sd signature line: teach PDFDocument how to use PDFObjectCopier

This will allow using the object copier in
PDFDocument::WriteAppearanceObject(), so we can include the signature
line pdf export result in a pdf signature of the original pdf.

(cherry picked from commit f9ac4ab61fa2ebcafa8ea8957db01104a927bff2)

Conflicts:
include/vcl/filter/pdfdocument.hxx

Change-Id: Iabc508081c5820f4ca997a2d264de9bdb06f82bd
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/97249
Tested-by: Jenkins CollaboraOffice <jenkinscollaboraoffice@gmail.com>
Reviewed-by: Miklos Vajna <vmiklos@collabora.com>

2 files changed, 47 insertions, 2 deletions

diff --git a/include/vcl/filter/pdfdocument.hxx b/include/vcl/filter/pdfdocument.hxx
index 10ce81afa5be..70e6f79641b8 100644
--- a/include/vcl/filter/pdfdocument.hxx
+++ b/include/vcl/filter/pdfdocument.hxx
@@ -16,9 +16,10 @@
 #include <vector>
 
 #include <tools/stream.hxx>
-
 #include <vcl/dllapi.h>
 
+#include <vcl/filter/pdfobjectcontainer.hxx>
+
 namespace com
 {
 namespace sun
@@ -345,7 +346,7 @@ public:
  * elements remember their source offset / length, and based on that it's
  * possible to modify the input file.
  */
-class VCL_DLLPUBLIC PDFDocument
+class VCL_DLLPUBLIC PDFDocument : public PDFObjectContainer
 {
     /// This vector owns all elements.
     std::vector<std::unique_ptr<PDFElement>> m_aElements;
@@ -392,6 +393,7 @@ class VCL_DLLPUBLIC PDFDocument
 
 public:
     PDFDocument();
+    virtual ~PDFDocument();
     PDFDocument& operator=(const PDFDocument&) = delete;
     PDFDocument(const PDFDocument&) = delete;
     /// @name Low-level functions, to be used by PDFElement subclasses.
@@ -437,6 +439,13 @@ public:
     /// Remove the nth signature from read document in the edit buffer.
     bool RemoveSignature(size_t nPosition);
     //@}
+
+    /// See vcl::PDFObjectContainer::createObject().
+    sal_Int32 createObject() override;
+    /// See vcl::PDFObjectContainer::updateObject().
+    bool updateObject(sal_Int32 n) override;
+    /// See vcl::PDFObjectContainer::writeBuffer().
+    bool writeBuffer(const void* pBuffer, sal_uInt64 nBytes) override;
 };
 
 } // namespace pdfio
diff --git a/include/vcl/filter/pdfobjectcontainer.hxx b/include/vcl/filter/pdfobjectcontainer.hxx
new file mode 100644
index 000000000000..ca4898737e10
--- /dev/null
+++ b/include/vcl/filter/pdfobjectcontainer.hxx
@@ -0,0 +1,36 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#pragma once
+
+#include <sal/types.h>
+
+namespace vcl
+{
+/// Allows creating, updating and writing PDF objects in a container.
+class SAL_NO_VTABLE SAL_DLLPUBLIC_RTTI PDFObjectContainer
+{
+public:
+    /* adds an entry to m_aObjects and returns its index+1,
+     * sets the offset to ~0
+     */
+    virtual sal_Int32 createObject() = 0;
+    /* sets the offset of object n to the current position of output file+1
+     */
+    virtual bool updateObject(sal_Int32 n) = 0;
+
+    // Write pBuffer to the end of the output.
+    virtual bool writeBuffer(const void* pBuffer, sal_uInt64 nBytes) = 0;
+
+protected:
+    ~PDFObjectContainer() noexcept = default;
+};
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */