bjoernager/rust
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extra::json: use a different encoding for enums.

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It now uses `{"type": VariantName, "fields": [...]}`, which, according to
@Seldaek, since all enums will have the same "shape" rather than being a weird
ad-hoc array, will optimize better in javascript JITs. It also looks prettier,
and makes more sense.
This commit is contained in:
Corey Richardson 2013-08-09 20:05:24 -04:00
parent 507a7f093d
commit 9ea295b7df
1 changed files with 24 additions and 15 deletions
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39
src/libextra/json.rs
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@ -135,18 +135,21 @@ impl serialize::Encoder for Encoder {
_id: uint, _id: uint,
cnt: uint, cnt: uint,
f: &fn(&mut Encoder)) { f: &fn(&mut Encoder)) {
// enums are encoded as strings or vectors: // enums are encoded as strings or objects
// Bunny => "Bunny" // Bunny => "Bunny"
// Kangaroo(34,"William") => ["Kangaroo",[34,"William"]] // Kangaroo(34,"William") => {"variant": "Kangaroo", "fields": [34,"William"]}
if cnt == 0 { if cnt == 0 {
self.wr.write_str(escape_str(name)); self.wr.write_str(escape_str(name));
} else { } else {
self.wr.write_char('['); self.wr.write_char('{');
self.wr.write_str("\"variant\"");
self.wr.write_char(':');
self.wr.write_str(escape_str(name)); self.wr.write_str(escape_str(name));
self.wr.write_char(','); self.wr.write_char(',');
self.wr.write_str("\"fields\"");
self.wr.write_str(":[");
f(self); f(self);
self.wr.write_char(']'); self.wr.write_str("]}");
} }
} }
@ -947,14 +950,20 @@ impl serialize::Decoder for Decoder {
debug!("read_enum_variant(names=%?)", names); debug!("read_enum_variant(names=%?)", names);
let name = match self.stack.pop() { let name = match self.stack.pop() {
String(s) => s, String(s) => s,
List(list) => { Object(o) => {
for v in list.move_rev_iter() { let n = match o.find(&~"variant").expect("invalidly encoded json") {
self.stack.push(v); &String(ref s) => s.clone(),
} _ => fail!("invalidly encoded json"),
match self.stack.pop() { };
String(s) => s, match o.find(&~"fields").expect("invalidly encoded json") {
value => fail!("invalid variant name: %?", value), &List(ref l) => {
for field in l.rev_iter() {
self.stack.push(field.clone());
}
},
_ => fail!("invalidly encoded json")
} }
n
} }
ref json => fail!("invalid variant: %?", *json), ref json => fail!("invalid variant: %?", *json),
}; };
@ -1517,7 +1526,7 @@ mod tests {
let mut encoder = Encoder(wr); let mut encoder = Encoder(wr);
animal.encode(&mut encoder); animal.encode(&mut encoder);
}, },
~"[\"Frog\",\"Henry\",349]" ~"{\"variant\":\"Frog\",\"fields\":[\"Henry\",349]}"
); );
assert_eq!( assert_eq!(
do io::with_str_writer |wr| { do io::with_str_writer |wr| {
@ -1921,14 +1930,14 @@ mod tests {
assert_eq!(value, Dog); assert_eq!(value, Dog);
let mut decoder = let mut decoder =
Decoder(from_str("[\"Frog\",\"Henry\",349]").unwrap()); Decoder(from_str("{\"variant\":\"Frog\",\"fields\":[\"Henry\",349]}").unwrap());
let value: Animal = Decodable::decode(&mut decoder); let value: Animal = Decodable::decode(&mut decoder);
assert_eq!(value, Frog(~"Henry", 349)); assert_eq!(value, Frog(~"Henry", 349));
} }
#[test] #[test]
fn test_decode_map() { fn test_decode_map() {
let s = ~"{\"a\": \"Dog\", \"b\": [\"Frog\", \"Henry\", 349]}"; let s = ~"{\"a\": \"Dog\", \"b\": {\"variant\":\"Frog\",\"fields\":[\"Henry\", 349]}}";
let mut decoder = Decoder(from_str(s).unwrap()); let mut decoder = Decoder(from_str(s).unwrap());
let mut map: TreeMap<~str, Animal> = Decodable::decode(&mut decoder); let mut map: TreeMap<~str, Animal> = Decodable::decode(&mut decoder);