pdf: add writeString for pdf elements for writing element content

This adds a writeString virtual method to PDFElement and
subclasses and implemnts them for each element. This is used to
write the PDF object hierarchy back to a string buffer.

Change-Id: I484c9cebd8ab9149029b925a47e68b6a4fdf9be1
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/105492
Tested-by: Jenkins
Reviewed-by: Tomaž Vajngerl <quikee@gmail.com>
(cherry picked from commit fbf14b4e48c7677d5acf9a0ab91a3dc8d4ffc6fd)
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/105778
Tested-by: Jenkins CollaboraOffice <jenkinscollaboraoffice@gmail.com>
Reviewed-by: Andras Timar <andras.timar@collabora.com>

2 files changed, 92 insertions, 3 deletions

diff --git a/include/vcl/filter/pdfdocument.hxx b/include/vcl/filter/pdfdocument.hxx
index 5ab6c2044ac8..b1cf34856a95 100644
--- a/include/vcl/filter/pdfdocument.hxx
+++ b/include/vcl/filter/pdfdocument.hxx
@@ -17,6 +17,7 @@
 
 #include <tools/stream.hxx>
 #include <vcl/dllapi.h>
+#include <rtl/strbuf.hxx>
 
 #include <vcl/filter/pdfobjectcontainer.hxx>
 
@@ -79,6 +80,8 @@ public:
     bool alreadyVisiting() const { return m_bVisiting; }
     void setParsing(bool bParsing) { m_bParsing = bParsing; }
     bool alreadyParsing() const { return m_bParsing; }
+
+    virtual void writeString(OStringBuffer& rBuffer) = 0;
 };
 
 /// Indirect object: something with a unique ID.
@@ -149,6 +152,8 @@ public:
     SvMemoryStream* GetStreamBuffer() const;
     void SetStreamBuffer(std::unique_ptr<SvMemoryStream>& pStreamBuffer);
     PDFDocument& GetDocument();
+
+    void writeString(OStringBuffer& /*rBuffer*/) override { assert(false && "not implemented"); }
 };
 
 /// Array object: a list.
@@ -163,6 +168,17 @@ public:
     bool Read(SvStream& rStream) override;
     void PushBack(PDFElement* pElement);
     const std::vector<PDFElement*>& GetElements() const;
+
+    void writeString(OStringBuffer& rBuffer) override
+    {
+        rBuffer.append("[ ");
+        for (auto& rElement : m_aElements)
+        {
+            rElement->writeString(rBuffer);
+            rBuffer.append(" ");
+        }
+        rBuffer.append("]");
+    }
 };
 
 /// Reference object: something with a unique ID.
@@ -188,6 +204,14 @@ public:
     int GetGenerationValue() const;
     sal_uInt64 GetOffset() const;
     PDFNumberElement& GetObjectElement() const;
+
+    void writeString(OStringBuffer& rBuffer) override
+    {
+        rBuffer.append(sal_Int32(GetObjectValue()));
+        rBuffer.append(' ');
+        rBuffer.append(sal_Int32(GetGenerationValue()));
+        rBuffer.append(" R");
+    }
 };
 
 /// Stream object: a byte array with a known length.
@@ -203,6 +227,13 @@ public:
     bool Read(SvStream& rStream) override;
     sal_uInt64 GetOffset() const;
     SvMemoryStream& GetMemory();
+
+    void writeString(OStringBuffer& rBuffer) override
+    {
+        rBuffer.append("stream\n");
+        rBuffer.append(static_cast<const char*>(m_aMemory.GetData()), m_aMemory.GetSize());
+        rBuffer.append("\nendstream\n");
+    }
 };
 
 /// Name object: a key string.
@@ -218,6 +249,12 @@ public:
     const OString& GetValue() const;
     sal_uInt64 GetLocation() const;
     static sal_uInt64 GetLength() { return 0; }
+
+    void writeString(OStringBuffer& rBuffer) override
+    {
+        rBuffer.append("/");
+        rBuffer.append(m_aValue);
+    }
 };
 
 /// Dictionary object: a set key-value pairs.
@@ -249,6 +286,20 @@ public:
     PDFObjectElement* LookupObject(const OString& rDictionaryKey);
     /// Looks up an element which is contained in this dictionary.
     PDFElement* LookupElement(const OString& rDictionaryKey);
+
+    void writeString(OStringBuffer& rBuffer) override
+    {
+        rBuffer.append("<< ");
+        for (auto& rPair : m_aItems)
+        {
+            rBuffer.append("/");
+            rBuffer.append(rPair.first);
+            rBuffer.append(" ");
+            rPair.second->writeString(rBuffer);
+            rBuffer.append(" ");
+        }
+        rBuffer.append(">>");
+    }
 };
 
 enum class TokenizeMode
@@ -312,6 +363,13 @@ class VCL_DLLPUBLIC PDFHexStringElement final : public PDFElement
 public:
     bool Read(SvStream& rStream) override;
     const OString& GetValue() const;
+
+    void writeString(OStringBuffer& rBuffer) override
+    {
+        rBuffer.append("<");
+        rBuffer.append(m_aValue);
+        rBuffer.append(">");
+    }
 };
 
