add more dpointer placeholders

[apt.git] / apt-pkg / pkgcache.h

diff --git a/apt-pkg/pkgcache.h b/apt-pkg/pkgcache.h
index c8fe3a8deedb7ebe29108d608fed1cea36caeb77..82a69b2ca5473faccb881bcda946c3f4a9487428 100644 (file)
--- a/apt-pkg/pkgcache.h
+++ b/apt-pkg/pkgcache.h
@@ -1,67 +1,153 @@
 // -*- mode: cpp; mode: fold -*-
 // Description                                                         /*{{{*/
 // -*- mode: cpp; mode: fold -*-
 // Description                                                         /*{{{*/

-// $Id: pkgcache.h,v 1.2 1998/07/04 05:57:36 jgg Exp $
-/* ######################################################################
-   
-   Cache - Structure definitions for the cache file
-   
-   Please see doc/pkglib/cache.sgml for a more detailed description of 
-   this format. Also be sure to keep that file up-to-date!!
-   
+/**\file pkgcache.h
+   \brief pkgCache - Structure definitions for the cache file
+
+   The goal of the cache file is two fold:
+   Firstly to speed loading and processing of the package file array and
+   secondly to reduce memory consumption of the package file array.
+
+   The implementation is aimed at an environment with many primary package
+   files, for instance someone that has a Package file for their CD-ROM, a
+   Package file for the latest version of the distribution on the CD-ROM and a
+   package file for the development version. Always present is the information
+   contained in the status file which might be considered a separate package
+   file.
+
+   Please understand, this is designed as a <b>Cache file</b> it is not meant to be
+   used on any system other than the one it was created for. It is not meant to
+   be authoritative either, i.e. if a system crash or software failure occurs it
+   must be perfectly acceptable for the cache file to be in an inconsistent
+   state. Furthermore at any time the cache file may be erased without losing
+   any information.
+
+   Also the structures and storage layout is optimized for use by the APT
+   and may not be suitable for all purposes. However it should be possible
+   to extend it with associate cache files that contain other information.
+
+   To keep memory use down the cache file only contains often used fields and
+   fields that are inexpensive to store, the Package file has a full list of
+   fields. Also the client may assume that all items are perfectly valid and
+   need not perform checks against their correctness. Removal of information
+   from the cache is possible, but blanks will be left in the file, and
+   unused strings will also be present. The recommended implementation is to
+   simply rebuild the cache each time any of the data files change. It is
+   possible to add a new package file to the cache without any negative side
+   effects.
+
+   <b>Note on Pointer access</b>

    Clients should always use the CacheIterators classes for access to the
    Clients should always use the CacheIterators classes for access to the

-   cache. They provide a simple STL-like method for traversing the links
-   of the datastructure.
-   
-   See pkgcachegen.h for information about generating cache structures.
-   
-   ##################################################################### */
+   cache and the data in it. They also provide a simple STL-like method for
+   traversing the links of the datastructure.
+
+   Every item in every structure is stored as the index to that structure.
+   What this means is that once the files is mmaped every data access has to
+   go through a fix up stage to get a real memory pointer. This is done
+   by taking the index, multiplying it by the type size and then adding
+   it to the start address of the memory block. This sounds complex, but
+   in C it is a single array dereference. Because all items are aligned to
+   their size and indexes are stored as multiples of the size of the structure
+   the format is immediately portable to all possible architectures - BUT the
+   generated files are -NOT-.
+
+   This scheme allows code like this to be written:
+   <example>
+     void *Map = mmap(...);
+     Package *PkgList = (Package *)Map;
+     Header *Head = (Header *)Map;
+     char *Strings = (char *)Map;
+     cout << (Strings + PkgList[Head->HashTable[0]]->Name) << endl;
+   </example>
+   Notice the lack of casting or multiplication. The net result is to return
+   the name of the first package in the first hash bucket, without error
+   checks.
+
+   The generator uses allocation pools to group similarly sized structures in
+   large blocks to eliminate any alignment overhead. The generator also
+   assures that no structures overlap and all indexes are unique. Although
+   at first glance it may seem like there is the potential for two structures
+   to exist at the same point the generator never allows this to happen.
+   (See the discussion of free space pools)
+
+   See \ref pkgcachegen.h for more information about generating cache structures. */

                                                                        /*}}}*/
                                                                        /*}}}*/

