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denoland-deno/serde_v8/de.rs
2022-05-15 17:16:09 +02:00

726 lines
20 KiB
Rust

// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
use serde::de::{self, Visitor};
use serde::Deserialize;
use crate::error::{Error, Result};
use crate::keys::{v8_struct_key, KeyCache};
use crate::magic::transl8::FromV8;
use crate::magic::transl8::{visit_magic, MagicType};
use crate::payload::ValueType;
use crate::{
magic, ByteString, DetachedBuffer, StringOrBuffer, U16String, ZeroCopyBuf,
};
pub struct Deserializer<'a, 'b, 's> {
input: v8::Local<'a, v8::Value>,
scope: &'b mut v8::HandleScope<'s>,
_key_cache: Option<&'b mut KeyCache>,
}
impl<'a, 'b, 's> Deserializer<'a, 'b, 's> {
pub fn new(
scope: &'b mut v8::HandleScope<'s>,
input: v8::Local<'a, v8::Value>,
key_cache: Option<&'b mut KeyCache>,
) -> Self {
Deserializer {
input,
scope,
_key_cache: key_cache,
}
}
}
// from_v8 deserializes a v8::Value into a Deserializable / rust struct
pub fn from_v8<'de, 'a, 'b, 's, T>(
scope: &'b mut v8::HandleScope<'s>,
input: v8::Local<'a, v8::Value>,
) -> Result<T>
where
T: Deserialize<'de>,
{
let mut deserializer = Deserializer::new(scope, input, None);
let t = T::deserialize(&mut deserializer)?;
Ok(t)
}
// like from_v8 except accepts a KeyCache to optimize struct key decoding
pub fn from_v8_cached<'de, 'a, 'b, 's, T>(
scope: &'b mut v8::HandleScope<'s>,
input: v8::Local<'a, v8::Value>,
key_cache: &mut KeyCache,
) -> Result<T>
where
T: Deserialize<'de>,
{
let mut deserializer = Deserializer::new(scope, input, Some(key_cache));
let t = T::deserialize(&mut deserializer)?;
Ok(t)
}
macro_rules! wip {
($method:ident) => {
fn $method<V>(self, _v: V) -> Result<V::Value>
where
V: Visitor<'de>,
{
unimplemented!()
}
};
}
// TODO: maybe check for BigInt truncation ?
// (i.e: values larger than i64/u64 can hold)
macro_rules! deserialize_signed {
($dmethod:ident, $vmethod:ident, $t:tt) => {
fn $dmethod<V>(self, visitor: V) -> Result<V::Value>
where
V: Visitor<'de>,
{
visitor.$vmethod(
if let Ok(x) = v8::Local::<v8::Number>::try_from(self.input) {
x.value() as $t
} else if let Ok(x) = v8::Local::<v8::BigInt>::try_from(self.input) {
x.i64_value().0 as $t
} else if let Some(x) = self.input.number_value(self.scope) {
x as $t
} else if let Some(x) = self.input.to_big_int(self.scope) {
x.i64_value().0 as $t
} else {
return Err(Error::ExpectedInteger);
},
)
}
};
}
macro_rules! deserialize_unsigned {
($dmethod:ident, $vmethod:ident, $t:tt) => {
fn $dmethod<V>(self, visitor: V) -> Result<V::Value>
where
V: Visitor<'de>,
{
visitor.$vmethod(
if let Ok(x) = v8::Local::<v8::Number>::try_from(self.input) {
x.value() as $t
} else if let Ok(x) = v8::Local::<v8::BigInt>::try_from(self.input) {
x.u64_value().0 as $t
} else if let Some(x) = self.input.number_value(self.scope) {
x as $t
} else if let Some(x) = self.input.to_big_int(self.scope) {
x.u64_value().0 as $t
} else {
return Err(Error::ExpectedInteger);
},
)
}
};
}
impl<'de, 'a, 'b, 's, 'x> de::Deserializer<'de>
for &'x mut Deserializer<'a, 'b, 's>
{
type Error = Error;
fn deserialize_any<V>(self, visitor: V) -> Result<V::Value>
where
V: Visitor<'de>,
{
match ValueType::from_v8(self.input) {
ValueType::Null => self.deserialize_unit(visitor),
ValueType::Bool => self.deserialize_bool(visitor),
// Handle floats & ints separately to work with loosely-typed serde_json
ValueType::Number => {
if self.input.is_uint32() {
self.deserialize_u32(visitor)
} else if self.input.is_int32() {
self.deserialize_i32(visitor)
} else {
self.deserialize_f64(visitor)
}
}
ValueType::String => self.deserialize_string(visitor),
ValueType::Array => self.deserialize_seq(visitor),
