1 files changed, 52 insertions, 0 deletions
diff --git a/src/tools/rustfmt/src/ignore_path.rs b/src/tools/rustfmt/src/ignore_path.rs
new file mode 100644
index 000000000..d95594949
--- /dev/null
+++ b/src/tools/rustfmt/src/ignore_path.rs
@@ -0,0 +1,52 @@
+use ignore::{self, gitignore};
+
+use crate::config::{FileName, IgnoreList};
+
+pub(crate) struct IgnorePathSet {
+    ignore_set: gitignore::Gitignore,
+}
+
+impl IgnorePathSet {
+    pub(crate) fn from_ignore_list(ignore_list: &IgnoreList) -> Result<Self, ignore::Error> {
+        let mut ignore_builder = gitignore::GitignoreBuilder::new(ignore_list.rustfmt_toml_path());
+
+        for ignore_path in ignore_list {
+            ignore_builder.add_line(None, ignore_path.to_str().unwrap())?;
+        }
+
+        Ok(IgnorePathSet {
+            ignore_set: ignore_builder.build()?,
+        })
+    }
+
+    pub(crate) fn is_match(&self, file_name: &FileName) -> bool {
+        match file_name {
+            FileName::Stdin => false,
+            FileName::Real(p) => self
+                .ignore_set
+                .matched_path_or_any_parents(p, false)
+                .is_ignore(),
+        }
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use rustfmt_config_proc_macro::nightly_only_test;
+
+    #[nightly_only_test]
+    #[test]
+    fn test_ignore_path_set() {
+        use crate::config::{Config, FileName};
+        use crate::ignore_path::IgnorePathSet;
+        use std::path::{Path, PathBuf};
+
+        let config =
+            Config::from_toml(r#"ignore = ["foo.rs", "bar_dir/*"]"#, Path::new("")).unwrap();
+        let ignore_path_set = IgnorePathSet::from_ignore_list(&config.ignore()).unwrap();
+
+        assert!(ignore_path_set.is_match(&FileName::Real(PathBuf::from("src/foo.rs"))));
+        assert!(ignore_path_set.is_match(&FileName::Real(PathBuf::from("bar_dir/baz.rs"))));
+        assert!(!ignore_path_set.is_match(&FileName::Real(PathBuf::from("src/bar.rs"))));
+    }
+}