apt-pkg/algorithms.cc

   1 // -*- mode: cpp; mode: fold -*-
   2 // Description                                                          /*{{{*/
   3 // $Id: algorithms.cc,v 1.44 2002/11/28 18:49:16 jgg Exp $
   4 /* ######################################################################
   5
   6    Algorithms - A set of misc algorithms
   7
   8    The pkgProblemResolver class has become insanely complex and
   9    very sophisticated, it handles every test case I have thrown at it
  10    to my satisfaction. Understanding exactly why all the steps the class
  11    does are required is difficult and changing though not very risky
  12    may result in other cases not working.
  13
  14    ##################################################################### */
  15                                                                         /*}}}*/
  16 // Include Files                                                        /*{{{*/
  17 #include <config.h>
  18
  19 #include <apt-pkg/algorithms.h>
  20 #include <apt-pkg/error.h>
  21 #include <apt-pkg/configuration.h>
  22 #include <apt-pkg/sptr.h>
  23 #include <apt-pkg/edsp.h>
  24 #include <apt-pkg/progress.h>
  25 #include <apt-pkg/depcache.h>
  26 #include <apt-pkg/packagemanager.h>
  27 #include <apt-pkg/pkgcache.h>
  28 #include <apt-pkg/cacheiterators.h>
  29
  30 #include <string.h>
  31 #include <string>
  32 #include <cstdlib>
  33 #include <iostream>
  34
  35 #include <apti18n.h>
  36                                                                         /*}}}*/
  37 using namespace std;
  38
  39 pkgProblemResolver *pkgProblemResolver::This = 0;
  40
  41 // Simulate::Simulate - Constructor                                     /*{{{*/
  42 // ---------------------------------------------------------------------
  43 /* The legacy translations here of input Pkg iterators is obsolete,
  44    this is not necessary since the pkgCaches are fully shared now. */
  45 pkgSimulate::pkgSimulate(pkgDepCache *Cache) : pkgPackageManager(Cache),
  46                             iPolicy(Cache),
  47                             Sim(&Cache->GetCache(),&iPolicy),
  48                             group(Sim)
  49 {
  50    Sim.Init(0);
  51    Flags = new unsigned char[Cache->Head().PackageCount];
  52    memset(Flags,0,sizeof(*Flags)*Cache->Head().PackageCount);
  53
  54    // Fake a filename so as not to activate the media swapping
  55    string Jnk = "SIMULATE";
  56    for (unsigned int I = 0; I != Cache->Head().PackageCount; I++)
  57       FileNames[I] = Jnk;
  58 }
  59                                                                         /*}}}*/
  60 // Simulate::~Simulate - Destructor                                     /*{{{*/
  61 pkgSimulate::~pkgSimulate()
  62 {
  63    delete[] Flags;
  64 }
  65                                                                         /*}}}*/
  66 // Simulate::Describe - Describe a package                              /*{{{*/
  67 // ---------------------------------------------------------------------
  68 /* Parameter Current == true displays the current package version,
  69    Parameter Candidate == true displays the candidate package version */
  70 void pkgSimulate::Describe(PkgIterator Pkg,ostream &out,bool Current,bool Candidate)
  71 {
  72    VerIterator Ver(Sim);
  73
  74    out << Pkg.FullName(true);
  75
  76    if (Current == true)
  77    {
  78       Ver = Pkg.CurrentVer();
  79       if (Ver.end() == false)
  80          out << " [" << Ver.VerStr() << ']';
  81    }
  82
  83    if (Candidate == true)
  84    {
  85       Ver = Sim[Pkg].CandidateVerIter(Sim);
  86       if (Ver.end() == true)
  87          return;
  88
  89       out << " (" << Ver.VerStr() << ' ' << Ver.RelStr() << ')';
  90    }
  91 }
  92                                                                         /*}}}*/
  93 // Simulate::Install - Simulate unpacking of a package                  /*{{{*/
  94 // ---------------------------------------------------------------------
  95 /* */
  96 bool pkgSimulate::Install(PkgIterator iPkg,string /*File*/)
  97 {
  98    // Adapt the iterator
  99    PkgIterator Pkg = Sim.FindPkg(iPkg.Name(), iPkg.Arch());
 100    Flags[Pkg->ID] = 1;
 101
 102    cout << "Inst ";
 103    Describe(Pkg,cout,true,true);
 104    Sim.MarkInstall(Pkg,false);
 105
 106    // Look for broken conflicts+predepends.
 107    for (PkgIterator I = Sim.PkgBegin(); I.end() == false; ++I)
 108    {
 109       if (Sim[I].InstallVer == 0)
 110          continue;
 111
 112       for (DepIterator D = Sim[I].InstVerIter(Sim).DependsList(); D.end() == false;)
 113       {
 114          DepIterator Start;
 115          DepIterator End;
 116          D.GlobOr(Start,End);
 117          if (Start.IsNegative() == true ||
 118              End->Type == pkgCache::Dep::PreDepends)
 119          {
 120             if ((Sim[End] & pkgDepCache::DepGInstall) == 0)
 121             {
 122                cout << " [" << I.FullName(false) << " on " << Start.TargetPkg().FullName(false) << ']';
 123                if (Start->Type == pkgCache::Dep::Conflicts)
 124                   _error->Error("Fatal, conflicts violated %s",I.FullName(false).c_str());
 125             }
 126          }
 127       }
 128    }
 129
 130    if (Sim.BrokenCount() != 0)
 131       ShortBreaks();
 132    else
 133       cout << endl;
 134    return true;
 135 }
 136                                                                         /*}}}*/
 137 // Simulate::Configure - Simulate configuration of a Package            /*{{{*/
 138 // ---------------------------------------------------------------------
 139 /* This is not an acurate simulation of relatity, we should really not
 140    install the package.. For some investigations it may be necessary
 141    however. */
 142 bool pkgSimulate::Configure(PkgIterator iPkg)
 143 {
 144    // Adapt the iterator
 145    PkgIterator Pkg = Sim.FindPkg(iPkg.Name(), iPkg.Arch());
 146
 147    Flags[Pkg->ID] = 2;
 148
 149    if (Sim[Pkg].InstBroken() == true)
 150    {
 151       cout << "Conf " << Pkg.FullName(false) << " broken" << endl;
 152
 153       Sim.Update();
 154
 155       // Print out each package and the failed dependencies
 156       for (pkgCache::DepIterator D = Sim[Pkg].InstVerIter(Sim).DependsList(); D.end() == false; ++D)
 157       {
 158          if (Sim.IsImportantDep(D) == false ||
 159              (Sim[D] & pkgDepCache::DepInstall) != 0)
 160             continue;
 161
 162          if (D->Type == pkgCache::Dep::Obsoletes)
 163             cout << " Obsoletes:" << D.TargetPkg().FullName(false);
 164          else if (D->Type == pkgCache::Dep::Conflicts)
 165             cout << " Conflicts:" << D.TargetPkg().FullName(false);
 166          else if (D->Type == pkgCache::Dep::DpkgBreaks)
 167             cout << " Breaks:" << D.TargetPkg().FullName(false);
 168          else
 169             cout << " Depends:" << D.TargetPkg().FullName(false);
 170       }
 171       cout << endl;