ValueType::Object => self.deserialize_map(visitor),
// Map to Vec<u8> when deserialized via deserialize_any
// e.g: for untagged enums or StringOrBuffer
ValueType::ArrayBufferView | ValueType::ArrayBuffer => {
magic::v8slice::V8Slice::from_v8(&mut *self.scope, self.input)
.and_then(|zb| visitor.visit_byte_buf(Vec::from(&*zb)))
}
}
}
fn deserialize_bool<V>(self, visitor: V) -> Result<V::Value>
where
V: Visitor<'de>,
{
// Relaxed typechecking, will map all non-true vals to false
visitor.visit_bool(self.input.is_true())
}
// signed
deserialize_signed!(deserialize_i8, visit_i8, i8);
deserialize_signed!(deserialize_i16, visit_i16, i16);
deserialize_signed!(deserialize_i32, visit_i32, i32);
deserialize_signed!(deserialize_i64, visit_i64, i64);
// unsigned
deserialize_unsigned!(deserialize_u8, visit_u8, u8);
deserialize_unsigned!(deserialize_u16, visit_u16, u16);
deserialize_unsigned!(deserialize_u32, visit_u32, u32);
deserialize_unsigned!(deserialize_u64, visit_u64, u64);
fn deserialize_f32<V>(self, visitor: V) -> Result<V::Value>
where
V: Visitor<'de>,
{
self.deserialize_f64(visitor)
}
fn deserialize_f64<V>(self, visitor: V) -> Result<V::Value>
where
V: Visitor<'de>,
{
visitor.visit_f64(
if let Ok(x) = v8::Local::<v8::Number>::try_from(self.input) {
x.value() as f64
} else if let Ok(x) = v8::Local::<v8::BigInt>::try_from(self.input) {
bigint_to_f64(x)
} else if let Some(x) = self.input.number_value(self.scope) {
x as f64
} else if let Some(x) = self.input.to_big_int(self.scope) {
bigint_to_f64(x)
} else {
return Err(Error::ExpectedNumber);
},
)
}
wip!(deserialize_char);
fn deserialize_str<V>(self, visitor: V) -> Result<V::Value>
where
V: Visitor<'de>,
{
self.deserialize_string(visitor)
}
fn deserialize_string<V>(self, visitor: V) -> Result<V::Value>
where
V: Visitor<'de>,
{
if self.input.is_string() {
let v8_string = v8::Local::<v8::String>::try_from(self.input).unwrap();
let string = to_utf8(v8_string, self.scope);
visitor.visit_string(string)
} else {
Err(Error::ExpectedString)
}
}
wip!(deserialize_bytes);
wip!(deserialize_byte_buf);
fn deserialize_option<V>(self, visitor: V) -> Result<V::Value>
where
V: Visitor<'de>,
{
if self.input.is_null_or_undefined() {
visitor.visit_none()
} else {
visitor.visit_some(self)
}
}
fn deserialize_unit<V>(self, visitor: V) -> Result<V::Value>
where
V: Visitor<'de>,
{
visitor.visit_unit()
}
fn deserialize_unit_struct<V>(
self,
_name: &'static str,
visitor: V,
) -> Result<V::Value>
where
V: Visitor<'de>,
{
self.deserialize_unit(visitor)
}
// As is done here, serializers are encouraged to treat newtype structs as
// insignificant wrappers around the data they contain. That means not
// parsing anything other than the contained value.
fn deserialize_newtype_struct<V>(
self,
_name: &'static str,
visitor: V,
) -> Result<V::Value>
where
V: Visitor<'de>,
{
visitor.visit_newtype_struct(self)
}
fn deserialize_seq<V>(self, visitor: V) -> Result<V::Value>
where
V: Visitor<'de>,
{
let arr = v8::Local::<v8::Array>::try_from(self.input)
.map_err(|_| Error::ExpectedArray)?;
let len = arr.length();
let obj = v8::Local::<v8::Object>::from(arr);
let seq = SeqAccess {
pos: 0,
len,
obj,
scope: self.scope,
};
visitor.visit_seq(seq)
}
// Like deserialize_seq except it prefers tuple's length over input array's length
fn deserialize_tuple<V>(self, len: usize, visitor: V) -> Result<V::Value>
where
V: Visitor<'de>,
{
// TODO: error on length mismatch
let obj = v8::Local::<v8::Object>::try_from(self.input).unwrap();
let seq = SeqAccess {
pos: 0,
len: len as u32,
obj,
scope: self.scope,
};
visitor.visit_seq(seq)
}
// Tuple structs look just like sequences in JSON.
