apt-pkg/pkgcache.h

   1 // -*- mode: cpp; mode: fold -*-
   2 // Description                                                          /*{{{*/
   3 /**\file pkgcache.h
   4    \brief pkgCache - Structure definitions for the cache file
   5
   6    The goal of the cache file is two fold:
   7    Firstly to speed loading and processing of the package file array and
   8    secondly to reduce memory consumption of the package file array.
   9
  10    The implementation is aimed at an environment with many primary package
  11    files, for instance someone that has a Package file for their CD-ROM, a
  12    Package file for the latest version of the distribution on the CD-ROM and a
  13    package file for the development version. Always present is the information
  14    contained in the status file which might be considered a separate package
  15    file.
  16
  17    Please understand, this is designed as a <b>Cache file</b> it is not meant to be
  18    used on any system other than the one it was created for. It is not meant to
  19    be authoritative either, i.e. if a system crash or software failure occurs it
  20    must be perfectly acceptable for the cache file to be in an inconsistent
  21    state. Furthermore at any time the cache file may be erased without losing
  22    any information.
  23
  24    Also the structures and storage layout is optimized for use by the APT
  25    and may not be suitable for all purposes. However it should be possible
  26    to extend it with associate cache files that contain other information.
  27
  28    To keep memory use down the cache file only contains often used fields and
  29    fields that are inexpensive to store, the Package file has a full list of
  30    fields. Also the client may assume that all items are perfectly valid and
  31    need not perform checks against their correctness. Removal of information
  32    from the cache is possible, but blanks will be left in the file, and
  33    unused strings will also be present. The recommended implementation is to
  34    simply rebuild the cache each time any of the data files change. It is
  35    possible to add a new package file to the cache without any negative side
  36    effects.
  37
  38    <b>Note on Pointer access</b>
  39    Clients should always use the CacheIterators classes for access to the
  40    cache and the data in it. They also provide a simple STL-like method for
  41    traversing the links of the datastructure.
  42
  43    Every item in every structure is stored as the index to that structure.
  44    What this means is that once the files is mmaped every data access has to
  45    go through a fix up stage to get a real memory pointer. This is done
  46    by taking the index, multiplying it by the type size and then adding
  47    it to the start address of the memory block. This sounds complex, but
  48    in C it is a single array dereference. Because all items are aligned to
  49    their size and indexes are stored as multiples of the size of the structure
  50    the format is immediately portable to all possible architectures - BUT the
  51    generated files are -NOT-.
  52
  53    This scheme allows code like this to be written:
  54    <example>
  55      void *Map = mmap(...);
  56      Package *PkgList = (Package *)Map;
  57      Header *Head = (Header *)Map;
  58      char *Strings = (char *)Map;
  59      cout << (Strings + PkgList[Head->HashTable[0]]->Name) << endl;
  60    </example>
  61    Notice the lack of casting or multiplication. The net result is to return
  62    the name of the first package in the first hash bucket, without error
  63    checks.
  64
  65    The generator uses allocation pools to group similarly sized structures in
  66    large blocks to eliminate any alignment overhead. The generator also
  67    assures that no structures overlap and all indexes are unique. Although
  68    at first glance it may seem like there is the potential for two structures
  69    to exist at the same point the generator never allows this to happen.
