Implement serialize/deserialize for core::net instead of std::net if running rust version newer than 1.77, where core::net was stabilized

serde/build.rs

@@ -15,6 +15,7 @@ fn main() {
 
     if minor >= 77 {
         println!("cargo:rustc-check-cfg=cfg(no_core_cstr)");
+        println!("cargo:rustc-check-cfg=cfg(no_core_net)");
         println!("cargo:rustc-check-cfg=cfg(no_core_num_saturating)");
         println!("cargo:rustc-check-cfg=cfg(no_core_try_from)");
         println!("cargo:rustc-check-cfg=cfg(no_diagnostic_namespace)");
@@ -86,6 +87,12 @@ fn main() {
         println!("cargo:rustc-cfg=no_core_num_saturating");
     }
 
+    // Support for core::net stabilized in Rust 1.77.
+    // https://blog.rust-lang.org/2024/03/21/Rust-1.77.0.html
+    if minor < 77 {
+        println!("cargo:rustc-cfg=no_core_net");
+    }
+
     // Support for the `#[diagnostic]` tool attribute namespace
     // https://blog.rust-lang.org/2024/05/02/Rust-1.78.0.html#diagnostic-attributes
     if minor < 78 {

serde/src/de/impls.rs

@@ -1604,7 +1604,7 @@ macro_rules! parse_ip_impl {
     };
 }
 
-#[cfg(feature = "std")]
+#[cfg(any(feature = "std", not(no_core_net)))]
 macro_rules! variant_identifier {
     (
         $name_kind:ident ($($variant:ident; $bytes:expr; $index:expr),*)
@@ -1679,7 +1679,7 @@ macro_rules! variant_identifier {
     }
 }
 
-#[cfg(feature = "std")]
+#[cfg(any(feature = "std", not(no_core_net)))]
 macro_rules! deserialize_enum {
     (
         $name:ident $name_kind:ident ($($variant:ident; $bytes:expr; $index:expr),*)
@@ -1716,8 +1716,8 @@ macro_rules! deserialize_enum {
     }
 }
 
-#[cfg(feature = "std")]
-#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
+#[cfg(any(feature = "std", not(no_core_net)))]
+#[cfg_attr(docsrs, doc(cfg(any(feature = "std", not(no_core_net)))))]
 impl<'de> Deserialize<'de> for net::IpAddr {
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
     where
@@ -1737,14 +1737,14 @@ impl<'de> Deserialize<'de> for net::IpAddr {
 }
 
 parse_ip_impl! {
-    #[cfg(feature = "std")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "std")))]
+    #[cfg(any(feature = "std", not(no_core_net)))]
+    #[cfg_attr(docsrs, doc(cfg(any(feature = "std", not(no_core_net)))))]
     net::Ipv4Addr, "IPv4 address", 4
 }
 
 parse_ip_impl! {
-    #[cfg(feature = "std")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "std")))]
+    #[cfg(any(feature = "std", not(no_core_net)))]
+    #[cfg_attr(docsrs, doc(cfg(any(feature = "std", not(no_core_net)))))]
     net::Ipv6Addr, "IPv6 address", 16
 }
 
@@ -1770,8 +1770,8 @@ macro_rules! parse_socket_impl {
     };
 }
 
-#[cfg(feature = "std")]
-#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
+#[cfg(any(feature = "std", not(no_core_net)))]
+#[cfg_attr(docsrs, doc(cfg(any(feature = "std", not(no_core_net)))))]
 impl<'de> Deserialize<'de> for net::SocketAddr {
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
     where
@@ -1791,15 +1791,15 @@ impl<'de> Deserialize<'de> for net::SocketAddr {
 }
 
 parse_socket_impl! {
-    #[cfg(feature = "std")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "std")))]
+    #[cfg(any(feature = "std", not(no_core_net)))]
+    #[cfg_attr(docsrs, doc(cfg(any(feature = "std", not(no_core_net)))))]
     net::SocketAddrV4, "IPv4 socket address",
     |(ip, port)| net::SocketAddrV4::new(ip, port),
 }
 
 parse_socket_impl! {
-    #[cfg(feature = "std")]
-    #[cfg_attr(docsrs, doc(cfg(feature = "std")))]
+    #[cfg(any(feature = "std", not(no_core_net)))]
+    #[cfg_attr(docsrs, doc(cfg(any(feature = "std", not(no_core_net)))))]
     net::SocketAddrV6, "IPv6 socket address",
     |(ip, port)| net::SocketAddrV6::new(ip, port, 0, 0),
 }
@@ -3160,13 +3160,13 @@ atomic_impl! {
     AtomicU64 "64"
 }
 
-#[cfg(feature = "std")]
+#[cfg(any(feature = "std", not(no_core_net)))]
 struct FromStrVisitor<T> {
     expecting: &'static str,
     ty: PhantomData<T>,
 }
 
-#[cfg(feature = "std")]
+#[cfg(any(feature = "std", not(no_core_net)))]
 impl<T> FromStrVisitor<T> {
     fn new(expecting: &'static str) -> Self {
         FromStrVisitor {
@@ -3176,7 +3176,7 @@ impl<T> FromStrVisitor<T> {
     }
 }
 
-#[cfg(feature = "std")]
+#[cfg(any(feature = "std", not(no_core_net)))]
 impl<'de, T> Visitor<'de> for FromStrVisitor<T>
 where
     T: str::FromStr,

serde/src/lib.rs

@@ -238,8 +238,13 @@ mod lib {
     #[cfg(feature = "std")]
     pub use std::ffi::CString;
 
+    #[cfg(all(not(no_core_net), not(feature = "std")))]
+    pub use self::core::net;
     #[cfg(feature = "std")]
-    pub use std::{error, net};
+    pub use std::net;
+
+    #[cfg(feature = "std")]
+    pub use std::error;
 