-// Header section: pkglib

 #ifndef PKGLIB_PKGCACHE_H
 #define PKGLIB_PKGCACHE_H
 
 #ifndef PKGLIB_PKGCACHE_H
 #define PKGLIB_PKGCACHE_H
 

+

 #include <string>
 #include <time.h>
 #include <string>
 #include <time.h>

-#include <pkglib/mmap.h>
+#include <apt-pkg/mmap.h>

 
 

-class pkgCache
+using std::string;
+    
+class pkgVersioningSystem;
+class pkgCache                                                         /*{{{*/

 {
    public:
    // Cache element predeclarations
    struct Header;
 {
    public:
    // Cache element predeclarations
    struct Header;

+   struct Group;

    struct Package;
    struct PackageFile;
    struct Version;
    struct Package;
    struct PackageFile;
    struct Version;

+   struct Description;

    struct Provides;
    struct Dependency;
    struct StringItem;
    struct Provides;
    struct Dependency;
    struct StringItem;

+   struct VerFile;
+   struct DescFile;

    
    // Iterators
    
    // Iterators

+   template<typename Str, typename Itr> class Iterator;
+   class GrpIterator;

    class PkgIterator;
    class VerIterator;
    class PkgIterator;
    class VerIterator;

+   class DescIterator;

    class DepIterator;
    class PrvIterator;
    class PkgFileIterator;
    class DepIterator;
    class PrvIterator;
    class PkgFileIterator;

-   friend PkgIterator;
-   friend VerIterator;
-   friend DepIterator;
-   friend PrvIterator;
-   friend PkgFileIterator;
-
+   class VerFileIterator;
+   class DescFileIterator;
+   
+   class Namespace;
+   

    // These are all the constants used in the cache structures
    // These are all the constants used in the cache structures

-   enum DepType {Depends=1,PreDepends=2,Suggests=3,Recommends=4,
-                 Conflicts=5,Replaces=6};
-   enum VerPriority {Important=1,Required=2,Standard=3,Optional=5,Extra=5};
-   enum PkgSelectedState {Unknown=0,Install=1,Hold=2,DeInstall=3,Purge=4};
-   enum PkgFlags {Auto=(1<<0),New=(1<<1),Obsolete=(1<<2),Essential=(1<<3),
-                  ImmediateConf=(1<<4)};
-   enum PkgInstState {Ok=0,ReInstReq=1,HoldInst=2,HoldReInstReq=3};
-   enum PkgCurrentState {NotInstalled=0,UnPacked=1,HalfConfigured=2,
-                         UnInstalled=3,HalfInstalled=4,ConfigFiles=5,
-                         Installed=6};
-   enum PkgFFlags {NotSource=(1<<0)};
-   enum DepCompareOp {Or=0x10,LessEq=0x1,GreaterEq=0x2,Less=0x3,
-                      Greater=0x4,Equals=0x5,NotEquals=0x6};
+
+   // WARNING - if you change these lists you must also edit
+   // the stringification in pkgcache.cc and also consider whether
+   // the cache file will become incompatible.
+   struct Dep
+   {
+      enum DepType {Depends=1,PreDepends=2,Suggests=3,Recommends=4,
+        Conflicts=5,Replaces=6,Obsoletes=7,DpkgBreaks=8,Enhances=9};
+      /** \brief available compare operators
+
+          The lower 4 bits are used to indicate what operator is being specified and
+          the upper 4 bits are flags. OR indicates that the next package is
+          or'd with the current package. */
+      enum DepCompareOp {Or=0x10,NoOp=0,LessEq=0x1,GreaterEq=0x2,Less=0x3,
+        Greater=0x4,Equals=0x5,NotEquals=0x6};
+   };
+   
+   struct State
+   {
+      /** \brief priority of a package version
+
+          Zero is used for unparsable or absent Priority fields. */
+      enum VerPriority {Important=1,Required=2,Standard=3,Optional=4,Extra=5};
+      enum PkgSelectedState {Unknown=0,Install=1,Hold=2,DeInstall=3,Purge=4};
+      enum PkgInstState {Ok=0,ReInstReq=1,HoldInst=2,HoldReInstReq=3};
+      enum PkgCurrentState {NotInstalled=0,UnPacked=1,HalfConfigured=2,
+          HalfInstalled=4,ConfigFiles=5,Installed=6,
+           TriggersAwaited=7,TriggersPending=8};
+   };
+   
+   struct Flag
+   {
+      enum PkgFlags {Auto=(1<<0),Essential=(1<<3),Important=(1<<4)};
+      enum PkgFFlags {NotSource=(1<<0),NotAutomatic=(1<<1),ButAutomaticUpgrades=(1<<2)};
+   };

    
    protected:
    
    
    protected:
    


