Implement Any::pack,is,unpack operations

Author: stepancheg

protobuf-test/src/common/v2/test_any.rs

@@ -0,0 +1,38 @@
+use super::test_any_pb::MessageOne;
+use super::test_any_pb::MessageTwo;
+use protobuf::well_known_types::Any;
+use protobuf::Message;
+
+#[test]
+fn test_static() {
+    let mut m1 = MessageOne::new();
+    m1.set_i(10);
+    let any = Any::pack(&m1).unwrap();
+    assert_eq!("type.googleapis.com/test_any.MessageOne", any.type_url);
+    assert!(any.is::<MessageOne>());
+    assert!(!any.is::<MessageTwo>());
+    assert_eq!(Some(m1), any.unpack::<MessageOne>().unwrap());
+    assert_eq!(None, any.unpack::<MessageTwo>().unwrap());
+}
+
+#[test]
+fn test_dynamic() {
+    let mut m1 = MessageOne::new();
+    m1.set_i(10);
+    let any = Any::pack_dyn(&m1).unwrap();
+    assert_eq!("type.googleapis.com/test_any.MessageOne", any.type_url);
+    assert!(any.is_dyn(MessageOne::descriptor_static()));
+    assert!(!any.is_dyn(MessageTwo::descriptor_static()));
+    assert_eq!(
+        m1,
+        *any.unpack_dyn(MessageOne::descriptor_static())
+            .unwrap()
+            .unwrap()
+            .downcast_box::<MessageOne>()
+            .unwrap()
+    );
+    assert!(any
+        .unpack_dyn(MessageTwo::descriptor_static())
+        .unwrap()
+        .is_none());
+}

protobuf-test/src/common/v2/test_any_pb.proto

@@ -0,0 +1,14 @@
+syntax = "proto2";
+
+import "rustproto.proto";
+option (rustproto.generate_accessors_all) = true;
+
+package test_any;
+
+message MessageOne {
+    optional int32 i = 1;
+}
+
+message MessageTwo {
+
+}

protobuf/src/any.rs

@@ -0,0 +1,114 @@
+use crate::parse_from_bytes;
+use crate::reflect::MessageDescriptor;
+use crate::well_known_types::Any;
+use crate::Message;
+use crate::ProtobufResult;
+
+impl Any {
+    fn get_type_url(type_url_prefix: &str, descriptor: &MessageDescriptor) -> String {
+        format!("{}/{}", type_url_prefix, descriptor.full_name())
+    }
+
+    fn get_type_name_from_type_url(type_url: &str) -> Option<&str> {
+        match type_url.rfind('/') {
+            Some(i) => Some(&type_url[i + 1..]),
+            None => None,
+        }
+    }
+
+    /// Pack any message into `well_known_types::Any` value.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// # use protobuf::Message;
+    /// # use protobuf::ProtobufResult;
+    /// use protobuf::well_known_types::Any;
+    ///
+    /// # fn the_test<MyMessage: Message>(message: &MyMessage) -> ProtobufResult<()> {
+    /// let message: &MyMessage = message;
+    /// let any = Any::pack(message)?;
+    /// assert!(any.is::<MyMessage>());
+    /// #   Ok(())
+    /// # }
+    /// ```
+    pub fn pack<M: Message>(message: &M) -> ProtobufResult<Any> {
+        Any::pack_dyn(message)
+    }
+
+    /// Pack any message into `well_known_types::Any` value.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use protobuf::Message;
+    /// # use protobuf::ProtobufResult;
+    /// use protobuf::well_known_types::Any;
+    ///
+    /// # fn the_test(message: &dyn Message) -> ProtobufResult<()> {
+    /// let message: &dyn Message = message;
+    /// let any = Any::pack_dyn(message)?;
+    /// assert!(any.is_dyn(message.descriptor()));
+    /// #   Ok(())
+    /// # }
+    /// ```
+    pub fn pack_dyn(message: &dyn Message) -> ProtobufResult<Any> {
+        Any::pack_with_type_url_prefix(message, "type.googleapis.com")
+    }
+
+    fn pack_with_type_url_prefix(
+        message: &dyn Message,
+        type_url_prefix: &str,
+    ) -> ProtobufResult<Any> {
+        Ok(Any {
+            type_url: Any::get_type_url(type_url_prefix, message.descriptor()),
+            value: message.write_to_bytes()?,
+            ..Default::default()
+        })
+    }
+
+    /// Check if `Any` contains a message of given type.
+    pub fn is<M: Message>(&self) -> bool {
+        self.is_dyn(M::descriptor_static())
+    }
+
+    /// Check if `Any` contains a message of given type.
+    pub fn is_dyn(&self, descriptor: &MessageDescriptor) -> bool {
+        match Any::get_type_name_from_type_url(&self.type_url) {
+            Some(type_name) => type_name == descriptor.full_name(),
+            None => false,
+        }
+    }
+
+    /// Extract a message from this `Any`.
+    ///
+    /// # Returns
+    ///
+    /// * `Ok(None)` when message type mismatch
+    /// * `Err` when parse failed
+    pub fn unpack<M: Message>(&self) -> ProtobufResult<Option<M>> {
+        if !self.is::<M>() {
+            return Ok(None);
+        }
+        Ok(Some(parse_from_bytes(&self.value)?))
+    }
+
+    /// Extract a message from this `Any`.
+    ///
+    /// # Returns
+    ///
+    /// * `Ok(None)` when message type mismatch
+    /// * `Err` when parse failed
+    pub fn unpack_dyn(
+        &self,
+        descriptor: &MessageDescriptor,
+    ) -> ProtobufResult<Option<Box<dyn Message>>> {
+        if !self.is_dyn(descriptor) {
+            return Ok(None);
+        }
+        let mut message = descriptor.new_instance();
+        message.merge_from_bytes(&self.value)?;
+        message.check_initialized()?;
+        Ok(Some(message))
+    }
+}

protobuf/src/lib.rs

@@ -47,6 +47,8 @@ pub mod descriptor;
 pub mod plugin;
 pub mod rustproto;
 
+mod any;
+
 mod clear;
 mod core;
 mod enums;