logic: reduce access to filesystem while indexing

* use canonical filepath cache in cxx indexer
* made constructors of FilePath explicit
* use FilePath at more places instead of string
* forward declares FilePath wherever possible

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

@@ -467,7 +467,7 @@ void QtProjectWizzard::sourcePathsJava()
 void QtProjectWizzard::sourcePathsJavaMaven()
 {
 	std::dynamic_pointer_cast<SourceGroupSettingsJava>(m_sourceGroupSettings)->setMavenDependenciesDirectory(
-		"./sourcetrail_dependencies/" + utility::replace(m_projectSettings->getProjectName(), " ", "_") + "/maven"
+		FilePath("./sourcetrail_dependencies/" + utility::replace(m_projectSettings->getProjectName(), " ", "_") + "/maven")
 	);
 
 	QtProjectWizzardWindow* window = createWindowWithSummary(

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

@@ -85,7 +85,7 @@ void QtProjectWizzardContentData::save()
 	if (m_projectName)
 	{
 		m_projectSettings->setProjectName(m_projectName->text().toStdString());
-		m_projectSettings->setProjectFileLocation(m_projectFileLocation->getText().toStdString());
+		m_projectSettings->setProjectFileLocation(FilePath(m_projectFileLocation->getText().toStdString()));
 	}
 
 	if (m_standard)
@@ -239,7 +239,7 @@ void QtProjectWizzardContentDataCDB::save()
 {
 	QtProjectWizzardContentData::save();
 
-	FilePath path = m_buildFilePicker->getText().toStdString();
+	FilePath path(m_buildFilePicker->getText().toStdString());
 	FilePath absPath = m_projectSettings->makePathAbsolute(m_projectSettings->expandPath(path)); // maybe we can use SourceGroupSettings for this... that's where the the cdb path is stored.
 	if (!absPath.exists() || absPath.extension() != ".json")
 	{
@@ -260,7 +260,7 @@ bool QtProjectWizzardContentDataCDB::check()
 		return false;
 	}
 
-	FilePath path = m_buildFilePicker->getText().toStdString();
+	FilePath path(m_buildFilePicker->getText().toStdString());
 	FilePath absPath = m_projectSettings->makePathAbsolute(m_projectSettings->expandPath(path));
 	if (!absPath.exists() || absPath.extension() != ".json")
 	{

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

@@ -115,7 +115,7 @@ void QtProjectWizzardContentPathSourceMaven::save()
 	std::shared_ptr<SourceGroupSettingsJava> javaSettings = std::dynamic_pointer_cast<SourceGroupSettingsJava>(m_settings);
 	if (javaSettings)
 	{
-		javaSettings->setMavenProjectFilePath(m_picker->getText().toStdString());
+		javaSettings->setMavenProjectFilePath(FilePath(m_picker->getText().toStdString()));
 		javaSettings->setShouldIndexMavenTests(m_shouldIndexTests->isChecked());
 	}
 }
@@ -202,6 +202,6 @@ void QtProjectWizzardContentPathDependenciesMaven::save()
 	std::shared_ptr<SourceGroupSettingsJava> javaSettings = std::dynamic_pointer_cast<SourceGroupSettingsJava>(m_settings);
 	if (javaSettings)
 	{
-		javaSettings->setMavenDependenciesDirectory(m_picker->getText().toStdString());
+		javaSettings->setMavenDependenciesDirectory(FilePath(m_picker->getText().toStdString()));
 	}
 }

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

@@ -271,7 +271,7 @@ void QtProjectWizzardContentPreferences::load()
 
 	if (m_mavenPath)
 	{
-		m_mavenPath->setText(QString::fromStdString(appSettings->getMavenPath()));
+		m_mavenPath->setText(QString::fromStdString(appSettings->getMavenPath().str()));
 	}
 }
 
@@ -316,7 +316,7 @@ void QtProjectWizzardContentPreferences::save()
 
 	if (m_mavenPath)
 	{
-		appSettings->setMavenPath(m_mavenPath->getText().toStdString());
+		appSettings->setMavenPath(FilePath(m_mavenPath->getText().toStdString()));
 	}
 }
 

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

@@ -111,7 +111,7 @@ void QtProjectWizzardContentSelect::populate(QGridLayout* layout, int& row)
 		{
 			QToolButton* b = createProjectButton(
 				utility::insertLineBreaksAtBlankSpaces(sourceGroupTypeToProjectSetupString(projectIt.type), 15).c_str(),
-				(ResourcePaths::getGuiPath() + "icon/" + m_projectTypeIconName[projectIt.type] + ".png").c_str()
+				(ResourcePaths::getGuiPath().str() + "icon/" + m_projectTypeIconName[projectIt.type] + ".png").c_str()
 			);
 			b->setProperty("source_group_type", int(projectIt.type));
 			projectButtons->addButton(b);