include/vcl/filter/pdfdocument.hxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
   4  *
   5  * This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8  *
   9  */
  10
  11 #ifndef INCLUDED_VCL_FILTER_PDFDOCUMENT_HXX
  12 #define INCLUDED_VCL_FILTER_PDFDOCUMENT_HXX
  13
  14 #include <memory>
  15 #include <map>
  16 #include <vector>
  17
  18 #include <tools/stream.hxx>
  19
  20 #include <vcl/dllapi.h>
  21
  22 namespace com
  23 {
  24 namespace sun
  25 {
  26 namespace star
  27 {
  28 namespace security
  29 {
  30 class XCertificate;
  31 }
  32 }
  33 }
  34 }
  35
  36 namespace com
  37 {
  38 namespace sun
  39 {
  40 namespace star
  41 {
  42 namespace uno
  43 {
  44 template <class interface_type> class Reference;
  45 }
  46 }
  47 }
  48 }
  49
  50 namespace vcl
  51 {
  52 namespace filter
  53 {
  54 class PDFTrailerElement;
  55 class PDFReferenceElement;
  56 class PDFDocument;
  57 class PDFDictionaryElement;
  58 class PDFArrayElement;
  59 class PDFStreamElement;
  60 class PDFNumberElement;
  61
  62 /// A byte range in a PDF file.
  63 class VCL_DLLPUBLIC PDFElement
  64 {
  65     bool m_bVisiting = false;
  66     bool m_bParsing = false;
  67
  68 public:
  69     PDFElement() = default;
  70     virtual bool Read(SvStream& rStream) = 0;
  71     virtual ~PDFElement() = default;
  72     void setVisiting(bool bVisiting) { m_bVisiting = bVisiting; }
  73     bool alreadyVisiting() const { return m_bVisiting; }
  74     void setParsing(bool bParsing) { m_bParsing = bParsing; }
  75     bool alreadyParsing() const { return m_bParsing; }
  76 };
  77
  78 /// Indirect object: something with a unique ID.
  79 class VCL_DLLPUBLIC PDFObjectElement : public PDFElement
  80 {
  81     /// The document owning this element.
  82     PDFDocument& m_rDoc;
  83     double m_fObjectValue;
  84     double m_fGenerationValue;
  85     std::map<OString, PDFElement*> m_aDictionary;
  86     /// If set, the object contains this number element (outside any dictionary/array).
  87     PDFNumberElement* m_pNumberElement;
  88     /// Position after the '<<' token.
  89     sal_uInt64 m_nDictionaryOffset;
  90     /// Length of the dictionary buffer till (before) the '>>' token.
  91     sal_uInt64 m_nDictionaryLength;
  92     PDFDictionaryElement* m_pDictionaryElement;
  93     /// Position after the '[' token, if m_pArrayElement is set.
  94     sal_uInt64 m_nArrayOffset;
  95     /// Length of the array buffer till (before) the ']' token.
  96     sal_uInt64 m_nArrayLength;
  97     /// The contained direct array, if any.
  98     PDFArrayElement* m_pArrayElement;
  99     /// The stream of this object, used when this is an object stream.
 100     PDFStreamElement* m_pStreamElement;
 101     /// Objects of an object stream.
 102     std::vector<std::unique_ptr<PDFObjectElement>> m_aStoredElements;
 103     /// Elements of an object in an object stream.
 104     std::vector<std::unique_ptr<PDFElement>> m_aElements;
 105     /// Uncompressed buffer of an object in an object stream.
 106     std::unique_ptr<SvMemoryStream> m_pStreamBuffer;
 107     /// List of all reference elements inside this object's dictionary and
 108     /// nested dictionaries.
 109     std::vector<PDFReferenceElement*> m_aDictionaryReferences;
 110
 111 public:
 112     PDFObjectElement(PDFDocument& rDoc, double fObjectValue, double fGenerationValue);
 113     bool Read(SvStream& rStream) override;
 114     PDFElement* Lookup(const OString& rDictionaryKey);
 115     PDFObjectElement* LookupObject(const OString& rDictionaryKey);
 116     double GetObjectValue() const;
 117     void SetDictionaryOffset(sal_uInt64 nDictionaryOffset);
 118     sal_uInt64 GetDictionaryOffset();
 119     void SetDictionaryLength(sal_uInt64 nDictionaryLength);
 120     sal_uInt64 GetDictionaryLength();
 121     PDFDictionaryElement* GetDictionary();
 122     void SetDictionary(PDFDictionaryElement* pDictionaryElement);
 123     void SetNumberElement(PDFNumberElement* pNumberElement);
 124     PDFNumberElement* GetNumberElement() const;
 125     /// Get access to the parsed key-value items from the object dictionary.
