New features for QPdfWriter

Added new API setDocumentXmpMetadata/documentXmpMetadata and
addFileAttachment

[ChangeLog][QtGui][QPdfWriter] New API to provide external document XMP
metadata and attach files to PDF.

Fixes: QTBUG-78651
Fixes: QTBUG-78764
Change-Id: Ic0b37e8d12899f907001db469080594c14c87655
Reviewed-by: Eirik Aavitsland <eirik.aavitsland@qt.io>

4 files changed, 196 insertions, 33 deletions

diff --git a/src/gui/painting/qpdf.cpp b/src/gui/painting/qpdf.cpp
index 932c3e6f5a..de9fc13331 100644
--- a/src/gui/painting/qpdf.cpp
+++ b/src/gui/painting/qpdf.cpp
@@ -1390,6 +1390,18 @@ void QPdfEngine::setPdfVersion(PdfVersion version)
     d->pdfVersion = version;
 }
 
+void QPdfEngine::setDocumentXmpMetadata(const QByteArray &xmpMetadata)
+{
+    Q_D(QPdfEngine);
+    d->xmpDocumentMetadata = xmpMetadata;
+}
+
+QByteArray QPdfEngine::documentXmpMetadata() const
+{
+    Q_D(const QPdfEngine);
+    return d->xmpDocumentMetadata;
+}
+
 void QPdfEngine::setPageLayout(const QPageLayout &pageLayout)
 {
     Q_D(QPdfEngine);
@@ -1520,6 +1532,8 @@ bool QPdfEngine::begin(QPaintDevice *pdev)
 
     d->xrefPositions.clear();
     d->pageRoot = 0;
+    d->embeddedfilesRoot = 0;
+    d->namesRoot = 0;
     d->catalog = 0;
     d->info = 0;
     d->graphicsState = 0;
@@ -1555,10 +1569,18 @@ bool QPdfEngine::end()
         d->outDevice = nullptr;
     }
 
+    d->fileCache.clear();
+
     setActive(false);
     return true;
 }
 
+void QPdfEngine::addFileAttachment(const QString &fileName, const QByteArray &data, const QString &mimeType)
+{
+    Q_D(QPdfEngine);
+    d->fileCache.push_back({fileName, data, mimeType});
+}
+
 QPdfEnginePrivate::~QPdfEnginePrivate()
 {
     qDeleteAll(fonts);
@@ -1586,13 +1608,19 @@ void QPdfEnginePrivate::writeHeader()
 
     int metaDataObj = -1;
     int outputIntentObj = -1;
+    if (pdfVersion == QPdfEngine::Version_A1b || !xmpDocumentMetadata.isEmpty()) {
+        metaDataObj = writeXmpDcumentMetaData();
+    }
     if (pdfVersion == QPdfEngine::Version_A1b) {
-        metaDataObj = writeXmpMetaData();
         outputIntentObj = writeOutputIntent();
     }
 
     catalog = addXrefEntry(-1);
     pageRoot = requestObject();
+    if (!fileCache.isEmpty()) {
+        namesRoot = requestObject();
+        embeddedfilesRoot = requestObject();
+    }
 
     // catalog
     {
@@ -1602,10 +1630,15 @@ void QPdfEnginePrivate::writeHeader()
           << "/Type /Catalog\n"
           << "/Pages " << pageRoot << "0 R\n";
 
-        if (pdfVersion == QPdfEngine::Version_A1b) {
-            s << "/OutputIntents [" << outputIntentObj << "0 R]\n";
+        // Embedded files, if any
+        if (!fileCache.isEmpty())
+            s << "/Names " << embeddedfilesRoot << "0 R\n";
+
+        if (pdfVersion == QPdfEngine::Version_A1b || !xmpDocumentMetadata.isEmpty())
             s << "/Metadata " << metaDataObj << "0 R\n";
-        }
+
+        if (pdfVersion == QPdfEngine::Version_A1b)
+            s << "/OutputIntents [" << outputIntentObj << "0 R]\n";
 
         s << ">>\n"
           << "endobj\n";
@@ -1613,6 +1646,12 @@ void QPdfEnginePrivate::writeHeader()
         write(catalog);
     }
 
+    if (!fileCache.isEmpty()) {
+        addXrefEntry(embeddedfilesRoot);
+        xprintf("<</EmbeddedFiles %d 0 R>>\n"
+                "endobj\n", namesRoot);
+    }
+
     // graphics state
     graphicsState = addXrefEntry(-1);
     xprintf("<<\n"
@@ -1664,39 +1703,45 @@ void QPdfEnginePrivate::writeInfo()
             "endobj\n");
 }
 
