Tighten isPageObject (fixes #310)

2 files changed, 14 insertions, 5 deletions

diff --git a/ChangeLog b/ChangeLog
index 5f464987..e62317b8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,14 @@
 2019-04-20  Jay Berkenbilt  <ejb@ql.org>
 
+	* Slightly tighten logic that determines whether an object is a
+	page. The previous logic was sometimes failing to preserve
+	annotations because they were passing the overly loose test for
+	whether something was a page. This fix has a slight risk of
+	causing some extraneous objects to be copied during page splitting
+	and merging for erroneous PDF files whose page objects contain
+	invalid types or are missing the /Type key entirely, both of which
+	would be invalid according to the PDF specification.
+
 	* Revert change that included preservation of outlines (bookmarks)
 	in --split-pages. The way it was implemented caused a very
 	significant performance penalty when splitting pages with
diff --git a/libqpdf/QPDFObjectHandle.cc b/libqpdf/QPDFObjectHandle.cc
index a3a4d61d..f7c78c57 100644
--- a/libqpdf/QPDFObjectHandle.cc
+++ b/libqpdf/QPDFObjectHandle.cc
@@ -2524,14 +2524,14 @@ QPDFObjectHandle::isPageObject()
             return true;
         }
         // Files have been seen in the wild that have /Type (Page)
-        if (type.isString() && (type.getStringValue() == "Page"))
+        else if (type.isString() && (type.getStringValue() == "Page"))
         {
             return true;
         }
-    }
-    if (this->hasKey("/Contents"))
-    {
-        return true;
+        else
+        {
+            return false;
+        }
     }
     return false;
 }