109 lines
3.7 KiB
Swift
109 lines
3.7 KiB
Swift
//
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// Copyright (c) 2017 Touch Instinct
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the Software), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED AS IS, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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//
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import RxSwift
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public typealias ResettableCursorType = CursorType & ResettableType
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public typealias ResettableCursorDataSource = ResettableCursorType & DataSourceProtocol
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public final class PaginationLoadingViewModel<C: ResettableCursorDataSource>:
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LoadingViewModel<PaginationLoadingViewModelConfiguration<C>>
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where C.ResultType == [C.Element] {
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private enum LoadType {
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case reload
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case retry
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case next
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}
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private let configuration: PaginationLoadingViewModelConfiguration<C>
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public required init(configuration: PaginationLoadingViewModelConfiguration<C>) {
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self.configuration = configuration
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super.init(configuration: configuration)
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}
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override public func reload() {
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load(.reload)
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}
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override public func retry() {
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load(.retry)
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}
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public func loadMore() {
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load(.next)
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}
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private func load(_ loadType: LoadType) {
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switch loadType {
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case .reload, .retry:
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configuration.resetDataSource()
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configuration.state = .loading(after: configuration.state)
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case .next:
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if case .exhausted = configuration.state {
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fatalError("You shouldn't call load(.next) after got .exhausted state!")
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}
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configuration.state = .loadingMore(after: configuration.state)
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}
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let currentDataSource = configuration.dataSource
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let currentRequestDisposable = configuration.loadingObservable
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.subscribeOn(configuration.scheduler)
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.subscribe(onSuccess: { [weak self] newItems in
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self?.onGot(result: newItems, from: currentDataSource)
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}, onError: { [weak self] error in
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self?.onGot(error: error)
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})
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configuration.storeCurrentRequestDisposable(currentRequestDisposable)
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}
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override func onGot(result: DataSourceType.ResultType, from dataSource: DataSourceType) {
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super.onGot(result: result, from: dataSource)
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if !configuration.isEmptyResult(result: result) && dataSource.exhausted {
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configuration.state = .exhausted
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}
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}
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override func onGot(error: Error) {
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if case .exhausted? = error as? CursorError, case .loading(let after) = configuration.state {
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switch after {
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case .initial, .empty: // cursor exhausted after creation
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configuration.state = .empty
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default:
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super.onGot(error: error)
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}
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} else {
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super.onGot(error: error)
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}
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}
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}
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