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Diffstat (limited to 'apt-pkg/tagfile.h')
| -rw-r--r-- | apt-pkg/tagfile.h | 207 |
1 files changed, 207 insertions, 0 deletions
diff --git a/apt-pkg/tagfile.h b/apt-pkg/tagfile.h new file mode 100644 index 0000000..a9f5814 --- /dev/null +++ b/apt-pkg/tagfile.h @@ -0,0 +1,207 @@ +// -*- 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 APT_PUBLIC 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; +#ifdef APT_COMPILING_APT + bool Find(Key key,const char *&Start, const char *&End) const; + bool Find(Key key,unsigned int &Pos) const; + signed int FindI(Key key,signed long Default = 0) const; + bool FindB(Key key, bool Default = false) const; + unsigned long long FindULL(Key key, unsigned long long const &Default = 0) const; + bool FindFlag(Key key,uint8_t &Flags, uint8_t const Flag) const; + bool FindFlag(Key key,unsigned long &Flags, unsigned long Flag) const; + bool Exists(Key key) const; + APT::StringView Find(Key key) const; + APT::StringView FindRaw(Key key) const; +#endif + + 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 APT_PUBLIC 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(); +}; + +APT_PUBLIC extern const char **TFRewritePackageOrder; +APT_PUBLIC extern const char **TFRewriteSourceOrder; + +#endif |