serde_view 0.1.6

use super::{View, ViewContext, ViewFields};
use serde::{ser::SerializeStruct, Serialize, Serializer};
use std::{collections::HashSet, marker::PhantomData};

pub struct ViewSerializer<'f, S, V>
where
    S: Serializer,
    V: View,
{
    serializer: S,
    fields: &'f HashSet<V::Fields>,
    _marker: PhantomData<V>,
}

/// Check if a field is needed for serialization
fn is_needed<V: View>(name: &str, fields: &HashSet<V::Fields>) -> bool {
    if fields.is_empty() {
        // if no fields are listed, we accept all
        return true;
    }

    if let Ok(field) = V::Fields::from_str(name) {
        fields.contains(&field)
    } else {
        false
    }
}

pub struct ViewSerializeStruct<'f, S, V>
where
    S: SerializeStruct,
    V: View,
{
    fields: &'f HashSet<V::Fields>,
    serializer: S,
    _marker: PhantomData<V>,
}

impl<S, V> SerializeStruct for ViewSerializeStruct<'_, S, V>
where
    S: SerializeStruct,
    V: View,
{
    type Ok = S::Ok;
    type Error = S::Error;

    fn serialize_field<T: ?Sized>(
        &mut self,
        key: &'static str,
        value: &T,
    ) -> Result<(), Self::Error>
    where
        T: Serialize,
    {
        if is_needed::<V>(key, self.fields) {
            self.serializer.serialize_field(key, value)
        } else {
            self.serializer.skip_field(key)
        }
    }

    fn skip_field(&mut self, key: &'static str) -> Result<(), Self::Error> {
        self.serializer.skip_field(key)
    }

    fn end(self) -> Result<Self::Ok, Self::Error> {
        self.serializer.end()
    }
}

impl<'f, S, V> Serializer for ViewSerializer<'f, S, V>
where
    S: Serializer,
    V: View,
{
    type Ok = S::Ok;
    type Error = S::Error;
    type SerializeSeq = S::SerializeSeq;
    type SerializeTuple = S::SerializeTuple;
    type SerializeTupleStruct = S::SerializeTupleStruct;
    type SerializeTupleVariant = S::SerializeTupleVariant;
    type SerializeMap = S::SerializeMap;
    type SerializeStruct = ViewSerializeStruct<'f, S::SerializeStruct, V>;
    type SerializeStructVariant = S::SerializeStructVariant;

    fn serialize_bool(self, v: bool) -> Result<Self::Ok, Self::Error> {
        self.serializer.serialize_bool(v)
    }

    fn serialize_i8(self, v: i8) -> Result<Self::Ok, Self::Error> {
        self.serializer.serialize_i8(v)
    }

    fn serialize_i16(self, v: i16) -> Result<Self::Ok, Self::Error> {
        self.serializer.serialize_i16(v)
    }

    fn serialize_i32(self, v: i32) -> Result<Self::Ok, Self::Error> {
        self.serializer.serialize_i32(v)
    }

    fn serialize_i64(self, v: i64) -> Result<Self::Ok, Self::Error> {
        self.serializer.serialize_i64(v)
    }

    fn serialize_u8(self, v: u8) -> Result<Self::Ok, Self::Error> {
        self.serializer.serialize_u8(v)
    }

    fn serialize_u16(self, v: u16) -> Result<Self::Ok, Self::Error> {
        self.serializer.serialize_u16(v)
    }

    fn serialize_u32(self, v: u32) -> Result<Self::Ok, Self::Error> {
        self.serializer.serialize_u32(v)
    }

    fn serialize_u64(self, v: u64) -> Result<Self::Ok, Self::Error> {
        self.serializer.serialize_u64(v)
    }

    fn serialize_f32(self, v: f32) -> Result<Self::Ok, Self::Error> {
        self.serializer.serialize_f32(v)
    }

