1 files changed, 46 insertions, 0 deletions
diff --git a/tools/record-finalized-flags/src/flag_report.rs b/tools/record-finalized-flags/src/flag_report.rs
new file mode 100644
index 0000000000..ab2643231e
--- /dev/null
+++ b/tools/record-finalized-flags/src/flag_report.rs
@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 2025 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+use anyhow::Result;
+use std::{collections::HashSet, io::Read};
+
+use crate::FlagId;
+
+/// Read a flag report generated by `metalava flag-report` representing all flags known by the
+/// build, and filter out the flags in the report that metalava has marked as finalized.
+pub(crate) fn read_and_filter_flag_report<R: Read>(mut reader: R) -> Result<HashSet<FlagId>> {
+    let mut contents = String::new();
+    reader.read_to_string(&mut contents)?;
+    let iter =
+        contents.lines().filter(|s| s.ends_with(",finalized") || s.ends_with(",kept")).map(|s| {
+            let (flag, _) =
+                s.split_once(",").expect("previous filter guarantees at least one comma");
+            flag.to_owned()
+        });
+    Ok(HashSet::from_iter(iter))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test() {
+        let input = include_bytes!("../tests/flag-report.csv");
+        let flags = read_and_filter_flag_report(&input[..]).unwrap();
+        assert_eq!(flags, HashSet::from_iter(["com.foo".to_string(), "com.baz".to_string(),]));
+    }
+}