Handle /Outlines dictionary being a direct object

Even though this case is not valid according to the spec, it has been
seen, and caused an internal error.

ChangeLog

@@ -1,5 +1,11 @@
 2013-06-14  Jay Berkenbilt  <ejb@ql.org>
 
+	* Detect and correct /Outlines dictionary being a direct object
+	when linearizing files.  This is not allowed by the spec but has
+	been seen in the wild.  Prior to this change, such a file would
+	cause an internal error in the linearization code, which assumed
+	/Outlines was indirect.
+
 	* Add /Length key to crypt filter dictionary for encrypted files.
 	This key is optional, but some version of MacOS reportedly fail to
 	open encrypted PDF files without this key.

libqpdf/QPDF_linearization.cc

@@ -958,6 +958,15 @@ QPDF::checkHOutlines(std::list<std::string>& warnings)
 	{
 	    // Check length and offset.  Acrobat gets these wrong.
 	    QPDFObjectHandle outlines = getRoot().getKey("/Outlines");
+            if (! outlines.isIndirect())
+            {
+                // This case is not exercised in test suite since not
+                // permitted by the spec, but if this does occur, the
+                // code below would fail.
+		warnings.push_back(
+		    "/Outlines key of root dictionary is not indirect");
+                return;
+            }
 	    QPDFObjGen og(outlines.getObjGen());
 	    assert(this->xref_table.count(og) > 0);
 	    int offset = getLinearizationOffset(og);

libqpdf/QPDF_optimization.cc

@@ -68,6 +68,20 @@ QPDF::optimize(std::map<int, int> const& object_stream_data,
 	return;
     }
 
+    // The PDF specification indicates that /Outlines is supposed to
+    // be an indirect reference.  Force it to be so if it exists and
+    // is direct.  (This has been seen in the wild.)
+    QPDFObjectHandle root = getRoot();
+    if (root.getKey("/Outlines").isDictionary())
+    {
+        QPDFObjectHandle outlines = root.getKey("/Outlines");
+        if (! outlines.isIndirect())
+        {
+            QTC::TC("qpdf", "QPDF_optimization indirect outlines");
+            root.replaceKey("/Outlines", makeIndirectObject(outlines));
+        }
+    }
+
     // Traverse pages tree pushing all inherited resources down to the
     // page level.  This also initializes this->all_pages.
     pushInheritedAttributesToPage(allow_changes, false);
@@ -97,7 +111,6 @@ QPDF::optimize(std::map<int, int> const& object_stream_data,
 	}
     }
 
-    QPDFObjectHandle root = getRoot();
     keys = root.getKeys();
     for (std::set<std::string>::iterator iter = keys.begin();
 	 iter != keys.end(); ++iter)

qpdf/qpdf.testcov

@@ -263,3 +263,4 @@ QPDFObjectHandle EOF in inline image 0
 QPDFObjectHandle inline image token 0
 QPDF not caching overridden objstm object 0
 QPDFWriter original obj non-zero gen 0
+QPDF_optimization indirect outlines 0

qpdf/qtest/qpdf.test

@@ -1192,6 +1192,7 @@ my @to_linearize =
      'object-stream',		# contains object streams
      'hybrid-xref',	        # contains both xref tables and streams
      'gen1',                    # has objects with generation > 0
+     'direct-outlines',         # /Outlines is a direct object
      @linearized_files,		# we should be able to relinearize
      );