build(rust): vendor googletest crate

third_party/crates/googletest-0.14.3/src/fmt.rs

@@ -0,0 +1,67 @@
+// Copyright 2024 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/// Functions for use only by the procedural macros in this module.
+///
+/// **For internal use only. API stablility is not guaranteed!**
+#[doc(hidden)]
+pub mod internal {
+    use std::fmt::{Debug, Write};
+
+    /// Wrapper to allow for inherent-method specialization based on whether a
+    /// type implements `Debug`.
+    pub struct FormatWrapper<'a, T: ?Sized>(pub &'a T);
+
+    /// Default implementation to render values that implement `Debug`.
+    ///
+    /// Used for autoref specialization to conditionally
+    /// render only values that implement `Debug`. See also
+    /// [`FormatNonDebugFallback`].
+    impl<T: Debug + ?Sized> FormatWrapper<'_, T> {
+        #[track_caller]
+        pub fn __googletest_write_expr_value(&self, output: &mut dyn Write, expr_label: &str) {
+            write!(output, "\n  {} = {:?},", expr_label, self.0)
+                .expect("Formatting to String should never fail");
+        }
+    }
+
+    /// Fallback implementation for rendering values for non-`Debug` types..
+    ///
+    /// Used for inherent-method specialization to conditionally render only
+    /// values that implement `Debug`. See also the specialized inherent impl on
+    /// [`FormatWrapper`] above.
+    pub trait FormatNonDebugFallback {
+        fn __googletest_write_expr_value(&self, output: &mut dyn Write, expr_label: &str);
+    }
+
+    impl<T: ?Sized> FormatNonDebugFallback for FormatWrapper<'_, T> {
+        #[track_caller]
+        fn __googletest_write_expr_value(&self, output: &mut dyn Write, expr_label: &str) {
+            write!(output, "\n  {expr_label} does not implement Debug,")
+                .expect("Formatting to String should never fail");
+        }
+    }
+
+    #[macro_export]
+    macro_rules! __googletest__write_expr_value(
+        ($output:expr, $expr_str:expr, $value:expr $(,)?) => {
+            {
+                use $crate::fmt::internal::FormatNonDebugFallback as _;
+                $crate::fmt::internal::FormatWrapper(&$value)
+                    .__googletest_write_expr_value(&mut $output, $expr_str)
+            }
+        }
+    );
+    pub use __googletest__write_expr_value;
+}