From efbb21673c59cfbf6a74de6866a59cb2dbb8e59f Mon Sep 17 00:00:00 2001
From: Jay Berkenbilt <ejb@ql.org>
Date: Sun, 14 Feb 2021 14:04:40 -0500
Subject: Add functional versions of QPDFObjectHandle::replaceStreamData

Also fix a bug in checking consistency of length for stream data
providers. Length should not be checked or recorded if the provider
says it failed to generate the data.
---
 libqpdf/QPDFObjectHandle.cc | 56 +++++++++++++++++++++++++++++++++++++++++++++
 libqpdf/QPDF_Stream.cc      |  4 ++--
 2 files changed, 58 insertions(+), 2 deletions(-)

(limited to 'libqpdf')

diff --git a/libqpdf/QPDFObjectHandle.cc b/libqpdf/QPDFObjectHandle.cc
index 94875e13..d4796498 100644
--- a/libqpdf/QPDFObjectHandle.cc
+++ b/libqpdf/QPDFObjectHandle.cc
@@ -1347,6 +1347,62 @@ QPDFObjectHandle::replaceStreamData(PointerHolder<StreamDataProvider> provider,
 	provider, filter, decode_parms);
 }
 
+class FunctionProvider: public QPDFObjectHandle::StreamDataProvider
+{
+  public:
+    FunctionProvider(std::function<void(Pipeline*)> provider) :
+        StreamDataProvider(false),
+        p1(provider),
+        p2(nullptr)
+    {
+    }
+    FunctionProvider(std::function<bool(Pipeline*, bool, bool)> provider) :
+        StreamDataProvider(true),
+        p1(nullptr),
+        p2(provider)
+    {
+    }
+
+    virtual void provideStreamData(int, int, Pipeline* pipeline) override
+    {
+        p1(pipeline);
+    }
+
+    virtual bool provideStreamData(int, int, Pipeline* pipeline,
+                                   bool suppress_warnings,
+                                   bool will_retry) override
+    {
+        return p2(pipeline, suppress_warnings, will_retry);
+    }
+
+  private:
+    std::function<void(Pipeline*)> p1;
+    std::function<bool(Pipeline*, bool, bool)> p2;
+};
+
+void
+QPDFObjectHandle::replaceStreamData(std::function<void(Pipeline*)> provider,
+                                    QPDFObjectHandle const& filter,
+                                    QPDFObjectHandle const& decode_parms)
+{
+    assertStream();
+    PointerHolder<StreamDataProvider> sdp = new FunctionProvider(provider);
+    dynamic_cast<QPDF_Stream*>(obj.getPointer())->replaceStreamData(
+	sdp, filter, decode_parms);
+}
+
+void
+QPDFObjectHandle::replaceStreamData(
+    std::function<bool(Pipeline*, bool, bool)> provider,
+    QPDFObjectHandle const& filter,
+    QPDFObjectHandle const& decode_parms)
+{
+    assertStream();
+    PointerHolder<StreamDataProvider> sdp = new FunctionProvider(provider);
+    dynamic_cast<QPDF_Stream*>(obj.getPointer())->replaceStreamData(
+	sdp, filter, decode_parms);
+}
+
 QPDFObjGen
 QPDFObjectHandle::getObjGen() const
 {
diff --git a/libqpdf/QPDF_Stream.cc b/libqpdf/QPDF_Stream.cc
index b05137df..bc3b1b56 100644
--- a/libqpdf/QPDF_Stream.cc
+++ b/libqpdf/QPDF_Stream.cc
@@ -533,7 +533,7 @@ QPDF_Stream::pipeStreamData(Pipeline* pipeline, bool* filterp,
         }
 	qpdf_offset_t actual_length = count.getCount();
 	qpdf_offset_t desired_length = 0;
-        if (this->stream_dict.hasKey("/Length"))
+        if (success && this->stream_dict.hasKey("/Length"))
         {
 	    desired_length = this->stream_dict.getKey("/Length").getIntValue();
             if (actual_length == desired_length)
@@ -555,7 +555,7 @@ QPDF_Stream::pipeStreamData(Pipeline* pipeline, bool* filterp,
                     QUtil::int_to_string(desired_length) + " bytes");
             }
         }
-        else
+        else if (success)
         {
             QTC::TC("qpdf", "QPDF_Stream provider length not provided");
             this->stream_dict.replaceKey(
-- 
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