 172
 173       _error->Error("Conf Broken %s",Pkg.FullName(false).c_str());
 174    }
 175    else
 176    {
 177       cout << "Conf ";
 178       Describe(Pkg,cout,false,true);
 179    }
 180
 181    if (Sim.BrokenCount() != 0)
 182       ShortBreaks();
 183    else
 184       cout << endl;
 185
 186    return true;
 187 }
 188                                                                         /*}}}*/
 189 // Simulate::Remove - Simulate the removal of a package                 /*{{{*/
 190 // ---------------------------------------------------------------------
 191 /* */
 192 bool pkgSimulate::Remove(PkgIterator iPkg,bool Purge)
 193 {
 194    // Adapt the iterator
 195    PkgIterator Pkg = Sim.FindPkg(iPkg.Name(), iPkg.Arch());
 196    if (Pkg.end() == true)
 197    {
 198       std::cerr << (Purge ? "Purg" : "Remv") << " invalid package " << iPkg.FullName() << std::endl;
 199       return false;
 200    }
 201
 202    Flags[Pkg->ID] = 3;
 203    Sim.MarkDelete(Pkg);
 204
 205    if (Purge == true)
 206       cout << "Purg ";
 207    else
 208       cout << "Remv ";
 209    Describe(Pkg,cout,true,false);
 210
 211    if (Sim.BrokenCount() != 0)
 212       ShortBreaks();
 213    else
 214       cout << endl;
 215
 216    return true;
 217 }
 218                                                                         /*}}}*/
 219 // Simulate::ShortBreaks - Print out a short line describing all breaks /*{{{*/
 220 // ---------------------------------------------------------------------
 221 /* */
 222 void pkgSimulate::ShortBreaks()
 223 {
 224    cout << " [";
 225    for (PkgIterator I = Sim.PkgBegin(); I.end() == false; ++I)
 226    {
 227       if (Sim[I].InstBroken() == true)
 228       {
 229          if (Flags[I->ID] == 0)
 230             cout << I.FullName(false) << ' ';
 231 /*       else
 232             cout << I.Name() << "! ";*/
 233       }
 234    }
 235    cout << ']' << endl;
 236 }
 237                                                                         /*}}}*/
 238 // ApplyStatus - Adjust for non-ok packages                             /*{{{*/
 239 // ---------------------------------------------------------------------
 240 /* We attempt to change the state of the all packages that have failed
 241    installation toward their real state. The ordering code will perform
 242    the necessary calculations to deal with the problems. */
 243 bool pkgApplyStatus(pkgDepCache &Cache)
 244 {
 245    pkgDepCache::ActionGroup group(Cache);
 246
 247    for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
 248    {
 249       if (I->VersionList == 0)
 250          continue;
 251
 252       // Only choice for a ReInstReq package is to reinstall
 253       if (I->InstState == pkgCache::State::ReInstReq ||
 254           I->InstState == pkgCache::State::HoldReInstReq)
 255       {
 256          if (I->CurrentVer != 0 && I.CurrentVer().Downloadable() == true)
 257             Cache.MarkKeep(I, false, false);
 258          else
 259          {
 260             // Is this right? Will dpkg choke on an upgrade?
 261             if (Cache[I].CandidateVer != 0 &&
 262                  Cache[I].CandidateVerIter(Cache).Downloadable() == true)
 263                Cache.MarkInstall(I, false, 0, false);
 264             else
 265                return _error->Error(_("The package %s needs to be reinstalled, "
 266                                     "but I can't find an archive for it."),I.FullName(true).c_str());
 267          }
 268
 269          continue;
 270       }
 271
 272       switch (I->CurrentState)
 273       {
 274          /* This means installation failed somehow - it does not need to be
 275             re-unpacked (probably) */
 276          case pkgCache::State::UnPacked:
 277          case pkgCache::State::HalfConfigured:
 278          case pkgCache::State::TriggersAwaited:
 279          case pkgCache::State::TriggersPending:
 280          if ((I->CurrentVer != 0 && I.CurrentVer().Downloadable() == true) ||
 281              I.State() != pkgCache::PkgIterator::NeedsUnpack)
 282             Cache.MarkKeep(I, false, false);
 283          else
 284          {
 285             if (Cache[I].CandidateVer != 0 &&
 286                  Cache[I].CandidateVerIter(Cache).Downloadable() == true)
 287                Cache.MarkInstall(I, true, 0, false);
 288             else
 289                Cache.MarkDelete(I, false, 0, false);
 290          }
 291          break;
 292
 293          // This means removal failed
 294          case pkgCache::State::HalfInstalled:
 295          Cache.MarkDelete(I, false, 0, false);
 296          break;
 297
 298          default:
 299          if (I->InstState != pkgCache::State::Ok)
 300             return _error->Error("The package %s is not ok and I "
 301                                  "don't know how to fix it!",I.FullName(false).c_str());
 302       }
 303    }
 304    return true;
 305 }
 306                                                                         /*}}}*/
 307 // FixBroken - Fix broken packages                                      /*{{{*/
 308 // ---------------------------------------------------------------------
 309 /* This autoinstalls every broken package and then runs the problem resolver
 310    on the result. */
 311 bool pkgFixBroken(pkgDepCache &Cache)
 312 {
 313    pkgDepCache::ActionGroup group(Cache);
 314
 315    // Auto upgrade all broken packages
 316    for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
 317       if (Cache[I].NowBroken() == true)
 318          Cache.MarkInstall(I, true, 0, false);
 319
 320    /* Fix packages that are in a NeedArchive state but don't have a
 321       downloadable install version */
 322    for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
 323    {
 324       if (I.State() != pkgCache::PkgIterator::NeedsUnpack ||
 325           Cache[I].Delete() == true)
 326          continue;
 327
 328       if (Cache[I].InstVerIter(Cache).Downloadable() == false)
 329          continue;
 330
 331       Cache.MarkInstall(I, true, 0, false);
 332    }
 333
 334    pkgProblemResolver Fix(&Cache);
 335    return Fix.Resolve(true);
 336 }
 337                                                                         /*}}}*/
 338 // ProblemResolver::pkgProblemResolver - Constructor                    /*{{{*/
 339 // ---------------------------------------------------------------------
 340 /* */
 341 pkgProblemResolver::pkgProblemResolver(pkgDepCache *pCache) : d(NULL), Cache(*pCache)
 342 {
 343    // Allocate memory
 344    unsigned long Size = Cache.Head().PackageCount;
 345    Scores = new int[Size];
 346    Flags = new unsigned char[Size];
 347    memset(Flags,0,sizeof(*Flags)*Size);
 348
 349    // Set debug to true to see its decision logic
 350    Debug = _config->FindB("Debug::pkgProblemResolver",false);
 351 }
 352                                                                         /*}}}*/
 353 // ProblemResolver::~pkgProblemResolver - Destructor                    /*{{{*/
