[uniffi] Fix compilation under mls_build_async

UniFFI added support for async traits in mozilla/uniffi-rs#1981, but
this is not yet released. This commit temporarily introduces a Git
dependency on UniFFI to let us test the async functionality which was
removed in awslabs#86.

An unrelated UniFFI change (mozilla/uniffi-rs#1840) made our existing
test fail.

Author: mgeisler

mls-rs-uniffi/Cargo.toml

@@ -21,10 +21,10 @@ mls-rs = { version = "0.39.0", path = "../mls-rs" }
 mls-rs-core = { version = "0.18.0", path = "../mls-rs-core" }
 mls-rs-crypto-openssl = { version = "0.9.0", path = "../mls-rs-crypto-openssl" }
 thiserror = "1.0.57"
-uniffi = "0.26.0"
+uniffi = { git = "https://github.com/mozilla/uniffi-rs/", rev = "6b09f11", version = "0.26.0" }
 
 [target.'cfg(mls_build_async)'.dependencies]
 tokio = { version = "1.36.0", features = ["sync"] }
 
 [dev-dependencies]
-uniffi_bindgen = "0.26.0"
+uniffi_bindgen = { git = "https://github.com/mozilla/uniffi-rs/", rev = "6b09f11", version = "0.26.0" }

mls-rs-uniffi/src/config.rs

@@ -28,11 +28,11 @@ impl mls_rs_core::group::GroupStateStorage for ClientGroupStorage {
     type Error = Error;
 
     async fn state(&self, group_id: &[u8]) -> Result<Option<Vec<u8>>, Self::Error> {
-        self.0.state(group_id.to_vec())
+        self.0.state(group_id.to_vec()).await
     }
 
     async fn epoch(&self, group_id: &[u8], epoch_id: u64) -> Result<Option<Vec<u8>>, Self::Error> {
-        self.0.epoch(group_id.to_vec(), epoch_id)
+        self.0.epoch(group_id.to_vec(), epoch_id).await
     }
 
     async fn write(
@@ -41,16 +41,18 @@ impl mls_rs_core::group::GroupStateStorage for ClientGroupStorage {
         inserts: Vec<mls_rs_core::group::EpochRecord>,
         updates: Vec<mls_rs_core::group::EpochRecord>,
     ) -> Result<(), Self::Error> {
-        self.0.write(
-            state.id,
-            state.data,
-            inserts.into_iter().map(Into::into).collect(),
-            updates.into_iter().map(Into::into).collect(),
-        )
+        self.0
+            .write(
+                state.id,
+                state.data,
+                inserts.into_iter().map(Into::into).collect(),
+                updates.into_iter().map(Into::into).collect(),
+            )
+            .await
     }
 
     async fn max_epoch_id(&self, group_id: &[u8]) -> Result<Option<u64>, Self::Error> {
-        self.0.max_epoch_id(group_id.to_vec())
+        self.0.max_epoch_id(group_id.to_vec()).await
     }
 }
 

mls-rs-uniffi/src/config/group_state.rs

@@ -1,6 +1,9 @@
 use mls_rs::error::IntoAnyError;
 use std::fmt::Debug;
+#[cfg(not(mls_build_async))]
 use std::sync::Mutex;
+#[cfg(mls_build_async)]
+use tokio::sync::Mutex;
 
 use crate::Error;
 
@@ -28,9 +31,13 @@ impl From<EpochRecord> for mls_rs_core::group::EpochRecord {
     }
 }
 
-#[cfg_attr(not(mls_build_async), maybe_async::must_be_sync)]
+// When building for async, uniffi::export has to be applied _after_
+// maybe-async's injection of the async trait. When building for sync,
+// the order has to be the opposite.
+#[cfg_attr(mls_build_async, uniffi::export(with_foreign))]
 #[cfg_attr(mls_build_async, maybe_async::must_be_async)]
-#[uniffi::export(with_foreign)]
+#[cfg_attr(not(mls_build_async), maybe_async::must_be_sync)]
+#[cfg_attr(not(mls_build_async), uniffi::export(with_foreign))]
 pub trait GroupStateStorage: Send + Sync + Debug {
     async fn state(&self, group_id: Vec<u8>) -> Result<Option<Vec<u8>>, Error>;
     async fn epoch(&self, group_id: Vec<u8>, epoch_id: u64) -> Result<Option<Vec<u8>>, Error>;
@@ -59,9 +66,15 @@ impl<S> GroupStateStorageAdapter<S> {
         Self(Mutex::new(group_state_storage))
     }
 
+    #[cfg(not(mls_build_async))]
     fn inner(&self) -> std::sync::MutexGuard<'_, S> {
         self.0.lock().unwrap()
     }
+
+    #[cfg(mls_build_async)]
+    async fn inner(&self) -> tokio::sync::MutexGuard<'_, S> {
+        self.0.lock().await
+    }
 }
 
 #[cfg_attr(not(mls_build_async), maybe_async::must_be_sync)]
@@ -73,13 +86,17 @@ where
 {
     async fn state(&self, group_id: Vec<u8>) -> Result<Option<Vec<u8>>, Error> {
         self.inner()
+            .await
             .state(&group_id)
+            .await
             .map_err(|err| err.into_any_error().into())
     }
 
     async fn epoch(&self, group_id: Vec<u8>, epoch_id: u64) -> Result<Option<Vec<u8>>, Error> {
         self.inner()
+            .await
             .epoch(&group_id, epoch_id)
+            .await
             .map_err(|err| err.into_any_error().into())
     }
 
