summaryrefslogtreecommitdiffstats
path: root/apt-pkg/tagfile.h
blob: f6bdd12c9c38c359fab6fcd38f931b9ba15058d7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
// -*- 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;
   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 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