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
  78 #include <string>
  79 #include <time.h>
  80 #include <apt-pkg/mmap.h>
  81
  82 using std::string;
  83
  84 class pkgVersioningSystem;
  85 class pkgCache                                                          /*{{{*/
  86 {
  87    public:
  88    // Cache element predeclarations
  89    struct Header;
  90    struct Group;
  91    struct Package;
  92    struct PackageFile;
  93    struct Version;
  94    struct Description;
  95    struct Provides;
  96    struct Dependency;
  97    struct StringItem;
  98    struct VerFile;
  99    struct DescFile;
 100
 101    // Iterators
 102    template<typename Str, typename Itr> class Iterator;
 103    class GrpIterator;
 104    class PkgIterator;
 105    class VerIterator;
 106    class DescIterator;
 107    class DepIterator;
 108    class PrvIterator;
 109    class PkgFileIterator;
 110    class VerFileIterator;
 111    class DescFileIterator;
 112
 113    class Namespace;
 114
 115    // These are all the constants used in the cache structures
 116
 117    // WARNING - if you change these lists you must also edit
 118    // the stringification in pkgcache.cc and also consider whether
 119    // the cache file will become incompatible.
 120    struct Dep
 121    {
 122       enum DepType {Depends=1,PreDepends=2,Suggests=3,Recommends=4,
 123          Conflicts=5,Replaces=6,Obsoletes=7,DpkgBreaks=8,Enhances=9};
 124       /** \brief available compare operators
 125
 126           The lower 4 bits are used to indicate what operator is being specified and
 127           the upper 4 bits are flags. OR indicates that the next package is
 128           or'd with the current package. */
 129       enum DepCompareOp {Or=0x10,NoOp=0,LessEq=0x1,GreaterEq=0x2,Less=0x3,
 130          Greater=0x4,Equals=0x5,NotEquals=0x6};
 131    };
 132
 133    struct State
 134    {
 135       /** \brief priority of a package version
 136
 137           Zero is used for unparsable or absent Priority fields. */
 138       enum VerPriority {Important=1,Required=2,Standard=3,Optional=4,Extra=5};
 139       enum PkgSelectedState {Unknown=0,Install=1,Hold=2,DeInstall=3,Purge=4};
 140       enum PkgInstState {Ok=0,ReInstReq=1,HoldInst=2,HoldReInstReq=3};
 141       enum PkgCurrentState {NotInstalled=0,UnPacked=1,HalfConfigured=2,
 142            HalfInstalled=4,ConfigFiles=5,Installed=6,
 143            TriggersAwaited=7,TriggersPending=8};
 144    };
 145
 146    struct Flag
 147    {
 148       enum PkgFlags {Auto=(1<<0),Essential=(1<<3),Important=(1<<4)};
 149       enum PkgFFlags {NotSource=(1<<0),NotAutomatic=(1<<1),ButAutomaticUpgrades=(1<<2)};
 150    };
 151
 152    protected:
 153
 154    // Memory mapped cache file
 155    string CacheFile;
 156    MMap &Map;
 157
 158    unsigned long sHash(const string &S) const;
 159    unsigned long sHash(const char *S) const;
 160
 161    public:
 162
 163    // Pointers to the arrays of items
 164    Header *HeaderP;
 165    Group *GrpP;
 166    Package *PkgP;
 167    VerFile *VerFileP;
 168    DescFile *DescFileP;
 169    PackageFile *PkgFileP;
 170    Version *VerP;
 171    Description *DescP;
 172    Provides *ProvideP;
 173    Dependency *DepP;
 174    StringItem *StringItemP;
 175    char *StrP;
 176
 177    virtual bool ReMap(bool const &Errorchecks = true);
 178    inline bool Sync() {return Map.Sync();};
 179    inline MMap &GetMap() {return Map;};
 180    inline void *DataEnd() {return ((unsigned char *)Map.Data()) + Map.Size();};
 181
 182    // String hashing function (512 range)
 183    inline unsigned long Hash(const string &S) const {return sHash(S);};
 184    inline unsigned long Hash(const char *S) const {return sHash(S);};
 185
 186    // Useful transformation things
 187    const char *Priority(unsigned char Priority);
 188
 189    // Accessors
 190    GrpIterator FindGrp(const string &Name);
 191    PkgIterator FindPkg(const string &Name);
 192    PkgIterator FindPkg(const string &Name, const string &Arch);
 193
 194    Header &Head() {return *HeaderP;};
 195    inline GrpIterator GrpBegin();
 196    inline GrpIterator GrpEnd();
 197    inline PkgIterator PkgBegin();
 198    inline PkgIterator PkgEnd();
 199    inline PkgFileIterator FileBegin();
 200    inline PkgFileIterator FileEnd();
 201
 202    inline bool MultiArchCache() const { return MultiArchEnabled; };
 203
 204    // Make me a function
 205    pkgVersioningSystem *VS;
 206
 207    // Converters
 208    static const char *CompTypeDeb(unsigned char Comp);
 209    static const char *CompType(unsigned char Comp);
