1 files changed, 51 insertions, 0 deletions
diff --git a/vendor/semver/src/backport.rs b/vendor/semver/src/backport.rs
new file mode 100644
index 000000000..c7751b29f
--- /dev/null
+++ b/vendor/semver/src/backport.rs
@@ -0,0 +1,51 @@
+#[cfg(no_str_strip_prefix)] // rustc <1.45
+pub(crate) trait StripPrefixExt {
+    fn strip_prefix(&self, ch: char) -> Option<&str>;
+}
+
+#[cfg(no_str_strip_prefix)]
+impl StripPrefixExt for str {
+    fn strip_prefix(&self, ch: char) -> Option<&str> {
+        if self.starts_with(ch) {
+            Some(&self[ch.len_utf8()..])
+        } else {
+            None
+        }
+    }
+}
+
+pub(crate) use crate::alloc::vec::Vec;
+
+#[cfg(no_alloc_crate)] // rustc <1.36
+pub(crate) mod alloc {
+    pub use std::vec;
+
+    pub mod alloc {
+        use std::mem;
+
+        pub struct Layout {
+            size: usize,
+        }
+
+        impl Layout {
+            pub unsafe fn from_size_align_unchecked(size: usize, align: usize) -> Self {
+                assert_eq!(align, 2);
+                Layout { size }
+            }
+        }
+
+        pub unsafe fn alloc(layout: Layout) -> *mut u8 {
+            let len_u16 = (layout.size + 1) / 2;
+            let mut vec = Vec::new();
+            vec.reserve_exact(len_u16);
+            let ptr: *mut u16 = vec.as_mut_ptr();
+            mem::forget(vec);
+            ptr as *mut u8
+        }
+
+        pub unsafe fn dealloc(ptr: *mut u8, layout: Layout) {
+            let len_u16 = (layout.size + 1) / 2;
+            unsafe { Vec::from_raw_parts(ptr as *mut u16, 0, len_u16) };
+        }
+    }
+}