generator.h

/*
    SPDX-FileCopyrightText: 2004-5 Enrico Ros <eros.kde@email.it>
    SPDX-FileCopyrightText: 2005 Piotr Szymanski <niedakh@gmail.com>
    SPDX-FileCopyrightText: 2008 Albert Astals Cid <aacid@kde.org>
 
    Work sponsored by the LiMux project of the city of Munich:
    SPDX-FileCopyrightText: 2017 Klarälvdalens Datakonsult AB a KDAB Group company <info@kdab.com>
 
    SPDX-License-Identifier: GPL-2.0-or-later
*/
 
#ifndef _OKULAR_GENERATOR_H_
#define _OKULAR_GENERATOR_H_
 
#include "action.h"
#include "document.h"
#include "fontinfo.h"
#include "global.h"
#include "okularcore_export.h"
#include "pagesize.h"
#include "signatureutils.h"
 
#include <QList>
#include <QObject>
#include <QSharedDataPointer>
#include <QSizeF>
#include <QString>
#include <QVariant>
#include <QVector>
 
#include <KPluginFactory>
#include <QMimeType>
 
#define OKULAR_EXPORT_PLUGIN(classname, json)                                                                                                                                                                                                  \
    static_assert(json[0] != '\0', "arg2 must be a string literal");                                                                                                                                                                           \
    K_PLUGIN_CLASS_WITH_JSON(classname, json)
 
class QByteArray;
class QMutex;
class QPrinter;
class QIcon;
 
namespace Okular
{
class BackendOpaqueAction;
class DocumentFonts;
class DocumentInfo;
class DocumentObserver;
class DocumentSynopsis;
class EmbeddedFile;
class ExportFormatPrivate;
class FontInfo;
class GeneratorPrivate;
class Page;
class PixmapRequest;
class PixmapRequestPrivate;
class TextPage;
class TextRequest;
class TextRequestPrivate;
class NormalizedRect;
 
/* Note: on contents generation and asynchronous queries.
 * Many observers may want to request data synchronously or asynchronously.
 * - Sync requests. These should be done in-place.
 * - Async request must be done in real background. That usually means a
 *   thread, such as QThread derived classes.
 * Once contents are available, they must be immediately stored in the
 * Page they refer to, and a signal is emitted as soon as storing
 * (even for sync or async queries) has been done.
 */
 
/**
 * @short Defines an entry for the export menu
 *
 * This class encapsulates information about an export format.
 * Every Generator can support 0 or more export formats which can be
 * queried with @ref Generator::exportFormats().
 */
class OKULARCORE_EXPORT ExportFormat
{
public:
    typedef QList<ExportFormat> List;
 
    /**
     * Creates an empty export format.
     *
     * @see isNull()
     */
    ExportFormat();
 
    /**
     * Creates a new export format.
     *
     * @param description The i18n'ed description of the format.
     * @param mimeType The supported mime type of the format.
     */
    ExportFormat(const QString &description, const QMimeType &mimeType);
 
    /**
     * Creates a new export format.
     *
     * @param icon The icon used in the GUI for this format.
     * @param description The i18n'ed description of the format.
     * @param mimeType The supported mime type of the format.
     */
    ExportFormat(const QIcon &icon, const QString &description, const QMimeType &mimeType);
 
    /**
     * Destroys the export format.
     */
    ~ExportFormat();
 
    /**
     * @internal
     */
    ExportFormat(const ExportFormat &other);
 
    /**
     * @internal
     */
    ExportFormat &operator=(const ExportFormat &other);
 
    /**
     * Returns the description of the format.
     */
    QString description() const;
 
    /**
     * Returns the mime type of the format.
     */
    QMimeType mimeType() const;
 
    /**
     * Returns the icon for GUI representations of the format.
     */
    QIcon icon() const;
 
    /**
     * Returns whether the export format is null/valid.
     *
     * An ExportFormat is null if the mimetype is not valid or the
     * description is empty, or both.
     */
    bool isNull() const;
 
