Unite tool (basics)

PdfForQtLib/sources/pdfdocument.h

@@ -147,7 +147,7 @@ private:
 /// then if object with valid data is not found, default value is used, and second one,
 /// without default value, if valid data are not found, then exception is thrown.
 /// This class uses Decorator design pattern.
-class PDFDocumentDataLoaderDecorator
+class PDFFORQTLIBSHARED_EXPORT PDFDocumentDataLoaderDecorator
 {
 public:
     explicit PDFDocumentDataLoaderDecorator(const PDFDocument* document);

PdfForQtLib/sources/pdfdocumentbuilder.cpp

@@ -752,6 +752,11 @@ void PDFDocumentBuilder::mergeTo(PDFObjectReference reference, PDFObject object)
     m_storage.setObject(reference, PDFObjectManipulator::merge(m_storage.getObject(reference), qMove(object), PDFObjectManipulator::RemoveNullObjects));
 }
 
+void PDFDocumentBuilder::setObject(PDFObjectReference reference, PDFObject object)
+{
+    m_storage.setObject(reference, qMove(object));
+}
+
 void PDFDocumentBuilder::appendTo(PDFObjectReference reference, PDFObject object)
 {
     m_storage.setObject(reference, PDFObjectManipulator::merge(m_storage.getObject(reference), qMove(object), PDFObjectManipulator::ConcatenateArrays));
@@ -1016,6 +1021,20 @@ std::vector<PDFObject> PDFDocumentBuilder::copyFrom(const std::vector<PDFObject>
     return result;
 }
 
+std::vector<PDFObject> PDFDocumentBuilder::createObjectsFromReferences(const std::vector<PDFObjectReference>& references)
+{
+    std::vector<PDFObject> result;
+    std::transform(references.cbegin(), references.cend(), std::back_inserter(result), [](const PDFObjectReference& reference) { return PDFObject::createReference(reference); });
+    return result;
+}
+
+std::vector<PDFObjectReference> PDFDocumentBuilder::createReferencesFromObjects(const std::vector<PDFObject>& objects)
+{
+    std::vector<PDFObjectReference> result;
+    std::transform(objects.cbegin(), objects.cend(), std::back_inserter(result), [](const PDFObject& object) { Q_ASSERT(object.isReference()); return object.getReference(); });
+    return result;
+}
+
 const PDFFormManager* PDFDocumentBuilder::getFormManager() const
 {
     return m_formManager;
@@ -2863,6 +2882,23 @@ PDFObject PDFDocumentBuilder::createTrailerDictionary(PDFObjectReference catalog
 }
 
 
+void PDFDocumentBuilder::removeDocumentActions()
+{
+    PDFObjectFactory objectBuilder;
+
+    objectBuilder.beginDictionary();
+    objectBuilder.beginDictionaryItem("OpenAction");
+    objectBuilder << PDFObject();
+    objectBuilder.endDictionaryItem();
+    objectBuilder.beginDictionaryItem("AA");
+    objectBuilder << PDFObject();
+    objectBuilder.endDictionaryItem();
+    objectBuilder.endDictionary();
+    PDFObject updatedCatalog = objectBuilder.takeObject();
+    mergeTo(getCatalogReference(), updatedCatalog);
+}
+
+
 void PDFDocumentBuilder::removeOutline()
 {
     PDFObjectFactory objectBuilder;
@@ -2877,6 +2913,37 @@ void PDFDocumentBuilder::removeOutline()
 }
 
 
+void PDFDocumentBuilder::removeStructureTree()
+{
+    PDFObjectFactory objectBuilder;
+
+    objectBuilder.beginDictionary();
+    objectBuilder.beginDictionaryItem("StructTreeRoot");
+    objectBuilder << PDFObject();
+    objectBuilder.endDictionaryItem();
+    objectBuilder.beginDictionaryItem("MarkInfo");
+    objectBuilder << PDFObject();
+    objectBuilder.endDictionaryItem();
+    objectBuilder.endDictionary();
+    PDFObject updatedCatalog = objectBuilder.takeObject();
+    mergeTo(getCatalogReference(), updatedCatalog);
+}
+
+
+void PDFDocumentBuilder::removeThreads()
+{
+    PDFObjectFactory objectBuilder;
+
+    objectBuilder.beginDictionary();
+    objectBuilder.beginDictionaryItem("Threads");
+    objectBuilder << PDFObject();
+    objectBuilder.endDictionaryItem();
+    objectBuilder.endDictionary();
+    PDFObject updatedCatalog = objectBuilder.takeObject();
+    mergeTo(getCatalogReference(), updatedCatalog);
+}
+
+
 void PDFDocumentBuilder::setAnnotationAppearanceState(PDFObjectReference annotation,
                                                       QByteArray appearanceState)
 {
@@ -3245,47 +3312,13 @@ void PDFDocumentBuilder::updateTrailerDictionary(PDFInteger objectCount)
 }
 
