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  43 /* The legacy translations here of input Pkg iterators is obsolete,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) != D.IsNegative())
 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, OpProgress * const Progress)
 644 {
 645    std::string const solver = _config->Find("APT::Solver", "internal");
 646    if (solver != "internal")
 647       return EDSP::ResolveExternal(solver.c_str(), Cache, false, false, false, Progress);
 648    return ResolveInternal(BrokenFix);
 649 }
 650                                                                         /*}}}*/
 651 // ProblemResolver::ResolveInternal - Run the resolution pass           /*{{{*/
 652 // ---------------------------------------------------------------------
 653 /* This routines works by calculating a score for each package. The score
 654    is derived by considering the package's priority and all reverse
 655    dependents giving an integer that reflects the amount of breakage that
 656    adjusting the package will inflict.
 657
 658    It goes from highest score to lowest and corrects all of the breaks by
 659    keeping or removing the dependent packages. If that fails then it removes
 660    the package itself and goes on. The routine should be able to intelligently
 661    go from any broken state to a fixed state.
 662
 663    The BrokenFix flag enables a mode where the algorithm tries to
 664    upgrade packages to advoid problems. */
 665 bool pkgProblemResolver::ResolveInternal(bool const BrokenFix)
 666 {
 667    pkgDepCache::ActionGroup group(Cache);
 668
 669    // Record which packages are marked for install
 670    bool Again = false;
 671    do
 672    {
 673       Again = false;
 674       for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
 675       {
 676          if (Cache[I].Install() == true)
 677             Flags[I->ID] |= PreInstalled;
 678          else
 679          {
 680             if (Cache[I].InstBroken() == true && BrokenFix == true)
 681             {
 682                Cache.MarkInstall(I, false, 0, false);
 683                if (Cache[I].Install() == true)
 684                   Again = true;
 685             }
 686
 687             Flags[I->ID] &= ~PreInstalled;
 688          }
 689          Flags[I->ID] |= Upgradable;
 690       }
 691    }
 692    while (Again == true);
 693
 694    if (Debug == true) {
 695       clog << "Starting pkgProblemResolver with broken count: "
 696            << Cache.BrokenCount() << endl;
 697    }
 698
 699    MakeScores();
 700
 701    unsigned long const Size = Cache.Head().PackageCount;
 702
 703    /* We have to order the packages so that the broken fixing pass
 704       operates from highest score to lowest. This prevents problems when
 705       high score packages cause the removal of lower score packages that
 706       would cause the removal of even lower score packages. */
 707    SPtrArray<pkgCache::Package *> PList = new pkgCache::Package *[Size];
 708    pkgCache::Package **PEnd = PList;
 709    for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
 710       *PEnd++ = I;
 711    This = this;
 712    qsort(PList,PEnd - PList,sizeof(*PList),&ScoreSort);
 713
 714    if (_config->FindB("Debug::pkgProblemResolver::ShowScores",false) == true)
 715    {
 716       clog << "Show Scores" << endl;
 717       for (pkgCache::Package **K = PList; K != PEnd; K++)
 718          if (Scores[(*K)->ID] != 0)
 719          {
 720            pkgCache::PkgIterator Pkg(Cache,*K);
 721            clog << Scores[(*K)->ID] << ' ' << Pkg << std::endl;
 722          }
 723    }
 724
 725    if (Debug == true) {
 726       clog << "Starting 2 pkgProblemResolver with broken count: "
 727            << Cache.BrokenCount() << endl;
 728    }
 729
 730    /* Now consider all broken packages. For each broken package we either
 731       remove the package or fix it's problem. We do this once, it should
 732       not be possible for a loop to form (that is a < b < c and fixing b by
 733       changing a breaks c) */
 734    bool Change = true;
