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| public typealias HandleAction<T> = (T) throws -> () | |
| public protocol ErrorHandleable: class { | |
| func `throw`(_: Error, finally: @escaping (Bool) -> Void) | |
| func `catch`(action: @escaping HandleAction<Error>) -> ErrorHandleable | |
| } | |
| public class ErrorHandler: ErrorHandleable { | |
| private var parent: ErrorHandler? | |
| private let action: HandleAction<Error> | |
| convenience init(action: @escaping HandleAction<Error> = { throw $0 }) { | |
| self.init(action: action, parent: nil) | |
| } | |
| private init(action: @escaping HandleAction<Error>, parent: ErrorHandler? = nil) { | |
| self.action = action | |
| self.parent = parent | |
| } | |
| public func `throw`(_ error: Error, finally: @escaping (Bool) -> Void) { | |
| `throw`(error, previous: [], finally: finally) | |
| } | |
| private func `throw`(_ error: Error, previous: [ErrorHandler], finally: ((Bool) -> Void)? = nil) { | |
| if let parent = parent { | |
| parent.`throw`(error, previous: previous + [self], finally: finally) | |
| return | |
| } | |
| serve(error, next: AnyCollection(previous.reversed()), finally: finally) | |
| } | |
| private func serve(_ error: Error, next: AnyCollection<ErrorHandler>, finally: ((Bool) -> Void)? = nil) { | |
| do { | |
| try action(error) | |
| finally?(true) | |
| } catch { | |
| if let nextHandler = next.first { | |
| nextHandler.serve(error, next: next.dropFirst(), finally: finally) | |
| } else { | |
| finally?(false) | |
| } | |
| } | |
| } | |
| public func `catch`(action: @escaping HandleAction<Error>) -> ErrorHandleable { | |
| return ErrorHandler(action: action, parent: self) | |
| } | |
| } | |
| // | |
| // Protocol extensions for convenience API | |
| public extension ErrorHandleable { | |
| func `do`<A>(_ section: () throws -> A) { | |
| do { | |
| try section() | |
| } catch { | |
| `throw`(error) | |
| } | |
| } | |
| } | |
| public extension ErrorHandleable { | |
| func `throw`(_ error: Error) { | |
| `throw`(error, finally: { _ in }) | |
| } | |
| } | |
| public extension ErrorHandleable { | |
| func `catch`<K:Error>(_ type: K.Type, action: @escaping HandleAction<K>) -> ErrorHandleable { | |
| return `catch`(action: { (e) in | |
| if let k = e as? K { | |
| try action(k) | |
| } else { | |
| throw e | |
| } | |
| }) | |
| } | |
| func `catch`<K:Error>(_ value: K, action: @escaping HandleAction<K>) -> ErrorHandleable where K: Equatable { | |
| return `catch`(action: { (e) in | |
| if let k = e as? K, k == value { | |
| try action(k) | |
| } else { | |
| throw e | |
| } | |
| }) | |
| } | |
| } | |
| public extension ErrorHandleable { | |
| func listen(action: @escaping (Error) -> ()) -> ErrorHandleable { | |
| return `catch`(action: { e in | |
| action(e) | |
| throw e | |
| }) | |
| } | |
| func listen<K:Error>(_ type: K.Type, action: @escaping (K) -> ()) -> ErrorHandleable { | |
| return `catch`(type, action: { e in | |
| action(e) | |
| throw e | |
| }) | |
| } | |
| func listen<K:Error>(_ value: K, action: @escaping (K) -> ()) -> ErrorHandleable where K: Equatable { | |
| return `catch`(value, action: { e in | |
| action(e) | |
| throw e | |
| }) | |
| } | |
| } |
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