 
-void PDFDocumentBuilder::removeThreads()
+void PDFDocumentBuilder::setCatalogOptionalContentProperties(PDFObjectReference ocProperties)
 {
     PDFObjectFactory objectBuilder;
 
     objectBuilder.beginDictionary();
-    objectBuilder.beginDictionaryItem("Threads");
+    objectBuilder.beginDictionaryItem("OCProperties");
-    objectBuilder << PDFObject();
+    objectBuilder << ocProperties;
-    objectBuilder.endDictionaryItem();
-    objectBuilder.endDictionary();
-    PDFObject updatedCatalog = objectBuilder.takeObject();
-    mergeTo(getCatalogReference(), updatedCatalog);
-}
-
-
-void PDFDocumentBuilder::removeDocumentActions()
-{
-    PDFObjectFactory objectBuilder;
-
-    objectBuilder.beginDictionary();
-    objectBuilder.beginDictionaryItem("OpenAction");
-    objectBuilder << PDFObject();
-    objectBuilder.endDictionaryItem();
-    objectBuilder.beginDictionaryItem("AA");
-    objectBuilder << PDFObject();
-    objectBuilder.endDictionaryItem();
-    objectBuilder.endDictionary();
-    PDFObject updatedCatalog = objectBuilder.takeObject();
-    mergeTo(getCatalogReference(), updatedCatalog);
-}
-
-
-void PDFDocumentBuilder::removeStructureTree()
-{
-    PDFObjectFactory objectBuilder;
-
-    objectBuilder.beginDictionary();
-    objectBuilder.beginDictionaryItem("StructTreeRoot");
-    objectBuilder << PDFObject();
-    objectBuilder.endDictionaryItem();
-    objectBuilder.beginDictionaryItem("MarkInfo");
-    objectBuilder << PDFObject();
     objectBuilder.endDictionaryItem();
     objectBuilder.endDictionary();
     PDFObject updatedCatalog = objectBuilder.takeObject();

PdfForQtLib/sources/pdfdocumentbuilder.h

@@ -302,6 +302,52 @@ public:
     /// be flattened to use this function. \sa flattenPageTree
     std::vector<PDFObjectReference> getPages() const;
 
+    /// Adds a new objet to the object storage
+    /// \param object Object
+    PDFObjectReference addObject(PDFObject object);
+
+    /// Copies objects from another storage. Objects have adjusted references to match
+    /// this storage references and objects are added after the last objects of active storage.
+    /// This function can also automatically create references from direct objects passed
+    /// by parameter \p objects, if \p createReferences is set to true.
+    /// \param objects Objects, which we want to copy from another storage
+    /// \param storage Storage, from which we are copying from
+    /// \param createReferences Create references from \p objects
+    std::vector<PDFObject> copyFrom(const std::vector<PDFObject>& objects, const PDFObjectStorage& storage, bool createReferences);
+
+    /// Creates object list from reference list (objects are references)
+    /// \param references References
+    static std::vector<PDFObject> createObjectsFromReferences(const std::vector<PDFObjectReference>& references);
+
+    /// Creates reference list from object list. Object list must be
+    /// a list of references, it is invalid to pass this function objects,
+    /// which are not references.
+    /// \param objects Objects with references
+    static std::vector<PDFObjectReference> createReferencesFromObjects(const std::vector<PDFObject>& objects);
+
+    /// Returns catalog reference
+    PDFObjectReference getCatalogReference() const;
+
+    /// Returns object storage
+    const PDFObjectStorage* getStorage() const { return &m_storage; }
+
+    /// Appends object to target object. Targed object reference must be valid.
+    /// Arrays are concatenated.
+    /// \param reference Target object reference
+    /// \param object Object to be appended
+    void appendTo(PDFObjectReference reference, PDFObject object);
+
+    /// Merges object to target object. Targed object reference must be valid.
+    /// Arrays are not concatenated.
+    /// \param reference Target object reference
+    /// \param object Object to be merged
+    void mergeTo(PDFObjectReference reference, PDFObject object);
+
+    /// Sets object by reference
+    /// \param reference Target object reference
+    /// \param object Object to be set
+    void setObject(PDFObjectReference reference, PDFObject object);
+
 /* START GENERATED CODE */
 
     /// Appends a new page after last page.
@@ -823,10 +869,22 @@ public:
     PDFObject createTrailerDictionary(PDFObjectReference catalog);
 
 
+    /// Removes document actions from document catalog.
+    void removeDocumentActions();
+
+
     /// Removes outline tree from document catalog.
     void removeOutline();
 
 
+    /// Removes structure tree from document catalog.
+    void removeStructureTree();
+
+
+    /// Removes threads from document catalog.
+    void removeThreads();
+
+
     /// Sets annotation appearance state.
     /// \param annotation Annotation
     /// \param appearanceState Appearance state
@@ -988,42 +1046,22 @@ public:
     void updateTrailerDictionary(PDFInteger objectCount);
 
