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apt/apt-pkg/tagfile.h

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// -*- 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
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