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Changelog-Changed: Use an optimized library for image loading Signed-off-by: William Casarin <jb55@jb55.com>profile-edit
William Casarin
2 years ago
17 changed files with 37 additions and 263 deletions
@ -1,193 +0,0 @@ |
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// |
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// ImageCache.swift |
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// damus |
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// |
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// Created by William Casarin on 2022-05-04. |
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// |
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import Foundation |
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import SwiftUI |
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import UIKit |
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enum ImageProcessingStatus { |
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case processing |
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case done |
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} |
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class ImageCache { |
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private let lock = NSLock() |
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private var state: [String: ImageProcessingStatus] = [:] |
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private func get_state(_ key: String) -> ImageProcessingStatus? { |
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lock.lock(); defer { lock.unlock() } |
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return state[key] |
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} |
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private func set_state(_ key: String, new_state: ImageProcessingStatus) { |
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lock.lock(); defer { lock.unlock() } |
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state[key] = new_state |
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} |
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lazy var cache: NSCache<NSString, UIImage> = { |
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let cache = NSCache<NSString, UIImage>() |
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cache.totalCostLimit = 1024 * 1024 * 100 // 100MB |
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return cache |
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}() |
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// simple polling until I can figure out a better way to do this |
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func wait_for_image(_ key: String) async { |
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while true { |
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let why_would_this_happen: ()? = try? await Task.sleep(nanoseconds: 100_000_000) // 100ms |
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if why_would_this_happen == nil { |
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return |
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} |
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if get_state(key) == .done { |
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return |
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} |
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} |
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} |
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func lookup_sync(key: String) -> UIImage? { |
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let status = get_state(key) |
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switch status { |
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case .done: |
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break |
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case .processing: |
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return nil |
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case .none: |
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return nil |
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} |
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if let decoded = cache.object(forKey: NSString(string: key)) { |
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return decoded |
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} |
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return nil |
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} |
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func lookup_or_load_image(key: String, url: URL?) async -> UIImage? { |
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if let img = await lookup(key: key) { |
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return img |
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} |
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guard let url = url else { |
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return nil |
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} |
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return await load_image(cache: self, from: url, key: key) |
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} |
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func get_cache_url(key: String, suffix: String, ext: String = "png") -> URL? { |
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let urls = FileManager.default.urls(for: .cachesDirectory, in: .userDomainMask) |
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guard let root = urls.first else { |
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return nil |
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} |
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return root.appendingPathComponent("\(key)\(suffix).\(ext)") |
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} |
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private func lookup_file_cache(key: String, suffix: String = "_pfp") -> UIImage? { |
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guard let img_file = get_cache_url(key: key, suffix: suffix) else { |
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return nil |
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} |
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guard let img = UIImage(contentsOfFile: img_file.path) else { |
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//print("failed to load \(key)\(suffix).png from file cache") |
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return nil |
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} |
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save_to_memory_cache(key: key, img: img) |
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return img |
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} |
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func lookup(key: String) async -> UIImage? { |
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let status = get_state(key) |
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switch status { |
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case .done: |
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break |
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case .processing: |
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await wait_for_image(key) |
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case .none: |
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return lookup_file_cache(key: key) |
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} |
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if let decoded = cache.object(forKey: NSString(string: key)) { |
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return decoded |
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} |
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return nil |
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} |
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func remove(key: String) { |
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lock.lock(); defer { lock.unlock() } |
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cache.removeObject(forKey: NSString(string: key)) |
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} |
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func insert(_ image: UIImage, key: String) async -> UIImage? { |
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let scale = await UIScreen.main.scale |
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let size = CGSize(width: PFP_SIZE * scale, height: PFP_SIZE * scale) |
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set_state(key, new_state: .processing) |
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let decoded_image = await image.byPreparingThumbnail(ofSize: size) |
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save_to_memory_cache(key: key, img: decoded_image ?? UIImage()) |
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if let img = decoded_image { |
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if !save_to_file_cache(key: key, img: img) { |
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print("failed saving \(key) pfp to file cache") |
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} |
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} |
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return decoded_image |
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} |
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func save_to_file_cache(key: String, img: UIImage, suffix: String = "_pfp") -> Bool { |
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guard let url = get_cache_url(key: key, suffix: suffix) else { |
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return false |
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} |
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guard let data = img.pngData() else { |
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return false |
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} |
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return (try? data.write(to: url)) != nil |
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} |
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func save_to_memory_cache(key: String, img: UIImage) { |
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lock.lock() |
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cache.setObject(img, forKey: NSString(string: key)) |
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state[key] = .done |
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lock.unlock() |
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} |
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} |
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func load_image(cache: ImageCache, from url: URL, key: String) async -> UIImage? { |
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guard let (data, _) = try? await URLSession.shared.data(from: url) else { |
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return nil |
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} |
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guard let img = UIImage(data: data) else { |
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return nil |
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} |
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return await cache.insert(img, key: key) |
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} |
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func hashed_hexstring(_ str: String) -> String { |
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guard let data = str.data(using: .utf8) else { |
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return str |
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} |
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return hex_encode(sha256(data)) |
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} |
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func pfp_cache_key(url: URL) -> String { |
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return hashed_hexstring(url.absoluteString) |
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} |
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