 735    bool const TryFixByInstall = _config->FindB("pkgProblemResolver::FixByInstall", true);
 736    for (int Counter = 0; Counter != 10 && Change == true; Counter++)
 737    {
 738       Change = false;
 739       for (pkgCache::Package **K = PList; K != PEnd; K++)
 740       {
 741          pkgCache::PkgIterator I(Cache,*K);
 742
 743          /* We attempt to install this and see if any breaks result,
 744             this takes care of some strange cases */
 745          if (Cache[I].CandidateVer != Cache[I].InstallVer &&
 746              I->CurrentVer != 0 && Cache[I].InstallVer != 0 &&
 747              (Flags[I->ID] & PreInstalled) != 0 &&
 748              (Flags[I->ID] & Protected) == 0 &&
 749              (Flags[I->ID] & ReInstateTried) == 0)
 750          {
 751             if (Debug == true)
 752                clog << " Try to Re-Instate (" << Counter << ") " << I.FullName(false) << endl;
 753             unsigned long OldBreaks = Cache.BrokenCount();
 754             pkgCache::Version *OldVer = Cache[I].InstallVer;
 755             Flags[I->ID] &= ReInstateTried;
 756
 757             Cache.MarkInstall(I, false, 0, false);
 758             if (Cache[I].InstBroken() == true ||
 759                 OldBreaks < Cache.BrokenCount())
 760             {
 761                if (OldVer == 0)
 762                   Cache.MarkDelete(I, false, 0, false);
 763                else
 764                   Cache.MarkKeep(I, false, false);
 765             }
 766             else
 767                if (Debug == true)
 768                   clog << "Re-Instated " << I.FullName(false) << " (" << OldBreaks << " vs " << Cache.BrokenCount() << ')' << endl;
 769          }
 770
 771          if (Cache[I].InstallVer == 0 || Cache[I].InstBroken() == false)
 772             continue;
 773
 774          if (Debug == true)
 775             clog << "Investigating (" << Counter << ") " << I << endl;
 776
 777          // Isolate the problem dependency
 778          PackageKill KillList[100];
 779          PackageKill *LEnd = KillList;
 780          bool InOr = false;
 781          pkgCache::DepIterator Start;
 782          pkgCache::DepIterator End;
 783          PackageKill *OldEnd = LEnd;
 784
 785          enum {OrRemove,OrKeep} OrOp = OrRemove;
 786          for (pkgCache::DepIterator D = Cache[I].InstVerIter(Cache).DependsList();
 787               D.end() == false || InOr == true;)
 788          {
 789             // Compute a single dependency element (glob or)
 790             if (Start == End)
 791             {
 792                // Decide what to do
 793                if (InOr == true && OldEnd == LEnd)
 794                {
 795                   if (OrOp == OrRemove)
 796                   {
 797                      if ((Flags[I->ID] & Protected) != Protected)
 798                      {
 799                         if (Debug == true)
 800                            clog << "  Or group remove for " << I.FullName(false) << endl;
 801                         Cache.MarkDelete(I, false, 0, false);
 802                         Change = true;
 803                      }
 804                   }
 805                   else if (OrOp == OrKeep)
 806                   {
 807                      if (Debug == true)
 808                         clog << "  Or group keep for " << I.FullName(false) << endl;
 809                      Cache.MarkKeep(I, false, false);
 810                      Change = true;
 811                   }
 812                }
 813
 814                /* We do an extra loop (as above) to finalize the or group
 815                   processing */
 816                InOr = false;
 817                OrOp = OrRemove;
 818                D.GlobOr(Start,End);
 819                if (Start.end() == true)
 820                   break;
 821
 822                // We only worry about critical deps.
 823                if (End.IsCritical() != true)
 824                   continue;
 825
 826                InOr = Start != End;
 827                OldEnd = LEnd;
 828             }
 829             else
 830             {
 831                ++Start;
 832                // We only worry about critical deps.
