use std::{error, fmt};
use serde::ser;
use std::vec::Vec;
use self::seq::SerializeSeq;
use self::struct_::SerializeStruct;
mod seq;
mod struct_;
pub type Result<T> = ::core::result::Result<T, Error>;
#[derive(Debug)]
pub enum Error {
BufferFull,
Custom(String),
#[doc(hidden)]
__Extensible,
}
impl From<()> for Error {
fn from(_: ()) -> Error {
Error::BufferFull
}
}
impl From<u8> for Error {
fn from(_: u8) -> Error {
Error::BufferFull
}
}
impl error::Error for Error {
fn source(&self) -> Option<&(dyn error::Error + 'static)> {
None
}
fn description(&self) -> &str {
"(use display)"
}
}
impl fmt::Display for Error {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
Error::BufferFull => write!(f, "Buffer is full"),
Error::Custom(msg) => write!(f, "{}", &msg),
_ => write!(f, "Unknown serialization error"),
}
}
}
pub struct Serializer {
buf: Vec<u8>,
}
static INITIAL_CAPACITY: usize = 1024;
impl Serializer {
fn new() -> Self {
Serializer {
buf: Vec::with_capacity(INITIAL_CAPACITY),
}
}
}
macro_rules! serialize_unsigned {
($self:ident, $N:expr, $v:expr) => {{
let mut buf = [0u8; $N];
let mut v = $v;
let mut i = $N - 1;
loop {
buf[i] = (v % 10) as u8 + b'0';
v /= 10;
if v == 0 {
break;
} else {
i -= 1;
}
}
$self.buf.extend_from_slice(&buf[i..]);
Ok(())
}};
}
macro_rules! serialize_signed {
($self:ident, $N:expr, $v:expr, $ixx:ident, $uxx:ident) => {{
let v = $v;
let (signed, mut v) = if v == $ixx::min_value() {
(true, $ixx::max_value() as $uxx + 1)
} else if v < 0 {
(true, -v as $uxx)
} else {
(false, v as $uxx)
};
let mut buf = [0u8; $N];
let mut i = $N - 1;
loop {
buf[i] = (v % 10) as u8 + b'0';
v /= 10;
i -= 1;
if v == 0 {
break;
}
}
if signed {
buf[i] = b'-';
} else {
i += 1;
}
$self.buf.extend_from_slice(&buf[i..]);
Ok(())
}};
}
fn hex_4bit(c: u8) -> u8 {
if c <= 9 {
0x30 + c
} else {
0x41 + (c - 10)
}
}
fn hex(c: u8) -> (u8, u8) {
(hex_4bit(c >> 4), hex_4bit(c & 0x0F))
}
impl<'a> ser::Serializer for &'a mut Serializer {
type Ok = ();
type Error = Error;
type SerializeSeq = SerializeSeq<'a>;
type SerializeTuple = SerializeSeq<'a>;
type SerializeTupleStruct = Unreachable;
type SerializeTupleVariant = Unreachable;
type SerializeMap = Unreachable;
type SerializeStruct = SerializeStruct<'a>;
type SerializeStructVariant = SerializeStruct<'a>;
fn serialize_bool(self, v: bool) -> Result<Self::Ok> {
if v {
self.buf.extend_from_slice(b"true");
} else {
self.buf.extend_from_slice(b"false");
}
Ok(())
}
fn serialize_i8(self, v: i8) -> Result<Self::Ok> {
serialize_signed!(self, 4, v, i8, u8)
}
fn serialize_i16(self, v: i16) -> Result<Self::Ok> {
serialize_signed!(self, 6, v, i16, u16)
}
fn serialize_i32(self, v: i32) -> Result<Self::Ok> {
serialize_signed!(self, 11, v, i32, u32)
}
fn serialize_i64(self, v: i64) -> Result<Self::Ok> {
serialize_signed!(self, 20, v, i64, u64)
}
fn serialize_u8(self, v: u8) -> Result<Self::Ok> {
serialize_unsigned!(self, 3, v)
}
fn serialize_u16(self, v: u16) -> Result<Self::Ok> {
serialize_unsigned!(self, 5, v)
}
fn serialize_u32(self, v: u32) -> Result<Self::Ok> {
serialize_unsigned!(self, 10, v)
}