-int QPdfEnginePrivate::writeXmpMetaData()
+int QPdfEnginePrivate::writeXmpDcumentMetaData()
 {
     const int metaDataObj = addXrefEntry(-1);
+    QByteArray metaDataContent;
+
+    if (xmpDocumentMetadata.isEmpty()) {
+        const QString producer(QString::fromLatin1("Qt " QT_VERSION_STR));
+
+        const QDateTime now = QDateTime::currentDateTime();
+        const QDate date = now.date();
+        const QTime time = now.time();
+        const QString timeStr =
+                QString::asprintf("%d-%02d-%02dT%02d:%02d:%02d",
+                                  date.year(), date.month(), date.day(),
+                                  time.hour(), time.minute(), time.second());
+
+        const int offset = now.offsetFromUtc();
+        const int hours  = (offset / 60) / 60;
+        const int mins   = (offset / 60) % 60;
+        QString tzStr;
+        if (offset < 0)
+            tzStr = QString::asprintf("-%02d:%02d", -hours, -mins);
+        else if (offset > 0)
+            tzStr = QString::asprintf("+%02d:%02d", hours , mins);
+        else
+            tzStr = QLatin1String("Z");
 
-    const QString producer(QString::fromLatin1("Qt " QT_VERSION_STR));
-
-    const QDateTime now = QDateTime::currentDateTime();
-    const QDate date = now.date();
-    const QTime time = now.time();
-    const QString timeStr =
-            QString::asprintf("%d-%02d-%02dT%02d:%02d:%02d",
-                              date.year(), date.month(), date.day(),
-                              time.hour(), time.minute(), time.second());
+        const QString metaDataDate = timeStr + tzStr;
 
-    const int offset = now.offsetFromUtc();
-    const int hours  = (offset / 60) / 60;
-    const int mins   = (offset / 60) % 60;
-    QString tzStr;
-    if (offset < 0)
-        tzStr = QString::asprintf("-%02d:%02d", -hours, -mins);
-    else if (offset > 0)
-        tzStr = QString::asprintf("+%02d:%02d", hours , mins);
+        QFile metaDataFile(QLatin1String(":/qpdf/qpdfa_metadata.xml"));
+        metaDataFile.open(QIODevice::ReadOnly);
+        metaDataContent = QString::fromUtf8(metaDataFile.readAll()).arg(producer.toHtmlEscaped(),
+                                                                        title.toHtmlEscaped(),
+                                                                        creator.toHtmlEscaped(),
+                                                                        metaDataDate).toUtf8();
+    }
     else
-        tzStr = QLatin1String("Z");
+        metaDataContent = xmpDocumentMetadata;
 
-    const QString metaDataDate = timeStr + tzStr;
-
-    QFile metaDataFile(QLatin1String(":/qpdf/qpdfa_metadata.xml"));
-    metaDataFile.open(QIODevice::ReadOnly);
-    const QByteArray metaDataContent = QString::fromUtf8(metaDataFile.readAll()).arg(producer.toHtmlEscaped(),
-                                                                                     title.toHtmlEscaped(),
-                                                                                     creator.toHtmlEscaped(),
-                                                                                     metaDataDate).toUtf8();
     xprintf("<<\n"
             "/Type /Metadata /Subtype /XML\n"
             "/Length %d\n"
@@ -1774,6 +1819,56 @@ void QPdfEnginePrivate::writePageRoot()
             "endobj\n");
 }
 
+void QPdfEnginePrivate::writeAttachmentRoot()
+{
+    if (fileCache.isEmpty())
+        return;
+
+    QVector<int> attachments;
+    const int size = fileCache.size();
+    for (int i = 0; i < size; ++i) {
+        auto attachment = fileCache.at(i);
+        const int attachmentID = addXrefEntry(-1);
+        xprintf("<<\n");
+        if (do_compress)
+            xprintf("/Filter /FlateDecode\n");
+
+        const int lenobj = requestObject();
+        xprintf("/Length %d 0 R\n", lenobj);
+        int len = 0;
+        xprintf(">>\nstream\n");
+        len = writeCompressed(attachment.data);
+        xprintf("\nendstream\n"
+                "endobj\n");
+        addXrefEntry(lenobj);
+        xprintf("%d\n"
+                "endobj\n", len);
+
+        attachments.push_back(addXrefEntry(-1));
+        xprintf("<<\n"
+                "/F (%s)", attachment.fileName.toLatin1().constData());
+
+        xprintf("\n/EF <</F %d 0 R>>\n"
+                "/Type/Filespec\n"
+                 , attachmentID);
+        if (!attachment.mimeType.isEmpty())
+            xprintf("/Subtype/%s\n",
+                    attachment.mimeType.replace(QLatin1String("/"),
+                                                QLatin1String("#2F")).toLatin1().constData());
+        xprintf(">>\nendobj\n");
+    }
+
+    // names
+    addXrefEntry(namesRoot);
+    xprintf("<</Names[");
+    for (int i = 0; i < size; ++i) {
+        auto attachment = fileCache.at(i);
+        printString(attachment.fileName);
+        xprintf("%d 0 R\n", attachments.at(i));
+    }
+    xprintf("]>>\n"
+            "endobj\n");
+}
 
 void QPdfEnginePrivate::embedFont(QFontSubset *font)
 {
@@ -2031,6 +2126,8 @@ void QPdfEnginePrivate::writeTail()
     writePage();
     writeFonts();
     writePageRoot();
+    writeAttachmentRoot();
+
     addXrefEntry(xrefPositions.size(),false);
     xprintf("xref\n"
             "0 %d\n"
diff --git a/src/gui/painting/qpdf_p.h b/src/gui/painting/qpdf_p.h
index 89e549614a..57d70db442 100644
--- a/src/gui/painting/qpdf_p.h
+++ b/src/gui/painting/qpdf_p.h
@@ -187,6 +187,11 @@ public:
 
     void setPdfVersion(PdfVersion version);
 
