ffi: Expose CiphertextMessageType constants

rust/bridge/ffi/Cargo.toml

@@ -12,8 +12,7 @@ crate-type = ["staticlib"]
 libsignal-protocol-rust = { path = "../../protocol" }
 rand = "0.7.3"
 libc = "0.2"
-num-traits = "0.2"
-num-derive = "0.3"
+static_assertions = "1.1"
 
 [build-dependencies]
 cbindgen = "0.14"

rust/bridge/ffi/cbindgen.toml

@@ -10,7 +10,7 @@ autogen_warning = "/* This file was automatically generated by cbindgen */"
 prefix_with_name = true
 
 [export]
-include = ["SignalErrorCode", "FfiDirection"]
+include = ["SignalErrorCode", "FfiDirection", "FfiCiphertextMessageType"]
 prefix = "Signal"
 renaming_overrides_prefixing = true
 
@@ -21,6 +21,7 @@ renaming_overrides_prefixing = true
 "FfiSignedPreKeyStoreStruct" = "SignalSignedPreKeyStore"
 "FfiSenderKeyStoreStruct" = "SignalSenderKeyStore"
 "FfiDirection" = "SignalDirection"
+"FfiCiphertextMessageType" = "SignalCiphertextMessageType"
 
 # Avoid double-prefixing these
 "SignalFfiError" = "SignalFfiError"

rust/bridge/ffi/src/lib.rs

@@ -10,7 +10,7 @@
 
 use libc::{c_char, c_int, c_uchar, c_uint, c_ulonglong, size_t};
 use libsignal_protocol_rust::*;
-use num_derive::ToPrimitive;
+use static_assertions::const_assert_eq;
 use std::convert::TryFrom;
 use std::ffi::{c_void, CString};
 
@@ -63,7 +63,7 @@ pub unsafe extern "C" fn signal_error_get_type(err: *const SignalFfiError) -> u3
     match err.as_ref() {
         Some(err) => {
             let code: SignalErrorCode = err.into();
-            num_traits::ToPrimitive::to_u32(&code).expect("Error enum can be converted to u32")
+            code as u32
         }
         None => 0,
     }
@@ -806,7 +806,7 @@ type IsTrustedIdentity = extern "C" fn(
     ctx: *mut c_void,
 ) -> c_int;
 
-#[derive(Debug, ToPrimitive)]
+#[derive(Debug)]
 #[repr(C)]
 pub enum FfiDirection {
     Sending = 0,
@@ -909,12 +909,11 @@ impl IdentityKeyStore for FfiIdentityKeyStore {
             Direction::Sending => FfiDirection::Sending,
             Direction::Receiving => FfiDirection::Receiving,
         };
-        let primitive_direction = num_traits::ToPrimitive::to_u32(&direction).unwrap();
         let result = (self.store.is_trusted_identity)(
             self.store.ctx,
             &*address,
             &*identity.public_key(),
-            primitive_direction,
+            direction as u32,
             ctx,
         );
 
@@ -1284,14 +1283,40 @@ pub unsafe extern "C" fn signal_encrypt_message(
 
 ffi_fn_destroy!(signal_ciphertext_message_destroy destroys CiphertextMessage);
 
+#[derive(Debug)]
+#[repr(C)]
+pub enum FfiCiphertextMessageType {
+    Whisper = 2,
+    PreKey = 3,
+    SenderKey = 4,
+    SenderKeyDistribution = 5,
+}
+
+const_assert_eq!(
+    FfiCiphertextMessageType::Whisper as u8,
+    CiphertextMessageType::Whisper as u8
+);
+const_assert_eq!(
+    FfiCiphertextMessageType::PreKey as u8,
+    CiphertextMessageType::PreKey as u8
+);
+const_assert_eq!(
+    FfiCiphertextMessageType::SenderKey as u8,
+    CiphertextMessageType::SenderKey as u8
+);
+const_assert_eq!(
+    FfiCiphertextMessageType::SenderKeyDistribution as u8,
+    CiphertextMessageType::SenderKeyDistribution as u8
+);
+
 #[no_mangle]
 pub unsafe extern "C" fn signal_ciphertext_message_type(
     typ: *mut u8,
     msg: *const CiphertextMessage,
 ) -> *mut SignalFfiError {
     run_ffi_safe(|| {
         let msg = native_handle_cast::<CiphertextMessage>(msg)?;
-        *typ = msg.message_type().encoding();
+        *typ = msg.message_type() as u8;
         Ok(())
     })
 }

