gui: Begin cancellation of Indexer

shared/concurrentqueue.h

@@ -3,7 +3,6 @@
 #include <QList>
 #include <QMutex>
 #include <QSemaphore>
-
 #define QUEUE_SIZE 10000
 template <class T> class ConcurrentQueue : protected QList<T>
 {

shared/dirscanworker.cpp

@@ -33,6 +33,9 @@ void DirScanWorker::run()
 			{
 				if(this->stopToken->load(std::memory_order_relaxed))
 				{
+					Logger::info() << "Received cancel request" << Qt::endl;
+					this->results.clear();
+					emit finished();
 					return;
 				}
 

shared/filescanworker.cpp

@@ -1,10 +1,12 @@
 #include "filescanworker.h"
 #include "logger.h"
-FileScanWorker::FileScanWorker(SqliteDbService &db, ConcurrentQueue<QString> &queue, int batchsize)
+FileScanWorker::FileScanWorker(SqliteDbService &db, ConcurrentQueue<QString> &queue, int batchsize,
+							   std::atomic<bool> &stopToken)
 {
 	this->dbService = &db;
 	this->queue = &queue;
 	this->batchsize = batchsize;
+	this->stopToken = &stopToken;
 }
 
 void FileScanWorker::run()
@@ -24,6 +26,11 @@ void FileScanWorker::run()
 			sfr = PROCESSFAIL; // well...
 		}
 		emit result({path, sfr});
+		if(stopToken->load(std::memory_order_relaxed)) // TODO: relaxed should suffice here, but recheck
+		{
+			emit finished();
+			return;
+		}
 	}
 	emit finished();
 }

shared/filescanworker.h

@@ -16,9 +16,10 @@ class FileScanWorker : public QObject, public QRunnable
 	SqliteDbService *dbService;
 	ConcurrentQueue<QString> *queue;
 	int batchsize;
+	std::atomic<bool> *stopToken;
 
   public:
-	FileScanWorker(SqliteDbService &db, ConcurrentQueue<QString> &queue, int batchsize);
+	FileScanWorker(SqliteDbService &db, ConcurrentQueue<QString> &queue, int batchsize, std::atomic<bool> &stopToken);
 	void run() override;
   signals:
 	void result(FileScanResult);

shared/indexer.cpp

@@ -34,6 +34,7 @@ void Indexer::beginIndexing()
 
 	this->dirScanner->scan();
 
+	this->workerCancellationToken.store(false, std::memory_order_seq_cst);
 	launchWorker(this->filePathTargetsQueue, this->filePathTargetsQueue.remaining());
 }
 
@@ -47,6 +48,12 @@ void Indexer::setTargetPaths(QVector<QString> pathsToScan)
 	this->pathsToScan = pathsToScan;
 }
 
+void Indexer::requestCancellation()
+{
+	this->dirScanner->cancel();
+	this->workerCancellationToken.store(true, std::memory_order_release);
+}
+
 IndexResult Indexer::getResult()
 {
 	return this->currentIndexResult;
@@ -55,11 +62,15 @@ IndexResult Indexer::getResult()
 void Indexer::dirScanFinished()
 {
 	Logger::info() << "Dir scan finished";
+	if(!isRunning())
+	{
+		emit finished();
+	}
 }
 
 void Indexer::launchWorker(ConcurrentQueue<QString> &queue, int batchsize)
 {
-	FileScanWorker *runnable = new FileScanWorker(*this->db, queue, batchsize);
+	FileScanWorker *runnable = new FileScanWorker(*this->db, queue, batchsize, this->workerCancellationToken);
 	connect(runnable, &FileScanWorker::result, this, &Indexer::processFileScanResult);
 	connect(runnable, &FileScanWorker::finished, this, &Indexer::processFinishedWorker);
 	++this->runningWorkers;
@@ -107,10 +118,14 @@ void Indexer::processFileScanResult(FileScanResult result)
 	}
 }
 
+bool Indexer::isRunning()
+{
+	return this->runningWorkers > 0 || this->dirScanner->isRunning();
+}
 void Indexer::processFinishedWorker()
 {
 	--this->runningWorkers;
-	if(this->runningWorkers == 0 && !this->dirScanner->isRunning())
+	if(!isRunning())
 	{
 		emit finished();
 	}

shared/indexer.h

@@ -51,21 +51,25 @@ class Indexer : public QObject
 
 	QVector<QString> pathsToScan;
 	QSharedPointer<ParallelDirScanner> dirScanner;
-	QSharedPointer<FileScanWorker> fileScanner;
 
 	QStringList ignorePattern;
 
 	/* Those path pointing to files not directories */
 	ConcurrentQueue<QString> filePathTargetsQueue;
 
+	std::atomic<bool> workerCancellationToken;
 	IndexResult currentIndexResult;
 	void launchWorker(ConcurrentQueue<QString> &queue, int batchsize);
 
   public:
+	bool isRunning();
+
 	void beginIndexing();
 	void setIgnorePattern(QStringList ignorePattern);
 	void setTargetPaths(QVector<QString> pathsToScan);
 
+	void requestCancellation();
+
 	Indexer(SqliteDbService &db);
 	IndexResult getResult();
 

shared/paralleldirscanner.cpp

@@ -31,13 +31,14 @@ void ParallelDirScanner::setPaths(QVector<QString> paths)
 
 void ParallelDirScanner::cancel()
 {
-	this->stopToken.store(true, std::memory_order_relaxed);
+	this->stopToken.store(true, std::memory_order_seq_cst);
 }
 
 void ParallelDirScanner::handleWorkersProgress(unsigned int progress)
 {
 	this->processedPaths += progress;
-	emit this->progress(progress, this->processedPaths);
+	if(!this->stopToken.load(std::memory_order_seq_cst))
+		emit this->progress(progress, this->processedPaths);
 }
 
 void ParallelDirScanner::handleWorkersFinish()
@@ -45,7 +46,7 @@ void ParallelDirScanner::handleWorkersFinish()
 	Logger::info() << "Worker finished";
 	// no mutexes required due to queued connection
 	++finishedWorkers;
-	if(finishedWorkers == getThreadsNum())
+	if(this->stopToken.load(std::memory_order_seq_cst) || finishedWorkers == getThreadsNum())
 	{
 		running = false;
 		emit scanComplete();