    fn serialize_f64(self, v: f64) -> Result<Self::Ok, Self::Error> {
        self.serializer.serialize_f64(v)
    }

    fn serialize_char(self, v: char) -> Result<Self::Ok, Self::Error> {
        self.serializer.serialize_char(v)
    }

    fn serialize_str(self, v: &str) -> Result<Self::Ok, Self::Error> {
        self.serializer.serialize_str(v)
    }

    fn serialize_bytes(self, v: &[u8]) -> Result<Self::Ok, Self::Error> {
        self.serializer.serialize_bytes(v)
    }

    fn serialize_none(self) -> Result<Self::Ok, Self::Error> {
        self.serializer.serialize_none()
    }

    fn serialize_some<T: ?Sized>(self, value: &T) -> Result<Self::Ok, Self::Error>
    where
        T: Serialize,
    {
        self.serializer.serialize_some(value)
    }

    fn serialize_unit(self) -> Result<Self::Ok, Self::Error> {
        self.serializer.serialize_unit()
    }

    fn serialize_unit_struct(self, name: &'static str) -> Result<Self::Ok, Self::Error> {
        self.serializer.serialize_unit_struct(name)
    }

    fn serialize_unit_variant(
        self,
        name: &'static str,
        variant_index: u32,
        variant: &'static str,
    ) -> Result<Self::Ok, Self::Error> {
        self.serializer
            .serialize_unit_variant(name, variant_index, variant)
    }

    fn serialize_newtype_struct<T: ?Sized>(
        self,
        name: &'static str,
        value: &T,
    ) -> Result<Self::Ok, Self::Error>
    where
        T: Serialize,
    {
        self.serializer.serialize_newtype_struct(name, value)
    }

    fn serialize_newtype_variant<T: ?Sized>(
        self,
        name: &'static str,
        variant_index: u32,
        variant: &'static str,
        value: &T,
    ) -> Result<Self::Ok, Self::Error>
    where
        T: Serialize,
    {
        self.serializer
            .serialize_newtype_variant(name, variant_index, variant, value)
    }

    fn serialize_seq(self, len: Option<usize>) -> Result<Self::SerializeSeq, Self::Error> {
        self.serializer.serialize_seq(len)
    }

    fn serialize_tuple(self, len: usize) -> Result<Self::SerializeTuple, Self::Error> {
        self.serializer.serialize_tuple(len)
    }

    fn serialize_tuple_struct(
        self,
        name: &'static str,
        len: usize,
    ) -> Result<Self::SerializeTupleStruct, Self::Error> {
        self.serializer.serialize_tuple_struct(name, len)
    }

    fn serialize_tuple_variant(
        self,
        name: &'static str,
        variant_index: u32,
        variant: &'static str,
        len: usize,
    ) -> Result<Self::SerializeTupleVariant, Self::Error> {
        self.serializer
            .serialize_tuple_variant(name, variant_index, variant, len)
    }

    fn serialize_map(self, len: Option<usize>) -> Result<Self::SerializeMap, Self::Error> {
        self.serializer.serialize_map(len)
    }

    fn serialize_struct(
        self,
        name: &'static str,
        len: usize,
    ) -> Result<Self::SerializeStruct, Self::Error> {
        Ok(ViewSerializeStruct {
            serializer: self.serializer.serialize_struct(name, len)?,
            fields: self.fields,
            _marker: Default::default(),
        })
    }

    fn serialize_struct_variant(
        self,
        name: &'static str,
        variant_index: u32,
        variant: &'static str,
        len: usize,
    ) -> Result<Self::SerializeStructVariant, Self::Error> {
        self.serializer
            .serialize_struct_variant(name, variant_index, variant, len)
    }
}

impl<'v, T> Serialize for ViewContext<'v, T>
where
    T: View,
{
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: Serializer,
    {
        self.inner.serialize(ViewSerializer::<_, T> {
            serializer,
            fields: &self.fields,
            _marker: Default::default(),
        })
    }
}