 
-    /// Removes threads from document catalog.
+    /// Set optional content properties to catalog.
-    void removeThreads();
+    /// \param ocProperties Reference to catalog optional content properties.
-
+    void setCatalogOptionalContentProperties(PDFObjectReference ocProperties);
-
-    /// Removes document actions from document catalog.
-    void removeDocumentActions();
-
-
-    /// Removes structure tree from document catalog.
-    void removeStructureTree();
 
 
 /* END GENERATED CODE */
 
 private:
-    PDFObjectReference addObject(PDFObject object);
-    void mergeTo(PDFObjectReference reference, PDFObject object);
-    void appendTo(PDFObjectReference reference, PDFObject object);
     QRectF getPopupWindowRect(const QRectF& rectangle) const;
     QString getProducerString() const;
     PDFObjectReference getPageTreeRoot() const;
     PDFInteger getPageTreeRootChildCount() const;
     PDFObjectReference getDocumentInfo() const;
-    PDFObjectReference getCatalogReference() const;
     void updateDocumentInfo(PDFObject info);
     QRectF getPolygonsBoundingRect(const Polygons& Polygons) const;
 
-    /// Copies objects from another storage. Objects have adjusted references to match
-    /// this storage references and objects are added after the last objects of active storage.
-    /// This function can also automatically create references from direct objects passed
-    /// by parameter \p objects, if \p createReferences is set to true.
-    /// \param objects Objects, which we want to copy from another storage
-    /// \param storage Storage, from which we are copying from
-    /// \param createReferences Create references from \p objects
-    std::vector<PDFObject> copyFrom(const std::vector<PDFObject>& objects, const PDFObjectStorage& storage, bool createReferences);
-
     PDFObjectStorage m_storage;
     PDFVersion m_version;
     const PDFFormManager* m_formManager = nullptr;

PdfForQtLib/sources/pdfobject.cpp

@@ -427,6 +427,65 @@ PDFObject PDFObjectManipulator::removeNullObjects(PDFObject object)
     return merge(object, object, RemoveNullObjects);
 }
 
+PDFObject PDFObjectManipulator::removeDuplicitReferencesInArrays(PDFObject object)
+{
+    switch (object.getType())
+    {
+        case PDFObject::Type::Stream:
+        {
+            const PDFStream* stream = object.getStream();
+            PDFDictionary dictionary = *stream->getDictionary();
+
+            for (size_t i = 0, count = dictionary.getCount(); i < count; ++i)
+            {
+                dictionary.setEntry(dictionary.getKey(i), removeDuplicitReferencesInArrays(dictionary.getValue(i)));
+            }
+
+            return PDFObject::createStream(std::make_shared<PDFStream>(qMove(dictionary), QByteArray(*stream->getContent())));
+        }
+
+        case PDFObject::Type::Dictionary:
+        {
+            PDFDictionary dictionary = *object.getDictionary();
+
+            for (size_t i = 0, count = dictionary.getCount(); i < count; ++i)
+            {
+                dictionary.setEntry(dictionary.getKey(i), removeDuplicitReferencesInArrays(dictionary.getValue(i)));
+            }
+
+            return PDFObject::createDictionary(std::make_shared<PDFDictionary>(qMove(dictionary)));
+        }
+
+        case PDFObject::Type::Array:
+        {
+            PDFArray array;
+            std::set<PDFObjectReference> usedReferences;
+
+            for (const PDFObject& object : *object.getArray())
+            {
+                if (object.isReference())
+                {
+                    PDFObjectReference reference = object.getReference();
+                    if (!usedReferences.count(reference))
+                    {
+                        usedReferences.insert(reference);
+                        array.appendItem(PDFObject::createReference(reference));
+                    }
+                }
+                else
+                {
+                    array.appendItem(removeDuplicitReferencesInArrays(object));
+                }
+            }
+
+            return PDFObject::createArray(std::make_shared<PDFArray>(qMove(array)));
+        }
+
+        default:
+            return object;
+    }
+}
+
 QByteArray PDFStringRef::getString() const
 {
     if (inplaceString)

PdfForQtLib/sources/pdfobject.h

@@ -476,7 +476,7 @@ private:
     QByteArray m_content;
 };
 
-class PDFObjectManipulator
+class PDFFORQTLIBSHARED_EXPORT PDFObjectManipulator
 {
 public:
     explicit PDFObjectManipulator() = delete;
@@ -503,6 +503,10 @@ public:
     /// Remove null objects from all dictionaries
     /// \param object Object
     static PDFObject removeNullObjects(PDFObject object);
+
+    /// Remove duplicit references from arrays
+    /// \param object Object
+    static PDFObject removeDuplicitReferencesInArrays(PDFObject object);
 };
 
 }   // namespace pdf

PdfTool/PdfTool.pro

@@ -56,6 +56,7 @@ SOURCES += \
         pdftoolinfostructuretree.cpp \
         pdftoolrender.cpp \
         pdftoolseparate.cpp \
+        pdftoolunite.cpp \
         pdftoolverifysignatures.cpp \
         pdftoolxml.cpp
 
