get raw bytes from registry value.
+    /// Will get the `Default` value if `name` is an empty string.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// # use std::error::Error;
+    /// # use winreg::RegKey;
+    /// # use winreg::enums::*;
+    /// # fn main() -> Result<(), Box<dyn Error>> {
+    /// let hkcu = RegKey::predef(HKEY_CURRENT_USER);
+    /// let settings = hkcu.open_subkey("Software\\MyProduct\\Settings")?;
+    /// let data = settings.get_raw_value("data")?;
+    /// println!("Bytes: {:?}", data.bytes);
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub fn get_raw_value<N: AsRef<OsStr>>(&self, name: N) -> io::Result<RegValue> {
+        let c_name = to_utf16(name);
+        let mut buf_len: DWORD = 2048;
+        let mut buf_type: DWORD = 0;
+        let mut buf: Vec<u8> = Vec::with_capacity(buf_len as usize);
+        loop {
+            match unsafe {
+                winapi_reg::RegQueryValueExW(
+                    self.hkey,
+                    c_name.as_ptr() as *const u16,
+                    ptr::null_mut(),
+                    &mut buf_type,
+                    buf.as_mut_ptr() as LPBYTE,
+                    &mut buf_len,
+                ) as DWORD
+            } {
+                0 => {
+                    unsafe {
+                        buf.set_len(buf_len as usize);
+                    }
+                    // minimal check before transmute to RegType
+                    if buf_type > winnt::REG_QWORD {
+                        return werr!(winerror::ERROR_BAD_FILE_TYPE);
+                    }
+                    let t: RegType = unsafe { transmute(buf_type as u8) };
+                    return Ok(RegValue {
+                        bytes: buf,
+                        vtype: t,
+                    });
+                }
+                winerror::ERROR_MORE_DATA => {
+                    buf.reserve(buf_len as usize);
+                }
+                err => return werr!(err),
+            }
+        }
+    }
+
+    /// Seamlessly convert a value from a rust type and write it to the registry value
+    /// with `ToRegValue` trait implemented (currently `String`, `&str`, `u32` and `u64`).
+    /// Will set the `Default` value if `name` is an empty string.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// # use std::error::Error;
+    /// # use winreg::RegKey;
+    /// # use winreg::enums::*;
+    /// # fn main() -> Result<(), Box<dyn Error>> {
+    /// let hkcu = RegKey::predef(HKEY_CURRENT_USER);
+    /// let (settings, disp) = hkcu.create_subkey("Software\\MyProduct\\Settings")?;
+    /// settings.set_value("server", &"www.example.com")?;
+    /// settings.set_value("port", &8080u32)?;
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub fn set_value<T: ToRegValue, N: AsRef<OsStr>>(&self, name: N, value: &T) -> io::Result<()> {
+        self.set_raw_value(name, &value.to_reg_value())
+    }
+
+    /// Write raw bytes from `RegValue` struct to a registry value.
+    /// Will set the `Default` value if `name` is an empty string.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// # use std::error::Error;
+    /// use winreg::{RegKey, RegValue};
+    /// use winreg::enums::*;
+    /// # fn main() -> Result<(), Box<dyn Error>> {
+    /// let hkcu = RegKey::predef(HKEY_CURRENT_USER);
+    /// let settings = hkcu.open_subkey("Software\\MyProduct\\Settings")?;
+    /// let bytes: Vec<u8> = vec![1, 2, 3, 5, 8, 13, 21, 34, 55, 89];
+    /// let data = RegValue{ vtype: REG_BINARY, bytes: bytes};
+    /// settings.set_raw_value("data", &data)?;
+    /// println!("Bytes: {:?}", data.bytes);
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub fn set_raw_value<N: AsRef<OsStr>>(&self, name: N, value: &RegValue) -> io::Result<()> {
+        let c_name = to_utf16(name);
+        let t = value.vtype.clone() as DWORD;
+        match unsafe {
+            winapi_reg::RegSetValueExW(
+                self.hkey,
+                c_name.as_ptr(),
+                0,
+                t,
+                value.bytes.as_ptr() as *const BYTE,
+                value.bytes.len() as u32,
+            ) as DWORD
+        } {
+            0 => Ok(()),
+            err => werr!(err),
+        }
+    }
+
+    /// Delete specified value from registry.