  70    (See the discussion of free space pools)
  71
  72    See \ref pkgcachegen.h for more information about generating cache structures. */
  73                                                                         /*}}}*/
  74 #ifndef PKGLIB_PKGCACHE_H
  75 #define PKGLIB_PKGCACHE_H
  76
  77 #include <apt-pkg/mmap.h>
  78 #include <apt-pkg/macros.h>
  79
  80 #include <string>
  81 #include <time.h>
  82 #include <stdint.h>
  83
  84 #ifndef APT_8_CLEANER_HEADERS
  85 using std::string;
  86 #endif
  87
  88 #if APT_PKG_ABI >= 413
  89 // storing file sizes of indexes, which are way below 4 GB for now
  90 typedef uint32_t map_filesize_t;
  91 typedef map_filesize_t should_be_map_filesize_t;
  92 #else
  93 typedef unsigned long map_filesize_t;
  94 typedef unsigned int should_be_map_filesize_t;
  95 #endif
  96 #if APT_PKG_ABI >= 413
  97 // each package/group/dependency gets an id
  98 typedef uint32_t map_id_t;
  99 typedef map_id_t should_be_map_id_t;
 100 #else
 101 typedef unsigned long map_id_t;
 102 typedef unsigned int should_be_map_id_t;
 103 #endif
 104 #if APT_PKG_ABI >= 413
 105 // some files get an id, too, but in far less absolute numbers
 106 typedef uint16_t map_fileid_t;
 107 typedef map_fileid_t should_be_map_fileid_t;
 108 #else
 109 typedef unsigned long map_fileid_t;
 110 typedef unsigned int should_be_map_fileid_t;
 111 #endif
 112 #if APT_PKG_ABI >= 413
 113 // relative pointer from cache start
 114 typedef uint32_t map_pointer_t;
 115 #else
 116 typedef unsigned int map_pointer_t;
 117 #endif
 118 // same as the previous, but documented to be to a string item
 119 typedef map_pointer_t map_stringitem_t;
 120 #if APT_PKG_ABI >= 413
 121 typedef uint64_t should_be_uint64_t;
 122 typedef uint64_t should_be_uint64_small_t;
 123 #else
 124 typedef unsigned long long should_be_uint64_t;
 125 typedef unsigned long should_be_uint64_small_t;
 126 #endif
 127
 128 class pkgVersioningSystem;
 129 class pkgCache                                                          /*{{{*/
 130 {
 131    public:
 132    // Cache element predeclarations
 133    struct Header;
 134    struct Group;
 135    struct Package;
 136    struct PackageFile;
 137    struct Version;
 138    struct Description;
 139    struct Provides;
 140    struct Dependency;
 141    struct StringItem;
 142    struct VerFile;
 143    struct DescFile;
 144
 145    // Iterators
 146    template<typename Str, typename Itr> class Iterator;
 147    class GrpIterator;
 148    class PkgIterator;
 149    class VerIterator;
 150    class DescIterator;
 151    class DepIterator;
 152    class PrvIterator;
 153    class PkgFileIterator;
 154    class VerFileIterator;
 155    class DescFileIterator;
 156
 157    class Namespace;
 158
 159    // These are all the constants used in the cache structures
 160
 161    // WARNING - if you change these lists you must also edit
 162    // the stringification in pkgcache.cc and also consider whether
 163    // the cache file will become incompatible.
 164    struct Dep
 165    {
 166       enum DepType {Depends=1,PreDepends=2,Suggests=3,Recommends=4,
 167          Conflicts=5,Replaces=6,Obsoletes=7,DpkgBreaks=8,Enhances=9};
 168       /** \brief available compare operators
 169
 170           The lower 4 bits are used to indicate what operator is being specified and
 171           the upper 4 bits are flags. OR indicates that the next package is
 172           or'd with the current package. */
 173       enum DepCompareOp {Or=0x10,NoOp=0,LessEq=0x1,GreaterEq=0x2,Less=0x3,
 174          Greater=0x4,Equals=0x5,NotEquals=0x6};
 175    };
 176
 177    struct State
 178    {
 179       /** \brief priority of a package version
 180
 181           Zero is used for unparsable or absent Priority fields. */
 182       enum VerPriority {Required=1,Important=2,Standard=3,Optional=4,Extra=5};
 183       enum PkgSelectedState {Unknown=0,Install=1,Hold=2,DeInstall=3,Purge=4};
 184       enum PkgInstState {Ok=0,ReInstReq=1,HoldInst=2,HoldReInstReq=3};
 185       enum PkgCurrentState {NotInstalled=0,UnPacked=1,HalfConfigured=2,
 186            HalfInstalled=4,ConfigFiles=5,Installed=6,
