Related rhbz#1259746: Buffer file content read from GIO UCP

...for one, this avoids sending seek requests down the GIO/GVFS stack, which can
silently fail with corrupt data read from certain broken servers for current
versions of the GIO/GVFS stack; for another, it should considerably speed up
loading documents via the GIO UCP, as LO's document type detection is notorious
for issuing lots of seek and (small-chunk and/or re-) read operations on a file.

(This issue has become more relevant after
51e0d789 "rhbz#1134285: Access dav, davs URLs
via GVFS," where the old route via the WebDAV UCP was apparently not affected by
those broken servers, so happened to start affecting opening certain remote
files in LO via Nautilus.)

Change-Id: I91f91128b2d1a16f976eafeacf216a91747f4df1
(cherry picked from commit 93a0696e)
Reviewed-on: https://gerrit.libreoffice.org/18612Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

ucb/source/ucp/gio/gio_content.cxx

@@ -59,6 +59,7 @@
 #include <com/sun/star/ucb/XContentCreator.hpp>
 
 #include <comphelper/processfactory.hxx>
+#include <comphelper/seekableinput.hxx>
 #include <cppuhelper/exc_hlp.hxx>
 #include <ucbhelper/contentidentifier.hxx>
 #include <ucbhelper/propertyvalueset.hxx>
@@ -846,9 +847,9 @@ bool Content::feedSink( uno::Reference< uno::XInterface > xSink,
     if (!pStream)
        convertToException(pError, static_cast< cppu::OWeakObject * >(this));
 
-    uno::Reference< io::XInputStream > xIn = new ::gio::InputStream(pStream);
-    if ( !xIn.is() )
-        return false;
+    uno::Reference< io::XInputStream > xIn(
+        new comphelper::OSeekableInputWrapper(
+            new ::gio::InputStream(pStream), m_xContext));
 
     if ( xOut.is() )
         copyData( xIn, xOut );

ucb/source/ucp/gio/gio_inputstream.cxx

@@ -29,7 +29,7 @@ using namespace com::sun::star;
 namespace gio
 {
 
-InputStream::InputStream(GFileInputStream *pStream) : Seekable(G_SEEKABLE(pStream)), mpStream(pStream)
+InputStream::InputStream(GFileInputStream *pStream): mpStream(pStream)
 {
     if (!mpStream)
         throw io::NotConnectedException();
@@ -57,16 +57,11 @@ void SAL_CALL InputStream::skipBytes( sal_Int32 nBytesToSkip )
     throw( io::NotConnectedException, io::BufferSizeExceededException,
       io::IOException, uno::RuntimeException, std::exception )
 {
-    if (!mpStream)
-        throw io::NotConnectedException();
-
-    if (!g_seekable_can_seek(G_SEEKABLE(mpStream)))
-        throw io::IOException("Seek unsupported",
-            static_cast< cppu::OWeakObject * >(this));
-
-    GError *pError=NULL;
-    if (!g_seekable_seek(G_SEEKABLE(mpStream), nBytesToSkip, G_SEEK_CUR, NULL, &pError))
-        convertToIOException(pError, static_cast< cppu::OWeakObject * >(this));
+    // Conservatively call readBytes and discard the read data, but given this
+    // InputStream will always be wrapped in comphelper::OSeekableInputWrapper,
+    // this function will never be called anyway:
+    css::uno::Sequence<sal_Int8> data;
+    readBytes(data, nBytesToSkip);
 }
 
 sal_Int32 SAL_CALL InputStream::readBytes( uno::Sequence< sal_Int8 >& aData, sal_Int32 nBytesToRead )
@@ -100,14 +95,6 @@ sal_Int32 SAL_CALL InputStream::readSomeBytes( uno::Sequence< sal_Int8 >& aData,
     return readBytes(aData, nMaxBytesToRead);
 }
 
-uno::Any InputStream::queryInterface( const uno::Type &type ) throw( uno::RuntimeException, std::exception )
-{
-    uno::Any aRet = ::cppu::queryInterface ( type,
-        static_cast< XInputStream * >( this ) );
-
-    return aRet.hasValue() ? aRet : Seekable::queryInterface( type );
-}
-
 }
 
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */

ucb/source/ucp/gio/gio_inputstream.hxx

@@ -22,20 +22,16 @@
 
 #include <sal/types.h>
 #include <rtl/ustring.hxx>
-#include <cppuhelper/weak.hxx>
+#include <cppuhelper/implbase.hxx>
 
 #include <com/sun/star/io/XInputStream.hpp>
-#include <com/sun/star/io/XTruncate.hpp>
-#include <com/sun/star/io/XSeekable.hpp>
 
-#include "gio_seekable.hxx"
+#include <gio/gio.h>
 
 namespace gio
 {
 
-class InputStream :
-    public ::com::sun::star::io::XInputStream,
-    public Seekable
+class InputStream: public cppu::WeakImplHelper<css::io::XInputStream>
 {
 private:
     GFileInputStream *mpStream;
@@ -44,12 +40,6 @@ public:
     InputStream ( GFileInputStream *pStream );
     virtual ~InputStream();
 
-    // XInterface
-    virtual com::sun::star::uno::Any SAL_CALL queryInterface(const ::com::sun::star::uno::Type & type )
-            throw( ::com::sun::star::uno::RuntimeException, std::exception ) SAL_OVERRIDE;
-    virtual void SAL_CALL acquire() throw () SAL_OVERRIDE { OWeakObject::acquire(); }
-    virtual void SAL_CALL release() throw() SAL_OVERRIDE { OWeakObject::release(); }
-
     // XInputStream
     virtual sal_Int32 SAL_CALL readBytes( ::com::sun::star::uno::Sequence< sal_Int8 > & aData,
         sal_Int32 nBytesToRead )