Don't unlock a lock we don't own.

While debugging Bug 692943, I spotted a case where we can attempt to
unlock the file while we don't hold the file lock due to an error
being thrown while we momentarily drop that lock. Simple solution
is to add a new fz_try()/fz_catch() to retake the lock in such
an error circumstance.

1 files changed, 12 insertions, 2 deletions

diff --git a/pdf/pdf_repair.c b/pdf/pdf_repair.c
index fda1e6b5..a51b9631 100644
--- a/pdf/pdf_repair.c
+++ b/pdf/pdf_repair.c
@@ -390,8 +390,18 @@ pdf_repair_xref(pdf_document *xref, pdf_lexbuf *buf)
 			if (list[i].stm_len >= 0)
 			{
 				fz_unlock(ctx, FZ_LOCK_FILE);
-				dict = pdf_load_object(xref, list[i].num, list[i].gen);
-				fz_lock(ctx, FZ_LOCK_FILE);
+				fz_try(ctx)
+				{
+					dict = pdf_load_object(xref, list[i].num, list[i].gen);
+				}
+				fz_always(ctx)
+				{
+					fz_lock(ctx, FZ_LOCK_FILE);
+				}
+				fz_catch(ctx)
+				{
+					fz_rethrow(ctx);
+				}
 				/* RJW: "cannot load stream object (%d %d R)", list[i].num, list[i].gen */
 
 				length = pdf_new_int(ctx, list[i].stm_len);