 833                if (Start.IsCritical() != true)
 834                   continue;
 835             }
 836
 837             // Dep is ok
 838             if ((Cache[End] & pkgDepCache::DepGInstall) == pkgDepCache::DepGInstall)
 839             {
 840                InOr = false;
 841                continue;
 842             }
 843
 844             if (Debug == true)
 845                clog << "Broken " << Start << endl;
 846
 847             /* Look across the version list. If there are no possible
 848                targets then we keep the package and bail. This is necessary
 849                if a package has a dep on another package that can't be found */
 850             SPtrArray<pkgCache::Version *> VList = Start.AllTargets();
 851             if (*VList == 0 && (Flags[I->ID] & Protected) != Protected &&
 852                 Start.IsNegative() == false &&
 853                 Cache[I].NowBroken() == false)
 854             {
 855                if (InOr == true)
 856                {
 857                   /* No keep choice because the keep being OK could be the
 858                      result of another element in the OR group! */
 859                   continue;
 860                }
 861
 862                Change = true;
 863                Cache.MarkKeep(I, false, false);
 864                break;
 865             }
 866
 867             bool Done = false;
 868             for (pkgCache::Version **V = VList; *V != 0; V++)
 869             {
 870                pkgCache::VerIterator Ver(Cache,*V);
 871                pkgCache::PkgIterator Pkg = Ver.ParentPkg();
 872
 873                /* This is a conflicts, and the version we are looking
 874                   at is not the currently selected version of the
 875                   package, which means it is not necessary to
 876                   remove/keep */
 877                if (Cache[Pkg].InstallVer != Ver && Start.IsNegative() == true)
 878                {
 879                   if (Debug)
 880                      clog << "  Conflicts//Breaks against version "
 881                           << Ver.VerStr() << " for " << Pkg.Name()
 882                           << " but that is not InstVer, ignoring"
 883                           << endl;
 884                   continue;
 885                }
 886
 887                if (Debug == true)
 888                   clog << "  Considering " << Pkg.FullName(false) << ' ' << Scores[Pkg->ID] <<
 889                   " as a solution to " << I.FullName(false) << ' ' << Scores[I->ID] << endl;
 890
 891                /* Try to fix the package under consideration rather than
 892                   fiddle with the VList package */
 893                if (Scores[I->ID] <= Scores[Pkg->ID] ||
 894                    ((Cache[Start] & pkgDepCache::DepNow) == 0 &&
 895                     End.IsNegative() == false))
 896                {
 897                   // Try a little harder to fix protected packages..
 898                   if ((Flags[I->ID] & Protected) == Protected)
 899                   {
 900                      if (DoUpgrade(Pkg) == true)
 901                      {
 902                         if (Scores[Pkg->ID] > Scores[I->ID])
 903                            Scores[Pkg->ID] = Scores[I->ID];
 904                         break;
 905                      }
 906
 907                      continue;
 908                   }
 909
 910                   /* See if a keep will do, unless the package is protected,
 911                      then installing it will be necessary */
 912                   bool Installed = Cache[I].Install();
 913                   Cache.MarkKeep(I, false, false);
 914                   if (Cache[I].InstBroken() == false)
 915                   {
 916                      // Unwind operation will be keep now
 917                      if (OrOp == OrRemove)
 918                         OrOp = OrKeep;
 919
 920                      // Restore
 921                      if (InOr == true && Installed == true)
 922                         Cache.MarkInstall(I, false, 0, false);
 923
 924                      if (Debug == true)
 925                         clog << "  Holding Back " << I.FullName(false) << " rather than change " << Start.TargetPkg().FullName(false) << endl;
 926                   }
 927                   else
 928                   {
 929                      if (BrokenFix == false || DoUpgrade(I) == false)
 930                      {
 931                         // Consider other options
 932                         if (InOr == false || Cache[I].Garbage == true)
 933                         {
 934                            if (Debug == true)
 935                               clog << "  Removing " << I.FullName(false) << " rather than change " << Start.TargetPkg().FullName(false) << endl;
 936                            Cache.MarkDelete(I, false, 0, false);
 937                            if (Counter > 1 && Scores[Pkg->ID] > Scores[I->ID])
 938                               Scores[I->ID] = Scores[Pkg->ID];
 939                         }
 940                         else if (TryFixByInstall == true &&
 941                                  Start.TargetPkg()->CurrentVer == 0 &&
 942                                  Cache[Start.TargetPkg()].Delete() == false &&
 943                                  (Flags[Start.TargetPkg()->ID] & ToRemove) != ToRemove &&
 944                                  Cache.GetCandidateVer(Start.TargetPkg()).end() == false)
 945                         {
 946                            /* Before removing or keeping the package with the broken dependency
 947                               try instead to install the first not previously installed package
 948                               solving this dependency. This helps every time a previous solver
 949                               is removed by the resolver because of a conflict or alike but it is
 950                               dangerous as it could trigger new breaks/conflicts… */
 951                            if (Debug == true)
 952                               clog << "  Try Installing " << Start.TargetPkg() << " before changing " << I.FullName(false) << std::endl;
 953                            unsigned long const OldBroken = Cache.BrokenCount();
 954                            Cache.MarkInstall(Start.TargetPkg(), true, 1, false);
 955                            // FIXME: we should undo the complete MarkInstall process here
 956                            if (Cache[Start.TargetPkg()].InstBroken() == true || Cache.BrokenCount() > OldBroken)
 957                               Cache.MarkDelete(Start.TargetPkg(), false, 1, false);
 958                         }
 959                      }
 960                   }
 961
 962                   Change = true;
 963                   Done = true;
 964                   break;
 965                }
 966                else
 967                {
 968                   if (Start->Type == pkgCache::Dep::DpkgBreaks)
 969                   {
 970                      // first, try upgradring the package, if that
 971                      // does not help, the breaks goes onto the
 972                      // kill list
 973                      //
 974                      // FIXME: use DoUpgrade(Pkg) instead?