 210    static const char *DepType(unsigned char Dep);
 211
 212    pkgCache(MMap *Map,bool DoMap = true);
 213    virtual ~pkgCache() {};
 214
 215 private:
 216    bool MultiArchEnabled;
 217    PkgIterator SingleArchFindPkg(const string &Name);
 218    inline char const * const NativeArch() const;
 219 };
 220                                                                         /*}}}*/
 221 // Header structure                                                     /*{{{*/
 222 struct pkgCache::Header
 223 {
 224    /** \brief Signature information
 225
 226        This must contain the hex value 0x98FE76DC which is designed to
 227        verify that the system loading the image has the same byte order
 228        and byte size as the system saving the image */
 229    unsigned long Signature;
 230    /** These contain the version of the cache file */
 231    short MajorVersion;
 232    short MinorVersion;
 233    /** \brief indicates if the cache should be erased
 234
 235        Dirty is true if the cache file was opened for reading, the client
 236        expects to have written things to it and have not fully synced it.
 237        The file should be erased and rebuilt if it is true. */
 238    bool Dirty;
 239
 240    /** \brief Size of structure values
 241
 242        All *Sz variables contains the sizeof() that particular structure.
 243        It is used as an extra consistency check on the structure of the file.
 244
 245        If any of the size values do not exactly match what the client expects
 246        then the client should refuse the load the file. */
 247    unsigned short HeaderSz;
 248    unsigned short GroupSz;
 249    unsigned short PackageSz;
 250    unsigned short PackageFileSz;
 251    unsigned short VersionSz;
 252    unsigned short DescriptionSz;
 253    unsigned short DependencySz;
 254    unsigned short ProvidesSz;
 255    unsigned short VerFileSz;
 256    unsigned short DescFileSz;
 257
 258    /** \brief Structure counts
 259
 260        These indicate the number of each structure contained in the cache.
 261        PackageCount is especially useful for generating user state structures.
 262        See Package::Id for more info. */
 263    unsigned long GroupCount;
 264    unsigned long PackageCount;
 265    unsigned long VersionCount;
 266    unsigned long DescriptionCount;
 267    unsigned long DependsCount;
 268    unsigned long PackageFileCount;
 269    unsigned long VerFileCount;
 270    unsigned long DescFileCount;
 271    unsigned long ProvidesCount;
 272
 273    /** \brief index of the first PackageFile structure
 274
 275        The PackageFile structures are singly linked lists that represent
 276        all package files that have been merged into the cache. */
 277    map_ptrloc FileList;
 278    /** \brief index of the first StringItem structure
 279
 280        The cache contains a list of all the unique strings (StringItems).
 281        The parser reads this list into memory so it can match strings
 282        against it.*/
 283    map_ptrloc StringList;
 284    /** \brief String representing the version system used */
 285    map_ptrloc VerSysName;
 286    /** \brief Architecture(s) the cache was built against */
 287    map_ptrloc Architecture;
 288    /** \brief The maximum size of a raw entry from the original Package file */
 289    unsigned long MaxVerFileSize;
 290    /** \brief The maximum size of a raw entry from the original Translation file */
 291    unsigned long MaxDescFileSize;
 292
 293    /** \brief The Pool structures manage the allocation pools that the generator uses
 294
 295        Start indicates the first byte of the pool, Count is the number of objects
 296        remaining in the pool and ItemSize is the structure size (alignment factor)
 297        of the pool. An ItemSize of 0 indicates the pool is empty. There should be
 298        the same number of pools as there are structure types. The generator
 299        stores this information so future additions can make use of any unused pool
 300        blocks. */
 301    DynamicMMap::Pool Pools[9];
 302
 303    /** \brief hash tables providing rapid group/package name lookup
 304
 305        Each group/package name is inserted into the hash table using pkgCache::Hash(const &string)
 306        By iterating over each entry in the hash table it is possible to iterate over
 307        the entire list of packages. Hash Collisions are handled with a singly linked
 308        list of packages based at the hash item. The linked list contains only
 309        packages that match the hashing function.
