110 lines
3.4 KiB
Swift
110 lines
3.4 KiB
Swift
//
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// ImageDataCache.swift
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// Tusker
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//
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// Created by Shadowfacts on 1/16/21.
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// Copyright © 2021 Shadowfacts. All rights reserved.
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//
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import UIKit
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class ImageDataCache {
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private let memory: MemoryCache<Entry>
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let disk: DiskCache<Data>?
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private let storeOriginalDataInMemory: Bool
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private let desiredPixelSize: CGSize?
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init(name: String, memoryExpiry: CacheExpiry, diskExpiry: CacheExpiry?, storeOriginalDataInMemory: Bool, desiredPixelSize: CGSize?) {
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self.memory = MemoryCache(defaultExpiry: memoryExpiry)
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if let diskExpiry = diskExpiry {
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self.disk = try! DiskCache(name: name, defaultExpiry: diskExpiry)
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} else {
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self.disk = nil
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}
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self.storeOriginalDataInMemory = storeOriginalDataInMemory
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self.desiredPixelSize = desiredPixelSize
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}
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func has(_ key: String) throws -> Bool {
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if memory.existsObject(forKey: key) {
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return true
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} else if let disk = self.disk,
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try disk.existsObject(forKey: key) {
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return true
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} else {
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return false
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}
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}
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func get(_ key: String, loadOriginal: Bool) throws -> Entry? {
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if storeOriginalDataInMemory || !loadOriginal,
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let memoryEntry = try? memory.object(forKey: key) {
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return memoryEntry
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} else if let disk = self.disk,
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let data = try? disk.object(forKey: key),
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let image = UIImage(data: data) {
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return Entry(data: data, image: image)
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} else {
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return nil
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}
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}
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func getImage(_ key: String) throws -> UIImage? {
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return try get(key, loadOriginal: false)?.image
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}
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func getData(_ key: String) throws -> Data? {
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return try get(key, loadOriginal: false)?.data
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}
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func set(_ key: String, data: Data, image: UIImage?) throws {
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guard let image = scaleImageIfDesired(data: data) ?? image else { return }
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let entry = Entry(data: storeOriginalDataInMemory ? data : nil, image: image)
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memory.setObject(entry, forKey: key)
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if let disk = self.disk {
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try disk.setObject(data, forKey: key)
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}
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}
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func removeAll() throws {
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memory.removeAll()
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try? disk?.removeAll()
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}
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// TODO: consider removing this and letting ImageCache just use the UIImage thumbnailing API
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private func scaleImageIfDesired(data: Data) -> UIImage? {
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guard let desiredPixelSize = desiredPixelSize,
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let source = CGImageSourceCreateWithData(data as CFData, [kCGImageSourceShouldCache: false] as CFDictionary) else {
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return nil
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}
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let maxDimension = max(desiredPixelSize.width, desiredPixelSize.height)
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let downsampleOptions: [CFString: Any] = [
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kCGImageSourceCreateThumbnailFromImageAlways: true,
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kCGImageSourceShouldCacheImmediately: true,
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kCGImageSourceCreateThumbnailWithTransform: true,
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kCGImageSourceThumbnailMaxPixelSize: maxDimension
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]
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if let downsampled = CGImageSourceCreateThumbnailAtIndex(source, 0, downsampleOptions as CFDictionary) {
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return UIImage(cgImage: downsampled)
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} else {
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return nil
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}
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}
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}
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extension ImageDataCache {
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struct Entry {
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let data: Data?
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let image: UIImage
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}
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}
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