 126     const std::map<OString, PDFElement*>& GetDictionaryItems();
 127     const std::vector<PDFReferenceElement*>& GetDictionaryReferences() const;
 128     void AddDictionaryReference(PDFReferenceElement* pReference);
 129     void SetArray(PDFArrayElement* pArrayElement);
 130     void SetStream(PDFStreamElement* pStreamElement);
 131     /// Access to the stream of the object, if it has any.
 132     PDFStreamElement* GetStream() const;
 133     void SetArrayOffset(sal_uInt64 nArrayOffset);
 134     sal_uInt64 GetArrayOffset() const;
 135     void SetArrayLength(sal_uInt64 nArrayLength);
 136     sal_uInt64 GetArrayLength() const;
 137     PDFArrayElement* GetArray() const;
 138     /// Parse objects stored in this object stream.
 139     void ParseStoredObjects();
 140     std::vector<std::unique_ptr<PDFElement>>& GetStoredElements();
 141     SvMemoryStream* GetStreamBuffer() const;
 142     void SetStreamBuffer(std::unique_ptr<SvMemoryStream>& pStreamBuffer);
 143     PDFDocument& GetDocument();
 144 };
 145
 146 /// Array object: a list.
 147 class VCL_DLLPUBLIC PDFArrayElement : public PDFElement
 148 {
 149     std::vector<PDFElement*> m_aElements;
 150     /// The object that contains this array.
 151     PDFObjectElement* const m_pObject;
 152
 153 public:
 154     PDFArrayElement(PDFObjectElement* pObject);
 155     bool Read(SvStream& rStream) override;
 156     void PushBack(PDFElement* pElement);
 157     const std::vector<PDFElement*>& GetElements() const;
 158 };
 159
 160 /// Reference object: something with a unique ID.
 161 class VCL_DLLPUBLIC PDFReferenceElement : public PDFElement
 162 {
 163     PDFDocument& m_rDoc;
 164     int m_fObjectValue;
 165     int m_fGenerationValue;
 166     /// Location after the 'R' token.
 167     sal_uInt64 m_nOffset = 0;
 168     /// The element providing the object number.
 169     PDFNumberElement& m_rObject;
 170
 171 public:
 172     PDFReferenceElement(PDFDocument& rDoc, PDFNumberElement& rObject,
 173                         PDFNumberElement const& rGeneration);
 174     bool Read(SvStream& rStream) override;
 175     /// Assuming the reference points to a number object, return its value.
 176     double LookupNumber(SvStream& rStream) const;
 177     /// Lookup referenced object, without assuming anything about its contents.
 178     PDFObjectElement* LookupObject();
 179     int GetObjectValue() const;
 180     int GetGenerationValue() const;
 181     sal_uInt64 GetOffset() const;
 182     PDFNumberElement& GetObjectElement() const;
 183 };
 184
 185 /// Stream object: a byte array with a known length.
 186 class VCL_DLLPUBLIC PDFStreamElement : public PDFElement
 187 {
 188     size_t const m_nLength;
 189     sal_uInt64 m_nOffset;
 190     /// The byte array itself.
 191     SvMemoryStream m_aMemory;
 192
 193 public:
 194     explicit PDFStreamElement(size_t nLength);
 195     bool Read(SvStream& rStream) override;
 196     sal_uInt64 GetOffset() const;
 197     SvMemoryStream& GetMemory();
 198 };
 199
 200 /// Name object: a key string.
 201 class VCL_DLLPUBLIC PDFNameElement : public PDFElement
 202 {
 203     OString m_aValue;
 204     /// Offset after the '/' token.
 205     sal_uInt64 m_nLocation = 0;
 206
 207 public:
 208     PDFNameElement();
 209     bool Read(SvStream& rStream) override;
 210     const OString& GetValue() const;
 211     sal_uInt64 GetLocation() const;
 212     static sal_uInt64 GetLength() { return 0; }
 213 };
 214
 215 /// Dictionary object: a set key-value pairs.
 216 class VCL_DLLPUBLIC PDFDictionaryElement : public PDFElement
 217 {
 218     /// Key-value pairs when the dictionary is a nested value.
 219     std::map<OString, PDFElement*> m_aItems;
 220     /// Offset after the '<<' token.
 221     sal_uInt64 m_nLocation = 0;
 222     /// Position after the '/' token.
 223     std::map<OString, sal_uInt64> m_aDictionaryKeyOffset;
 224     /// Length of the dictionary key and value, till (before) the next token.
