pdf: test hybrid mode (PDF attachment) with encryption

This adds a test that checks the attached file is correctly added
to the PDF stream when encryption is enabled.

Also add support for reading of attachments to PDFium wrapper.

The test saves a document as encrypted PDF with hybrid mode enabled,
then opens the document in PDFium and saves the attachment content
to a temporary file, which is opened again and the content checked.

Change-Id: I918f67d269c31fe7826a49473e939d52bac7fe98
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/178629
Reviewed-by: Miklos Vajna <vmiklos@collabora.com>
Tested-by: Jenkins CollaboraOffice <jenkinscollaboraoffice@gmail.com>

1 files changed, 56 insertions, 0 deletions

diff --git a/vcl/source/pdf/PDFiumLibrary.cxx b/vcl/source/pdf/PDFiumLibrary.cxx
index 4ad9af1726d0..d56562f34b74 100644
--- a/vcl/source/pdf/PDFiumLibrary.cxx
+++ b/vcl/source/pdf/PDFiumLibrary.cxx
@@ -20,6 +20,7 @@
 #include <fpdf_save.h>
 #include <fpdf_signature.h>
 #include <fpdf_formfill.h>
+#include <fpdf_attachment.h>
 
 #include <osl/endian.h>
 #include <vcl/bitmap.hxx>
@@ -488,6 +489,23 @@ public:
     FPDF_FORMHANDLE getPointer();
 };
 
+class PDFiumAttachmentImpl final : public PDFiumAttachment
+{
+private:
+    FPDF_ATTACHMENT mpAttachment;
+    PDFiumAttachmentImpl(const PDFiumSignatureImpl&) = delete;
+    PDFiumAttachmentImpl& operator=(const PDFiumSignatureImpl&) = delete;
+
+public:
+    PDFiumAttachmentImpl(FPDF_ATTACHMENT pAttachment)
+        : mpAttachment(pAttachment)
+    {
+    }
+
+    OUString getName() override;
+    bool getFile(std::vector<unsigned char>& rOutBuffer) override;
+};
+
 class PDFiumDocumentImpl : public PDFiumDocument
 {
 private:
@@ -508,11 +526,13 @@ public:
     basegfx::B2DSize getPageSize(int nIndex) override;
     int getPageCount() override;
     int getSignatureCount() override;
+    int getAttachmentCount() override;
     int getFileVersion() override;
     bool saveWithVersion(SvMemoryStream& rStream, int nFileVersion) override;
 
     std::unique_ptr<PDFiumPage> openPage(int nIndex) override;
     std::unique_ptr<PDFiumSignature> getSignature(int nIndex) override;
+    std::unique_ptr<PDFiumAttachment> getAttachment(int nIndex) override;
     std::vector<unsigned int> getTrailerEnds() override;
 };
 
@@ -728,6 +748,29 @@ util::DateTime PDFiumSignatureImpl::getTime()
     return aRet;
 }
 
+OUString PDFiumAttachmentImpl::getName()
+{
+    return getUnicodeString([this](FPDF_WCHAR* buffer, unsigned long length) {
+        return FPDFAttachment_GetName(mpAttachment, buffer, length);
+    });
+}
+
+bool PDFiumAttachmentImpl::getFile(std::vector<unsigned char>& rOutBuffer)
+{
+    rOutBuffer.clear();
+
+    unsigned long nLength{};
+    if (!FPDFAttachment_GetFile(mpAttachment, nullptr, 0, &nLength))
+        return false;
+
+    rOutBuffer.resize(nLength);
+    unsigned long nActualLength{};
+    if (!FPDFAttachment_GetFile(mpAttachment, rOutBuffer.data(), nLength, &nActualLength))
+        return false;
+    rOutBuffer.resize(nActualLength);
+    return true;
+}
+
 PDFiumDocumentImpl::PDFiumDocumentImpl(FPDF_DOCUMENT pPdfDocument)
     : mpPdfDocument(pPdfDocument)
     , m_aFormCallbacks()
@@ -768,6 +811,17 @@ std::unique_ptr<PDFiumSignature> PDFiumDocumentImpl::getSignature(int nIndex)
     return pPDFiumSignature;
 }
 
+std::unique_ptr<PDFiumAttachment> PDFiumDocumentImpl::getAttachment(int nIndex)
+{
+    std::unique_ptr<PDFiumAttachment> pPDFiumAttachment;
+    FPDF_ATTACHMENT pAttachment = FPDFDoc_GetAttachment(mpPdfDocument, nIndex);
+    if (pAttachment)
+    {
+        pPDFiumAttachment = std::make_unique<PDFiumAttachmentImpl>(pAttachment);
+    }
+    return pPDFiumAttachment;
+}
+
 std::vector<unsigned int> PDFiumDocumentImpl::getTrailerEnds()
 {
     int nNumTrailers = FPDF_GetTrailerEnds(mpPdfDocument, nullptr, 0);
@@ -791,6 +845,8 @@ int PDFiumDocumentImpl::getPageCount() { return FPDF_GetPageCount(mpPdfDocument)
 
 int PDFiumDocumentImpl::getSignatureCount() { return FPDF_GetSignatureCount(mpPdfDocument); }
 
+int PDFiumDocumentImpl::getAttachmentCount() { return FPDFDoc_GetAttachmentCount(mpPdfDocument); }
+
 int PDFiumDocumentImpl::getFileVersion()
 {
     int nFileVersion = 0;