@@ -91,17 +108,21 @@ where
         epoch_updates: Vec<EpochRecord>,
     ) -> Result<(), Error> {
         self.inner()
+            .await
             .write(
                 mls_rs_core::group::GroupState { id, data },
                 epoch_inserts.into_iter().map(Into::into).collect(),
                 epoch_updates.into_iter().map(Into::into).collect(),
             )
+            .await
             .map_err(|err| err.into_any_error().into())
     }
 
     async fn max_epoch_id(&self, group_id: Vec<u8>) -> Result<Option<u64>, Error> {
         self.inner()
+            .await
             .max_epoch_id(&group_id)
+            .await
             .map_err(|err| err.into_any_error().into())
     }
 }

mls-rs-uniffi/src/lib.rs

@@ -262,6 +262,7 @@ impl TryFrom<mls_rs::CipherSuite> for CipherSuite {
 /// See [`mls_rs::CipherSuiteProvider::signature_key_generate`]
 /// for details.
 #[cfg_attr(not(mls_build_async), maybe_async::must_be_sync)]
+#[cfg_attr(mls_build_async, maybe_async::must_be_async)]
 #[uniffi::export]
 pub async fn generate_signature_keypair(
     cipher_suite: CipherSuite,
@@ -292,6 +293,7 @@ pub struct Client {
 }
 
 #[cfg_attr(not(mls_build_async), maybe_async::must_be_sync)]
+#[cfg_attr(mls_build_async, maybe_async::must_be_async)]
 #[uniffi::export]
 impl Client {
     /// Create a new client.
@@ -495,6 +497,7 @@ pub struct Group {
 }
 
 #[cfg_attr(not(mls_build_async), maybe_async::must_be_sync)]
+#[cfg_attr(mls_build_async, maybe_async::must_be_async)]
 impl Group {
     #[cfg(not(mls_build_async))]
     fn inner(&self) -> std::sync::MutexGuard<'_, mls_rs::Group<UniFFIConfig>> {
@@ -520,6 +523,7 @@ fn index_to_identity(
 
 /// Extract the basic credential identifier from a  from a key package.
 #[cfg_attr(not(mls_build_async), maybe_async::must_be_sync)]
+#[cfg_attr(mls_build_async, maybe_async::must_be_async)]
 async fn signing_identity_to_identifier(
     signing_identity: &identity::SigningIdentity,
 ) -> Result<Vec<u8>, Error> {
@@ -531,6 +535,7 @@ async fn signing_identity_to_identifier(
 }
 
 #[cfg_attr(not(mls_build_async), maybe_async::must_be_sync)]
+#[cfg_attr(mls_build_async, maybe_async::must_be_async)]
 #[uniffi::export]
 impl Group {
     /// Write the current state of the group to storage defined by
@@ -545,8 +550,9 @@ impl Group {
     /// This function is used to provide the current group tree to new
     /// members when `use_ratchet_tree_extension` is set to false in
     /// `ClientConfig`.
-    pub fn export_tree(&self) -> Result<RatchetTree, Error> {
-        self.inner().export_tree().try_into()
+    pub async fn export_tree(&self) -> Result<RatchetTree, Error> {
+        let group = self.inner().await;
+        group.export_tree().try_into()
     }
 
     /// Perform a commit of received proposals (or an empty commit).
@@ -703,8 +709,11 @@ impl Group {
 
 #[cfg(test)]
 mod tests {
+    #[cfg(not(mls_build_async))]
     use super::*;
+    #[cfg(not(mls_build_async))]
     use crate::config::group_state::{EpochRecord, GroupStateStorage};
+    #[cfg(not(mls_build_async))]
     use std::collections::HashMap;
 
     #[test]

mls-rs-uniffi/tests/custom_storage_sync.py

@@ -62,7 +62,7 @@ def max_epoch_id(self, group_id: bytes):
 
 
 group_state_storage = PythonGroupStateStorage()
-client_config = ClientConfig(group_state_storage,
+client_config = ClientConfig(group_state_storage=group_state_storage,
                              use_ratchet_tree_extension=True)
 
 key = generate_signature_keypair(CipherSuite.CURVE25519_AES128)

mls-rs-uniffi/tests/scenarios.rs

@@ -45,9 +45,5 @@ macro_rules! generate_python_tests {
 generate_python_tests!(generate_signature_keypair, None);
 generate_python_tests!(client_config_default_sync, None);
 generate_python_tests!(custom_storage_sync, None);
-
-// TODO(mulmarta): it'll break if we use async trait which will be
-// supported in the next UniFFI release
-// TODO(mgeisler): add back simple_scenario_async
 generate_python_tests!(simple_scenario_sync, None);
 generate_python_tests!(ratchet_tree_sync, None);

mls-rs-uniffi/uniffi-bindgen/Cargo.toml

@@ -7,4 +7,4 @@ publish = false
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-uniffi = { version = "0.26.0", features = ["cli"] }
+uniffi = { git = "https://github.com/mozilla/uniffi-rs/", rev = "6b09f11", version = "0.26.0", features = ["cli"] }