proper blockchain json parsing

json/src/uint.rs

@@ -0,0 +1,84 @@
+// Copyright 2015, 2016 Ethcore (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Lenient uint json deserialization for test json files.
+
+use std::str::FromStr;
+use serde::{Deserialize, Deserializer, Error};
+use serde::de::Visitor;
+use util::numbers::{U256, Uint as U};
+
+/// Lenient uint json deserialization for test json files.
+#[derive(Default, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct Uint(U256);
+
+impl Into<U256> for Uint {
+	fn into(self) -> U256 {
+		self.0
+	}
+}
+
+impl Deserialize for Uint {
+	fn deserialize<D>(deserializer: &mut D) -> Result<Self, D::Error>
+		where D: Deserializer {
+		deserializer.deserialize(UintVisitor)
+	}
+}
+
+struct UintVisitor;
+
+impl Visitor for UintVisitor {
+	type Value = Uint;
+
+	fn visit_str<E>(&mut self, value: &str) -> Result<Self::Value, E> where E: Error {
+		let value = match value.len() {
+			0 => U256::from(0),
+			2 if value.starts_with("0x") => U256::from(0),
+			_ if value.starts_with("0x") => try!(U256::from_str(&value[2..]).map_err(|_| Error::custom("invalid hex value."))),
+			_ => try!(U256::from_dec_str(value).map_err(|_| Error::custom("invalid decimal value.")))
+		};
+
+		Ok(Uint(value))
+	}
+
+	fn visit_string<E>(&mut self, value: String) -> Result<Self::Value, E> where E: Error {
+		self.visit_str(value.as_ref())
+	}
+}
+
+#[cfg(test)]
+mod test {
+	use serde_json;
+	use util::numbers::U256;
+	use uint::Uint;
+
+	#[test]
+	fn uint_deserialization() {
+		let s = r#"["0xa", "10", "", "0x"]"#;
+		let deserialized: Vec<Uint> = serde_json::from_str(s).unwrap();
+		assert_eq!(deserialized, vec![
+				   Uint(U256::from(10)),
+				   Uint(U256::from(10)),
+				   Uint(U256::from(0)),
+				   Uint(U256::from(0))
+		]);
+	}
+
+	#[test]
+	fn uint_into() {
+		assert_eq!(U256::from(10), Uint(U256::from(10)).into());
+	}
+}