+    /// Will delete the `Default` value if `name` is an empty string.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// # use std::error::Error;
+    /// # use winreg::RegKey;
+    /// # use winreg::enums::*;
+    /// # fn main() -> Result<(), Box<dyn Error>> {
+    /// let hkcu = RegKey::predef(HKEY_CURRENT_USER);
+    /// let settings = hkcu.open_subkey("Software\\MyProduct\\Settings")?;
+    /// settings.delete_value("data")?;
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub fn delete_value<N: AsRef<OsStr>>(&self, name: N) -> io::Result<()> {
+        let c_name = to_utf16(name);
+        match unsafe { winapi_reg::RegDeleteValueW(self.hkey, c_name.as_ptr()) as DWORD } {
+            0 => Ok(()),
+            err => werr!(err),
+        }
+    }
+
+    /// Save `Encodable` type to a registry key.
+    /// Part of `serialization-serde` feature.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// # use std::error::Error;
+    /// #[macro_use]
+    /// extern crate serde_derive;
+    /// extern crate winreg;
+    /// use winreg::RegKey;
+    /// use winreg::enums::*;
+    ///
+    /// #[derive(Serialize)]
+    /// struct Rectangle{
+    ///     x: u32,
+    ///     y: u32,
+    ///     w: u32,
+    ///     h: u32,
+    /// }
+    ///
+    /// #[derive(Serialize)]
+    /// struct Settings{
+    ///     current_dir: String,
+    ///     window_pos: Rectangle,
+    ///     show_in_tray: bool,
+    /// }
+    ///
+    /// # fn main() -> Result<(), Box<dyn Error>> {
+    /// let s: Settings = Settings{
+    ///     current_dir: "C:\\".to_owned(),
+    ///     window_pos: Rectangle{ x:200, y: 100, w: 800, h: 500 },
+    ///     show_in_tray: false,
+    /// };
+    /// let s_key = RegKey::predef(HKEY_CURRENT_USER)
+    ///     .open_subkey("Software\\MyProduct\\Settings")?;
+    /// s_key.encode(&s)?;
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[cfg(feature = "serialization-serde")]
+    pub fn encode<T: serde::Serialize>(&self, value: &T) -> encoder::EncodeResult<()> {
+        let mut encoder = encoder::Encoder::from_key(self)?;
+        value.serialize(&mut encoder)?;
+        encoder.commit()
+    }
+
+    /// Load `Decodable` type from a registry key.
+    /// Part of `serialization-serde` feature.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// # use std::error::Error;
+    /// #[macro_use]
+    /// extern crate serde_derive;
+    /// extern crate winreg;
+    /// use winreg::RegKey;
+    /// use winreg::enums::*;
+    ///
+    /// #[derive(Deserialize)]
+    /// struct Rectangle{
+    ///     x: u32,
+    ///     y: u32,
+    ///     w: u32,
+    ///     h: u32,
+    /// }
+    ///
+    /// #[derive(Deserialize)]
+    /// struct Settings{
+    ///     current_dir: String,
+    ///     window_pos: Rectangle,
+    ///     show_in_tray: bool,
+    /// }
+    ///
+    /// # fn main() -> Result<(), Box<dyn Error>> {
+    /// let s_key = RegKey::predef(HKEY_CURRENT_USER)
+    ///     .open_subkey("Software\\MyProduct\\Settings")?;
+    /// let s: Settings = s_key.decode()?;
+    /// # Ok(())
+    /// # }
+    /// ```
+    #[cfg(feature = "serialization-serde")]
+    pub fn decode<'de, T: serde::Deserialize<'de>>(&self) -> decoder::DecodeResult<T> {
+        let mut decoder = decoder::Decoder::from_key(self)?;
+        T::deserialize(&mut decoder)
+    }
+
+    fn close_(&mut self) -> io::Result<()> {
+        // don't try to close predefined keys
+        if self.hkey >= enums::HKEY_CLASSES_ROOT {
+            return Ok(());
+        };
+        match unsafe { winapi_reg::RegCloseKey(self.hkey) as DWORD } {
+            0 => Ok(()),