 975                      if (Cache[End] & pkgDepCache::DepGCVer)
 976                      {
 977                         if (Debug)
 978                            clog << "  Upgrading " << Pkg.FullName(false) << " due to Breaks field in " << I.FullName(false) << endl;
 979                         Cache.MarkInstall(Pkg, false, 0, false);
 980                         continue;
 981                      }
 982                   }
 983
 984                   // Skip adding to the kill list if it is protected
 985                   if ((Flags[Pkg->ID] & Protected) != 0)
 986                      continue;
 987
 988                   if (Debug == true)
 989                      clog << "  Added " << Pkg.FullName(false) << " to the remove list" << endl;
 990
 991                   LEnd->Pkg = Pkg;
 992                   LEnd->Dep = End;
 993                   LEnd++;
 994
 995                   if (Start.IsNegative() == false)
 996                      break;
 997                }
 998             }
 999
1000             // Hm, nothing can possibly satisify this dep. Nuke it.
1001             if (VList[0] == 0 &&
1002                 Start.IsNegative() == false &&
1003                 (Flags[I->ID] & Protected) != Protected)
1004             {
1005                bool Installed = Cache[I].Install();
1006                Cache.MarkKeep(I);
1007                if (Cache[I].InstBroken() == false)
1008                {
1009                   // Unwind operation will be keep now
1010                   if (OrOp == OrRemove)
1011                      OrOp = OrKeep;
1012
1013                   // Restore
1014                   if (InOr == true && Installed == true)
1015                      Cache.MarkInstall(I, false, 0, false);
1016
1017                   if (Debug == true)
1018                      clog << "  Holding Back " << I.FullName(false) << " because I can't find " << Start.TargetPkg().FullName(false) << endl;
1019                }
1020                else
1021                {
1022                   if (Debug == true)
1023                      clog << "  Removing " << I.FullName(false) << " because I can't find " << Start.TargetPkg().FullName(false) << endl;
1024                   if (InOr == false)
1025                      Cache.MarkDelete(I, false, 0, false);
1026                }
1027
1028                Change = true;
1029                Done = true;
1030             }
1031
1032             // Try some more
1033             if (InOr == true)
1034                continue;
1035
1036             if (Done == true)
1037                break;
1038          }
1039
1040          // Apply the kill list now
1041          if (Cache[I].InstallVer != 0)
1042          {
1043             for (PackageKill *J = KillList; J != LEnd; J++)
1044             {
1045                Change = true;
1046                if ((Cache[J->Dep] & pkgDepCache::DepGNow) == 0)
1047                {
1048                   if (J->Dep.IsNegative() == true)
1049                   {
1050                      if (Debug == true)
1051                         clog << "  Fixing " << I.FullName(false) << " via remove of " << J->Pkg.FullName(false) << endl;
1052                      Cache.MarkDelete(J->Pkg, false, 0, false);
1053                   }
1054                }
1055                else
1056                {
1057                   if (Debug == true)
1058                      clog << "  Fixing " << I.FullName(false) << " via keep of " << J->Pkg.FullName(false) << endl;
1059                   Cache.MarkKeep(J->Pkg, false, false);
1060                }
1061
1062                if (Counter > 1)
1063                {
1064                   if (Scores[I->ID] > Scores[J->Pkg->ID])
1065                      Scores[J->Pkg->ID] = Scores[I->ID];
1066                }
1067             }
1068          }
1069       }
1070    }
1071
1072    if (Debug == true)
1073       clog << "Done" << endl;
1074
1075    if (Cache.BrokenCount() != 0)
1076    {
1077       // See if this is the result of a hold
1078       pkgCache::PkgIterator I = Cache.PkgBegin();