    /**
     * Type of standard export format.
     */
    enum StandardExportFormat {
        PlainText,        ///< Plain text
        PDF,              ///< PDF, aka Portable Document Format
        OpenDocumentText, ///< OpenDocument Text format @since 0.8 (KDE 4.2)
        HTML              ///< OpenDocument Text format @since 0.8 (KDE 4.2)
    };
 
    /**
     * Builds a standard format for the specified @p type .
     */
    static ExportFormat standardFormat(StandardExportFormat type);
 
    bool operator==(const ExportFormat &other) const;
 
    bool operator!=(const ExportFormat &other) const;
 
private:
    /// @cond PRIVATE
    friend class ExportFormatPrivate;
    /// @endcond
    QSharedDataPointer<ExportFormatPrivate> d;
};
 
/**
 * @short [Abstract Class] The information generator.
 *
 * Most of class members are virtuals and some of them pure virtual. The pure
 * virtuals provide the minimal functionalities for a Generator, that is being
 * able to generate QPixmap for the Page 's of the Document.
 *
 * Implementing the other functions will make the Generator able to provide
 * more contents and/or functionalities (like text extraction).
 *
 * Generation/query is requested by the Document class only, and that
 * class stores the resulting data into Page s. The data will then be
 * displayed by the GUI components (PageView, ThumbnailList, etc..).
 *
 * @see PrintInterface, ConfigInterface, GuiInterface
 */
class OKULARCORE_EXPORT Generator : public QObject
{
    /// @cond PRIVATE
    friend class PixmapGenerationThread;
    friend class TextPageGenerationThread;
    /// @endcond
 
    Q_OBJECT
 
public:
    /**
     * Describe the possible optional features that a Generator can
     * provide.
     */
    enum GeneratorFeature {
        Threaded,          ///< Whether the Generator supports asynchronous generation of pictures or text pages
        TextExtraction,    ///< Whether the Generator can extract text from the document in the form of TextPage's
        ReadRawData,       ///< Whether the Generator can read a document directly from its raw data.
        FontInfo,          ///< Whether the Generator can provide information about the fonts used in the document
        PageSizes,         ///< Whether the Generator can change the size of the document pages.
        PrintNative,       ///< Whether the Generator supports native cross-platform printing (QPainter-based).
        PrintPostscript,   ///< Whether the Generator supports postscript-based file printing.
        PrintToFile,       ///< Whether the Generator supports export to PDF & PS through the Print Dialog
        TiledRendering,    ///< Whether the Generator can render tiles @since 0.16 (KDE 4.10)
        SwapBackingFile,   ///< Whether the Generator can hot-swap the file it's reading from @since 1.3
        SupportsCancelling ///< Whether the Generator can cancel requests @since 1.4
    };
 
    /**
     * Creates a new generator.
     */
    explicit Generator(QObject *parent = nullptr, const QVariantList &args = QVariantList());
 
    /**
     * Destroys the generator.
     */
    ~Generator() override;
 
    /**
     * Loads the document with the given @p fileName and fills the
     * @p pagesVector with the parsed pages.
     *
     * @note If you implement the WithPassword variants you don't need to implement this one
     *
     * @returns true on success, false otherwise.
     */
    virtual bool loadDocument(const QString &fileName, QVector<Page *> &pagesVector);
 
    /**
     * Loads the document from the raw data @p fileData and fills the
     * @p pagesVector with the parsed pages.
     *
     * @note If you implement the WithPassword variants you don't need to implement this one
     *
     * @note the Generator has to have the feature @ref ReadRawData enabled
     *
     * @returns true on success, false otherwise.
     */
    virtual bool loadDocumentFromData(const QByteArray &fileData, QVector<Page *> &pagesVector);
 
    /**
     * Loads the document with the given @p fileName and @p password and fills the
     * @p pagesVector with the parsed pages.
     *
     * @note Do not implement this if your format doesn't support passwords, it'll cleanly call loadDocument()
     *
     * @since 0.20 (KDE 4.14)
     *
     * @returns a LoadResult defining the result of the operation
     */
    virtual Document::OpenResult loadDocumentWithPassword(const QString &fileName, QVector<Page *> &pagesVector, const QString &password);
 
