Add unused proposals to CommitOutput (#67)

* Add unused proposals to CommitOutput

* Fix ProposalInfo specialization

- The specialization macro needs to be invoked after the impl block, so
  that macros generated for this block are available at the
  specialization point.
- Macro qualification is not supported in the crate where the macro is
  defined.

---------

Co-authored-by: Stephane Raux <[email protected]>

mls-rs/src/group/commit.rs

@@ -94,6 +94,9 @@ pub struct CommitOutput {
     /// functionality. This value is set if [`MlsRules::commit_options`] returns
     /// `allow_external_commit` set to true.
     pub external_commit_group_info: Option<MlsMessage>,
+    /// Proposals that were received in the prior epoch but not included in the following commit.
+    #[cfg(feature = "by_ref_proposal")]
+    pub unused_proposals: Vec<crate::mls_rules::ProposalInfo<Proposal>>,
 }
 
 #[cfg_attr(all(feature = "ffi", not(test)), ::safer_ffi_gen::safer_ffi_gen)]
@@ -117,6 +120,20 @@ impl CommitOutput {
     pub fn ratchet_tree(&self) -> Option<&ExportedTree<'static>> {
         self.ratchet_tree.as_ref()
     }
+
+    /// A group info that can be provided to new members in order to enable external commit
+    /// functionality. This value is set if [`MlsRules::commit_options`] returns
+    /// `allow_external_commit` set to true.
+    #[cfg(feature = "ffi")]
+    pub fn external_commit_group_info(&self) -> Option<&MlsMessage> {
+        self.external_commit_group_info.as_ref()
+    }
+
+    /// Proposals that were received in the prior epoch but not included in the following commit.
+    #[cfg(all(feature = "ffi", feature = "by_ref_proposal"))]
+    pub fn unused_proposals(&self) -> &[crate::mls_rules::ProposalInfo<Proposal>] {
+        &self.unused_proposals
+    }
 }
 
 /// Build a commit with multiple proposals by-value.
@@ -722,6 +739,8 @@ where
             welcome_messages,
             ratchet_tree,
             external_commit_group_info,
+            #[cfg(feature = "by_ref_proposal")]
+            unused_proposals: provisional_state.rejected_proposals,
         })
     }
 

mls-rs/src/group/framing.rs

@@ -36,6 +36,10 @@ impl From<&Content> for ContentType {
     }
 }
 
+#[cfg_attr(
+    all(feature = "ffi", not(test)),
+    safer_ffi_gen::ffi_type(clone, opaque)
+)]
 #[derive(Clone, Copy, Debug, PartialEq, Eq, MlsSize, MlsEncode, MlsDecode)]
 #[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[repr(u8)]

mls-rs/src/group/message_processor.rs

@@ -35,10 +35,10 @@ use super::proposal_ref::ProposalRef;
 #[cfg(not(feature = "by_ref_proposal"))]
 use crate::group::proposal_cache::resolve_for_commit;
 
-#[cfg(any(feature = "state_update", feature = "by_ref_proposal"))]
+#[cfg(feature = "by_ref_proposal")]
 use super::proposal::Proposal;
 
-#[cfg(all(feature = "state_update", feature = "custom_proposal"))]
+#[cfg(feature = "custom_proposal")]
 use super::proposal_filter::ProposalInfo;
 
 #[cfg(feature = "state_update")]
@@ -72,7 +72,7 @@ pub(crate) struct ProvisionalState {
     pub(crate) group_context: GroupContext,
     pub(crate) external_init_index: Option<LeafIndex>,
     pub(crate) indexes_of_added_kpkgs: Vec<LeafIndex>,
-    #[cfg(all(feature = "state_update", feature = "by_ref_proposal"))]
+    #[cfg(feature = "by_ref_proposal")]
     pub(crate) rejected_proposals: Vec<crate::mls_rules::ProposalInfo<Proposal>>,
 }
 

mls-rs/src/group/proposal_cache.rs

@@ -194,7 +194,7 @@ impl GroupState {
         let roster = self.public_tree.roster();
         let group_extensions = &self.context.extensions;
 
-        #[cfg(all(feature = "by_ref_proposal", feature = "state_update"))]
+        #[cfg(feature = "by_ref_proposal")]
         let all_proposals = proposals.clone();
 
         let origin = match sender {
@@ -248,7 +248,7 @@ impl GroupState {
             .apply_proposals(&sender, &proposals, commit_time)
             .await?;
 
-        #[cfg(all(feature = "by_ref_proposal", feature = "state_update"))]
+        #[cfg(feature = "by_ref_proposal")]
         let rejected_proposals =
             rejected_proposals(all_proposals, &applier_output.applied_proposals);
 
@@ -268,7 +268,7 @@ impl GroupState {
             applied_proposals: proposals,
             external_init_index: applier_output.external_init_index,
             indexes_of_added_kpkgs: applier_output.indexes_of_added_kpkgs,
-            #[cfg(all(feature = "by_ref_proposal", feature = "state_update"))]
+            #[cfg(feature = "by_ref_proposal")]
             rejected_proposals,
         })
     }
@@ -284,14 +284,14 @@ impl Extend<(ProposalRef, CachedProposal)> for ProposalCache {
     }
 }
 
