1 files changed, 61 insertions, 0 deletions
diff --git a/third_party/rust/bindgen/deps.rs b/third_party/rust/bindgen/deps.rs
new file mode 100644
index 0000000000..be31f92896
--- /dev/null
+++ b/third_party/rust/bindgen/deps.rs
@@ -0,0 +1,61 @@
+/// Generating build depfiles from parsed bindings.
+use std::{collections::BTreeSet, path::PathBuf};
+
+#[derive(Clone, Debug)]
+pub(crate) struct DepfileSpec {
+    pub output_module: String,
+    pub depfile_path: PathBuf,
+}
+
+impl DepfileSpec {
+    pub fn write(&self, deps: &BTreeSet<Box<str>>) -> std::io::Result<()> {
+        std::fs::write(&self.depfile_path, self.to_string(deps))
+    }
+
+    fn to_string(&self, deps: &BTreeSet<Box<str>>) -> String {
+        // Transforms a string by escaping spaces and backslashes.
+        let escape = |s: &str| s.replace('\\', "\\\\").replace(' ', "\\ ");
+
+        let mut buf = format!("{}:", escape(&self.output_module));
+        for file in deps {
+            buf = format!("{} {}", buf, escape(file));
+        }
+        buf
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn escaping_depfile() {
+        let spec = DepfileSpec {
+            output_module: "Mod Name".to_owned(),
+            depfile_path: PathBuf::new(),
+        };
+
+        let deps: BTreeSet<_> = vec![
+            r"/absolute/path".into(),
+            r"C:\win\absolute\path".into(),
+            r"../relative/path".into(),
+            r"..\win\relative\path".into(),
+            r"../path/with spaces/in/it".into(),
+            r"..\win\path\with spaces\in\it".into(),
+            r"path\with/mixed\separators".into(),
+        ]
+        .into_iter()
+        .collect();
+        assert_eq!(
+            spec.to_string(&deps),
+            "Mod\\ Name: \
+            ../path/with\\ spaces/in/it \
+            ../relative/path \
+            ..\\\\win\\\\path\\\\with\\ spaces\\\\in\\\\it \
+            ..\\\\win\\\\relative\\\\path \
+            /absolute/path \
+            C:\\\\win\\\\absolute\\\\path \
+            path\\\\with/mixed\\\\separators"
+        );
+    }
+}