Propagation of library updates to the embedded kiwix server

src/kiwixapp.cpp

@@ -15,6 +15,51 @@
 #include <thread>
 #include <QMessageBox>
 
+////////////////////////////////////////////////////////////////////////////////
+// KiwixApp::NameMapperProxy
+////////////////////////////////////////////////////////////////////////////////
+
+KiwixApp::NameMapperProxy::NameMapperProxy(kiwix::Library& lib)
+  : library(lib)
+{
+  update();
+}
+
+void KiwixApp::NameMapperProxy::update()
+{
+  const auto newNameMapper = new kiwix::HumanReadableNameMapper(library, false);
+  std::lock_guard<std::mutex> lock(mutex);
+  nameMapper.reset(newNameMapper);
+}
+
+KiwixApp::NameMapperProxy::NameMapperHandle
+KiwixApp::NameMapperProxy::currentNameMapper() const
+{
+  // Return a copy of the handle to the current NameMapper object. It will
+  // ensure that the object survives any call to NameMapperProxy::update()
+  // made before the completion of any pending operation on that object.
+  std::lock_guard<std::mutex> lock(mutex);
+  return nameMapper;
+}
+
+std::string KiwixApp::NameMapperProxy::getNameForId(const std::string& id)
+{
+  // Ensure that the current nameMapper object survives a concurrent call
+  // to NameMapperProxy::update()
+  return currentNameMapper()->getNameForId(id);
+}
+
+std::string KiwixApp::NameMapperProxy::getIdForName(const std::string& name)
+{
+  // Ensure that the current nameMapper object survives a concurrent call
+  // to NameMapperProxy::update()
+  return currentNameMapper()->getIdForName(name);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// KiwixApp
+////////////////////////////////////////////////////////////////////////////////
+
 KiwixApp::KiwixApp(int& argc, char *argv[])
     : QtSingleApplication("kiwix-desktop", argc, argv),
       m_profile(),
@@ -23,7 +68,7 @@ KiwixApp::KiwixApp(int& argc, char *argv[])
       mp_downloader(nullptr),
       mp_manager(nullptr),
       mp_mainWindow(nullptr),
-      m_nameMapper(m_library.getKiwixLibrary(), false),
+      m_nameMapper(m_library.getKiwixLibrary()),
       m_server(&m_library.getKiwixLibrary(), &m_nameMapper)
 {
     try {
@@ -411,6 +456,7 @@ void KiwixApp::postInit() {
             [=](const QString& title) { emit currentTitleChanged(title); });
     connect(mp_tabWidget, &TabBar::libraryPageDisplayed, this, &KiwixApp::disableItemsOnLibraryPage);
     emit(m_library.booksChanged());
+    connect(&m_library, &Library::booksChanged, this, &KiwixApp::updateNameMapper);
     disableItemsOnLibraryPage(true);
 }
 
@@ -422,3 +468,8 @@ void KiwixApp::disableItemsOnLibraryPage(bool libraryDisplayed)
     KiwixApp::instance()->getAction(KiwixApp::ZoomOutAction)->setDisabled(libraryDisplayed);
     KiwixApp::instance()->getAction(KiwixApp::ZoomResetAction)->setDisabled(libraryDisplayed);
 }
+
+void KiwixApp::updateNameMapper()
+{
+  m_nameMapper.update();
+}

src/kiwixapp.h

@@ -18,6 +18,8 @@
 #include <QTranslator>
 #include <kiwix/name_mapper.h>
 
+#include <mutex>
+
 
 class KiwixApp : public QtSingleApplication
 {
@@ -99,11 +101,33 @@ public slots:
     void toggleSideBar(KiwixApp::SideBarType type);
     void printPage();
     void disableItemsOnLibraryPage(bool displayed);
+    void updateNameMapper();
 
 protected:
     void createAction();
     void postInit();
 
+private: // types
+  class NameMapperProxy : public kiwix::NameMapper {
+      typedef std::shared_ptr<kiwix::NameMapper> NameMapperHandle;
+    public:
+      explicit NameMapperProxy(kiwix::Library& library);
+
+      virtual std::string getNameForId(const std::string& id);
+      virtual std::string getIdForName(const std::string& name);
+
+      void update();
+
+    private:
+      NameMapperHandle currentNameMapper() const;
+
+    private:
+      mutable std::mutex mutex;
+      kiwix::Library& library;
+      NameMapperHandle nameMapper;
+  };
+
+
 private:
     QTranslator m_qtTranslator, m_appTranslator;
     SettingsManager m_settingsManager;
@@ -116,7 +140,7 @@ public slots:
     TabBar* mp_tabWidget;
     SideBarType m_currentSideType;
     QErrorMessage* mp_errorDialog;
-    kiwix::HumanReadableNameMapper m_nameMapper;
+    NameMapperProxy m_nameMapper;
     kiwix::Server m_server;
     Translation m_translation;