Pfthb

I got an issue while implement serializing/deserializing and sizing functionalities on a struct that have complex data types like Arc pointers Mutex locks. First I've resolved these Arc and Mutex serialization/deserialization problem using this topic:

How do I serialize or deserialize an Arc<T> in Serde?

but now, I got stuck on implementing ser/desr and sizing for Any and Send traits, and I have neither an idea nor a compiling example to solve this issue.

Code is here:

#[macro_use]
extern crate serde_derive;
extern crate serde;
extern crate serde_json;

use serde::Serialize;
use std::sync::Mutex;
use std::sync::Arc;
use std::any::Any;

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Message 
 pub id: u64,
 pub data: Arc<Mutex<Any + Send>>,


#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Data 
 pub name: String,


impl Data 
 fn new(name_parameter: String) -> Data 
 let data = Data 
 name: name_parameter,
 ;
 data
 


fn main() 
 let msg: Message = Message id: 23, data: (Arc::new(Mutex::new(Data::new(String::from("TesData"))))) ;
 let ser_msg = serde_json::to_string(&msg).unwrap();
 let des_msg: Message = serde_json::from_str(&ser_msg).unwrap();

 println!(":?", msg);
 println!(":?", ser_msg);
 println!(":?", des_msg);

Here is the code in the Playground

It gives the following errors:

error[E0277]: the size for values of type `(dyn std::any::Any + std::marker::Send + 'static)` cannot be known at compilation time
 --> src/main.rs:15:5
 |
15 | pub data: Arc<Mutex<Any + Send>>,
 | ^^^ doesn't have a size known at compile-time
 |
 = help: the trait `std::marker::Sized` is not implemented for `(dyn std::any::Any + std::marker::Send + 'static)`
 = note: to learn more, visit <https://doc.rust-lang.org/book/second-edition/ch19-04-advanced-types.html#dynamically-sized-types-and-the-sized-trait>
 = note: required because of the requirements on the impl of `serde::Serialize` for `std::sync::Mutex<(dyn std::any::Any + std::marker::Send + 'static)>`
 = note: required because of the requirements on the impl of `serde::Serialize` for `std::sync::Arc<std::sync::Mutex<(dyn std::any::Any + std::marker::Send + 'static)>>`
 = note: required by `serde::ser::SerializeStruct::serialize_field`

error[E0277]: the trait bound `(dyn std::any::Any + std::marker::Send + 'static): serde::Serialize` is not satisfied
 --> src/main.rs:15:5
 |
15 | pub data: Arc<Mutex<Any + Send>>,
 | ^^^ the trait `serde::Serialize` is not implemented for `(dyn std::any::Any + std::marker::Send + 'static)`
 |
 = note: required because of the requirements on the impl of `serde::Serialize` for `std::sync::Mutex<(dyn std::any::Any + std::marker::Send + 'static)>`
 = note: required because of the requirements on the impl of `serde::Serialize` for `std::sync::Arc<std::sync::Mutex<(dyn std::any::Any + std::marker::Send + 'static)>>`
 = note: required by `serde::ser::SerializeStruct::serialize_field`

error[E0277]: the trait bound `(dyn std::any::Any + std::marker::Send + 'static): serde::Deserialize<'_>` is not satisfied
 --> src/main.rs:15:5
 |
15 | pub data: Arc<Mutex<Any + Send>>,
 | ^^^ the trait `serde::Deserialize<'_>` is not implemented for `(dyn std::any::Any + std::marker::Send + 'static)`

You can use this solution as a work around but it should work it out for you i guess.

You have to access the data: Arc<Mutex<Any + Send>> then serialize/deserialze data and id separately.

#[macro_use]
extern crate serde_derive;
extern crate serde;
extern crate serde_json;

use serde::Serialize;
use std::sync::Mutex;
use std::sync::Arc;
use std::any::Any;

#[derive(Debug, Clone)]
pub struct Message 
 pub id: u64,
 pub data: Arc<Mutex<Any + Send>>,


#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Data 
 pub name: String,


impl Data 
 fn new(name_parameter: String) -> Data 
 let data = Data 
 name: name_parameter,
 ;
 data
 


fn main() 
 let msg: Message = Message id: 23, data: (Arc::new(Mutex::new(Data::new(String::from("TesData"))))) ;
 let _id = msg.id;
 let guard = msg.data.lock().unwrap();
 let msg_data: Option<&Data> = guard.downcast_ref::<Data>();
 let ser_msg_data = serde_json::to_string(&msg_data).unwrap();
 let des_msg_data: Data = serde_json::from_str(&ser_msg_data).unwrap();
 println!(":?", des_msg_data);
 let des_msg:Message = Message id : _id, data: Arc::new(Mutex::new(des_msg_data));
 println!(":?", msg);
 println!(":?", ser_msg_data);
 println!(":?", des_msg);

Here is the playground.
Playground