 354 // ---------------------------------------------------------------------
 355 /* */
 356 pkgProblemResolver::~pkgProblemResolver()
 357 {
 358    delete [] Scores;
 359    delete [] Flags;
 360 }
 361                                                                         /*}}}*/
 362 // ProblemResolver::ScoreSort - Sort the list by score                  /*{{{*/
 363 // ---------------------------------------------------------------------
 364 /* */
 365 int pkgProblemResolver::ScoreSort(const void *a,const void *b)
 366 {
 367    Package const **A = (Package const **)a;
 368    Package const **B = (Package const **)b;
 369    if (This->Scores[(*A)->ID] > This->Scores[(*B)->ID])
 370       return -1;
 371    if (This->Scores[(*A)->ID] < This->Scores[(*B)->ID])
 372       return 1;
 373    return 0;
 374 }
 375                                                                         /*}}}*/
 376 // ProblemResolver::MakeScores - Make the score table                   /*{{{*/
 377 // ---------------------------------------------------------------------
 378 /* */
 379 void pkgProblemResolver::MakeScores()
 380 {
 381    unsigned long Size = Cache.Head().PackageCount;
 382    memset(Scores,0,sizeof(*Scores)*Size);
 383
 384    // maps to pkgCache::State::VerPriority:
 385    //    Required Important Standard Optional Extra
 386    int PrioMap[] = {
 387       0,
 388       _config->FindI("pkgProblemResolver::Scores::Required",3),
 389       _config->FindI("pkgProblemResolver::Scores::Important",2),
 390       _config->FindI("pkgProblemResolver::Scores::Standard",1),
 391       _config->FindI("pkgProblemResolver::Scores::Optional",-1),
 392       _config->FindI("pkgProblemResolver::Scores::Extra",-2)
 393    };
 394    int PrioEssentials = _config->FindI("pkgProblemResolver::Scores::Essentials",100);
 395    int PrioInstalledAndNotObsolete = _config->FindI("pkgProblemResolver::Scores::NotObsolete",1);
 396    int DepMap[] = {
 397       0,
 398       _config->FindI("pkgProblemResolver::Scores::Depends",1),
 399       _config->FindI("pkgProblemResolver::Scores::PreDepends",1),
 400       _config->FindI("pkgProblemResolver::Scores::Suggests",0),
 401       _config->FindI("pkgProblemResolver::Scores::Recommends",1),
 402       _config->FindI("pkgProblemResolver::Scores::Conflicts",-1),
 403       _config->FindI("pkgProblemResolver::Scores::Replaces",0),
 404       _config->FindI("pkgProblemResolver::Scores::Obsoletes",0),
 405       _config->FindI("pkgProblemResolver::Scores::Breaks",-1),
 406       _config->FindI("pkgProblemResolver::Scores::Enhances",0)
 407    };
 408    int AddProtected = _config->FindI("pkgProblemResolver::Scores::AddProtected",10000);
 409    int AddEssential = _config->FindI("pkgProblemResolver::Scores::AddEssential",5000);
 410
 411    if (_config->FindB("Debug::pkgProblemResolver::ShowScores",false) == true)
 412       clog << "Settings used to calculate pkgProblemResolver::Scores::" << endl
 413          << "  Required => " << PrioMap[pkgCache::State::Required] << endl
 414          << "  Important => " << PrioMap[pkgCache::State::Important] << endl
 415          << "  Standard => " << PrioMap[pkgCache::State::Standard] << endl
 416          << "  Optional => " << PrioMap[pkgCache::State::Optional] << endl
 417          << "  Extra => " << PrioMap[pkgCache::State::Extra] << endl
 418          << "  Essentials => " << PrioEssentials << endl
 419          << "  InstalledAndNotObsolete => " << PrioInstalledAndNotObsolete << endl
 420          << "  Pre-Depends => " << DepMap[pkgCache::Dep::PreDepends] << endl
 421          << "  Depends => " << DepMap[pkgCache::Dep::Depends] << endl
 422          << "  Recommends => " << DepMap[pkgCache::Dep::Recommends] << endl
 423          << "  Suggests => " << DepMap[pkgCache::Dep::Suggests] << endl
 424          << "  Conflicts => " << DepMap[pkgCache::Dep::Conflicts] << endl
 425          << "  Breaks => " << DepMap[pkgCache::Dep::DpkgBreaks] << endl
 426          << "  Replaces => " << DepMap[pkgCache::Dep::Replaces] << endl
 427          << "  Obsoletes => " << DepMap[pkgCache::Dep::Obsoletes] << endl
 428          << "  Enhances => " << DepMap[pkgCache::Dep::Enhances] << endl
 429          << "  AddProtected => " << AddProtected << endl
 430          << "  AddEssential => " << AddEssential << endl;
 431
 432    // Generate the base scores for a package based on its properties
 433    for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
 434    {
 435       if (Cache[I].InstallVer == 0)
 436          continue;
 437
 438       int &Score = Scores[I->ID];
 439
 440       /* This is arbitrary, it should be high enough to elevate an
 441          essantial package above most other packages but low enough
 442          to allow an obsolete essential packages to be removed by
 443          a conflicts on a powerful normal package (ie libc6) */
 444       if ((I->Flags & pkgCache::Flag::Essential) == pkgCache::Flag::Essential
 445           || (I->Flags & pkgCache::Flag::Important) == pkgCache::Flag::Important)
 446          Score += PrioEssentials;
 447
 448       pkgCache::VerIterator const InstVer = Cache[I].InstVerIter(Cache);
 449       // We apply priorities only to downloadable packages, all others are prio:extra
 450       // as an obsolete prio:standard package can't be that standard anymore…
 451       if (InstVer->Priority <= pkgCache::State::Extra && InstVer.Downloadable() == true)
 452          Score += PrioMap[InstVer->Priority];
 453       else
 454          Score += PrioMap[pkgCache::State::Extra];
 455
 456       /* This helps to fix oddball problems with conflicting packages
 457          on the same level. We enhance the score of installed packages
 458          if those are not obsolete */
 459       if (I->CurrentVer != 0 && Cache[I].CandidateVer != 0 && Cache[I].CandidateVerIter(Cache).Downloadable())
 460          Score += PrioInstalledAndNotObsolete;
 461
 462       // propagate score points along dependencies
 463       for (pkgCache::DepIterator D = InstVer.DependsList(); D.end() == false; ++D)
 464       {
 465          if (DepMap[D->Type] == 0)
 466             continue;
 467          pkgCache::PkgIterator const T = D.TargetPkg();
 468          if (D->Version != 0)
 469          {
 470             pkgCache::VerIterator const IV = Cache[T].InstVerIter(Cache);
 471             if (IV.end() == true || D.IsSatisfied(IV) == false)
 472                continue;
 473          }
 474          Scores[T->ID] += DepMap[D->Type];
 475       }
 476    }
 477
 478    // Copy the scores to advoid additive looping
 479    SPtrArray<int> OldScores = new int[Size];
 480    memcpy(OldScores,Scores,sizeof(*Scores)*Size);
 481
 482    /* Now we cause 1 level of dependency inheritance, that is we add the
 483       score of the packages that depend on the target Package. This
 484       fortifies high scoring packages */
 485    for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
 486    {
