[#472] CompactBlockBatchScanningOperation to async (#505)

- CompactBlockBatchScanningOperation operation's main reimplemented to be Task based

[472] CompactBlockBatchScanningOperation to async

cleanup

[472] CompactBlockBatchScanningOperation to async (505)

- CompactBlockBatchScanningOperation wrapped to Task

Sources/ZcashLightClientKit/Block/Processor/CompactBlockDownloadOperation.swift

@@ -194,10 +194,11 @@ class CompactBlockBatchDownloadOperation: ZcashOperation {
     override var isAsynchronous: Bool { false }
     
     private var batch: Int
+    private var done = false
     private var maxRetries: Int
     private var storage: CompactBlockStorage
     private var service: LightWalletService
-    private var cancelable: CancellableCall?
+    private var cancelableTask: Task<Void, Error>?
     private var startHeight: BlockHeight
     private var targetHeight: BlockHeight
 
@@ -229,8 +230,10 @@ class CompactBlockBatchDownloadOperation: ZcashOperation {
             return
         }
         self.startedHandler?()
+        
+        cancelableTask = Task {
             do {
-            let localDownloadedHeight = try self.storage.latestHeight()
+                let localDownloadedHeight = try await self.storage.latestHeightAsync()
                 
                 if localDownloadedHeight != BlockHeight.empty() && localDownloadedHeight > startHeight {
                     LoggerProxy.warn("provided startHeight (\(startHeight)) differs from local latest downloaded height (\(localDownloadedHeight))")
@@ -257,7 +260,12 @@ class CompactBlockBatchDownloadOperation: ZcashOperation {
                     
                     repeat {
                         do {
-                        let blocks = try service.blockRange(range)
+                            let stream: AsyncThrowingStream<ZcashCompactBlock, Error> = service.blockRange(range)
+
+                            var blocks: [ZcashCompactBlock] = []
+                            for try await compactBlock in stream {
+                                blocks.append(compactBlock)
+                            }
                             try storage.insert(blocks)
                             success = true
                         } catch {
@@ -283,18 +291,24 @@ class CompactBlockBatchDownloadOperation: ZcashOperation {
                     
                     currentHeight = range.upperBound + 1
                 }
+                self.done = true
             } catch {
                 self.fail(error: error)
             }
         }
         
+        while !done && !isCancelled {
+            sleep(1)
+        }
+    }
+
     override func fail(error: Error? = nil) {
-        self.cancelable?.cancel()
+        self.cancelableTask?.cancel()
         super.fail(error: error)
     }
 
     override func cancel() {
-        self.cancelable?.cancel()
+        self.cancelableTask?.cancel()
         super.cancel()
     }
 

Sources/ZcashLightClientKit/Block/Processor/CompactBlockScanningOperation.swift

@@ -125,6 +125,8 @@ class CompactBlockBatchScanningOperation: ZcashOperation {
     private var blockRange: CompactBlockRange
     private var transactionRepository: TransactionRepository
     private var network: NetworkType
+    private var cancelableTask: Task<Void, Error>?
+    private var done = false
 
     private weak var progressDelegate: CompactBlockProgressDelegate?
     
@@ -157,6 +159,7 @@ class CompactBlockBatchScanningOperation: ZcashOperation {
 
         self.startedHandler?()
 
+        cancelableTask = Task {
             do {
                 if batchSize == 0 {
                     let scanStartTime = Date()
@@ -224,15 +227,26 @@ class CompactBlockBatchScanningOperation: ZcashOperation {
                             LoggerProxy.debug("Scanned \(heightCount) blocks in \(seconds) seconds")
                         }
                     } while !self.isCancelled && scannedNewBlocks && lastScannedHeight < targetScanHeight
+                    self.done = true
                 }
             } catch {
                 scanFailed(error)
             }
         }
         
+        while !done && !isCancelled {
+            sleep(1)
+        }
+    }
+    
     func scanFailed(_ error: Error) {
-        self.error = error
+        self.cancelableTask?.cancel()
         LoggerProxy.debug("block scanning failed with error: \(String(describing: self.error))")
-        self.fail()
+        super.fail(error: error)
+    }
+    
+    override func cancel() {
+        self.cancelableTask?.cancel()
+        super.cancel()
     }
 }