RTF import: fix handling of \objdata

There were two problems here:

1) The input stream is read multiple times, so plain naive XInputStream
is not enough, XSeekable is needed, as it is the case for the stream
provided by the OOXML tokenizer.

2) Seeking to the correct start position is not enough, code using the
stream will assume that seeking to the beginning of the stream allows
reading the correct data again, so provide a dedicated stream instead.

With this, handling of math equations created by Word <= 2007 and
embedded to RTF files can be edited finally.

Change-Id: Ic225e1e1060f8bdd5651a21e68970620c9ac6b68

2 files changed, 63 insertions, 47 deletions

diff --git a/writerfilter/source/rtftok/rtfdocumentimpl.cxx b/writerfilter/source/rtftok/rtfdocumentimpl.cxx
index c74399c79090..d00662375dfc 100644
--- a/writerfilter/source/rtftok/rtfdocumentimpl.cxx
+++ b/writerfilter/source/rtftok/rtfdocumentimpl.cxx
@@ -5349,53 +5349,9 @@ RTFError RTFDocumentImpl::popState()
         if (&m_aStates.top().aDestinationText != m_aStates.top().pDestinationText)
             break; // not for nested group
 
-        m_pObjectData.reset(new SvMemoryStream());
-        int b = 0, count = 2;
-
-        // Feed the destination text to a stream.
-        OString aStr = OUStringToOString(m_aStates.top().pDestinationText->makeStringAndClear(), RTL_TEXTENCODING_ASCII_US);
-        const char* str = aStr.getStr();
-        for (int i = 0; i < aStr.getLength(); ++i)
-        {
-            char ch = str[i];
-            if (ch != 0x0d && ch != 0x0a)
-            {
-                b = b << 4;
-                sal_Int8 parsed = m_pTokenizer->asHex(ch);
-                if (parsed == -1)
-                    return RTFError::HEX_INVALID;
-                b += parsed;
-                count--;
-                if (!count)
-                {
-                    m_pObjectData->WriteChar((char)b);
-                    count = 2;
-                    b = 0;
-                }
-            }
-        }
-
-        if (m_pObjectData->Tell())
-        {
-            m_pObjectData->Seek(0);
-
-            // Skip ObjectHeader
-            sal_uInt32 nData;
-            m_pObjectData->ReadUInt32(nData);   // OLEVersion
-            m_pObjectData->ReadUInt32(nData);   // FormatID
-            m_pObjectData->ReadUInt32(nData);   // ClassName
-            m_pObjectData->SeekRel(nData);
-            m_pObjectData->ReadUInt32(nData);   // TopicName
-            m_pObjectData->SeekRel(nData);
-            m_pObjectData->ReadUInt32(nData);   // ItemName
-            m_pObjectData->SeekRel(nData);
-            m_pObjectData->ReadUInt32(nData);   // NativeDataSize
-        }
-
-        uno::Reference<io::XInputStream> xInputStream(new utl::OInputStreamWrapper(m_pObjectData.get()));
-        auto pStreamValue = std::make_shared<RTFValue>(xInputStream);
-
-        m_aOLEAttributes.set(NS_ooxml::LN_inputstream, pStreamValue);
+        RTFError eError = handleEmbeddedObject();
+        if (eError != RTFError::OK)
+            return eError;
     }
     break;
     case Destination::OBJCLASS:
@@ -6058,6 +6014,64 @@ RTFError RTFDocumentImpl::popState()
     return RTFError::OK;
 }
 
+RTFError RTFDocumentImpl::handleEmbeddedObject()
+{
+    SvMemoryStream aStream;
+    int b = 0, count = 2;
+
+    // Feed the destination text to a stream.
+    OString aStr = OUStringToOString(m_aStates.top().pDestinationText->makeStringAndClear(), RTL_TEXTENCODING_ASCII_US);
+    const char* str = aStr.getStr();
+    for (int i = 0; i < aStr.getLength(); ++i)
+    {
+        char ch = str[i];
+        if (ch != 0x0d && ch != 0x0a)
+        {
+            b = b << 4;
+            sal_Int8 parsed = m_pTokenizer->asHex(ch);
+            if (parsed == -1)
+                return RTFError::HEX_INVALID;
+            b += parsed;
+            count--;
+            if (!count)
+            {
+                aStream.WriteChar(b);
+                count = 2;
+                b = 0;
+            }
+        }
+    }
+
+    // Skip ObjectHeader, see [MS-OLEDS] 2.2.4.
+    if (aStream.Tell())
+    {
+        aStream.Seek(0);
+        sal_uInt32 nData;
+        aStream.ReadUInt32(nData);   // OLEVersion
+        aStream.ReadUInt32(nData);   // FormatID
+        aStream.ReadUInt32(nData);   // ClassName
+        aStream.SeekRel(nData);
+        aStream.ReadUInt32(nData);   // TopicName
+        aStream.SeekRel(nData);
+        aStream.ReadUInt32(nData);   // ItemName
+        aStream.SeekRel(nData);
+        aStream.ReadUInt32(nData);   // NativeDataSize
+
+        if (nData)
+        {
+            m_pObjectData.reset(new SvMemoryStream());
+            m_pObjectData->WriteStream(aStream);
+            m_pObjectData->Seek(0);
+        }
+    }
+
+    uno::Reference<io::XInputStream> xInputStream(new utl::OSeekableInputStreamWrapper(m_pObjectData.get()));
+    auto pStreamValue = std::make_shared<RTFValue>(xInputStream);
+    m_aOLEAttributes.set(NS_ooxml::LN_inputstream, pStreamValue);
+
+    return RTFError::OK;
+}
+
 bool RTFDocumentImpl::isInBackground()
 {
     return m_aStates.top().bInBackground;
diff --git a/writerfilter/source/rtftok/rtfdocumentimpl.hxx b/writerfilter/source/rtftok/rtfdocumentimpl.hxx
index 7112c5833eb6..0af39d3ae98a 100644
--- a/writerfilter/source/rtftok/rtfdocumentimpl.hxx
+++ b/writerfilter/source/rtftok/rtfdocumentimpl.hxx
@@ -439,6 +439,8 @@ private:
     void resetTableRowProperties();
     void backupTableRowProperties();
     void restoreTableRowProperties();
+    /// Turns the destination text into an input stream of the current OLE attributes.
+    RTFError handleEmbeddedObject();
 
     css::uno::Reference<css::uno::XComponentContext> const& m_xContext;
     css::uno::Reference<css::io::XInputStream> const& m_xInputStream;