 487       if (Cache[I].InstallVer == 0)
 488          continue;
 489
 490       for (pkgCache::DepIterator D = I.RevDependsList(); D.end() == false; ++D)
 491       {
 492          // Only do it for the install version
 493          if ((pkgCache::Version *)D.ParentVer() != Cache[D.ParentPkg()].InstallVer ||
 494              (D->Type != pkgCache::Dep::Depends &&
 495               D->Type != pkgCache::Dep::PreDepends &&
 496               D->Type != pkgCache::Dep::Recommends))
 497             continue;
 498
 499          // Do not propagate negative scores otherwise
 500          // an extra (-2) package might score better than an optional (-1)
 501          if (OldScores[D.ParentPkg()->ID] > 0)
 502              Scores[I->ID] += OldScores[D.ParentPkg()->ID];
 503       }
 504    }
 505
 506    /* Now we propagate along provides. This makes the packages that
 507       provide important packages extremely important */
 508    for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
 509    {
 510       for (pkgCache::PrvIterator P = I.ProvidesList(); P.end() == false; ++P)
 511       {
 512          // Only do it once per package
 513          if ((pkgCache::Version *)P.OwnerVer() != Cache[P.OwnerPkg()].InstallVer)
 514             continue;
 515          Scores[P.OwnerPkg()->ID] += abs(Scores[I->ID] - OldScores[I->ID]);
 516       }
 517    }
 518
 519    /* Protected things are pushed really high up. This number should put them
 520       ahead of everything */
 521    for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
 522    {
 523       if ((Flags[I->ID] & Protected) != 0)
 524          Scores[I->ID] += AddProtected;
 525       if ((I->Flags & pkgCache::Flag::Essential) == pkgCache::Flag::Essential ||
 526           (I->Flags & pkgCache::Flag::Important) == pkgCache::Flag::Important)
 527          Scores[I->ID] += AddEssential;
 528    }
 529 }
 530                                                                         /*}}}*/
 531 // ProblemResolver::DoUpgrade - Attempt to upgrade this package         /*{{{*/
 532 // ---------------------------------------------------------------------
 533 /* This goes through and tries to reinstall packages to make this package
 534    installable */
 535 bool pkgProblemResolver::DoUpgrade(pkgCache::PkgIterator Pkg)
 536 {
 537    pkgDepCache::ActionGroup group(Cache);
 538
 539    if ((Flags[Pkg->ID] & Upgradable) == 0 || Cache[Pkg].Upgradable() == false)
 540       return false;
 541    if ((Flags[Pkg->ID] & Protected) == Protected)
 542       return false;
 543
 544    Flags[Pkg->ID] &= ~Upgradable;
 545
 546    bool WasKept = Cache[Pkg].Keep();
 547    Cache.MarkInstall(Pkg, false, 0, false);
 548
 549    // This must be a virtual package or something like that.
 550    if (Cache[Pkg].InstVerIter(Cache).end() == true)
 551       return false;
 552
 553    // Isolate the problem dependency
 554    bool Fail = false;
 555    for (pkgCache::DepIterator D = Cache[Pkg].InstVerIter(Cache).DependsList(); D.end() == false;)
 556    {
 557       // Compute a single dependency element (glob or)
 558       pkgCache::DepIterator Start = D;
 559       pkgCache::DepIterator End = D;
 560       for (bool LastOR = true; D.end() == false && LastOR == true;)
 561       {
 562          LastOR = (D->CompareOp & pkgCache::Dep::Or) == pkgCache::Dep::Or;
 563          ++D;
 564          if (LastOR == true)
 565             End = D;
 566       }
 567
 568       // We only worry about critical deps.
 569       if (End.IsCritical() != true)
 570          continue;
 571
 572       // Iterate over all the members in the or group
 573       while (1)
 574       {
 575          // Dep is ok now
 576          if ((Cache[End] & pkgDepCache::DepGInstall) == pkgDepCache::DepGInstall)
 577             break;
 578
 579          // Do not change protected packages
 580          PkgIterator P = Start.SmartTargetPkg();
 581          if ((Flags[P->ID] & Protected) == Protected)
 582          {
 583             if (Debug == true)
 584                clog << "    Reinst Failed because of protected " << P.FullName(false) << endl;
 585             Fail = true;
 586          }
 587          else
 588          {
 589             // Upgrade the package if the candidate version will fix the problem.
 590             if ((Cache[Start] & pkgDepCache::DepCVer) == pkgDepCache::DepCVer)
 591             {
 592                if (DoUpgrade(P) == false)
 593                {
 594                   if (Debug == true)
 595                      clog << "    Reinst Failed because of " << P.FullName(false) << endl;
 596                   Fail = true;
 597                }
 598                else
 599                {
 600                   Fail = false;
 601                   break;
 602                }
 603             }
 604             else
 605             {
 606                /* We let the algorithm deal with conflicts on its next iteration,
 607                 it is much smarter than us */
 608                if (Start.IsNegative() == true)
 609                    break;
 610
 611                if (Debug == true)
 612                   clog << "    Reinst Failed early because of " << Start.TargetPkg().FullName(false) << endl;
 613                Fail = true;
 614             }
 615          }
 616
 617          if (Start == End)
 618             break;
 619          ++Start;
 620       }
 621       if (Fail == true)
 622          break;
 623    }
 624
 625    // Undo our operations - it might be smart to undo everything this did..
 626    if (Fail == true)
 627    {
 628       if (WasKept == true)
 629          Cache.MarkKeep(Pkg, false, false);
 630       else
 631          Cache.MarkDelete(Pkg, false, 0, false);
 632       return false;
 633    }
 634
 635    if (Debug == true)
 636       clog << "  Re-Instated " << Pkg.FullName(false) << endl;
 637    return true;
 638 }
 639                                                                         /*}}}*/
 640 // ProblemResolver::Resolve - calls a resolver to fix the situation     /*{{{*/
 641 // ---------------------------------------------------------------------
 642 /* */
 643 bool pkgProblemResolver::Resolve(bool BrokenFix)
 644 {
 645    std::string const solver = _config->Find("APT::Solver", "internal");
 646    if (solver != "internal") {
 647       OpTextProgress Prog(*_config);
 648       return EDSP::ResolveExternal(solver.c_str(), Cache, false, false, false, &Prog);
 649    }
 650    return ResolveInternal(BrokenFix);
 651 }
 652                                                                         /*}}}*/
 653 // ProblemResolver::ResolveInternal - Run the resolution pass           /*{{{*/
 654 // ---------------------------------------------------------------------
 655 /* This routines works by calculating a score for each package. The score
 656    is derived by considering the package's priority and all reverse
 657    dependents giving an integer that reflects the amount of breakage that
 658    adjusting the package will inflict.