    /**
     * Loads the document from the raw data @p fileData and @p password and fills the
     * @p pagesVector with the parsed pages.
     *
     * @note Do not implement this if your format doesn't support passwords, it'll cleanly call loadDocumentFromData()
     *
     * @note the Generator has to have the feature @ref ReadRawData enabled
     *
     * @since 0.20 (KDE 4.14)
     *
     * @returns a LoadResult defining the result of the operation
     */
    virtual Document::OpenResult loadDocumentFromDataWithPassword(const QByteArray &fileData, QVector<Page *> &pagesVector, const QString &password);
 
    /**
     * Describes the result of an swap file operation.
     *
     * @since 1.3
     */
    enum SwapBackingFileResult {
        SwapBackingFileError,             //< The document could not be swapped
        SwapBackingFileNoOp,              //< The document was swapped and nothing needs to be done
        SwapBackingFileReloadInternalData //< The document was swapped and internal data (forms, annotations, etc) needs to be reloaded
    };
 
    /**
     * Changes the path of the file we are reading from. The new path must
     * point to a copy of the same document.
     *
     * @note the Generator has to have the feature @ref SwapBackingFile enabled
     *
     * @since 1.3
     */
    virtual SwapBackingFileResult swapBackingFile(const QString &newFileName, QVector<Okular::Page *> &newPagesVector);
 
    /**
     * This method is called when the document is closed and not used
     * any longer.
     *
     * @returns true on success, false otherwise.
     */
    bool closeDocument();
 
    /**
     * This method returns whether the generator is ready to
     * handle a new pixmap request.
     */
    virtual bool canGeneratePixmap() const;
 
    virtual bool canSign() const;
 
    virtual bool sign(const NewSignatureData &data, const QString &rFilename);
 
    virtual CertificateStore *certificateStore() const;
 
    /**
     * This method can be called to trigger the generation of
     * a new pixmap as described by @p request.
     */
    virtual void generatePixmap(PixmapRequest *request);
 
    /**
     * This method returns whether the generator is ready to
     * handle a new text page request.
     */
    virtual bool canGenerateTextPage() const;
 
    /**
     * This method can be called to trigger the generation of
     * a text page for the given @p page.
     *
     * The generation is done in the calling thread.
     *
     * @see TextPage
     */
    void generateTextPage(Page *page);
 
    /**
     * Returns the general information object of the document.
     *
     * Changed signature in okular version 0.21
     */
    virtual DocumentInfo generateDocumentInfo(const QSet<DocumentInfo::Key> &keys) const;
 
    /**
     * Returns the 'table of content' object of the document or 0 if
     * no table of content is available.
     */
    virtual const DocumentSynopsis *generateDocumentSynopsis();
 
    /**
     * Returns the 'list of embedded fonts' object of the specified \p page
     * of the document.
     *
     * \param page a page of the document, starting from 0 - -1 indicates all
     * the other fonts
     */
    virtual FontInfo::List fontsForPage(int page);
 
    /**
     * Returns the 'list of embedded files' object of the document or 0 if
     * no list of embedded files is available.
     */
    virtual const QList<EmbeddedFile *> *embeddedFiles() const;
 
    /**
     * This enum identifies default page layouts.
     *
     * @since 24.12
     */
    enum PageLayout {
        NoLayout = -1, ///< Layout not specified
        SinglePage,    ///< Display a single page
        TwoPageLeft,   ///< Display the pages in two columns, with odd-numbered pages on the left
        TwoPageRight   ///< Display the pages in two columns, with odd-numbered pages on the right
    };
 
    /**
     * This method returns the default page layout.
     *
     * @since 24.12
     */
    virtual PageLayout defaultPageLayout() const;
 
