Structure: serde impl

gstreamer/src/structure.rs

@@ -655,6 +655,171 @@ impl Builder {
     }
 }
 
+#[cfg(feature = "ser_de")]
+pub(crate) mod serde {
+    use glib;
+    use glib::ToValue;
+
+    use serde::de;
+    use serde::de::{Deserialize, Deserializer, SeqAccess, Visitor};
+    use serde::ser;
+    use serde::ser::{Serialize, Serializer, SerializeSeq, SerializeTuple};
+
+    use std::fmt;
+
+    use DateTime;
+    //use Sample;
+
+    use value::*;
+    use value::serde::*;
+
+    use Structure;
+    use StructureRef;
+
+    struct FieldSe<'a>(&'a str, &'a glib::SendValue);
+    impl<'a> Serialize for FieldSe<'a> {
+        fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
+            ser_value!(self.1, |type_, value| {
+                let mut tup = serializer.serialize_tuple(3)?;
+                tup.serialize_element(self.0)?;
+                tup.serialize_element(type_)?;
+                tup.serialize_element(&value)?;
+                tup.end()
+            })
+        }
+    }
+
+    struct StructureForIter<'a>(&'a StructureRef);
+    impl<'a> Serialize for StructureForIter<'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 field in iter {
+                    seq.serialize_element(&FieldSe(field.0, field.1))?;
+                }
+                seq.end()
+            } else {
+                let seq = serializer.serialize_seq(None)?;
+                seq.end()
+            }
+        }
+    }
+
+    impl Serialize for StructureRef {
+        fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
+            let mut tup = serializer.serialize_tuple(2)?;
+            tup.serialize_element(self.get_name())?;
+            tup.serialize_element(&StructureForIter(self))?;
+            tup.end()
+        }
+    }
+
+    impl Serialize for Structure {
+        fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
+            self.as_ref().serialize(serializer)
+        }
+    }
+
+    struct FieldDe(String, SendValue);
+    impl From<FieldDe> for (String, glib::SendValue) {
+        fn from(field_de: FieldDe) -> Self {
+            (field_de.0, field_de.1.into())
+        }
+    }
+
+    struct FieldVisitor;
+    impl<'de> Visitor<'de> for FieldVisitor {
+        type Value = FieldDe;
+
+        fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+            formatter.write_str(
+                "a tuple of 3 elements (name: `String`, type name: `String`, value: `Value`)"
+            )
+        }
+
+        fn visit_seq<A: SeqAccess<'de>>(self, mut seq: A) -> Result<Self::Value, A::Error> {
+            let name = seq.next_element::<String>()?
+                .ok_or(de::Error::custom("Expected a value for `Value` name, found `None`"))?;
+            let type_name = seq.next_element::<String>()?
+                .ok_or(de::Error::custom("Expected a value for `Value` type, found `None`"))?;
+            Ok(FieldDe(name, de_send_value!(type_name, seq)))
+        }
+    }
+
+    impl<'de> Deserialize<'de> for FieldDe {
+        fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
+            deserializer.deserialize_tuple(3, FieldVisitor)
+        }
+    }
+
+    // Use `NamelessStructure` to deserialize the `Field`s and
+    // to add them to the `Structure` at the same time.
+    struct NamelessStructure(Structure);
+    impl From<NamelessStructure> for Structure {
+        fn from(nameless_structure: NamelessStructure) -> Self {
+            nameless_structure.0
+        }
+    }
+
+    struct NamelessStructureVisitor;
+    impl<'de> Visitor<'de> for NamelessStructureVisitor {
+        type Value = NamelessStructure;
+
+        fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+            formatter.write_str("a nameless `Structure` consisting of a sequence of `Field`s)")
+        }
+
+        fn visit_seq<A: SeqAccess<'de>>(self, mut seq: A) -> Result<Self::Value, A::Error> {
+            // Can't build a `Structure` with an empty name
+            let mut structure = Structure::new_empty("None");
+            while let Some(field) = seq.next_element::<FieldDe>()? {
+                let (name, value): (String, glib::SendValue) = field.into();
+                structure.as_mut().set_value(name.as_str(), value);
+            }
+
+            Ok(NamelessStructure(structure))
+        }
+    }
+
+    impl<'de> Deserialize<'de> for NamelessStructure {
+        fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
+            deserializer.deserialize_seq(NamelessStructureVisitor)
+        }
+    }
+
+    struct StructureVisitor;
+    impl<'de> Visitor<'de> for StructureVisitor {
+        type Value = Structure;
+
+        fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+            formatter.write_str("a `Structure`: (name: `String`, fields: sequence of `Field`s)")
+        }
+
+        fn visit_seq<A: SeqAccess<'de>>(self, mut seq: A) -> Result<Self::Value, A::Error> {
+            let name = seq.next_element::<String>()?
+                .ok_or(de::Error::custom(
+                    "Expected a name for the `Structure`, found `None`"
+                ))?;
+            let mut structure: Structure = seq.next_element::<NamelessStructure>()?
+                .ok_or(de::Error::custom(
+                    "Expected a sequence of `Field`s, found `None`"
+                ))?
+                .into();
+            structure.set_name(name.as_str());
+
+            Ok(structure)
+        }
+    }
+
+    impl<'de> Deserialize<'de> for Structure {
+        fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
+            deserializer.deserialize_tuple(2, StructureVisitor)
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -715,4 +880,82 @@ mod tests {
 