     #[cfg(feature = "std")]
     pub use std::collections::{HashMap, HashSet};

serde/src/ser/impls.rs

@@ -769,20 +769,47 @@ impl Serialize for SystemTime {
 
 ////////////////////////////////////////////////////////////////////////////////
 
+#[cfg(any(feature = "std", not(no_core_net)))]
+struct Wrapper<'a> {
+    pub buf: &'a mut [u8],
+    pub offset: usize,
+}
+
+#[cfg(any(feature = "std", not(no_core_net)))]
+impl<'a> fmt::Write for Wrapper<'a> {
+    fn write_str(&mut self, s: &str) -> fmt::Result {
+        if self.offset > self.buf.len() {
+            return Err(fmt::Error);
+        }
+        let remaining_buf = &mut self.buf[self.offset..];
+        let raw_s = s.as_bytes();
+        let write_num = core::cmp::min(raw_s.len(), remaining_buf.len());
+        remaining_buf[..write_num].copy_from_slice(&raw_s[..write_num]);
+        self.offset += raw_s.len();
+        if write_num < raw_s.len() {
+            Err(fmt::Error)
+        } else {
+            Ok(())
+        }
+    }
+}
+
 /// Serialize a value that implements `Display` as a string, when that string is
 /// statically known to never have more than a constant `MAX_LEN` bytes.
 ///
 /// Panics if the `Display` impl tries to write more than `MAX_LEN` bytes.
-#[cfg(feature = "std")]
+#[cfg(any(feature = "std", not(no_core_net)))]
 macro_rules! serialize_display_bounded_length {
     ($value:expr, $max:expr, $serializer:expr) => {{
         let mut buffer = [0u8; $max];
-        let remaining_len = {
-            let mut remaining = &mut buffer[..];
-            write!(remaining, "{}", $value).unwrap();
-            remaining.len()
+        let written_len = {
+            let mut w = Wrapper {
+                buf: &mut buffer,
+                offset: 0,
+            };
+            write!(&mut w, "{}", $value).unwrap();
+            w.offset
         };
-        let written_len = buffer.len() - remaining_len;
         let written = &buffer[..written_len];
 
         // write! only provides fmt::Formatter to Display implementations, which
@@ -793,8 +820,8 @@ macro_rules! serialize_display_bounded_length {
     }};
 }
 
-#[cfg(feature = "std")]
-#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
+#[cfg(any(feature = "std", not(no_core_net)))]
+#[cfg_attr(docsrs, doc(cfg(any(feature = "std", not(no_core_net)))))]
 impl Serialize for net::IpAddr {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -818,7 +845,7 @@ impl Serialize for net::IpAddr {
     }
 }
 
-#[cfg(feature = "std")]
+#[cfg(any(feature = "std", not(no_core_net)))]
 const DEC_DIGITS_LUT: &[u8] = b"\
       0001020304050607080910111213141516171819\
       2021222324252627282930313233343536373839\
@@ -826,7 +853,7 @@ const DEC_DIGITS_LUT: &[u8] = b"\
       6061626364656667686970717273747576777879\
       8081828384858687888990919293949596979899";
 
-#[cfg(feature = "std")]
+#[cfg(any(feature = "std", not(no_core_net)))]
 #[inline]
 fn format_u8(mut n: u8, out: &mut [u8]) -> usize {
     if n >= 100 {
@@ -847,7 +874,7 @@ fn format_u8(mut n: u8, out: &mut [u8]) -> usize {
     }
 }
 
-#[cfg(feature = "std")]
+#[cfg(any(feature = "std", not(no_core_net)))]
 #[test]
 fn test_format_u8() {
     let mut i = 0u8;
@@ -864,8 +891,8 @@ fn test_format_u8() {
     }
 }
 
-#[cfg(feature = "std")]
-#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
+#[cfg(any(feature = "std", not(no_core_net)))]
+#[cfg_attr(docsrs, doc(cfg(any(feature = "std", not(no_core_net)))))]
 impl Serialize for net::Ipv4Addr {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -889,8 +916,8 @@ impl Serialize for net::Ipv4Addr {
     }
 }
 
-#[cfg(feature = "std")]
-#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
+#[cfg(any(feature = "std", not(no_core_net)))]
+#[cfg_attr(docsrs, doc(cfg(any(feature = "std", not(no_core_net)))))]
 impl Serialize for net::Ipv6Addr {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -906,8 +933,8 @@ impl Serialize for net::Ipv6Addr {
     }
 }
 
-#[cfg(feature = "std")]
-#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
+#[cfg(any(feature = "std", not(no_core_net)))]
+#[cfg_attr(docsrs, doc(cfg(any(feature = "std", not(no_core_net)))))]
 impl Serialize for net::SocketAddr {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -931,8 +958,8 @@ impl Serialize for net::SocketAddr {
     }
 }
 
-#[cfg(feature = "std")]
-#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
+#[cfg(any(feature = "std", not(no_core_net)))]
+#[cfg_attr(docsrs, doc(cfg(any(feature = "std", not(no_core_net)))))]
 impl Serialize for net::SocketAddrV4 {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where
@@ -948,8 +975,8 @@ impl Serialize for net::SocketAddrV4 {
     }
 }
 
-#[cfg(feature = "std")]
-#[cfg_attr(docsrs, doc(cfg(feature = "std")))]
+#[cfg(any(feature = "std", not(no_core_net)))]
+#[cfg_attr(docsrs, doc(cfg(any(feature = "std", not(no_core_net)))))]
 impl Serialize for net::SocketAddrV6 {
     fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
     where