apt-pkg/policy.h

   1 // -*- mode: cpp; mode: fold -*-
   2 // Description                                                          /*{{{*/
   3 /* ######################################################################
   4
   5    Package Version Policy implementation
   6
   7    This implements the more advanced 'Version 4' APT policy engine. The
   8    standard 'Version 0' engine is included inside the DepCache which is
   9    it's historical location.
  10
  11    The V4 engine allows the user to completly control all aspects of
  12    version selection. There are three primary means to choose a version
  13     * Selection by version match
  14     * Selection by Release file match
  15     * Selection by origin server
  16
  17    Each package may be 'pinned' with a single criteria, which will ultimately
  18    result in the selection of a single version, or no version, for each
  19    package.
  20
  21    Furthermore, the default selection can be influenced by specifying
  22    the ordering of package files. The order is derived by reading the
  23    package file preferences and assigning a priority to each package
  24    file.
  25
  26    A special flag may be set to indicate if no version should be returned
  27    if no matching versions are found, otherwise the default matching
  28    rules are used to locate a hit.
  29
  30    ##################################################################### */
  31                                                                         /*}}}*/
  32 #ifndef PKGLIB_POLICY_H
  33 #define PKGLIB_POLICY_H
  34
  35 #include <apt-pkg/depcache.h>
  36 #include <apt-pkg/pkgcache.h>
  37 #include <apt-pkg/cacheiterators.h>
  38 #include <apt-pkg/versionmatch.h>
  39
  40 #include <vector>
  41 #include <string>
  42
  43 #ifndef APT_8_CLEANER_HEADERS
  44 using std::vector;
  45 #endif
  46
  47 class pkgPolicy : public pkgDepCache::Policy
  48 {
  49    protected:
  50
  51    struct Pin
  52    {
  53       pkgVersionMatch::MatchType Type;
  54       std::string Data;
  55       signed short Priority;
  56       Pin() : Type(pkgVersionMatch::None), Priority(0) {};
  57    };
  58
  59    struct PkgPin : Pin
  60    {
  61       std::string Pkg;
  62       explicit PkgPin(std::string const &Pkg) : Pin(), Pkg(Pkg) {};
  63    };
  64
  65    Pin *Pins;
  66    Pin *VerPins;
  67    signed short *PFPriority;
  68    std::vector<Pin> Defaults;
  69    std::vector<PkgPin> Unmatched;
  70    pkgCache *Cache;
  71    bool StatusOverride;
  72
  73    public:
  74
  75    // Things for manipulating pins
  76    void CreatePin(pkgVersionMatch::MatchType Type,std::string Pkg,
  77                   std::string Data,signed short Priority);
  78    pkgCache::VerIterator GetMatch(pkgCache::PkgIterator const &Pkg);
  79
  80    // Things for the cache interface.
  81    virtual pkgCache::VerIterator GetCandidateVer(pkgCache::PkgIterator const &Pkg) APT_OVERRIDE;
  82    virtual signed short GetPriority(pkgCache::PkgIterator const &Pkg) APT_OVERRIDE;
  83    virtual signed short GetPriority(pkgCache::VerIterator const &Ver, bool ConsiderFiles = true) APT_OVERRIDE;
  84    virtual signed short GetPriority(pkgCache::PkgFileIterator const &File) APT_OVERRIDE;
  85
  86    bool InitDefaults();
  87
  88    explicit pkgPolicy(pkgCache *Owner);
  89    virtual ~pkgPolicy();
  90    private:
  91    void * const d;
  92 };
  93
  94 bool ReadPinFile(pkgPolicy &Plcy, std::string File = "");
  95 bool ReadPinDir(pkgPolicy &Plcy, std::string Dir = "");
  96
  97 #endif