修复可能的野指针crash

BFFramework/Classes/PQGPUImage/akfilters/Tools/PQCompositionExporter.swift

@@ -14,7 +14,7 @@ import BFCommonKit
 public class PQCompositionExporter {
     public var progressClosure: ((_ currTime: Float, _ duration: Float, _ progress: Float) -> Void)?
 
-    public var completion: ((_ url: URL) -> Void)?
+    public var completion: ((_ url: URL?) -> Void)?
 
     public let asset: AVAsset
     public let videoComposition: AVVideoComposition?
@@ -297,14 +297,14 @@ public class PQCompositionExporter {
 
     public func start(playeTimeRange:CMTimeRange = CMTimeRange.init()) {
         input?.completion = { [unowned self] in
-            self.output?.finishRecording { [unowned self] in
+            self.output?.finishRecording { [weak self] in
                 BFLog(message: "导出视频完成发通知")
                 DispatchQueue.main.async {
-                    if let url = self.tmpExportURL {
-                        self.handleCaption(for: AVURLAsset(url: url, options: nil))
+                    if let url = self?.tmpExportURL {
+                        self?.handleCaption(for: AVURLAsset(url: url, options: nil))
                     } else {
-                        self.progressClosure?(0, 0, 1)
-                        self.completion?(self.exportURL)
+                        self?.progressClosure?(0, 0, 1)
+                        self?.completion?(self?.exportURL)
                     }
                 }
             }