access: signatures required

"signatures": "required": a change counts only once a signature by its
committer vouches for it, and waits until then; every node then signs
every change it makes.

Auth plan M6.

1 files changed, 21 insertions, 7 deletions

diff --git a/src/access/policy.rs b/src/access/policy.rs
index 7ddef0e..f8ccfc2 100644
--- a/src/access/policy.rs
+++ b/src/access/policy.rs
@@ -4,7 +4,9 @@
 //! by a user who may write protocol data, as any of it.
 //!
 //! `{"version": 1, "signatures": "optional"}`: rules enforced; a change is its claimed
-//! committer's whether or not a signature proves it (`document::signatures`). A policy
+//! committer's whether or not a signature proves it (`document::signatures`).
+//! `"required"`: a change is applied once a signature by its committer vouches for it,
+//! and waits until then; every node signs every change it makes. A policy
 //! this node doesn't know (another version, or a setting it lacks) stops it from taking
 //! writes through the API, and it receives without judging: it can't judge as the
 //! others do, so it writes nothing they might refuse, until it is upgraded.
@@ -26,15 +28,21 @@ pub(crate) fn path() -> Vec<String> {
 pub(crate) enum Policy {
     /// None: changes aren't judged.
     Open,
-    /// Rules by path enforced.
-    Enforced,
+    /// Rules by path enforced; with signatures `required`, only on changes a signature
+    /// proves.
+    Enforced { required: bool },
     /// One this node doesn't know, and why.
     Unknown(String),
 }
 
 impl Policy {
     pub(crate) fn enforced(&self) -> bool {
-        matches!(self, Policy::Enforced)
+        matches!(self, Policy::Enforced { .. })
+    }
+
+    /// Whether changes need a signature (`signatures: "required"`).
+    pub(crate) fn required(&self) -> bool {
+        matches!(self, Policy::Enforced { required: true })
     }
 }
 
@@ -55,7 +63,8 @@ pub(crate) fn of(doc: &impl ReadDoc) -> Policy {
         ));
     }
     match value.get("signatures").and_then(JsonValue::as_str) {
-        None | Some("optional") => Policy::Enforced,
+        None | Some("optional") => Policy::Enforced { required: false },
+        Some("required") => Policy::Enforced { required: true },
         Some(other) => Policy::Unknown(format!("signatures {other:?}")),
     }
 }
@@ -78,10 +87,15 @@ mod tests {
     #[test]
     fn what_the_policy_says() {
         assert_eq!(of(&Document::new()), Policy::Open);
-        assert_eq!(with(json!({"version": 1})), Policy::Enforced);
+        let optional = Policy::Enforced { required: false };
+        assert_eq!(with(json!({"version": 1})), optional);
         assert_eq!(
             with(json!({"version": 1, "signatures": "optional"})),
-            Policy::Enforced
+            optional
+        );
+        assert_eq!(
+            with(json!({"version": 1, "signatures": "required"})),
+            Policy::Enforced { required: true }
         );
         assert!(matches!(with(json!({"version": 2})), Policy::Unknown(_)));
         assert!(matches!(