+            err => werr!(err),
+        }
+    }
+
+    fn enum_key(&self, index: DWORD) -> Option<io::Result<String>> {
+        let mut name_len = 2048;
+        #[allow(clippy::unnecessary_cast)]
+        let mut name = [0 as WCHAR; 2048];
+        match unsafe {
+            winapi_reg::RegEnumKeyExW(
+                self.hkey,
+                index,
+                name.as_mut_ptr(),
+                &mut name_len,
+                ptr::null_mut(), // reserved
+                ptr::null_mut(), // lpClass: LPWSTR,
+                ptr::null_mut(), // lpcClass: LPDWORD,
+                ptr::null_mut(), // lpftLastWriteTime: PFILETIME,
+            ) as DWORD
+        } {
+            0 => match String::from_utf16(&name[..name_len as usize]) {
+                Ok(s) => Some(Ok(s)),
+                Err(_) => Some(werr!(winerror::ERROR_INVALID_BLOCK)),
+            },
+            winerror::ERROR_NO_MORE_ITEMS => None,
+            err => Some(werr!(err)),
+        }
+    }
+
+    fn enum_value(&self, index: DWORD) -> Option<io::Result<(String, RegValue)>> {
+        let mut name_len = 2048;
+        #[allow(clippy::unnecessary_cast)]
+        let mut name = [0 as WCHAR; 2048];
+
+        let mut buf_len: DWORD = 2048;
+        let mut buf_type: DWORD = 0;
+        let mut buf: Vec<u8> = Vec::with_capacity(buf_len as usize);
+        loop {
+            match unsafe {
+                winapi_reg::RegEnumValueW(
+                    self.hkey,
+                    index,
+                    name.as_mut_ptr(),
+                    &mut name_len,
+                    ptr::null_mut(), // reserved
+                    &mut buf_type,
+                    buf.as_mut_ptr() as LPBYTE,
+                    &mut buf_len,
+                ) as DWORD
+            } {
+                0 => {
+                    let name = match String::from_utf16(&name[..name_len as usize]) {
+                        Ok(s) => s,
+                        Err(_) => return Some(werr!(winerror::ERROR_INVALID_DATA)),
+                    };
+                    unsafe {
+                        buf.set_len(buf_len as usize);
+                    }
+                    // minimal check before transmute to RegType
+                    if buf_type > winnt::REG_QWORD {
+                        return Some(werr!(winerror::ERROR_BAD_FILE_TYPE));
+                    }
+                    let t: RegType = unsafe { transmute(buf_type as u8) };
+                    let value = RegValue {
+                        bytes: buf,
+                        vtype: t,
+                    };
+                    return Some(Ok((name, value)));
+                }
+                winerror::ERROR_MORE_DATA => {
+                    name_len += 1; //for NULL char
+                    buf.reserve(buf_len as usize);
+                }
+                winerror::ERROR_NO_MORE_ITEMS => return None,
+                err => return Some(werr!(err)),
+            }
+        }
+    }
+}
+
+impl Drop for RegKey {
+    fn drop(&mut self) {
+        self.close_().unwrap_or(());
+    }
+}
+
+/// Iterator over subkeys names
+pub struct EnumKeys<'key> {
+    key: &'key RegKey,
+    index: DWORD,
+}
+
+impl<'key> Iterator for EnumKeys<'key> {
+    type Item = io::Result<String>;
+
+    fn next(&mut self) -> Option<io::Result<String>> {
+        match self.key.enum_key(self.index) {
+            v @ Some(_) => {
+                self.index += 1;
+                v
+            }
+            e @ None => e,
+        }
+    }
+
+    fn nth(&mut self, n: usize) -> Option<Self::Item> {
+        self.index += n as DWORD;
+        self.next()