 225     std::map<OString, sal_uInt64> m_aDictionaryKeyValueLength;
 226
 227 public:
 228     PDFDictionaryElement();
 229     bool Read(SvStream& rStream) override;
 230
 231     static size_t Parse(const std::vector<std::unique_ptr<PDFElement>>& rElements,
 232                         PDFElement* pThis, std::map<OString, PDFElement*>& rDictionary);
 233     static PDFElement* Lookup(const std::map<OString, PDFElement*>& rDictionary,
 234                               const OString& rKey);
 235     void SetKeyOffset(const OString& rKey, sal_uInt64 nOffset);
 236     sal_uInt64 GetKeyOffset(const OString& rKey) const;
 237     void SetKeyValueLength(const OString& rKey, sal_uInt64 nLength);
 238     sal_uInt64 GetKeyValueLength(const OString& rKey) const;
 239     const std::map<OString, PDFElement*>& GetItems() const;
 240     /// Looks up an object which is only referenced in this dictionary.
 241     PDFObjectElement* LookupObject(const OString& rDictionaryKey);
 242     /// Looks up an element which is contained in this dictionary.
 243     PDFElement* LookupElement(const OString& rDictionaryKey);
 244 };
 245
 246 enum class TokenizeMode
 247 {
 248     /// Full file.
 249     END_OF_STREAM,
 250     /// Till the first %%EOF token.
 251     EOF_TOKEN,
 252     /// Till the end of the current object.
 253     END_OF_OBJECT,
 254     /// Same as END_OF_OBJECT, but for object streams (no endobj keyword).
 255     STORED_OBJECT
 256 };
 257
 258 /// The type column of an entry in a cross-reference stream.
 259 enum class XRefEntryType
 260 {
 261     /// xref "f" or xref stream "0".
 262     FREE,
 263     /// xref "n" or xref stream "1".
 264     NOT_COMPRESSED,
 265     /// xref stream "2".
 266     COMPRESSED
 267 };
 268
 269 /// An entry in a cross-reference stream.
 270 class XRefEntry
 271 {
 272     XRefEntryType m_eType = XRefEntryType::NOT_COMPRESSED;
 273     /**
 274      * Non-compressed: The byte offset of the object, starting from the
 275      * beginning of the file.
 276      * Compressed: The object number of the object stream in which this object is
 277      * stored.
 278      */
 279     sal_uInt64 m_nOffset = 0;
 280     /// Are changed as part of an incremental update?.
 281     bool m_bDirty = false;
 282
 283 public:
 284     XRefEntry();
 285
 286     void SetType(XRefEntryType eType) { m_eType = eType; }
 287
 288     XRefEntryType GetType() const { return m_eType; }
 289
 290     void SetOffset(sal_uInt64 nOffset) { m_nOffset = nOffset; }
 291
 292     sal_uInt64 GetOffset() const { return m_nOffset; }
 293
 294     void SetDirty(bool bDirty) { m_bDirty = bDirty; }
 295
 296     bool GetDirty() const { return m_bDirty; }
 297 };
 298
 299 /// Hex string: in <AABB> form.
 300 class VCL_DLLPUBLIC PDFHexStringElement : public PDFElement
 301 {
 302     OString m_aValue;
 303
 304 public:
 305     bool Read(SvStream& rStream) override;
 306     const OString& GetValue() const;
 307 };
 308
 309 /// Literal string: in (asdf) form.
 310 class VCL_DLLPUBLIC PDFLiteralStringElement : public PDFElement
 311 {
 312     OString m_aValue;
 313
 314 public:
 315     bool Read(SvStream& rStream) override;
 316     const OString& GetValue() const;
 317 };
 318
 319 /// Numbering object: an integer or a real.
 320 class VCL_DLLPUBLIC PDFNumberElement : public PDFElement
 321 {
 322     /// Input file start location.
 323     sal_uInt64 m_nOffset = 0;
 324     /// Input file token length.
 325     sal_uInt64 m_nLength = 0;
 326     double m_fValue = 0;
 327
 328 public:
 329     PDFNumberElement();
 330     bool Read(SvStream& rStream) override;
 331     double GetValue() const;
 332     sal_uInt64 GetLocation() const;
 333     sal_uInt64 GetLength() const;
 334 };
 335
 336 /**
 337  * In-memory representation of an on-disk PDF document.
 338  *
 339  * The PDF element list is not meant to be saved back to disk, but some
 340  * elements remember their source offset / length, and based on that it's
 341  * possible to modify the input file.
 342  */
 343 class VCL_DLLPUBLIC PDFDocument
 344 {
 345     /// This vector owns all elements.
 346     std::vector<std::unique_ptr<PDFElement>> m_aElements;
 347     /// Object ID <-> object offset map.
 348     std::map<size_t, XRefEntry> m_aXRef;
 349     /// Object offset <-> Object pointer map.
 350     std::map<size_t, PDFObjectElement*> m_aOffsetObjects;
 351     /// Object ID <-> Object pointer map.
 352     std::map<size_t, PDFObjectElement*> m_aIDObjects;
 353     /// List of xref offsets we know.