 187            TriggersAwaited=7,TriggersPending=8};
 188    };
 189
 190    struct Flag
 191    {
 192       enum PkgFlags {Auto=(1<<0),Essential=(1<<3),Important=(1<<4)};
 193       enum PkgFFlags {NotSource=(1<<0),NotAutomatic=(1<<1),ButAutomaticUpgrades=(1<<2)};
 194    };
 195
 196    protected:
 197
 198    // Memory mapped cache file
 199    std::string CacheFile;
 200    MMap &Map;
 201
 202    map_id_t sHash(const std::string &S) const APT_PURE;
 203    map_id_t sHash(const char *S) const APT_PURE;
 204
 205    public:
 206
 207    // Pointers to the arrays of items
 208    Header *HeaderP;
 209    Group *GrpP;
 210    Package *PkgP;
 211    VerFile *VerFileP;
 212    DescFile *DescFileP;
 213    PackageFile *PkgFileP;
 214    Version *VerP;
 215    Description *DescP;
 216    Provides *ProvideP;
 217    Dependency *DepP;
 218    APT_DEPRECATED StringItem *StringItemP;
 219    char *StrP;
 220
 221    virtual bool ReMap(bool const &Errorchecks = true);
 222    inline bool Sync() {return Map.Sync();}
 223    inline MMap &GetMap() {return Map;}
 224    inline void *DataEnd() {return ((unsigned char *)Map.Data()) + Map.Size();}
 225
 226    // String hashing function (512 range)
 227    inline map_id_t Hash(const std::string &S) const {return sHash(S);}
 228    inline map_id_t Hash(const char *S) const {return sHash(S);}
 229
 230    // Useful transformation things
 231    const char *Priority(unsigned char Priority);
 232
 233    // Accessors
 234    GrpIterator FindGrp(const std::string &Name);
 235    PkgIterator FindPkg(const std::string &Name);
 236    PkgIterator FindPkg(const std::string &Name, const std::string &Arch);
 237
 238    Header &Head() {return *HeaderP;}
 239    inline GrpIterator GrpBegin();
 240    inline GrpIterator GrpEnd();
 241    inline PkgIterator PkgBegin();
 242    inline PkgIterator PkgEnd();
 243    inline PkgFileIterator FileBegin();
 244    inline PkgFileIterator FileEnd();
 245
 246    inline bool MultiArchCache() const { return MultiArchEnabled; }
 247    inline char const * NativeArch();
 248
 249    // Make me a function
 250    pkgVersioningSystem *VS;
 251
 252    // Converters
 253    static const char *CompTypeDeb(unsigned char Comp) APT_CONST;
 254    static const char *CompType(unsigned char Comp) APT_CONST;
 255    static const char *DepType(unsigned char Dep);
 256
 257    pkgCache(MMap *Map,bool DoMap = true);
 258    virtual ~pkgCache() {}
 259
 260 private:
 261    bool MultiArchEnabled;
 262    APT_HIDDEN PkgIterator SingleArchFindPkg(const std::string &Name);
 263 };
 264                                                                         /*}}}*/
 265 // Header structure                                                     /*{{{*/
 266 struct pkgCache::Header
 267 {
 268    /** \brief Signature information
 269
 270        This must contain the hex value 0x98FE76DC which is designed to
 271        verify that the system loading the image has the same byte order
 272        and byte size as the system saving the image */
 273    unsigned long Signature;
 274    /** These contain the version of the cache file */
 275    short MajorVersion;
 276    short MinorVersion;
 277    /** \brief indicates if the cache should be erased
 278
 279        Dirty is true if the cache file was opened for reading, the client
 280        expects to have written things to it and have not fully synced it.
 281        The file should be erased and rebuilt if it is true. */
 282    bool Dirty;
 283
 284    /** \brief Size of structure values
 285
 286        All *Sz variables contains the sizeof() that particular structure.
 287        It is used as an extra consistency check on the structure of the file.
 288
 289        If any of the size values do not exactly match what the client expects
 290        then the client should refuse the load the file. */
 291    unsigned short HeaderSz;
 292    unsigned short GroupSz;
 293    unsigned short PackageSz;
 294    unsigned short PackageFileSz;
 295    unsigned short VersionSz;
 296    unsigned short DescriptionSz;
 297    unsigned short DependencySz;
 298    unsigned short ProvidesSz;
 299    unsigned short VerFileSz;
 300    unsigned short DescFileSz;