+    }
+}
+
+/// Iterator over values
+pub struct EnumValues<'key> {
+    key: &'key RegKey,
+    index: DWORD,
+}
+
+impl<'key> Iterator for EnumValues<'key> {
+    type Item = io::Result<(String, RegValue)>;
+
+    fn next(&mut self) -> Option<io::Result<(String, RegValue)>> {
+        match self.key.enum_value(self.index) {
+            v @ Some(_) => {
+                self.index += 1;
+                v
+            }
+            e @ None => e,
+        }
+    }
+
+    fn nth(&mut self, n: usize) -> Option<Self::Item> {
+        self.index += n as DWORD;
+        self.next()
+    }
+}
+
+fn to_utf16<P: AsRef<OsStr>>(s: P) -> Vec<u16> {
+    s.as_ref()
+        .encode_wide()
+        .chain(Some(0).into_iter())
+        .collect()
+}
+
+fn v16_to_v8(v: &[u16]) -> Vec<u8> {
+    unsafe { slice::from_raw_parts(v.as_ptr() as *const u8, v.len() * 2).to_vec() }
+}
diff --git a/third_party/rust/winreg/src/transaction.rs b/third_party/rust/winreg/src/transaction.rs
new file mode 100644
index 0000000000..e63e3ea17c
--- /dev/null
+++ b/third_party/rust/winreg/src/transaction.rs
@@ -0,0 +1,105 @@
+// Copyright 2015, Igor Shaula
+// Licensed under the MIT License <LICENSE or
+// http://opensource.org/licenses/MIT>. This file
+// may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Structure for a registry transaction.
+//! Part of `transactions` feature.
+//!
+//!```no_run
+//!extern crate winreg;
+//!use std::io;
+//!use winreg::RegKey;
+//!use winreg::enums::*;
+//!use winreg::transaction::Transaction;
+//!
+//!fn main() {
+//!    let t = Transaction::new().unwrap();
+//!    let hkcu = RegKey::predef(HKEY_CURRENT_USER);
+//!    let (key, _disp) = hkcu.create_subkey_transacted("Software\\RustTransaction", &t).unwrap();
+//!    key.set_value("TestQWORD", &1234567891011121314u64).unwrap();
+//!    key.set_value("TestDWORD", &1234567890u32).unwrap();
+//!
+//!    println!("Commit transaction? [y/N]:");
+//!    let mut input = String::new();
+//!    io::stdin().read_line(&mut input).unwrap();
+//!    input = input.trim_right().to_owned();
+//!    if input == "y" || input == "Y" {
+//!        t.commit().unwrap();
+//!        println!("Transaction committed.");
+//!    }
+//!    else {
+//!        // this is optional, if transaction wasn't committed,
+//!        // it will be rolled back on disposal
+//!        t.rollback().unwrap();
+//!
+//!        println!("Transaction wasn't committed, it will be rolled back.");
+//!    }
+//!}
+//!```
+#![cfg(feature = "transactions")]
+use std::io;
+use std::ptr;
+use winapi::um::handleapi;
+use winapi::um::ktmw32;
+use winapi::um::winnt;
+
+#[derive(Debug)]
+pub struct Transaction {
+    pub handle: winnt::HANDLE,
+}
+
+impl Transaction {
+    //TODO: add arguments
+    pub fn new() -> io::Result<Transaction> {
+        unsafe {
+            let handle = ktmw32::CreateTransaction(
+                ptr::null_mut(),
+                ptr::null_mut(),
+                0,
+                0,
+                0,
+                0,
+                ptr::null_mut(),
+            );
+            if handle == handleapi::INVALID_HANDLE_VALUE {
+                return Err(io::Error::last_os_error());
+            };
+            Ok(Transaction { handle })
+        }
+    }
+
+    pub fn commit(&self) -> io::Result<()> {
+        unsafe {
+            match ktmw32::CommitTransaction(self.handle) {
+                0 => Err(io::Error::last_os_error()),
+                _ => Ok(()),
+            }
+        }
+    }
+
+    pub fn rollback(&self) -> io::Result<()> {
+        unsafe {
+            match ktmw32::RollbackTransaction(self.handle) {
