FS_IndexFile.h

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/*
 * PROPRIETARY INFORMATION.  This software is proprietary to
 * Side Effects Software Inc., and is not to be reproduced,
 * transmitted, or disclosed in any way without written permission.
 *
 * NAME:        FS_IndexFile.h ( FS Library, C++)
 *
 * COMMENTS:
 *
 */

#ifndef __FS_IndexFile__
#define __FS_IndexFile__

#include "FS_API.h"

#include <UT/UT_ArrayStringMap.h>
#include <UT/UT_Defines.h>
#include <UT/UT_Lock.h>
#include <UT/UT_SharedPtr.h>
#include <UT/UT_StringHolder.h>
#include <UT/UT_ValArray.h>
#include <UT/UT_VectorTypes.h>
#include <SYS/SYS_Types.h>
#include <iosfwd>
#include <time.h>

class FS_IndexFileHandle;
class FS_IStreamFilterFactory;
class FS_Reader;
class FS_ReaderStream;
class FS_Section;
class FS_WriteFilterFactory;
class UT_Options;
class UT_String;
class UT_WorkBuffer;

#define FS_SECTION_SEPARATOR            UT_SECTION_SEPARATOR_CHAR
#define FS_SECTION_SEPARATOR_STRING     UT_SECTION_SEPARATOR_STRING
#define FS_SECTIONFILE                  "Sections.list"

// This class implements a file that contains several sections that can be found
// at certain offsets of a main file.
class FS_API FS_IndexFile
{
public:
    /// Default constructor.
    FS_IndexFile();

    /// This constructor takes a path of some sort (e.g. a file path, an oplib:
    /// path, an opdef: path, an http:// path, etc) to the index file.
    FS_IndexFile(const char *source);

    /// This constructor takes a reader that will be used to retrieve section
    /// data. The index file takes ownership and will delete the reader in the
    /// destructor.  (If null is passed in, this object creates its own default
    /// FS_Reader, but unless a source is given nothing can be read from such
    /// an index file.)
    ///
    /// If no source is given, closing the index file and reopening it again
    /// will have no effect on the underlying reader.  The reader will only be
    /// closed and deleted when the index file object is deleted.  If a source
    /// is passed in, though, the reader will be deleted when the index file is
    /// closed and subsequent openings will use the source path to construct a
    /// new reader.
    FS_IndexFile(FS_Reader *reader, const char *source=nullptr);

    virtual ~FS_IndexFile();

    // Some basic operations on sections (add, remove, modify).
    // These functions don't affect the source file. The changes
    // are only evident when we call writeFile.
    // Reading is NOT currently threadsafe.
    inline bool  hasSection(const UT_StringRef &section) const
                    { return mySectionTable.contains(section) ||
                             myTempSectionTable.contains(section); }
    inline bool  hasTempSection(const UT_StringRef &section) const
                    { return myTempSectionTable.contains(section); }
    inline bool  hasRegularSection(const UT_StringRef &section) const
                    { return mySectionTable.contains(section); }
    time_t       getSectionModTime(const UT_StringRef &section) const;
    int          getSectionDataSize(const UT_StringRef &section) const;
    bool         readSection(const UT_StringRef &section,
                             char *buffer) const;
    bool         readSection(const UT_StringRef &section,
                             UT_WorkBuffer &buffer) const;
    bool         readOptionsSection(const UT_StringRef &section,
                                    UT_Options &options) const;
    void         addSection(const UT_StringRef &section,
                            const char *filename);
    void         addSection(const UT_StringRef &section,
                            const UT_WorkBuffer &buf,
                            time_t modtime = time_t(-1));
    void         addSection(const UT_StringRef &section,
                            const char *buffer,
                            int len, time_t modtime = time_t(-1));
    void         addSection(const UT_StringRef &section,
                            const FS_IndexFile &file);
    void         modifySection(const UT_StringRef &section,
                               const char *buffer,
                               int len, time_t modtime = time_t(-1));
    void         modifySection(const UT_StringRef &section,
                               const UT_WorkBuffer &buf,
                               time_t modtime = time_t(-1));
    void         removeSection(const UT_StringRef &section);
    void         mergeIndexFile(const FS_IndexFile &file, bool overwrite);

