access: the user registry

_continuum/users/<name>: one entry per user, with capabilities by path
(read, write) granted by whom and when, and a disabled flag. Read
leniently: a damaged entry gives less, never more. Protocol data stays
apart: a capability outside _continuum never covers it.

Auth plan M1.

1 files changed, 5 insertions, 0 deletions

diff --git a/src/document/store.rs b/src/document/store.rs
index f18f2fa..db5ecbc 100644
--- a/src/document/store.rs
+++ b/src/document/store.rs
@@ -650,6 +650,11 @@ fn summary(
     Ok(JsonValue::Object(out))
 }
 
+/// Whether `path` holds a map (one, or concurrent ones merged).
+pub(crate) fn is_map(doc: &impl ReadDoc, path: &[String]) -> bool {
+    matches!(resolve_through(doc, path), Ok(Some(Resolved::Maps(_))))
+}
+
 /// Keys of the merged map at `path`; empty if it doesn't exist or isn't a map.
 pub(crate) fn keys_at(doc: &impl ReadDoc, path: &[String]) -> Result<Vec<String>, StoreError> {
     Ok(match resolve_through(doc, path)? {