 301
 302    /** \brief Structure counts
 303
 304        These indicate the number of each structure contained in the cache.
 305        PackageCount is especially useful for generating user state structures.
 306        See Package::Id for more info. */
 307    map_id_t GroupCount;
 308    map_id_t PackageCount;
 309    map_id_t VersionCount;
 310    map_id_t DescriptionCount;
 311    map_id_t DependsCount;
 312    map_fileid_t PackageFileCount;
 313    map_fileid_t VerFileCount;
 314    map_fileid_t DescFileCount;
 315    map_id_t ProvidesCount;
 316
 317    /** \brief index of the first PackageFile structure
 318
 319        The PackageFile structures are singly linked lists that represent
 320        all package files that have been merged into the cache. */
 321    map_pointer_t FileList;
 322 #if APT_PKG_ABI < 413
 323    APT_DEPRECATED map_pointer_t StringList;
 324 #endif
 325    /** \brief String representing the version system used */
 326    map_pointer_t VerSysName;
 327    /** \brief native architecture the cache was built against */
 328    map_pointer_t Architecture;
 329 #if APT_PKG_ABI >= 413
 330    /** \brief all architectures the cache was built against */
 331    map_pointer_t Architectures;
 332 #endif
 333    /** \brief The maximum size of a raw entry from the original Package file */
 334    map_filesize_t MaxVerFileSize;
 335    /** \brief The maximum size of a raw entry from the original Translation file */
 336    map_filesize_t MaxDescFileSize;
 337
 338    /** \brief The Pool structures manage the allocation pools that the generator uses
 339
 340        Start indicates the first byte of the pool, Count is the number of objects
 341        remaining in the pool and ItemSize is the structure size (alignment factor)
 342        of the pool. An ItemSize of 0 indicates the pool is empty. There should be
 343        the same number of pools as there are structure types. The generator
 344        stores this information so future additions can make use of any unused pool
 345        blocks. */
 346    DynamicMMap::Pool Pools[9];
 347
 348    /** \brief hash tables providing rapid group/package name lookup
 349
 350        Each group/package name is inserted into a hash table using pkgCache::Hash(const &string)
 351        By iterating over each entry in the hash table it is possible to iterate over
 352        the entire list of packages. Hash Collisions are handled with a singly linked
 353        list of packages based at the hash item. The linked list contains only
 354        packages that match the hashing function.
 355        In the PkgHashTable is it possible that multiple packages have the same name -
 356        these packages are stored as a sequence in the list.
 357        The size of both tables is the same. */
 358 #if APT_PKG_ABI >= 413
 359    unsigned int HashTableSize;
 360    unsigned int GetHashTableSize() const { return HashTableSize; }
 361    void SetHashTableSize(unsigned int const sz) { HashTableSize = sz; }
 362    map_pointer_t GetArchitectures() const { return Architectures; }
 363    void SetArchitectures(map_pointer_t const idx) { Architectures = idx; }
 364 #else
 365    // BEWARE: these tables are pretty much empty and just here for abi compat
 366    map_ptrloc PkgHashTable[2*1048];
 367    map_ptrloc GrpHashTable[2*1048];
 368    unsigned int GetHashTableSize() const { return PkgHashTable[0]; }
 369    void SetHashTableSize(unsigned int const sz) { PkgHashTable[0] = sz; }
 370    map_pointer_t GetArchitectures() const { return PkgHashTable[1]; }
 371    void SetArchitectures(map_pointer_t const idx) { PkgHashTable[1] = idx; }
 372 #endif
 373    map_pointer_t * PkgHashTableP() const { return (map_pointer_t*) (this + 1); }
 374    map_pointer_t * GrpHashTableP() const { return PkgHashTableP() + GetHashTableSize(); }
 375
 376    /** \brief Size of the complete cache file */
 377    should_be_uint64_small_t CacheFileSize;
 378
 379    bool CheckSizes(Header &Against) const APT_PURE;
 380    Header();
 381 };
 382                                                                         /*}}}*/
 383 // Group structure                                                      /*{{{*/
 384 /** \brief groups architecture depending packages together
 385
 386     On or more packages with the same name form a group, so we have
 387     a simple way to access a package built for different architectures
 388     Group exists in a singly linked list of group records starting at
 389     the hash index of the name in the pkgCache::Header::GrpHashTable */
 390 struct pkgCache::Group
 391 {
 392    /** \brief Name of the group */
 393    map_stringitem_t Name;
 394
 395    // Linked List
 396    /** \brief Link to the first package which belongs to the group */
 397    map_pointer_t FirstPackage;  // Package
 398    /** \brief Link to the last package which belongs to the group */
 399    map_pointer_t LastPackage;   // Package
 400    /** \brief Link to the next Group */
 401    map_pointer_t Next;          // Group
 402    /** \brief unique sequel ID */
 403    should_be_map_id_t ID;
 404
 405 };
 406                                                                         /*}}}*/
 407 // Package structure                                                    /*{{{*/