fn serialize_u64(self, v: u64) -> Result<Self::Ok> {
serialize_unsigned!(self, 20, v)
}
fn serialize_f32(self, _v: f32) -> Result<Self::Ok> {
unreachable!()
}
fn serialize_f64(self, _v: f64) -> Result<Self::Ok> {
unreachable!()
}
fn serialize_char(self, _v: char) -> Result<Self::Ok> {
unreachable!()
}
fn serialize_str(self, v: &str) -> Result<Self::Ok> {
self.buf.push(b'"');
let mut encoding_tmp = [0u8; 4];
for c in v.chars() {
match c {
'\\' => {
self.buf.push(b'\\');
self.buf.push(b'\\');
}
'"' => {
self.buf.push(b'\\');
self.buf.push(b'"');
}
'\u{0008}' => {
self.buf.push(b'\\');
self.buf.push(b'b');
}
'\u{0009}' => {
self.buf.push(b'\\');
self.buf.push(b't');
}
'\u{000A}' => {
self.buf.push(b'\\');
self.buf.push(b'n');
}
'\u{000C}' => {
self.buf.push(b'\\');
self.buf.push(b'f');
}
'\u{000D}' => {
self.buf.push(b'\\');
self.buf.push(b'r');
}
'\u{0000}'..='\u{001F}' => {
self.buf.push(b'\\');
self.buf.push(b'u');
self.buf.push(b'0');
self.buf.push(b'0');
let (hex1, hex2) = hex(c as u8);
self.buf.push(hex1);
self.buf.push(hex2);
}
_ => {
let encoded = c.encode_utf8(&mut encoding_tmp as &mut [u8]);
self.buf.extend_from_slice(encoded.as_bytes());
}
}
}
self.buf.push(b'"');
Ok(())
}
fn serialize_bytes(self, _v: &[u8]) -> Result<Self::Ok> {
unreachable!()
}
fn serialize_none(self) -> Result<Self::Ok> {
self.buf.extend_from_slice(b"null");
Ok(())
}
fn serialize_some<T: ?Sized>(self, value: &T) -> Result<Self::Ok>
where
T: ser::Serialize,
{
value.serialize(self)
}
fn serialize_unit(self) -> Result<Self::Ok> {
unreachable!()
}
fn serialize_unit_struct(self, _name: &'static str) -> Result<Self::Ok> {
unreachable!()
}
fn serialize_unit_variant(
self,
_name: &'static str,
_variant_index: u32,
variant: &'static str,
) -> Result<Self::Ok> {
self.serialize_str(variant)
}
fn serialize_newtype_struct<T: ?Sized>(self, _name: &'static str, value: &T) -> Result<Self::Ok>
where
T: ser::Serialize,
{
value.serialize(&mut *self)
}
fn serialize_newtype_variant<T: ?Sized>(
self,
_name: &'static str,
_variant_index: u32,
variant: &'static str,
value: &T,
) -> Result<Self::Ok>
where
T: ser::Serialize,
{
self.buf.push(b'{');
self.serialize_str(variant)?;
self.buf.push(b':');
value.serialize(&mut *self)?;
self.buf.push(b'}');
Ok(())
}
fn serialize_seq(self, _len: Option<usize>) -> Result<Self::SerializeSeq> {
self.buf.push(b'[');
Ok(SerializeSeq::new(self))
}
fn serialize_tuple(self, _len: usize) -> Result<Self::SerializeTuple> {
self.serialize_seq(Some(_len))
}
fn serialize_tuple_struct(
self,
_name: &'static str,
_len: usize,
) -> Result<Self::SerializeTupleStruct> {
unreachable!()
}
fn serialize_tuple_variant(
self,
_name: &'static str,
_variant_index: u32,
_variant: &'static str,
_len: usize,
) -> Result<Self::SerializeTupleVariant> {
unreachable!()
}
fn serialize_map(self, _len: Option<usize>) -> Result<Self::SerializeMap> {
unreachable!()
}
fn serialize_struct(self, _name: &'static str, _len: usize) -> Result<Self::SerializeStruct> {
self.buf.push(b'{');
Ok(SerializeStruct::new(self))
}
fn serialize_struct_variant(
self,
name: &'static str,
_variant_index: u32,
variant: &'static str,
