tdf#63130 reduce large memory copies when reading from BinaryDataContainer

rather than writing a bunch more code, extract the common part from
comphelper::SequenceInputStream into a new base class

Change-Id: I0d3561e3ca2e748b904128e3b5955e27196d7170
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/151943
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

2 files changed, 22 insertions, 4 deletions

diff --git a/vcl/source/gdi/vectorgraphicdata.cxx b/vcl/source/gdi/vectorgraphicdata.cxx
index 979fd4f18ad0..7dc51073adeb 100644
--- a/vcl/source/gdi/vectorgraphicdata.cxx
+++ b/vcl/source/gdi/vectorgraphicdata.cxx
@@ -196,8 +196,7 @@ void VectorGraphicData::ensureSequenceAndRange()
     {
         case VectorGraphicDataType::Svg:
         {
-            css::uno::Sequence<sal_Int8> aDataSequence = maDataContainer.getCopyAsByteSequence();
-            const uno::Reference<io::XInputStream> xInputStream(new comphelper::SequenceInputStream(aDataSequence));
+            const uno::Reference<io::XInputStream> xInputStream = maDataContainer.getAsXInputStream();
 
             const uno::Reference< graphic::XSvgParser > xSvgParser = graphic::SvgTools::create(xContext);
 
@@ -211,8 +210,7 @@ void VectorGraphicData::ensureSequenceAndRange()
         {
             const uno::Reference< graphic::XEmfParser > xEmfParser = graphic::EmfTools::create(xContext);
 
-            css::uno::Sequence<sal_Int8> aDataSequence = maDataContainer.getCopyAsByteSequence();
-            const uno::Reference<io::XInputStream> xInputStream(new comphelper::SequenceInputStream(aDataSequence));
+            const uno::Reference<io::XInputStream> xInputStream = maDataContainer.getAsXInputStream();
 
             if (xInputStream.is())
             {
diff --git a/vcl/source/graphic/BinaryDataContainer.cxx b/vcl/source/graphic/BinaryDataContainer.cxx
index f395497f9449..83cacb491ac2 100644
--- a/vcl/source/graphic/BinaryDataContainer.cxx
+++ b/vcl/source/graphic/BinaryDataContainer.cxx
@@ -12,6 +12,7 @@
 #include <o3tl/hash_combine.hxx>
 #include <unotools/tempfile.hxx>
 #include <comphelper/lok.hxx>
+#include <comphelper/seqstream.hxx>
 #include <sal/log.hxx>
 
 struct BinaryDataContainer::Impl
@@ -115,6 +116,19 @@ public:
     {
     }
 };
+
+class ReferencedXInputStream : public comphelper::MemoryInputStream
+{
+    std::shared_ptr<std::vector<sal_uInt8>> mpData;
+
+public:
+    ReferencedXInputStream(const std::shared_ptr<std::vector<sal_uInt8>>& pData)
+        : comphelper::MemoryInputStream(reinterpret_cast<const sal_Int8*>(pData->data()),
+                                        pData->size())
+        , mpData(pData)
+    {
+    }
+};
 }
 
 std::shared_ptr<SvStream> BinaryDataContainer::getAsStream()
@@ -123,6 +137,12 @@ std::shared_ptr<SvStream> BinaryDataContainer::getAsStream()
     return std::make_shared<ReferencedMemoryStream>(mpImpl->mpData);
 }
 
+css::uno::Reference<css::io::XInputStream> BinaryDataContainer::getAsXInputStream()
+{
+    ensureSwappedIn(); // TODO: transfer in streamed chunks
+    return new ReferencedXInputStream(mpImpl->mpData);
+}
+
 std::size_t BinaryDataContainer::writeToStream(SvStream& rStream) const
 {
     ensureSwappedIn(); // TODO: transfer in streamed chunks