From 9cf577d9bcebc36e64660580c4b13a986f21b279 Mon Sep 17 00:00:00 2001
From: Victor Koenders <gpg@trangar.com>
Date: Sat, 16 Oct 2021 13:19:30 +0200
Subject: [PATCH] Added support for String, Mutex<T> and RwLock<T>

---
 src/error.rs               |  7 ++++++
 src/features/impl_alloc.rs | 15 +++++++++++-
 src/features/impl_std.rs   | 49 +++++++++++++++++++++++++++++++++++++-
 tests/alloc.rs             |  1 +
 tests/std.rs               | 16 +++++++++++--
 5 files changed, 84 insertions(+), 4 deletions(-)

diff --git a/src/error.rs b/src/error.rs
index 5884c1b..e466120 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -23,6 +23,13 @@ pub enum EncodeError {
         /// The amount of bytes that were written before the error occured
         index: usize,
     },
+
+    /// The encoder tried to encode a `Mutex` or `RwLock`, but the locking failed
+    #[cfg(feature = "std")]
+    LockFailed {
+        /// The type name of the mutex for debugging purposes
+        type_name: &'static str,
+    },
 }
 
 /// Errors that can be encounted by decoding a type
diff --git a/src/features/impl_alloc.rs b/src/features/impl_alloc.rs
index 30e707a..4132a2f 100644
--- a/src/features/impl_alloc.rs
+++ b/src/features/impl_alloc.rs
@@ -5,7 +5,7 @@ use crate::{
     error::{DecodeError, EncodeError},
     Config,
 };
-use alloc::{borrow::Cow, boxed::Box, collections::*, rc::Rc, sync::Arc, vec::Vec};
+use alloc::{borrow::Cow, boxed::Box, collections::*, rc::Rc, string::String, sync::Arc, vec::Vec};
 
 #[derive(Default)]
 struct VecWriter {
@@ -178,6 +178,19 @@ where
     }
 }
 
+impl Decodable for String {
+    fn decode<D: Decode>(decoder: D) -> Result<Self, DecodeError> {
+        let bytes = Vec::<u8>::decode(decoder)?;
+        String::from_utf8(bytes).map_err(|e| DecodeError::Utf8(e.utf8_error()))
+    }
+}
+
+impl Encodeable for String {
+    fn encode<E: Encode>(&self, encoder: E) -> Result<(), EncodeError> {
+        self.as_bytes().encode(encoder)
+    }
+}
+
 impl<T> Decodable for Box<T>
 where
     T: Decodable,
diff --git a/src/features/impl_std.rs b/src/features/impl_std.rs
index 4099208..cd9bff4 100644
--- a/src/features/impl_std.rs
+++ b/src/features/impl_std.rs
@@ -4,7 +4,10 @@ use crate::{
     enc::{write::Writer, Encode, Encodeable, Encoder},
     error::{DecodeError, EncodeError},
 };
-use std::ffi::{CStr, CString};
+use std::{
+    ffi::{CStr, CString},
+    sync::{Mutex, RwLock},
+};
 
 /// Decode type `D` from the given reader. The reader can be any type that implements `std::io::Read`, e.g. `std::fs::File`.
 pub fn decode_from<D: Decodable, R: std::io::Read>(src: &mut R) -> Result<D, DecodeError> {
@@ -105,3 +108,47 @@ impl Decodable for CString {
         Ok(cstr.into())
     }
 }
+
+impl<T> Encodeable for Mutex<T>
+where
+    T: Encodeable,
+{
+    fn encode<E: Encode>(&self, encoder: E) -> Result<(), EncodeError> {
+        let t = self.lock().map_err(|_| EncodeError::LockFailed {
+            type_name: core::any::type_name::<Mutex<T>>(),
+        })?;
+        t.encode(encoder)
+    }
+}
+
+impl<T> Decodable for Mutex<T>
+where
+    T: Decodable,
+{
+    fn decode<D: Decode>(decoder: D) -> Result<Self, DecodeError> {
+        let t = T::decode(decoder)?;
+        Ok(Mutex::new(t))
+    }
+}
+
+impl<T> Encodeable for RwLock<T>
+where
+    T: Encodeable,
+{
+    fn encode<E: Encode>(&self, encoder: E) -> Result<(), EncodeError> {
+        let t = self.read().map_err(|_| EncodeError::LockFailed {
+            type_name: core::any::type_name::<Mutex<T>>(),
+        })?;
+        t.encode(encoder)
+    }
+}
+
+impl<T> Decodable for RwLock<T>
+where
+    T: Decodable,
+{
+    fn decode<D: Decode>(decoder: D) -> Result<Self, DecodeError> {
+        let t = T::decode(decoder)?;
+        Ok(RwLock::new(t))
+    }
+}
diff --git a/tests/alloc.rs b/tests/alloc.rs
index f096b5f..211284a 100644
--- a/tests/alloc.rs
+++ b/tests/alloc.rs
@@ -48,6 +48,7 @@ fn test_vec() {
 #[test]
 fn test_alloc_commons() {
     the_same::<Vec<u32>>(vec![1, 2, 3, 4, 5]);
+    the_same(String::from("Hello world"));
     the_same(Box::<u32>::new(5));
     the_same(Box::<[u32]>::from(vec![1, 2, 3, 4, 5]));
     the_same(Cow::<u32>::Owned(5));
diff --git a/tests/std.rs b/tests/std.rs
index d9365a2..7646a4a 100644
--- a/tests/std.rs
+++ b/tests/std.rs
@@ -2,6 +2,8 @@
 
 mod utils;
 
+use std::sync::{Mutex, RwLock};
+
 use utils::the_same;
 
 struct Foo {
@@ -60,10 +62,20 @@ fn test_std_commons() {
     the_same(CString::new("Hello world").unwrap());
 
     let config = bincode::config::Default;
-    let cstr = CStr::from_bytes_with_nul(b"Hello world\0").unwrap();
     let mut buffer = [0u8; 1024];
+
+    let cstr = CStr::from_bytes_with_nul(b"Hello world\0").unwrap();
     let len = bincode::encode_into_slice_with_config(cstr, &mut buffer, config).unwrap();
     let decoded: &CStr = bincode::decode_with_config(&mut buffer[..len], config).unwrap();
-
     assert_eq!(cstr, decoded);
+
+    let mutex = Mutex::new("Hello world".to_string());
+    let len = bincode::encode_into_slice_with_config(&mutex, &mut buffer, config).unwrap();
+    let decoded: Mutex<String> = bincode::decode_with_config(&mut buffer[..len], config).unwrap();
+    assert_eq!(&*mutex.lock().unwrap(), &*decoded.lock().unwrap());
+
+    let rwlock = RwLock::new("Hello world".to_string());
+    let len = bincode::encode_into_slice_with_config(&mutex, &mut buffer, config).unwrap();
+    let decoded: RwLock<String> = bincode::decode_with_config(&mut buffer[..len], config).unwrap();
+    assert_eq!(&*rwlock.read().unwrap(), &*decoded.read().unwrap());
 }