@@ -85,5 +86,6 @@ HEADERS += \
     pdftoolinfostructuretree.h \
     pdftoolrender.h \
     pdftoolseparate.h \
+    pdftoolunite.h \
     pdftoolverifysignatures.h \
     pdftoolxml.h

PdfTool/pdftoolabstractapplication.cpp

@@ -169,6 +169,12 @@ void PDFToolAbstractApplication::initializeCommandLineParser(QCommandLineParser*
         parser->addPositionalArgument("pattern", "Page pattern, must contain '%' character if multiple pages are selected.");
     }
 
+    if (optionFlags.testFlag(Unite))
+    {
+        parser->addPositionalArgument("source", "Documents to be merged into single document.", "file1.pdf [file2.pdf, ...]");
+        parser->addPositionalArgument("target", "Merged document filename.");
+    }
+
     if (optionFlags.testFlag(SignatureVerification))
     {
         parser->addOption(QCommandLineOption("ver-no-user-cert", "Disable user certificate store."));
@@ -809,6 +815,11 @@ PDFToolOptions PDFToolAbstractApplication::getOptions(QCommandLineParser* parser
         options.renderShowPageStatistics = parser->isSet("render-show-page-stat");
     }
 
+    if (optionFlags.testFlag(Unite))
+    {
+        options.uniteFiles = positionalArguments;
+    }
+
     return options;
 }
 

PdfTool/pdftoolabstractapplication.h

@@ -132,6 +132,9 @@ struct PDFToolOptions
     // For option 'Separate'
     QString separatePagePattern;
 
+    // For option 'Unite'
+    QStringList uniteFiles;
+
     /// Returns page range. If page range is invalid, then \p errorMessage is empty.
     /// \param pageCount Page count
     /// \param[out] errorMessage Error message
@@ -160,6 +163,7 @@ public:
     {
         ExitSuccess = EXIT_SUCCESS,
         ExitFailure = EXIT_FAILURE,
+        ErrorUnknown,
         ErrorNoDocumentSpecified,
         ErrorDocumentReading,
         ErrorInvalidArguments,
@@ -198,6 +202,7 @@ public:
         ColorManagementSystem           = 0x00010000,       ///< Color management system settings
         RenderFlags                     = 0x00020000,       ///< Render flags for page image rasterizer
         Separate                        = 0x00040000,       ///< Settings for Separate tool
+        Unite                           = 0x00080000,       ///< Settings for Unite tool
     };
     Q_DECLARE_FLAGS(Options, Option)
 

