Ensure pdfi stream lives long enough (use stable_memory)

To avoid problems with objects moving in gc memory, we "clone" the PS file
object in order to pass it into pdfi (it also avoids problems with the PS
code moving the file position under pdfi's feet).

In the event of an error from pdfi provoking a Postscript error, we can end up
with the underlying file object being closed by a PS restore, while the PDF
stream still exists. If that then gets restored away, or gc'ed before the
pdfctx_t, it will also try to close the underlying file object, causing
problems.

Moving the PDF stream to stable memory ensuring it won't get restored away,
and won't get gc'ed until after the pdfctx_t is freed (by whatever means).

That, in turn, means that the pdfctx_t finalize method can take its special
action with the cloned stream, specifically intended to avoid exactly this
kind of issue.

1 files changed, 2 insertions, 2 deletions

diff --git a/psi/zpdfops.c b/psi/zpdfops.c
index 11dccca99..7023592b0 100644
--- a/psi/zpdfops.c
+++ b/psi/zpdfops.c
@@ -518,8 +518,8 @@ static int zPDFstream(i_ctx_t *i_ctx_p)
 
     s->close_at_eod = false;
     pdfctx->ps_stream = s;
-    pdfctx->pdf_stream = s_alloc_immovable(imemory, "PDFstream copy of PS stream");
-    pdfctx->pdf_stream_memory = imemory;
+    pdfctx->pdf_stream = s_alloc_immovable(imemory->stable_memory, "PDFstream copy of PS stream");
+    pdfctx->pdf_stream_memory = imemory->stable_memory;
     if (pdfctx->pdf_stream == NULL)
         return_error(gs_error_VMerror);