 310        In the PkgHashTable is it possible that multiple packages have the same name -
 311        these packages are stored as a sequence in the list.
 312
 313        Beware: The Hashmethod assumes that the hash table sizes are equal */
 314    map_ptrloc PkgHashTable[2*1048];
 315    map_ptrloc GrpHashTable[2*1048];
 316
 317    bool CheckSizes(Header &Against) const;
 318    Header();
 319 };
 320                                                                         /*}}}*/
 321 // Group structure                                                      /*{{{*/
 322 /** \brief groups architecture depending packages together
 323
 324     On or more packages with the same name form a group, so we have
 325     a simple way to access a package built for different architectures
 326     Group exists in a singly linked list of group records starting at
 327     the hash index of the name in the pkgCache::Header::GrpHashTable */
 328 struct pkgCache::Group
 329 {
 330    /** \brief Name of the group */
 331    map_ptrloc Name;             // StringItem
 332
 333    // Linked List
 334    /** \brief Link to the first package which belongs to the group */
 335    map_ptrloc FirstPackage;     // Package
 336    /** \brief Link to the last package which belongs to the group */
 337    map_ptrloc LastPackage;      // Package
 338    /** \brief Link to the next Group */
 339    map_ptrloc Next;             // Group
 340    /** \brief unique sequel ID */
 341    unsigned int ID;
 342
 343 };
 344                                                                         /*}}}*/
 345 // Package structure                                                    /*{{{*/
 346 /** \brief contains information for a single unique package
 347
 348     There can be any number of versions of a given package.
 349     Package exists in a singly linked list of package records starting at
 350     the hash index of the name in the pkgCache::Header::PkgHashTable
 351
 352     A package can be created for every architecture so package names are
 353     not unique, but it is garanteed that packages with the same name
 354     are sequencel ordered in the list. Packages with the same name can be
 355     accessed with the Group.
 356 */
 357 struct pkgCache::Package
 358 {
 359    /** \brief Name of the package */
 360    map_ptrloc Name;              // StringItem
 361    /** \brief Architecture of the package */
 362    map_ptrloc Arch;              // StringItem
 363    /** \brief Base of a singly linked list of versions
 364
 365        Each structure represents a unique version of the package.
 366        The version structures contain links into PackageFile and the
 367        original text file as well as detailed information about the size
 368        and dependencies of the specific package. In this way multiple
 369        versions of a package can be cleanly handled by the system.
 370        Furthermore, this linked list is guaranteed to be sorted
 371        from Highest version to lowest version with no duplicate entries. */
 372    map_ptrloc VersionList;       // Version
 373    /** \brief index to the installed version */
 374    map_ptrloc CurrentVer;        // Version
 375    /** \brief indicates the deduced section
 376
 377        Should be the index to the string "Unknown" or to the section
 378        of the last parsed item. */
 379    map_ptrloc Section;           // StringItem
 380    /** \brief index of the group this package belongs to */
 381    map_ptrloc Group;             // Group the Package belongs to
 382
 383    // Linked list
 384    /** \brief Link to the next package in the same bucket */
 385    map_ptrloc NextPackage;       // Package
 386    /** \brief List of all dependencies on this package */
 387    map_ptrloc RevDepends;        // Dependency
 388    /** \brief List of all "packages" this package provide */
 389    map_ptrloc ProvidesList;      // Provides
 390
 391    // Install/Remove/Purge etc
 392    /** \brief state that the user wishes the package to be in */
 393    unsigned char SelectedState;     // What
 394    /** \brief installation state of the package
 395
 396        This should be "ok" but in case the installation failed
 397        it will be different.
