86 lines
4.2 KiB
Swift
86 lines
4.2 KiB
Swift
/*
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The MIT License (MIT)
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Copyright (c) 2015-present Badoo Trading Limited.
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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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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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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 UIKit
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protocol PhotosInputCellProviderProtocol {
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func cellForItemAtIndexPath(_ indexPath: IndexPath) -> UICollectionViewCell
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}
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class PhotosInputPlaceholderCellProvider: PhotosInputCellProviderProtocol {
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private let reuseIdentifier = "PhotosPlaceholderCellProvider"
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private let collectionView: UICollectionView
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init(collectionView: UICollectionView) {
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self.collectionView = collectionView
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self.collectionView.register(PhotosInputPlaceholderCell.self, forCellWithReuseIdentifier: self.reuseIdentifier)
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}
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func cellForItemAtIndexPath(_ indexPath: IndexPath) -> UICollectionViewCell {
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return self.collectionView.dequeueReusableCell(withReuseIdentifier: self.reuseIdentifier, for: indexPath)
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}
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}
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class PhotosInputCellProvider: PhotosInputCellProviderProtocol {
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private let reuseIdentifier = "PhotosCellProvider"
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private let collectionView: UICollectionView
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private let dataProvider: PhotosInputDataProviderProtocol
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init(collectionView: UICollectionView, dataProvider: PhotosInputDataProviderProtocol) {
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self.dataProvider = dataProvider
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self.collectionView = collectionView
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self.collectionView.register(PhotosInputCell.self, forCellWithReuseIdentifier: self.reuseIdentifier)
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}
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func cellForItemAtIndexPath(_ indexPath: IndexPath) -> UICollectionViewCell {
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let cell = self.collectionView.dequeueReusableCell(withReuseIdentifier: self.reuseIdentifier, for: indexPath) as! PhotosInputCell
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self.configureCell(cell, atIndexPath: indexPath)
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return cell
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}
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private let previewRequests = NSMapTable<PhotosInputCell, NSNumber>.weakToStrongObjects()
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private func configureCell(_ cell: PhotosInputCell, atIndexPath indexPath: IndexPath) {
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if let requestID = self.previewRequests.object(forKey: cell) {
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self.previewRequests.removeObject(forKey: cell)
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self.dataProvider.cancelPreviewImageRequest(requestID.int32Value)
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}
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let index = indexPath.item - 1
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let targetSize = cell.bounds.size
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var imageProvidedSynchronously = true
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var requestID: Int32 = -1
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requestID = self.dataProvider.requestPreviewImageAtIndex(index, targetSize: targetSize) { [weak self, weak cell] image in
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guard let sSelf = self, let sCell = cell else { return }
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// We can get here even afer calling cancelPreviewImageRequest (looks liek a race condition in PHImageManager)
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// Also, according to PHImageManager's documentation, this block can be called several times: we may receive an image with a low quality and then receive an update with a better one
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// This can also be called before returning from requestPreviewImageAtIndex (synchronously) if the image is cached by PHImageManager
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let imageIsForThisCell = imageProvidedSynchronously || sSelf.previewRequests.object(forKey: sCell)?.int32Value == requestID
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if imageIsForThisCell {
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sCell.image = image
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}
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}
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imageProvidedSynchronously = false
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self.previewRequests.setObject(NSNumber(value: requestID), forKey:cell)
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}
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}
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