fn deserialize_tuple_struct<V>(
self,
_name: &'static str,
len: usize,
visitor: V,
) -> Result<V::Value>
where
V: Visitor<'de>,
{
self.deserialize_tuple(len, visitor)
}
fn deserialize_map<V>(self, visitor: V) -> Result<V::Value>
where
V: de::Visitor<'de>,
{
// Assume object, then get_own_property_names
let obj = v8::Local::<v8::Object>::try_from(self.input)
.map_err(|_| Error::ExpectedObject)?;
let prop_names = obj.get_own_property_names(self.scope);
let mut keys: Vec<magic::Value> = match prop_names {
Some(names) => from_v8(self.scope, names.into()).unwrap(),
None => vec![],
};
let keys: Vec<v8::Local<v8::Value>> = keys
.drain(..)
.map(|x| x.into())
// Filter keys to drop keys whose value is undefined
// TODO: optimize, since this doubles our get calls
.filter(|key| !obj.get(self.scope, *key).unwrap().is_undefined())
.collect();
let map = MapAccess {
obj,
keys,
pos: 0,
scope: self.scope,
};
visitor.visit_map(map)
}
fn deserialize_struct<V>(
self,
name: &'static str,
fields: &'static [&'static str],
visitor: V,
) -> Result<V::Value>
where
V: Visitor<'de>,
{
match name {
ZeroCopyBuf::MAGIC_NAME => {
visit_magic(visitor, ZeroCopyBuf::from_v8(self.scope, self.input)?)
}
DetachedBuffer::MAGIC_NAME => {
visit_magic(visitor, DetachedBuffer::from_v8(self.scope, self.input)?)
}
ByteString::MAGIC_NAME => {
visit_magic(visitor, ByteString::from_v8(self.scope, self.input)?)
}
U16String::MAGIC_NAME => {
visit_magic(visitor, U16String::from_v8(self.scope, self.input)?)
}
StringOrBuffer::MAGIC_NAME => {
visit_magic(visitor, StringOrBuffer::from_v8(self.scope, self.input)?)
}
magic::Value::MAGIC_NAME => {
visit_magic(visitor, magic::Value::from_v8(self.scope, self.input)?)
}
_ => {
// Regular struct
let obj = self.input.try_into().or(Err(Error::ExpectedObject))?;
visitor.visit_seq(StructAccess {
fields,
obj,
pos: 0,
scope: self.scope,
_cache: None,
})
}
}
}
/// To be compatible with `serde-json`, we expect enums to be:
/// - `"Variant"`: strings for unit variants, i.e: Enum::Variant
/// - `{ Variant: payload }`: single K/V pairs, converted to `Enum::Variant { payload }`
fn deserialize_enum<V>(
self,
_name: &str,
_variants: &'static [&'static str],
visitor: V,
) -> Result<V::Value>
where
V: Visitor<'de>,
{
// Unit variant
if self.input.is_string() {
let payload = v8::undefined(self.scope).into();
visitor.visit_enum(EnumAccess {
scope: self.scope,
tag: self.input,
payload,
})
}
// Struct or tuple variant
else if self.input.is_object() {
// Assume object
let obj = v8::Local::<v8::Object>::try_from(self.input).unwrap();
// Unpack single-key
let tag = {
let prop_names = obj.get_own_property_names(self.scope);
let prop_names = prop_names.ok_or(Error::ExpectedEnum)?;
if prop_names.length() != 1 {
return Err(Error::LengthMismatch);
}
prop_names.get_index(self.scope, 0).unwrap()
};
let payload = obj.get(self.scope, tag).unwrap();
visitor.visit_enum(EnumAccess {
scope: self.scope,
tag,
payload,
})
} else {
// TODO: improve error
Err(Error::ExpectedEnum)
}
}
// An identifier in Serde is the type that identifies a field of a struct or
// the variant of an enum. In JSON, struct fields and enum variants are
// represented as strings. In other formats they may be represented as
// numeric indices.
fn deserialize_identifier<V>(self, visitor: V) -> Result<V::Value>
where
V: Visitor<'de>,
{
self.deserialize_str(visitor)
}
fn deserialize_ignored_any<V>(self, visitor: V) -> Result<V::Value>
where
V: Visitor<'de>,
{
visitor.visit_none()
}
}
struct MapAccess<'a, 'b, 's> {
obj: v8::Local<'a, v8::Object>,
scope: &'b mut v8::HandleScope<'s>,
keys: Vec<v8::Local<'a, v8::Value>>,
pos: usize,
}
impl<'de> de::MapAccess<'de> for MapAccess<'_, '_, '_> {
type Error = Error;
fn next_key_seed<K: de::DeserializeSeed<'de>>(
&mut self,
seed: K,
) -> Result<Option<K::Value>> {
Ok(match self.keys.get(self.pos) {
Some(key) => {
let mut deserializer = Deserializer::new(self.scope, *key, None);
Some(seed.deserialize(&mut deserializer)?)