@@ -69,171 +155,533 @@ class pkgCache
    string CacheFile;
    MMap &Map;
 
    string CacheFile;
    MMap &Map;
 

-   bool Public;
-   bool ReadOnly;
-
-   static unsigned long sHash(string S);
-   static unsigned long sHash(const char *S);
+   unsigned long sHash(const string &S) const;
+   unsigned long sHash(const char *S) const;

    
    public:
    
    // Pointers to the arrays of items
    Header *HeaderP;
    
    public:
    
    // Pointers to the arrays of items
    Header *HeaderP;

+   Group *GrpP;

    Package *PkgP;
    Package *PkgP;

+   VerFile *VerFileP;
+   DescFile *DescFileP;

    PackageFile *PkgFileP;
    Version *VerP;
    PackageFile *PkgFileP;
    Version *VerP;

+   Description *DescP;

    Provides *ProvideP;
    Dependency *DepP;
    StringItem *StringItemP;
    char *StrP;
    Provides *ProvideP;
    Dependency *DepP;
    StringItem *StringItemP;
    char *StrP;

-   
-   virtual bool ReMap();
+
+   virtual bool ReMap(bool const &Errorchecks = true);

    inline bool Sync() {return Map.Sync();};
    inline bool Sync() {return Map.Sync();};

-   
+   inline MMap &GetMap() {return Map;};
+   inline void *DataEnd() {return ((unsigned char *)Map.Data()) + Map.Size();};
+      

    // String hashing function (512 range)
    // String hashing function (512 range)

-   inline unsigned long Hash(string S) const {return sHash(S);};
+   inline unsigned long Hash(const string &S) const {return sHash(S);};

    inline unsigned long Hash(const char *S) const {return sHash(S);};
 
    inline unsigned long Hash(const char *S) const {return sHash(S);};
 

+   // Useful transformation things
+   const char *Priority(unsigned char Priority);
+   

    // Accessors
    // Accessors

-   PkgIterator FindPkg(string Name);
+   GrpIterator FindGrp(const string &Name);
+   PkgIterator FindPkg(const string &Name);
+   PkgIterator FindPkg(const string &Name, const string &Arch);
+

    Header &Head() {return *HeaderP;};
    Header &Head() {return *HeaderP;};

+   inline GrpIterator GrpBegin();
+   inline GrpIterator GrpEnd();

    inline PkgIterator PkgBegin();
    inline PkgIterator PkgEnd();
    inline PkgIterator PkgBegin();
    inline PkgIterator PkgEnd();

+   inline PkgFileIterator FileBegin();
+   inline PkgFileIterator FileEnd();
+
+   inline bool MultiArchCache() const { return MultiArchEnabled; };

 
 

-   pkgCache(MMap &Map);
+   // Make me a function
+   pkgVersioningSystem *VS;
+   
+   // Converters
+   static const char *CompTypeDeb(unsigned char Comp);
+   static const char *CompType(unsigned char Comp);
+   static const char *DepType(unsigned char Dep);
+   
+   pkgCache(MMap *Map,bool DoMap = true);

    virtual ~pkgCache() {};
    virtual ~pkgCache() {};

-};

 
 

-// Header structure
+private:
+   bool MultiArchEnabled;
+   PkgIterator SingleArchFindPkg(const string &Name);
+};
+                                                                       /*}}}*/
+// Header structure                                                    /*{{{*/

 struct pkgCache::Header
 {
 struct pkgCache::Header
 {

-   // Signature information
+   /** \brief Signature information
+
+       This must contain the hex value 0x98FE76DC which is designed to
+       verify that the system loading the image has the same byte order
+       and byte size as the system saving the image */

    unsigned long Signature;
    unsigned long Signature;

+   /** These contain the version of the cache file */

    short MajorVersion;
    short MinorVersion;
    short MajorVersion;
    short MinorVersion;

