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 #include <stdint.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    unsigned int AlphaIndexes[0x100];
  42
  43    pkgTagSectionPrivate * const d;
  44
  45    protected:
  46    const char *Stop;
  47
  48    public:
  49
  50    inline bool operator ==(const pkgTagSection &rhs) {return Section == rhs.Section;};
  51    inline bool operator !=(const pkgTagSection &rhs) {return Section != rhs.Section;};
  52
  53    bool Find(const char *Tag,const char *&Start, const char *&End) const;
  54    bool Find(const char *Tag,unsigned int &Pos) const;
  55    std::string FindS(const char *Tag) const;
  56    std::string FindRawS(const char *Tag) const;
  57    signed int FindI(const char *Tag,signed long Default = 0) const;
  58    bool FindB(const char *Tag, bool const &Default = false) const;
  59    unsigned long long FindULL(const char *Tag, unsigned long long const &Default = 0) const;
  60    bool FindFlag(const char * const Tag,uint8_t &Flags,
  61                  uint8_t const Flag) const;
  62    bool static FindFlag(uint8_t &Flags, uint8_t const Flag,
  63                                 const char* const Start, const char* const Stop);
  64    bool FindFlag(const char *Tag,unsigned long &Flags,
  65                  unsigned long Flag) const;
  66    bool static FindFlag(unsigned long &Flags, unsigned long Flag,
  67                                 const char* Start, const char* Stop);
  68
  69    /** \brief searches the boundaries of the current section
  70     *
  71     * While parameter Start marks the beginning of the section, this method
  72     * will search for the first double newline in the data stream which marks
  73     * the end of the section. It also does a first pass over the content of
  74     * the section parsing it as encountered for processing later on by Find
  75     *
  76     * @param Start is the beginning of the section
  77     * @param MaxLength is the size of valid data in the stream pointed to by Start
  78     * @param Restart if enabled internal state will be cleared, otherwise it is
  79     *  assumed that now more data is available in the stream and the parsing will
  80     *  start were it encountered insufficent data the last time.
  81     *
  82     * @return \b true if section end was found, \b false otherwise.
  83     *  Beware that internal state will be inconsistent if \b false is returned!
  84     */
  85    APT_MUSTCHECK bool Scan(const char *Start, unsigned long MaxLength, bool const Restart = true);
  86
  87    inline unsigned long size() const {return Stop - Section;};
  88    void Trim();
  89    virtual void TrimRecord(bool BeforeRecord, const char* &End);
  90
  91    /** \brief amount of Tags in the current section
  92     *
  93     * Note: if a Tag is mentioned repeatly it will be counted multiple
  94     * times, but only the last occurrence is available via Find methods.
  95     */
  96    unsigned int Count() const;
  97    bool Exists(const char* const Tag) const;
  98
  99    void Get(const char *&Start,const char *&Stop,unsigned int I) const;
 100
 101    inline void GetSection(const char *&Start,const char *&Stop) const
 102    {
 103       Start = Section;
 104       Stop = this->Stop;
 105    };
 106
 107    pkgTagSection();
 108    virtual ~pkgTagSection();
 109
 110    struct Tag
 111    {
 112       enum ActionType { REMOVE, RENAME, REWRITE } Action;
 113       std::string Name;
 114       std::string Data;
 115
 116       static Tag Remove(std::string const &Name);
 117       static Tag Rename(std::string const &OldName, std::string const &NewName);
 118       static Tag Rewrite(std::string const &Name, std::string const &Data);
 119       private:
 120       Tag(ActionType const Action, std::string const &Name, std::string const &Data) :
 121          Action(Action), Name(Name), Data(Data) {}
 122    };
 123
 124    /** Write this section (with optional rewrites) to a file
 125     *
 126     * @param File to write the section to
 127     * @param Order in which tags should appear in the file
 128     * @param Rewrite is a set of tags to be renamed, rewritten and/or removed
 129     * @return \b true if successful, otherwise \b false
 130     */
 131    bool Write(FileFd &File, char const * const * const Order = NULL, std::vector<Tag> const &Rewrite = std::vector<Tag>()) const;
 132 };
 133
 134
 135 /* For user generated file the parser should be a bit more relaxed in exchange
 136    for being a bit slower to allow comments and new lines all over the place */
 137 class pkgUserTagSection : public pkgTagSection
 138 {
 139    virtual void TrimRecord(bool BeforeRecord, const char* &End) APT_OVERRIDE;
 140 };
 141
 142 class pkgTagFilePrivate;
 143 class pkgTagFile
 144 {
 145    pkgTagFilePrivate * const d;
 146
 147    APT_HIDDEN bool Fill();
 148    APT_HIDDEN bool Resize();
 149    APT_HIDDEN bool Resize(unsigned long long const newSize);
 150
 151    public:
 152
 153    bool Step(pkgTagSection &Section);
 154    unsigned long Offset();
 155    bool Jump(pkgTagSection &Tag,unsigned long long Offset);
 156
 157    void Init(FileFd * const F,unsigned long long const Size = 32*1024);
 158
 159    pkgTagFile(FileFd * const F,unsigned long long Size = 32*1024);
 160    virtual ~pkgTagFile();
 161 };
 162
 163 extern const char **TFRewritePackageOrder;
 164 extern const char **TFRewriteSourceOrder;
 165
 166 // Use pkgTagSection::Tag and pkgTagSection::Write() instead
 167 APT_IGNORE_DEPRECATED_PUSH
 168 struct APT_DEPRECATED TFRewriteData
 169 {
 170    const char *Tag;
 171    const char *Rewrite;
 172    const char *NewTag;
 173 };
 174 APT_DEPRECATED bool TFRewrite(FILE *Output,pkgTagSection const &Tags,const char *Order[],
 175                TFRewriteData *Rewrite);
 176 APT_IGNORE_DEPRECATED_POP
 177
 178 #endif