+    void setDocumentXmpMetadata(const QByteArray &xmpMetadata);
+    QByteArray documentXmpMetadata() const;
+
+    void addFileAttachment(const QString &fileName, const QByteArray &data, const QString &mimeType);
+
     // reimplementations QPaintEngine
     bool begin(QPaintDevice *pdev) override;
     bool end() override;
@@ -297,9 +302,10 @@ private:
     int createShadingFunction(const QGradient *gradient, int from, int to, bool reflect, bool alpha);
 
     void writeInfo();
-    int writeXmpMetaData();
+    int writeXmpDcumentMetaData();
     int writeOutputIntent();
     void writePageRoot();
+    void writeAttachmentRoot();
     void writeFonts();
     void embedFont(QFontSubset *font);
     qreal calcUserUnit() const;
@@ -324,11 +330,22 @@ private:
     inline int writeCompressed(const QByteArray &data) { return writeCompressed(data.constData(), data.length()); }
     int writeCompressed(QIODevice *dev);
 
+    struct AttachmentInfo
+    {
+        AttachmentInfo (const QString &fileName, const QByteArray &data, const QString &mimeType)
+            : fileName(fileName), data(data), mimeType(mimeType) {}
+        QString fileName;
+        QByteArray data;
+        QString mimeType;
+    };
+
     // various PDF objects
-    int pageRoot, catalog, info, graphicsState, patternColorSpace;
+    int pageRoot, embeddedfilesRoot, namesRoot, catalog, info, graphicsState, patternColorSpace;
     QVector<uint> pages;
     QHash<qint64, uint> imageCache;
     QHash<QPair<uint, uint>, uint > alphaCache;
+    QVector<AttachmentInfo> fileCache;
+    QByteArray xmpDocumentMetadata;
 };
 
 QT_END_NAMESPACE
diff --git a/src/gui/painting/qpdfwriter.cpp b/src/gui/painting/qpdfwriter.cpp
index 35814d146c..4f70fe6ad2 100644
--- a/src/gui/painting/qpdfwriter.cpp
+++ b/src/gui/painting/qpdfwriter.cpp
@@ -266,6 +266,50 @@ int QPdfWriter::resolution() const
     return d->engine->resolution();
 }
 
+/*!
+    \since 5.15
+
+    Sets the document metadata. This metadata is not influenced by the setTitle / setCreator methods,
+    so is up to the user to keep it consistent.
+    \a xmpMetadata contains XML formatted metadata to embed into the PDF file.
+
+    \sa documentXmpMetadata()
+*/
+
+void QPdfWriter::setDocumentXmpMetadata(const QByteArray &xmpMetadata)
+{
+    Q_D(const QPdfWriter);
+    d->engine->setDocumentXmpMetadata(xmpMetadata);
+}
+
+/*!
+    \since 5.15
+
+    Gets the document metadata, as it was provided with a call to setDocumentXmpMetadata. It will not
+    return the default metadata.
+
+    \sa setDocumentXmpMetadata()
+*/
+
+QByteArray QPdfWriter::documentXmpMetadata() const
+{
+    Q_D(const QPdfWriter);
+    return d->engine->documentXmpMetadata();
+}
+
+/*!
+    \since 5.15
+
+    Adds \a fileName attachment to the PDF with (optional) \a mimeType
+    \a data contains the raw file data to embed into the PDF file.
+*/
+
+void QPdfWriter::addFileAttachment(const QString &fileName, const QByteArray &data, const QString &mimeType)
+{
+    Q_D(QPdfWriter);
+    d->engine->addFileAttachment(fileName, data, mimeType);
+}
+
 // Defined in QPagedPaintDevice but non-virtual, add QPdfWriter specific doc here
 #ifdef Q_QDOC
 /*!
diff --git a/src/gui/painting/qpdfwriter.h b/src/gui/painting/qpdfwriter.h
index 668081e008..04039a0104 100644
--- a/src/gui/painting/qpdfwriter.h
+++ b/src/gui/painting/qpdfwriter.h
@@ -75,6 +75,11 @@ public:
     void setResolution(int resolution);
     int resolution() const;
 
+    void setDocumentXmpMetadata(const QByteArray &xmpMetadata);
+    QByteArray documentXmpMetadata() const;
+
+    void addFileAttachment(const QString &fileName, const QByteArray &data, const QString &mimeType = QString());
+
 #ifdef Q_QDOC
     bool setPageLayout(const QPageLayout &pageLayout);
     bool setPageSize(const QPageSize &pageSize);