+   /** \brief indicates if the cache should be erased
+
+       Dirty is true if the cache file was opened for reading, the client
+       expects to have written things to it and have not fully synced it.
+       The file should be erased and rebuilt if it is true. */

    bool Dirty;
    bool Dirty;

-   
-   // Size of structure values
+
+   /** \brief Size of structure values
+
+       All *Sz variables contains the sizeof() that particular structure.
+       It is used as an extra consistency check on the structure of the file.
+
+       If any of the size values do not exactly match what the client expects
+       then the client should refuse the load the file. */

    unsigned short HeaderSz;
    unsigned short HeaderSz;

+   unsigned short GroupSz;

    unsigned short PackageSz;
    unsigned short PackageFileSz;
    unsigned short VersionSz;
    unsigned short PackageSz;
    unsigned short PackageFileSz;
    unsigned short VersionSz;

+   unsigned short DescriptionSz;

    unsigned short DependencySz;
    unsigned short ProvidesSz;
    unsigned short DependencySz;
    unsigned short ProvidesSz;

+   unsigned short VerFileSz;
+   unsigned short DescFileSz;
+
+   /** \brief Structure counts

 
 

-   // Structure counts
+       These indicate the number of each structure contained in the cache.
+       PackageCount is especially useful for generating user state structures.
+       See Package::Id for more info. */
+   unsigned long GroupCount;

    unsigned long PackageCount;
    unsigned long VersionCount;
    unsigned long PackageCount;
    unsigned long VersionCount;

+   unsigned long DescriptionCount;

    unsigned long DependsCount;
    unsigned long PackageFileCount;
    unsigned long DependsCount;
    unsigned long PackageFileCount;

-   
-   // Offsets
-   unsigned long FileList;              // struct PackageFile
-   unsigned long StringList;            // struct StringItem
+   unsigned long VerFileCount;
+   unsigned long DescFileCount;
+   unsigned long ProvidesCount;

 
 

-   /* Allocation pools, there should be one of these for each structure
-      excluding the header */
-   DynamicMMap::Pool Pools[6];
+   /** \brief index of the first PackageFile structure
+
+       The PackageFile structures are singly linked lists that represent
+       all package files that have been merged into the cache. */
+   map_ptrloc FileList;
+   /** \brief index of the first StringItem structure
+
+       The cache contains a list of all the unique strings (StringItems).
+       The parser reads this list into memory so it can match strings
+       against it.*/
+   map_ptrloc StringList;
+   /** \brief String representing the version system used */
+   map_ptrloc VerSysName;
+   /** \brief Architecture(s) the cache was built against */
+   map_ptrloc Architecture;
+   /** \brief The maximum size of a raw entry from the original Package file */
+   unsigned long MaxVerFileSize;
+   /** \brief The maximum size of a raw entry from the original Translation file */
+   unsigned long MaxDescFileSize;
+
+   /** \brief The Pool structures manage the allocation pools that the generator uses
+
+       Start indicates the first byte of the pool, Count is the number of objects
+       remaining in the pool and ItemSize is the structure size (alignment factor)
+       of the pool. An ItemSize of 0 indicates the pool is empty. There should be
+       the same number of pools as there are structure types. The generator
+       stores this information so future additions can make use of any unused pool
+       blocks. */
+   DynamicMMap::Pool Pools[9];

    
    

-   // Rapid package name lookup
-   unsigned long HashTable[512];
+   /** \brief hash tables providing rapid group/package name lookup
+
+       Each group/package name is inserted into the hash table using pkgCache::Hash(const &string)
+       By iterating over each entry in the hash table it is possible to iterate over
+       the entire list of packages. Hash Collisions are handled with a singly linked
+       list of packages based at the hash item. The linked list contains only
+       packages that match the hashing function.
+       In the PkgHashTable is it possible that multiple packages have the same name -
+       these packages are stored as a sequence in the list.
+
+       Beware: The Hashmethod assumes that the hash table sizes are equal */
+   map_ptrloc PkgHashTable[2*1048];
+   map_ptrloc GrpHashTable[2*1048];

 
    bool CheckSizes(Header &Against) const;
    Header();
 };
 
    bool CheckSizes(Header &Against) const;
    Header();
 };

+                                                                       /*}}}*/
+// Group structure                                                     /*{{{*/
+/** \brief groups architecture depending packages together

 
 

