logic: Use all available cores when setting indexer threads to 0 (issue #342)

CMakeLists.txt

@@ -219,6 +219,7 @@ set_property(
 		"${CMAKE_SOURCE_DIR}/src/lib"
 		"${CMAKE_SOURCE_DIR}/src/external"
 		"${CMAKE_SOURCE_DIR}/src/lib_license"
+		"${CMAKE_SOURCE_DIR}/src/lib_gui"
 		"${CMAKE_BINARY_DIR}/src/lib_license"
 )
 

src/lib/project/Project.cpp

@@ -34,6 +34,7 @@
 #include "utility/scheduling/TaskSetValue.h"
 #include "utility/text/TextAccess.h"
 #include "utility/utility.h"
+#include "utility/utilityApp.h"
 #include "utility/utilityString.h"
 #include "utility/Version.h"
 
@@ -412,7 +413,15 @@ void Project::buildIndex(const std::set<FilePath>& filesToClean, bool fullRefres
 
 	if (indexerCommandList->size() > 0)
 	{
-		const size_t indexerThreadCount = ApplicationSettings::getInstance()->getIndexerThreadCount();
+		int indexerThreadCount = ApplicationSettings::getInstance()->getIndexerThreadCount();
+		if (indexerThreadCount <= 0)
+		{
+			indexerThreadCount = utility::getIdealThreadCount();
+			if (indexerThreadCount <= 0)
+			{
+				indexerThreadCount = 4; // setting to some fallback value
+			}
+		}
 
 		if (indexerThreadCount > 1)
 		{

src/lib/settings/ApplicationSettings.cpp

@@ -228,7 +228,7 @@ bool ApplicationSettings::setIndexingFilePaths(const std::vector<FilePath>& inde
 
 int ApplicationSettings::getIndexerThreadCount() const
 {
-	return getValue<int>("indexing/indexer_thread_count", 4);
+	return getValue<int>("indexing/indexer_thread_count", 0);
 }
 
 void ApplicationSettings::setIndexerThreadCount(const int count)

src/lib_gui/qt/window/project_wizzard/QtProjectWizzardContentPreferences.cpp

@@ -1,5 +1,6 @@
 #include "qt/window/project_wizzard/QtProjectWizzardContentPreferences.h"
 
+#include "qt/utility/utilityQt.h"
 #include "settings/ApplicationSettings.h"
 #include "utility/file/FileSystem.h"
 #include "utility/messaging/type/MessageSwitchColorScheme.h"
@@ -92,7 +93,30 @@ void QtProjectWizzardContentPreferences::populate(QGridLayout* layout, int& row)
 	addTitle("INDEXING", layout, row);
 
 	// indexer threads
-	m_threads = addComboBox("Indexer threads", 1, 24, "Number of parallel threads used to index your projects.", layout, row);
+	const int minThreadCount = 0;
+	const int maxThreadCount = 24;
+
+	m_threads = new QComboBox(this);
+	connect(m_threads, SIGNAL(activated(int)), this, SLOT(indexerThreadsChanges(int)));
+	for (int i = minThreadCount; i <= maxThreadCount; i++)
+	{
+		m_threads->insertItem(i, QString::number(i));
+	}
+
+	m_threadsInfoLabel = new QLabel("");
+	utility::setWidgetRetainsSpaceWhenHidden(m_threadsInfoLabel);
+
+	QHBoxLayout* hlayout = new QHBoxLayout();
+	hlayout->setContentsMargins(0, 0, 0, 0);
+	hlayout->addWidget(m_threads);
+	hlayout->addWidget(m_threadsInfoLabel);
+
+	QWidget* threadsWidget = new QWidget();
+	threadsWidget->setLayout(hlayout);
+
+	addLabelAndWidget("Indexer threads", threadsWidget, layout, row, Qt::AlignLeft);
+	addHelpButton("Number of parallel threads used to index your projects.\nWhen setting this to 0 Sourcetrail tries to use the ideal thread count for your computer.", layout, row);
+	row++;
 
 	addGap(layout, row);
 
