fix gif caching

Pocket Poster/Packages/GIFImage/Sources/domain/CGImageSourceFrameSequence.swift

@@ -0,0 +1,46 @@
+//
+//  File.swift
+//  
+//
+//  Created by Igor Ferreira on 05/04/2022.
+//
+
+import Foundation
+import ImageIO
+
+public actor CGImageSourceFrameSequence: AsyncSequence {
+    public typealias Element = ImageFrame
+
+    public enum LoadError: Error {
+        case invalidData
+        case emptyData
+    }
+
+    public let source: CGImageSource
+
+    public init(data: Data) throws {
+        guard let source = CGImageSourceCreateWithData(data as CFData, nil) else {
+            throw LoadError.invalidData
+        }
+
+        switch CGImageSourceGetStatus(source) {
+        case .statusComplete: break
+        case .statusReadingHeader: break
+        case .statusIncomplete: throw LoadError.emptyData
+        case .statusInvalidData: throw LoadError.invalidData
+        case .statusUnexpectedEOF: throw LoadError.invalidData
+        case .statusUnknownType: throw LoadError.invalidData
+        @unknown default: throw LoadError.invalidData
+        }
+
+        self.init(source: source)
+    }
+
+    public init(source: CGImageSource) {
+        self.source = source
+    }
+
+    nonisolated public func makeAsyncIterator() -> CGImageSourceIterator {
+        CGImageSourceIterator(source: source)
+    }
+}