collect additional fields on TargetsMetadata

Signed-off-by: Luke Steensen <luke.steensen@gmail.com>

Author: lukesteensen

tuf/src/metadata.rs

@@ -1841,6 +1841,7 @@ pub struct TargetsMetadata {
     expires: DateTime<Utc>,
     targets: HashMap<TargetPath, TargetDescription>,
     delegations: Delegations,
+    additional_fields: HashMap<String, serde_json::Value>,
 }
 
 impl TargetsMetadata {
@@ -1850,6 +1851,7 @@ impl TargetsMetadata {
         expires: DateTime<Utc>,
         targets: HashMap<TargetPath, TargetDescription>,
         delegations: Delegations,
+        additional_fields: HashMap<String, serde_json::Value>,
     ) -> Result<Self> {
         if version < 1 {
             return Err(Error::MetadataVersionMustBeGreaterThanZero(
@@ -1862,6 +1864,7 @@ impl TargetsMetadata {
             expires,
             targets,
             delegations,
+            additional_fields,
         })
     }
 
@@ -1874,6 +1877,11 @@ impl TargetsMetadata {
     pub fn delegations(&self) -> &Delegations {
         &self.delegations
     }
+
+    /// An immutable reference to any additional fields on the metadata.
+    pub fn additional_fields(&self) -> &HashMap<String, serde_json::Value> {
+        &self.additional_fields
+    }
 }
 
 impl Metadata for TargetsMetadata {
@@ -1990,6 +1998,7 @@ impl TargetsMetadataBuilder {
             self.expires,
             self.targets,
             self.delegations.unwrap_or_default(),
+            Default::default(),
         )
     }
 
@@ -3259,6 +3268,7 @@ mod test {
             Utc.with_ymd_and_hms(2038, 1, 1, 0, 0, 0).unwrap(),
             hashmap!(),
             Delegations::default(),
+            Default::default(),
         )
         .unwrap();
 

tuf/src/pouf/pouf1/shims.rs

@@ -291,6 +291,8 @@ pub struct TargetsMetadata {
     targets: BTreeMap<metadata::TargetPath, metadata::TargetDescription>,
     #[serde(default, skip_serializing_if = "metadata::Delegations::is_empty")]
     delegations: metadata::Delegations,
+    #[serde(flatten)]
+    additional_fields: BTreeMap<String, serde_json::Value>,
 }
 
 impl TargetsMetadata {
@@ -306,6 +308,11 @@ impl TargetsMetadata {
                 .map(|(p, d)| (p.clone(), d.clone()))
                 .collect(),
             delegations: metadata.delegations().clone(),
+            additional_fields: metadata
+                .additional_fields()
+                .iter()
+                .map(|(p, d)| (p.clone(), d.clone()))
+                .collect(),
         })
     }
 
@@ -329,6 +336,7 @@ impl TargetsMetadata {
             parse_datetime(&self.expires)?,
             self.targets.into_iter().collect(),
             self.delegations,
+            self.additional_fields.into_iter().collect(),
         )
     }
 }