add serialization for virtual packages

crates/rattler_conda_types/src/generic_virtual_package.rs

@@ -1,3 +1,5 @@
+use serde::{Deserialize, Serialize};
+
 use crate::{PackageName, Version};
 use std::fmt::{Display, Formatter};
 
@@ -17,12 +19,75 @@ pub struct GenericVirtualPackage {
 
 impl Display for GenericVirtualPackage {
     fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
-        write!(
-            f,
-            "{}={}={}",
-            &self.name.as_normalized(),
-            &self.version,
-            &self.build_string
-        )
+        write!(f, "{}={}", &self.name.as_normalized(), &self.version)?;
+        if self.build_string.is_empty() {
+            return Ok(());
+        }
+        write!(f, "={}", &self.build_string)
+    }
+}
+
+impl Serialize for GenericVirtualPackage {
+    fn serialize<S: serde::Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
+        let s = format!("{self}");
+        serializer.serialize_str(&s)
+    }
+}
+
+impl<'de> Deserialize<'de> for GenericVirtualPackage {
+    fn deserialize<D: serde::Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
+        let s = String::deserialize(deserializer)?;
+        let mut parts = s.split('=');
+
+        let name = parts
+            .next()
+            .ok_or_else(|| serde::de::Error::custom("No package name given"))?
+            .parse()
+            .map_err(serde::de::Error::custom)?;
+        let version = parts
+            .next()
+            .unwrap_or("0")
+            .parse()
+            .map_err(serde::de::Error::custom)?;
+        let build_string = parts.next().unwrap_or("").to_string();
+
+        Ok(GenericVirtualPackage {
+            name,
+            version,
+            build_string,
+        })
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use serde_json;
+
+    #[test]
+    fn test_serde() {
+        let p = GenericVirtualPackage {
+            name: "foo".parse().unwrap(),
+            version: "1.2.3".parse().unwrap(),
+            build_string: "py_0".to_string(),
+        };
+        let s = serde_json::to_string(&p).unwrap();
+        assert_eq!(s, "\"foo=1.2.3=py_0\"");
+        let p2: GenericVirtualPackage = serde_json::from_str(&s).unwrap();
+        assert_eq!(p, p2);
+
+        let p = GenericVirtualPackage {
+            name: "foo".parse().unwrap(),
+            version: "1.2.3".parse().unwrap(),
+            build_string: "".to_string(),
+        };
+        let s = serde_json::to_string(&p).unwrap();
+        assert_eq!(s, "\"foo=1.2.3\"");
+        let p2: GenericVirtualPackage = serde_json::from_str(&s).unwrap();
+        assert_eq!(p, p2);
+
+        let p2: GenericVirtualPackage = serde_json::from_str("\"__cuda\"").unwrap();
+        let s = serde_json::to_string(&p2).unwrap();
+        assert_eq!(s, "\"__cuda=0\"");
     }
 }