Add SockAddr::set_length

src/sockaddr.rs

@@ -25,16 +25,6 @@ pub struct SockAddr {
 
 #[allow(clippy::len_without_is_empty)]
 impl SockAddr {
-    /// Constructs a `SockAddr` with the family `AF_UNIX` and the provided path.
-    ///
-    /// Returns an error if the path is longer than `SUN_LEN`.
-    pub fn unix<P>(path: P) -> io::Result<SockAddr>
-    where
-        P: AsRef<Path>,
-    {
-        crate::sys::unix_sockaddr(path.as_ref())
-    }
-
     /// Create a `SockAddr` from the underlying storage and its length.
     ///
     /// # Safety
@@ -153,6 +143,26 @@ impl SockAddr {
         })
     }
 
+    /// Constructs a `SockAddr` with the family `AF_UNIX` and the provided path.
+    ///
+    /// Returns an error if the path is longer than `SUN_LEN`.
+    pub fn unix<P>(path: P) -> io::Result<SockAddr>
+    where
+        P: AsRef<Path>,
+    {
+        crate::sys::unix_sockaddr(path.as_ref())
+    }
+
+    /// Set the length of the address.
+    ///
+    /// # Safety
+    ///
+    /// Caller must ensure that the address up to `length` bytes are properly
+    /// initialised.
+    pub unsafe fn set_length(&mut self, length: socklen_t) {
+        self.len = length;
+    }
+
     /// Returns this address's family.
     pub const fn family(&self) -> sa_family_t {
         self.storage.ss_family
@@ -250,6 +260,14 @@ impl SockAddr {
             _ => None,
         }
     }
+
+    /// Returns the initialised storage bytes.
+    fn as_bytes(&self) -> &[u8] {
+        // SAFETY: `self.storage` is a C struct which can always be treated a
+        // slice of bytes. Futhermore we ensure we don't read any unitialised
+        // bytes by using `self.len`.
+        unsafe { std::slice::from_raw_parts(self.as_ptr().cast(), self.len as usize) }
+    }
 }
 
 impl From<SocketAddr> for SockAddr {
@@ -329,29 +347,18 @@ impl fmt::Debug for SockAddr {
 
 impl PartialEq for SockAddr {
     fn eq(&self, other: &Self) -> bool {
-        unsafe {
-            let these_bytes: &[u8] = any_as_u8_slice(&self.storage, self.len as usize);
-            let those_bytes: &[u8] = any_as_u8_slice(&other.storage, other.len as usize);
-            these_bytes == those_bytes
-        }
+        self.as_bytes() == other.as_bytes()
     }
 }
 
 impl Eq for SockAddr {}
 
 impl Hash for SockAddr {
     fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
-        unsafe {
-            let these_bytes: &[u8] = any_as_u8_slice(&self.storage, self.len as usize);
-            these_bytes.hash(state);
-        }
+        self.as_bytes().hash(state);
     }
 }
 
-unsafe fn any_as_u8_slice<T: Sized>(p: &T, size: usize) -> &[u8] {
-    ::std::slice::from_raw_parts((p as *const T) as *const u8, size)
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;