Add functionality to parse hashedrekord LogEntry

- Make signature fields public
- Add Body struct and implementation
- add base64 decoding

Signed-off-by: Lily Sturmann <lsturman@redhat.com>

src/rekor/models/hashedrekord.rs

@@ -8,8 +8,11 @@
  * Generated by: https://openapi-generator.tech
  */
 
+use base64::decode;
 use serde::{Deserialize, Serialize};
 
+use crate::errors::SigstoreError;
+
 /// Hashedrekord : Hashed Rekord object
 
 #[derive(Clone, Debug, Eq, PartialEq, Serialize, Deserialize)]
@@ -37,8 +40,8 @@ impl Hashedrekord {
 #[derive(Debug, Clone, Eq, PartialEq, Serialize, Deserialize)]
 #[serde(rename_all = "camelCase")]
 pub struct Spec {
-    signature: Signature,
-    data: Data,
+    pub signature: Signature,
+    pub data: Data,
 }
 
 // Design a SPEC struct
@@ -76,6 +79,11 @@ impl PublicKey {
     pub fn new(content: String) -> PublicKey {
         PublicKey { content }
     }
+
+    pub fn decode(&self) -> Result<String, SigstoreError> {
+        let decoded = decode(&self.content)?;
+        String::from_utf8(decoded).map_err(|e| SigstoreError::from(e.utf8_error()))
+    }
 }
 
 #[derive(Debug, Clone, Eq, PartialEq, Serialize, Deserialize)]

src/rekor/models/log_entry.rs

@@ -1,6 +1,10 @@
-use crate::rekor::TreeSize;
+use base64::decode;
 use serde::{Deserialize, Serialize};
 
+use crate::errors::SigstoreError;
+use crate::rekor::models::hashedrekord::Spec;
+use crate::rekor::TreeSize;
+
 /// Stores the response returned by Rekor after making a new entry
 #[derive(Default, Debug, Clone, Eq, PartialEq, Serialize, Deserialize)]
 #[serde(rename_all = "camelCase")]
@@ -15,6 +19,23 @@ pub struct LogEntry {
     pub verification: Verification,
 }
 
+impl LogEntry {
+    pub fn decode_body(&self) -> Result<Body, SigstoreError> {
+        let decoded = decode(&self.body)?;
+        serde_json::from_slice(&decoded).map_err(SigstoreError::from)
+    }
+}
+
+#[derive(Clone, Debug, PartialEq, Eq, Serialize, Deserialize)]
+pub struct Body {
+    #[serde(rename = "kind")]
+    pub kind: String,
+    #[serde(rename = "apiVersion")]
+    pub api_version: String,
+    #[serde(rename = "spec")]
+    pub spec: Spec,
+}
+
 #[derive(Default, Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
 #[serde(rename_all = "camelCase")]
 pub struct Attestation {