Rollup merge of #41135 - japaric:unstable-docs, r=steveklabnik

[rust.git] / src / libstd / ffi / c_str.rs

diff --git a/src/libstd/ffi/c_str.rs b/src/libstd/ffi/c_str.rs
index bfb0aa6e1a122410e6fe6acfd1e9b612e2c76710..fc1b9a976322ea50e4580380368cd437a39bcc08 100644 (file)
--- a/src/libstd/ffi/c_str.rs
+++ b/src/libstd/ffi/c_str.rs
@@ -325,7 +325,7 @@ pub fn as_bytes_with_nul(&self) -> &[u8] {
     }
 
     /// Converts this `CString` into a boxed `CStr`.
-    #[unstable(feature = "into_boxed_c_str", issue = "0")]
+    #[unstable(feature = "into_boxed_c_str", issue = "40380")]
     pub fn into_boxed_c_str(self) -> Box<CStr> {
         unsafe { mem::transmute(self.into_inner()) }
     }
@@ -356,7 +356,7 @@ impl ops::Deref for CString {
     type Target = CStr;
 
     fn deref(&self) -> &CStr {
-        unsafe { mem::transmute(self.as_bytes_with_nul()) }
+        unsafe { CStr::from_bytes_with_nul_unchecked(self.as_bytes_with_nul()) }
     }
 }
 
@@ -415,6 +415,20 @@ fn from(s: &'a CStr) -> Box<CStr> {
     }
 }
 
+#[stable(feature = "c_string_from_box", since = "1.17.0")]
+impl From<Box<CStr>> for CString {
+    fn from(s: Box<CStr>) -> CString {
+        s.into_c_string()
+    }
+}
+
+#[stable(feature = "box_from_c_string", since = "1.17.0")]
+impl Into<Box<CStr>> for CString {
+    fn into(self) -> Box<CStr> {
+        self.into_boxed_c_str()
+    }
+}
+
 #[stable(feature = "default_box_extra", since = "1.17.0")]
 impl Default for Box<CStr> {
     fn default() -> Box<CStr> {
@@ -569,7 +583,8 @@ impl CStr {
     #[stable(feature = "rust1", since = "1.0.0")]
     pub unsafe fn from_ptr<'a>(ptr: *const c_char) -> &'a CStr {
         let len = libc::strlen(ptr);
-        mem::transmute(slice::from_raw_parts(ptr, len as usize + 1))
+        let ptr = ptr as *const u8;
+        CStr::from_bytes_with_nul_unchecked(slice::from_raw_parts(ptr, len as usize + 1))
     }
 
     /// Creates a C string wrapper from a byte slice.
@@ -728,6 +743,12 @@ pub fn to_str(&self) -> Result<&str, str::Utf8Error> {
     pub fn to_string_lossy(&self) -> Cow<str> {
         String::from_utf8_lossy(self.to_bytes())
     }
+
+    /// Converts a `Box<CStr>` into a `CString` without copying or allocating.
+    #[unstable(feature = "into_boxed_c_str", issue = "40380")]
+    pub fn into_c_string(self: Box<CStr>) -> CString {
+        unsafe { mem::transmute(self) }
+    }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -922,12 +943,11 @@ fn from_bytes_with_nul_interior() {
     fn into_boxed() {
         let orig: &[u8] = b"Hello, world!\0";
         let cstr = CStr::from_bytes_with_nul(orig).unwrap();
-        let cstring = cstr.to_owned();
-        let box1: Box<CStr> = Box::from(cstr);
-        let box2 = cstring.into_boxed_c_str();
-        assert_eq!(cstr, &*box1);
-        assert_eq!(box1, box2);
-        assert_eq!(&*box2, cstr);
+        let boxed: Box<CStr> = Box::from(cstr);
+        let cstring = cstr.to_owned().into_boxed_c_str().into_c_string();
+        assert_eq!(cstr, &*boxed);
+        assert_eq!(&*boxed, &*cstring);
+        assert_eq!(&*cstring, cstr);
     }
 
     #[test]