+                0 => Err(io::Error::last_os_error()),
+                _ => Ok(()),
+            }
+        }
+    }
+
+    fn close_(&mut self) -> io::Result<()> {
+        unsafe {
+            match handleapi::CloseHandle(self.handle) {
+                0 => Err(io::Error::last_os_error()),
+                _ => Ok(()),
+            }
+        }
+    }
+}
+
+impl Drop for Transaction {
+    fn drop(&mut self) {
+        self.close_().unwrap_or(());
+    }
+}
diff --git a/third_party/rust/winreg/src/types.rs b/third_party/rust/winreg/src/types.rs
new file mode 100644
index 0000000000..37439354eb
--- /dev/null
+++ b/third_party/rust/winreg/src/types.rs
@@ -0,0 +1,199 @@
+// Copyright 2015, Igor Shaula
+// Licensed under the MIT License <LICENSE or
+// http://opensource.org/licenses/MIT>. This file
+// may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Traits for loading/saving Registry values
+use super::enums::*;
+use super::winapi::shared::winerror;
+use super::RegValue;
+use super::{to_utf16, v16_to_v8};
+use std::ffi::{OsStr, OsString};
+use std::io;
+use std::os::windows::ffi::OsStringExt;
+use std::slice;
+
+/// A trait for types that can be loaded from registry values.
+///
+/// **NOTE:** Uses `from_utf16_lossy` when converting to `String`.
+///
+/// **NOTE:** When converting to `String` or `OsString`, trailing `NULL` characters are trimmed
+/// and line separating `NULL` characters in `REG_MULTI_SZ` are replaced by `\n`
+/// effectively representing the value as a multiline string.
+/// When converting to `Vec<String>` or `Vec<OsString>` `NULL` is used as a strings separator.
+pub trait FromRegValue: Sized {
+    fn from_reg_value(val: &RegValue) -> io::Result<Self>;
+}
+
+impl FromRegValue for String {
+    fn from_reg_value(val: &RegValue) -> io::Result<String> {
+        match val.vtype {
+            REG_SZ | REG_EXPAND_SZ | REG_MULTI_SZ => {
+                let words = unsafe {
+                    #[allow(clippy::cast_ptr_alignment)]
+                    slice::from_raw_parts(val.bytes.as_ptr() as *const u16, val.bytes.len() / 2)
+                };
+                let mut s = String::from_utf16_lossy(words);
+                while s.ends_with('\u{0}') {
+                    s.pop();
+                }
+                if val.vtype == REG_MULTI_SZ {
+                    return Ok(s.replace("\u{0}", "\n"));
+                }
+                Ok(s)
+            }
+            _ => werr!(winerror::ERROR_BAD_FILE_TYPE),
+        }
+    }
+}
+
+impl FromRegValue for Vec<String> {
+    fn from_reg_value(val: &RegValue) -> io::Result<Vec<String>> {
+        match val.vtype {
+            REG_MULTI_SZ => {
+                let words = unsafe {
+                    slice::from_raw_parts(val.bytes.as_ptr() as *const u16, val.bytes.len() / 2)
+                };
+                let mut s = String::from_utf16_lossy(words);
+                while s.ends_with('\u{0}') {
+                    s.pop();
+                }
+                let v: Vec<String> = s.split('\u{0}').map(|x| x.to_owned()).collect();
+                Ok(v)
+            }
+            _ => werr!(winerror::ERROR_BAD_FILE_TYPE),
+        }
+    }
+}
+
+impl FromRegValue for OsString {
+    fn from_reg_value(val: &RegValue) -> io::Result<OsString> {
+        match val.vtype {
+            REG_SZ | REG_EXPAND_SZ | REG_MULTI_SZ => {
+                let mut words = unsafe {
+                    #[allow(clippy::cast_ptr_alignment)]
+                    slice::from_raw_parts(val.bytes.as_ptr() as *const u16, val.bytes.len() / 2)
+                };
+                while let Some(0) = words.last() {
