Merge pull request #1332 from lixiang1994/master

解决主线程扫描数据耗时问题

Sources/Image/ImageProgressive.swift

@@ -103,19 +103,25 @@ final class ImageProgressiveProvider: DataReceivingSideEffect {
                     self.refresh(image)
                 }
             }
+            
+            let semaphore = DispatchSemaphore(value: 0)
+            var onShouldApply: Bool = false
+            
+            CallbackQueue.mainAsync.execute {
+                onShouldApply = self.onShouldApply()
+                semaphore.signal()
+            }
+            semaphore.wait()
+            guard onShouldApply else {
+                self.queue.clean()
+                completion()
+                return
+            }
 
-            CallbackQueue.mainCurrentOrAsync.execute {
-                guard self.onShouldApply() else {
-                    self.queue.clean()
-                    completion()
-                    return
-                }
-
-                if self.option.isFastestScan {
-                    decode(self.decoder.scanning(data) ?? Data())
-                } else {
-                    self.decoder.scanning(data).forEach { decode($0) }
-                }
+            if self.option.isFastestScan {
+                decode(self.decoder.scanning(data) ?? Data())
+            } else {
+                self.decoder.scanning(data).forEach { decode($0) }
             }
         }
     }
@@ -256,8 +262,7 @@ private final class ImageProgressiveDecoder {
 private final class ImageProgressiveSerialQueue {
     typealias ClosureCallback = ((@escaping () -> Void)) -> Void
     
-    private let queue: DispatchQueue = //DispatchQueue.main
-        .init(label: "com.onevcat.Kingfisher.ImageProgressive.SerialQueue")
+    private let queue: DispatchQueue = .init(label: "com.onevcat.Kingfisher.ImageProgressive.SerialQueue")
     private var items: [DispatchWorkItem] = []
     private var notify: (() -> Void)?
     private var lastTime: TimeInterval?