build.rs

   1 use std::{
   2     env, fs,
   3     io::{self, Read, Write},
   4     path::Path,
   5     process::{Child, Command, Stdio},
   6     thread,
   7 };
   8 use vector_math_build_helpers::make_context_types;
   9
  10 fn format_source(source: String) -> String {
  11     match try_format_source(&source) {
  12         Ok(v) => v,
  13         Err(e) => {
  14             eprintln!("rustfmt failed: {}", e);
  15             source
  16         }
  17     }
  18 }
  19
  20 fn try_format_source(source: &str) -> io::Result<String> {
  21     let mut command = Command::new("rustfmt")
  22         .stdin(Stdio::piped())
  23         .stdout(Stdio::piped())
  24         .spawn()?;
  25     let stdin = command.stdin.take().unwrap();
  26     let reader_thread = thread::spawn(move || -> io::Result<(String, Child)> {
  27         let mut output = String::new();
  28         command.stdout.take().unwrap().read_to_string(&mut output)?;
  29         Ok((output, command))
  30     });
  31     let write_result = { stdin }.write_all(source.as_bytes());
  32     let join_result = reader_thread.join().unwrap();
  33     write_result?;
  34     let (output, mut command) = join_result?;
  35     let exit_status = command.wait()?;
  36     if exit_status.success() {
  37         Ok(output)
  38     } else {
  39         Err(io::Error::new(
  40             io::ErrorKind::Other,
  41             format!("exited with status {}", exit_status),
  42         ))
  43     }
  44 }
  45
  46 fn main() {
  47     fs::write(
  48         Path::new(&env::var_os("OUT_DIR").unwrap()).join("context_trait.rs"),
  49         format_source(make_context_types().to_string()),
  50     )
  51     .unwrap();
  52 }