 398    */
 399    unsigned char InstState;         // Flags
 400    /** \brief indicates if the package is installed */
 401    unsigned char CurrentState;      // State
 402
 403    /** \brief unique sequel ID
 404
 405        ID is a unique value from 0 to Header->PackageCount assigned by the generator.
 406        This allows clients to create an array of size PackageCount and use it to store
 407        state information for the package map. For instance the status file emitter uses
 408        this to track which packages have been emitted already. */
 409    unsigned int ID;
 410    /** \brief some useful indicators of the package's state */
 411    unsigned long Flags;
 412 };
 413                                                                         /*}}}*/
 414 // Package File structure                                               /*{{{*/
 415 /** \brief stores information about the files used to generate the cache
 416
 417     Package files are referenced by Version structures to be able to know
 418     after the generation still from which Packages file includes this Version
 419     as we need this information later on e.g. for pinning. */
 420 struct pkgCache::PackageFile
 421 {
 422    /** \brief physical disk file that this PackageFile represents */
 423    map_ptrloc FileName;        // StringItem
 424    /** \brief the release information
 425
 426        Please see the files document for a description of what the
 427        release information means. */
 428    map_ptrloc Archive;         // StringItem
 429    map_ptrloc Codename;        // StringItem
 430    map_ptrloc Component;       // StringItem
 431    map_ptrloc Version;         // StringItem
 432    map_ptrloc Origin;          // StringItem
 433    map_ptrloc Label;           // StringItem
 434    map_ptrloc Architecture;    // StringItem
 435    /** \brief The site the index file was fetched from */
 436    map_ptrloc Site;            // StringItem
 437    /** \brief indicates what sort of index file this is
 438
 439        @TODO enumerate at least the possible indexes */
 440    map_ptrloc IndexType;       // StringItem
 441    /** \brief Size of the file
 442
 443        Used together with the modification time as a
 444        simple check to ensure that the Packages
 445        file has not been altered since Cache generation. */
 446    unsigned long Size;
 447    /** \brief Modification time for the file */
 448    time_t mtime;
 449
 450    /* @TODO document PackageFile::Flags */
 451    unsigned long Flags;
 452
 453    // Linked list
 454    /** \brief Link to the next PackageFile in the Cache */
 455    map_ptrloc NextFile;        // PackageFile
 456    /** \brief unique sequel ID */
 457    unsigned int ID;
 458 };
 459                                                                         /*}}}*/
 460 // VerFile structure                                                    /*{{{*/
 461 /** \brief associates a version with a PackageFile
 462
 463     This allows a full description of all Versions in all files
 464     (and hence all sources) under consideration. */
 465 struct pkgCache::VerFile
 466 {
 467    /** \brief index of the package file that this version was found in */
 468    map_ptrloc File;           // PackageFile
 469    /** \brief next step in the linked list */
 470    map_ptrloc NextFile;       // PkgVerFile
 471    /** \brief position in the package file */
 472    map_ptrloc Offset;         // File offset
 473    /* @TODO document pkgCache::VerFile::Size */
 474    unsigned long Size;
 475 };
 476                                                                         /*}}}*/
 477 // DescFile structure                                                   /*{{{*/
 478 /** \brief associates a description with a Translation file */
 479 struct pkgCache::DescFile
 480 {
 481    /** \brief index of the file that this description was found in */
 482    map_ptrloc File;           // PackageFile
 483    /** \brief next step in the linked list */
 484    map_ptrloc NextFile;       // PkgVerFile
 485    /** \brief position in the file */
 486    map_ptrloc Offset;         // File offset
 487    /* @TODO document pkgCache::DescFile::Size */
 488    unsigned long Size;
 489 };
 490                                                                         /*}}}*/
 491 // Version structure                                                    /*{{{*/
 492 /** \brief information for a single version of a package
 493
 494     The version list is always sorted from highest version to lowest
 495     version by the generator. Equal version numbers are either merged
 496     or handled as separate versions based on the Hash value. */
 497 struct pkgCache::Version
 498 {
 499    /** \brief complete version string */
 500    map_ptrloc VerStr;            // StringItem
 501    /** \brief section this version is filled in */
 502    map_ptrloc Section;           // StringItem
 503    /** \brief stores the MultiArch capabilities of this version
 504
 505        None is the default and doesn't trigger special behaviour,
 506        Foreign means that this version can fulfill dependencies even
 507        if it is built for another architecture as the requester.
