82 lines
2.4 KiB
Rust
82 lines
2.4 KiB
Rust
// Copyright 2015, 2016 Ethcore (UK) Ltd.
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// This file is part of Parity.
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// Parity is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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// Parity is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License
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// along with Parity. If not, see <http://www.gnu.org/licenses/>.
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use serde::{Serialize, Serializer, Deserialize, Deserializer};
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use serde_json::Value;
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/// Optional value
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#[derive(Debug)]
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pub enum OptionalValue<T> where T: Serialize {
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/// Some
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Value(T),
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/// None
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Null
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}
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impl<T> Default for OptionalValue<T> where T: Serialize + Deserialize {
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fn default() -> Self {
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OptionalValue::Null
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}
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}
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impl<T> Into<Option<T>> for OptionalValue<T> where T: Serialize + Deserialize {
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fn into(self) -> Option<T> {
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match self {
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OptionalValue::Null => None,
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OptionalValue::Value(t) => Some(t),
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}
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}
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}
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impl<T> Serialize for OptionalValue<T> where T: Serialize + Deserialize {
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fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
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where S: Serializer {
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match *self {
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OptionalValue::Value(ref value) => value.serialize(serializer),
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OptionalValue::Null => Value::Null.serialize(serializer)
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}
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}
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}
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impl<T> Deserialize for OptionalValue<T> where T: Serialize + Deserialize {
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fn deserialize<D>(deserializer: &mut D) -> Result<OptionalValue<T>, D::Error>
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where D: Deserializer {
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let deser_result: Result<T, D::Error> = Deserialize::deserialize(deserializer);
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match deser_result {
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Ok(t) => Ok(OptionalValue::Value(t)),
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Err(_) => Ok(OptionalValue::Null),
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}
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}
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}
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#[cfg(test)]
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mod tests {
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use serde_json;
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use util::hash::*;
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use super::*;
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#[test]
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fn test_serialize_optional_value() {
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let v: OptionalValue<H256> = OptionalValue::Null;
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let serialized = serde_json::to_string(&v).unwrap();
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assert_eq!(serialized, r#"null"#);
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let v = OptionalValue::Value(H256::default());
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let serialized = serde_json::to_string(&v).unwrap();
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assert_eq!(serialized, r#""0x0000000000000000000000000000000000000000000000000000000000000000""#);
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}
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}
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