 /// Literal string: in (asdf) form.
@@ -322,6 +380,13 @@ class VCL_DLLPUBLIC PDFLiteralStringElement final : public PDFElement
 public:
     bool Read(SvStream& rStream) override;
     const OString& GetValue() const;
+
+    void writeString(OStringBuffer& rBuffer) override
+    {
+        rBuffer.append("(");
+        rBuffer.append(m_aValue);
+        rBuffer.append(")");
+    }
 };
 
 /// Numbering object: an integer or a real.
@@ -339,6 +404,8 @@ public:
     double GetValue() const;
     sal_uInt64 GetLocation() const;
     sal_uInt64 GetLength() const;
+
+    void writeString(OStringBuffer& rBuffer) override { rBuffer.append(m_fValue); }
 };
 
 /**
diff --git a/vcl/source/filter/ipdf/pdfdocument.cxx b/vcl/source/filter/ipdf/pdfdocument.cxx
index cf3a0ea430b0..f83d1614364e 100644
--- a/vcl/source/filter/ipdf/pdfdocument.cxx
+++ b/vcl/source/filter/ipdf/pdfdocument.cxx
@@ -49,6 +49,7 @@ class PDFCommentElement : public PDFElement
 public:
     explicit PDFCommentElement(PDFDocument& rDoc);
     bool Read(SvStream& rStream) override;
+    void writeString(OStringBuffer& /*rBuffer*/) override {}
 };
 
 class PDFReferenceElement;
@@ -63,6 +64,8 @@ public:
     PDFEndDictionaryElement();
     bool Read(SvStream& rStream) override;
     sal_uInt64 GetLocation() const;
+
+    void writeString(OStringBuffer& /*rBuffer*/) override {}
 };
 
 /// End of a stream: 'endstream' keyword.
@@ -70,6 +73,8 @@ class PDFEndStreamElement : public PDFElement
 {
 public:
     bool Read(SvStream& rStream) override;
+
+    void writeString(OStringBuffer& /*rBuffer*/) override {}
 };
 
 /// End of an object: 'endobj' keyword.
@@ -77,6 +82,8 @@ class PDFEndObjectElement : public PDFElement
 {
 public:
     bool Read(SvStream& rStream) override;
+
+    void writeString(OStringBuffer& /*rBuffer*/) override {}
 };
 
 /// End of an array: ']'.
@@ -89,14 +96,27 @@ public:
     PDFEndArrayElement();
     bool Read(SvStream& rStream) override;
     sal_uInt64 GetOffset() const;
+
+    void writeString(OStringBuffer& /*rBuffer*/) override {}
 };
 
 /// Boolean object: a 'true' or a 'false'.
 class PDFBooleanElement : public PDFElement
 {
+    bool m_aValue;
+
 public:
-    explicit PDFBooleanElement(bool bValue);
+    explicit PDFBooleanElement(bool bValue)
+        : m_aValue(bValue)
+    {
+    }
+
     bool Read(SvStream& rStream) override;
+
+    void writeString(OStringBuffer& rBuffer) override
+    {
+        rBuffer.append(m_aValue ? "true" : "false");
+    }
 };
 
 /// Null object: the 'null' singleton.
@@ -104,6 +124,8 @@ class PDFNullElement : public PDFElement
 {
 public:
     bool Read(SvStream& rStream) override;
+
+    void writeString(OStringBuffer& rBuffer) override { rBuffer.append("null"); }
 };
 
 /// The trailer singleton is at the end of the doc.
@@ -119,6 +141,8 @@ public:
     bool Read(SvStream& rStream) override;
     PDFElement* Lookup(const OString& rDictionaryKey);
     sal_uInt64 GetLocation() const;
+
+    void writeString(OStringBuffer& /*rBuffer*/) override {}
 };
 
 XRefEntry::XRefEntry() = default;
@@ -2212,8 +2236,6 @@ sal_uInt64 PDFNumberElement::GetLocation() const { return m_nOffset; }
 
 sal_uInt64 PDFNumberElement::GetLength() const { return m_nLength; }
 
-PDFBooleanElement::PDFBooleanElement(bool /*bValue*/) {}
-
 bool PDFBooleanElement::Read(SvStream& /*rStream*/) { return true; }
 
 bool PDFNullElement::Read(SvStream& /*rStream*/) { return true; }