+    On or more packages with the same name form a group, so we have
+    a simple way to access a package built for different architectures
+    Group exists in a singly linked list of group records starting at
+    the hash index of the name in the pkgCache::Header::GrpHashTable */
+struct pkgCache::Group
+{
+   /** \brief Name of the group */
+   map_ptrloc Name;            // StringItem
+
+   // Linked List
+   /** \brief Link to the first package which belongs to the group */
+   map_ptrloc FirstPackage;    // Package
+   /** \brief Link to the last package which belongs to the group */
+   map_ptrloc LastPackage;     // Package
+   /** \brief Link to the next Group */
+   map_ptrloc Next;            // Group
+   /** \brief unique sequel ID */
+   unsigned int ID;
+
+};
+                                                                       /*}}}*/
+// Package structure                                                   /*{{{*/
+/** \brief contains information for a single unique package
+
+    There can be any number of versions of a given package.
+    Package exists in a singly linked list of package records starting at
+    the hash index of the name in the pkgCache::Header::PkgHashTable
+
+    A package can be created for every architecture so package names are
+    not unique, but it is garanteed that packages with the same name
+    are sequencel ordered in the list. Packages with the same name can be
+    accessed with the Group.
+*/

 struct pkgCache::Package
 {
 struct pkgCache::Package
 {

-   // Pointers
-   unsigned long Name;              // Stringtable
-   unsigned long VersionList;       // Version
-   unsigned long TargetVer;         // Version
-   unsigned long CurrentVer;        // Version
-   unsigned long TargetDist;        // StringTable (StringItem)
-   unsigned long Section;           // StringTable (StringItem)
-      
-   // Linked list 
-   unsigned long NextPackage;       // Package
-   unsigned long RevDepends;        // Dependency
-   unsigned long ProvidesList;      // Provides
-   
+   /** \brief Name of the package */
+   map_ptrloc Name;              // StringItem
+   /** \brief Architecture of the package */
+   map_ptrloc Arch;              // StringItem
+   /** \brief Base of a singly linked list of versions
+
+       Each structure represents a unique version of the package.
+       The version structures contain links into PackageFile and the
+       original text file as well as detailed information about the size
+       and dependencies of the specific package. In this way multiple
+       versions of a package can be cleanly handled by the system.
+       Furthermore, this linked list is guaranteed to be sorted
+       from Highest version to lowest version with no duplicate entries. */
+   map_ptrloc VersionList;       // Version
+   /** \brief index to the installed version */
+   map_ptrloc CurrentVer;        // Version
+   /** \brief indicates the deduced section
+
+       Should be the index to the string "Unknown" or to the section
+       of the last parsed item. */
+   map_ptrloc Section;           // StringItem
+   /** \brief index of the group this package belongs to */
+   map_ptrloc Group;             // Group the Package belongs to
+
+   // Linked list
+   /** \brief Link to the next package in the same bucket */
+   map_ptrloc NextPackage;       // Package
+   /** \brief List of all dependencies on this package */
+   map_ptrloc RevDepends;        // Dependency
+   /** \brief List of all "packages" this package provide */
+   map_ptrloc ProvidesList;      // Provides
+

    // Install/Remove/Purge etc
    // Install/Remove/Purge etc

+   /** \brief state that the user wishes the package to be in */

    unsigned char SelectedState;     // What
    unsigned char SelectedState;     // What

+   /** \brief installation state of the package
+
+       This should be "ok" but in case the installation failed
+       it will be different.
+   */

    unsigned char InstState;         // Flags
    unsigned char InstState;         // Flags

+   /** \brief indicates if the package is installed */

    unsigned char CurrentState;      // State
    unsigned char CurrentState;      // State

-   
-   unsigned short ID;
+
+   /** \brief unique sequel ID
+
+       ID is a unique value from 0 to Header->PackageCount assigned by the generator.
+       This allows clients to create an array of size PackageCount and use it to store
+       state information for the package map. For instance the status file emitter uses
+       this to track which packages have been emitted already. */
+   unsigned int ID;
+   /** \brief some useful indicators of the package's state */

    unsigned long Flags;
 };
    unsigned long Flags;
 };

+                                                                       /*}}}*/
+// Package File structure                                              /*{{{*/
+/** \brief stores information about the files used to generate the cache

 
 

