1 files changed, 74 insertions, 0 deletions
diff --git a/src/marmot-store.js b/src/marmot-store.js
new file mode 100644
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+++ b/src/marmot-store.js
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+// Where White Noise (Marmot) state lives: IndexedDB, one record per group.
+//
+// MLS state is the opposite of everything else this wallet keeps: it cannot
+// be refetched or rederived (a lost ratchet is a lost group), it holds
+// Uint8Arrays by the dozen (structured clone stores them as-is, JSON would
+// triple them), and it is DEVICE state — two devices replaying one leaf's
+// ratchet would reuse keys. So it stays out of the localStorage feature
+// state and out of the cross-device sync, in a store of its own.
+//
+// Records are scoped by `scope` (wallet cache key + nostr identity), so two
+// wallets or two identities on one browser never read each other's groups.
+
+const DB = 'coinos-marmot';
+const STORE = 'kv';
+
+let dbP = null;
+function db() {
+  if (!dbP)
+    dbP = new Promise((resolve, reject) => {
+      if (typeof indexedDB === 'undefined') return reject(new Error('IndexedDB unavailable'));
+      const req = indexedDB.open(DB, 1);
+      req.onupgradeneeded = () => {
+        if (!req.result.objectStoreNames.contains(STORE)) req.result.createObjectStore(STORE);
+      };
+      req.onsuccess = () => {
+        // another tab upgrading or deleting the database must not be blocked
+        req.result.onversionchange = () => { req.result.close(); dbP = null; };
+        resolve(req.result);
+      };
+      req.onerror = () => { dbP = null; reject(req.error); };
+    });
+  return dbP;
+}
+
+async function tx(mode, fn) {
+  const d = await db();
+  return new Promise((resolve, reject) => {
+    const t = d.transaction(STORE, mode);
+    let out;
+    try { out = fn(t.objectStore(STORE)); } catch (e) { reject(e); return; }
+    t.oncomplete = () => resolve(out && 'result' in out ? out.result : out);
+    t.onerror = () => reject(t.error);
+    t.onabort = () => reject(t.error);
+  });
+}
+
+export function marmotStore(scope) {
+  const pre = scope + '|';
+  const range = () => IDBKeyRange.bound(pre, pre + '');
+  return {
+    // every record of this scope: Map(name -> value)
+    async all() {
+      const out = new Map();
+      await tx('readonly', (s) => {
+        const cur = s.openCursor(range());
+        cur.onsuccess = () => {
+          const c = cur.result;
+          if (!c) return;
+          out.set(String(c.key).slice(pre.length), c.value);
+          c.continue();
+        };
+      });
+      return out;
+    },
+    put: (name, value) => tx('readwrite', (s) => { s.put(value, pre + name); }),
+    del: (name) => tx('readwrite', (s) => { s.delete(pre + name); }),
+    wipe: () => tx('readwrite', (s) => { s.delete(range()); }),
+  };
+}
+
+// Drop every scope under a wallet (the account-wipe hook).
+export function wipeMarmot(walletKey) {
+  return tx('readwrite', (s) => { s.delete(IDBKeyRange.bound(walletKey, walletKey + '')); }).catch(() => {});
+}