 659
 660    It goes from highest score to lowest and corrects all of the breaks by
 661    keeping or removing the dependent packages. If that fails then it removes
 662    the package itself and goes on. The routine should be able to intelligently
 663    go from any broken state to a fixed state.
 664
 665    The BrokenFix flag enables a mode where the algorithm tries to
 666    upgrade packages to advoid problems. */
 667 bool pkgProblemResolver::ResolveInternal(bool const BrokenFix)
 668 {
 669    pkgDepCache::ActionGroup group(Cache);
 670
 671    // Record which packages are marked for install
 672    bool Again = false;
 673    do
 674    {
 675       Again = false;
 676       for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
 677       {
 678          if (Cache[I].Install() == true)
 679             Flags[I->ID] |= PreInstalled;
 680          else
 681          {
 682             if (Cache[I].InstBroken() == true && BrokenFix == true)
 683             {
 684                Cache.MarkInstall(I, false, 0, false);
 685                if (Cache[I].Install() == true)
 686                   Again = true;
 687             }
 688
 689             Flags[I->ID] &= ~PreInstalled;
 690          }
 691          Flags[I->ID] |= Upgradable;
 692       }
 693    }
 694    while (Again == true);
 695
 696    if (Debug == true) {
 697       clog << "Starting pkgProblemResolver with broken count: "
 698            << Cache.BrokenCount() << endl;
 699    }
 700
 701    MakeScores();
 702
 703    unsigned long const Size = Cache.Head().PackageCount;
 704
 705    /* We have to order the packages so that the broken fixing pass
 706       operates from highest score to lowest. This prevents problems when
 707       high score packages cause the removal of lower score packages that
 708       would cause the removal of even lower score packages. */
 709    SPtrArray<pkgCache::Package *> PList = new pkgCache::Package *[Size];
 710    pkgCache::Package **PEnd = PList;
 711    for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
 712       *PEnd++ = I;
 713    This = this;
 714    qsort(PList,PEnd - PList,sizeof(*PList),&ScoreSort);
 715
 716    if (_config->FindB("Debug::pkgProblemResolver::ShowScores",false) == true)
 717    {
 718       clog << "Show Scores" << endl;
 719       for (pkgCache::Package **K = PList; K != PEnd; K++)
 720          if (Scores[(*K)->ID] != 0)
 721          {
 722            pkgCache::PkgIterator Pkg(Cache,*K);
 723            clog << Scores[(*K)->ID] << ' ' << Pkg << std::endl;
 724          }
 725    }
 726
 727    if (Debug == true) {
 728       clog << "Starting 2 pkgProblemResolver with broken count: "
 729            << Cache.BrokenCount() << endl;
 730    }
 731
 732    /* Now consider all broken packages. For each broken package we either
 733       remove the package or fix it's problem. We do this once, it should
 734       not be possible for a loop to form (that is a < b < c and fixing b by
 735       changing a breaks c) */
 736    bool Change = true;
 737    bool const TryFixByInstall = _config->FindB("pkgProblemResolver::FixByInstall", true);
 738    for (int Counter = 0; Counter != 10 && Change == true; Counter++)
 739    {
 740       Change = false;
 741       for (pkgCache::Package **K = PList; K != PEnd; K++)
 742       {
 743          pkgCache::PkgIterator I(Cache,*K);
 744
 745          /* We attempt to install this and see if any breaks result,
 746             this takes care of some strange cases */
 747          if (Cache[I].CandidateVer != Cache[I].InstallVer &&
 748              I->CurrentVer != 0 && Cache[I].InstallVer != 0 &&
 749              (Flags[I->ID] & PreInstalled) != 0 &&
 750              (Flags[I->ID] & Protected) == 0 &&
 751              (Flags[I->ID] & ReInstateTried) == 0)
 752          {
 753             if (Debug == true)
 754                clog << " Try to Re-Instate (" << Counter << ") " << I.FullName(false) << endl;
 755             unsigned long OldBreaks = Cache.BrokenCount();
 756             pkgCache::Version *OldVer = Cache[I].InstallVer;
 757             Flags[I->ID] &= ReInstateTried;
 758
 759             Cache.MarkInstall(I, false, 0, false);
 760             if (Cache[I].InstBroken() == true ||
 761                 OldBreaks < Cache.BrokenCount())
 762             {
 763                if (OldVer == 0)
 764                   Cache.MarkDelete(I, false, 0, false);
 765                else
 766                   Cache.MarkKeep(I, false, false);
 767             }
 768             else
 769                if (Debug == true)
 770                   clog << "Re-Instated " << I.FullName(false) << " (" << OldBreaks << " vs " << Cache.BrokenCount() << ')' << endl;
 771          }
 772
 773          if (Cache[I].InstallVer == 0 || Cache[I].InstBroken() == false)
 774             continue;
 775
 776          if (Debug == true)
 777             clog << "Investigating (" << Counter << ") " << I << endl;
 778
 779          // Isolate the problem dependency
 780          PackageKill KillList[100];
 781          PackageKill *LEnd = KillList;
 782          bool InOr = false;
 783          pkgCache::DepIterator Start;
 784          pkgCache::DepIterator End;
 785          PackageKill *OldEnd = LEnd;
 786
 787          enum {OrRemove,OrKeep} OrOp = OrRemove;
 788          for (pkgCache::DepIterator D = Cache[I].InstVerIter(Cache).DependsList();
 789               D.end() == false || InOr == true;)
 790          {
 791             // Compute a single dependency element (glob or)
 792             if (Start == End)
 793             {
 794                // Decide what to do
 795                if (InOr == true && OldEnd == LEnd)
 796                {
 797                   if (OrOp == OrRemove)
 798                   {
 799                      if ((Flags[I->ID] & Protected) != Protected)
 800                      {
 801                         if (Debug == true)
 802                            clog << "  Or group remove for " << I.FullName(false) << endl;
 803                         Cache.MarkDelete(I, false, 0, false);
 804                         Change = true;
 805                      }
 806                   }
 807                   else if (OrOp == OrKeep)
 808                   {
 809                      if (Debug == true)
 810                         clog << "  Or group keep for " << I.FullName(false) << endl;
 811                      Cache.MarkKeep(I, false, false);
 812                      Change = true;
 813                   }
 814                }
 815
 816                /* We do an extra loop (as above) to finalize the or group
 817                   processing */
 818                InOr = false;
 819                OrOp = OrRemove;
 820                D.GlobOr(Start,End);
 821                if (Start.end() == true)
 822                   break;
 823
 824                // We only worry about critical deps.
 825                if (End.IsCritical() != true)
 826                   continue;
 827
 828                InOr = Start != End;
 829                OldEnd = LEnd;
 830             }
 831             else
 832             {
 833                ++Start;
 834                // We only worry about critical deps.
