[apt.git] / apt-pkg / policy.cc

// -*- mode: cpp; mode: fold -*-
// Description								/*{{{*/
// $Id: policy.cc,v 1.10 2003/08/12 00:17:37 mdz Exp $
/* ######################################################################

   Package Version Policy implementation

   This is just a really simple wrapper around pkgVersionMatch with
   some added goodies to manage the list of things..

   See man apt_preferences for what value means what.

   ##################################################################### */
									/*}}}*/
// Include Files							/*{{{*/
#include<config.h>

#include <apt-pkg/policy.h>
#include <apt-pkg/configuration.h>
#include <apt-pkg/cachefilter.h>
#include <apt-pkg/tagfile.h>
#include <apt-pkg/strutl.h>
#include <apt-pkg/fileutl.h>
#include <apt-pkg/error.h>
#include <apt-pkg/sptr.h>
#include <apt-pkg/cacheiterators.h>
#include <apt-pkg/pkgcache.h>
#include <apt-pkg/versionmatch.h>

#include <ctype.h>
#include <stddef.h>
#include <string.h>
#include <string>
#include <vector>
#include <iostream>
#include <sstream>

#include <apti18n.h>
									/*}}}*/

using namespace std;

// Policy::Init - Startup and bind to a cache				/*{{{*/
// ---------------------------------------------------------------------
/* Set the defaults for operation. The default mode with no loaded policy
   file matches the V0 policy engine. */
pkgPolicy::pkgPolicy(pkgCache *Owner) : Pins(0), PFPriority(0), Cache(Owner)
{
   if (Owner == 0)
      return;
   PFPriority = new signed short[Owner->Head().PackageFileCount];
   Pins = new Pin[Owner->Head().PackageCount];

   for (unsigned long I = 0; I != Owner->Head().PackageCount; I++)
      Pins[I].Type = pkgVersionMatch::None;

   // The config file has a master override.
   string DefRel = _config->Find("APT::Default-Release");
   if (DefRel.empty() == false)
   {
      bool found = false;
      // FIXME: make ExpressionMatches static to use it here easily
      pkgVersionMatch vm("", pkgVersionMatch::None);
      for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
      {
	 if ((F->Archive != 0 && vm.ExpressionMatches(DefRel, F.Archive()) == true) ||
	     (F->Codename != 0 && vm.ExpressionMatches(DefRel, F.Codename()) == true) ||
	     (F->Version != 0 && vm.ExpressionMatches(DefRel, F.Version()) == true) ||
	     (DefRel.length() > 2 && DefRel[1] == '='))
	    found = true;
      }
      if (found == false)
	 _error->Error(_("The value '%s' is invalid for APT::Default-Release as such a release is not available in the sources"), DefRel.c_str());
      else
	 CreatePin(pkgVersionMatch::Release,"",DefRel,990);
   }
   InitDefaults();
}
									/*}}}*/
// Policy::InitDefaults - Compute the default selections		/*{{{*/
// ---------------------------------------------------------------------
/* */
bool pkgPolicy::InitDefaults()
{   
   // Initialize the priorities based on the status of the package file
   for (pkgCache::PkgFileIterator I = Cache->FileBegin(); I != Cache->FileEnd(); ++I)
   {
      PFPriority[I->ID] = 500;
      if ((I->Flags & pkgCache::Flag::NotSource) == pkgCache::Flag::NotSource)
	 PFPriority[I->ID] = 100;
      else if ((I->Flags & pkgCache::Flag::ButAutomaticUpgrades) == pkgCache::Flag::ButAutomaticUpgrades)
	 PFPriority[I->ID] = 100;
      else if ((I->Flags & pkgCache::Flag::NotAutomatic) == pkgCache::Flag::NotAutomatic)
	 PFPriority[I->ID] = 1;
   }

   // Apply the defaults..
   SPtrArray<bool> Fixed = new bool[Cache->HeaderP->PackageFileCount];
   memset(Fixed,0,sizeof(*Fixed)*Cache->HeaderP->PackageFileCount);
   StatusOverride = false;
   for (vector<Pin>::const_iterator I = Defaults.begin(); I != Defaults.end(); ++I)
   {
      pkgVersionMatch Match(I->Data,I->Type);
      for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
      {
	 if (Fixed[F->ID] == false && Match.FileMatch(F) == true)
	 {
	    PFPriority[F->ID] = I->Priority;

	    if (PFPriority[F->ID] >= 1000)
	       StatusOverride = true;

	    Fixed[F->ID] = true;
	 }
      }
   }

   if (_config->FindB("Debug::pkgPolicy",false) == true)
      for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
	 std::clog << "Prio of " << F.FileName() << ' ' << PFPriority[F->ID] << std::endl;

   return true;
}
									/*}}}*/
// Policy::GetCandidateVer - Get the candidate install version		/*{{{*/
// ---------------------------------------------------------------------
/* Evaluate the package pins and the default list to deteremine what the
   best package is. */
pkgCache::VerIterator pkgPolicy::GetCandidateVer(pkgCache::PkgIterator const &Pkg)
{
   // Look for a package pin and evaluate it.
   signed Max = GetPriority(Pkg);
   pkgCache::VerIterator Pref = GetMatch(Pkg);

