69 lines
2.6 KiB
Swift
69 lines
2.6 KiB
Swift
// Copyright 2018 Google Inc. All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at:
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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import Foundation
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public extension Promise {
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/// Provides a new promise to recover in case `self` gets rejected.
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/// - parameters:
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/// - queue: A queue to execute `recovery` block on.
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/// - recovery: A block to handle the error that `self` was rejected with.
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/// - returns: A new pending promise to use instead of the rejected one that gets resolved with
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/// the same resolution as the promise returned from `recovery` block.
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@discardableResult
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func recover(
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on queue: DispatchQueue = .promises,
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_ recovery: @escaping (Error) throws -> Promise
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) -> Promise {
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let promise = Promise(objCPromise.__onQueue(queue, recover: {
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do {
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// Convert `NSError` to `PromiseError`, if applicable.
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let error = PromiseError($0) ?? $0
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return try recovery(error).objCPromise
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} catch let error {
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return error as NSError
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}
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}))
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// Keep Swift wrapper alive for chained promise until `ObjCPromise` counterpart is resolved.
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objCPromise.__addPendingObject(promise)
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return promise
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}
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/// Provides a new promise to recover in case `self` gets rejected.
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/// - parameters:
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/// - queue: A queue to execute `recovery` block on.
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/// - recovery: A block to handle the error that `self` was rejected with.
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/// - returns: A new pending promise to use instead of the rejected one that gets resolved with
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/// the value returned from `recovery` block.
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@discardableResult
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func recover(
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on queue: DispatchQueue = .promises,
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_ recovery: @escaping (Error) throws -> Value
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) -> Promise {
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let promise = Promise(objCPromise.__onQueue(queue, recover: {
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do {
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// Convert `NSError` to `PromiseError`, if applicable.
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let error = PromiseError($0) ?? $0
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return Promise<Value>.asAnyObject(try recovery(error)) as Any
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} catch let error {
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return error as NSError
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}
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}))
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// Keep Swift wrapper alive for chained promise until `ObjCPromise` counterpart is resolved.
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objCPromise.__addPendingObject(promise)
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return promise
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}
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}
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