throw exception in SvStream when reading past end of file

to avoid chasing weird problems where we read past the end
of file, which leads to random data in the variable we read into.

I expect a couple of possible regressions from this change

(1) memory leaks caused by non-exception-safe memory handling.
Of which there should not be much because we're pretty good
about using smart pointer classes these days.

(2) Broken files which used to load, will no longer do so.
These will have to be debugged by putting a breakpoint
on the SvStreamEOFException constructor, and examining
the backtrace to see where we should be catching and ignoring
the exception to make the code continue to handle such broken
files.

Change-Id: I351be031bb083a3484a9a1b650a58892700e6fb7
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/105936
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

1 files changed, 7 insertions, 3 deletions

diff --git a/include/tools/stream.hxx b/include/tools/stream.hxx
index 7e79516d8407..2032b30f1d74 100644
--- a/include/tools/stream.hxx
+++ b/include/tools/stream.hxx
@@ -16,8 +16,7 @@
  *   except in compliance with the License. You may obtain a copy of
  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  */
-#ifndef INCLUDED_TOOLS_STREAM_HXX
-#define INCLUDED_TOOLS_STREAM_HXX
+#pragma once
 
 #include <tools/toolsdllapi.h>
 #include <tools/lineend.hxx>
@@ -673,6 +672,11 @@ public:
     virtual sal_uInt64 TellEnd() override { FlushBuffer(); return nEndOfData; }
 };
 
-#endif
+/** thrown when reading past the end of file */
+class TOOLS_DLLPUBLIC SvStreamEOFException : public std::exception
+{
+public:
+    virtual const char * what() const throw() override;
+};
 
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