 408 /** \brief contains information for a single unique package
 409
 410     There can be any number of versions of a given package.
 411     Package exists in a singly linked list of package records starting at
 412     the hash index of the name in the pkgCache::Header::PkgHashTable
 413
 414     A package can be created for every architecture so package names are
 415     not unique, but it is guaranteed that packages with the same name
 416     are sequencel ordered in the list. Packages with the same name can be
 417     accessed with the Group.
 418 */
 419 struct pkgCache::Package
 420 {
 421    /** \brief Name of the package
 422     * Note that the access method Name() will remain. It is just this data member
 423     * deprecated as this information is already stored and available via the
 424     * associated Group – so it is wasting precious binary cache space */
 425    APT_DEPRECATED map_stringitem_t Name;
 426    /** \brief Architecture of the package */
 427    map_stringitem_t Arch;
 428    /** \brief Base of a singly linked list of versions
 429
 430        Each structure represents a unique version of the package.
 431        The version structures contain links into PackageFile and the
 432        original text file as well as detailed information about the size
 433        and dependencies of the specific package. In this way multiple
 434        versions of a package can be cleanly handled by the system.
 435        Furthermore, this linked list is guaranteed to be sorted
 436        from Highest version to lowest version with no duplicate entries. */
 437    map_pointer_t VersionList;       // Version
 438    /** \brief index to the installed version */
 439    map_pointer_t CurrentVer;        // Version
 440    /** \brief indicates nothing (consistently)
 441        This field used to contain ONE section the package belongs to,
 442        if those differs between versions it is a RANDOM one.
 443        The Section() method tries to reproduce it, but the only sane
 444        thing to do is use the Section field from the version! */
 445    APT_DEPRECATED map_ptrloc Section; // StringItem
 446    /** \brief index of the group this package belongs to */
 447    map_pointer_t Group;             // Group the Package belongs to
 448
 449    // Linked list
 450    /** \brief Link to the next package in the same bucket */
 451    map_pointer_t NextPackage;       // Package
 452    /** \brief List of all dependencies on this package */
 453    map_pointer_t RevDepends;        // Dependency
 454    /** \brief List of all "packages" this package provide */
 455    map_pointer_t ProvidesList;      // Provides
 456
 457    // Install/Remove/Purge etc
 458    /** \brief state that the user wishes the package to be in */
 459    unsigned char SelectedState;     // What
 460    /** \brief installation state of the package
 461
 462        This should be "ok" but in case the installation failed
 463        it will be different.