+    Package files are referenced by Version structures to be able to know
+    after the generation still from which Packages file includes this Version
+    as we need this information later on e.g. for pinning. */

 struct pkgCache::PackageFile
 {
 struct pkgCache::PackageFile
 {

-   // Names
-   unsigned long FileName;        // Stringtable
-   unsigned long Version;         // Stringtable
-   unsigned long Distribution;    // Stringtable
+   /** \brief physical disk file that this PackageFile represents */
+   map_ptrloc FileName;        // StringItem
+   /** \brief the release information
+
+       Please see the files document for a description of what the
+       release information means. */
+   map_ptrloc Archive;         // StringItem
+   map_ptrloc Codename;        // StringItem
+   map_ptrloc Component;       // StringItem
+   map_ptrloc Version;         // StringItem
+   map_ptrloc Origin;          // StringItem
+   map_ptrloc Label;           // StringItem
+   map_ptrloc Architecture;    // StringItem
+   /** \brief The site the index file was fetched from */
+   map_ptrloc Site;            // StringItem
+   /** \brief indicates what sort of index file this is
+
+       @TODO enumerate at least the possible indexes */
+   map_ptrloc IndexType;       // StringItem
+   /** \brief Size of the file
+
+       Used together with the modification time as a
+       simple check to ensure that the Packages
+       file has not been altered since Cache generation. */

    unsigned long Size;
    unsigned long Size;

-   
-   // Linked list
-   unsigned long NextFile;        // PackageFile
-   unsigned short ID;
+   /** \brief Modification time for the file */
+   time_t mtime;
+
+   /* @TODO document PackageFile::Flags */

    unsigned long Flags;
    unsigned long Flags;

-   time_t mtime;                  // Modification time for the file
+
+   // Linked list
+   /** \brief Link to the next PackageFile in the Cache */
+   map_ptrloc NextFile;        // PackageFile
+   /** \brief unique sequel ID */
+   unsigned int ID;

 };
 };

+                                                                       /*}}}*/
+// VerFile structure                                                   /*{{{*/
+/** \brief associates a version with a PackageFile

 
 

-struct pkgCache::Version
+    This allows a full description of all Versions in all files
+    (and hence all sources) under consideration. */
+struct pkgCache::VerFile

 {
 {

-   unsigned long VerStr;            // Stringtable
-   unsigned long File;              // PackageFile
-   unsigned long Section;           // StringTable (StringItem)
-   
-   // Lists
-   unsigned long NextVer;           // Version
-   unsigned long DependsList;       // Dependency
-   unsigned long ParentPkg;         // Package
-   unsigned long ProvidesList;      // Provides
-   
-   unsigned long Offset;
+   /** \brief index of the package file that this version was found in */
+   map_ptrloc File;           // PackageFile
+   /** \brief next step in the linked list */
+   map_ptrloc NextFile;       // PkgVerFile
+   /** \brief position in the package file */
+   map_ptrloc Offset;         // File offset
+   /* @TODO document pkgCache::VerFile::Size */

    unsigned long Size;
    unsigned long Size;