 508        Same indicates that builds for different architectures can
 509        be co-installed on the system */
 510    /* FIXME: A bitflag would be better with the next abibreak… */
 511    enum {None, All, Foreign, Same, Allowed, AllForeign, AllAllowed} MultiArch;
 512
 513    /** \brief references all the PackageFile's that this version came from
 514
 515        FileList can be used to determine what distribution(s) the Version
 516        applies to. If FileList is 0 then this is a blank version.
 517        The structure should also have a 0 in all other fields excluding
 518        pkgCache::Version::VerStr and Possibly pkgCache::Version::NextVer. */
 519    map_ptrloc FileList;          // VerFile
 520    /** \brief next (lower or equal) version in the linked list */
 521    map_ptrloc NextVer;           // Version
 522    /** \brief next description in the linked list */
 523    map_ptrloc DescriptionList;   // Description
 524    /** \brief base of the dependency list */
 525    map_ptrloc DependsList;       // Dependency
 526    /** \brief links to the owning package
 527
 528        This allows reverse dependencies to determine the package */
 529    map_ptrloc ParentPkg;         // Package
 530    /** \brief list of pkgCache::Provides */
 531    map_ptrloc ProvidesList;      // Provides
 532
 533    /** \brief archive size for this version
 534
 535        For Debian this is the size of the .deb file. */
 536    unsigned long long Size;      // These are the .deb size
 537    /** \brief uncompressed size for this version */
 538    unsigned long long InstalledSize;
 539    /** \brief characteristic value representing this version
 540
 541        No two packages in existence should have the same VerStr
 542        and Hash with different contents. */
 543    unsigned short Hash;
 544    /** \brief unique sequel ID */
 545    unsigned int ID;
 546    /** \brief parsed priority value */
 547    unsigned char Priority;
 548 };
 549                                                                         /*}}}*/
 550 // Description structure                                                /*{{{*/
 551 /** \brief datamember of a linked list of available description for a version */
 552 struct pkgCache::Description
 553 {
 554    /** \brief Language code of this description (translation)
 555
 556        If the value has a 0 length then this is read using the Package
 557        file else the Translation-CODE file is used. */
 558    map_ptrloc language_code;     // StringItem
 559    /** \brief MD5sum of the original description
 560
 561        Used to map Translations of a description to a version
 562        and to check that the Translation is up-to-date. */
 563    map_ptrloc md5sum;            // StringItem
 564
 565    /* @TODO document pkgCache::Description::FileList */
 566    map_ptrloc FileList;          // DescFile
 567    /** \brief next translation for this description */
 568    map_ptrloc NextDesc;          // Description
 569    /** \brief the text is a description of this package */
 570    map_ptrloc ParentPkg;         // Package
 571
 572    /** \brief unique sequel ID */
 573    unsigned int ID;
 574 };
 575                                                                         /*}}}*/
 576 // Dependency structure                                                 /*{{{*/
 577 /** \brief information for a single dependency record
 578
 579     The records are split up like this to ease processing by the client.
 580     The base of the linked list is pkgCache::Version::DependsList.
 581     All forms of dependencies are recorded here including Depends,
 582     Recommends, Suggests, Enhances, Conflicts, Replaces and Breaks. */
 583 struct pkgCache::Dependency
 584 {
 585    /** \brief string of the version the dependency is applied against */
 586    map_ptrloc Version;         // StringItem
 587    /** \brief index of the package this depends applies to
 588
 589        The generator will - if the package does not already exist -
 590        create a blank (no version records) package. */
 591    map_ptrloc Package;         // Package
 592    /** \brief next dependency of this version */
 593    map_ptrloc NextDepends;     // Dependency
 594    /** \brief next reverse dependency of this package */
 595    map_ptrloc NextRevDepends;  // Dependency
 596    /** \brief version of the package which has the reverse depends */
 597    map_ptrloc ParentVer;       // Version
 598
 599    /** \brief unique sequel ID */
 600    map_ptrloc ID;
 601    /** \brief Dependency type - Depends, Recommends, Conflicts, etc */
 602    unsigned char Type;
 603    /** \brief comparison operator specified on the depends line
 604
 605        If the high bit is set then it is a logical OR with the previous record. */
 606    unsigned char CompareOp;
 607 };
 608                                                                         /*}}}*/
 609 // Provides structure                                                   /*{{{*/
 610 /** \brief handles virtual packages
 611
 612     When a Provides: line is encountered a new provides record is added
 613     associating the package with a virtual package name.
