PDF: Add a "Using Poppler $VERSION" string

It is sometimes useful to know which version of the poppler you're using
and to which you where built

Needs feature introduced in poppler just now

generators/poppler/CMakeLists.txt

@@ -107,6 +107,15 @@ int main()
 }
 " HAVE_POPPLER_0_69)
 
+check_cxx_source_compiles("
+#include <poppler-version.h>
+int main()
+{
+    QString s = Poppler::Version::string();
+    return 0;
+}
+" HAVE_POPPLER_0_73)
+
 configure_file(
    ${CMAKE_CURRENT_SOURCE_DIR}/config-okular-poppler.h.cmake
    ${CMAKE_CURRENT_BINARY_DIR}/config-okular-poppler.h

generators/poppler/config-okular-poppler.h.cmake

@@ -33,3 +33,6 @@
 
 /* Defined if we have the 0.69 version of the Poppler library */
 #cmakedefine HAVE_POPPLER_0_69 1
+
+/* Defined if we have the 0.73 version of the Poppler library */
+#cmakedefine HAVE_POPPLER_0_73 1

generators/poppler/generator_pdf.cpp

@@ -53,6 +53,7 @@
 #include <config-okular-poppler.h>
 
 #include <poppler-media.h>
+#include <poppler-version.h>
 
 #include "debug_pdf.h"
 #include "annots.h"
@@ -1490,6 +1491,16 @@ QVariant PDFGenerator::metaData( const QString & key, const QVariant & option )
 #ifdef HAVE_POPPLER_0_53
         QMutexLocker ml(userMutex());
         return QVariant::fromValue<QVector<int>>(pdfdoc->formCalculateOrder());
+#endif
+    }
+    else if ( key == QLatin1String("GeneratorExtraDescription") )
+    {
+#ifdef HAVE_POPPLER_0_73
+        if (Poppler::Version::string() == POPPLER_VERSION) {
+            return i18n("Using Poppler %1", Poppler::Version::string());
+        } else {
+            return i18n("Using Poppler %1\n\nBuilt against Poppler %2", Poppler::Version::string(), POPPLER_VERSION);
+        }
 #endif
     }
     return QVariant();

part.cpp

@@ -3166,6 +3166,11 @@ void Part::slotAboutBackend()
         }
     }
 
+    const QString extraDescription = m_document->metaData( QStringLiteral("GeneratorExtraDescription") ).toString();
+    if (!extraDescription.isEmpty()) {
+        aboutData.setShortDescription(aboutData.shortDescription() + QStringLiteral("\n\n") + extraDescription);
+    }
+
     if (!icon.isNull()) {
         // 48x48 is what KAboutApplicationDialog wants, which doesn't match any default so we hardcode it
         aboutData.setProgramLogo(icon.pixmap(48, 48));