1 files changed, 93 insertions, 0 deletions
diff --git a/app/javascript/mastodon/db/modifier.js b/app/javascript/mastodon/db/modifier.js
new file mode 100644
index 000000000..eb951905a
--- /dev/null
+++ b/app/javascript/mastodon/db/modifier.js
@@ -0,0 +1,93 @@
+import asyncDB from './async';
+
+const limit = 1024;
+
+function put(name, objects, callback) {
+  asyncDB.then(db => {
+    const putTransaction = db.transaction(name, 'readwrite');
+    const putStore = putTransaction.objectStore(name);
+    const putIndex = putStore.index('id');
+
+    objects.forEach(object => {
+      function add() {
+        putStore.add(object);
+      }
+
+      putIndex.getKey(object.id).onsuccess = retrieval => {
+        if (retrieval.target.result) {
+          putStore.delete(retrieval.target.result).onsuccess = add;
+        } else {
+          add();
+        }
+      };
+    });
+
+    putTransaction.oncomplete = () => {
+      const readTransaction = db.transaction(name, 'readonly');
+      const readStore = readTransaction.objectStore(name);
+
+      readStore.count().onsuccess = count => {
+        const excess = count.target.result - limit;
+
+        if (excess > 0) {
+          readStore.getAll(null, excess).onsuccess =
+            retrieval => callback(retrieval.target.result.map(({ id }) => id));
+        }
+      };
+    };
+  });
+}
+
+export function evictAccounts(ids) {
+  asyncDB.then(db => {
+    const transaction = db.transaction(['accounts', 'statuses'], 'readwrite');
+    const accounts = transaction.objectStore('accounts');
+    const accountsIdIndex = accounts.index('id');
+    const accountsMovedIndex = accounts.index('moved');
+    const statuses = transaction.objectStore('statuses');
+    const statusesIndex = statuses.index('account');
+
+    function evict(toEvict) {
+      toEvict.forEach(id => {
+        accountsMovedIndex.getAllKeys(id).onsuccess =
+          ({ target }) => evict(target.result);
+
+        statusesIndex.getAll(id).onsuccess =
+          ({ target }) => evictStatuses(target.result.map(({ id }) => id));
+
+        accountsIdIndex.getKey(id).onsuccess =
+          ({ target }) => target.result && accounts.delete(target.result);
+      });
+    }
+
+    evict(ids);
+  });
+}
+
+export function evictStatus(id) {
+  return evictStatuses([id]);
+}
+
+export function evictStatuses(ids) {
+  asyncDB.then(db => {
+    const store = db.transaction('statuses', 'readwrite').objectStore('statuses');
+    const idIndex = store.index('id');
+    const reblogIndex = store.index('reblog');
+
+    ids.forEach(id => {
+      reblogIndex.getAllKeys(id).onsuccess =
+        ({ target }) => target.result.forEach(reblogKey => store.delete(reblogKey));
+
+      idIndex.getKey(id).onsuccess =
+        ({ target }) => target.result && store.delete(target.result);
+    });
+  });
+}
+
+export function putAccounts(records) {
+  put('accounts', records, evictAccounts);
+}
+
+export function putStatuses(records) {
+  put('statuses', records, evictStatuses);
+}