apt-pkg/policy.cc

   1 // -*- mode: cpp; mode: fold -*-
   2 // Description                                                          /*{{{*/
   3 // $Id: policy.cc,v 1.3 2001/03/03 23:27:24 jgg Exp $
   4 /* ######################################################################
   5
   6    Package Version Policy implementation
   7
   8    This is just a really simple wrapper around pkgVersionMatch with
   9    some added goodies to manage the list of things..
  10
  11    Priority Table:
  12
  13    1000 -> inf = Downgradeable priorities
  14    1000        = The 'no downgrade' pseduo-status file
  15    100 -> 1000 = Standard priorities
  16    990         = Config file override package files
  17    989         = Start for preference auto-priorities
  18    500         = Default package files
  19    100         = The status file
  20    0 -> 100    = NotAutomatic sources like experimental
  21    -inf -> 0   = Never selected
  22
  23    ##################################################################### */
  24                                                                         /*}}}*/
  25 // Include Files                                                        /*{{{*/
  26 #ifdef __GNUG__
  27 #pragma implementation "apt-pkg/policy.h"
  28 #endif
  29 #include <apt-pkg/policy.h>
  30 #include <apt-pkg/configuration.h>
  31 #include <apt-pkg/tagfile.h>
  32 #include <apt-pkg/strutl.h>
  33 #include <apt-pkg/error.h>
  34 #include <apt-pkg/sptr.h>
  35
  36 #include <apti18n.h>
  37                                                                         /*}}}*/
  38
  39 // Policy::Init - Startup and bind to a cache                           /*{{{*/
  40 // ---------------------------------------------------------------------
  41 /* Set the defaults for operation. The default mode with no loaded policy
  42    file matches the V0 policy engine. */
  43 pkgPolicy::pkgPolicy(pkgCache *Owner) : Pins(0), PFPriority(0), Cache(Owner)
  44 {
  45    PFPriority = new signed short[Owner->Head().PackageFileCount];
  46    Pins = new Pin[Owner->Head().PackageCount];
  47
  48    for (unsigned long I = 0; I != Owner->Head().PackageCount; I++)
  49       Pins[I].Type = pkgVersionMatch::None;
  50
  51    // The config file has a master override.
  52    string DefRel = _config->Find("APT::Default-Release");
  53    if (DefRel.empty() == false)
  54       CreatePin(pkgVersionMatch::Release,"",DefRel,990);
  55
  56    InitDefaults();
  57 }
  58                                                                         /*}}}*/
  59 // Policy::InitDefaults - Compute the default selections                /*{{{*/
  60 // ---------------------------------------------------------------------
  61 /* */
  62 bool pkgPolicy::InitDefaults()
  63 {
  64    // Initialize the priorities based on the status of the package file
  65    for (pkgCache::PkgFileIterator I = Cache->FileBegin(); I != Cache->FileEnd(); I++)
  66    {
  67       PFPriority[I->ID] = 500;
  68       if ((I->Flags & pkgCache::Flag::NotSource) == pkgCache::Flag::NotSource)
  69          PFPriority[I->ID] = 100;
  70       else
  71          if ((I->Flags & pkgCache::Flag::NotAutomatic) == pkgCache::Flag::NotAutomatic)
  72             PFPriority[I->ID] = 1;
  73    }
  74
  75    // Apply the defaults..
  76    SPtr<bool> Fixed = new bool[Cache->HeaderP->PackageFileCount];
  77    memset(Fixed,0,sizeof(*Fixed)*Cache->HeaderP->PackageFileCount);
  78    signed Cur = 989;
  79    StatusOverride = false;
  80    for (vector<Pin>::const_iterator I = Defaults.begin(); I != Defaults.end();
  81         I++, Cur--)
  82    {
  83       pkgVersionMatch Match(I->Data,I->Type);
  84       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); F++)
  85       {
  86 /* hmm?
  87  if ((F->Flags & pkgCache::Flag::NotSource) == pkgCache::Flag::NotSource)
  88             continue;*/
  89
  90          if (Match.FileMatch(F) == true && Fixed[F->ID] == false)
  91          {
  92             if (I->Priority != 0 && I->Priority > 0)
  93                Cur = I->Priority;
  94
  95             if (I->Priority < 0)
  96                PFPriority[F->ID] =  I->Priority;
  97             else
  98                PFPriority[F->ID] = Cur;
  99
 100             if (PFPriority[F->ID] > 1000)
 101                StatusOverride = true;
 102
 103             Fixed[F->ID] = true;
 104          }
 105       }
 106    }
 107
 108    if (_config->FindB("Debug::pkgPolicy",false) == true)
 109       for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); F++)
 110          cout << "Prio of " << F.FileName() << ' ' << PFPriority[F->ID] << endl;
 111
 112    return true;
 113 }
 114                                                                         /*}}}*/
 115 // Policy::GetCandidateVer - Get the candidate install version          /*{{{*/
 116 // ---------------------------------------------------------------------
 117 /* Evaluate the package pins and the default list to deteremine what the
 118    best package is. */
 119 pkgCache::VerIterator pkgPolicy::GetCandidateVer(pkgCache::PkgIterator Pkg)
 120 {
 121    const Pin &PPkg = Pins[Pkg->ID];
 122
 123    // Look for a package pin and evaluate it.
 124    signed Max = 0;
 125    pkgCache::VerIterator Pref(*Cache);
 126    if (PPkg.Type != pkgVersionMatch::None)
 127    {
 128       pkgVersionMatch Match(PPkg.Data,PPkg.Type);
 129       Pref = Match.Find(Pkg);
 130       Max = PPkg.Priority;
 131       if (PPkg.Priority == 0)
 132          Max = 989;
 133    }
 134
 135    /* Falling through to the default version.. Setting Max to zero
 136       effectively excludes everything <= 0 which are the non-automatic
 137       priorities.. The status file is given a prio of 100 which will exclude
 138       not-automatic sources, except in a single shot not-installed mode.