 464    */
 465    unsigned char InstState;         // Flags
 466    /** \brief indicates if the package is installed */
 467    unsigned char CurrentState;      // State
 468
 469    /** \brief unique sequel ID
 470
 471        ID is a unique value from 0 to Header->PackageCount assigned by the generator.
 472        This allows clients to create an array of size PackageCount and use it to store
 473        state information for the package map. For instance the status file emitter uses
 474        this to track which packages have been emitted already. */
 475    should_be_map_id_t ID;
 476    /** \brief some useful indicators of the package's state */
 477    unsigned long Flags;
 478 };
 479                                                                         /*}}}*/
 480 // Package File structure                                               /*{{{*/
 481 /** \brief stores information about the files used to generate the cache
 482
 483     Package files are referenced by Version structures to be able to know
 484     after the generation still from which Packages file includes this Version
 485     as we need this information later on e.g. for pinning. */
 486 struct pkgCache::PackageFile
 487 {
 488    /** \brief physical disk file that this PackageFile represents */
 489    map_stringitem_t FileName;
 490    /** \brief the release information
 491
 492        Please see the files document for a description of what the
 493        release information means. */
 494    map_stringitem_t Archive;
 495    map_stringitem_t Codename;
 496    map_stringitem_t Component;
 497    map_stringitem_t Version;
 498    map_stringitem_t Origin;
 499    map_stringitem_t Label;
 500    map_stringitem_t Architecture;
 501    /** \brief The site the index file was fetched from */
 502    map_stringitem_t Site;
 503    /** \brief indicates what sort of index file this is
 504
 505        @TODO enumerate at least the possible indexes */
 506    map_stringitem_t IndexType;
 507    /** \brief Size of the file
 508
 509        Used together with the modification time as a
 510        simple check to ensure that the Packages
 511        file has not been altered since Cache generation. */
 512    map_filesize_t Size;
 513    /** \brief Modification time for the file */
 514    time_t mtime;
 515
 516    /** @TODO document PackageFile::Flags */
 517    unsigned long Flags;
 518
 519    // Linked list
 520    /** \brief Link to the next PackageFile in the Cache */
 521    map_pointer_t NextFile;        // PackageFile
 522    /** \brief unique sequel ID */
 523    should_be_map_fileid_t ID;
 524 };
 525                                                                         /*}}}*/
 526 // VerFile structure                                                    /*{{{*/
 527 /** \brief associates a version with a PackageFile
 528
 529     This allows a full description of all Versions in all files
 530     (and hence all sources) under consideration. */
 531 struct pkgCache::VerFile
 532 {
 533    /** \brief index of the package file that this version was found in */
 534    map_pointer_t File;           // PackageFile
 535    /** \brief next step in the linked list */
 536    map_pointer_t NextFile;       // PkgVerFile
 537    /** \brief position in the package file */
 538    should_be_map_filesize_t Offset;         // File offset
 539    /** @TODO document pkgCache::VerFile::Size */
 540    map_filesize_t Size;
 541 };
 542                                                                         /*}}}*/
 543 // DescFile structure                                                   /*{{{*/
 544 /** \brief associates a description with a Translation file */
 545 struct pkgCache::DescFile
 546 {
 547    /** \brief index of the file that this description was found in */
 548    map_pointer_t File;           // PackageFile
 549    /** \brief next step in the linked list */
 550    map_pointer_t NextFile;       // PkgVerFile
 551    /** \brief position in the file */
 552    should_be_map_filesize_t Offset;         // File offset
 553    /** @TODO document pkgCache::DescFile::Size */
 554    map_filesize_t Size;
 555 };
 556                                                                         /*}}}*/
 557 // Version structure                                                    /*{{{*/
 558 /** \brief information for a single version of a package
 559
 560     The version list is always sorted from highest version to lowest
 561     version by the generator. Equal version numbers are either merged
 562     or handled as separate versions based on the Hash value. */
 563 struct pkgCache::Version
 564 {
 565    /** \brief complete version string */
 566    map_stringitem_t VerStr;
 567    /** \brief section this version is filled in */
 568    map_stringitem_t Section;
 569 #if APT_PKG_ABI >= 413
 570    /** \brief source package name this version comes from
 571       Always contains the name, even if it is the same as the binary name */
 572    map_stringitem_t SourcePkgName;
 573    /** \brief source version this version comes from
 574       Always contains the version string, even if it is the same as the binary version */
 575    map_stringitem_t SourceVerStr;
 576 #endif
 577
 578    /** \brief Multi-Arch capabilities of a package version */
 579    enum VerMultiArch { None = 0, /*!< is the default and doesn't trigger special behaviour */
 580                        All = (1<<0), /*!< will cause that Ver.Arch() will report "all" */
 581                        Foreign = (1<<1), /*!< can satisfy dependencies in another architecture */
 582                        Same = (1<<2), /*!< can be co-installed with itself from other architectures */
 583                        Allowed = (1<<3), /*!< other packages are allowed to depend on thispkg:any */
 584                        AllForeign = All | Foreign,
 585                        AllAllowed = All | Allowed };
 586    /** \brief stores the MultiArch capabilities of this version
 587
 588        Flags used are defined in pkgCache::Version::VerMultiArch
 589    */
 590    unsigned char MultiArch;
 591
 592    /** \brief references all the PackageFile's that this version came from
 593
 594        FileList can be used to determine what distribution(s) the Version
 595        applies to. If FileList is 0 then this is a blank version.
