extracting delete role util (not yet used)

src/util/delete_request_role_disambiguation.rs

@@ -0,0 +1,59 @@
+//! This is meant to disambiguate whether the deletion should occur as a user or moderator
+//! for soft-deleted records. All such requests have a similar shape, and this was tested
+//! with a truth table.
+
+#[derive(Copy, Clone, PartialEq, Eq, Debug)]
+pub enum DeleteRole {
+  ErrorDoNotDelete,
+  AsUser,
+  AsMod,
+}
+
+pub fn delete_role_disambiguation(
+  user_is_mod: bool,
+  user_is_author: bool,
+  as_mod_flag: Option<bool>
+) -> DeleteRole {
+  if !user_is_mod && !user_is_author {
+    return DeleteRole::ErrorDoNotDelete;
+  }
+  // NB: Explored this with a truth table.
+  let as_mod_flag_value = as_mod_flag.unwrap_or(false);
+  let delete_as_mod = user_is_mod && !(user_is_author && as_mod_flag.is_some() && !as_mod_flag_value);
+  if delete_as_mod { DeleteRole::AsMod } else { DeleteRole::AsUser }
+}
+
+#[cfg(test)]
+mod tests {
+  use crate::util::delete_request_role_disambiguation::{delete_role_disambiguation, DeleteRole};
+
+  #[test]
+  fn test_delete_as_mod() {
+    // User is neither author nor mod.
+    // Do not delete!
+    assert_eq!(DeleteRole::ErrorDoNotDelete, delete_role_disambiguation(false, false, None));
+    assert_eq!(DeleteRole::ErrorDoNotDelete, delete_role_disambiguation(false, false, Some(false)));
+    assert_eq!(DeleteRole::ErrorDoNotDelete, delete_role_disambiguation(false, false, Some(true)));
+
+    // User is author.
+    // Deleted as a user.
+    assert_eq!(DeleteRole::AsUser, delete_role_disambiguation(false, true, None));
+    assert_eq!(DeleteRole::AsUser, delete_role_disambiguation(false, true, Some(false)));
+    assert_eq!(DeleteRole::AsUser, delete_role_disambiguation(false, true, Some(true)));
+
+    // User is mod.
+    // Deleted as a mod.
+    assert_eq!(DeleteRole::AsMod, delete_role_disambiguation(true, false, None));
+    assert_eq!(DeleteRole::AsMod, delete_role_disambiguation(true, false, Some(false)));
+    assert_eq!(DeleteRole::AsMod, delete_role_disambiguation(true, false, Some(true)));
+
+    // User is mod and author.
+    // Deleting as a user.
+    assert_eq!(DeleteRole::AsUser, delete_role_disambiguation(true, true, Some(false)));
+
+    // User is mod and author.
+    // Deleting as a mod.
+    assert_eq!(DeleteRole::AsMod, delete_role_disambiguation(true, true, None));
+    assert_eq!(DeleteRole::AsMod, delete_role_disambiguation(true, true, Some(true)));
+  }
+}

src/util/mod.rs

@@ -1,5 +1,6 @@
 pub mod anyhow_result;
 pub mod buckets;
+pub mod delete_request_role_disambiguation;
 pub mod email_to_gravatar;
 pub mod encrypted_sort_id;
 pub mod filesystem;