Related: fdo#47644 compound storage backend is poor at knowing stream size

Change-Id: Ie4aa6939f9f37e04fda5425a6e28c5d846a9cb62

sot/inc/sot/stg.hxx

@@ -94,6 +94,7 @@ public:
     virtual sal_Bool    Commit() = 0;
     virtual sal_Bool    Revert() = 0;
     virtual sal_Bool    Equals( const BaseStorageStream& rStream ) const = 0;
+    virtual sal_Size    remainingSize() = 0;
 };
 
 class BaseStorage : public StorageBase
@@ -178,6 +179,7 @@ public:
     virtual sal_Bool    ValidateMode( StreamMode ) const;
     const SvStream* GetSvStream() const;
     virtual sal_Bool    Equals( const BaseStorageStream& rStream ) const;
+    virtual sal_Size    remainingSize();
 };
 
 class UCBStorageStream;
@@ -270,6 +272,7 @@ public:
     virtual sal_Bool                Revert();
     virtual sal_Bool                Validate( sal_Bool=sal_False ) const;
     virtual sal_Bool                ValidateMode( StreamMode ) const;
+    virtual sal_Size                remainingSize();
     const SvStream*             GetSvStream() const;
     virtual sal_Bool                Equals( const BaseStorageStream& rStream ) const;
     sal_Bool                        SetProperty( const String& rName, const ::com::sun::star::uno::Any& rValue );

sot/inc/sot/storage.hxx

@@ -95,6 +95,7 @@ public:
     sal_Bool                GetProperty( const String& rName, ::com::sun::star::uno::Any& rValue );
     ::com::sun::star::uno::Reference< ::com::sun::star::io::XInputStream >
                         GetXInputStream() const;
+    virtual sal_Size remainingSize();
 };
 
 #ifndef SOT_DECL_SOTSTORAGESTREAM_DEFINED

sot/source/sdstor/stg.cxx

@@ -234,6 +234,13 @@ sal_uLong StorageStream::Seek( sal_uLong n )
         return n;
 }
 
+sal_Size StorageStream::remainingSize()
+{
+    if( Validate() )
+        return pEntry->GetSize() - Tell();
+    return 0;
+}
+
 void StorageStream::Flush()
 {
     // Flushing means committing, since streams are never transacted

sot/source/sdstor/storage.cxx

@@ -286,6 +286,13 @@ sal_uInt32 SotStorageStream::GetSize() const
     return nSize;
 }
 
+sal_Size SotStorageStream::remainingSize()
+{
+    if (pOwnStm)
+        return pOwnStm->remainingSize();
+    return SvStream::remainingSize();
+}
+
 /*************************************************************************
 |*    SotStorageStream::CopyTo()
 |*

sot/source/sdstor/ucbstorage.cxx

@@ -1554,6 +1554,11 @@ sal_Bool UCBStorageStream::GetProperty( const String& rName, ::com::sun::star::u
     return sal_False;
 }
 
+sal_Size UCBStorageStream::remainingSize()
+{
+    return pImp->GetSize() - Tell();
+}
+
 UCBStorage::UCBStorage( SvStream& rStrm, sal_Bool bDirect )
 {
     String aURL = GetLinkedFile( rStrm );

tools/inc/tools/stream.hxx

@@ -374,7 +374,7 @@ public:
     sal_Size        SeekRel( sal_sSize nPos );
     sal_Size        Tell() const { return nBufFilePos+nBufActualPos;  }
     //length between current (Tell()) pos and end of stream
-    sal_Size        remainingSize();
+    virtual sal_Size remainingSize();
     void            Flush();
     sal_Bool        IsEof() const { return bIsEof; }
     // next Tell() <= nSize
@@ -789,6 +789,7 @@ public:
     sal_Bool            IsObjectMemoryOwner() { return bOwnsData; }
     void            SetResizeOffset( sal_Size nNewResize ) { nResize = nNewResize; }
     sal_Size            GetResizeOffset() const { return nResize; }
+    virtual sal_Size remainingSize() { return GetSize() - Tell(); }
 };
 
 // --------------------

tools/source/stream/stream.cxx

@@ -1703,9 +1703,9 @@ sal_Size SvStream::Seek( sal_Size nFilePos )
     return nBufFilePos + nBufActualPos;
 }
 
-//probably not as inefficient as it looks seeing as STREAM_SEEK_TO_END in the
-//Seek backends is nomally special cased feel free to make this virtual and add
-//good implementations for SvFileStream etc
+//STREAM_SEEK_TO_END in the some of the Seek backends is special cased to be
+//efficient, in others e.g. SotStorageStream it's really horribly slow, and in
+//those this should be overridden
 sal_Size SvStream::remainingSize()
 {
     sal_Size nCurr = Tell();