PdfTool/pdftoolunite.cpp

@@ -0,0 +1,210 @@
+//    Copyright (C) 2020 Jakub Melka
+//
+//    This file is part of PdfForQt.
+//
+//    PdfForQt is free software: you can redistribute it and/or modify
+//    it under the terms of the GNU Lesser General Public License as published by
+//    the Free Software Foundation, either version 3 of the License, or
+//    (at your option) any later version.
+//
+//    PdfForQt is distributed in the hope that it will be useful,
+//    but WITHOUT ANY WARRANTY; without even the implied warranty of
+//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//    GNU Lesser General Public License for more details.
+//
+//    You should have received a copy of the GNU Lesser General Public License
+//    along with PDFForQt.  If not, see <https://www.gnu.org/licenses/>.
+
+#include "pdftoolunite.h"
+#include "pdfdocumentbuilder.h"
+#include "pdfdocumentreader.h"
+#include "pdfoptimizer.h"
+#include "pdfdocumentwriter.h"
+
+namespace pdftool
+{
+
+static PDFToolUnite s_toolUniteApplication;
+
+QString PDFToolUnite::getStandardString(PDFToolAbstractApplication::StandardString standardString) const
+{
+    switch (standardString)
+    {
+        case Command:
+            return "unite";
+
+        case Name:
+            return PDFToolTranslationContext::tr("Merge documents");
+
+        case Description:
+            return PDFToolTranslationContext::tr("Merge multiple documents to a single document.");
+
+        default:
+            Q_ASSERT(false);
+            break;
+    }
+
+    return QString();
+}
+
+int PDFToolUnite::execute(const PDFToolOptions& options)
+{
+    if (options.uniteFiles.size() < 3)
+    {
+        PDFConsole::writeError(PDFToolTranslationContext::tr("At least two documents and target (merged) document must be specified."), options.outputCodec);
+        return ErrorInvalidArguments;
+    }
+
+    QStringList files = options.uniteFiles;
+    QString targetFile = files.back();
+    files.pop_back();
+
+    if (QFileInfo::exists(targetFile))
+    {
+        PDFConsole::writeError(PDFToolTranslationContext::tr("Target file '%1' already exists. Document merging not performed.").arg(targetFile), options.outputCodec);
+        return ErrorFailedWriteToFile;
+    }
+
+    try
+    {
+        pdf::PDFDocumentBuilder documentBuilder;
+        documentBuilder.createDocument();
+
+        pdf::PDFObjectReference ocPropertiesMerged = documentBuilder.addObject(pdf::PDFObject());
+
+        std::vector<pdf::PDFObjectReference> pages;
+        for (const QString& fileName : files)
+        {
+            pdf::PDFDocumentReader reader(nullptr, [](bool* ok) { *ok = false; return QString(); }, options.permissiveReading);
+            pdf::PDFDocument document = reader.readFromFile(fileName);
+            if (reader.getReadingResult() != pdf::PDFDocumentReader::Result::OK)
+            {
+                PDFConsole::writeError(PDFToolTranslationContext::tr("Cannot open document '%1'.").arg(fileName), options.outputCodec);
+                return ErrorDocumentReading;
+            }
+
+            if (!document.getStorage().getSecurityHandler()->isAllowed(pdf::PDFSecurityHandler::Permission::CopyContent))
+            {
+                PDFConsole::writeError(PDFToolTranslationContext::tr("Document doesn't allow to copy content."), options.outputCodec);
+                return ErrorPermissions;
+            }
+
+            pdf::PDFDocumentBuilder temporaryBuilder(&document);
+            temporaryBuilder.flattenPageTree();
+
+            std::vector<pdf::PDFObjectReference> currentPages = temporaryBuilder.getPages();
+            std::vector<pdf::PDFObjectReference> objectsToMerge = currentPages;
+
+            pdf::PDFObjectReference acroFormReference;
+            pdf::PDFObjectReference namesReference;
+            pdf::PDFObjectReference ocPropertiesReference;
+
+            pdf::PDFObject formObject = document.getCatalog()->getFormObject();
+            if (formObject.isReference())
+            {
+                acroFormReference = formObject.getReference();
+            }
+            else
+            {
+                acroFormReference = temporaryBuilder.addObject(formObject);
+            }
+
+            if (const pdf::PDFDictionary* catalogDictionary = temporaryBuilder.getDictionaryFromObject(temporaryBuilder.getObjectByReference(temporaryBuilder.getCatalogReference())))
+            {
+                pdf::PDFObject namesObject = catalogDictionary->get("Names");
+                if (namesObject.isReference())
+                {
+                    namesReference = namesObject.getReference();
+                }
+                else
+                {
+                    namesReference = temporaryBuilder.addObject(namesObject);
+                }
+
+                pdf::PDFObject ocPropertiesObject = catalogDictionary->get("OCProperties");
+                if (ocPropertiesObject.isReference())
+                {
+                    ocPropertiesReference = ocPropertiesObject.getReference();
+                }
+                else
+                {
+                    ocPropertiesReference = temporaryBuilder.addObject(ocPropertiesObject);
+                }
+            }
+
+            if (!namesReference.isValid())
+            {
+                namesReference = temporaryBuilder.addObject(pdf::PDFObject());
+            }
+
+            if (!ocPropertiesReference.isValid())
+            {
+                ocPropertiesReference = temporaryBuilder.addObject(pdf::PDFObject());
+            }
+
+            objectsToMerge.insert(objectsToMerge.end(), { acroFormReference, namesReference, ocPropertiesReference });
+
+            // Now, we are ready to merge objects into targed document builder
+            std::vector<pdf::PDFObjectReference> references = pdf::PDFDocumentBuilder::createReferencesFromObjects(documentBuilder.copyFrom(pdf::PDFDocumentBuilder::createObjectsFromReferences(objectsToMerge), *temporaryBuilder.getStorage(), true));
+
+            ocPropertiesReference = references.back();
+            references.pop_back();
+            namesReference = references.back();
+            references.pop_back();
+            acroFormReference = references.back();
+            references.pop_back();
+
+            documentBuilder.appendTo(ocPropertiesMerged, documentBuilder.getObjectByReference(ocPropertiesReference));
+            pages.insert(pages.end(), references.cbegin(), references.cend());
+        }
+
+        documentBuilder.setPages(pages);
+        if (!documentBuilder.getObjectByReference(ocPropertiesMerged).isNull())
+        {
+            documentBuilder.setCatalogOptionalContentProperties(ocPropertiesMerged);
+        }
+
+        pdf::PDFDocument mergedDocument = documentBuilder.build();
+
+        // Optimize document - remove unused objects and shrink object storage
+        pdf::PDFOptimizer optimizer(pdf::PDFOptimizer::RemoveUnusedObjects | pdf::PDFOptimizer::ShrinkObjectStorage | pdf::PDFOptimizer::DereferenceSimpleObjects | pdf::PDFOptimizer::MergeIdenticalObjects, nullptr);
+        optimizer.setDocument(&mergedDocument);
+        optimizer.optimize();
+        mergedDocument = optimizer.takeOptimizedDocument();
+
+        // We must adjust some objects - they can be merged
+        pdf::PDFDocumentBuilder finalBuilder(&mergedDocument);
+        if (const pdf::PDFDictionary* dictionary = finalBuilder.getDictionaryFromObject(finalBuilder.getObjectByReference(finalBuilder.getCatalogReference())))
+        {
+            pdf::PDFDocumentDataLoaderDecorator loader(finalBuilder.getStorage());
+            pdf::PDFObjectReference ocPropertiesReference = loader.readReferenceFromDictionary(dictionary, "OCProperties");
+            if (ocPropertiesReference.isValid())
+            {
+                finalBuilder.setObject(ocPropertiesReference, pdf::PDFObjectManipulator::removeDuplicitReferencesInArrays(finalBuilder.getObjectByReference(ocPropertiesReference)));
+            }
+        }
+        mergedDocument = finalBuilder.build();
+
+        pdf::PDFDocumentWriter writer(nullptr);
+        pdf::PDFOperationResult result = writer.write(targetFile, &mergedDocument, false);
+        if (!result)
+        {
+            PDFConsole::writeError(result.getErrorMessage(), options.outputCodec);
+            return ErrorFailedWriteToFile;
+        }
+    }
+    catch (pdf::PDFException exception)
+    {
+        PDFConsole::writeError(exception.getMessage(), options.outputCodec);
+        return ErrorUnknown;
+    }
+
+    return ExitSuccess;
+}
+
+PDFToolAbstractApplication::Options PDFToolUnite::getOptionsFlags() const
+{
+    return ConsoleFormat | Unite;
+}
+
+}   // namespace pdftool

