gstreamer-rs/gstreamer/src/caps_serde.rs

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// Copyright (C) 2018 François Laignel <fengalin@free.fr>
//
// 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, SeqAccess, Visitor};
use serde::ser::{Serialize, SerializeSeq, SerializeTuple, Serializer};
use std::fmt;
use Caps;
use CapsRef;
use Structure;
use StructureRef;
// `CapsFeature` is not available in `gstreamer-rs` yet
struct CapsItemSe<'a>(&'a StructureRef);
impl<'a> Serialize for CapsItemSe<'a> {
fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
let mut tup = serializer.serialize_tuple(2)?;
tup.serialize_element(self.0)?;
// `CapsFeature` is not available in `gstreamer-rs` yet
// Fake the type for now and use `None` as a value
tup.serialize_element::<Option<Structure>>(&None)?;
tup.end()
}
}
impl Serialize for CapsRef {
fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
let iter = self.iter();
let size = iter.size_hint().0;
if size > 0 {
let mut seq = serializer.serialize_seq(Some(size))?;
for structure in iter {
seq.serialize_element(&CapsItemSe(structure))?;
}
seq.end()
} else {
let seq = serializer.serialize_seq(None)?;
seq.end()
}
}
}
impl Serialize for Caps {
fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
self.as_ref().serialize(serializer)
}
}
// `CapsFeature` is not available in `gstreamer-rs` yet
struct CapsItemDe(Structure);
impl From<CapsItemDe> for Structure {
fn from(caps_item: CapsItemDe) -> Structure {
caps_item.0
}
}
struct CapsItemVisitor;
impl<'de> Visitor<'de> for CapsItemVisitor {
type Value = CapsItemDe;
fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
formatter.write_str("a tuple `(Structure, Option<CapsFeature>)`")
}
fn visit_seq<A: SeqAccess<'de>>(self, mut seq: A) -> Result<Self::Value, A::Error> {
let structure = seq
.next_element::<Structure>()?
.ok_or(de::Error::custom("Expected a `Structure` for `Caps` item"))?;
// `CapsFeature` is not available in `gstreamer-rs` yet
// Fake the type for now and expect `None` as a value
let feature_option = seq
.next_element::<Option<Structure>>()?
.ok_or(de::Error::custom(
"Expected an `Option<CapsFeature>` for `Caps` item",
))?;
if feature_option.is_some() {
Err(de::Error::custom(
"Found a value for `CapsFeature`, expected `None` (not implemented yet)",
))
} else {
Ok(CapsItemDe(structure))
}
}
}
impl<'de> Deserialize<'de> for CapsItemDe {
fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<CapsItemDe, D::Error> {
deserializer.deserialize_tuple(2, CapsItemVisitor)
}
}
struct CapsVisitor;
impl<'de> Visitor<'de> for CapsVisitor {
type Value = Caps;
fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
formatter.write_str("a sequence of `(Structure, Option<CapsFeature>)`")
}
fn visit_seq<A: SeqAccess<'de>>(self, mut seq: A) -> Result<Self::Value, A::Error> {
let mut caps = Caps::new_empty();
{
let caps = caps.get_mut().unwrap();
while let Some(caps_item) = seq.next_element::<CapsItemDe>()? {
caps.append_structure(caps_item.into());
}
}
Ok(caps)
}
}
impl<'de> Deserialize<'de> for Caps {
fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
deserializer.deserialize_seq(CapsVisitor)
}
}
#[cfg(test)]
mod tests {
extern crate ron;
use Array;
use Caps;
use Fraction;
#[test]
fn test_serialize() {
::init().unwrap();
let caps = Caps::builder("foo/bar")
.field("int", &12)
.field("bool", &true)
.field("string", &"bla")
.field("fraction", &Fraction::new(1, 2))
.field("array", &Array::new(&[&1, &2]))
.build();
let mut pretty_config = ron::ser::PrettyConfig::default();
pretty_config.new_line = "".to_string();
let res = ron::ser::to_string_pretty(&caps, pretty_config);
assert_eq!(
Ok(concat!(
"[",
" ((\"foo/bar\", [",
" (\"int\", \"i32\", 12),",
" (\"bool\", \"bool\", true),",
" (\"string\", \"String\", \"bla\"),",
" (\"fraction\", \"Fraction\", (1, 2)),",
" (\"array\", \"Array\", [",
" (\"i32\", 1),",
" (\"i32\", 2),",
" ]),",
" ]), None),",
"]"
).to_owned()),
res,
);
}
#[test]
fn test_deserialize() {
use Structure;
::init().unwrap();
let caps_ron = r#"
[
(
("foo/bar", [
("int", "i32", 12),
("bool", "bool", true),
("string", "String", "bla"),
("fraction", "Fraction", (1, 2)),
("array", "Array", [
("i32", 1),
("i32", 2),
]),
]),
None,
),
]"#;
let caps: Caps = ron::de::from_str(caps_ron).unwrap();
let s = caps.get_structure(0).unwrap();
assert_eq!(
s,
Structure::new(
"foo/bar",
&[
("int", &12),
("bool", &true),
("string", &"bla"),
("fraction", &Fraction::new(1, 2)),
("array", &Array::new(&[&1, &2])),
],
).as_ref()
);
}
}