 614     The provides structures are linked off the package structures.
 615     This simplifies the analysis of dependencies and other aspects A provides
 616     refers to a specific version of a specific package, not all versions need to
 617     provide that provides.*/
 618 struct pkgCache::Provides
 619 {
 620    /** \brief index of the package providing this */
 621    map_ptrloc ParentPkg;        // Package
 622    /** \brief index of the version this provide line applies to */
 623    map_ptrloc Version;          // Version
 624    /** \brief version in the provides line (if any)
 625
 626        This version allows dependencies to depend on specific versions of a
 627        Provides, as well as allowing Provides to override existing packages.
 628        This is experimental. Note that Debian doesn't allow versioned provides */
 629    map_ptrloc ProvideVersion;   // StringItem
 630    /** \brief next provides (based of package) */
 631    map_ptrloc NextProvides;     // Provides
 632    /** \brief next provides (based of version) */
 633    map_ptrloc NextPkgProv;      // Provides
 634 };
 635                                                                         /*}}}*/
 636 // StringItem structure                                                 /*{{{*/
 637 /** \brief used for generating single instances of strings
 638
 639     Some things like Section Name are are useful to have as unique tags.
 640     It is part of a linked list based at pkgCache::Header::StringList
 641
 642     All strings are simply inlined any place in the file that is natural
 643     for the writer. The client should make no assumptions about the positioning
 644     of strings. All StringItems should be null-terminated. */
 645 struct pkgCache::StringItem
 646 {
 647    /** \brief string this refers to */
 648    map_ptrloc String;        // StringItem
 649    /** \brief Next link in the chain */
 650    map_ptrloc NextItem;      // StringItem
 651 };
 652                                                                         /*}}}*/
 653
 654
 655 inline char const * const pkgCache::NativeArch() const
 656         { return StrP + HeaderP->Architecture; };
 657
 658 #include <apt-pkg/cacheiterators.h>
 659
 660 inline pkgCache::GrpIterator pkgCache::GrpBegin()
 661        {return GrpIterator(*this);};
 662 inline pkgCache::GrpIterator pkgCache::GrpEnd()
 663        {return GrpIterator(*this,GrpP);};
 664 inline pkgCache::PkgIterator pkgCache::PkgBegin()
 665        {return PkgIterator(*this);};
 666 inline pkgCache::PkgIterator pkgCache::PkgEnd()
 667        {return PkgIterator(*this,PkgP);};
 668 inline pkgCache::PkgFileIterator pkgCache::FileBegin()
 669        {return PkgFileIterator(*this,PkgFileP + HeaderP->FileList);};
 670 inline pkgCache::PkgFileIterator pkgCache::FileEnd()
 671        {return PkgFileIterator(*this,PkgFileP);};
 672
 673 // Oh I wish for Real Name Space Support
 674 class pkgCache::Namespace                                               /*{{{*/
 675 {
 676    public:
 677    typedef pkgCache::GrpIterator GrpIterator;
 678    typedef pkgCache::PkgIterator PkgIterator;
 679    typedef pkgCache::VerIterator VerIterator;
 680    typedef pkgCache::DescIterator DescIterator;
 681    typedef pkgCache::DepIterator DepIterator;
 682    typedef pkgCache::PrvIterator PrvIterator;
 683    typedef pkgCache::PkgFileIterator PkgFileIterator;
 684    typedef pkgCache::VerFileIterator VerFileIterator;
 685    typedef pkgCache::Version Version;
 686    typedef pkgCache::Description Description;
 687    typedef pkgCache::Package Package;
 688    typedef pkgCache::Header Header;
 689    typedef pkgCache::Dep Dep;
 690    typedef pkgCache::Flag Flag;
 691 };
 692                                                                         /*}}}*/
 693 #endif