Enter ContentManager::BookState

src/contentmanager.cpp

@@ -390,6 +390,19 @@ QVariant getBookAttribute(const kiwix::Book& b, const QString& a)
     return QVariant();
 }
 
+ContentManager::BookState getStateOfLocalBook(const kiwix::Book& book)
+{
+    if ( !book.isPathValid() ) {
+        return ContentManager::BookState::ERROR_MISSING_ZIM_FILE;
+    }
+
+    // XXX: When a book is detected to be corrupted, information about that
+    // XXX: has to be recorded somewhere so that we can return
+    // XXX: ERROR_CORRUPTED_ZIM_FILE here
+
+    return ContentManager::BookState::AVAILABLE_LOCALLY_AND_HEALTHY;
+}
+
 } // unnamed namespace
 
 ContentManager::BookInfo ContentManager::getBookInfos(QString id, const QStringList &keys)
@@ -420,17 +433,40 @@ ContentManager::BookInfo ContentManager::getBookInfos(QString id, const QStringL
     return values;
 }
 
+ContentManager::BookState ContentManager::getBookState(QString bookId)
+{
+    if ( const auto downloadState = m_downloads.value(bookId) ) {
+        return downloadState->paused
+             ? BookState::DOWNLOAD_PAUSED
+             : BookState::DOWNLOADING;
+             // TODO: a download may be in error state
+    }
+
+    try {
+        const kiwix::Book& b = mp_library->getBookById(bookId);
+        return b.getDownloadId().empty()
+             ? getStateOfLocalBook(b)
+             : BookState::DOWNLOADING;
+    } catch (...) {}
+
+    try {
+        QMutexLocker locker(&remoteLibraryLocker);
+        const kiwix::Book& b = mp_remoteLibrary->getBookById(bookId.toStdString());
+        return !b.getUrl().empty()
+             ? BookState::AVAILABLE_ONLINE
+             : BookState::METADATA_ONLY;
+    } catch (...) {}
+
+    return BookState::INVALID;
+}
+
 void ContentManager::openBookWithIndex(const QModelIndex &index)
 {
-    try {
-        auto bookNode = static_cast<Node*>(index.internalPointer());
-        const QString bookId = bookNode->getBookId();
-        // throws std::out_of_range if the book isn't available in local library
-        const kiwix::Book& book = mp_library->getBookById(bookId);
-        if ( !book.getDownloadId().empty() )
-            return;
+    auto bookNode = static_cast<Node*>(index.internalPointer());
+    const QString bookId = bookNode->getBookId();
+    if ( getBookState(bookId) == BookState::AVAILABLE_LOCALLY_AND_HEALTHY ) {
         openBook(bookId);
-    } catch (std::out_of_range &e) {}
+    }
 }
 
 void ContentManager::openBook(const QString &id)

src/contentmanager.h

@@ -20,6 +20,43 @@ public: // types
     typedef ContentManagerModel::BookInfo     BookInfo;
     typedef ContentManagerModel::BookInfoList BookInfoList;
 
+    enum class BookState
+    {
+        // Nothing known about a book with that id
+        INVALID,
+
+        // Only (some) metadata is available for the book, however neither a
+        // ZIM-file nor a URL is associated with it.
+        METADATA_ONLY,
+
+        // No ZIM file is associated with the book but a URL is provided.
+        AVAILABLE_ONLINE,
+
+        // The book is being downloaded.
+        DOWNLOADING,
+
+        // The book started downloading, but the download is currently paused.
+        DOWNLOAD_PAUSED,
+
+        // The book started downloading but the download was stopped due to
+        // errors.
+        DOWNLOAD_ERROR,
+
+        // A valid ZIM file path is associated with the book and no evidence
+        // about any issues with that ZIM file has so far been obtained.
+        AVAILABLE_LOCALLY_AND_HEALTHY,
+
+        // A ZIM file path is associated with the book but no such file seems
+        // to exist (may be caused by missing read permissions for the directory
+        // containing the ZIM file).
+        ERROR_MISSING_ZIM_FILE,
+
+        // A ZIM file is associated with the book but it cannot be opened
+        // due to issues with its content.
+        ERROR_CORRUPTED_ZIM_FILE
+    };
+
+
 public: // functions
     explicit ContentManager(Library* library, kiwix::Downloader *downloader, QObject *parent = nullptr);
     virtual ~ContentManager();
@@ -49,6 +86,7 @@ signals:
 public slots:
     QStringList getTranslations(const QStringList &keys);
     BookInfo getBookInfos(QString id, const QStringList &keys);
+    BookState getBookState(QString id);
     void openBook(const QString& id);
     void downloadBook(const QString& id);
     void downloadBook(const QString& id, QModelIndex index);