 835                if (Start.IsCritical() != true)
 836                   continue;
 837             }
 838
 839             // Dep is ok
 840             if ((Cache[End] & pkgDepCache::DepGInstall) == pkgDepCache::DepGInstall)
 841             {
 842                InOr = false;
 843                continue;
 844             }
 845
 846             if (Debug == true)
 847                clog << "Broken " << Start << endl;
 848
 849             /* Look across the version list. If there are no possible
 850                targets then we keep the package and bail. This is necessary
 851                if a package has a dep on another package that can't be found */
 852             SPtrArray<pkgCache::Version *> VList = Start.AllTargets();
 853             if (*VList == 0 && (Flags[I->ID] & Protected) != Protected &&
 854                 Start.IsNegative() == false &&
 855                 Cache[I].NowBroken() == false)
 856             {
 857                if (InOr == true)
 858                {
 859                   /* No keep choice because the keep being OK could be the
 860                      result of another element in the OR group! */
 861                   continue;
 862                }
 863
 864                Change = true;
 865                Cache.MarkKeep(I, false, false);
 866                break;
 867             }
 868
 869             bool Done = false;
 870             for (pkgCache::Version **V = VList; *V != 0; V++)
 871             {
 872                pkgCache::VerIterator Ver(Cache,*V);
 873                pkgCache::PkgIterator Pkg = Ver.ParentPkg();
 874
 875                /* This is a conflicts, and the version we are looking
 876                   at is not the currently selected version of the
 877                   package, which means it is not necessary to
 878                   remove/keep */
 879                if (Cache[Pkg].InstallVer != Ver && Start.IsNegative() == true)
 880                {
 881                   if (Debug)
 882                      clog << "  Conflicts//Breaks against version "
 883                           << Ver.VerStr() << " for " << Pkg.Name()
 884                           << " but that is not InstVer, ignoring"
 885                           << endl;
 886                   continue;
 887                }
 888
 889                if (Debug == true)
 890                   clog << "  Considering " << Pkg.FullName(false) << ' ' << Scores[Pkg->ID] <<
 891                   " as a solution to " << I.FullName(false) << ' ' << Scores[I->ID] << endl;
 892
 893                /* Try to fix the package under consideration rather than
 894                   fiddle with the VList package */
 895                if (Scores[I->ID] <= Scores[Pkg->ID] ||
 896                    ((Cache[Start] & pkgDepCache::DepNow) == 0 &&
 897                     End.IsNegative() == false))
 898                {
 899                   // Try a little harder to fix protected packages..
 900                   if ((Flags[I->ID] & Protected) == Protected)
 901                   {
 902                      if (DoUpgrade(Pkg) == true)
 903                      {
 904                         if (Scores[Pkg->ID] > Scores[I->ID])
 905                            Scores[Pkg->ID] = Scores[I->ID];
 906                         break;
 907                      }
 908
 909                      continue;
 910                   }
 911
 912                   /* See if a keep will do, unless the package is protected,
 913                      then installing it will be necessary */
 914                   bool Installed = Cache[I].Install();
 915                   Cache.MarkKeep(I, false, false);
 916                   if (Cache[I].InstBroken() == false)
 917                   {
 918                      // Unwind operation will be keep now
 919                      if (OrOp == OrRemove)
 920                         OrOp = OrKeep;
 921
 922                      // Restore
 923                      if (InOr == true && Installed == true)
 924                         Cache.MarkInstall(I, false, 0, false);
 925
 926                      if (Debug == true)
 927                         clog << "  Holding Back " << I.FullName(false) << " rather than change " << Start.TargetPkg().FullName(false) << endl;
 928                   }
 929                   else
 930                   {
 931                      if (BrokenFix == false || DoUpgrade(I) == false)
 932                      {
 933                         // Consider other options
 934                         if (InOr == false || Cache[I].Garbage == true)
 935                         {
 936                            if (Debug == true)
 937                               clog << "  Removing " << I.FullName(false) << " rather than change " << Start.TargetPkg().FullName(false) << endl;
 938                            Cache.MarkDelete(I, false, 0, false);
 939                            if (Counter > 1 && Scores[Pkg->ID] > Scores[I->ID])
 940                               Scores[I->ID] = Scores[Pkg->ID];
 941                         }
 942                         else if (TryFixByInstall == true &&
 943                                  Start.TargetPkg()->CurrentVer == 0 &&
 944                                  Cache[Start.TargetPkg()].Delete() == false &&
 945                                  (Flags[Start.TargetPkg()->ID] & ToRemove) != ToRemove &&
 946                                  Cache.GetCandidateVer(Start.TargetPkg()).end() == false)
 947                         {
 948                            /* Before removing or keeping the package with the broken dependency
 949                               try instead to install the first not previously installed package
 950                               solving this dependency. This helps every time a previous solver
 951                               is removed by the resolver because of a conflict or alike but it is
 952                               dangerous as it could trigger new breaks/conflicts… */
 953                            if (Debug == true)
 954                               clog << "  Try Installing " << Start.TargetPkg() << " before changing " << I.FullName(false) << std::endl;
 955                            unsigned long const OldBroken = Cache.BrokenCount();
 956                            Cache.MarkInstall(Start.TargetPkg(), true, 1, false);
 957                            // FIXME: we should undo the complete MarkInstall process here
 958                            if (Cache[Start.TargetPkg()].InstBroken() == true || Cache.BrokenCount() > OldBroken)
 959                               Cache.MarkDelete(Start.TargetPkg(), false, 1, false);
 960                         }
 961                      }
 962                   }
 963
 964                   Change = true;
 965                   Done = true;
 966                   break;
 967                }
 968                else
 969                {
 970                   if (Start->Type == pkgCache::Dep::DpkgBreaks)
 971                   {
 972                      // first, try upgradring the package, if that
 973                      // does not help, the breaks goes onto the
 974                      // kill list
 975                      //
 976                      // FIXME: use DoUpgrade(Pkg) instead?
 977                      if (Cache[End] & pkgDepCache::DepGCVer)
 978                      {
 979                         if (Debug)
 980                            clog << "  Upgrading " << Pkg.FullName(false) << " due to Breaks field in " << I.FullName(false) << endl;
 981                         Cache.MarkInstall(Pkg, false, 0, false);
 982                         continue;
 983                      }
 984                   }
 985
 986                   // Skip adding to the kill list if it is protected
 987                   if ((Flags[Pkg->ID] & Protected) != 0)
 988                      continue;
 989
 990                   if (Debug == true)
 991                      clog << "  Added " << Pkg.FullName(false) << " to the remove list" << endl;
 992
 993                   LEnd->Pkg = Pkg;
 994                   LEnd->Dep = End;
 995                   LEnd++;
 996
 997                   if (Start.IsNegative() == false)
 998                      break;
 999                }
1000             }
1001
1002             // Hm, nothing can possibly satisify this dep. Nuke it.
