refactor and cleanup [skip ci]

submodules/Postbox/Sources/AccountManagerSharedDataTable.swift

@@ -0,0 +1,31 @@
+import Foundation
+
+final class AccountManagerSharedDataTable: Table {
+    static func tableSpec(_ id: Int32) -> ValueBoxTable {
+        return ValueBoxTable(id: id, keyType: .binary, compactValuesOnCreation: false)
+    }
+    
+    func get(key: ValueBoxKey) -> PreferencesEntry? {
+        if let value = self.valueBox.get(self.table, key: key), let object = PostboxDecoder(buffer: value).decodeRootObject() as? PreferencesEntry {
+            return object
+        } else {
+            return nil
+        }
+    }
+    
+    func set(key: ValueBoxKey, value: PreferencesEntry?, updatedKeys: inout Set<ValueBoxKey>) {
+        if let value = value {
+            if let current = self.get(key: key), current.isEqual(to: value) {
+                return
+            }
+            let encoder = PostboxEncoder()
+            encoder.encodeRootObject(value)
+            self.valueBox.set(self.table, key: key, value: encoder.makeReadBufferAndReset())
+            updatedKeys.insert(key)
+        } else if self.get(key: key) != nil {
+            self.valueBox.remove(self.table, key: key, secure: false)
+            updatedKeys.insert(key)
+        }
+    }
+}
+