1079       for (;I.end() != true; ++I)
1080       {
1081          if (Cache[I].InstBroken() == false)
1082             continue;
1083          if ((Flags[I->ID] & Protected) != Protected)
1084             return _error->Error(_("Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages."));
1085       }
1086       return _error->Error(_("Unable to correct problems, you have held broken packages."));
1087    }
1088
1089    // set the auto-flags (mvo: I'm not sure if we _really_ need this)
1090    pkgCache::PkgIterator I = Cache.PkgBegin();
1091    for (;I.end() != true; ++I) {
1092       if (Cache[I].NewInstall() && !(Flags[I->ID] & PreInstalled)) {
1093          if(_config->FindI("Debug::pkgAutoRemove",false)) {
1094             std::clog << "Resolve installed new pkg: " << I.FullName(false)
1095                       << " (now marking it as auto)" << std::endl;
1096          }
1097          Cache[I].Flags |= pkgCache::Flag::Auto;
1098       }
1099    }
1100
1101
1102    return true;
1103 }
1104                                                                         /*}}}*/
1105 // ProblemResolver::BreaksInstOrPolicy - Check if the given pkg is broken/*{{{*/
1106 // ---------------------------------------------------------------------
1107 /* This checks if the given package is broken either by a hard dependency
1108    (InstBroken()) or by introducing a new policy breakage e.g. new
1109    unsatisfied recommends for a package that was in "policy-good" state
1110
1111    Note that this is not perfect as it will ignore further breakage
1112    for already broken policy (recommends)
1113 */
1114 bool pkgProblemResolver::InstOrNewPolicyBroken(pkgCache::PkgIterator I)
1115 {
1116    // a broken install is always a problem
1117    if (Cache[I].InstBroken() == true)
1118    {
1119       if (Debug == true)
1120          std::clog << "  Dependencies are not satisfied for " << I << std::endl;
1121       return true;
1122    }
1123
1124    // a newly broken policy (recommends/suggests) is a problem
1125    if (Cache[I].NowPolicyBroken() == false &&
1126        Cache[I].InstPolicyBroken() == true)
1127    {
1128       if (Debug == true)
1129          std::clog << "  Policy breaks with upgrade of " << I << std::endl;
1130       return true;
1131    }
1132
1133    return false;
1134 }
1135                                                                         /*}}}*/
1136 // ProblemResolver::ResolveByKeep - Resolve problems using keep         /*{{{*/
1137 // ---------------------------------------------------------------------
1138 /* This is the work horse of the soft upgrade routine. It is very gental
1139    in that it does not install or remove any packages. It is assumed that the
1140    system was non-broken previously. */
1141 bool pkgProblemResolver::ResolveByKeep(OpProgress * const Progress)
1142 {
1143    std::string const solver = _config->Find("APT::Solver", "internal");
1144    if (solver != "internal")
1145       return EDSP::ResolveExternal(solver.c_str(), Cache, true, false, false, Progress);
1146    return ResolveByKeepInternal();
1147 }
1148                                                                         /*}}}*/
1149 // ProblemResolver::ResolveByKeepInternal - Resolve problems using keep /*{{{*/
1150 // ---------------------------------------------------------------------
1151 /* This is the work horse of the soft upgrade routine. It is very gental
1152    in that it does not install or remove any packages. It is assumed that the
1153    system was non-broken previously. */
1154 bool pkgProblemResolver::ResolveByKeepInternal()
1155 {
1156    pkgDepCache::ActionGroup group(Cache);
1157
1158    unsigned long Size = Cache.Head().PackageCount;
1159
1160    MakeScores();
1161
1162    /* We have to order the packages so that the broken fixing pass
1163       operates from highest score to lowest. This prevents problems when
1164       high score packages cause the removal of lower score packages that
1165       would cause the removal of even lower score packages. */