rust/bridge/ffi/src/util.rs

@@ -7,7 +7,6 @@
 
 use libc::{c_char, c_uchar, c_uint, c_ulonglong, size_t};
 use libsignal_protocol_rust::*;
-use num_derive::ToPrimitive;
 use std::ffi::{CStr, CString};
 use std::fmt;
 
@@ -22,7 +21,7 @@ pub enum SignalFfiError {
     InvalidType,
 }
 
-#[derive(Debug, ToPrimitive)]
+#[derive(Debug)]
 #[repr(C)]
 pub enum SignalErrorCode {
     UnknownError = 1,

rust/protocol/src/protocol.rs

@@ -28,21 +28,10 @@ pub enum CiphertextMessage {
 
 #[derive(Copy, Clone, Eq, PartialEq, Debug)]
 pub enum CiphertextMessageType {
-    Whisper,
-    PreKey,
-    SenderKey,
-    SenderKeyDistribution,
-}
-
-impl CiphertextMessageType {
-    pub fn encoding(&self) -> u8 {
-        match self {
-            CiphertextMessageType::Whisper => 2,
-            CiphertextMessageType::PreKey => 3,
-            CiphertextMessageType::SenderKey => 4,
-            CiphertextMessageType::SenderKeyDistribution => 5,
-        }
-    }
+    Whisper = 2,
+    PreKey = 3,
+    SenderKey = 4,
+    SenderKeyDistribution = 5,
 }
 
 impl CiphertextMessage {

swift/Sources/SignalClient/messages/CiphertextMessage.swift

@@ -3,6 +3,30 @@ import SignalFfi
 public class CiphertextMessage {
     private var handle: OpaquePointer?
 
+    public struct MessageType: RawRepresentable, Hashable {
+        public var rawValue: UInt8
+        public init(rawValue: UInt8) {
+            self.rawValue = rawValue
+        }
+
+        internal init(_ knownType: SignalCiphertextMessageType) {
+            self.init(rawValue: UInt8(knownType.rawValue))
+        }
+
+        public static var whisper: Self {
+            return Self(SignalCiphertextMessageType_Whisper)
+        }
+        public static var preKey: Self {
+            return Self(SignalCiphertextMessageType_PreKey)
+        }
+        public static var senderKey: Self {
+            return Self(SignalCiphertextMessageType_SenderKey)
+        }
+        public static var senderKeyDistribution: Self {
+            return Self(SignalCiphertextMessageType_SenderKeyDistribution)
+        }
+    }
+
     deinit {
         signal_ciphertext_message_destroy(handle)
     }
@@ -17,9 +41,9 @@ public class CiphertextMessage {
         }
     }
 
-    public func messageType() throws -> UInt8 {
-        return try invokeFnReturningInteger {
+    public func messageType() throws -> MessageType {
+        return MessageType(rawValue: try invokeFnReturningInteger {
             signal_ciphertext_message_type($0, handle)
-        }
+        })
     }
 }

swift/Tests/SignalClientTests/PublicAPITests.swift

@@ -279,7 +279,7 @@ class PublicAPITests: XCTestCase {
                                          identityStore: alice_store,
                                          context: nil)
 
-        XCTAssertEqual(try! ctext_a.messageType(), 3); // prekey
+        XCTAssertEqual(try! ctext_a.messageType(), .preKey)
 
         let ctext_b = try! PreKeySignalMessage(bytes: try! ctext_a.serialize())
 
@@ -302,7 +302,7 @@ class PublicAPITests: XCTestCase {
                                           identityStore: bob_store,
                                           context: nil)
 
-        XCTAssertEqual(try! ctext2_b.messageType(), 2); // normal message
+        XCTAssertEqual(try! ctext2_b.messageType(), .whisper)
 
         let ctext2_a = try! SignalMessage(bytes: try! ctext2_b.serialize())