PdfTool/pdftoolunite.h

@@ -0,0 +1,36 @@
+//    Copyright (C) 2020 Jakub Melka
+//
+//    This file is part of PdfForQt.
+//
+//    PdfForQt is free software: you can redistribute it and/or modify
+//    it under the terms of the GNU Lesser General Public License as published by
+//    the Free Software Foundation, either version 3 of the License, or
+//    (at your option) any later version.
+//
+//    PdfForQt is distributed in the hope that it will be useful,
+//    but WITHOUT ANY WARRANTY; without even the implied warranty of
+//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//    GNU Lesser General Public License for more details.
+//
+//    You should have received a copy of the GNU Lesser General Public License
+//    along with PDFForQt.  If not, see <https://www.gnu.org/licenses/>.
+
+#ifndef PDFTOOLUNITE_H
+#define PDFTOOLUNITE_H
+
+#include "pdftoolabstractapplication.h"
+
+namespace pdftool
+{
+
+class PDFToolUnite : public PDFToolAbstractApplication
+{
+public:
+    virtual QString getStandardString(StandardString standardString) const override;
+    virtual int execute(const PDFToolOptions& options) override;
+    virtual Options getOptionsFlags() const override;
+};
+
+}   // namespace pdftool
+
+#endif // PDFTOOLUNITE_H