 139       The second pseduo-status file is at prio 1000, above which will permit
 140       the user to force-downgrade things.
 141
 142       The user pin is subject to the same priority rules as default
 143       selections. Thus there are two ways to create a pin - a pin that
 144       tracks the default when the default is taken away, and a permanent
 145       pin that stays at that setting.
 146     */
 147    for (pkgCache::VerIterator Ver = Pkg.VersionList(); Ver.end() == false; Ver++)
 148    {
 149       /* This is a side effect of the condition below, and is added for
 150          completeness, though it should not be necessary */
 151       if (Ver->Arch == 0)
 152          continue;
 153
 154       for (pkgCache::VerFileIterator VF = Ver.FileList(); VF.end() == false; VF++)
 155       {
 156          /* If this is the status file, and the current version is not the
 157             version in the status file (ie it is not installed, or somesuch)
 158             then it is not a candidate for installation, ever. This weeds
 159             out bogus entries that may be due to config-file states, or
 160             other. */
 161          if ((VF.File()->Flags & pkgCache::Flag::NotSource) == pkgCache::Flag::NotSource &&
 162              Pkg.CurrentVer() != Ver)
 163             continue;
 164
 165          signed Prio = PFPriority[VF.File()->ID];
 166          if (Prio > Max)
 167          {
 168             Pref = Ver;
 169             Max = Prio;
 170          }
 171       }
 172
 173       if (Pkg.CurrentVer() == Ver && Max < 1000)
 174       {
 175          /* Elevate our current selection (or the status file itself)
 176             to the Pseudo-status priority. */
 177          if (Pref.end() == true)
 178             Pref = Ver;
 179          Max = 1000;
 180
 181          // Fast path optimize.
 182          if (StatusOverride == false)
 183             break;
 184       }
 185    }
 186
 187    return Pref;
 188 }
 189                                                                         /*}}}*/
 190 // Policy::CreatePin - Create an entry in the pin table..               /*{{{*/
 191 // ---------------------------------------------------------------------
 192 /* For performance we have 3 tables, the default table, the main cache
 193    table (hashed to the cache). A blank package name indicates the pin
 194    belongs to the default table. Order of insertion matters here, the
 195    earlier defaults override later ones. */
 196 void pkgPolicy::CreatePin(pkgVersionMatch::MatchType Type,string Name,
 197                           string Data,signed short Priority)
 198 {
 199    pkgCache::PkgIterator Pkg = Cache->FindPkg(Name);
 200    Pin *P = 0;
 201
 202    if (Name.empty() == true)
 203       P = Defaults.insert(Defaults.end());
 204    else
 205    {
 206       // Get a spot to put the pin
 207       if (Pkg.end() == true)
 208       {
 209          // Check the unmatched table
 210          for (vector<PkgPin>::iterator I = Unmatched.begin();
 211               I != Unmatched.end() && P == 0; I++)
 212             if (I->Pkg == Name)
 213                P = I;
 214
 215          if (P == 0)
 216             P = Unmatched.insert(Unmatched.end());
 217       }
 218       else
 219       {
 220          P = Pins + Pkg->ID;
 221       }
 222    }
 223
 224    // Set..
 225    P->Type = Type;
 226    P->Priority = Priority;
 227    P->Data = Data;
 228 }
 229                                                                         /*}}}*/
 230
 231 // ReadPinFile - Load the pin file into a Policy                        /*{{{*/
 232 // ---------------------------------------------------------------------
 233 /* I'd like to see the preferences file store more than just pin information
 234    but right now that is the only stuff I have to store. Later there will
 235    have to be some kind of combined super parser to get the data into all
 236    the right classes.. */
 237 bool ReadPinFile(pkgPolicy &Plcy,string File)
 238 {
 239    if (File.empty() == true)
 240       File = _config->FindFile("Dir::Etc::Preferences");
 241
 242    if (FileExists(File) == false)
 243       return true;
 244
 245    FileFd Fd(File,FileFd::ReadOnly);
 246    pkgTagFile TF(&Fd);
 247    if (_error->PendingError() == true)
 248       return false;
 249
 250    pkgTagSection Tags;
 251    while (TF.Step(Tags) == true)
 252    {
 253       string Name = Tags.FindS("Package");
 254       if (Name.empty() == true)
 255          return _error->Error(_("Invalid record in the preferences file, no Package header"));
 256       if (Name == "*")
 257          Name = string();
 258
 259       const char *Start;
 260       const char *End;
 261       if (Tags.Find("Pin",Start,End) == false)
 262          continue;
 263
 264       const char *Word = Start;
 265       for (; Word != End && isspace(*Word) == 0; Word++);
 266
 267       // Parse the type..
 268       pkgVersionMatch::MatchType Type;
 269       if (stringcasecmp(Start,Word,"version") == 0 && Name.empty() == false)
 270          Type = pkgVersionMatch::Version;
 271       else if (stringcasecmp(Start,Word,"release") == 0)
 272          Type = pkgVersionMatch::Release;
 273       else if (stringcasecmp(Start,Word,"origin") == 0)
 274          Type = pkgVersionMatch::Origin;
 275       else
 276       {
 277          _error->Warning(_("Did not understand pin type %s"),string(Start,Word).c_str());
 278          continue;
 279       }
 280       for (; Word != End && isspace(*Word) != 0; Word++);
 281
 282       Plcy.CreatePin(Type,Name,string(Word,End),
 283                      Tags.FindI("Pin-Priority"));
 284    }
 285
 286    Plcy.InitDefaults();
 287    return true;
 288 }
 289                                                                         /*}}}*/