1003             if (VList[0] == 0 &&
1004                 Start.IsNegative() == false &&
1005                 (Flags[I->ID] & Protected) != Protected)
1006             {
1007                bool Installed = Cache[I].Install();
1008                Cache.MarkKeep(I);
1009                if (Cache[I].InstBroken() == false)
1010                {
1011                   // Unwind operation will be keep now
1012                   if (OrOp == OrRemove)
1013                      OrOp = OrKeep;
1014
1015                   // Restore
1016                   if (InOr == true && Installed == true)
1017                      Cache.MarkInstall(I, false, 0, false);
1018
1019                   if (Debug == true)
1020                      clog << "  Holding Back " << I.FullName(false) << " because I can't find " << Start.TargetPkg().FullName(false) << endl;
1021                }
1022                else
1023                {
1024                   if (Debug == true)
1025                      clog << "  Removing " << I.FullName(false) << " because I can't find " << Start.TargetPkg().FullName(false) << endl;
1026                   if (InOr == false)
1027                      Cache.MarkDelete(I, false, 0, false);
1028                }
1029
1030                Change = true;
1031                Done = true;
1032             }
1033
1034             // Try some more
1035             if (InOr == true)
1036                continue;
1037
1038             if (Done == true)
1039                break;
1040          }
1041
1042          // Apply the kill list now
1043          if (Cache[I].InstallVer != 0)
1044          {
1045             for (PackageKill *J = KillList; J != LEnd; J++)
1046             {
1047                Change = true;
1048                if ((Cache[J->Dep] & pkgDepCache::DepGNow) == 0)
1049                {
1050                   if (J->Dep.IsNegative() == true)
1051                   {
1052                      if (Debug == true)
1053                         clog << "  Fixing " << I.FullName(false) << " via remove of " << J->Pkg.FullName(false) << endl;
1054                      Cache.MarkDelete(J->Pkg, false, 0, false);
1055                   }
1056                }
1057                else
1058                {
1059                   if (Debug == true)
1060                      clog << "  Fixing " << I.FullName(false) << " via keep of " << J->Pkg.FullName(false) << endl;
1061                   Cache.MarkKeep(J->Pkg, false, false);
1062                }
1063
1064                if (Counter > 1)
1065                {
1066                   if (Scores[I->ID] > Scores[J->Pkg->ID])
1067                      Scores[J->Pkg->ID] = Scores[I->ID];
1068                }
1069             }
1070          }
1071       }
1072    }
1073
1074    if (Debug == true)
1075       clog << "Done" << endl;
1076
1077    if (Cache.BrokenCount() != 0)
1078    {
1079       // See if this is the result of a hold
1080       pkgCache::PkgIterator I = Cache.PkgBegin();
1081       for (;I.end() != true; ++I)
1082       {
1083          if (Cache[I].InstBroken() == false)
1084             continue;
1085          if ((Flags[I->ID] & Protected) != Protected)
1086             return _error->Error(_("Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages."));
1087       }
1088       return _error->Error(_("Unable to correct problems, you have held broken packages."));
1089    }
1090
1091    // set the auto-flags (mvo: I'm not sure if we _really_ need this)
1092    pkgCache::PkgIterator I = Cache.PkgBegin();
1093    for (;I.end() != true; ++I) {
1094       if (Cache[I].NewInstall() && !(Flags[I->ID] & PreInstalled)) {
1095          if(_config->FindI("Debug::pkgAutoRemove",false)) {
1096             std::clog << "Resolve installed new pkg: " << I.FullName(false)
1097                       << " (now marking it as auto)" << std::endl;
1098          }
1099          Cache[I].Flags |= pkgCache::Flag::Auto;
1100       }
1101    }
1102
1103
1104    return true;
1105 }
1106                                                                         /*}}}*/
1107 // ProblemResolver::BreaksInstOrPolicy - Check if the given pkg is broken/*{{{*/
1108 // ---------------------------------------------------------------------
1109 /* This checks if the given package is broken either by a hard dependency
1110    (InstBroken()) or by introducing a new policy breakage e.g. new
1111    unsatisfied recommends for a package that was in "policy-good" state
1112
1113    Note that this is not perfect as it will ignore further breakage
1114    for already broken policy (recommends)
1115 */
1116 bool pkgProblemResolver::InstOrNewPolicyBroken(pkgCache::PkgIterator I)
1117 {
1118    // a broken install is always a problem
1119    if (Cache[I].InstBroken() == true)
1120    {
1121       if (Debug == true)
1122          std::clog << "  Dependencies are not satisfied for " << I << std::endl;
1123       return true;
1124    }
1125
1126    // a newly broken policy (recommends/suggests) is a problem
1127    if (Cache[I].NowPolicyBroken() == false &&
1128        Cache[I].InstPolicyBroken() == true)
1129    {
1130       if (Debug == true)
1131          std::clog << "  Policy breaks with upgrade of " << I << std::endl;
1132       return true;
1133    }
1134
1135    return false;
1136 }
1137                                                                         /*}}}*/
1138 // ProblemResolver::ResolveByKeep - Resolve problems using keep         /*{{{*/
1139 // ---------------------------------------------------------------------
1140 /* This is the work horse of the soft upgrade routine. It is very gental
1141    in that it does not install or remove any packages. It is assumed that the
1142    system was non-broken previously. */
1143 bool pkgProblemResolver::ResolveByKeep()
1144 {
1145    std::string const solver = _config->Find("APT::Solver", "internal");
1146    if (solver != "internal") {
1147       OpTextProgress Prog(*_config);
1148       return EDSP::ResolveExternal(solver.c_str(), Cache, true, false, false, &Prog);
1149    }
1150    return ResolveByKeepInternal();
1151 }
1152                                                                         /*}}}*/
1153 // ProblemResolver::ResolveByKeepInternal - Resolve problems using keep /*{{{*/
1154 // ---------------------------------------------------------------------
1155 /* This is the work horse of the soft upgrade routine. It is very gental
1156    in that it does not install or remove any packages. It is assumed that the
1157    system was non-broken previously. */
1158 bool pkgProblemResolver::ResolveByKeepInternal()
1159 {
1160    pkgDepCache::ActionGroup group(Cache);
1161
1162    unsigned long Size = Cache.Head().PackageCount;
1163
1164    MakeScores();
1165
1166    /* We have to order the packages so that the broken fixing pass
1167       operates from highest score to lowest. This prevents problems when
1168       high score packages cause the removal of lower score packages that
1169       would cause the removal of even lower score packages. */
1170    pkgCache::Package **PList = new pkgCache::Package *[Size];
1171    pkgCache::Package **PEnd = PList;
1172    for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
1173       *PEnd++ = I;
1174    This = this;
1175    qsort(PList,PEnd - PList,sizeof(*PList),&ScoreSort);
1176
1177    if (_config->FindB("Debug::pkgProblemResolver::ShowScores",false) == true)
1178    {
1179       clog << "Show Scores" << endl;
1180       for (pkgCache::Package **K = PList; K != PEnd; K++)
1181          if (Scores[(*K)->ID] != 0)
1182          {
1183            pkgCache::PkgIterator Pkg(Cache,*K);
1184            clog << Scores[(*K)->ID] << ' ' << Pkg << std::endl;
1185          }
1186    }
1187
1188    if (Debug == true)
1189       clog << "Entering ResolveByKeep" << endl;
1190
1191    // Consider each broken package
1192    pkgCache::Package **LastStop = 0;
1193    for (pkgCache::Package **K = PList; K != PEnd; K++)
1194    {
1195       pkgCache::PkgIterator I(Cache,*K);
1196
1197       if (Cache[I].InstallVer == 0)
1198          continue;
1199
1200       if (InstOrNewPolicyBroken(I) == false)
1201          continue;
1202
1203       /* Keep the package. If this works then great, otherwise we have
1204          to be significantly more aggressive and manipulate its dependencies */
1205       if ((Flags[I->ID] & Protected) == 0)
1206       {
1207          if (Debug == true)
1208             clog << "Keeping package " << I.FullName(false) << endl;
1209          Cache.MarkKeep(I, false, false);
1210          if (InstOrNewPolicyBroken(I) == false)
1211          {
1212             K = PList - 1;
1213             continue;
1214          }
1215       }
1216
1217       // Isolate the problem dependencies
1218       for (pkgCache::DepIterator D = Cache[I].InstVerIter(Cache).DependsList(); D.end() == false;)
1219       {
1220          DepIterator Start;
1221          DepIterator End;
1222          D.GlobOr(Start,End);
1223
1224          // We only worry about critical deps.
