refactor and cleanup [skip ci]

submodules/Postbox/Sources/DeviceContactImportInfoTable.swift

@@ -0,0 +1,46 @@
+import Foundation
+
+final class DeviceContactImportInfoTable: Table {
+    static func tableSpec(_ id: Int32) -> ValueBoxTable {
+        return ValueBoxTable(id: id, keyType: .binary, compactValuesOnCreation: true)
+    }
+    
+    func get(_ identifier: ValueBoxKey) -> PostboxCoding? {
+        if let value = self.valueBox.get(self.table, key: identifier), let object = PostboxDecoder(buffer: value).decodeRootObject() {
+            return object
+        } else {
+            return nil
+        }
+    }
+    
+    func set(_ identifier: ValueBoxKey, value: PostboxCoding?) {
+        if let value = value {
+            let encoder = PostboxEncoder()
+            encoder.encodeRootObject(value)
+            withExtendedLifetime(encoder, {
+                self.valueBox.set(self.table, key: identifier, value: encoder.readBufferNoCopy())
+            })
+        } else {
+            self.valueBox.remove(self.table, key: identifier, secure: false)
+        }
+    }
+    
+    func getIdentifiers() -> [ValueBoxKey] {
+        var result: [ValueBoxKey] = []
+        self.valueBox.scan(self.table, keys: { key in
+            result.append(key)
+            return true
+        })
+        return result
+    }
+    
+    func enumerateDeviceContactImportInfoItems(_ f: (ValueBoxKey, PostboxCoding) -> Bool) {
+        self.valueBox.scan(self.table, values: { key, value in
+            if let object = PostboxDecoder(buffer: value).decodeRootObject() {
+                return f(key, object)
+            } else {
+                return true
+            }
+        })
+    }
+}