pkcs7: add ValueOrd impls

Followup from #813

Author: tarcieri

pkcs7/src/cms_version.rs

@@ -1,6 +1,7 @@
 //! `CMSVersion` [RFC 5652 § 10.2.5](https://datatracker.ietf.org/doc/html/rfc5652#section-10.2.5)
 
-use der::Enumerated;
+use core::cmp::Ordering;
+use der::{Enumerated, ValueOrd};
 
 /// The CMSVersion type gives a syntax version number, for compatibility
 /// with future revisions of this specification.
@@ -10,7 +11,7 @@ use der::Enumerated;
 /// ```
 ///
 /// See [RFC 5652 10.2.5](https://datatracker.ietf.org/doc/html/rfc5652#section-10.2.5).
-#[derive(Clone, Copy, Debug, Enumerated, Eq, PartialEq)]
+#[derive(Clone, Copy, Debug, Enumerated, Eq, PartialEq, PartialOrd, Ord)]
 #[asn1(type = "INTEGER")]
 #[repr(u8)]
 pub enum CmsVersion {
@@ -27,3 +28,16 @@ pub enum CmsVersion {
     /// syntax version 5
     V5 = 5,
 }
+
+impl From<CmsVersion> for u8 {
+    fn from(version: CmsVersion) -> u8 {
+        version as u8
+    }
+}
+
+// TODO(tarcieri): fix `ValueOrd` derive for this case (`asn1` attribute is clashing)
+impl ValueOrd for CmsVersion {
+    fn value_cmp(&self, other: &Self) -> der::Result<Ordering> {
+        Ok(self.cmp(other))
+    }
+}

pkcs7/src/signer_info.rs

@@ -1,7 +1,5 @@
 //! `SignerInfo` data type [RFC 5652 § 5.3](https://datatracker.ietf.org/doc/html/rfc5652#section-5.3)
 
-use core::cmp::Ordering;
-
 use crate::cms_version::CmsVersion;
 use der::{
     asn1::{OctetStringRef, SetOfVec},
@@ -37,7 +35,7 @@ type UnsignedAttributes<'a> = SetOfVec<Attribute>;
 //    issuerAndSerialNumber IssuerAndSerialNumber,
 //    subjectKeyIdentifier [0] SubjectKeyIdentifier }
 /// ```
-#[derive(Clone, Debug, PartialEq, Eq, Choice)]
+#[derive(Clone, Debug, PartialEq, Eq, Choice, ValueOrd)]
 pub enum SignerIdentifier<'a> {
     /// issuer and serial number
     IssuerAndSerialNumber(IssuerAndSerialNumber),
@@ -47,7 +45,7 @@ pub enum SignerIdentifier<'a> {
     SubjectKeyIdentifier(SubjectKeyIdentifier<'a>),
 }
 
-#[derive(Clone, Debug, Eq, PartialEq, Sequence)]
+#[derive(Clone, Debug, Eq, PartialEq, Sequence, ValueOrd)]
 #[allow(missing_docs)]
 pub struct IssuerAndSerialNumber {
     pub name: Name,
@@ -71,7 +69,7 @@ pub type SignerInfos<'a> = SetOfVec<SignerInfo<'a>>;
 ///     signature SignatureValue,
 ///     unsignedAttrs [1] IMPLICIT UnsignedAttributes OPTIONAL }
 /// ```
-#[derive(Clone, Debug, Eq, PartialEq, Sequence)]
+#[derive(Clone, Debug, Eq, PartialEq, Sequence, ValueOrd)]
 pub struct SignerInfo<'a> {
     /// the syntax version number.
     pub version: CmsVersion,
@@ -96,10 +94,3 @@ pub struct SignerInfo<'a> {
     #[asn1(context_specific = "1", tag_mode = "IMPLICIT", optional = "true")]
     pub unsigned_attributes: Option<UnsignedAttributes<'a>>,
 }
-
-// TODO: figure out what ordering makes sense - if any
-impl ValueOrd for SignerInfo<'_> {
-    fn value_cmp(&self, _other: &Self) -> der::Result<Ordering> {
-        Ok(Ordering::Equal)
-    }
-}