1225          if (End.IsCritical() != true)
1226             continue;
1227
1228          // Dep is ok
1229          if ((Cache[End] & pkgDepCache::DepGInstall) == pkgDepCache::DepGInstall)
1230             continue;
1231
1232          /* Hm, the group is broken.. I suppose the best thing to do is to
1233             is to try every combination of keep/not-keep for the set, but thats
1234             slow, and this never happens, just be conservative and assume the
1235             list of ors is in preference and keep till it starts to work. */
1236          while (true)
1237          {
1238             if (Debug == true)
1239                clog << "Package " << I.FullName(false) << " " << Start << endl;
1240
1241             // Look at all the possible provides on this package
1242             SPtrArray<pkgCache::Version *> VList = Start.AllTargets();
1243             for (pkgCache::Version **V = VList; *V != 0; V++)
1244             {
1245                pkgCache::VerIterator Ver(Cache,*V);
1246                pkgCache::PkgIterator Pkg = Ver.ParentPkg();
1247
1248                // It is not keepable
1249                if (Cache[Pkg].InstallVer == 0 ||
1250                    Pkg->CurrentVer == 0)
1251                   continue;
1252
1253                if ((Flags[I->ID] & Protected) == 0)
1254                {
1255                   if (Debug == true)
1256                      clog << "  Keeping Package " << Pkg.FullName(false) << " due to " << Start.DepType() << endl;
1257                   Cache.MarkKeep(Pkg, false, false);
1258                }
1259
1260                if (InstOrNewPolicyBroken(I) == false)
1261                   break;
1262             }
1263
1264             if (InstOrNewPolicyBroken(I) == false)
1265                break;
1266
1267             if (Start == End)
1268                break;
1269             ++Start;
1270          }
1271
1272          if (InstOrNewPolicyBroken(I) == false)
1273             break;
1274       }
1275
1276       if (InstOrNewPolicyBroken(I) == true)
1277          continue;
1278
1279       // Restart again.
1280       if (K == LastStop) {
1281           // I is an iterator based off our temporary package list,
1282           // so copy the name we need before deleting the temporary list
1283           std::string const LoopingPackage = I.FullName(false);
1284           delete[] PList;
1285           return _error->Error("Internal Error, pkgProblemResolver::ResolveByKeep is looping on package %s.", LoopingPackage.c_str());
1286       }
1287       LastStop = K;
1288       K = PList - 1;
1289    }
1290
1291    delete[] PList;
1292    return true;
1293 }
1294                                                                         /*}}}*/
1295 // ProblemResolver::InstallProtect - deprecated cpu-eating no-op        /*{{{*/
1296 // ---------------------------------------------------------------------
1297 /* Actions issued with FromUser bit set are protected from further
1298    modification (expect by other calls with FromUser set) nowadays , so we
1299    don't need to reissue actions here, they are already set in stone. */
1300 void pkgProblemResolver::InstallProtect()
1301 {
1302    pkgDepCache::ActionGroup group(Cache);
1303
1304    for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
1305    {
1306       if ((Flags[I->ID] & Protected) == Protected)
1307       {
1308          if ((Flags[I->ID] & ToRemove) == ToRemove)
1309             Cache.MarkDelete(I);
1310          else
1311          {
1312             // preserve the information whether the package was auto
1313             // or manually installed
1314             bool autoInst = (Cache[I].Flags & pkgCache::Flag::Auto);
1315             Cache.MarkInstall(I, false, 0, !autoInst);
1316          }
1317       }
1318    }
1319 }
1320                                                                         /*}}}*/
1321 // PrioSortList - Sort a list of versions by priority                   /*{{{*/
1322 // ---------------------------------------------------------------------
1323 /* This is ment to be used in conjunction with AllTargets to get a list
1324    of versions ordered by preference. */
1325 static pkgCache *PrioCache;
1326 static int PrioComp(const void *A,const void *B)
1327 {
1328    pkgCache::VerIterator L(*PrioCache,*(pkgCache::Version **)A);
1329    pkgCache::VerIterator R(*PrioCache,*(pkgCache::Version **)B);
1330
1331    if ((L.ParentPkg()->Flags & pkgCache::Flag::Essential) == pkgCache::Flag::Essential &&
1332        (R.ParentPkg()->Flags & pkgCache::Flag::Essential) != pkgCache::Flag::Essential)
1333      return 1;
1334    if ((L.ParentPkg()->Flags & pkgCache::Flag::Essential) != pkgCache::Flag::Essential &&
1335        (R.ParentPkg()->Flags & pkgCache::Flag::Essential) == pkgCache::Flag::Essential)
1336      return -1;
1337
1338    if ((L.ParentPkg()->Flags & pkgCache::Flag::Important) == pkgCache::Flag::Important &&
1339        (R.ParentPkg()->Flags & pkgCache::Flag::Important) != pkgCache::Flag::Important)
1340      return 1;
1341    if ((L.ParentPkg()->Flags & pkgCache::Flag::Important) != pkgCache::Flag::Important &&
1342        (R.ParentPkg()->Flags & pkgCache::Flag::Important) == pkgCache::Flag::Important)
1343      return -1;
1344
1345    if (L->Priority != R->Priority)
1346       return R->Priority - L->Priority;
1347    return strcmp(L.ParentPkg().Name(),R.ParentPkg().Name());
1348 }
1349 void pkgPrioSortList(pkgCache &Cache,pkgCache::Version **List)
1350 {
1351    unsigned long Count = 0;
1352    PrioCache = &Cache;
1353    for (pkgCache::Version **I = List; *I != 0; I++)
1354       Count++;
1355    qsort(List,Count,sizeof(*List),PrioComp);
1356 }
1357                                                                         /*}}}*/