1166    pkgCache::Package **PList = new pkgCache::Package *[Size];
1167    pkgCache::Package **PEnd = PList;
1168    for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
1169       *PEnd++ = I;
1170    This = this;
1171    qsort(PList,PEnd - PList,sizeof(*PList),&ScoreSort);
1172
1173    if (_config->FindB("Debug::pkgProblemResolver::ShowScores",false) == true)
1174    {
1175       clog << "Show Scores" << endl;
1176       for (pkgCache::Package **K = PList; K != PEnd; K++)
1177          if (Scores[(*K)->ID] != 0)
1178          {
1179            pkgCache::PkgIterator Pkg(Cache,*K);
1180            clog << Scores[(*K)->ID] << ' ' << Pkg << std::endl;
1181          }
1182    }
1183
1184    if (Debug == true)
1185       clog << "Entering ResolveByKeep" << endl;
1186
1187    // Consider each broken package
1188    pkgCache::Package **LastStop = 0;
1189    for (pkgCache::Package **K = PList; K != PEnd; K++)
1190    {
1191       pkgCache::PkgIterator I(Cache,*K);
1192
1193       if (Cache[I].InstallVer == 0)
1194          continue;
1195
1196       if (InstOrNewPolicyBroken(I) == false)
1197          continue;
1198
1199       /* Keep the package. If this works then great, otherwise we have
1200          to be significantly more aggressive and manipulate its dependencies */
1201       if ((Flags[I->ID] & Protected) == 0)
1202       {
1203          if (Debug == true)
1204             clog << "Keeping package " << I.FullName(false) << endl;
1205          Cache.MarkKeep(I, false, false);
1206          if (InstOrNewPolicyBroken(I) == false)
1207          {
1208             K = PList - 1;
1209             continue;
1210          }
1211       }
1212
1213       // Isolate the problem dependencies
1214       for (pkgCache::DepIterator D = Cache[I].InstVerIter(Cache).DependsList(); D.end() == false;)
1215       {
1216          DepIterator Start;
1217          DepIterator End;
1218          D.GlobOr(Start,End);
1219
1220          // We only worry about critical deps.
1221          if (End.IsCritical() != true)
1222             continue;
1223
1224          // Dep is ok
1225          if ((Cache[End] & pkgDepCache::DepGInstall) == pkgDepCache::DepGInstall)
1226             continue;
1227
1228          /* Hm, the group is broken.. I suppose the best thing to do is to
1229             is to try every combination of keep/not-keep for the set, but thats
1230             slow, and this never happens, just be conservative and assume the
1231             list of ors is in preference and keep till it starts to work. */
1232          while (true)
1233          {
1234             if (Debug == true)
1235                clog << "Package " << I.FullName(false) << " " << Start << endl;
1236
1237             // Look at all the possible provides on this package
1238             SPtrArray<pkgCache::Version *> VList = Start.AllTargets();
1239             for (pkgCache::Version **V = VList; *V != 0; V++)
1240             {
1241                pkgCache::VerIterator Ver(Cache,*V);
1242                pkgCache::PkgIterator Pkg = Ver.ParentPkg();
1243
1244                // It is not keepable
1245                if (Cache[Pkg].InstallVer == 0 ||
1246                    Pkg->CurrentVer == 0)
1247                   continue;
1248
1249                if ((Flags[I->ID] & Protected) == 0)
1250                {
1251                   if (Debug == true)
1252                      clog << "  Keeping Package " << Pkg.FullName(false) << " due to " << Start.DepType() << endl;
1253                   Cache.MarkKeep(Pkg, false, false);
1254                }
1255
1256                if (InstOrNewPolicyBroken(I) == false)
1257                   break;
1258             }
1259
1260             if (InstOrNewPolicyBroken(I) == false)
1261                break;
1262
1263             if (Start == End)
1264                break;
1265             ++Start;
1266          }
1267
1268          if (InstOrNewPolicyBroken(I) == false)
1269             break;
1270       }
1271
1272       if (InstOrNewPolicyBroken(I) == true)
1273          continue;
1274
1275       // Restart again.