 354     std::vector<size_t> m_aStartXRefs;
 355     /// Offsets of trailers, from latest to oldest.
 356     std::vector<size_t> m_aTrailerOffsets;
 357     /// Trailer offset <-> Trailer pointer map.
 358     std::map<size_t, PDFTrailerElement*> m_aOffsetTrailers;
 359     /// List of EOF offsets we know.
 360     std::vector<size_t> m_aEOFs;
 361     PDFTrailerElement* m_pTrailer = nullptr;
 362     /// When m_pTrailer is nullptr, this can still have a dictionary.
 363     PDFObjectElement* m_pXRefStream = nullptr;
 364     /// All editing takes place in this buffer, if it happens.
 365     SvMemoryStream m_aEditBuffer;
 366
 367     /// Suggest a minimal, yet free signature ID to use for the next signature.
 368     sal_uInt32 GetNextSignature();
 369     /// Write the signature object as part of signing.
 370     sal_Int32 WriteSignatureObject(const OUString& rDescription, bool bAdES,
 371                                    sal_uInt64& rLastByteRangeOffset, sal_Int64& rContentOffset);
 372     /// Write the appearance object as part of signing.
 373     sal_Int32 WriteAppearanceObject();
 374     /// Write the annot object as part of signing.
 375     sal_Int32 WriteAnnotObject(PDFObjectElement const& rFirstPage, sal_Int32 nSignatureId,
 376                                sal_Int32 nAppearanceId);
 377     /// Write the updated Page object as part of signing.
 378     bool WritePageObject(PDFObjectElement& rFirstPage, sal_Int32 nAnnotId);
 379     /// Write the updated Catalog object as part of signing.
 380     bool WriteCatalogObject(sal_Int32 nAnnotId, PDFReferenceElement*& pRoot);
 381     /// Write the updated cross-references as part of signing.
 382     void WriteXRef(sal_uInt64 nXRefOffset, PDFReferenceElement const* pRoot);
 383
 384 public:
 385     PDFDocument();
 386     PDFDocument& operator=(const PDFDocument&) = delete;
 387     PDFDocument(const PDFDocument&) = delete;
 388     /// @name Low-level functions, to be used by PDFElement subclasses.
 389     //@{
 390     /// Decode a hex dump.
 391     static std::vector<unsigned char> DecodeHexString(PDFHexStringElement const* pElement);
 392     static OString ReadKeyword(SvStream& rStream);
 393     static size_t FindStartXRef(SvStream& rStream);
 394     void ReadXRef(SvStream& rStream);
 395     void ReadXRefStream(SvStream& rStream);
 396     static void SkipWhitespace(SvStream& rStream);
 397     /// Instead of all whitespace, just skip CR and NL characters.
 398     static void SkipLineBreaks(SvStream& rStream);
 399     size_t GetObjectOffset(size_t nIndex) const;
 400     const std::vector<std::unique_ptr<PDFElement>>& GetElements() const;
 401     std::vector<PDFObjectElement*> GetPages();
 402     /// Remember the end location of an EOF token.
 403     void PushBackEOF(size_t nOffset);
 404     /// Look up object based on object number, possibly by parsing object streams.
 405     PDFObjectElement* LookupObject(size_t nObjectNumber);
 406     /// Access to the input document, even after the input stream is gone.
 407     SvMemoryStream& GetEditBuffer();
 408     /// Tokenize elements from current offset.
 409     bool Tokenize(SvStream& rStream, TokenizeMode eMode,
 410                   std::vector<std::unique_ptr<PDFElement>>& rElements,
 411                   PDFObjectElement* pObjectElement);
 412     /// Register an object (owned directly or indirectly by m_aElements) as a provider for a given ID.
 413     void SetIDObject(size_t nID, PDFObjectElement* pObject);
 414     //@}
 415
 416     /// @name High-level functions, to be used by others.
 417     //@{
 418     /// Read elements from the start of the stream till its end.
 419     bool Read(SvStream& rStream);
 420     /// Sign the read document with xCertificate in the edit buffer.
 421     bool Sign(const css::uno::Reference<css::security::XCertificate>& xCertificate,
 422               const OUString& rDescription, bool bAdES);
 423     /// Serializes the contents of the edit buffer.
 424     bool Write(SvStream& rStream);
 425     /// Get a list of signatures embedded into this document.
 426     std::vector<PDFObjectElement*> GetSignatureWidgets();
 427     /// Remove the nth signature from read document in the edit buffer.
 428     bool RemoveSignature(size_t nPosition);
 429     //@}
 430 };
 431
 432 } // namespace pdfio
 433 } // namespace xmlsecurity
 434
 435 #endif // INCLUDED_VCL_FILTER_PDFDOCUMENT_HXX
 436
 437 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */