Now works on beta/stable

Until rust-lang/rust#35729 stabilizes, we directly import and implement
the `SliceIndex` trait, which lets us work correctly on stable!

Author: jonhoo

.travis.yml

@@ -19,6 +19,8 @@ env:
 before_install: . vendor/bindgen/ci/before_install.sh
 rust:
   - nightly
+  - beta
+  - stable
 cache: cargo
 matrix:
   allow_failures:

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ibverbs"
-version = "0.2.4"
+version = "0.3.0"
 
 description = "Bindings for RDMA ibverbs through rdma-core"
 readme = "README.md"

src/lib.rs

@@ -61,7 +61,6 @@
 //! [1]: http://www.rdmamojo.com/2012/05/18/libibverbs/
 
 #![deny(missing_docs)]
-#![feature(slice_get_slice)]
 
 use std::marker::PhantomData;
 use std::ptr;
@@ -96,6 +95,10 @@ pub use ffi::IBV_ACCESS_REMOTE_READ;
 /// Enable Remote Atomic Operation Access (if supported).
 pub use ffi::IBV_ACCESS_REMOTE_ATOMIC;
 
+/// Because `std::slice::SliceIndex` is still unstable, we follow @alexcrichton's suggestion in
+/// https://github.com/rust-lang/rust/issues/35729 and implement it ourselves.
+mod sliceindex;
+
 /// Get list of available RDMA devices.
 ///
 /// # Errors
@@ -1082,9 +1085,9 @@ impl<'res> QueuePair<'res> {
                                   range: R,
                                   wr_id: u64)
                                   -> io::Result<()>
-        where R: std::slice::SliceIndex<[T], Output = [T]>
+        where R: sliceindex::SliceIndex<[T], Output = [T]>
     {
-        let range = &mr[range];
+        let range = range.index(&mr);
         let mut sge = ffi::ibv_sge {
             addr: range.as_ptr() as u64,
             length: (mem::size_of::<T>() * range.len()) as u32,
@@ -1165,9 +1168,9 @@ impl<'res> QueuePair<'res> {
                                      range: R,
                                      wr_id: u64)
                                      -> io::Result<()>
-        where R: std::slice::SliceIndex<[T], Output = [T]>
+        where R: sliceindex::SliceIndex<[T], Output = [T]>
     {
-        let range = &mr[range];
+        let range = range.index(&mr);
         let mut sge = ffi::ibv_sge {
             addr: range.as_ptr() as u64,
             length: (mem::size_of::<T>() * range.len()) as u32,

src/sliceindex.rs

@@ -0,0 +1,143 @@
+use std::ops;
+
+pub trait SliceIndex<T: ?Sized> {
+    /// The output type returned by methods.
+    type Output: ?Sized;
+
+    /// Returns a shared reference to the output at this location, without
+    /// performing any bounds checking.
+    unsafe fn get_unchecked(self, slice: &T) -> &Self::Output;
+
+    /// Returns a shared reference to the output at this location, panicking
+    /// if out of bounds.
+    fn index(self, slice: &T) -> &Self::Output;
+}
+
+impl<T> SliceIndex<[T]> for usize {
+    type Output = T;
+
+    #[inline]
+    unsafe fn get_unchecked(self, slice: &[T]) -> &T {
+        &*slice.as_ptr().offset(self as isize)
+    }
+
+    #[inline]
+    fn index(self, slice: &[T]) -> &T {
+        // NB: use intrinsic indexing
+        &(*slice)[self]
+    }
+}
+
+#[inline(never)]
+#[cold]
+fn slice_index_len_fail(index: usize, len: usize) -> ! {
+    panic!("index {} out of range for slice of length {}", index, len);
+}
+
+#[inline(never)]
+#[cold]
+fn slice_index_order_fail(index: usize, end: usize) -> ! {
+    panic!("slice index starts at {} but ends at {}", index, end);
+}
+
+impl<T> SliceIndex<[T]> for ops::Range<usize> {
+    type Output = [T];
+
+    #[inline]
+    unsafe fn get_unchecked(self, slice: &[T]) -> &[T] {
+        use std::slice::from_raw_parts;
+        from_raw_parts(slice.as_ptr().offset(self.start as isize),
+                       self.end - self.start)
+    }
+
+    #[inline]
+    fn index(self, slice: &[T]) -> &[T] {
+        if self.start > self.end {
+            slice_index_order_fail(self.start, self.end);
+        } else if self.end > slice.len() {
+            slice_index_len_fail(self.end, slice.len());
+        }
+        unsafe { self.get_unchecked(slice) }
+    }
+}
+
+impl<T> SliceIndex<[T]> for ops::RangeTo<usize> {
+    type Output = [T];
+
+    #[inline]
+    unsafe fn get_unchecked(self, slice: &[T]) -> &[T] {
+        (0..self.end).get_unchecked(slice)
+    }
+
+    #[inline]
+    fn index(self, slice: &[T]) -> &[T] {
+        (0..self.end).index(slice)
+    }
+}
+
+impl<T> SliceIndex<[T]> for ops::RangeFrom<usize> {
+    type Output = [T];
+
+    #[inline]
+    unsafe fn get_unchecked(self, slice: &[T]) -> &[T] {
+        (self.start..slice.len()).get_unchecked(slice)
+    }
+
+    #[inline]
+    fn index(self, slice: &[T]) -> &[T] {
+        (self.start..slice.len()).index(slice)
+    }
+}
+
+impl<T> SliceIndex<[T]> for ops::RangeFull {
+    type Output = [T];
+
+    #[inline]
+    unsafe fn get_unchecked(self, slice: &[T]) -> &[T] {
+        slice
+    }
+
+    #[inline]
+    fn index(self, slice: &[T]) -> &[T] {
+        slice
+    }
+}
+
+// nightly only:
+//
+// impl<T> SliceIndex<[T]> for ops::RangeInclusive<usize> {
+//     type Output = [T];
+//
+//     #[inline]
+//     unsafe fn get_unchecked(self, slice: &[T]) -> &[T] {
+//         match self {
+//             ops::RangeInclusive::Empty { .. } => &[],
+//             ops::RangeInclusive::NonEmpty { start, end } => (start..end + 1).get_unchecked(slice),
+//         }
+//     }
+//
+//     #[inline]
+//     fn index(self, slice: &[T]) -> &[T] {
+//         match self {
+//             ops::RangeInclusive::Empty { .. } => &[],
+//             ops::RangeInclusive::NonEmpty { end, .. } if end == usize::max_value() => {
+//                 panic!("attempted to index slice up to maximum usize");
+//             }
+//             ops::RangeInclusive::NonEmpty { start, end } => (start..end + 1).index(slice),
+//         }
+//     }
+// }
+//
+// impl<T> SliceIndex<[T]> for ops::RangeToInclusive<usize> {
+//     type Output = [T];
+//
+//     #[inline]
+//     unsafe fn get_unchecked(self, slice: &[T]) -> &[T] {
+//         (0...self.end).get_unchecked(slice)
+//     }
+//
+//     #[inline]
+//     fn index(self, slice: &[T]) -> &[T] {
+//         (0...self.end).index(slice)
+//     }
+// }