len: usize,
) -> Result<Self::SerializeStructVariant> {
self.buf.push(b'{');
self.serialize_str(variant)?;
self.buf.push(b':');
self.serialize_struct(name, len)
}
fn collect_str<T: ?Sized>(self, _value: &T) -> Result<Self::Ok>
where
T: fmt::Display,
{
unreachable!()
}
}
pub fn to_string<T>(value: &T) -> Result<String>
where
T: ser::Serialize + ?Sized,
{
let mut ser = Serializer::new();
value.serialize(&mut ser)?;
Ok(unsafe { String::from_utf8_unchecked(ser.buf) })
}
pub fn to_vec<T>(value: &T) -> Result<Vec<u8>>
where
T: ser::Serialize + ?Sized,
{
let mut ser = Serializer::new();
value.serialize(&mut ser)?;
Ok(ser.buf)
}
impl ser::Error for Error {
fn custom<T>(msg: T) -> Self
where
T: fmt::Display,
{
Error::Custom(msg.to_string())
}
}
pub enum Unreachable {}
impl ser::SerializeTupleStruct for Unreachable {
type Ok = ();
type Error = Error;
fn serialize_field<T: ?Sized>(&mut self, _value: &T) -> Result<()> {
unreachable!()
}
fn end(self) -> Result<Self::Ok> {
unreachable!()
}
}
impl ser::SerializeTupleVariant for Unreachable {
type Ok = ();
type Error = Error;
fn serialize_field<T: ?Sized>(&mut self, _value: &T) -> Result<()> {
unreachable!()
}
fn end(self) -> Result<Self::Ok> {
unreachable!()
}
}
impl ser::SerializeMap for Unreachable {
type Ok = ();
type Error = Error;
fn serialize_key<T: ?Sized>(&mut self, _key: &T) -> Result<()>
where
T: ser::Serialize,
{
unreachable!()
}
fn serialize_value<T: ?Sized>(&mut self, _value: &T) -> Result<()>
where
T: ser::Serialize,
{
unreachable!()
}
fn end(self) -> Result<Self::Ok> {
unreachable!()
}
}
impl ser::SerializeStructVariant for Unreachable {
type Ok = ();
type Error = Error;
fn serialize_field<T: ?Sized>(&mut self, _key: &'static str, _value: &T) -> Result<()>
where
T: ser::Serialize,
{
unreachable!()
}
fn end(self) -> Result<Self::Ok> {
unreachable!()
}
}
#[cfg(test)]
mod tests {
use super::to_string;
use serde_derive::Serialize;
#[test]
fn bool() {
assert_eq!(to_string(&true).unwrap(), "true");
assert_eq!(to_string(&false).unwrap(), "false");
}
#[test]
fn number() {
assert_eq!(to_string::<u8>(&0).unwrap(), "0");
assert_eq!(to_string::<u8>(&1).unwrap(), "1");
assert_eq!(to_string::<u8>(&std::u8::MAX).unwrap(), "255");
assert_eq!(to_string::<i8>(&0).unwrap(), "0");
assert_eq!(to_string::<i8>(&1).unwrap(), "1");
assert_eq!(to_string::<i8>(&127).unwrap(), "127");
assert_eq!(to_string::<i8>(&-1).unwrap(), "-1");
assert_eq!(to_string::<i8>(&std::i8::MIN).unwrap(), "-128");
assert_eq!(to_string::<u16>(&0).unwrap(), "0");
assert_eq!(to_string::<u16>(&1).unwrap(), "1");
assert_eq!(to_string::<u16>(&550).unwrap(), "550");
assert_eq!(to_string::<u16>(&std::u16::MAX).unwrap(), "65535");
assert_eq!(to_string::<i16>(&0).unwrap(), "0");
assert_eq!(to_string::<i16>(&1).unwrap(), "1");
assert_eq!(to_string::<i16>(&550).unwrap(), "550");
assert_eq!(to_string::<i16>(&std::i16::MAX).unwrap(), "32767");
assert_eq!(to_string::<i16>(&-1).unwrap(), "-1");
assert_eq!(to_string::<i16>(&std::i16::MIN).unwrap(), "-32768");
assert_eq!(to_string::<u32>(&0).unwrap(), "0");
assert_eq!(to_string::<u32>(&1).unwrap(), "1");
