Signal-iOS/SignalServiceKit/Storage/Database/SDSDeserialization.swift
2024-03-27 12:22:52 -05:00

118 lines
4.0 KiB
Swift

//
// Copyright 2019 Signal Messenger, LLC
// SPDX-License-Identifier: AGPL-3.0-only
//
import Foundation
import GRDB
import SignalCoreKit
// Sentinel protocol used to convey that a Codable type should be encoded/decoded to database storage
// using Swift.Codable instead of NS(Secure)Coding.
public protocol SDSSwiftSerializable: Codable {}
extension Array: SDSSwiftSerializable where Element: SDSSwiftSerializable {}
extension Dictionary: SDSSwiftSerializable where Key: SDSSwiftSerializable, Value: SDSSwiftSerializable {}
extension Set: SDSSwiftSerializable where Element: SDSSwiftSerializable {}
extension Optional: SDSSwiftSerializable where Wrapped: SDSSwiftSerializable {}
// This class can be used to convert database values to Swift values.
//
// TODO: Maybe we should rename this to a SDSSerializer protocol and
// move these methods to an extension?
public class SDSDeserialization {
private init() {}
// MARK: - Data
public class func required<T>(_ value: T?, name: String) throws -> T {
guard let value = value else {
owsFailDebug("Missing required field: \(name).")
throw SDSError.missingRequiredField
}
return value
}
// MARK: - Data
public class func optionalData(_ value: Data?, name: String) -> Data? {
return value
}
// MARK: - Date
public class func requiredDoubleAsDate(_ value: Double, name: String) -> Date {
return Date(timeIntervalSince1970: value)
}
public class func optionalDoubleAsDate(_ value: Double?, name: String) -> Date? {
guard let value = value else {
return nil
}
return requiredDoubleAsDate(value, name: name)
}
// MARK: - Numeric Primitive
public class func optionalNumericAsNSNumber<T>(_ value: T?, name: String, conversion: (T) -> NSNumber) -> NSNumber? {
guard let value = value else {
return nil
}
return conversion(value)
}
// MARK: - Blob
public class func optionalUnarchive<T: SDSSwiftSerializable>(_ encoded: Data?, name: String) throws -> T? {
guard let encoded = encoded else {
return nil
}
// The only time we ever return nil is if we fail the above guard condition.
// Explicitly declaring our expected return type helps the type checker pick the correct specialization
// since otherwise it will infer the result of `unarchive(_:name:)` to be Optional<T> and not T.
// (This isn't so important since if T conforms to SDSSwiftSerializable then Optional<T> does too, but
// it doesn't hurt to be explicit).
let result: T = try unarchive(encoded, name: name)
return result
}
public class func unarchive<T: SDSSwiftSerializable>(_ encoded: Data?, name: String) throws -> T {
guard let encoded = encoded else {
owsFailDebug("Missing required field: \(name).")
throw SDSError.missingRequiredField
}
do {
return try JSONDecoder().decode(T.self, from: encoded)
} catch {
owsFailDebug("Read failed[\(name)]: \(error).")
throw SDSError.invalidValue
}
}
public class func optionalUnarchive<T: Any>(_ encoded: Data?, name: String) throws -> T? {
guard let encoded = encoded else {
return nil
}
return try unarchive(encoded, name: name)
}
public class func unarchive<T: Any>(_ encoded: Data?, name: String) throws -> T {
guard let encoded = encoded else {
owsFailDebug("Missing required field: \(name).")
throw SDSError.missingRequiredField
}
do {
guard let decoded = try NSKeyedUnarchiver.unarchiveTopLevelObjectWithData(encoded) as? T else {
owsFailDebug("Invalid value: \(name).")
throw SDSError.invalidValue
}
return decoded
} catch {
owsFailDebug("Read failed[\(name)]: \(error).")
throw SDSError.invalidValue
}
}
}