refactor and cleanup [skip ci]

submodules/Postbox/Sources/GlobalMessageIdsTable.swift

@@ -0,0 +1,51 @@
+import Foundation
+
+final class GlobalMessageIdsTable: Table {
+    static func tableSpec(_ id: Int32) -> ValueBoxTable {
+        return ValueBoxTable(id: id, keyType: .int64, compactValuesOnCreation: false)
+    }
+    
+    private let seedConfiguration: SeedConfiguration
+    
+    private let sharedKey = ValueBoxKey(length: 8)
+    private let sharedBuffer = WriteBuffer()
+    
+    init(valueBox: ValueBox, table: ValueBoxTable, seedConfiguration: SeedConfiguration) {
+        self.seedConfiguration = seedConfiguration
+        
+        super.init(valueBox: valueBox, table: table)
+    }
+    
+    private func key(_ id: Int32) -> ValueBoxKey {
+        self.sharedKey.setInt64(0, value: Int64(id))
+        return self.sharedKey
+    }
+    
+    func set(_ globalId: Int32, id: MessageId) {
+        assert(id.namespace == 0)
+        assert(id.peerId.namespace == 0 || id.peerId.namespace == 1)
+        assert(self.seedConfiguration.globalMessageIdsPeerIdNamespaces.contains(GlobalMessageIdsNamespace(peerIdNamespace: id.peerId.namespace, messageIdNamespace: id.namespace)))
+        
+        self.sharedBuffer.reset()
+        var idPeerId: Int64 = id.peerId.toInt64()
+        var idNamespace: Int32 = id.namespace
+        self.sharedBuffer.write(&idPeerId, offset: 0, length: 8)
+        self.sharedBuffer.write(&idNamespace, offset: 0, length: 4)
+        self.valueBox.set(self.table, key: self.key(globalId), value: self.sharedBuffer)
+    }
+    
+    func get(_ globalId: Int32) -> MessageId? {
+        if let value = self.valueBox.get(self.table, key: self.key(globalId)) {
+            var idPeerId: Int64 = 0
+            var idNamespace: Int32 = 0
+            value.read(&idPeerId, offset: 0, length: 8)
+            value.read(&idNamespace, offset: 0, length: 4)
+            return MessageId(peerId: PeerId(idPeerId), namespace: idNamespace, id: globalId)
+        }
+        return nil
+    }
+    
+    func remove(_ globalId: Int32) {
+        self.valueBox.remove(self.table, key: self.key(globalId), secure: false)
+    }
+}