Merge #473

473: Impl `Format` for all `Cow`s r=Urhengulas a=mattico Co-authored-by: Matt Ickstadt <mattico8@gmail.com>
knurling-rs · May 15, 2021 · 0da0e51 · 0da0e51
2 parents f6270ae + 1f86403
commit 0da0e51
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diff --git a/firmware/qemu/src/bin/alloc.out b/firmware/qemu/src/bin/alloc.out
@@ -9,3 +9,7 @@
 0.000008 INFO Vec<Box<i32>>: [-1, 2, 3, 4]
 0.000009 INFO Box<Vec<i32>>: [-1, 2, 3, 4]
 0.000010 INFO String: Hello! I'm a heap-allocated String
+0.000011 INFO Cow<[u32]>: [1, 2, 3, 4]
+0.000012 INFO Cow<Vec<u32>>: [1, 2, 3, 4]
+0.000013 INFO Cow<str>: moo
+0.000014 INFO Cow<String>: moo, but allocated
diff --git a/firmware/qemu/src/bin/alloc.release.out b/firmware/qemu/src/bin/alloc.release.out
@@ -9,3 +9,7 @@
 0.000008 INFO Vec<Box<i32>>: [-1, 2, 3, 4]
 0.000009 INFO Box<Vec<i32>>: [-1, 2, 3, 4]
 0.000010 INFO String: Hello! I'm a heap-allocated String
+0.000011 INFO Cow<[u32]>: [1, 2, 3, 4]
+0.000012 INFO Cow<Vec<u32>>: [1, 2, 3, 4]
+0.000013 INFO Cow<str>: moo
+0.000014 INFO Cow<String>: moo, but allocated
diff --git a/firmware/qemu/src/bin/alloc.rs b/firmware/qemu/src/bin/alloc.rs
@@ -4,6 +4,7 @@
 
 extern crate alloc;
 
+use alloc::borrow::Cow;
 use alloc::boxed::Box;
 use alloc::rc::Rc;
 use alloc::string::String;
@@ -37,6 +38,10 @@ fn main() -> ! {
         "String: {=?}",
         String::from("Hello! I'm a heap-allocated String")
     );
+    defmt::info!("Cow<[u32]>: {=?}", Cow::from(&[1u32, 2, 3, 4][..]));
+    defmt::info!("Cow<Vec<u32>>: {=?}", Cow::from(vec![1u32, 2, 3, 4]));
+    defmt::info!("Cow<str>: {=?}", Cow::from("moo"));
+    defmt::info!("Cow<String>: {=?}", String::from("moo, but allocated"));
 
     loop {
         debug::exit(debug::EXIT_SUCCESS)

diff --git a/src/impls.rs b/src/impls.rs
@@ -447,6 +447,22 @@ mod if_alloc {
             self.as_str().format(f)
         }
     }
+
+    impl<'a, T> Format for alloc::borrow::Cow<'a, [T]>
+    where
+        T: 'a + Format,
+        [T]: alloc::borrow::ToOwned<Owned = alloc::vec::Vec<T>>,
+    {
+        fn format(&self, f: Formatter) {
+            self.as_ref().format(f)
+        }
+    }
+
+    impl<'a> Format for alloc::borrow::Cow<'a, str> {
+        fn format(&self, f: Formatter) {
+            self.as_ref().format(f)
+        }
+    }
 }
 
 impl Format for core::convert::Infallible {