115 lines
3.8 KiB
Swift
115 lines
3.8 KiB
Swift
//
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// Copyright 2022 New Vector Ltd
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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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//
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import Foundation
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import Photos
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import UIKit
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enum ScreenshotDetectorError: String, Error {
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case loadFailed
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case notAuthorized
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}
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@MainActor
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class ScreenshotDetector {
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var callback: (@MainActor (UIImage?, Error?) -> Void)?
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/// Flag to whether ask for photos authorization by default if needed.
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var autoRequestPHAuthorization = false
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init() {
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startObservingScreenshots()
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}
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private func startObservingScreenshots() {
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NotificationCenter.default.addObserver(self,
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selector: #selector(userDidTakeScreenshot),
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name: UIApplication.userDidTakeScreenshotNotification,
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object: nil)
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}
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@objc private func userDidTakeScreenshot() {
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let authStatus = PHPhotoLibrary.authorizationStatus(for: .readWrite)
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if authStatus == .authorized {
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findScreenshot()
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} else if authStatus == .notDetermined, autoRequestPHAuthorization {
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Task {
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await self.handleAuthStatus(PHPhotoLibrary.requestAuthorization(for: .readWrite))
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}
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} else {
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fail(withError: ScreenshotDetectorError.notAuthorized)
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}
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}
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private func handleAuthStatus(_ status: PHAuthorizationStatus) {
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if status == .authorized {
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findScreenshot()
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} else {
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fail(withError: ScreenshotDetectorError.notAuthorized)
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}
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}
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private func findScreenshot() {
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if let asset = PHAsset.fetchLastScreenshot() {
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let imageManager = PHImageManager()
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imageManager.requestImage(for: asset,
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targetSize: PHImageManagerMaximumSize,
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contentMode: .default,
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options: PHImageRequestOptions.highQualitySyncLocal) { [weak self] image, _ in
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guard let image else {
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self?.fail(withError: ScreenshotDetectorError.loadFailed)
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return
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}
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self?.succeed(withImage: image)
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}
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} else {
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fail(withError: ScreenshotDetectorError.loadFailed)
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}
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}
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func succeed(withImage image: UIImage) {
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callback?(image, nil)
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}
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func fail(withError error: Error) {
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callback?(nil, error)
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}
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}
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extension PHAsset {
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static func fetchLastScreenshot() -> PHAsset? {
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let options = PHFetchOptions()
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options.fetchLimit = 1
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options.includeAssetSourceTypes = [.typeUserLibrary]
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options.wantsIncrementalChangeDetails = false
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options.predicate = NSPredicate(format: "(mediaSubtype & %d) != 0", PHAssetMediaSubtype.photoScreenshot.rawValue)
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options.sortDescriptors = [NSSortDescriptor(key: "creationDate", ascending: false)]
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return PHAsset.fetchAssets(with: .image, options: options).firstObject
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}
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}
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private extension PHImageRequestOptions {
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static var highQualitySyncLocal: PHImageRequestOptions {
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let options = PHImageRequestOptions()
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options.deliveryMode = .highQualityFormat
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options.isNetworkAccessAllowed = false
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options.isSynchronous = true
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return options
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}
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}
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