first commit

node_modules/expo-image/ios/Loaders/PhotoLibraryAssetLoader.swift

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+import Photos
+import Dispatch
+import SDWebImage
+import ExpoModulesCore
+
+/**
+ A custom loader for assets from the Photo Library. It handles all urls with the `ph` scheme.
+ */
+final class PhotoLibraryAssetLoader: NSObject, SDImageLoader {
+  // MARK: - SDImageLoader
+
+  func canRequestImage(for url: URL?) -> Bool {
+    return isPhotoLibraryAssetUrl(url)
+  }
+
+  func requestImage(
+    with url: URL?,
+    options: SDWebImageOptions = [],
+    context: SDWebImageContext?,
+    progress progressBlock: SDImageLoaderProgressBlock?,
+    completed completedBlock: SDImageLoaderCompletedBlock? = nil
+  ) -> SDWebImageOperation? {
+    guard isPhotoLibraryStatusAuthorized() else {
+      let error = makeNSError(description: "Unauthorized access to the Photo Library")
+      completedBlock?(nil, nil, error, false)
+      return nil
+    }
+    let operation = PhotoLibraryAssetLoaderOperation()
+
+    DispatchQueue.global(qos: .userInitiated).async {
+      guard let url = url, let assetLocalIdentifier = assetLocalIdentifier(fromUrl: url) else {
+        let error = makeNSError(description: "Unable to obtain the asset identifier from the url: '\(String(describing: url?.absoluteString))'")
+        completedBlock?(nil, nil, error, false)
+        return
+      }
+      guard let asset = PHAsset.fetchAssets(withLocalIdentifiers: [assetLocalIdentifier], options: .none).firstObject else {
+        let error = makeNSError(description: "Asset with identifier '\(assetLocalIdentifier)' not found in the Photo Library")
+        completedBlock?(nil, nil, error, false)
+        return
+      }
+      operation.requestId = requestAsset(
+        asset,
+        url: url,
+        context: context,
+        progressBlock: progressBlock,
+        completedBlock: completedBlock
+      )
+    }
+    return operation
+  }
+
+  func shouldBlockFailedURL(with url: URL, error: Error) -> Bool {
+    // The lack of permission is one of the reasons of failed request,
+    // but in that single case we don't want to blacklist the url as
+    // the permission might be granted later and then the retry should be possible.
+    return isPhotoLibraryStatusAuthorized()
+  }
+}
+
+/**
+ Returns a bool value whether the given url references the Photo Library asset.
+ */
+internal func isPhotoLibraryAssetUrl(_ url: URL?) -> Bool {
+  return url?.scheme == "ph"
+}
+
+/**
+ Returns the local identifier of the asset from the given `ph://` url.
+ These urls have the form of "ph://26687849-33F9-4402-8EC0-A622CD011D70",
+ where the asset local identifier is used as the host part.
+ */
+private func assetLocalIdentifier(fromUrl url: URL) -> String? {
+  return url.host
+}
+
+/**
+ Checks whether the app is authorized to read the Photo Library.
+ */
+private func isPhotoLibraryStatusAuthorized() -> Bool {
+  let status = PHPhotoLibrary.authorizationStatus(for: .readWrite)
+  return status == .authorized || status == .limited
+}
+
+/**
+ Requests the image of the given asset object and returns the request identifier.
+ */
+private func requestAsset(
+  _ asset: PHAsset,
+  url: URL,
+  context: SDWebImageContext?,
+  progressBlock: SDImageLoaderProgressBlock?,
+  completedBlock: SDImageLoaderCompletedBlock?
+) -> PHImageRequestID {
+  let options = PHImageRequestOptions()
+  options.isSynchronous = false
+  options.version = .current
+  options.deliveryMode = .highQualityFormat
+  options.resizeMode = .fast
+  options.normalizedCropRect = .zero
+  options.isNetworkAccessAllowed = true
+
+  if let progressBlock = progressBlock {
+    options.progressHandler = { progress, _, _, _ in
+      // The `progress` is a double from 0.0 to 1.0, but the loader needs integers so we map it to 0...100 range
+      let progressPercentage = Int((progress * 100.0).rounded())
+      progressBlock(progressPercentage, 100, url)
+    }
+  }
+
+  var targetSize = PHImageManagerMaximumSize
+
+  // We compute the minimal size required to display the image to avoid having to downsample it later
+  if let scale = context?[ImageView.screenScaleKey] as? Double,
+    let containerSize = context?[ImageView.frameSizeKey] as? CGSize,
+    let contentFit = context?[ImageView.contentFitKey] as? ContentFit {
+    targetSize = idealSize(
+      contentPixelSize: CGSize(width: asset.pixelWidth, height: asset.pixelHeight),
+      containerSize: containerSize,
+      scale: scale,
+      contentFit: contentFit
+    ).rounded(.up) * scale
+  }
+
+  return PHImageManager.default().requestImage(
+    for: asset,
+    targetSize: targetSize,
+    contentMode: .aspectFit,
+    options: options,
+    resultHandler: { image, info in
+      // This value can be `true` only when network access is allowed and the photo is stored in the iCloud.
+      let isDegraded: Bool = info?[PHImageResultIsDegradedKey] as? Bool ?? false
+
+      completedBlock?(image, nil, nil, !isDegraded)
+    }
+  )
+}
+
+/**
+ Loader operation specialized for the Photo Library by keeping the request identifier.
+ */
+private class PhotoLibraryAssetLoaderOperation: NSObject, SDWebImageOperation {
+  var canceled: Bool = false
+  var requestId: PHImageRequestID?
+
+  // MARK: - SDWebImageOperation
+
+  func cancel() {
+    if let requestId = requestId {
+      PHImageManager.default().cancelImageRequest(requestId)
+    }
+    canceled = true
+  }
+}