Introduce serde_v8 (#9722)

1 files changed, 484 insertions, 0 deletions

diff --git a/serde_v8/src/de.rs b/serde_v8/src/de.rs
new file mode 100644
index 000000000..22d66f7ce
--- /dev/null
+++ b/serde_v8/src/de.rs
@@ -0,0 +1,484 @@
+use rusty_v8 as v8;
+use serde::de::{self, Visitor};
+use serde::Deserialize;
+
+use std::convert::TryFrom;
+
+use crate::error::{Error, Result};
+use crate::keys::{v8_struct_key, KeyCache};
+use crate::payload::ValueType;
+
+use crate::magic;
+
+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 $method<V>(self, _v: V) -> Result<V::Value>
+    where
+      V: Visitor<'de>,
+    {
+      unimplemented!()
+    }
+  };
+}
+
+macro_rules! deserialize_signed {
+  ($dmethod:ident, $vmethod:ident, $t:tt) => {
+    fn $dmethod<V>(self, visitor: V) -> Result<V::Value>
+    where
+      V: Visitor<'de>,
+    {
+      visitor.$vmethod(self.input.integer_value(&mut self.scope).unwrap() as $t)
+    }
+  };
+}
+
+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),
+      ValueType::Number => self.deserialize_f64(visitor),
+      ValueType::String => self.deserialize_string(visitor),
+      ValueType::Array => self.deserialize_seq(visitor),
+      ValueType::Object => self.deserialize_map(visitor),
+    }
+  }
+
+  fn deserialize_bool<V>(self, visitor: V) -> Result<V::Value>
+  where
+    V: Visitor<'de>,
+  {
+    if self.input.is_boolean() {
+      visitor.visit_bool(self.input.boolean_value(&mut self.scope))
+    } else {
+      Err(Error::ExpectedBoolean)
+    }
+  }
+
+  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);
+  // TODO: maybe handle unsigned by itself ?
+  deserialize_signed!(deserialize_u8, visit_u8, u8);
+  deserialize_signed!(deserialize_u16, visit_u16, u16);
+  deserialize_signed!(deserialize_u32, visit_u32, u32);
+  deserialize_signed!(deserialize_u64, visit_u64, u64);
+
+  fn deserialize_f32<V>(self, visitor: V) -> Result<V::Value>
+  where
+    V: Visitor<'de>,
+  {
+    visitor.visit_f32(self.input.number_value(&mut self.scope).unwrap() as f32)
+  }
+
+  fn deserialize_f64<V>(self, visitor: V) -> Result<V::Value>
+  where
+    V: Visitor<'de>,
+  {
+    visitor.visit_f64(self.input.number_value(&mut self.scope).unwrap())
+  }
+
+  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 string = self.input.to_rust_string_lossy(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>,
+  {
+    if self.input.is_null_or_undefined() {
+      visitor.visit_unit()
+    } else {
+      Err(Error::ExpectedNull)
+    }
+  }
+
+  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).unwrap();
+    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).unwrap();
+    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()).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>,
+  {
+    // Magic for serde_v8::magic::Value, to passthrough v8::Value
+    // TODO: ensure this is cross-platform and there's no alternative
+    if name == magic::NAME {
+      let mv = magic::Value {
+        v8_value: self.input,
+      };
+      let hack: u64 = unsafe { std::mem::transmute(mv) };
+      return visitor.visit_u64(hack);
+    }
+
+    // Regular struct
+    let obj = v8::Local::<v8::Object>::try_from(self.input).unwrap();
+    let map = ObjectAccess {
+      fields,
+      obj,
+      pos: 0,
+      scope: self.scope,
+      _cache: None,
+    };
+
+    visitor.visit_map(map)
+  }
+
+  fn deserialize_enum<V>(
+    self,
+    _name: &str,
+    _variants: &'static [&'static str],
+    _visitor: V,
+  ) -> Result<V::Value>
+  where
+    V: Visitor<'de>,
+  {
+    unimplemented!();
+  }
+
+  // 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 ObjectAccess<'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>,
+}
+
+fn str_deserializer(s: &str) -> de::value::StrDeserializer<Error> {
+  de::IntoDeserializer::into_deserializer(s)
+}
+
+impl<'de, 'a, 'b, 's> de::MapAccess<'de> for ObjectAccess<'a, 'b, 's> {
+  type Error = Error;
+
+  fn next_key_seed<K: de::DeserializeSeed<'de>>(
+    &mut self,
+    seed: K,
+  ) -> Result<Option<K::Value>> {
+    Ok(match self.fields.get(self.pos) {
+      Some(&field) => Some(seed.deserialize(str_deserializer(field))?),
+      None => None,
+    })
+  }
+
+  fn next_value_seed<V: de::DeserializeSeed<'de>>(
+    &mut self,
+    seed: V,
+  ) -> Result<V::Value> {
+    if self.pos >= self.fields.len() {
+      return Err(Error::LengthMismatch);
+    }
+    let field = self.fields[self.pos];
+    self.pos += 1;
+    let key = v8_struct_key(self.scope, field).into();
+    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.fields.len() {
+      return Ok(None);
+    }
+    let field = self.fields[self.pos];
+    self.pos += 1;
+    Ok(Some((kseed.deserialize(str_deserializer(field))?, {
+      let key = v8_struct_key(self.scope, field).into();
+      let v8_val = self.obj.get(self.scope, key).unwrap();
+      let mut deserializer = Deserializer::new(self.scope, v8_val, None);
+      vseed.deserialize(&mut deserializer)?
+    })))
+  }
+}
+
+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)
+    }
+  }
+}