mirror of https://github.com/oxen-io/session-ios
Add OWSThumbnailService.
Matthew Chen
7 years ago
parent
1831f0b1f8
commit
ac4365e1c9
@ -0,0 +1,194 @@
|
|||||||
|
//
|
||||||
|
// Copyright (c) 2018 Open Whisper Systems. All rights reserved.
|
||||||
|
//
|
||||||
|
|
||||||
|
import Foundation
|
||||||
|
|
||||||
|
private struct OWSThumbnailRequest {
|
||||||
|
public typealias CompletionBlock = (UIImage) -> Void
|
||||||
|
|
||||||
|
let attachmentId: String
|
||||||
|
let thumbnailDimensionPoints: UInt
|
||||||
|
let completion: CompletionBlock
|
||||||
|
|
||||||
|
init(attachmentId: String, thumbnailDimensionPoints: UInt, completion: @escaping CompletionBlock) {
|
||||||
|
self.attachmentId = attachmentId
|
||||||
|
self.thumbnailDimensionPoints = thumbnailDimensionPoints
|
||||||
|
self.completion = completion
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
@objc public class OWSThumbnailService: NSObject {
|
||||||
|
|
||||||
|
// MARK: - Singleton class
|
||||||
|
|
||||||
|
@objc(shared)
|
||||||
|
public static let shared = OWSThumbnailService()
|
||||||
|
|
||||||
|
public typealias CompletionBlock = (UIImage) -> Void
|
||||||
|
|
||||||
|
private let serialQueue = DispatchQueue(label: "OWSThumbnailService")
|
||||||
|
|
||||||
|
private let dbConnection: YapDatabaseConnection
|
||||||
|
|
||||||
|
// This property should only be accessed on the serialQueue.
|
||||||
|
//
|
||||||
|
// We want to process requests in _reverse_ order in which they
|
||||||
|
// arrive so that we prioritize the most recent view state.
|
||||||
|
// This data structure is actually used like a stack.
|
||||||
|
private var thumbnailRequestQueue = [OWSThumbnailRequest]()
|
||||||
|
|
||||||
|
private override init() {
|
||||||
|
|
||||||
|
dbConnection = OWSPrimaryStorage.shared().newDatabaseConnection()
|
||||||
|
|
||||||
|
super.init()
|
||||||
|
|
||||||
|
SwiftSingletons.register(self)
|
||||||
|
}
|
||||||
|
|
||||||
|
private func canThumbnailAttachment(attachment: TSAttachmentStream) -> Bool {
|
||||||
|
guard attachment.isImage() else {
|
||||||
|
return false
|
||||||
|
}
|
||||||
|
guard !attachment.isAnimated() else {
|
||||||
|
return false
|
||||||
|
}
|
||||||
|
guard attachment.isValidImage() else {
|
||||||
|
return false
|
||||||
|
}
|
||||||
|
return true
|
||||||
|
}
|
||||||
|
|
||||||
|
// completion will only be called on success.
|
||||||
|
// completion will be called async on the main thread.
|
||||||
|
@objc public func ensureThumbnailForAttachmentId(attachmentId: String,
|
||||||
|
thumbnailDimensionPoints: UInt,
|
||||||
|
completion:@escaping CompletionBlock) {
|
||||||
|
guard attachmentId.count > 0 else {
|
||||||
|
owsFail("Empty attachment id.")
|
||||||
|
return
|
||||||
|
}
|
||||||
|
serialQueue.async {
|
||||||
|
let thumbnailRequest = OWSThumbnailRequest(attachmentId: attachmentId, thumbnailDimensionPoints: thumbnailDimensionPoints, completion: completion)
|
||||||
|
self.thumbnailRequestQueue.append(thumbnailRequest)
|
||||||
|
|
||||||
|
self.processNextRequestSync()
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
private func processNextRequestAsync() {
|
||||||
|
serialQueue.async {
|
||||||
|
self.processNextRequestSync()
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
// This should only be called on the serialQueue.
|
||||||
|
private func processNextRequestSync() {
|
||||||
|
guard !thumbnailRequestQueue.isEmpty else {
|
||||||
|
return
|
||||||
|
}
|
||||||
|
let thumbnailRequest = thumbnailRequestQueue.removeLast()
|
||||||
|
|
||||||
|
if let image = process(thumbnailRequest: thumbnailRequest) {
|
||||||
|
DispatchQueue.main.async {
|
||||||
|
thumbnailRequest.completion(image)
|
||||||
|
}
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
// This should only be called on the serialQueue.
|
||||||
|
private func process(thumbnailRequest: OWSThumbnailRequest) -> UIImage? {
|
||||||
|
var possibleAttachment: TSAttachmentStream?
|
||||||
|
self.dbConnection.read({ (transaction) in
|
||||||
|
possibleAttachment = TSAttachmentStream.fetch(uniqueId: thumbnailRequest.attachmentId, transaction: transaction)
|
||||||
|
})
|
||||||
|
guard let attachment = possibleAttachment else {
|
||||||
|
Logger.warn("Could not load attachment for thumbnailing.")
|
||||||
|
return nil
|
||||||
|
}
|
||||||
|
guard canThumbnailAttachment(attachment: attachment) else {
|
||||||
|
Logger.warn("Cannot thumbnail attachment.")
