apt-pkg/tagfile.h

   1 // -*- mode: cpp; mode: fold -*-
   2 // Description                                                          /*{{{*/
   3 // $Id: tagfile.h,v 1.20 2003/05/19 17:13:57 doogie Exp $
   4 /* ######################################################################
   5
   6    Fast scanner for RFC-822 type header information
   7
   8    This parser handles Debian package files (and others). Their form is
   9    RFC-822 type header fields in groups separated by a blank line.
  10
  11    The parser reads the file and provides methods to step linearly
  12    over it or to jump to a pre-recorded start point and read that record.
  13
  14    A second class is used to perform pre-parsing of the record. It works
  15    by indexing the start of each header field and providing lookup
  16    functions for header fields.
  17
  18    ##################################################################### */
  19                                                                         /*}}}*/
  20 #ifndef PKGLIB_TAGFILE_H
  21 #define PKGLIB_TAGFILE_H
  22
  23 #include <apt-pkg/macros.h>
  24
  25 #include <stdio.h>
  26
  27 #include <string>
  28 #include <vector>
  29 #include <list>
  30
  31 #ifndef APT_8_CLEANER_HEADERS
  32 #include <apt-pkg/fileutl.h>
  33 #endif
  34
  35 class FileFd;
  36 class pkgTagSectionPrivate;
  37
  38 class pkgTagSection
  39 {
  40    const char *Section;
  41    // We have a limit of 256 tags per section with the old abi
  42 #if APT_PKG_ABI < 413
  43    APT_DEPRECATED unsigned int Indexes[256];
  44 #endif
  45    unsigned int AlphaIndexes[0x100];
  46 #if APT_PKG_ABI < 413
  47    APT_DEPRECATED unsigned int TagCount;
  48 #endif
  49
  50    // dpointer placeholder (for later in case we need it)
  51    pkgTagSectionPrivate *d;
  52
  53    protected:
  54    const char *Stop;
  55
  56    public:
  57
  58    inline bool operator ==(const pkgTagSection &rhs) {return Section == rhs.Section;};
  59    inline bool operator !=(const pkgTagSection &rhs) {return Section != rhs.Section;};
  60
  61    bool Find(const char *Tag,const char *&Start, const char *&End) const;
  62    bool Find(const char *Tag,unsigned int &Pos) const;
  63    std::string FindS(const char *Tag) const;
  64    signed int FindI(const char *Tag,signed long Default = 0) const;
  65    bool FindB(const char *Tag, bool const &Default = false) const;
  66    unsigned long long FindULL(const char *Tag, unsigned long long const &Default = 0) const;
  67    bool FindFlag(const char *Tag,unsigned long &Flags,
  68                  unsigned long Flag) const;
  69    bool static FindFlag(unsigned long &Flags, unsigned long Flag,
  70                                 const char* Start, const char* Stop);
  71
  72    /** \brief searches the boundaries of the current section
  73     *
  74     * While parameter Start marks the beginning of the section, this method
  75     * will search for the first double newline in the data stream which marks
  76     * the end of the section. It also does a first pass over the content of
  77     * the section parsing it as encountered for processing later on by Find
  78     *
  79     * @param Start is the beginning of the section
  80     * @param MaxLength is the size of valid data in the stream pointed to by Start
  81     * @param Restart if enabled internal state will be cleared, otherwise it is
  82     *  assumed that now more data is available in the stream and the parsing will
  83     *  start were it encountered insufficent data the last time.
  84     *
  85     * @return \b true if section end was found, \b false otherwise.
  86     *  Beware that internal state will be inconsistent if \b false is returned!
  87     */
  88 #if APT_PKG_ABI >= 413
  89    APT_MUSTCHECK bool Scan(const char *Start, unsigned long MaxLength, bool const Restart = true);
  90 #else
  91    APT_MUSTCHECK bool Scan(const char *Start, unsigned long MaxLength, bool const Restart);
  92    APT_MUSTCHECK bool Scan(const char *Start, unsigned long MaxLength);
  93 #endif
  94
  95    inline unsigned long size() const {return Stop - Section;};
  96    void Trim();
  97    virtual void TrimRecord(bool BeforeRecord, const char* &End);
  98
  99    /** \brief amount of Tags in the current section
 100     *
 101     * Note: if a Tag is mentioned repeatly it will be counted multiple
 102     * times, but only the last occurrence is available via Find methods.
 103     */
 104    unsigned int Count() const;
 105 #if APT_PKG_ABI >= 413
 106    bool Exists(const char* const Tag) const;
 107 #else
 108    bool Exists(const char* const Tag);
 109 #endif
 110
 111    void Get(const char *&Start,const char *&Stop,unsigned int I) const;
 112
 113    inline void GetSection(const char *&Start,const char *&Stop) const
 114    {
 115       Start = Section;
 116       Stop = this->Stop;
 117    };
 118
 119    pkgTagSection();
 120    virtual ~pkgTagSection();
 121 };
 122
 123 class pkgTagFilePrivate;
 124 class pkgTagFile
 125 {
 126    pkgTagFilePrivate *d;
 127
 128    APT_HIDDEN bool Fill();
 129    APT_HIDDEN bool Resize();
 130    APT_HIDDEN bool Resize(unsigned long long const newSize);
 131
 132    public:
 133
 134    bool Step(pkgTagSection &Section);
 135    unsigned long Offset();
 136    bool Jump(pkgTagSection &Tag,unsigned long long Offset);
 137
 138    void Init(FileFd *F,unsigned long long Size = 32*1024);
 139
 140    pkgTagFile(FileFd *F,unsigned long long Size = 32*1024);
 141    virtual ~pkgTagFile();
 142 };
 143
 144 /* This is the list of things to rewrite. The rewriter
 145    goes through and changes or adds each of these headers
 146    to suit. A zero forces the header to be erased, an empty string
 147    causes the old value to be used. (rewrite rule ignored) */
 148 struct TFRewriteData
 149 {
 150    const char *Tag;
 151    const char *Rewrite;
 152    const char *NewTag;
 153 };
 154 extern const char **TFRewritePackageOrder;
 155 extern const char **TFRewriteSourceOrder;
 156
 157 bool TFRewrite(FILE *Output,pkgTagSection const &Tags,const char *Order[],
 158                TFRewriteData *Rewrite);
 159
 160 #endif