    // Change the ordering of some sections. This is basically a book-keeping
    // change, and only affects things when this index file is then saved.
    void         moveSections(int first, int last, int offset);

    // Get the modification time for the index file as a whole.
    time_t       getModTime() const;

    // Get the size of the whole index file
    int64        getFileDataSize() const;

    // Sets the stream filters used for processing the data when it is read
    // in or written out.
    void         setFilters(FS_WriteFilterFactory *encrypt_factory,
                            FS_IStreamFilterFactory *decrypt_factory);

    // Gets the decryption and encryption filter factories.
    FS_WriteFilterFactory       *getEncryptionFilter() const;
    FS_IStreamFilterFactory     *getDecryptionFilter() const;

    // Get an opaque pointer to a section.
    FS_Section          *getSection(const UT_StringRef &section) const;

    // Get an FS_Reader for reading a section of the index.
    FS_Reader           *getSectionReader(const UT_StringRef &section) const;

    // These utility functions should only be used by FS_ReaderHelpers
    FS_ReaderStream     *getSectionStream(const UT_StringRef &section) const;
    FS_ReaderStream     *getStreamCopy() const;

    // Given an opaque section pointer get an FS_IndexFile it represents.
    FS_IndexFileHandle   getIndexFileFromSection(const UT_StringRef &section,
                                                 const char *source = nullptr) const;

    // Simple access functions to find out about our sections.
    int                  getNumSections() const;
    const UT_StringHolder &getSectionName(int index) const;

    // Access our source file name (which may be empty).
    const UT_StringHolder &getSourceFile() const { return mySourceFile; }

    // Access functions for our description string.
    const UT_StringHolder &getDescription() const;
    void                   setDescription(const UT_StringHolder &description);
  

    // If we are going to be written to a strstream, this function returns
    // a sensible guess about the buffer size that should be allocated.
    exint                guessStreamSize() const;

    // Write us out to a stream (with all modifications).
    // Note: Don't write out an index file to the same file it was loaded
    // from, since writing implicitly reads the file. Instead, write it to a
    // separate file and then copy it over. This will also require this index
    // file to be reloaded.
    virtual void         writeFile(std::ostream &os) const;

    // This functions are for expanding and collapsing an index file,
    // much like hexpand and hcollapse do for cpio archives.
    virtual bool         expandToDirectory(const char *destdir);
    virtual bool         collapseFromDirectory(const char *srcdir);

    // Get the current time, used to set the section modification time.
    static time_t        getCurrentTime()
                         {
                             time_t currtime;
                             return ::time(&currtime);
                         }

    /// Tests if the index file is copy-protected.
    bool                 isCopyProtected() const;

    /// Tests if the index file is black boxed.
    bool                 isBlackBoxed() const;

    /// Tests if the index file is stored as expanded.
    bool                 isExpanded() const
                            { return myIsExpanded; }

    static bool          canWriteFile(const char *filename);

    bool                 getSectionFileName(const char *section,
                                            UT_String &filename);

    static void          clearStartupCache();

    // -----------------------------------------------------------------------
    // Section data conversion to/from text

    typedef bool(*ConvertFunc)(const UT_StringHolder &src_path,
                               const UT_WorkBuffer &in_data,
                               UT_WorkBuffer &out_data);

    struct ConversionFuncs
    {
        ConversionFuncs(const char *bin_file_pattern = "",
                        const char *text_file_pattern = "",
                        ConvertFunc to_text = nullptr,
                        ConvertFunc from_text = nullptr)
            : myToText(to_text),
              myFromText(from_text),
              myBinFilePattern(bin_file_pattern),
              myTextFilePattern(text_file_pattern)
        {}

        void clear()
        {
            myToText = nullptr;
            myFromText = nullptr;
            myBinFilePattern.clear();
            myTextFilePattern.clear();
        }

        bool isClear() const
        {
            // sufficient to just text first data member
            return myToText == nullptr;
        }

