1 files changed, 76 insertions, 0 deletions
diff --git a/vendor/gix-features/src/cache.rs b/vendor/gix-features/src/cache.rs
new file mode 100644
index 000000000..f7a2cf005
--- /dev/null
+++ b/vendor/gix-features/src/cache.rs
@@ -0,0 +1,76 @@
+#[cfg(feature = "cache-efficiency-debug")]
+mod impl_ {
+    /// A helper to collect useful information about cache efficiency.
+    pub struct Debug {
+        owner: String,
+        hits: usize,
+        puts: usize,
+        misses: usize,
+    }
+
+    impl Debug {
+        /// Create a new instance
+        #[inline]
+        pub fn new(owner: impl Into<String>) -> Self {
+            Debug {
+                owner: owner.into(),
+                hits: 0,
+                puts: 0,
+                misses: 0,
+            }
+        }
+        /// Count cache insertions
+        #[inline]
+        pub fn put(&mut self) {
+            self.puts += 1;
+        }
+        /// Count hits
+        #[inline]
+        pub fn hit(&mut self) {
+            self.hits += 1;
+        }
+        /// Count misses
+        #[inline]
+        pub fn miss(&mut self) {
+            self.misses += 1;
+        }
+    }
+
+    impl Drop for Debug {
+        fn drop(&mut self) {
+            let hits = self.hits;
+            let misses = self.misses;
+            let ratio = hits as f32 / misses as f32;
+            eprintln!(
+                "{}[{:0x}]: {} / {} (hits/misses) = {:.02}%, puts = {}",
+                self.owner,
+                self as *const _ as usize,
+                hits,
+                misses,
+                ratio * 100.0,
+                self.puts
+            );
+        }
+    }
+}
+#[cfg(not(feature = "cache-efficiency-debug"))]
+mod impl_ {
+    /// The disabled, zero size do-nothing equivalent
+    pub struct Debug;
+
+    impl Debug {
+        /// Create a new instance
+        #[inline]
+        pub fn new(_owner: impl Into<String>) -> Self {
+            Debug
+        }
+        /// noop
+        pub fn put(&mut self) {}
+        /// noop
+        pub fn hit(&mut self) {}
+        /// noop
+        pub fn miss(&mut self) {}
+    }
+}
+
+pub use impl_::Debug;