}
None => None,
})
}
fn next_value_seed<V: de::DeserializeSeed<'de>>(
&mut self,
seed: V,
) -> Result<V::Value> {
if self.pos >= self.keys.len() {
return Err(Error::LengthMismatch);
}
let key = self.keys[self.pos];
self.pos += 1;
let v8_val = self.obj.get(self.scope, key).unwrap();
let mut deserializer = Deserializer::new(self.scope, v8_val, None);
seed.deserialize(&mut deserializer)
}
fn next_entry_seed<
K: de::DeserializeSeed<'de>,
V: de::DeserializeSeed<'de>,
>(
&mut self,
kseed: K,
vseed: V,
) -> Result<Option<(K::Value, V::Value)>> {
if self.pos >= self.keys.len() {
return Ok(None);
}
let v8_key = self.keys[self.pos];
self.pos += 1;
let mut kdeserializer = Deserializer::new(self.scope, v8_key, None);
Ok(Some((kseed.deserialize(&mut kdeserializer)?, {
let v8_val = self.obj.get(self.scope, v8_key).unwrap();
let mut deserializer = Deserializer::new(self.scope, v8_val, None);
vseed.deserialize(&mut deserializer)?
})))
}
}
struct StructAccess<'a, 'b, 's> {
obj: v8::Local<'a, v8::Object>,
scope: &'b mut v8::HandleScope<'s>,
fields: &'static [&'static str],
pos: usize,
_cache: Option<&'b mut KeyCache>,
}
impl<'de> de::SeqAccess<'de> for StructAccess<'_, '_, '_> {
type Error = Error;
fn next_element_seed<T: de::DeserializeSeed<'de>>(
&mut self,
seed: T,
) -> Result<Option<T::Value>> {
if self.pos >= self.fields.len() {
return Ok(None);
}
let pos = self.pos;
self.pos += 1;
let field = self.fields[pos];
let key = v8_struct_key(self.scope, field).into();
let val = self.obj.get(self.scope, key).unwrap();
let mut deserializer = Deserializer::new(self.scope, val, None);
match seed.deserialize(&mut deserializer) {
Ok(val) => Ok(Some(val)),
// Fallback to Ok(None) for #[serde(Default)] at cost of error quality ...
// TODO(@AaronO): double check that there's no better solution
Err(_) if val.is_undefined() => Ok(None),
Err(e) => Err(e),
}
}
}
struct SeqAccess<'a, 'b, 's> {
obj: v8::Local<'a, v8::Object>,
scope: &'b mut v8::HandleScope<'s>,
len: u32,
pos: u32,
}
impl<'de> de::SeqAccess<'de> for SeqAccess<'_, '_, '_> {
type Error = Error;
fn next_element_seed<T: de::DeserializeSeed<'de>>(
&mut self,
seed: T,
) -> Result<Option<T::Value>> {
let pos = self.pos;
self.pos += 1;
if pos < self.len {
let val = self.obj.get_index(self.scope, pos).unwrap();
let mut deserializer = Deserializer::new(self.scope, val, None);
Ok(Some(seed.deserialize(&mut deserializer)?))