        ConvertFunc              myToText;
        ConvertFunc              myFromText;
        UT_StringHolder          myBinFilePattern;
        UT_StringHolder          myTextFilePattern;
    };
    typedef UT_ArrayStringMap<ConversionFuncs> ConversionList;


    static bool  registerConversionFuncs(const char *bin_file_pattern,
                                         const char *text_file_pattern,
                                         ConvertFunc to_text,
                                         ConvertFunc from_text);

    static const ConversionList &getConversionsToText();
    static const ConversionList &getConversionsFromText();


protected:
    void                 setModified() { myModified = true; }

    exint                writeHeader(std::ostream &os,
                                     const UT_Int32Array &section_sizes) const;

    static ConversionList &_getConversionsToText();
    static ConversionList &_getConversionsFromText();

    mutable UT_Lock              myLock;

private:
    typedef UT_ValArray<FS_Section *> FS_SectionArray;

    // Functions for opening and closing our stream.
    void                 openStream(const UT_Options *options = nullptr) const;
    void                 closeStream() const;

    // Helper functions for reading and writing ourselves to a directory.
    static void          makeValidFileName(UT_String &filename);
    bool                 writeSectionListFile(const char *sectionfile);

    // Writes out a section to the output stream. If the filter factory
    // has been set, the filter will be applied to the section data before
    // it is written out.
    void writeSection(FS_Section *section,
                      std::ostream &os,
                      bool as_text) const;

    // Get an FS_Reader for reading a section of the index.
    FS_Reader           *getSectionReader(FS_Section *section) const;

    // These utility functions should only be used by FS_ReaderHelpers
    FS_ReaderStream     *getSectionStream(FS_Section *section) const;

    // Read in our index and use it to create our section data structures.
    void                 readIndex();
    void                 readDirectoryIndex(
                                    const UT_String &source_file_path,
                                    const UT_String &sections_file_path);
    void                 readStreamIndex();

    // Obtains a size of the i-th section after it has been filtered (if at all)
    int                  getWriteFilteredSectionSize( int index ) const;

    // Recalculates the data sizes of our sections when the read filter is set.
    void                 recalculateFilteredSectionSizes();

    using SectionMap = UT_ArrayStringMap<FS_Section*>;

    // Data:
    mutable FS_Reader           *myReader;
    FS_SectionArray              mySections;
    SectionMap                   mySectionTable;
    FS_SectionArray              myTempSections;
    SectionMap                   myTempSectionTable;
    UT_StringHolder              myDescription;
    UT_StringHolder              mySourceFile;
    FS_WriteFilterFactory       *myWriteFilter;
    FS_IStreamFilterFactory     *myReadFilter;
    time_t                       myModTime;
    int64                        mySize;
    int                          myStreamStart;
    bool                         myModified;
    bool                         myIsExpanded;

    friend class FS_Section;
    friend class FS_EmbeddedSection;
    friend class FS_DiskSection;
    friend class FS_IndexFileHandle;
};

class FS_API FS_IndexFileHandle : public UT_SharedPtr<FS_IndexFile>
{
public:
    FS_IndexFileHandle();
    FS_IndexFileHandle(FS_IndexFile *);
    virtual ~FS_IndexFileHandle();

    // FIXME:TODO:XXX: This is highly suspicious because we have a non-trivial
    // destructor. But making this explicit for now for rule of three without
    // any behaviour changes.
    FS_IndexFileHandle(const FS_IndexFileHandle &src) = default;
    FS_IndexFileHandle &operator=(const FS_IndexFileHandle &src) = default;

private:

    friend class FS_Section;
    friend class FS_EmbeddedSection;
    friend class FS_DiskSection;
    friend class FS_IndexFile;
};

// For UT::ArraySet.
namespace UT
{
template <typename T>
struct DefaultClearer;

template <>
struct DefaultClearer<FS_IndexFile::ConversionFuncs>
{
    using ValueT = FS_IndexFile::ConversionFuncs;
    static void clear(ValueT &v) { v.clear(); }
    static bool isClear(const ValueT &v) { return v.isClear(); }
    static void clearConstruct(ValueT *p)
    {
        new ((void *)p) ValueT();
    }
    static const bool clearNeedsDestruction = false;
};
} // namespace UT

#endif