1 files changed, 97 insertions, 0 deletions
diff --git a/vendor/kstring/src/backend.rs b/vendor/kstring/src/backend.rs
new file mode 100644
index 000000000..3827082f1
--- /dev/null
+++ b/vendor/kstring/src/backend.rs
@@ -0,0 +1,97 @@
+#[cfg(feature = "arc")]
+pub(crate) type DefaultStr = crate::backend::ArcStr;
+#[cfg(not(feature = "arc"))]
+pub(crate) type DefaultStr = crate::backend::BoxedStr;
+
+/// Fast allocations, O(n) clones
+pub type BoxedStr = Box<str>;
+static_assertions::assert_eq_size!(DefaultStr, BoxedStr);
+
+/// Cross-thread, O(1) clones
+pub type ArcStr = std::sync::Arc<str>;
+static_assertions::assert_eq_size!(DefaultStr, ArcStr);
+
+/// O(1) clones
+pub type RcStr = std::rc::Rc<str>;
+static_assertions::assert_eq_size!(DefaultStr, RcStr);
+
+/// Abstract over different type of heap-allocated strings
+pub trait HeapStr: std::fmt::Debug + Clone + private::Sealed {
+    fn from_str(other: &str) -> Self;
+    fn from_string(other: String) -> Self;
+    fn from_boxed_str(other: BoxedStr) -> Self;
+    fn as_str(&self) -> &str;
+}
+
+impl HeapStr for BoxedStr {
+    #[inline]
+    fn from_str(other: &str) -> Self {
+        other.into()
+    }
+
+    #[inline]
+    fn from_string(other: String) -> Self {
+        other.into_boxed_str()
+    }
+
+    #[inline]
+    fn from_boxed_str(other: BoxedStr) -> Self {
+        other
+    }
+
+    #[inline]
+    fn as_str(&self) -> &str {
+        self
+    }
+}
+
+impl HeapStr for ArcStr {
+    #[inline]
+    fn from_str(other: &str) -> Self {
+        other.into()
+    }
+
+    #[inline]
+    fn from_string(other: String) -> Self {
+        other.into_boxed_str().into()
+    }
+
+    #[inline]
+    fn from_boxed_str(other: BoxedStr) -> Self {
+        other.into()
+    }
+
+    #[inline]
+    fn as_str(&self) -> &str {
+        self
+    }
+}
+
+impl HeapStr for RcStr {
+    #[inline]
+    fn from_str(other: &str) -> Self {
+        other.into()
+    }
+
+    #[inline]
+    fn from_string(other: String) -> Self {
+        other.into_boxed_str().into()
+    }
+
+    #[inline]
+    fn from_boxed_str(other: BoxedStr) -> Self {
+        other.into()
+    }
+
+    #[inline]
+    fn as_str(&self) -> &str {
+        self
+    }
+}
+
+pub(crate) mod private {
+    pub trait Sealed {}
+    impl Sealed for super::BoxedStr {}
+    impl Sealed for super::ArcStr {}
+    impl Sealed for super::RcStr {}
+}