         assert_eq!(a, s.to_string());
     }
+
+    #[cfg(feature = "ser_de")]
+    #[test]
+    fn test_serialize() {
+        extern crate ron;
+
+        use Array;
+
+        ::init().unwrap();
+
+        let s = Structure::builder("test")
+            .field("f1", &"abc")
+            .field("f2", &String::from("bcd"))
+            .field("f3", &123i32)
+            .field("fraction", &Fraction::new(1, 2))
+            .field("array", &Array::new(&[&1, &2]))
+            .build();
+
+        // don't use newlines
+        let mut pretty_config = ron::ser::PrettyConfig::default();
+        pretty_config.new_line = "".to_string();
+
+        let res = ron::ser::to_string_pretty(&s, pretty_config);
+        assert_eq!(
+            Ok(
+                concat!(
+                    "(\"test\", [",
+                    "    (\"f1\", \"String\", \"abc\"),",
+                    "    (\"f2\", \"String\", \"bcd\"),",
+                    "    (\"f3\", \"i32\", 123),",
+                    "    (\"fraction\", \"Fraction\", (1, 2)),",
+                    "    (\"array\", \"Array\", [",
+                    "        (\"i32\", 1),",
+                    "        (\"i32\", 2),",
+                    "    ]),",
+                    "])"
+                )
+                    .to_owned()
+            ),
+            res,
+        );
+    }
+
+    #[cfg(feature = "ser_de")]
+    #[test]
+    fn test_deserialize() {
+        extern crate ron;
+
+        use Array;
+
+        ::init().unwrap();
+
+        let s_ron = r#"
+            ("test", [
+                ("f1", "String", "abc"),
+                ("f2", "String", "bcd"),
+                ("f3", "i32", 123),
+                ("fraction", "Fraction", (1, 2)),
+                ("array", "Array", [
+                    ("i32", 1),
+                    ("i32", 2),
+                ]),
+            ])"#;
+        let s: Structure = ron::de::from_str(s_ron).unwrap();
+        assert_eq!(
+            s.as_ref(),
+            Structure::new(
+                "test",
+                &[
+                    ("f1", &"abc"),
+                    ("f2", &"bcd"),
+                    ("f3", &123),
+                    ("fraction", &Fraction::new(1, 2)),
+                    ("array", &Array::new(&[&1, &2])),
+                ],
+            ).as_ref()
+        );
+    }
 }