Add Deserialize impl for CStr

Fixes #810

serde/src/de/impls.rs

@@ -27,6 +27,8 @@ use std::path;
 use core::str;
 #[cfg(feature = "std")]
 use std::ffi::CString;
+#[cfg(all(feature = "std", feature="unstable"))]
+use std::ffi::CStr;
 
 #[cfg(feature = "std")]
 use std::rc::Rc;
@@ -300,6 +302,16 @@ impl Deserialize for String {
 
 ///////////////////////////////////////////////////////////////////////////////
 
+#[cfg(all(feature = "std", feature="unstable"))]
+impl Deserialize for Box<CStr> {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+        where D: Deserializer
+    {
+        let s = try!(CString::deserialize(deserializer));
+        Ok(s.into_boxed_c_str())
+    }
+}
+
 #[cfg(feature = "std")]
 impl Deserialize for CString {
     fn deserialize<D>(deserializer: D) -> Result<CString, D::Error>

serde/src/lib.rs

@@ -61,7 +61,7 @@
 
 #![doc(html_root_url="https://docs.serde.rs")]
 #![cfg_attr(not(feature = "std"), no_std)]
-#![cfg_attr(feature = "unstable", feature(inclusive_range, nonzero, specialization, zero_one))]
+#![cfg_attr(feature = "unstable", feature(inclusive_range, nonzero, specialization, zero_one, into_boxed_c_str))]
 #![cfg_attr(feature = "alloc", feature(alloc))]
 #![cfg_attr(feature = "collections", feature(collections))]
 #![cfg_attr(feature = "cargo-clippy", allow(linkedlist, type_complexity, doc_markdown))]

test_suite/tests/test_de.rs

@@ -8,6 +8,9 @@ use std::time::Duration;
 use std::default::Default;
 use std::ffi::CString;
 
+#[cfg(feature = "unstable")]
+use std::ffi::CStr;
+
 extern crate serde;
 use serde::Deserialize;
 
@@ -886,6 +889,13 @@ declare_tests! {
     }
 }
 
+#[cfg(feature = "unstable")]
+#[test]
+fn test_cstr() {
+    assert_de_tokens::<Box<CStr>>(&CString::new("abc").unwrap().into_boxed_c_str(),
+                                  &[Token::Bytes(b"abc")]);
+}
+
 #[cfg(feature = "unstable")]
 #[test]
 fn test_net_ipaddr() {
@@ -895,6 +905,28 @@ fn test_net_ipaddr() {
     );
 }
 
+#[cfg(feature = "unstable")]
+#[test]
+fn test_cstr_internal_null() {
+    assert_de_tokens_error::<Box<CStr>>(
+        &[
+            Token::Bytes(b"a\0c"),
+        ],
+        Error::Message("nul byte found in provided data at position: 1".into())
+    );
+}
+
+#[cfg(feature = "unstable")]
+#[test]
+fn test_cstr_internal_null_end() {
+    assert_de_tokens_error::<Box<CStr>>(
+        &[
+            Token::Bytes(b"ac\0"),
+        ],
+        Error::Message("nul byte found in provided data at position: 2".into())
+    );
+}
+
 declare_error_tests! {
     test_unknown_field<StructDenyUnknown> {
         &[