multiboot2: Replace ptr_metadata feature with slice_from_raw_parts

The former one would probably be cleaner, but it's not yet stable.

Author: YtvwlD

multiboot2/src/boot_loader_name.rs

@@ -72,6 +72,8 @@ impl StructAsBytes for BootLoaderNameTag {
 
 #[cfg(test)]
 mod tests {
+    use core::ptr::slice_from_raw_parts;
+
     use crate::{TagType, boot_loader_name::METADATA_SIZE};
 
     const MSG: &str = "hello";
@@ -98,8 +100,8 @@ mod tests {
     fn test_parse_str() {
         let tag = get_bytes();
         let tag = unsafe {
-            let (ptr, _) = tag.as_ptr().to_raw_parts();
-            (core::ptr::from_raw_parts(
+            let ptr = tag.as_ptr() as *const ();
+            (slice_from_raw_parts(
                 ptr, tag.len() - METADATA_SIZE
             ) as *const super::BootLoaderNameTag)
                 .as_ref()

multiboot2/src/builder/mod.rs

@@ -9,6 +9,7 @@ pub use information::Multiboot2InformationBuilder;
 use core::alloc::Layout;
 use core::convert::TryInto;
 use core::mem::size_of;
+use core::ptr::slice_from_raw_parts_mut;
 use alloc::alloc::alloc;
 use alloc::boxed::Box;
 
@@ -36,9 +37,9 @@ pub(super) fn boxed_dst_tag(typ: TagType, content: &[u8]) -> Box<Tag> {
             content_ptr.add(idx).write(*val);
         }
         Box::from_raw(
-            core::ptr::from_raw_parts_mut(
-                ptr as *mut (), content.len()
-            )
+            slice_from_raw_parts_mut(
+                ptr as *mut usize, content.len()
+            ) as *mut Tag
         )
     }
 }

multiboot2/src/command_line.rs

@@ -70,6 +70,8 @@ impl StructAsBytes for CommandLineTag {
 
 #[cfg(test)]
 mod tests {
+    use core::ptr::slice_from_raw_parts;
+
     use crate::{TagType, command_line::METADATA_SIZE};
 
     const MSG: &str = "hello";
@@ -96,8 +98,8 @@ mod tests {
     fn test_parse_str() {
         let tag = get_bytes();
         let tag = unsafe {
-            let (ptr, _) = tag.as_ptr().to_raw_parts();
-            (core::ptr::from_raw_parts(
+            let ptr = tag.as_ptr() as *const ();
+            (slice_from_raw_parts(
                 ptr, tag.len() - METADATA_SIZE
             ) as *const super::CommandLineTag)
                 .as_ref()

multiboot2/src/lib.rs

@@ -34,8 +34,6 @@
 //! ## MSRV
 //! The MSRV is 1.52.1 stable.
 
-#![feature(ptr_metadata)]
-
 #[cfg(feature = "builder")]
 extern crate alloc;
 
@@ -44,7 +42,7 @@ extern crate alloc;
 #[cfg(test)]
 extern crate std;
 
-use core::{fmt, convert::TryInto};
+use core::{fmt, convert::TryInto, ptr::slice_from_raw_parts};
 
 pub use boot_loader_name::BootLoaderNameTag;
 #[cfg(feature = "builder")]
@@ -351,7 +349,7 @@ impl BootInformation {
             (next_ptr as *const u32).add(1).read()
         }.try_into().unwrap();
         TagIter::new(
-            core::ptr::from_raw_parts(next_ptr, size - METADATA_SIZE)
+            slice_from_raw_parts(next_ptr, size - METADATA_SIZE) as *mut Tag
         )
     }
 }

multiboot2/src/module.rs

@@ -7,6 +7,7 @@ use crate::builder::traits::StructAsBytes;
 use core::convert::TryInto;
 use core::fmt::{Debug, Formatter};
 use core::mem;
+use core::ptr::slice_from_raw_parts;
 use core::str::Utf8Error;
 
 #[cfg(feature = "builder")]
@@ -113,8 +114,8 @@ impl<'a> Iterator for ModuleIter<'a> {
         self.iter
             .find(|x| x.typ == TagType::Module)
             .map(|tag| unsafe {
-                let (ptr, _) = (tag as *const Tag).to_raw_parts();
-                &*(core::ptr::from_raw_parts(
+                let ptr = tag as *const Tag as *const ();
+                &*(slice_from_raw_parts(
                     ptr, tag.size as usize - METADATA_SIZE,
                 ) as *const ModuleTag)
              })
@@ -133,6 +134,8 @@ impl<'a> Debug for ModuleIter<'a> {
 
 #[cfg(test)]
 mod tests {
+    use core::ptr::slice_from_raw_parts;
+
     use crate::{TagType, module::METADATA_SIZE};
 
     const MSG: &str = "hello";
@@ -162,9 +165,9 @@ mod tests {
     fn test_parse_str() {
         let tag = get_bytes();
         let tag = unsafe {
-            let (ptr, _) = tag.as_ptr().to_raw_parts();
+            let ptr = tag.as_ptr() as *const ();
             &*(
-                core::ptr::from_raw_parts(ptr, tag.len() - METADATA_SIZE)
+                slice_from_raw_parts(ptr, tag.len() - METADATA_SIZE)
                 as *const super::ModuleTag
             )
         };

multiboot2/src/tag_type.rs

@@ -7,6 +7,7 @@ use core::fmt::{Debug, Formatter};
 use core::hash::Hash;
 use core::marker::PhantomData;
 use core::mem::size_of;
+use core::ptr::slice_from_raw_parts;
 
 /// Possible types of a Tag in the Multiboot2 Information Structure (MBI), therefore the value
 /// of the the `typ` property. The names and values are taken from the example C code
@@ -179,15 +180,15 @@ impl<'a> Iterator for TagIter<'a> {
             } => None, // end tag
             tag => {
                 // go to next tag
-                let (tag_addr, _) = self.current.to_raw_parts();
+                let tag_addr = self.current as *const ();
                 let mut tag_addr = tag_addr as usize;
                 tag_addr += ((tag.size + 7) & !7) as usize; //align at 8 byte
                 let size: usize = unsafe {
                     (tag_addr as *const u32).add(1).read()
                 }.try_into().unwrap();
-                self.current = core::ptr::from_raw_parts(
+                self.current = slice_from_raw_parts(
                     tag_addr as *const (), size - METADATA_SIZE,
-                );
+                ) as *const Tag;
 
                 Some(tag)
             }