-#[cfg(all(feature = "by_ref_proposal", feature = "state_update"))]
+#[cfg(feature = "by_ref_proposal")]
 fn has_ref(proposals: &ProposalBundle, reference: &ProposalRef) -> bool {
     proposals
         .iter_proposals()
         .any(|p| matches!(&p.source, ProposalSource::ByReference(r) if r == reference))
 }
 
-#[cfg(all(feature = "by_ref_proposal", feature = "state_update"))]
+#[cfg(feature = "by_ref_proposal")]
 fn rejected_proposals(
     all_proposals: ProposalBundle,
     accepted_proposals: &ProposalBundle,

mls-rs/src/group/proposal_filter/bundle.rs

@@ -434,6 +434,10 @@ impl ProposalBundle {
     }
 }
 
+#[cfg_attr(
+    all(feature = "ffi", not(test)),
+    safer_ffi_gen::ffi_type(clone, opaque)
+)]
 #[derive(Clone, Debug, PartialEq)]
 pub enum ProposalSource {
     ByValue,
@@ -442,6 +446,7 @@ pub enum ProposalSource {
     Local,
 }
 
+#[cfg_attr(all(feature = "ffi", not(test)), safer_ffi_gen::ffi_type(opaque))]
 #[derive(Clone, Debug, PartialEq)]
 #[non_exhaustive]
 /// Proposal description used as input to a
@@ -455,7 +460,8 @@ pub struct ProposalInfo<T> {
     pub source: ProposalSource,
 }
 
-impl ProposalInfo<Proposal> {
+#[cfg_attr(all(feature = "ffi", not(test)), ::safer_ffi_gen::safer_ffi_gen)]
+impl<T> ProposalInfo<T> {
     /// Create a new ProposalInfo.
     ///
     /// The resulting value will be either transmitted with a commit or
@@ -464,7 +470,8 @@ impl ProposalInfo<Proposal> {
     ///
     /// This function is useful when implementing custom
     /// [`MlsRules`](crate::MlsRules).
-    pub fn new(proposal: Proposal, sender: Sender, can_transmit: bool) -> ProposalInfo<Proposal> {
+    #[cfg_attr(all(feature = "ffi", not(test)), safer_ffi_gen::safer_ffi_gen_ignore)]
+    pub fn new(proposal: T, sender: Sender, can_transmit: bool) -> Self {
         let source = if can_transmit {
             ProposalSource::ByValue
         } else {
@@ -477,9 +484,18 @@ impl ProposalInfo<Proposal> {
             source,
         }
     }
-}
 
-impl<T> ProposalInfo<T> {
+    #[cfg(all(feature = "ffi", not(test)))]
+    pub fn sender(&self) -> &Sender {
+        &self.sender
+    }
+
+    #[cfg(all(feature = "ffi", not(test)))]
+    pub fn source(&self) -> &ProposalSource {
+        &self.source
+    }
+
+    #[cfg_attr(all(feature = "ffi", not(test)), safer_ffi_gen::safer_ffi_gen_ignore)]
     pub fn map<U, F>(self, f: F) -> ProposalInfo<U>
     where
         F: FnOnce(T) -> U,
@@ -491,6 +507,7 @@ impl<T> ProposalInfo<T> {
         }
     }
 
+    #[cfg_attr(all(feature = "ffi", not(test)), safer_ffi_gen::safer_ffi_gen_ignore)]
     pub fn as_ref(&self) -> ProposalInfo<&T> {
         ProposalInfo {
             proposal: &self.proposal,
@@ -519,6 +536,9 @@ impl<T> ProposalInfo<T> {
     }
 }
 
+#[cfg(all(feature = "ffi", not(test)))]
+safer_ffi_gen::specialize!(ProposalInfoFfi = ProposalInfo<Proposal>);
+
 pub trait Proposable: Sized {
     const TYPE: ProposalType;
 

mls-rs/src/group/proposal_ref.rs

@@ -5,6 +5,10 @@
 use super::*;
 use crate::hash_reference::HashReference;
 
+#[cfg_attr(
+    all(feature = "ffi", not(test)),
+    safer_ffi_gen::ffi_type(clone, opaque)
+)]
 #[derive(Debug, Clone, PartialEq, Eq, Hash, PartialOrd, Ord, MlsSize, MlsEncode, MlsDecode)]
 #[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 /// Unique identifier for a proposal message.
@@ -18,6 +22,7 @@ impl Deref for ProposalRef {
     }
 }
 
+#[cfg_attr(all(feature = "ffi", not(test)), ::safer_ffi_gen::safer_ffi_gen)]
 impl ProposalRef {
     #[cfg_attr(not(mls_build_async), maybe_async::must_be_sync)]
     pub(crate) async fn from_content<CS: CipherSuiteProvider>(
@@ -31,6 +36,10 @@ impl ProposalRef {
                 .await?,
         ))
     }
+
+    pub fn as_slice(&self) -> &[u8] {
+        &self.0
+    }
 }
 
 #[cfg(test)]