Enter MonitoredZimFileInfo::ZimFileStatus

At this point the new enum serves mainly for separating logging
from the logic. But it enables to enhance the logic with more
elaborate handling.

src/contentmanager.cpp

@@ -906,27 +906,49 @@ size_t ContentManager::handleNewZimFiles(const QString& dirPath, const QStringSe
 {
     size_t countOfSuccessfullyAddedZims = 0;
     for (const auto& file : fileNames) {
-        const bool addedToLib = handleZimFileInMonitoredDir(dirPath, file);
+        const bool addedToLib = handleZimFileInMonitoredDirLogged(dirPath, file);
         countOfSuccessfullyAddedZims += addedToLib;
     }
     return countOfSuccessfullyAddedZims;
 }
 
+namespace
+{
+
+#ifndef QT_NO_DEBUG
+
+// indexed by MonitoredZimFileInfo::ZimFileStatus enum
+const char* monitoredDirZimFileHandlingMsgs[] = {
+    "it is being downloaded by us, ignoring...",
+    "the file was added to the library",
+    "the file could not be added to the library"
+};
+
+#endif
+
+} // unnamed namespace
+
+bool ContentManager::handleZimFileInMonitoredDirLogged(QString dir, QString fileName)
+{
+    DBGOUT("ContentManager::handleZimFileInMonitoredDir(" << dir << ", " << fileName << ")");
+    const int status = handleZimFileInMonitoredDir(dir, fileName);
+    DBGOUT("\t" << monitoredDirZimFileHandlingMsgs[status]);
+    return status == MonitoredZimFileInfo::ADDED_TO_THE_LIBRARY;
+}
+
 int ContentManager::handleZimFileInMonitoredDir(QString dir, QString fileName)
 {
     const auto bookPath = QDir::toNativeSeparators(dir + "/" + fileName);
     kiwix::Manager manager(mp_library->getKiwixLibrary());
-    DBGOUT("directory monitoring: file appeared: " << bookPath);
+
     if ( mp_library->isBeingDownloadedByUs(bookPath) ) {
-        DBGOUT("                      it is being downloaded by us, ignoring...");
+        return MonitoredZimFileInfo::BEING_DOWNLOADED_BY_US;
     } else if ( manager.addBookFromPath(bookPath.toStdString()) ) {
-        DBGOUT("                      and was added to the library");
         m_knownZimsInDir[dir].insert(fileName);
-        return 1;
+        return MonitoredZimFileInfo::ADDED_TO_THE_LIBRARY;
     } else {
-        DBGOUT("                      but could not be added to the library");
+        return MonitoredZimFileInfo::COULD_NOT_BE_ADDED_TO_THE_LIBRARY;
     }
-    return 0;
 }
 
 void ContentManager::updateLibraryFromDir(QString dirPath)

src/contentmanager.h

@@ -108,6 +108,22 @@ public slots:
     void downloadWasCancelled(const QString& id);
     void handleError(QString errSummary, QString errDetails);
 
+private: // types
+    struct MonitoredZimFileInfo
+    {
+        enum ZimFileStatus
+        {
+            // the file is known to be downloaded by our own download manager
+            BEING_DOWNLOADED_BY_US,
+
+            // the file was added the library successfully
+            ADDED_TO_THE_LIBRARY,
+
+            // the attempt to add the file to the library failed
+            COULD_NOT_BE_ADDED_TO_THE_LIBRARY
+        };
+    };
+
 private: // functions
     QStringList getBookIds();
     // reallyEraseBook() doesn't ask for confirmation (unlike eraseBook())
@@ -120,6 +136,7 @@ private: // functions
     void updateLibraryFromDir(QString dir);
     void handleDisappearedZimFiles(const QString& dirPath, const QStringSet& fileNames);
     size_t handleNewZimFiles(const QString& dirPath, const QStringSet& fileNames);
+    bool handleZimFileInMonitoredDirLogged(QString dirPath, QString fileName);
     int handleZimFileInMonitoredDir(QString dirPath, QString fileName);
     bool handleDisappearedBook(QString bookId);