Update ^C Handling during upload|download operations

* Update ^C Handling during upload|download operations

src/curlEngine.d

@@ -161,13 +161,14 @@ class CurlResponse {
 
 class CurlEngine {
 
-	__gshared CurlEngine[] curlEnginePool;
+	// Shared pool of CurlEngine instances accessible across all threads
+	__gshared CurlEngine[] curlEnginePool; // __gshared is used to declare a variable that is shared across all threads
 	
 	HTTP http;
+	File uploadFile;
+	CurlResponse response;
 	bool keepAlive;
 	ulong dnsTimeout;
-	CurlResponse response;
-	File uploadFile;
 	string internalThreadId;
 	
     this() {
@@ -176,30 +177,26 @@ class CurlEngine {
 		internalThreadId = generateAlphanumericString();
     }
 
-	~this() {
 	// The destructor should only clean up resources owned directly by this instance
-		addLogEntry("CurlEngine DESTRUCTOR CALLED", ["debug"]);
-		addLogEntry("CurlEngine DESTRUCTOR CALLED");
-	
-		// Avoid modifying or destroying shared/static resources here
+	~this() {
+		// Is the file still open?
 		if (uploadFile.isOpen()) {
 			uploadFile.close();
 		}
 		
-		// Cleanup class memory usage
-		object.destroy(uploadFile); // Destroy, however we cant set to null
+		// Is 'response' cleared?
+		if (response !is null) {
 			object.destroy(response); // Destroy, then set to null
 			response = null;
-		internalThreadId = null;
+		}
 		
 		// Is the actual http instance is stopped?
 		if (!http.isStopped) {
-			// instance was not stopped .. need to stop it
-			addLogEntry("CurlEngine DESTRUCTOR HTTP INSTANCE WAS NOT STOPPED - STOPPING", ["debug"]);
+			// HTTP instance was not stopped .. need to stop it
 			http.shutdown();
-		}
 			object.destroy(http); // Destroy, however we cant set to null
 		}
+    }
 		
 	static CurlEngine getCurlInstance() {
 		synchronized (CurlEngine.classinfo) {
@@ -232,6 +229,7 @@ class CurlEngine {
         synchronized (CurlEngine.classinfo) {
 			// What is the current pool size
 			addLogEntry("CURL ENGINES TO RELEASE: " ~ to!string(curlEnginePool.length), ["debug"]);
+			addLogEntry("CURL ENGINES TO RELEASE: " ~ to!string(curlEnginePool.length));
 		
             // Safely iterate and clean up each CurlEngine instance
 			foreach (curlEngineInstance; curlEnginePool) {
@@ -253,12 +251,11 @@ class CurlEngine {
 
     // Destroy all curl instances
 	static void destroyAllCurlInstances() {
+		
 		addLogEntry("DESTROY ALL CURL ENGINES", ["debug"]);
+		addLogEntry("DESTROY ALL CURL ENGINES");
 		// Release all 'curl' instances
 		releaseAllCurlInstances();
-		// Destroy curlEnginePool, set to null 
-		object.destroy(curlEnginePool);
-		curlEnginePool = null;
     }
 
 	// We are releasing a curl instance back to the pool

src/log.d

@@ -53,6 +53,7 @@ class LogBuffer {
 			flushThread.start();
         }
 		
+		// The destructor should only clean up resources owned directly by this instance
 		~this() {
 			object.destroy(bufferLock);
 			object.destroy(condReady);

src/main.d

@@ -1367,13 +1367,8 @@ extern(C) nothrow @nogc @system void exitHandler(int value) {
 		assumeNoGC ( () {
 		addLogEntry("\nReceived termination signal, initiating cleanup");
 			// Wait for all parallel jobs that depend on the database to complete
-			
 			addLogEntry("Waiting for any existing upload|download process to complete");
-			taskPool.finish(true);
-			
-			// Force kill any running threads
-			//addLogEntry("Forcing any active thread to exit");
-			//taskPool.finish(false);
+			syncEngineInstance.shutdown();
 			