generated_code_definition.xml

@@ -5763,6 +5763,54 @@ return annotationObject;</property>
       <property name="functionDescription">This function is used to create a new trailer dictionary, when blank document is created. Do not call this function manually.</property>
       <property name="returnType">_PDFObject</property>
     </QObject>
+    <QObject class="codegen::GeneratedFunction">
+      <property name="objectName"></property>
+      <property name="items">
+        <QObject class="codegen::GeneratedAction">
+          <property name="objectName"></property>
+          <property name="items">
+            <QObject class="codegen::GeneratedPDFObject">
+              <property name="objectName"></property>
+              <property name="items">
+                <QObject class="codegen::GeneratedPDFObject">
+                  <property name="objectName"></property>
+                  <property name="items"/>
+                  <property name="dictionaryItemName">OpenAction</property>
+                  <property name="objectType">DictionaryItemSimple</property>
+                  <property name="value">PDFObject()</property>
+                </QObject>
+                <QObject class="codegen::GeneratedPDFObject">
+                  <property name="objectName"></property>
+                  <property name="items"/>
+                  <property name="dictionaryItemName">AA</property>
+                  <property name="objectType">DictionaryItemSimple</property>
+                  <property name="value">PDFObject()</property>
+                </QObject>
+              </property>
+              <property name="dictionaryItemName"></property>
+              <property name="objectType">Dictionary</property>
+              <property name="value"></property>
+            </QObject>
+          </property>
+          <property name="actionType">CreateObject</property>
+          <property name="variableName">updatedCatalog</property>
+          <property name="variableType">_PDFObject</property>
+          <property name="code"></property>
+        </QObject>
+        <QObject class="codegen::GeneratedAction">
+          <property name="objectName"></property>
+          <property name="items"/>
+          <property name="actionType">Code</property>
+          <property name="variableName"></property>
+          <property name="variableType">_void</property>
+          <property name="code">mergeTo(getCatalogReference(), updatedCatalog);</property>
+        </QObject>
+      </property>
+      <property name="functionType">Structure</property>
+      <property name="functionName">removeDocumentActions</property>
+      <property name="functionDescription">Removes document actions from document catalog.</property>
+      <property name="returnType">_void</property>
+    </QObject>
     <QObject class="codegen::GeneratedFunction">
       <property name="objectName"></property>
       <property name="items">
@@ -5804,6 +5852,95 @@ return annotationObject;</property>
       <property name="functionDescription">Removes outline tree from document catalog.</property>
       <property name="returnType">_void</property>
     </QObject>
+    <QObject class="codegen::GeneratedFunction">
+      <property name="objectName"></property>
+      <property name="items">
+        <QObject class="codegen::GeneratedAction">
+          <property name="objectName"></property>
+          <property name="items">
+            <QObject class="codegen::GeneratedPDFObject">
+              <property name="objectName"></property>
+              <property name="items">
+                <QObject class="codegen::GeneratedPDFObject">
+                  <property name="objectName"></property>
+                  <property name="items"/>
+                  <property name="dictionaryItemName">StructTreeRoot</property>
+                  <property name="objectType">DictionaryItemSimple</property>
+                  <property name="value">PDFObject()</property>
+                </QObject>
+                <QObject class="codegen::GeneratedPDFObject">
+                  <property name="objectName"></property>
+                  <property name="items"/>
+                  <property name="dictionaryItemName">MarkInfo</property>
+                  <property name="objectType">DictionaryItemSimple</property>
+                  <property name="value">PDFObject()</property>
+                </QObject>
+              </property>
+              <property name="dictionaryItemName"></property>
+              <property name="objectType">Dictionary</property>
+              <property name="value"></property>
+            </QObject>
+          </property>
+          <property name="actionType">CreateObject</property>
+          <property name="variableName">updatedCatalog</property>
+          <property name="variableType">_PDFObject</property>
+          <property name="code"></property>
+        </QObject>
+        <QObject class="codegen::GeneratedAction">
+          <property name="objectName"></property>
+          <property name="items"/>
+          <property name="actionType">Code</property>
+          <property name="variableName"></property>
+          <property name="variableType">_void</property>
+          <property name="code">mergeTo(getCatalogReference(), updatedCatalog);</property>
+        </QObject>
+      </property>
+      <property name="functionType">Structure</property>
+      <property name="functionName">removeStructureTree</property>
+      <property name="functionDescription">Removes structure tree from document catalog.</property>
+      <property name="returnType">_void</property>
+    </QObject>
+    <QObject class="codegen::GeneratedFunction">
+      <property name="objectName"></property>
+      <property name="items">
+        <QObject class="codegen::GeneratedAction">
+          <property name="objectName"></property>
+          <property name="items">
+            <QObject class="codegen::GeneratedPDFObject">
+              <property name="objectName"></property>
+              <property name="items">
+                <QObject class="codegen::GeneratedPDFObject">
+                  <property name="objectName"></property>
+                  <property name="items"/>
+                  <property name="dictionaryItemName">Threads</property>
+                  <property name="objectType">DictionaryItemSimple</property>
+                  <property name="value">PDFObject()</property>
+                </QObject>
+              </property>
+              <property name="dictionaryItemName"></property>
+              <property name="objectType">Dictionary</property>
+              <property name="value"></property>
+            </QObject>
+          </property>
+          <property name="actionType">CreateObject</property>
+          <property name="variableName">updatedCatalog</property>
+          <property name="variableType">_PDFObject</property>
+          <property name="code"></property>
+        </QObject>
+        <QObject class="codegen::GeneratedAction">
+          <property name="objectName"></property>
+          <property name="items"/>
+          <property name="actionType">Code</property>
+          <property name="variableName"></property>
+          <property name="variableType">_void</property>
+          <property name="code">mergeTo(getCatalogReference(), updatedCatalog);</property>
+        </QObject>
+      </property>
+      <property name="functionType">Structure</property>
+      <property name="functionName">removeThreads</property>
+      <property name="functionDescription">Removes threads from document catalog.</property>