1276       if (K == LastStop) {
1277           // I is an iterator based off our temporary package list,
1278           // so copy the name we need before deleting the temporary list
1279           std::string const LoopingPackage = I.FullName(false);
1280           delete[] PList;
1281           return _error->Error("Internal Error, pkgProblemResolver::ResolveByKeep is looping on package %s.", LoopingPackage.c_str());
1282       }
1283       LastStop = K;
1284       K = PList - 1;
1285    }
1286
1287    delete[] PList;
1288    return true;
1289 }
1290                                                                         /*}}}*/
1291 // ProblemResolver::InstallProtect - deprecated cpu-eating no-op        /*{{{*/
1292 // ---------------------------------------------------------------------
1293 /* Actions issued with FromUser bit set are protected from further
1294    modification (expect by other calls with FromUser set) nowadays , so we
1295    don't need to reissue actions here, they are already set in stone. */
1296 void pkgProblemResolver::InstallProtect()
1297 {
1298    pkgDepCache::ActionGroup group(Cache);
1299
1300    for (pkgCache::PkgIterator I = Cache.PkgBegin(); I.end() == false; ++I)
1301    {
1302       if ((Flags[I->ID] & Protected) == Protected)
1303       {
1304          if ((Flags[I->ID] & ToRemove) == ToRemove)
1305             Cache.MarkDelete(I);
1306          else
1307          {
1308             // preserve the information whether the package was auto
1309             // or manually installed
1310             bool autoInst = (Cache[I].Flags & pkgCache::Flag::Auto);
1311             Cache.MarkInstall(I, false, 0, !autoInst);
1312          }
1313       }
1314    }
1315 }
1316                                                                         /*}}}*/
1317 // PrioSortList - Sort a list of versions by priority                   /*{{{*/
1318 // ---------------------------------------------------------------------
1319 /* This is ment to be used in conjunction with AllTargets to get a list
1320    of versions ordered by preference. */
1321 static pkgCache *PrioCache;
1322 static int PrioComp(const void *A,const void *B)
1323 {
1324    pkgCache::VerIterator L(*PrioCache,*(pkgCache::Version **)A);
1325    pkgCache::VerIterator R(*PrioCache,*(pkgCache::Version **)B);
1326
1327    if ((L.ParentPkg()->Flags & pkgCache::Flag::Essential) == pkgCache::Flag::Essential &&
1328        (R.ParentPkg()->Flags & pkgCache::Flag::Essential) != pkgCache::Flag::Essential)
1329      return 1;
1330    if ((L.ParentPkg()->Flags & pkgCache::Flag::Essential) != pkgCache::Flag::Essential &&
1331        (R.ParentPkg()->Flags & pkgCache::Flag::Essential) == pkgCache::Flag::Essential)
1332      return -1;
1333
1334    if ((L.ParentPkg()->Flags & pkgCache::Flag::Important) == pkgCache::Flag::Important &&
1335        (R.ParentPkg()->Flags & pkgCache::Flag::Important) != pkgCache::Flag::Important)
1336      return 1;
1337    if ((L.ParentPkg()->Flags & pkgCache::Flag::Important) != pkgCache::Flag::Important &&
1338        (R.ParentPkg()->Flags & pkgCache::Flag::Important) == pkgCache::Flag::Important)
1339      return -1;
1340
1341    if (L->Priority != R->Priority)
1342       return R->Priority - L->Priority;
1343    return strcmp(L.ParentPkg().Name(),R.ParentPkg().Name());
1344 }
1345 void pkgPrioSortList(pkgCache &Cache,pkgCache::Version **List)
1346 {
1347    unsigned long Count = 0;
1348    PrioCache = &Cache;
1349    for (pkgCache::Version **I = List; *I != 0; I++)
1350       Count++;
1351    qsort(List,Count,sizeof(*List),PrioComp);
1352 }
1353                                                                         /*}}}*/