} else {
Ok(None)
}
}
fn size_hint(&self) -> Option<usize> {
Some((self.len - self.pos) as usize)
}
}
struct EnumAccess<'a, 'b, 's> {
tag: v8::Local<'a, v8::Value>,
payload: v8::Local<'a, v8::Value>,
scope: &'b mut v8::HandleScope<'s>,
// p1: std::marker::PhantomData<&'x ()>,
}
impl<'de, 'a, 'b, 's, 'x> de::EnumAccess<'de> for EnumAccess<'a, 'b, 's> {
type Error = Error;
type Variant = VariantDeserializer<'a, 'b, 's>;
fn variant_seed<V: de::DeserializeSeed<'de>>(
self,
seed: V,
) -> Result<(V::Value, Self::Variant)> {
let seed = {
let mut dtag = Deserializer::new(self.scope, self.tag, None);
seed.deserialize(&mut dtag)
};
let dpayload = VariantDeserializer::<'a, 'b, 's> {
scope: self.scope,
value: self.payload,
};
Ok((seed?, dpayload))
}
}
struct VariantDeserializer<'a, 'b, 's> {
value: v8::Local<'a, v8::Value>,
scope: &'b mut v8::HandleScope<'s>,
}
impl<'de, 'a, 'b, 's> de::VariantAccess<'de>
for VariantDeserializer<'a, 'b, 's>
{
type Error = Error;
fn unit_variant(self) -> Result<()> {
let mut d = Deserializer::new(self.scope, self.value, None);
de::Deserialize::deserialize(&mut d)
}
fn newtype_variant_seed<T: de::DeserializeSeed<'de>>(
self,
seed: T,
) -> Result<T::Value> {
let mut d = Deserializer::new(self.scope, self.value, None);
seed.deserialize(&mut d)
}
fn tuple_variant<V: de::Visitor<'de>>(
self,
len: usize,
visitor: V,
) -> Result<V::Value> {
let mut d = Deserializer::new(self.scope, self.value, None);
de::Deserializer::deserialize_tuple(&mut d, len, visitor)
}
fn struct_variant<V: de::Visitor<'de>>(
self,
fields: &'static [&'static str],
visitor: V,
) -> Result<V::Value> {
let mut d = Deserializer::new(self.scope, self.value, None);
de::Deserializer::deserialize_struct(&mut d, "", fields, visitor)
}
}
fn bigint_to_f64(b: v8::Local<v8::BigInt>) -> f64 {
// log2(f64::MAX) == log2(1.7976931348623157e+308) == 1024
let mut words: [u64; 16] = [0; 16]; // 1024/64 => 16 64bit words
let (neg, words) = b.to_words_array(&mut words);
if b.word_count() > 16 {
return match neg {
true => f64::NEG_INFINITY,
false => f64::INFINITY,
};
}
let sign = if neg { -1.0 } else { 1.0 };
let x: f64 = words
.iter()
.enumerate()
.map(|(i, w)| (*w as f64) * 2.0f64.powi(64 * i as i32))
.sum();
sign * x
}
pub fn to_utf8(
s: v8::Local<v8::String>,
scope: &mut v8::HandleScope,
) -> String {
to_utf8_fast(s, scope).unwrap_or_else(|| to_utf8_slow(s, scope))
}
fn to_utf8_fast(
s: v8::Local<v8::String>,
scope: &mut v8::HandleScope,
) -> Option<String> {
// Over-allocate by 20% to avoid checking string twice
let len = s.length();
let capacity = (len as f64 * 1.2) as usize;
let mut buf = Vec::with_capacity(capacity);
let mut nchars = 0;
let data = buf.as_mut_ptr();
let length = s.write_utf8(
scope,
// SAFETY: we're essentially providing the raw internal slice/buffer owned by the Vec
// which fulfills all of from_raw_parts_mut's safety requirements besides "initialization"
// and since we're operating on a [u8] not [T] we can safely assume the slice's values
// are sufficiently "initialized" for writes
unsafe { std::slice::from_raw_parts_mut(data, capacity) },
Some(&mut nchars),
v8::WriteOptions::NO_NULL_TERMINATION
| v8::WriteOptions::REPLACE_INVALID_UTF8,
);
if nchars < len {
return None;
}
// SAFETY: write_utf8 guarantees `length` bytes are initialized & valid utf8
unsafe {
buf.set_len(length);
Some(String::from_utf8_unchecked(buf))
}
}
fn to_utf8_slow(
s: v8::Local<v8::String>,
scope: &mut v8::HandleScope,
) -> String {
let capacity = s.utf8_length(scope);
let mut buf = Vec::with_capacity(capacity);
let data = buf.as_mut_ptr();
let length = s.write_utf8(
scope,
// SAFETY: we're essentially providing the raw internal slice/buffer owned by the Vec
// which fulfills all of from_raw_parts_mut's safety requirements besides "initialization"
// and since we're operating on a [u8] not [T] we can safely assume the slice's values
// are sufficiently "initialized" for writes
unsafe { std::slice::from_raw_parts_mut(data, capacity) },
None,
v8::WriteOptions::NO_NULL_TERMINATION
| v8::WriteOptions::REPLACE_INVALID_UTF8,
);
// SAFETY: write_utf8 guarantees `length` bytes are initialized & valid utf8
unsafe {
buf.set_len(length);
String::from_utf8_unchecked(buf)
}
}