|
||||||
|
return nil
|
||||||
|
}
|
||||||
|
if let thumbnails = attachment.thumbnails {
|
||||||
|
for thumbnail in thumbnails {
|
||||||
|
if thumbnail.thumbnailDimensionPoints == thumbnailRequest.thumbnailDimensionPoints {
|
||||||
|
guard let filePath = attachment.path(for: thumbnail) else {
|
||||||
|
owsFail("Could not determine thumbnail path.")
|
||||||
|
return nil
|
||||||
|
}
|
||||||
|
guard let image = UIImage(contentsOfFile: filePath) else {
|
||||||
|
owsFail("Could not load thumbnail.")
|
||||||
|
return nil
|
||||||
|
}
|
||||||
|
return image
|
||||||
|
}
|
||||||
|
}
|
||||||
|
}
|
||||||
|
guard let originalFilePath = attachment.originalFilePath() else {
|
||||||
|
owsFail("Could not determine thumbnail path.")
|
||||||
|
return nil
|
||||||
|
}
|
||||||
|
guard let originalImage = UIImage(contentsOfFile: originalFilePath) else {
|
||||||
|
owsFail("Could not load original image.")
|
||||||
|
return nil
|
||||||
|
}
|
||||||
|
let originalSize = originalImage.size
|
||||||
|
guard originalSize.width > 0 && originalSize.height > 0 else {
|
||||||
|
owsFail("Original image has invalid size.")
|
||||||
|
return nil
|
||||||
|
}
|
||||||
|
var thumbnailSize = CGSize.zero
|
||||||
|
if originalSize.width > originalSize.height {
|
||||||
|
thumbnailSize.width = CGFloat(thumbnailRequest.thumbnailDimensionPoints)
|
||||||
|
thumbnailSize.height = round(CGFloat(thumbnailRequest.thumbnailDimensionPoints) * thumbnailSize.height / thumbnailSize.width)
|
||||||
|
} else {
|
||||||
|
thumbnailSize.width = round(CGFloat(thumbnailRequest.thumbnailDimensionPoints) * thumbnailSize.width / thumbnailSize.height)
|
||||||
|
thumbnailSize.height = CGFloat(thumbnailRequest.thumbnailDimensionPoints)
|
||||||
|
}
|
||||||
|
guard thumbnailSize.width > 0 && thumbnailSize.height > 0 else {
|
||||||
|
owsFail("Thumbnail has invalid size.")
|
||||||
|
return nil
|
||||||
|
}
|
||||||
|
guard originalSize.width < thumbnailSize.width &&
|
||||||
|
originalSize.height < thumbnailSize.height else {
|
||||||
|
owsFail("Thumbnail isn't smaller than the original.")
|
||||||
|
return nil
|
||||||
|
}
|
||||||
|
// We use UIGraphicsBeginImageContextWithOptions() to scale.
|
||||||
|
// Core Image would provide better quality (e.g. Lanczos) but
|
||||||
|
// at perf cost we don't want to pay. We could also use
|
||||||
|
// CoreGraphics directly, but I'm not sure there's any benefit.
|
||||||
|
guard let thumbnailImage = originalImage.resizedImage(to: thumbnailSize) else {
|
||||||
|
owsFail("Could not thumbnail image.")
|
||||||
|
return nil
|
||||||
|
}
|
||||||
|
guard let thumbnailData = UIImageJPEGRepresentation(thumbnailImage, 0.85) else {
|
||||||
|
owsFail("Could not convert thumbnail to JPEG.")
|
||||||
|
return nil
|
||||||
|
}
|
||||||
|
let temporaryDirectory = NSTemporaryDirectory()
|
||||||
|
let thumbnailFilename = "\(NSUUID().uuidString).jpg"
|
||||||
|
let thumbnailFilePath = (temporaryDirectory as NSString).appendingPathComponent(thumbnailFilename)
|
||||||
|
do {
|
||||||
|
try thumbnailData.write(to: NSURL.fileURL(withPath: thumbnailFilePath), options: .atomicWrite)
|
||||||
|
} catch let error as NSError {
|
||||||
|
owsFail("File write failed: \(thumbnailFilePath), \(error)")
|
||||||
|
return nil
|
||||||
|
}
|
||||||
|
// It should be safe to assume that an attachment will never end up with two thumbnails of
|
||||||
|
// the same size since:
|
||||||
|
//
|
||||||
|
// * Thumbnails are only added by this method.
|
||||||
|
// * This method checks for an existing thumbnail using the same connection.
|
||||||
|
// * This method is performed on the serial queue.
|
||||||
|
self.dbConnection.readWrite({ (transaction) in
|
||||||
|
attachment.update(withNewThumbnail: thumbnailFilePath,
|
||||||
|
thumbnailDimensionPoints: thumbnailRequest.thumbnailDimensionPoints,
|
||||||
|
size: thumbnailSize,
|
||||||
|
transaction: transaction)
|
||||||
|
})
|
||||||
|
return thumbnailImage
|
||||||
|
}
|
||||||
|
}
|
||||||
Loading…
Reference in New Issue