// -*- mode: cpp; mode: fold -*- // Description /*{{{*/ /* ###################################################################### Fast scanner for RFC-822 type header information This parser handles Debian package files (and others). Their form is RFC-822 type header fields in groups separated by a blank line. The parser reads the file and provides methods to step linearly over it or to jump to a pre-recorded start point and read that record. A second class is used to perform pre-parsing of the record. It works by indexing the start of each header field and providing lookup functions for header fields. ##################################################################### */ /*}}}*/ #ifndef PKGLIB_TAGFILE_H #define PKGLIB_TAGFILE_H #include <apt-pkg/macros.h> #include <stdint.h> #include <stdio.h> #include <list> #include <string> #include <vector> #include <apt-pkg/string_view.h> class FileFd; class pkgTagSectionPrivate; class pkgTagFilePrivate; /** \class pkgTagSection parses a single deb822 stanza and provides various Find methods * to extract the included values. It can also be used to modify and write a * valid deb822 stanza optionally (re)ordering the fields inside the stanza. * * Beware: This class does \b NOT support (#-)comments in in- or output! * If the input contains comments they have to be stripped first like pkgTagFile * does with SUPPORT_COMMENTS flag set. */ class pkgTagSection { const char *Section; unsigned int AlphaIndexes[128]; unsigned int BetaIndexes[128]; pkgTagSectionPrivate * const d; APT_HIDDEN bool FindInternal(unsigned int Pos,const char *&Start, const char *&End) const; APT_HIDDEN APT::StringView FindInternal(unsigned int Pos) const; APT_HIDDEN APT::StringView FindRawInternal(unsigned int Pos) const; APT_HIDDEN signed int FindIInternal(unsigned int Pos,signed long Default = 0) const; APT_HIDDEN bool FindBInternal(unsigned int Pos, bool Default = false) const; APT_HIDDEN unsigned long long FindULLInternal(unsigned int Pos, unsigned long long const &Default = 0) const; APT_HIDDEN bool FindFlagInternal(unsigned int Pos,uint8_t &Flags, uint8_t const Flag) const; APT_HIDDEN bool FindFlagInternal(unsigned int Pos,unsigned long &Flags, unsigned long Flag) const; protected: const char *Stop; public: inline bool operator ==(const pkgTagSection &rhs) {return Section == rhs.Section;}; inline bool operator !=(const pkgTagSection &rhs) {return Section != rhs.Section;}; // TODO: Remove internally std::string FindS(APT::StringView sv) const { return Find(sv).to_string(); } std::string FindRawS(APT::StringView sv) const { return FindRaw(sv).to_string(); }; // Functions for lookup with a perfect hash function enum class Key; APT_HIDDEN bool Find(Key key,const char *&Start, const char *&End) const; APT_HIDDEN bool Find(Key key,unsigned int &Pos) const; APT_HIDDEN signed int FindI(Key key,signed long Default = 0) const; APT_HIDDEN bool FindB(Key key, bool Default = false) const; APT_HIDDEN unsigned long long FindULL(Key key, unsigned long long const &Default = 0) const; APT_HIDDEN bool FindFlag(Key key,uint8_t &Flags, uint8_t const Flag) const; APT_HIDDEN bool FindFlag(Key key,unsigned long &Flags, unsigned long Flag) const; APT_HIDDEN bool Exists(Key key) const; APT_HIDDEN APT::StringView Find(Key key) const; APT_HIDDEN APT::StringView FindRaw(Key key) const; bool Find(APT::StringView Tag,const char *&Start, const char *&End) const; bool Find(APT::StringView Tag,unsigned int &Pos) const; APT::StringView Find(APT::StringView Tag) const; APT::StringView FindRaw(APT::StringView Tag) const; signed int FindI(APT::StringView Tag,signed long Default = 0) const; bool FindB(APT::StringView, bool Default = false) const; unsigned long long FindULL(APT::StringView Tag, unsigned long long const &Default = 0) const; bool FindFlag(APT::StringView Tag,uint8_t &Flags, uint8_t const Flag) const; bool FindFlag(APT::StringView Tag,unsigned long &Flags, unsigned long Flag) const; bool Exists(APT::StringView Tag) const; bool static FindFlag(uint8_t &Flags, uint8_t const Flag, const char* const Start, const char* const Stop); bool static FindFlag(unsigned long &Flags, unsigned long Flag, const char* Start, const char* Stop); /** \brief searches the boundaries of the current section * * While parameter Start marks the beginning of the section, this method * will search for the first double newline in the data stream which marks * the end of the section. It also does a first pass over the content of * the section parsing it as encountered for processing later on by Find * * @param Start is the beginning of the section * @param MaxLength is the size of valid data in the stream pointed to by Start * @param Restart if enabled internal state will be cleared, otherwise it is * assumed that now more data is available in the stream and the parsing will * start were it encountered insufficient data the last time. * * @return \b true if section end was found, \b false otherwise. * Beware that internal state will be inconsistent if \b false is returned! */ APT_MUSTCHECK bool Scan(const char *Start, unsigned long MaxLength, bool const Restart = true); inline unsigned long size() const {return Stop - Section;}; void Trim(); virtual void TrimRecord(bool BeforeRecord, const char* &End); /** \brief amount of Tags in the current section * * Note: if a Tag is mentioned repeatedly it will be counted multiple * times, but only the last occurrence is available via Find methods. */ unsigned int Count() const; void Get(const char *&Start,const char *&Stop,unsigned int I) const; inline void GetSection(const char *&Start,const char *&Stop) const { Start = Section; Stop = this->Stop; }; pkgTagSection(); virtual ~pkgTagSection(); struct Tag { enum ActionType { REMOVE, RENAME, REWRITE } Action; std::string Name; std::string Data; static Tag Remove(std::string const &Name); static Tag Rename(std::string const &OldName, std::string const &NewName); static Tag Rewrite(std::string const &Name, std::string const &Data); private: Tag(ActionType const Action, std::string const &Name, std::string const &Data) : Action(Action), Name(Name), Data(Data) {} }; /** Write this section (with optional rewrites) to a file * * @param File to write the section to * @param Order in which tags should appear in the file * @param Rewrite is a set of tags to be renamed, rewritten and/or removed * @return \b true if successful, otherwise \b false */ bool Write(FileFd &File, char const * const * const Order = NULL, std::vector<Tag> const &Rewrite = std::vector<Tag>()) const; }; /** \class pkgTagFile reads and prepares a deb822 formatted file for parsing * via #pkgTagSection. The default mode tries to be as fast as possible and * assumes perfectly valid (machine generated) files like Packages. Support * for comments e.g. needs to be enabled explicitly. */ class pkgTagFile { pkgTagFilePrivate * const d; APT_HIDDEN bool Fill(); APT_HIDDEN bool Resize(); APT_HIDDEN bool Resize(unsigned long long const newSize); public: bool Step(pkgTagSection &Section); unsigned long Offset(); bool Jump(pkgTagSection &Tag,unsigned long long Offset); enum Flags { STRICT = 0, SUPPORT_COMMENTS = 1 << 0, }; void Init(FileFd * const F, pkgTagFile::Flags const Flags, unsigned long long Size = 32*1024); void Init(FileFd * const F,unsigned long long const Size = 32*1024); pkgTagFile(FileFd * const F, pkgTagFile::Flags const Flags, unsigned long long Size = 32*1024); pkgTagFile(FileFd * const F,unsigned long long Size = 32*1024); virtual ~pkgTagFile(); }; extern const char **TFRewritePackageOrder; extern const char **TFRewriteSourceOrder; #endif