gstreamer-rs/gstreamer/src/caps_features_serde.rs
2019-03-07 14:05:35 +02:00

166 lines
5.4 KiB
Rust

// Copyright (C) 2018 Sebastian Dröge <sebastian@centricular.com>
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use serde::de;
use serde::de::{Deserialize, Deserializer, EnumAccess, SeqAccess, VariantAccess, Visitor};
use serde::ser::{Serialize, SerializeSeq, Serializer};
use std::fmt;
use CapsFeatures;
use CapsFeaturesRef;
enum CapsFeaturesVariantKinds {
Any,
Some,
}
const CAPS_FEATURES_VARIANT_ANY_ID: u32 = 0;
const CAPS_FEATURES_VARIANT_ANY_STR: &str = "Any";
const CAPS_FEATURES_VARIANT_SOME_ID: u32 = 1;
const CAPS_FEATURES_VARIANT_SOME_STR: &str = "Some";
const CAPS_FEATURES_VARIANT_NAMES: &[&str] = &[
&CAPS_FEATURES_VARIANT_ANY_STR,
&CAPS_FEATURES_VARIANT_SOME_STR,
];
struct CapsFeaturesForIterSe<'a>(&'a CapsFeaturesRef);
impl<'a> Serialize for CapsFeaturesForIterSe<'a> {
fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
let iter = self.0.iter();
let size = iter.size_hint().0;
if size > 0 {
let mut seq = serializer.serialize_seq(Some(size))?;
for feature in iter {
seq.serialize_element(feature)?;
}
seq.end()
} else {
let seq = serializer.serialize_seq(None)?;
seq.end()
}
}
}
impl Serialize for CapsFeaturesRef {
fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
if self.is_any() {
serializer.serialize_unit_variant(
stringify!(CapsFeatures),
CAPS_FEATURES_VARIANT_ANY_ID,
CAPS_FEATURES_VARIANT_ANY_STR,
)
} else {
serializer.serialize_newtype_variant(
stringify!(CapsFeatures),
CAPS_FEATURES_VARIANT_SOME_ID,
CAPS_FEATURES_VARIANT_SOME_STR,
&CapsFeaturesForIterSe(&self),
)
}
}
}
impl Serialize for CapsFeatures {
fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
self.as_ref().serialize(serializer)
}
}
struct CapsFeaturesSome(CapsFeatures);
struct CapsFeaturesSomeVisitor;
impl<'de> Visitor<'de> for CapsFeaturesSomeVisitor {
type Value = CapsFeaturesSome;
fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
formatter.write_str("a sequence of `&str`")
}
fn visit_seq<A: SeqAccess<'de>>(self, mut seq: A) -> Result<Self::Value, A::Error> {
let mut features = CapsFeatures::new_empty();
while let Some(feature) = seq.next_element::<String>()? {
features.add(feature.as_ref());
}
Ok(CapsFeaturesSome(features))
}
}
impl<'de> Deserialize<'de> for CapsFeaturesSome {
fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<CapsFeaturesSome, D::Error> {
deserializer.deserialize_seq(CapsFeaturesSomeVisitor)
}
}
struct CapsFeaturesVariantKindsVisitor;
impl<'de> Visitor<'de> for CapsFeaturesVariantKindsVisitor {
type Value = CapsFeaturesVariantKinds;
fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
formatter.write_str("a Caps variant kind (`Any` or `Some`)")
}
fn visit_u32<E: de::Error>(self, value: u32) -> Result<Self::Value, E> {
match value {
CAPS_FEATURES_VARIANT_ANY_ID => Ok(CapsFeaturesVariantKinds::Any),
CAPS_FEATURES_VARIANT_SOME_ID => Ok(CapsFeaturesVariantKinds::Some),
_ => Err(de::Error::invalid_value(
de::Unexpected::Unsigned(u64::from(value)),
&self,
)),
}
}
fn visit_str<E: de::Error>(self, value: &str) -> Result<Self::Value, E> {
match value {
CAPS_FEATURES_VARIANT_ANY_STR => Ok(CapsFeaturesVariantKinds::Any),
CAPS_FEATURES_VARIANT_SOME_STR => Ok(CapsFeaturesVariantKinds::Some),
_ => Err(de::Error::unknown_variant(
value,
CAPS_FEATURES_VARIANT_NAMES,
)),
}
}
}
impl<'de> Deserialize<'de> for CapsFeaturesVariantKinds {
fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
deserializer.deserialize_identifier(CapsFeaturesVariantKindsVisitor)
}
}
struct CapsFeaturesVisitor;
impl<'de> Visitor<'de> for CapsFeaturesVisitor {
type Value = CapsFeatures;
fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
formatter.write_str("a CapsFeatures enum (`Any` or `Some()`)")
}
fn visit_enum<A: EnumAccess<'de>>(self, data: A) -> Result<Self::Value, A::Error> {
let res = match data.variant()? {
(CapsFeaturesVariantKinds::Any, _v) => CapsFeatures::new_any(),
(CapsFeaturesVariantKinds::Some, v) => v
.newtype_variant::<CapsFeaturesSome>()
.map(|caps_features_some| caps_features_some.0)?,
};
Ok(res)
}
}
impl<'de> Deserialize<'de> for CapsFeatures {
fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
deserializer.deserialize_enum(
stringify!(Caps),
CAPS_FEATURES_VARIANT_NAMES,
CapsFeaturesVisitor,
)
}
}