Handle indirect stream filter/decode parameters

QPDFWriter was trying to make /Filter and /DecodeParms direct in all
cases, but there are some cases where /DecodeParms may refer to a
stream, which can't be direct. QPDFWriter doesn't actually need
/DecodeParms to be direct in that case because it won't be able to
filter the stream. Until we can handle this type of stream, just don't
make /Filter and /DecodeParms direct if we can't filter the stream
anyway.

Fixes #34

5 files changed, 150 insertions, 3 deletions

diff --git a/ChangeLog b/ChangeLog
index d722e3c0..a83108cb 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2014-06-07  Jay Berkenbilt  <ejb@ql.org>
+
+	* Bug fix: don't fail on files that contain streams where /Filter
+	or /DecodeParms references a stream. Before, qpdf would try to
+	convert these to direct objects, which would fail because of the
+	stream.
+
 2014-02-22  Jay Berkenbilt  <ejb@ql.org>
 
 	* Bug fix: if the last object in the first part of a linearized
diff --git a/libqpdf/QPDFWriter.cc b/libqpdf/QPDFWriter.cc
index 0f299a45..08647e37 100644
--- a/libqpdf/QPDFWriter.cc
+++ b/libqpdf/QPDFWriter.cc
@@ -2051,11 +2051,14 @@ QPDFWriter::prepareFileForWrite()
 	{
             bool is_stream = false;
             bool is_root = false;
+            bool filterable = false;
 	    QPDFObjectHandle dict = node;
 	    if (node.isStream())
 	    {
                 is_stream = true;
 		dict = node.getDict();
+                // See whether we are able to filter this stream.
+                filterable = node.pipeStreamData(0, true, false, false);
 	    }
             else if (pdf.getRoot().getObjectID() == node.getObjectID())
             {
@@ -2073,8 +2076,9 @@ QPDFWriter::prepareFileForWrite()
                 {
                     if (oh.isIndirect() &&
                         ((key == "/Length") ||
-                         (key == "/Filter") ||
-                         (key == "/DecodeParms")))
+                         (filterable &&
+                          ((key == "/Filter") ||
+                           (key == "/DecodeParms")))))
                     {
                         QTC::TC("qpdf", "QPDFWriter make stream key direct");
                         add_to_queue = false;
diff --git a/qpdf/qtest/qpdf.test b/qpdf/qtest/qpdf.test
index d54adc7e..8e697844 100644
--- a/qpdf/qtest/qpdf.test
+++ b/qpdf/qtest/qpdf.test
@@ -199,7 +199,7 @@ $td->runtest("remove page we don't have",
 show_ntests();
 # ----------
 $td->notify("--- Miscellaneous Tests ---");
-$n_tests += 70;
+$n_tests += 72;
 
 $td->runtest("qpdf version",
 	     {$td->COMMAND => "qpdf --version"},
@@ -546,6 +546,14 @@ $td->runtest("sanity check array size",
               $td->EXIT_STATUS => 2},
              $td->NORMALIZE_NEWLINES);
 
+$td->runtest("stream with indirect decode parms",
+             {$td->COMMAND =>
+                  "qpdf --static-id indirect-decode-parms.pdf a.pdf"},
+             {$td->STRING => "", $td->EXIT_STATUS => 0});
+$td->runtest("check file",
+             {$td->FILE => "a.pdf"},
+             {$td->FILE => "indirect-decode-parms-out.pdf"});
+
 show_ntests();
 # ----------
 $td->notify("--- Numeric range parsing tests ---");
diff --git a/qpdf/qtest/qpdf/indirect-decode-parms-out.pdf b/qpdf/qtest/qpdf/indirect-decode-parms-out.pdf
new file mode 100644
index 00000000..4f6bd357
--- /dev/null
+++ b/qpdf/qtest/qpdf/indirect-decode-parms-out.pdf
diff --git a/qpdf/qtest/qpdf/indirect-decode-parms.pdf b/qpdf/qtest/qpdf/indirect-decode-parms.pdf
new file mode 100644
index 00000000..25f4f01d
--- /dev/null
+++ b/qpdf/qtest/qpdf/indirect-decode-parms.pdf
@@ -0,0 +1,128 @@
+%PDF-1.3
+%¿÷¢þ
+%QDF-1.0
+
+1 0 obj
+<<
+  /Pages 2 0 R
+  /Type /Catalog
+>>
+endobj
+
+2 0 obj
+<<
+  /Count 1
+  /Kids [
+    3 0 R
+  ]
+  /Type /Pages
+>>
+endobj
+
+%% Page 1
+3 0 obj
+<<
+  /Contents 4 0 R
+  /MediaBox [
+    0
+    0
+    612
+    792
+  ]
+  /Parent 2 0 R
+  /Resources <<
+    /Font <<
+      /F1 6 0 R
+    >>
+    /ProcSet 7 0 R
+  >>
+  /Type /Page
+>>
+endobj
+
+%% Contents for page 1
+4 0 obj
+<<
+  /Length 5 0 R
+>>
+stream
+BT
+  /F1 24 Tf
+  72 720 Td
+  (Potato) Tj
+ET
+endstream
+endobj
+
+5 0 obj
+44
+endobj
+
+6 0 obj
+<<
+  /BaseFont /Helvetica
+  /Encoding /WinAnsiEncoding
+  /Name /F1
+  /Subtype /Type1
+  /Type /Font
+>>
+endobj
+
+7 0 obj
+[
+  /PDF
+  /Text
+]
+endobj
+
+8 0 obj
+<<
+  /Length 9 0 R
+  /Filter /Something
+  /DecodeParms 10 0 R
+>>
+stream
+here is some stream data
+endstream
+endobj
+
+9 0 obj
+25
+endobj
+
+10 0 obj
+<<
+  /Length 11 0 R
+>>
+stream
+here is some stream data
+endstream
+endobj
+
+11 0 obj
+25
+endobj
+
+xref
+0 12
+0000000000 65535 f 
+0000000025 00000 n 
+0000000079 00000 n 
+0000000161 00000 n 
+0000000376 00000 n 
+0000000475 00000 n 
+0000000494 00000 n 
+0000000612 00000 n 
+0000000647 00000 n 
+0000000770 00000 n 
+0000000789 00000 n 
+0000000871 00000 n 
+trailer <<
+  /Root 1 0 R
+  /Size 12
+  /QTest 8 0 R
+  /ID [<3e1b045415cfe83fea12b9817e205ef6><3e1b045415cfe83fea12b9817e205ef6>]
+>>
+startxref
+891
+%%EOF