+                    words = &words[0..words.len() - 1];
+                }
+                let s = OsString::from_wide(words);
+                Ok(s)
+            }
+            _ => werr!(winerror::ERROR_BAD_FILE_TYPE),
+        }
+    }
+}
+
+impl FromRegValue for Vec<OsString> {
+    fn from_reg_value(val: &RegValue) -> io::Result<Vec<OsString>> {
+        match val.vtype {
+            REG_MULTI_SZ => {
+                let mut words = unsafe {
+                    slice::from_raw_parts(val.bytes.as_ptr() as *const u16, val.bytes.len() / 2)
+                };
+                while let Some(0) = words.last() {
+                    words = &words[0..words.len() - 1];
+                }
+                let v: Vec<OsString> = words
+                    .split(|ch| *ch == 0u16)
+                    .map(|x| OsString::from_wide(x))
+                    .collect();
+                Ok(v)
+            }
+            _ => werr!(winerror::ERROR_BAD_FILE_TYPE),
+        }
+    }
+}
+
+impl FromRegValue for u32 {
+    fn from_reg_value(val: &RegValue) -> io::Result<u32> {
+        match val.vtype {
+            #[allow(clippy::cast_ptr_alignment)]
+            REG_DWORD => Ok(unsafe { *(val.bytes.as_ptr() as *const u32) }),
+            _ => werr!(winerror::ERROR_BAD_FILE_TYPE),
+        }
+    }
+}
+
+impl FromRegValue for u64 {
+    fn from_reg_value(val: &RegValue) -> io::Result<u64> {
+        match val.vtype {
+            #[allow(clippy::cast_ptr_alignment)]
+            REG_QWORD => Ok(unsafe { *(val.bytes.as_ptr() as *const u64) }),
+            _ => werr!(winerror::ERROR_BAD_FILE_TYPE),
+        }
+    }
+}
+
+/// A trait for types that can be written into registry values.
+///
+/// **NOTE:** Adds trailing `NULL` character to `str`, `String`, `OsStr` and `OsString` values
+pub trait ToRegValue {
+    fn to_reg_value(&self) -> RegValue;
+}
+
+macro_rules! to_reg_value_sz {
+    ($t:ty$(, $l:lifetime)*) => {
+        impl<$($l,)*> ToRegValue for $t {
+            fn to_reg_value(&self) -> RegValue {
+                RegValue {
+                    bytes: v16_to_v8(&to_utf16(self)),
+                    vtype: REG_SZ,
+                }
+            }
+        }
+    }
+}
+
+to_reg_value_sz!(String);
+to_reg_value_sz!(&'a str, 'a);
+to_reg_value_sz!(OsString);
+to_reg_value_sz!(&'a OsStr, 'a);
+
+macro_rules! to_reg_value_multi_sz {
+    ($t:ty$(, $l:lifetime)*) => {
+        impl<$($l,)*> ToRegValue for Vec<$t> {
+            fn to_reg_value(&self) -> RegValue {
+                let mut os_strings = self
+                    .into_iter()
+                    .map(to_utf16)
+                    .collect::<Vec<_>>()
+                    .concat();
+                os_strings.push(0);
+                RegValue {
+                    bytes: v16_to_v8(&os_strings),
+                    vtype: REG_MULTI_SZ,
+                }
+            }
+        }
+    }
+}
+
+to_reg_value_multi_sz!(String);
+to_reg_value_multi_sz!(&'a str, 'a);
+to_reg_value_multi_sz!(OsString);
+to_reg_value_multi_sz!(&'a OsStr, 'a);
+
+impl ToRegValue for u32 {
+    fn to_reg_value(&self) -> RegValue {
+        let bytes: Vec<u8> =
+            unsafe { slice::from_raw_parts((self as *const u32) as *const u8, 4).to_vec() };
+        RegValue {
+            bytes,
+            vtype: REG_DWORD,
+        }
+    }
+}
+
+impl ToRegValue for u64 {
+    fn to_reg_value(&self) -> RegValue {
+        let bytes: Vec<u8> =
+            unsafe { slice::from_raw_parts((self as *const u64) as *const u8, 8).to_vec() };
+        RegValue {
+            bytes,
+            vtype: REG_QWORD,
+        }
+    }
+}