fix(core): add derives, impls for Units (#1683)

* fix(core): add derives, impls for Units

* feat: add some more unit aliases

* remove separators

* feat: add more impl

* chore: run clippy

ethers-core/src/utils/units.rs

@@ -1,63 +1,141 @@
 use super::ConversionError;
+use std::{convert::TryFrom, fmt, str::FromStr};
 
 /// Common Ethereum unit types.
+#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord)]
 pub enum Units {
-    /// Ether corresponds to 1e18 Wei
-    Ether,
-    /// Gwei corresponds to 1e9 Wei
-    Gwei,
-    /// Wei corresponds to 1 Wei
+    /// Wei is equivalent to 1 wei.
     Wei,
-    /// Use this for other less frequent unit sizes
+    /// Gwei is equivalent to 1e9 wei.
+    Gwei,
+    /// Ether is equivalent to 1e18 wei.
+    Ether,
+    /// Other less frequent unit sizes, equivalent to 1e{0} wei.
     Other(u32),
 }
 
-impl Units {
-    pub fn as_num(&self) -> u32 {
-        match self {
-            Units::Ether => 18,
-            Units::Gwei => 9,
-            Units::Wei => 0,
-            Units::Other(inner) => *inner,
-        }
+impl fmt::Display for Units {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.pad(self.as_num().to_string().as_str())
     }
 }
 
-use std::convert::TryFrom;
-
 impl TryFrom<u32> for Units {
     type Error = ConversionError;
 
-    fn try_from(src: u32) -> Result<Self, Self::Error> {
-        Ok(Units::Other(src))
+    fn try_from(value: u32) -> Result<Self, Self::Error> {
+        Ok(Units::Other(value))
     }
 }
 
 impl TryFrom<i32> for Units {
     type Error = ConversionError;
 
-    fn try_from(src: i32) -> Result<Self, Self::Error> {
-        Ok(Units::Other(src as u32))
+    fn try_from(value: i32) -> Result<Self, Self::Error> {
+        Ok(Units::Other(value as u32))
     }
 }
 
 impl TryFrom<usize> for Units {
     type Error = ConversionError;
 
-    fn try_from(src: usize) -> Result<Self, Self::Error> {
-        Ok(Units::Other(src as u32))
+    fn try_from(value: usize) -> Result<Self, Self::Error> {
+        Ok(Units::Other(value as u32))
     }
 }
 
-impl std::convert::TryFrom<&str> for Units {
+impl TryFrom<String> for Units {
     type Error = ConversionError;
 
-    fn try_from(src: &str) -> Result<Self, Self::Error> {
-        Ok(match src.to_lowercase().as_str() {
-            "ether" => Units::Ether,
-            "gwei" => Units::Gwei,
+    fn try_from(value: String) -> Result<Self, Self::Error> {
+        Self::from_str(&value)
+    }
+}
+
+impl<'a> TryFrom<&'a String> for Units {
+    type Error = ConversionError;
+
+    fn try_from(value: &'a String) -> Result<Self, Self::Error> {
+        Self::from_str(value)
+    }
+}
+
+impl TryFrom<&str> for Units {
+    type Error = ConversionError;
+
+    fn try_from(value: &str) -> Result<Self, Self::Error> {
+        Self::from_str(value)
+    }
+}
+
+impl FromStr for Units {
+    type Err = ConversionError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        Ok(match s.to_lowercase().as_str() {
+            "eth" | "ether" => Units::Ether,
+            "gwei" | "nano" | "nanoether" => Units::Gwei,
             "wei" => Units::Wei,
-            _ => return Err(ConversionError::UnrecognizedUnits(src.to_string())),
+            _ => return Err(ConversionError::UnrecognizedUnits(s.to_string())),
         })
     }
 }
+
+impl From<Units> for u32 {
+    fn from(units: Units) -> Self {
+        units.as_num()
+    }
+}
+
+impl From<Units> for i32 {
+    fn from(units: Units) -> Self {
+        units.as_num() as i32
+    }
+}
+
+impl From<Units> for usize {
+    fn from(units: Units) -> Self {
+        units.as_num() as usize
+    }
+}
+
+impl Units {
+    pub fn as_num(&self) -> u32 {
+        match self {
+            Units::Wei => 0,
+            Units::Gwei => 9,
+            Units::Ether => 18,
+            Units::Other(inner) => *inner,
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use Units::*;
+
+    #[test]
+    fn test_units() {
+        assert_eq!(Wei.as_num(), 0);
+        assert_eq!(Gwei.as_num(), 9);
+        assert_eq!(Ether.as_num(), 18);
+        assert_eq!(Other(10).as_num(), 10);
+        assert_eq!(Other(20).as_num(), 20);
+    }
+
+    #[test]
+    fn test_into() {
+        assert_eq!(Units::try_from("wei").unwrap(), Wei);
+        assert_eq!(Units::try_from("gwei").unwrap(), Gwei);
+        assert_eq!(Units::try_from("ether").unwrap(), Ether);
+
+        assert_eq!(Units::try_from("wei".to_string()).unwrap(), Wei);
+        assert_eq!(Units::try_from("gwei".to_string()).unwrap(), Gwei);
+        assert_eq!(Units::try_from("ether".to_string()).unwrap(), Ether);
+
+        assert_eq!(Units::try_from(&"wei".to_string()).unwrap(), Wei);
+        assert_eq!(Units::try_from(&"gwei".to_string()).unwrap(), Gwei);
+        assert_eq!(Units::try_from(&"ether".to_string()).unwrap(), Ether);
+    }
+}