assert_eq!(to_string::<u32>(&456789).unwrap(), "456789");
assert_eq!(to_string::<u32>(&std::u32::MAX).unwrap(), "4294967295");
assert_eq!(to_string::<i32>(&0).unwrap(), "0");
assert_eq!(to_string::<i32>(&1).unwrap(), "1");
assert_eq!(to_string::<i32>(&456789).unwrap(), "456789");
assert_eq!(to_string::<i32>(&std::i32::MAX).unwrap(), "2147483647");
assert_eq!(to_string::<i32>(&-1).unwrap(), "-1");
assert_eq!(to_string::<i32>(&std::i32::MIN).unwrap(), "-2147483648");
assert_eq!(to_string::<u64>(&0).unwrap(), "0");
assert_eq!(to_string::<u64>(&1).unwrap(), "1");
assert_eq!(to_string::<u64>(&456789).unwrap(), "456789");
assert_eq!(to_string::<u64>(&4294967295).unwrap(), "4294967295");
assert_eq!(to_string::<u64>(&4294967296).unwrap(), "4294967296");
assert_eq!(
to_string::<u64>(&9007199254740991).unwrap(),
"9007199254740991"
);
assert_eq!(
to_string::<u64>(&9007199254740992).unwrap(),
"9007199254740992"
);
assert_eq!(
to_string::<u64>(&std::u64::MAX).unwrap(),
"18446744073709551615"
);
assert_eq!(to_string::<i64>(&0).unwrap(), "0");
assert_eq!(to_string::<i64>(&1).unwrap(), "1");
assert_eq!(to_string::<i64>(&456789).unwrap(), "456789");
assert_eq!(to_string::<i64>(&4294967295).unwrap(), "4294967295");
assert_eq!(to_string::<i64>(&4294967296).unwrap(), "4294967296");
assert_eq!(
to_string::<i64>(&9007199254740991).unwrap(),
"9007199254740991"
);
assert_eq!(
to_string::<i64>(&9007199254740992).unwrap(),
"9007199254740992"
);
assert_eq!(
to_string::<i64>(&std::i64::MAX).unwrap(),
"9223372036854775807"
);
assert_eq!(to_string::<i64>(&-1).unwrap(), "-1");
assert_eq!(
to_string::<i64>(&std::i64::MIN).unwrap(),
"-9223372036854775808"
);
}
#[test]
fn array() {
assert_eq!(to_string::<[u8]>(&[]).unwrap(), "[]");
assert_eq!(to_string(&[0, 1, 2]).unwrap(), "[0,1,2]");
}
#[test]
fn enum_() {
#[derive(Serialize)]
enum Type {
#[serde(rename = "boolean")]
Boolean,
#[serde(rename = "number")]
Number,
}
assert_eq!(to_string(&Type::Boolean).unwrap(), r#""boolean""#);
assert_eq!(to_string(&Type::Number).unwrap(), r#""number""#);
}
#[test]
fn str() {
assert_eq!(to_string("hello").unwrap(), r#""hello""#);
assert_eq!(to_string("").unwrap(), r#""""#);
assert_eq!(to_string("ä").unwrap(), r#""ä""#);
assert_eq!(to_string("৬").unwrap(), r#""৬""#);
assert_eq!(to_string("\u{A0}").unwrap(), r#"" ""#);
assert_eq!(to_string("ℝ").unwrap(), r#""ℝ""#);
assert_eq!(to_string("💣").unwrap(), r#""💣""#);
assert_eq!(to_string("foo\"bar").unwrap(), r#""foo\"bar""#);
assert_eq!(to_string("foo\\bar").unwrap(), r#""foo\\bar""#);
assert_eq!(to_string(" \u{0008} ").unwrap(), r#"" \b ""#);
assert_eq!(to_string(" \u{0009} ").unwrap(), r#"" \t ""#);
assert_eq!(to_string(" \u{000A} ").unwrap(), r#"" \n ""#);
assert_eq!(to_string(" \u{000C} ").unwrap(), r#"" \f ""#);
assert_eq!(to_string(" \u{000D} ").unwrap(), r#"" \r ""#);
assert_eq!(to_string(" \u{0000} ").unwrap(), r#"" \u0000 ""#);
assert_eq!(to_string(" \u{0001} ").unwrap(), r#"" \u0001 ""#);
assert_eq!(to_string(" \u{0007} ").unwrap(), r#"" \u0007 ""#);
assert_eq!(to_string(" \u{000e} ").unwrap(), r#"" \u000E ""#);
