search fix to new architecture

common/src/search.rs

@@ -18,6 +18,17 @@ pub const F_DATA_WORD: &str = "data_word";
 pub const F_DATA_NGRAM: &str = "data_ngram";
 pub const F_DATA_EXACT: &str = "data_exact";
 pub const JOURNAL_TABLE_NAME: &str = "general_ledger";
+pub const ARCHIVED_ROW_KEY_PREFIX: &str = "__archive__:";
+pub const SEARCH_INDEX_FORMAT_DIRECTORY: &str = "v2";
+
+/// Root for the current on-disk index format. The format component prevents
+/// an executable with new projection semantics from opening old documents.
+pub fn search_index_root() -> PathBuf {
+    std::env::var_os("TANTIVY_INDEX_DIR")
+        .map(PathBuf::from)
+        .unwrap_or_else(|| PathBuf::from("./tantivy_indexes"))
+        .join(SEARCH_INDEX_FORMAT_DIRECTORY)
+}
 
 pub const TOK_WORD: &str = "kw_word";
 pub const TOK_NGRAM: &str = "kw_ngram";
@@ -33,6 +44,30 @@ pub fn search_row_key(table_name: &str, row_id: i64) -> String {
     format!("{}:{}", table_name, row_id)
 }
 
+/// Returns the unique index key for an immutable archived row version.
+pub fn archived_search_row_key(
+    table_definition_id: i64,
+    row_id: i64,
+    version_number: i64,
+) -> String {
+    format!(
+        "{ARCHIVED_ROW_KEY_PREFIX}{table_definition_id}:{row_id}:{version_number}"
+    )
+}
+
+/// Decodes an archived index key into (table definition, row, version).
+pub fn parse_archived_search_row_key(row_key: &str) -> Option<(i64, i64, i64)> {
+    let encoded = row_key.strip_prefix(ARCHIVED_ROW_KEY_PREFIX)?;
+    let mut parts = encoded.split(':');
+    let table_definition_id = parts.next()?.parse().ok()?;
+    let row_id = parts.next()?.parse().ok()?;
+    let version_number = parts.next()?.parse().ok()?;
+    if parts.next().is_some() {
+        return None;
+    }
+    Some((table_definition_id, row_id, version_number))
+}
+
 /// Normalizes user-entered values for exact-mode terms.
 pub fn normalize_exact(input: &str) -> String {
     let trimmed = input.trim();
@@ -184,6 +219,19 @@ impl SchemaFields {
     }
 }
 
+#[cfg(test)]
+mod tests {
+    use super::{archived_search_row_key, parse_archived_search_row_key};
+
+    #[test]
+    fn archived_row_key_round_trips_stable_identity() {
+        let key = archived_search_row_key(42, 7, 3);
+        assert_eq!(parse_archived_search_row_key(&key), Some((42, 7, 3)));
+        assert_eq!(parse_archived_search_row_key("customers:7"), None);
+        assert_eq!(parse_archived_search_row_key("__archive__:42:7"), None);
+    }
+}
+
 fn get_field(schema: &Schema, name: &str) -> tantivy::Result<Field> {
     schema.get_field(name).map_err(|e| {
         tantivy::TantivyError::SchemaError(format!("schema is missing field '{name}': {e}"))