Squashed 'third_party/autocxx/' content from commit 629e8fa53
git-subtree-dir: third_party/autocxx
git-subtree-split: 629e8fa531a633164c0b52e2a3cab536d4cd0849
Signed-off-by: Brian Silverman <bsilver16384@gmail.com>
Change-Id: I62a03b0049f49adf029e0204639cdb5468dde1a1
diff --git a/engine/src/rust_pretty_printer.rs b/engine/src/rust_pretty_printer.rs
new file mode 100644
index 0000000..9c23cbc
--- /dev/null
+++ b/engine/src/rust_pretty_printer.rs
@@ -0,0 +1,40 @@
+// Copyright 2020 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use proc_macro2::TokenStream;
+use std::io::Write;
+use std::process::{Command, Stdio};
+
+enum Error {
+ Run(std::io::Error),
+ Write(std::io::Error),
+ Utf8(std::string::FromUtf8Error),
+ Wait(std::io::Error),
+}
+
+pub(crate) fn pretty_print(ts: &TokenStream) -> String {
+ reformat_or_else(ts.to_string())
+}
+
+fn reformat_or_else(text: impl std::fmt::Display) -> String {
+ match reformat(&text) {
+ Ok(s) => s,
+ Err(_) => text.to_string(),
+ }
+}
+
+fn reformat(text: impl std::fmt::Display) -> Result<String, Error> {
+ let mut rustfmt = Command::new("rustfmt")
+ .stdin(Stdio::piped())
+ .stdout(Stdio::piped())
+ .spawn()
+ .map_err(Error::Run)?;
+ write!(rustfmt.stdin.take().unwrap(), "{}", text).map_err(Error::Write)?;
+ let output = rustfmt.wait_with_output().map_err(Error::Wait)?;
+ String::from_utf8(output.stdout).map_err(Error::Utf8)
+}