assert_eq!(to_string(" \u{001D} ").unwrap(), r#"" \u001D ""#);
assert_eq!(to_string(" \u{001f} ").unwrap(), r#"" \u001F ""#);
}
#[test]
fn newtype() {
#[derive(Serialize)]
struct Address(String);
#[derive(Serialize)]
struct CommentId(u32);
assert_eq!(
to_string(&Address("home".to_string())).unwrap(),
r#""home""#
);
assert_eq!(to_string(&CommentId(42)).unwrap(), r#"42"#);
}
#[test]
fn struct_bool() {
#[derive(Serialize)]
struct Led {
led: bool,
}
assert_eq!(to_string(&Led { led: true }).unwrap(), r#"{"led":true}"#);
}
#[test]
fn struct_i8() {
#[derive(Serialize)]
struct Temperature {
temperature: i8,
}
assert_eq!(
to_string(&Temperature { temperature: 127 }).unwrap(),
r#"{"temperature":127}"#
);
assert_eq!(
to_string(&Temperature { temperature: 20 }).unwrap(),
r#"{"temperature":20}"#
);
assert_eq!(
to_string(&Temperature { temperature: -17 }).unwrap(),
r#"{"temperature":-17}"#
);
assert_eq!(
to_string(&Temperature { temperature: -128 }).unwrap(),
r#"{"temperature":-128}"#
);
}
#[test]
fn struct_option() {
#[derive(Serialize)]
struct Property<'a> {
description: Option<&'a str>,
}
assert_eq!(
to_string(&Property {
description: Some("An ambient temperature sensor"),
})
.unwrap(),
r#"{"description":"An ambient temperature sensor"}"#
);
assert_eq!(
to_string(&Property { description: None }).unwrap(),
r#"{"description":null}"#
);
}
#[test]
fn struct_u8() {
#[derive(Serialize)]
struct Temperature {
temperature: u8,
}
assert_eq!(
to_string(&Temperature { temperature: 20 }).unwrap(),
r#"{"temperature":20}"#
);
}
#[test]
fn struct_() {
#[derive(Serialize)]
struct Empty {}
assert_eq!(to_string(&Empty {}).unwrap(), r#"{}"#);
#[derive(Serialize)]
struct Tuple {
a: bool,
b: bool,
}
assert_eq!(
to_string(&Tuple { a: true, b: false }).unwrap(),
r#"{"a":true,"b":false}"#
);
}
use serde_derive::Deserialize;
#[test]
fn serialize_embedded_enum() {
#[derive(Debug, Deserialize, Serialize, PartialEq)]
#[serde(rename_all = "lowercase")]
pub enum MyResult {
Ok(Response),
Err(String),
}
#[derive(Debug, Deserialize, Serialize, PartialEq)]
pub struct Response {
pub log: Option<String>,
pub count: i64,
pub list: Vec<u32>,
}
let err_input = MyResult::Err("some error".to_string());
let json = to_string(&err_input).expect("encode err enum");
assert_eq!(json, r#"{"err":"some error"}"#.to_string());
let loaded = crate::from_str(&json).expect("re-load err enum");
assert_eq!(err_input, loaded);
let empty_list = MyResult::Ok(Response {
log: Some("log message".to_string()),
count: 137,
list: Vec::new(),
});
let json = to_string(&empty_list).expect("encode ok enum");
assert_eq!(
json,
r#"{"ok":{"log":"log message","count":137,"list":[]}}"#.to_string()
);
let loaded = crate::from_str(&json).expect("re-load ok enum");
assert_eq!(empty_list, loaded);
let full_list = MyResult::Ok(Response {
log: None,
count: 137,
list: vec![18u32, 34, 12],
});
let json = to_string(&full_list).expect("encode ok enum");
assert_eq!(
json,
r#"{"ok":{"log":null,"count":137,"list":[18,34,12]}}"#.to_string()
);
let loaded = crate::from_str(&json).expect("re-load ok enum");
assert_eq!(full_list, loaded);
}
}