 			// Perform the shutdown process
 			performSynchronisedExitProcess("exitHandler");
@@ -1403,17 +1398,16 @@ void performSynchronisedExitProcess(string scopeCaller = null) {
 			shutdownOneDriveWebhook();
 			// Shutdown the client side filtering objects
 			shutdownSelectiveSync();
+			// Destroy all 'curl' instances
+			destroyCurlInstances();
 			// Shutdown the sync engine
 			shutdownSyncEngine();
 			// Shutdown any local filesystem monitoring
 			shutdownFilesystemMonitor();
 			// Shutdown the database
 			shutdownDatabase();
-			// Destroy all 'curl' instances
-			destroyCurlInstances();
 			// Shutdown the application configuration objects
 			shutdownAppConfig();
-			
 		} catch (Exception e) {
             addLogEntry("Error during performStandardExitProcess: " ~ e.toString(), ["error"]);
         }
@@ -1458,7 +1452,7 @@ void shutdownSelectiveSync() {
 void shutdownSyncEngine() {
     if (syncEngineInstance !is null) {
 		addLogEntry("Shutdown Sync Engine instance", ["debug"]);
-		//syncEngineInstance.shutdown(); - potentially need this and also check for a ~this() for class cleanup
+		syncEngineInstance.shutdown(); // Make sure any running thread completes first
         object.destroy(syncEngineInstance);
         syncEngineInstance = null;
     }

src/onedrive.d

@@ -111,18 +111,20 @@ class OneDriveApi {
 		siteSearchUrl = appConfig.globalGraphEndpoint ~ "/v1.0/sites?search";
 		siteDriveUrl = appConfig.globalGraphEndpoint ~ "/v1.0/sites/";
 
-
 		// Subscriptions
 		subscriptionUrl = appConfig.globalGraphEndpoint ~ "/v1.0/subscriptions";
 	}
 	
+	// The destructor should only clean up resources owned directly by this instance
 	~this() {
-		// We cant destroy 'appConfig' here as this leads to a segfault
-		object.destroy(curlEngine);
-		object.destroy(response);
+		if (curlEngine !is null) {
 			curlEngine = null;
+		} 
+		
+		if (response !is null) {
 			response = null;
 		}
+	}
 
 	// Initialise the OneDrive API class
 	bool initialise(bool keepAlive=true) {
@@ -353,12 +355,6 @@ class OneDriveApi {
 		return authorised;
 	}
 
-	// Reinitialise the OneDrive API class
-	bool reinitialise() {
-		releaseCurlEngine();
-		return initialise(this.keepAlive);
-	}
-	
 	// If the API has been configured correctly, print the items that been configured
 	void debugOutputConfiguredAPIItems() {
 		// Debug output of configured URL's
@@ -1120,7 +1116,6 @@ class OneDriveApi {
 
 	// Wrapper function for all requests to OneDrive API
 	// - This should throw a OneDriveException so that this exception can be handled appropriately elsewhere in the application
-	
 	private JSONValue oneDriveErrorHandlerWrapper(CurlResponse delegate(CurlResponse response) executer, bool validateJSONResponse, string callingFunction, int lineno) {
 		// Create a new 'curl' response
 		response = new CurlResponse();

src/sync.d

@@ -185,7 +185,7 @@ class SyncEngine {
 	this(ApplicationConfig appConfig, ItemDatabase itemDB, ClientSideFiltering selectiveSync) {
 	
 		// Create the specific task pool to process items in parallel
-		this.processPool = new TaskPool(to!int(appConfig.getValueLong("threads")));
+		processPool = new TaskPool(to!int(appConfig.getValueLong("threads")));
 		addLogEntry("PROCESS POOL WORKER THREADS: " ~ to!string(processPool.size), ["debug"]);
 		
 		// Configure the class varaible to consume the application configuration
@@ -302,21 +302,13 @@ class SyncEngine {
 		}
 	}
 	
+	// The destructor should only clean up resources owned directly by this instance
 	~this() {
-		this.processPool.finish(true);
-		object.destroy(this.processPool); // Destroy, then set to null
-		this.processPool = null;
-		object.destroy(this.appConfig); // Destroy, then set to null
-		this.appConfig = null;
-		object.destroy(this.itemDB); // Destroy, then set to null
-		this.itemDB = null;
-		object.destroy(this.selectiveSync); // Destroy, then set to null
-		this.selectiveSync = null;
+		processPool.finish(true);
 	}
 	
 	// Initialise the Sync Engine class
 	bool initialise() {
-
 		// Control whether the worker threads are daemon threads. A daemon thread is automatically terminated when all non-daemon threads have terminated.
 		processPool.isDaemon(true);
 
@@ -387,15 +379,15 @@ class SyncEngine {
 		
 		// Shutdown this API instance, as we will create API instances as required, when required
 		oneDriveApiInstance.releaseCurlEngine();
-		
-		// Free object and memory
-		//object.destroy(oneDriveApiInstance);
-		//oneDriveApiInstance = null;
-		
-		
 		return true;
 	}
 	
+	// Shutdown the sync engine, wait for anything in processPool to complete
+	void shutdown() {
+		addLogEntry("SYNC-ENGINE: Waiting for all internal threads to complete", ["debug"]);
+		processPool.finish(true);
+	}
+	
 	// Get Default Drive Details for this Account
 	void getDefaultDriveDetails() {