+      <property name="returnType">_void</property>
+    </QObject>
     <QObject class="codegen::GeneratedFunction">
       <property name="objectName"></property>
       <property name="items">
@@ -7333,6 +7470,22 @@ updateDocumentInfo(qMove(updatedInfoDictionary));</property>
     <QObject class="codegen::GeneratedFunction">
       <property name="objectName"></property>
       <property name="items">
+        <QObject class="codegen::GeneratedAction">
+          <property name="objectName"></property>
+          <property name="items">
+            <QObject class="codegen::GeneratedParameter">
+              <property name="objectName"></property>
+              <property name="items"/>
+              <property name="parameterName">ocProperties</property>
+              <property name="parameterType">_PDFObjectReference</property>
+              <property name="parameterDescription">Reference to catalog optional content properties.</property>
+            </QObject>
+          </property>
+          <property name="actionType">Parameters</property>
+          <property name="variableName"></property>
+          <property name="variableType">_void</property>
+          <property name="code"></property>
+        </QObject>
         <QObject class="codegen::GeneratedAction">
           <property name="objectName"></property>
           <property name="items">
@@ -7342,9 +7495,9 @@ updateDocumentInfo(qMove(updatedInfoDictionary));</property>
                 <QObject class="codegen::GeneratedPDFObject">
                   <property name="objectName"></property>
                   <property name="items"/>
-                  <property name="dictionaryItemName">Threads</property>
+                  <property name="dictionaryItemName">OCProperties</property>
                   <property name="objectType">DictionaryItemSimple</property>
-                  <property name="value">PDFObject()</property>
+                  <property name="value">ocProperties</property>
                 </QObject>
               </property>
               <property name="dictionaryItemName"></property>
@@ -7367,104 +7520,8 @@ updateDocumentInfo(qMove(updatedInfoDictionary));</property>
         </QObject>
       </property>
       <property name="functionType">Structure</property>
-      <property name="functionName">removeThreads</property>
+      <property name="functionName">setCatalogOptionalContentProperties</property>
-      <property name="functionDescription">Removes threads from document catalog.</property>
+      <property name="functionDescription">Set optional content properties to catalog.</property>
-      <property name="returnType">_void</property>
-    </QObject>
-    <QObject class="codegen::GeneratedFunction">
-      <property name="objectName"></property>
-      <property name="items">
-        <QObject class="codegen::GeneratedAction">
-          <property name="objectName"></property>
-          <property name="items">
-            <QObject class="codegen::GeneratedPDFObject">
-              <property name="objectName"></property>
-              <property name="items">
-                <QObject class="codegen::GeneratedPDFObject">
-                  <property name="objectName"></property>
-                  <property name="items"/>
-                  <property name="dictionaryItemName">OpenAction</property>
-                  <property name="objectType">DictionaryItemSimple</property>
-                  <property name="value">PDFObject()</property>
-                </QObject>
-                <QObject class="codegen::GeneratedPDFObject">
-                  <property name="objectName"></property>
-                  <property name="items"/>
-                  <property name="dictionaryItemName">AA</property>
-                  <property name="objectType">DictionaryItemSimple</property>
-                  <property name="value">PDFObject()</property>
-                </QObject>
-              </property>
-              <property name="dictionaryItemName"></property>
-              <property name="objectType">Dictionary</property>
-              <property name="value"></property>
-            </QObject>
-          </property>
-          <property name="actionType">CreateObject</property>
-          <property name="variableName">updatedCatalog</property>
-          <property name="variableType">_PDFObject</property>
-          <property name="code"></property>
-        </QObject>
-        <QObject class="codegen::GeneratedAction">
-          <property name="objectName"></property>
-          <property name="items"/>
-          <property name="actionType">Code</property>
-          <property name="variableName"></property>
-          <property name="variableType">_void</property>
-          <property name="code">mergeTo(getCatalogReference(), updatedCatalog);</property>
-        </QObject>
-      </property>
-      <property name="functionType">Structure</property>
-      <property name="functionName">removeDocumentActions</property>
-      <property name="functionDescription">Removes document actions from document catalog.</property>
-      <property name="returnType">_void</property>
-    </QObject>
-    <QObject class="codegen::GeneratedFunction">
-      <property name="objectName"></property>
-      <property name="items">
-        <QObject class="codegen::GeneratedAction">
-          <property name="objectName"></property>
-          <property name="items">
-            <QObject class="codegen::GeneratedPDFObject">
-              <property name="objectName"></property>
-              <property name="items">
-                <QObject class="codegen::GeneratedPDFObject">
-                  <property name="objectName"></property>
-                  <property name="items"/>
-                  <property name="dictionaryItemName">StructTreeRoot</property>
-                  <property name="objectType">DictionaryItemSimple</property>
-                  <property name="value">PDFObject()</property>
-                </QObject>
-                <QObject class="codegen::GeneratedPDFObject">
-                  <property name="objectName"></property>
-                  <property name="items"/>
-                  <property name="dictionaryItemName">MarkInfo</property>
-                  <property name="objectType">DictionaryItemSimple</property>
-                  <property name="value">PDFObject()</property>
-                </QObject>
-              </property>
-              <property name="dictionaryItemName"></property>
-              <property name="objectType">Dictionary</property>
-              <property name="value"></property>
-            </QObject>
-          </property>
-          <property name="actionType">CreateObject</property>
-          <property name="variableName">updatedCatalog</property>
-          <property name="variableType">_PDFObject</property>
-          <property name="code"></property>
-        </QObject>
-        <QObject class="codegen::GeneratedAction">
-          <property name="objectName"></property>
-          <property name="items"/>
-          <property name="actionType">Code</property>
-          <property name="variableName"></property>
-          <property name="variableType">_void</property>
-          <property name="code">mergeTo(getCatalogReference(), updatedCatalog);</property>
-        </QObject>
-      </property>
-      <property name="functionType">Structure</property>
-      <property name="functionName">removeStructureTree</property>
-      <property name="functionDescription">Removes structure tree from document catalog.</property>
       <property name="returnType">_void</property>
     </QObject>
   </property>