-   unsigned long InstalledSize;
-   unsigned short ID;
+};
+                                                                       /*}}}*/
+// DescFile structure                                                  /*{{{*/
+/** \brief associates a description with a Translation file */
+struct pkgCache::DescFile
+{
+   /** \brief index of the file that this description was found in */
+   map_ptrloc File;           // PackageFile
+   /** \brief next step in the linked list */
+   map_ptrloc NextFile;       // PkgVerFile
+   /** \brief position in the file */
+   map_ptrloc Offset;         // File offset
+   /* @TODO document pkgCache::DescFile::Size */
+   unsigned long Size;
+};
+                                                                       /*}}}*/
+// Version structure                                                   /*{{{*/
+/** \brief information for a single version of a package
+
+    The version list is always sorted from highest version to lowest
+    version by the generator. Equal version numbers are either merged
+    or handled as separate versions based on the Hash value. */
+struct pkgCache::Version
+{
+   /** \brief complete version string */
+   map_ptrloc VerStr;            // StringItem
+   /** \brief section this version is filled in */
+   map_ptrloc Section;           // StringItem
+   /** \brief stores the MultiArch capabilities of this version
+
+       None is the default and doesn't trigger special behaviour,
+       Foreign means that this version can fulfill dependencies even
+       if it is built for another architecture as the requester.
+       Same indicates that builds for different architectures can
+       be co-installed on the system and All is the marker for a
+       version with the Architecture: all. */
+   enum {None, All, Foreign, Same, Allowed} MultiArch;
+
+   /** \brief references all the PackageFile's that this version came from
+
+       FileList can be used to determine what distribution(s) the Version
+       applies to. If FileList is 0 then this is a blank version.
+       The structure should also have a 0 in all other fields excluding
+       pkgCache::Version::VerStr and Possibly pkgCache::Version::NextVer. */
+   map_ptrloc FileList;          // VerFile
+   /** \brief next (lower or equal) version in the linked list */
+   map_ptrloc NextVer;           // Version
+   /** \brief next description in the linked list */
+   map_ptrloc DescriptionList;   // Description
+   /** \brief base of the dependency list */
+   map_ptrloc DependsList;       // Dependency
+   /** \brief links to the owning package
+
+       This allows reverse dependencies to determine the package */
+   map_ptrloc ParentPkg;         // Package
+   /** \brief list of pkgCache::Provides */
+   map_ptrloc ProvidesList;      // Provides
+
+   /** \brief archive size for this version
+
+       For Debian this is the size of the .deb file. */
+   unsigned long long Size;      // These are the .deb size
+   /** \brief uncompressed size for this version */
+   unsigned long long InstalledSize;
+   /** \brief characteristic value representing this version
+
+       No two packages in existence should have the same VerStr
+       and Hash with different contents. */
+   unsigned short Hash;
+   /** \brief unique sequel ID */
+   unsigned int ID;
+   /** \brief parsed priority value */

    unsigned char Priority;
 };
    unsigned char Priority;
 };

+                                                                       /*}}}*/
+// Description structure                                               /*{{{*/
+/** \brief datamember of a linked list of available description for a version */
+struct pkgCache::Description
+{
+   /** \brief Language code of this description (translation)
+
+       If the value has a 0 length then this is read using the Package
+       file else the Translation-CODE file is used. */
+   map_ptrloc language_code;     // StringItem
+   /** \brief MD5sum of the original description
+
+       Used to map Translations of a description to a version
+       and to check that the Translation is up-to-date. */
+   map_ptrloc md5sum;            // StringItem
+
+   /* @TODO document pkgCache::Description::FileList */
+   map_ptrloc FileList;          // DescFile
+   /** \brief next translation for this description */
+   map_ptrloc NextDesc;          // Description
+   /** \brief the text is a description of this package */
+   map_ptrloc ParentPkg;         // Package
+
+   /** \brief unique sequel ID */
+   unsigned int ID;
+};
+                                                                       /*}}}*/
+// Dependency structure                                                        /*{{{*/
+/** \brief information for a single dependency record

 
 

+    The records are split up like this to ease processing by the client.
+    The base of the linked list is pkgCache::Version::DependsList.
+    All forms of dependencies are recorded here including Depends,
+    Recommends, Suggests, Enhances, Conflicts, Replaces and Breaks. */

 struct pkgCache::Dependency
 {
 struct pkgCache::Dependency
 {

-   unsigned long Version;         // Stringtable
-   unsigned long Package;         // Package
-   unsigned long NextDepends;     // Dependency
-   unsigned long NextRevDepends;  // Dependency
-   unsigned long ParentVer;       // Version
-   
-   // Specific types of depends
+   /** \brief string of the version the dependency is applied against */
+   map_ptrloc Version;         // StringItem
+   /** \brief index of the package this depends applies to
+
+       The generator will - if the package does not already exist -
+       create a blank (no version records) package. */
+   map_ptrloc Package;         // Package
+   /** \brief next dependency of this version */
+   map_ptrloc NextDepends;     // Dependency
+   /** \brief next reverse dependency of this package */
+   map_ptrloc NextRevDepends;  // Dependency
+   /** \brief version of the package which has the reverse depends */
+   map_ptrloc ParentVer;       // Version
+
+   /** \brief unique sequel ID */
+   map_ptrloc ID;
+   /** \brief Dependency type - Depends, Recommends, Conflicts, etc */

    unsigned char Type;
    unsigned char Type;

+   /** \brief comparison operator specified on the depends line
+
+       If the high bit is set then it is a logical OR with the previous record. */

    unsigned char CompareOp;
    unsigned char CompareOp;

-   unsigned short ID;

 };
 };