 596        The structure should also have a 0 in all other fields excluding
 597        pkgCache::Version::VerStr and Possibly pkgCache::Version::NextVer. */
 598    map_pointer_t FileList;          // VerFile
 599    /** \brief next (lower or equal) version in the linked list */
 600    map_pointer_t NextVer;           // Version
 601    /** \brief next description in the linked list */
 602    map_pointer_t DescriptionList;   // Description
 603    /** \brief base of the dependency list */
 604    map_pointer_t DependsList;       // Dependency
 605    /** \brief links to the owning package
 606
 607        This allows reverse dependencies to determine the package */
 608    map_pointer_t ParentPkg;         // Package
 609    /** \brief list of pkgCache::Provides */
 610    map_pointer_t ProvidesList;      // Provides
 611
 612    /** \brief archive size for this version
 613
 614        For Debian this is the size of the .deb file. */
 615    should_be_uint64_t Size; // These are the .deb size
 616    /** \brief uncompressed size for this version */
 617    should_be_uint64_t InstalledSize;
 618    /** \brief characteristic value representing this version
 619
 620        No two packages in existence should have the same VerStr
 621        and Hash with different contents. */
 622    unsigned short Hash;
 623    /** \brief unique sequel ID */
 624    should_be_map_id_t ID;
 625    /** \brief parsed priority value */
 626    unsigned char Priority;
 627 };
 628                                                                         /*}}}*/
 629 // Description structure                                                /*{{{*/
 630 /** \brief datamember of a linked list of available description for a version */
 631 struct pkgCache::Description
 632 {
 633    /** \brief Language code of this description (translation)
 634
 635        If the value has a 0 length then this is read using the Package
 636        file else the Translation-CODE file is used. */
 637    map_stringitem_t language_code;
 638    /** \brief MD5sum of the original description
 639
 640        Used to map Translations of a description to a version
 641        and to check that the Translation is up-to-date. */
 642    map_stringitem_t md5sum;
 643
 644    /** @TODO document pkgCache::Description::FileList */
 645    map_pointer_t FileList;          // DescFile
 646    /** \brief next translation for this description */
 647    map_pointer_t NextDesc;          // Description
 648    /** \brief the text is a description of this package */
 649    map_pointer_t ParentPkg;         // Package
 650
 651    /** \brief unique sequel ID */
 652    should_be_map_id_t ID;
 653 };
 654                                                                         /*}}}*/
 655 // Dependency structure                                                 /*{{{*/
 656 /** \brief information for a single dependency record
 657
 658     The records are split up like this to ease processing by the client.
 659     The base of the linked list is pkgCache::Version::DependsList.
 660     All forms of dependencies are recorded here including Depends,
 661     Recommends, Suggests, Enhances, Conflicts, Replaces and Breaks. */
 662 struct pkgCache::Dependency
 663 {
 664    /** \brief string of the version the dependency is applied against */
 665    map_stringitem_t Version;
 666    /** \brief index of the package this depends applies to
 667
 668        The generator will - if the package does not already exist -
 669        create a blank (no version records) package. */
 670    map_pointer_t Package;         // Package
 671    /** \brief next dependency of this version */
 672    map_pointer_t NextDepends;     // Dependency
 673    /** \brief next reverse dependency of this package */
 674    map_pointer_t NextRevDepends;  // Dependency
 675    /** \brief version of the package which has the reverse depends */
 676    map_pointer_t ParentVer;       // Version
 677
 678    /** \brief unique sequel ID */
 679    should_be_map_id_t ID;
 680    /** \brief Dependency type - Depends, Recommends, Conflicts, etc */
 681    unsigned char Type;
 682    /** \brief comparison operator specified on the depends line
 683
 684        If the high bit is set then it is a logical OR with the previous record. */
 685    unsigned char CompareOp;
 686 };
 687                                                                         /*}}}*/
 688 // Provides structure                                                   /*{{{*/
 689 /** \brief handles virtual packages
 690
 691     When a Provides: line is encountered a new provides record is added
 692     associating the package with a virtual package name.