    /**
     * This method returns if the default page layout is continuous.
     *
     * @since 24.12
     */
    virtual bool defaultPageContinuous() const;
 
    /**
     * This enum identifies the metric of the page size.
     */
    enum PageSizeMetric {
        None,   ///< The page size is not defined in a physical metric.
        Points, ///< The page size is given in 1/72 inches.
        Pixels  ///< The page size is given in screen pixels @since 0.19 (KDE 4.13)
    };
 
    /**
     * This method returns the metric of the page size. Default is @ref None.
     */
    virtual PageSizeMetric pagesSizeMetric() const;
 
    /**
     * Returns whether the given @p action is allowed in the document.
     * @see @ref Okular::Permission
     */
    virtual bool isAllowed(Permission action) const;
 
    /**
     * This method is called when the orientation has been changed by the user.
     */
    virtual void rotationChanged(Rotation orientation, Rotation oldOrientation);
 
    /**
     * Returns the list of supported page sizes.
     */
    virtual PageSize::List pageSizes() const;
 
    /**
     * This method is called when the page size has been changed by the user.
     */
    virtual void pageSizeChanged(const PageSize &pageSize, const PageSize &oldPageSize);
 
    /**
     * This method is called to print the document to the given @p printer.
     */
    virtual Document::PrintError print(QPrinter &printer);
 
    /**
     * This method returns the meta data of the given @p key with the given @p option
     * of the document.
     */
    virtual QVariant metaData(const QString &key, const QVariant &option) const;
 
    /**
     * Returns the list of additional supported export formats.
     */
    virtual ExportFormat::List exportFormats() const;
 
    /**
     * This method is called to export the document in the given @p format and save it
     * under the given @p fileName. The format must be one of the supported export formats.
     */
    virtual bool exportTo(const QString &fileName, const ExportFormat &format);
 
    /**
     * This method is called to know which wallet data should be used for the given file name.
     * Unless you have very special requirements to where wallet data should be stored you
     * don't need to reimplement this method.
     */
    virtual void walletDataForFile(const QString &fileName, QString *walletName, QString *walletFolder, QString *walletKey) const;
 
    /**
     * Query for the specified @p feature.
     */
    bool hasFeature(GeneratorFeature feature) const;
 
    /**
     * Update DPI of the generator
     *
     * @since 0.19 (old signature)
     * @since 22.04 (new signature)
     */
    void setDPI(const QSizeF dpi);
 
    /**
     * Returns the 'layers model' object of the document or NULL if
     * layers model is not available.
     *
     * @since 0.24
     */
    virtual QAbstractItemModel *layersModel() const;
 
    /**
     * Calls the backend to execute a BackendOpaqueAction @p action and returns BackendOpaqueAction result
     */
    virtual BackendOpaqueAction::OpaqueActionResult opaqueAction(const BackendOpaqueAction *action);
 
    /**
     * Frees the contents of the opaque action (if any);
     *
     * @since 22.04
     */
    virtual void freeOpaqueActionContents(const BackendOpaqueAction &action);
 
    /**
     * Retrieves the additional document action for the specified @p type .
     *
     * @since 24.08
     */
    virtual Okular::Action *additionalDocumentAction(Document::DocumentAdditionalActionType type);
 
Q_SIGNALS:
    /**
     * This signal should be emitted whenever an error occurred in the generator.
     *
     * @param message The message which should be shown to the user.
     * @param duration The time that the message should be shown to the user.
     */
    void error(const QString &message, int duration);
 
    /**
     * This signal should be emitted whenever the user should be warned.
     *
     * @param message The message which should be shown to the user.
     * @param duration The time that the message should be shown to the user.
     */
    void warning(const QString &message, int duration);
 
    /**
     * This signal should be emitted whenever the user should be noticed.
     *
     * @param message The message which should be shown to the user.
     * @param duration The time that the message should be shown to the user.
     */
    void notice(const QString &message, int duration);
 
protected:
    /**
     * This method must be called when the pixmap request triggered by generatePixmap()
     * has been finished.
     */
    void signalPixmapRequestDone(PixmapRequest *request);
 
