Add a cton-util filecheck sub-command.

src/tools/rsfilecheck.rs

@@ -0,0 +1,40 @@
+use CommandResult;
+use filecheck::{CheckerBuilder, Checker, NO_VARIABLES};
+use std::fs::File;
+use std::io::{self, Read};
+
+pub fn run(files: Vec<String>, verbose: bool) -> CommandResult {
+    if files.is_empty() {
+        return Err("No check files".to_string());
+    }
+    let checker = try!(read_checkfile(&files[0]));
+    if checker.is_empty() {
+        return Err(format!("{}: no filecheck directives found", files[0]));
+    }
+
+    // Print out the directives under --verbose.
+    if verbose {
+        println!("{}", checker);
+    }
+
+    let mut buffer = String::new();
+    try!(io::stdin().read_to_string(&mut buffer).map_err(|e| format!("stdin: {}", e)));
+
+    if try!(checker.check(&buffer, NO_VARIABLES).map_err(|e| e.to_string())) {
+        Ok(())
+    } else {
+        // TODO: We need to do better than this.
+        Err("Check failed".to_string())
+    }
+}
+
+fn read_checkfile(filename: &str) -> Result<Checker, String> {
+    let mut file = try!(File::open(&filename).map_err(|e| format!("{}: {}", filename, e)));
+    let mut buffer = String::new();
+    try!(file.read_to_string(&mut buffer)
+        .map_err(|e| format!("Couldn't read {}: {}", filename, e)));
+
+    let mut builder = CheckerBuilder::new();
+    try!(builder.text(&buffer).map_err(|e| format!("{}: {}", filename, e)));
+    Ok(builder.finish())
+}