@@ -230,7 +254,8 @@ void QtProjectWizzardContentPreferences::load()
 	m_sourcetrailPort->setText(QString::number(appSettings->getSourcetrailPort()));
 	m_pluginPort->setText(QString::number(appSettings->getPluginPort()));
 
-	m_threads->setCurrentIndex(appSettings->getIndexerThreadCount() - 1);
+	m_threads->setCurrentIndex(appSettings->getIndexerThreadCount()); // index and value are the same
+	indexerThreadsChanges(m_threads->currentIndex());
 
 	if (m_javaPath)
 	{
@@ -273,7 +298,7 @@ void QtProjectWizzardContentPreferences::save()
 	int pluginPort = m_pluginPort->text().toInt();
 	if (pluginPort) appSettings->setPluginPort(pluginPort);
 
-	appSettings->setIndexerThreadCount(m_threads->currentIndex() + 1);
+	appSettings->setIndexerThreadCount(m_threads->currentIndex()); // index and value are the same
 
 	if (m_javaPath)
 	{
@@ -323,6 +348,19 @@ void QtProjectWizzardContentPreferences::loggingEnabledChanged()
 	m_verboseIndexerLoggingEnabled->setEnabled(m_loggingEnabled->isChecked());
 }
 
+void QtProjectWizzardContentPreferences::indexerThreadsChanges(int index)
+{
+	if (index == 0)
+	{
+		m_threadsInfoLabel->setText(("detected " + std::to_string(utility::getIdealThreadCount()) + " threads to be ideal.").c_str());
+		m_threadsInfoLabel->show();
+	}
+	else
+	{
+		m_threadsInfoLabel->hide();
+	}
+}
+
 void QtProjectWizzardContentPreferences::addJavaPathDetection(QGridLayout* layout, int& row)
 {
 	std::vector<std::string> detectorNames = m_javaPathDetector->getWorkingDetectorNames();

src/lib_gui/qt/window/project_wizzard/QtProjectWizzardContentPreferences.h

@@ -3,6 +3,7 @@
 
 #include <QCheckBox>
 #include <QComboBox>
+#include <QLabel>
 #include <QLineEdit>
 
 #include "qt/element/QtFontPicker.h"
@@ -31,6 +32,7 @@ private slots:
 	void javaPathDetectionClicked();
 	void mavenPathDetectionClicked();
 	void loggingEnabledChanged();
+	void indexerThreadsChanges(int index);
 
 private:
 	void addJavaPathDetection(QGridLayout* layout, int& row);
@@ -65,6 +67,7 @@ private:
 	QLineEdit* m_pluginPort;
 
 	QComboBox* m_threads;
+	QLabel* m_threadsInfoLabel;
 
 	std::shared_ptr<CombinedPathDetector> m_javaPathDetector;
 	std::shared_ptr<CombinedPathDetector> m_mavenPathDetector;

src/lib_gui/utility/utilityApp.cpp

@@ -1,6 +1,7 @@
 #include "utility/utilityApp.h"
 
 #include <QProcess>
+#include <QThread>
 #include <qprocessordetection.h>
 
 #include "utility/utilityString.h"
@@ -35,3 +36,8 @@ ApplicationArchitectureType utility::getApplicationArchitectureType()
 #endif
 	return APPLICATION_ARCHITECTURE_UNKNOWN;
 }
+
+int utility::getIdealThreadCount()
+{
+	return QThread::idealThreadCount();
+}

src/lib_gui/utility/utilityApp.h

@@ -10,6 +10,8 @@ namespace utility
 	std::string executeProcess(const std::string& command, const std::string& workingDirectory = "");
 
 	ApplicationArchitectureType getApplicationArchitectureType();
+
+	int getIdealThreadCount();
 }
 
 #endif // UTILITY_APP_H