    /**
     * This method must be called when a text generation has been finished.
     */
    void signalTextGenerationDone(Page *page, TextPage *textPage);
 
    /**
     * This method is called when the document is closed and not used
     * any longer.
     *
     * @returns true on success, false otherwise.
     */
    virtual bool doCloseDocument() = 0;
 
    /**
     * Returns the image of the page as specified in
     * the passed pixmap @p request.
     *
     * Must return a null image if the request was cancelled and the generator supports cancelling
     *
     * @warning this method may be executed in its own separated thread if the
     * @ref Threaded is enabled!
     */
    virtual QImage image(PixmapRequest *request);
 
    /**
     * Returns the text page for the given @p request.
     *
     * Must return a null pointer if the request was cancelled and the generator supports cancelling
     *
     * @warning this method may be executed in its own separated thread if the
     * @ref Threaded is enabled!
     *
     * @since 1.4
     */
    virtual TextPage *textPage(TextRequest *request);
 
    /**
     * Returns a pointer to the document.
     */
    const Document *document() const;
 
    /**
     * Toggle the @p feature .
     */
    void setFeature(GeneratorFeature feature, bool on = true);
 
    /**
     * Internal document setting
     */
    enum DocumentMetaDataKey {
        PaperColorMetaData,        ///< Returns (QColor) the paper color if set in Settings or the default color (white) if option is true (otherwise returns a non initialized QColor)
        TextAntialiasMetaData,     ///< Returns (bool) text antialias from Settings (option is not used)
        GraphicsAntialiasMetaData, ///< Returns (bool)graphic antialias from Settings (option is not used)
        TextHintingMetaData        ///< Returns (bool)text hinting from Settings (option is not used)
    };
 
    /**
     * Request a meta data of the Document, if available, like an internal
     * setting.
     *
     * @since 1.1
     */
    QVariant documentMetaData(const DocumentMetaDataKey key, const QVariant &option = QVariant()) const;
 
    /**
     * Return the pointer to a mutex the generator can use freely.
     */
    QMutex *userMutex() const;
 
    /**
     * Set the bounding box of a page after the page has already been handed
     * to the Document. Call this instead of Page::setBoundingBox() to ensure
     * that all observers are notified.
     *
     * @since 0.7 (KDE 4.1)
     */
    void updatePageBoundingBox(int page, const NormalizedRect &boundingBox);
 
    /**
     * Returns DPI, previously set via setDPI()
     * @since 0.19 (KDE 4.13)
     */
    QSizeF dpi() const;
 
    /**
     * Gets the font data for the given font
     *
     * @since 0.8 (old signature)
     * @since 22.04 (new signature)
     */
    virtual QByteArray requestFontData(const Okular::FontInfo &font);
 
protected Q_SLOTS:
    /**
     * This method can be called to trigger a partial pixmap update for the given request
     * Make sure you call it in a way it's executed in the main thread.
     * @since 1.3
     */
    void signalPartialPixmapRequest(Okular::PixmapRequest *request, const QImage &image);
 
protected:
    /// @cond PRIVATE
    Generator(GeneratorPrivate &dd, QObject *parent, const QVariantList &args);
    Q_DECLARE_PRIVATE(Generator)
    GeneratorPrivate *d_ptr;
 
    friend class Document;
    friend class DocumentPrivate;
    /// @endcond PRIVATE
 
private:
    Q_DISABLE_COPY(Generator)
};
 
/**
 * @short Describes a pixmap type request.
 */
class OKULARCORE_EXPORT PixmapRequest
{
    friend class Document;
    friend class DocumentPrivate;
 
public:
    enum PixmapRequestFeature { NoFeature = 0, Asynchronous = 1, Preload = 2 };
    Q_DECLARE_FLAGS(PixmapRequestFeatures, PixmapRequestFeature)
 