 693     The provides structures are linked off the package structures.
 694     This simplifies the analysis of dependencies and other aspects A provides
 695     refers to a specific version of a specific package, not all versions need to
 696     provide that provides.*/
 697 struct pkgCache::Provides
 698 {
 699    /** \brief index of the package providing this */
 700    map_pointer_t ParentPkg;        // Package
 701    /** \brief index of the version this provide line applies to */
 702    map_pointer_t Version;          // Version
 703    /** \brief version in the provides line (if any)
 704
 705        This version allows dependencies to depend on specific versions of a
 706        Provides, as well as allowing Provides to override existing packages.
 707        This is experimental. Note that Debian doesn't allow versioned provides */
 708    map_stringitem_t ProvideVersion;
 709    /** \brief next provides (based of package) */
 710    map_pointer_t NextProvides;     // Provides
 711    /** \brief next provides (based of version) */
 712    map_pointer_t NextPkgProv;      // Provides
 713 };
 714                                                                         /*}}}*/
 715 // UNUSED StringItem structure                                          /*{{{*/
 716 struct APT_DEPRECATED  pkgCache::StringItem
 717 {
 718    /** \brief string this refers to */
 719    map_ptrloc String;        // StringItem
 720    /** \brief Next link in the chain */
 721    map_ptrloc NextItem;      // StringItem
 722 };
 723                                                                         /*}}}*/
 724
 725 inline char const * pkgCache::NativeArch()
 726         { return StrP + HeaderP->Architecture; }
 727
 728 #include <apt-pkg/cacheiterators.h>
 729
 730 inline pkgCache::GrpIterator pkgCache::GrpBegin()
 731        {return GrpIterator(*this);}
 732 inline pkgCache::GrpIterator pkgCache::GrpEnd()
 733        {return GrpIterator(*this,GrpP);}
 734 inline pkgCache::PkgIterator pkgCache::PkgBegin()
 735        {return PkgIterator(*this);}
 736 inline pkgCache::PkgIterator pkgCache::PkgEnd()
 737        {return PkgIterator(*this,PkgP);}
 738 inline pkgCache::PkgFileIterator pkgCache::FileBegin()
 739        {return PkgFileIterator(*this,PkgFileP + HeaderP->FileList);}
 740 inline pkgCache::PkgFileIterator pkgCache::FileEnd()
 741        {return PkgFileIterator(*this,PkgFileP);}
 742
 743 // Oh I wish for Real Name Space Support
 744 class pkgCache::Namespace                                               /*{{{*/
 745 {
 746    public:
 747    typedef pkgCache::GrpIterator GrpIterator;
 748    typedef pkgCache::PkgIterator PkgIterator;
 749    typedef pkgCache::VerIterator VerIterator;
 750    typedef pkgCache::DescIterator DescIterator;
 751    typedef pkgCache::DepIterator DepIterator;
 752    typedef pkgCache::PrvIterator PrvIterator;
 753    typedef pkgCache::PkgFileIterator PkgFileIterator;
 754    typedef pkgCache::VerFileIterator VerFileIterator;
 755    typedef pkgCache::Version Version;
 756    typedef pkgCache::Description Description;
 757    typedef pkgCache::Package Package;
 758    typedef pkgCache::Header Header;
 759    typedef pkgCache::Dep Dep;
 760    typedef pkgCache::Flag Flag;
 761 };
 762                                                                         /*}}}*/
 763 #endif