apt-pkg/tagfile.h

   1 // -*- mode: cpp; mode: fold -*-
   2 // Description                                                          /*{{{*/
   3 /* ######################################################################
   4
   5    Fast scanner for RFC-822 type header information
   6
   7    This parser handles Debian package files (and others). Their form is
   8    RFC-822 type header fields in groups separated by a blank line.
   9
  10    The parser reads the file and provides methods to step linearly
  11    over it or to jump to a pre-recorded start point and read that record.
  12
  13    A second class is used to perform pre-parsing of the record. It works
  14    by indexing the start of each header field and providing lookup
  15    functions for header fields.
  16
  17    ##################################################################### */
  18                                                                         /*}}}*/
  19 #ifndef PKGLIB_TAGFILE_H
  20 #define PKGLIB_TAGFILE_H
  21
  22 #include <apt-pkg/macros.h>
  23
  24 #include <stdio.h>
  25
  26 #include <string>
  27 #include <vector>
  28 #include <list>
  29
  30 #ifndef APT_8_CLEANER_HEADERS
  31 #include <apt-pkg/fileutl.h>
  32 #endif
  33
  34 class FileFd;
  35 class pkgTagSectionPrivate;
  36
  37 class pkgTagSection
  38 {
  39    const char *Section;
  40    unsigned int AlphaIndexes[0x100];
  41
  42    pkgTagSectionPrivate * const d;
  43
  44    protected:
  45    const char *Stop;
  46
  47    public:
  48
  49    inline bool operator ==(const pkgTagSection &rhs) {return Section == rhs.Section;};
  50    inline bool operator !=(const pkgTagSection &rhs) {return Section != rhs.Section;};
  51
  52    bool Find(const char *Tag,const char *&Start, const char *&End) const;
  53    bool Find(const char *Tag,unsigned int &Pos) const;
  54    std::string FindS(const char *Tag) const;
  55    std::string FindRawS(const char *Tag) const;
  56    signed int FindI(const char *Tag,signed long Default = 0) const;
  57    bool FindB(const char *Tag, bool const &Default = false) const;
  58    unsigned long long FindULL(const char *Tag, unsigned long long const &Default = 0) const;
  59    bool FindFlag(const char * const Tag,uint8_t &Flags,
  60                  uint8_t const Flag) const;
  61    bool static FindFlag(uint8_t &Flags, uint8_t const Flag,
  62                                 const char* const Start, const char* const Stop);
  63    bool FindFlag(const char *Tag,unsigned long &Flags,
  64                  unsigned long Flag) const;
  65    bool static FindFlag(unsigned long &Flags, unsigned long Flag,
  66                                 const char* Start, const char* Stop);
  67
  68    /** \brief searches the boundaries of the current section
  69     *
  70     * While parameter Start marks the beginning of the section, this method
  71     * will search for the first double newline in the data stream which marks
  72     * the end of the section. It also does a first pass over the content of
  73     * the section parsing it as encountered for processing later on by Find
  74     *
  75     * @param Start is the beginning of the section
  76     * @param MaxLength is the size of valid data in the stream pointed to by Start
  77     * @param Restart if enabled internal state will be cleared, otherwise it is
  78     *  assumed that now more data is available in the stream and the parsing will
  79     *  start were it encountered insufficent data the last time.
  80     *
  81     * @return \b true if section end was found, \b false otherwise.
  82     *  Beware that internal state will be inconsistent if \b false is returned!
  83     */
  84    APT_MUSTCHECK bool Scan(const char *Start, unsigned long MaxLength, bool const Restart = true);
  85
  86    inline unsigned long size() const {return Stop - Section;};
  87    void Trim();
  88    virtual void TrimRecord(bool BeforeRecord, const char* &End);
  89
  90    /** \brief amount of Tags in the current section
  91     *
  92     * Note: if a Tag is mentioned repeatly it will be counted multiple
  93     * times, but only the last occurrence is available via Find methods.
  94     */
  95    unsigned int Count() const;
  96    bool Exists(const char* const Tag) const;
  97
  98    void Get(const char *&Start,const char *&Stop,unsigned int I) const;
  99
 100    inline void GetSection(const char *&Start,const char *&Stop) const
 101    {
 102       Start = Section;
 103       Stop = this->Stop;
 104    };
 105
 106    pkgTagSection();
 107    virtual ~pkgTagSection();
 108
 109    struct Tag
 110    {
 111       enum ActionType { REMOVE, RENAME, REWRITE } Action;
 112       std::string Name;
 113       std::string Data;
 114
 115       static Tag Remove(std::string const &Name);
 116       static Tag Rename(std::string const &OldName, std::string const &NewName);
 117       static Tag Rewrite(std::string const &Name, std::string const &Data);
 118       private:
 119       Tag(ActionType const Action, std::string const &Name, std::string const &Data) :
 120          Action(Action), Name(Name), Data(Data) {}
 121    };
 122
 123    /** Write this section (with optional rewrites) to a file
 124     *
 125     * @param File to write the section to
 126     * @param Order in which tags should appear in the file
 127     * @param Rewrite is a set of tags to be renamed, rewritten and/or removed
 128     * @return \b true if successful, otherwise \b false
 129     */
 130    bool Write(FileFd &File, char const * const * const Order = NULL, std::vector<Tag> const &Rewrite = std::vector<Tag>()) const;
 131 };
 132
 133
 134 /* For user generated file the parser should be a bit more relaxed in exchange
 135    for being a bit slower to allow comments and new lines all over the place */
 136 class pkgUserTagSection : public pkgTagSection
 137 {
 138    virtual void TrimRecord(bool BeforeRecord, const char* &End) APT_OVERRIDE;
 139 };
 140
 141 class pkgTagFilePrivate;
 142 class pkgTagFile
 143 {
 144    pkgTagFilePrivate * const d;
 145
 146    APT_HIDDEN bool Fill();
 147    APT_HIDDEN bool Resize();
 148    APT_HIDDEN bool Resize(unsigned long long const newSize);
 149
 150    public:
 151
 152    bool Step(pkgTagSection &Section);
 153    unsigned long Offset();
 154    bool Jump(pkgTagSection &Tag,unsigned long long Offset);
 155
 156    void Init(FileFd * const F,unsigned long long const Size = 32*1024);
 157
 158    pkgTagFile(FileFd * const F,unsigned long long Size = 32*1024);
 159    virtual ~pkgTagFile();
 160 };
 161
 162 extern const char **TFRewritePackageOrder;
 163 extern const char **TFRewriteSourceOrder;
 164
 165 // Use pkgTagSection::Tag and pkgTagSection::Write() instead
 166 APT_IGNORE_DEPRECATED_PUSH
 167 struct APT_DEPRECATED TFRewriteData
 168 {
 169    const char *Tag;
 170    const char *Rewrite;
 171    const char *NewTag;
 172 };
 173 APT_DEPRECATED bool TFRewrite(FILE *Output,pkgTagSection const &Tags,const char *Order[],
 174                TFRewriteData *Rewrite);
 175 APT_IGNORE_DEPRECATED_POP
 176
 177 #endif