    /**
     * Creates a new pixmap request.
     *
     * @param observer The observer.
     * @param pageNumber The page number.
     * @param width The width of the page in logical pixels.
     * @param height The height of the page in logical pixels.
     * @param dpr Device pixel ratio of the screen that the pixmap is intended for.
     * @param priority The priority of the request.
     * @param features The features of generation.
     */
    PixmapRequest(DocumentObserver *observer, int pageNumber, int width, int height, qreal dpr, int priority, PixmapRequestFeatures features);
 
    /**
     * Destroys the pixmap request.
     */
    ~PixmapRequest();
 
    /**
     * Returns the observer of the request.
     */
    DocumentObserver *observer() const;
 
    /**
     * Returns the page number of the request.
     */
    int pageNumber() const;
 
    /**
     * Returns the page width of the requested pixmap.
     */
    int width() const;
 
    /**
     * Returns the page height of the requested pixmap.
     */
    int height() const;
 
    /**
     * Returns the priority (less it better, 0 is maximum) of the
     * request.
     */
    int priority() const;
 
    /**
     * Returns whether the generation should be done synchronous or
     * asynchronous.
     *
     * If asynchronous, the pixmap is created in a thread and the observer
     * is notified when the job is done.
     */
    bool asynchronous() const;
 
    /**
     * Returns whether the generation request is for a page that is not important
     * i.e. it's just for speeding up future rendering
     */
    bool preload() const;
 
    /**
     * Returns a pointer to the page where the pixmap shall be generated for.
     */
    Page *page() const;
 
    /**
     * Sets whether the generator should render only the given normalized
     * rect or the entire page
     *
     * @since 0.16 (KDE 4.10)
     */
    void setTile(bool tile);
 
    /**
     * Returns whether the generator should render just the region given by
     * normalizedRect() or the entire page.
     *
     * @since 0.16 (KDE 4.10)
     */
    bool isTile() const;
 
    /**
     * Sets the region of the page to request.
     *
     * @since 0.16 (KDE 4.10)
     */
    void setNormalizedRect(const NormalizedRect &rect);
 
    /**
     * Returns the normalized region of the page to request.
     *
     * @since 0.16 (KDE 4.10)
     */
    const NormalizedRect &normalizedRect() const;
 
    /**
     * Sets whether the request should report back updates if possible
     *
     * @since 1.3
     */
    void setPartialUpdatesWanted(bool partialUpdatesWanted);
 
    /**
     * Should the request report back updates if possible?
     *
     * @since 1.3
     */
    bool partialUpdatesWanted() const;
 
    /**
     * Should the request be aborted if possible?
     *
     * @since 1.4
     */
    bool shouldAbortRender() const;
 
private:
    Q_DISABLE_COPY(PixmapRequest)
 
    friend class PixmapRequestPrivate;
    PixmapRequestPrivate *const d;
};
 
/**
 * @short Describes a text request.
 *
 * @since 1.4
 */
class OKULARCORE_EXPORT TextRequest
{
public:
    /**
     * Creates a new text request.
     */
    explicit TextRequest(Page *page);
 
    TextRequest();
 
    /**
     * Destroys the pixmap request.
     */
    ~TextRequest();
 
    /**
     * Returns a pointer to the page where the pixmap shall be generated for.
     */
    Page *page() const;
 
    /**
     * Should the request be aborted if possible?
     */
    bool shouldAbortExtraction() const;
 
private:
    Q_DISABLE_COPY(TextRequest)
 
    friend TextRequestPrivate;
    TextRequestPrivate *const d;
};
 
}
 
Q_DECLARE_METATYPE(Okular::PixmapRequest *)
 
#define OkularGeneratorInterface_iid "org.kde.okular.Generator"
Q_DECLARE_INTERFACE(Okular::Generator, OkularGeneratorInterface_iid)
 
#ifndef QT_NO_DEBUG_STREAM
OKULARCORE_EXPORT QDebug operator<<(QDebug str, const Okular::PixmapRequest &req);
#endif
 
#endif
 
/* kate: replace-tabs on; indent-width 4; */