+                                                                       /*}}}*/
+// Provides structure                                                  /*{{{*/
+/** \brief handles virtual packages

 
 

+    When a Provides: line is encountered a new provides record is added
+    associating the package with a virtual package name.
+    The provides structures are linked off the package structures.
+    This simplifies the analysis of dependencies and other aspects A provides
+    refers to a specific version of a specific package, not all versions need to
+    provide that provides.*/

 struct pkgCache::Provides
 {
 struct pkgCache::Provides
 {

-   unsigned long ParentPkg;        // Pacakge
-   unsigned long Version;          // Version
-   unsigned long ProvideVersion;   // Stringtable
-   unsigned long NextProvides;     // Provides
-   unsigned long NextPkgProv;      // Provides
+   /** \brief index of the package providing this */
+   map_ptrloc ParentPkg;        // Package
+   /** \brief index of the version this provide line applies to */
+   map_ptrloc Version;          // Version
+   /** \brief version in the provides line (if any)
+
+       This version allows dependencies to depend on specific versions of a
+       Provides, as well as allowing Provides to override existing packages.
+       This is experimental. Note that Debian doesn't allow versioned provides */
+   map_ptrloc ProvideVersion;   // StringItem
+   /** \brief next provides (based of package) */
+   map_ptrloc NextProvides;     // Provides
+   /** \brief next provides (based of version) */
+   map_ptrloc NextPkgProv;      // Provides

 };
 };

+                                                                       /*}}}*/
+// StringItem structure                                                        /*{{{*/
+/** \brief used for generating single instances of strings
+
+    Some things like Section Name are are useful to have as unique tags.
+    It is part of a linked list based at pkgCache::Header::StringList

 
 

+    All strings are simply inlined any place in the file that is natural
+    for the writer. The client should make no assumptions about the positioning
+    of strings. All StringItems should be null-terminated. */

 struct pkgCache::StringItem
 {
 struct pkgCache::StringItem
 {

-   unsigned long String;        // Stringtable
-   unsigned long NextItem;      // StringItem
+   /** \brief string this refers to */
+   map_ptrloc String;        // StringItem
+   /** \brief Next link in the chain */
+   map_ptrloc NextItem;      // StringItem

 };
 };

+                                                                       /*}}}*/
+#include <apt-pkg/cacheiterators.h>

 
 

-#include <pkglib/cacheiterators.h>
-
+inline pkgCache::GrpIterator pkgCache::GrpBegin() 
+       {return GrpIterator(*this);};
+inline pkgCache::GrpIterator pkgCache::GrpEnd() 
+       {return GrpIterator(*this,GrpP);};

 inline pkgCache::PkgIterator pkgCache::PkgBegin() 
        {return PkgIterator(*this);};
 inline pkgCache::PkgIterator pkgCache::PkgEnd() 
        {return PkgIterator(*this,PkgP);};
 inline pkgCache::PkgIterator pkgCache::PkgBegin() 
        {return PkgIterator(*this);};
 inline pkgCache::PkgIterator pkgCache::PkgEnd() 
        {return PkgIterator(*this,PkgP);};

+inline pkgCache::PkgFileIterator pkgCache::FileBegin()
+       {return PkgFileIterator(*this,PkgFileP + HeaderP->FileList);};
+inline pkgCache::PkgFileIterator pkgCache::FileEnd()
+       {return PkgFileIterator(*this,PkgFileP);};

 
 

+// Oh I wish for Real Name Space Support
+class pkgCache::Namespace                                              /*{{{*/
+{   
+   public:
+   typedef pkgCache::GrpIterator GrpIterator;
+   typedef pkgCache::PkgIterator PkgIterator;
+   typedef pkgCache::VerIterator VerIterator;
+   typedef pkgCache::DescIterator DescIterator;
+   typedef pkgCache::DepIterator DepIterator;
+   typedef pkgCache::PrvIterator PrvIterator;
+   typedef pkgCache::PkgFileIterator PkgFileIterator;
+   typedef pkgCache::VerFileIterator VerFileIterator;   
+   typedef pkgCache::Version Version;
+   typedef pkgCache::Description Description;
+   typedef pkgCache::Package Package;
+   typedef pkgCache::Header Header;
+   typedef pkgCache::Dep Dep;
+   typedef pkgCache::Flag Flag;
+};
+                                                                       /*}}}*/

 #endif
 #endif