From 0d332faf48ec417d2e3d8d1fcc9c89e84a0fec4f Mon Sep 17 00:00:00 2001
From: Christian Duerr <chris.durr@phylum.io>
Date: Tue, 17 Dec 2024 22:04:29 +0100
Subject: [PATCH 1/2] Add `Purl::combined_name` method

This method adds the inverse of `Purl::builder_with_combined_name`,
allowing ecosystem-specific accurate printing of package names with
namespaces.
---
 purl/src/lib.rs | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/purl/src/lib.rs b/purl/src/lib.rs
index 1bb845c..4a90591 100644
--- a/purl/src/lib.rs
+++ b/purl/src/lib.rs
@@ -355,6 +355,23 @@ impl Purl {
 
         builder
     }
+
+    /// Combine the namespace and ecosystem in the ecosystem-specific format.
+    pub fn combined_name(&self) -> Cow<'_, str> {
+        match self.package_type {
+            PackageType::Cargo | PackageType::Gem | PackageType::NuGet | PackageType::PyPI => {
+                self.name().into()
+            },
+            PackageType::Golang | PackageType::Npm => match self.namespace() {
+                Some(namespace) => Cow::Owned(format!("{}/{}", namespace, self.name())),
+                None => self.name().into(),
+            },
+            PackageType::Maven => match self.namespace() {
+                Some(namespace) => Cow::Owned(format!("{}:{}", namespace, self.name())),
+                None => self.name().into(),
+            },
+        }
+    }
 }
 
 /// Check whether a package type string is valid according to the rules of the
@@ -598,11 +615,18 @@ mod tests {
             Purl::builder_with_combined_name(PackageType::Npm, "@angular/cli").build().unwrap();
         assert_eq!(purl.namespace(), Some("@angular"));
         assert_eq!(purl.name(), "cli");
+        assert_eq!(purl.combined_name(), "@angular/cli");
 
         let purl = Purl::builder_with_combined_name(PackageType::Maven, "org.maven.plugins:pom")
             .build()
             .unwrap();
         assert_eq!(purl.namespace(), Some("org.maven.plugins"));
         assert_eq!(purl.name(), "pom");
+        assert_eq!(purl.combined_name(), "org.maven.plugins:pom");
+
+        let purl = Purl::builder_with_combined_name(PackageType::Cargo, "libc").build().unwrap();
+        assert_eq!(purl.namespace(), None);
+        assert_eq!(purl.name(), "libc");
+        assert_eq!(purl.combined_name(), "libc");
     }
 }

From 170e9fb1c0178be432ea35c218273ffe1c60d6e4 Mon Sep 17 00:00:00 2001
From: Christian Duerr <chris.durr@phylum.io>
Date: Tue, 17 Dec 2024 22:16:31 +0100
Subject: [PATCH 2/2] Add serde support to `PackageType`

This adds both serialization and deserialization to the `PackageType`
enum, based on its lowercase representation.
---
 purl/Cargo.toml          | 2 +-
 purl/src/package_type.rs | 4 ++++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/purl/Cargo.toml b/purl/Cargo.toml
index e09a7d4..d42949b 100644
--- a/purl/Cargo.toml
+++ b/purl/Cargo.toml
@@ -18,7 +18,7 @@ package-type = ["phf", "unicase"]
 hex = "0.4.3"
 percent-encoding = "2.2.0"
 phf = { version = "0.11.1", features = ["macros", "unicase"], optional = true }
-serde = { version = "1.0.150", optional = true }
+serde = { version = "1.0.150", optional = true, features = ["derive"] }
 smartstring = { version = "1.0.1", optional = true }
 thiserror = "1.0.37"
 unicase = { version = "2.6.0", optional = true }
diff --git a/purl/src/package_type.rs b/purl/src/package_type.rs
index ecc2f35..ce2f1f3 100644
--- a/purl/src/package_type.rs
+++ b/purl/src/package_type.rs
@@ -5,6 +5,8 @@ use std::fmt;
 use std::str::FromStr;
 
 use phf::phf_map;
+#[cfg(feature = "serde")]
+use serde::{Deserialize, Serialize};
 use unicase::UniCase;
 
 use crate::{
@@ -134,6 +136,8 @@ pub type PurlBuilder = GenericPurlBuilder<PackageType>;
 ///
 /// This is a subset of the types described in the PURL spec repository. See
 /// [`Purl`] for details.
+#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
+#[cfg_attr(feature = "serde", serde(rename_all = "lowercase"))]
 #[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
 #[non_exhaustive]
 pub enum PackageType {