   // Alternatives in case we can not find our package pin (Bug#512318).
   signed MaxAlt = 0;
   pkgCache::VerIterator PrefAlt;

   // no package = no candidate version
   if (Pkg.end() == true)
      return Pref;

   // packages with a pin lower than 0 have no newer candidate than the current version
   if (Max < 0)
      return Pkg.CurrentVer();

   /* Falling through to the default version.. Setting Max to zero
      effectively excludes everything <= 0 which are the non-automatic
      priorities.. The status file is given a prio of 100 which will exclude
      not-automatic sources, except in a single shot not-installed mode.

      The user pin is subject to the same priority rules as default 
      selections. Thus there are two ways to create a pin - a pin that
      tracks the default when the default is taken away, and a permanent
      pin that stays at that setting.
    */
   bool PrefSeen = false;
   for (pkgCache::VerIterator Ver = Pkg.VersionList(); Ver.end() == false; ++Ver)
   {
      /* Lets see if this version is the installed version */
      bool instVer = (Pkg.CurrentVer() == Ver);

      if (Pref == Ver)
	 PrefSeen = true;

      for (pkgCache::VerFileIterator VF = Ver.FileList(); VF.end() == false; ++VF)
      {
	 /* If this is the status file, and the current version is not the
	    version in the status file (ie it is not installed, or somesuch)
	    then it is not a candidate for installation, ever. This weeds
	    out bogus entries that may be due to config-file states, or
	    other. */
	 if ((VF.File()->Flags & pkgCache::Flag::NotSource) == pkgCache::Flag::NotSource &&
	     instVer == false)
	    continue;

	 signed Prio = PFPriority[VF.File()->ID];
	 if (Prio > Max)
	 {
	    Pref = Ver;
	    Max = Prio;
	    PrefSeen = true;
	 }
	 if (Prio > MaxAlt)
	 {
	    PrefAlt = Ver;
	    MaxAlt = Prio;
	 }
      }

      if (instVer == true && Max < 1000)
      {
	 /* Not having seen the Pref yet means we have a specific pin below 1000
	    on a version below the current installed one, so ignore the specific pin
	    as this would be a downgrade otherwise */
	 if (PrefSeen == false || Pref.end() == true)
	 {
	    Pref = Ver;
	    PrefSeen = true;
	 }
	 /* Elevate our current selection (or the status file itself) so that only
	    a downgrade can override it from now on */
	 Max = 999;

	 // Fast path optimize.
	 if (StatusOverride == false)
	    break;
      }
   }
   // If we do not find our candidate, use the one with the highest pin.
   // This means that if there is a version available with pin > 0; there
   // will always be a candidate (Closes: #512318)
   if (!Pref.IsGood() && MaxAlt > 0)
       Pref = PrefAlt;

   return Pref;
}
									/*}}}*/
// Policy::CreatePin - Create an entry in the pin table..		/*{{{*/
// ---------------------------------------------------------------------
/* For performance we have 3 tables, the default table, the main cache
   table (hashed to the cache). A blank package name indicates the pin
   belongs to the default table. Order of insertion matters here, the
   earlier defaults override later ones. */
void pkgPolicy::CreatePin(pkgVersionMatch::MatchType Type,string Name,
			  string Data,signed short Priority)
{
   if (Name.empty() == true)
   {
      Pin *P = &*Defaults.insert(Defaults.end(),Pin());
      P->Type = Type;
      P->Priority = Priority;
      P->Data = Data;
      return;
   }

   size_t found = Name.rfind(':');
   string Arch;
   if (found != string::npos) {
      Arch = Name.substr(found+1);
      Name.erase(found);
   }

   // Allow pinning by wildcards
   // TODO: Maybe we should always prefer specific pins over non-
   // specific ones.
   if (Name[0] == '/' || Name.find_first_of("*[?") != string::npos)
   {
      pkgVersionMatch match(Data, Type);
      for (pkgCache::GrpIterator G = Cache->GrpBegin(); G.end() != true; ++G)
	 if (match.ExpressionMatches(Name, G.Name()))
	 {
	    if (Arch.empty() == false)
	       CreatePin(Type, string(G.Name()).append(":").append(Arch), Data, Priority);
	    else
	       CreatePin(Type, G.Name(), Data, Priority);
	 }
      return;
   }

   // find the package (group) this pin applies to
   pkgCache::GrpIterator Grp = Cache->FindGrp(Name);
   bool matched = false;
   if (Grp.end() == false)
   {
      std::string MatchingArch;
      if (Arch.empty() == true)
	 MatchingArch = Cache->NativeArch();
      else
	 MatchingArch = Arch;
      APT::CacheFilter::PackageArchitectureMatchesSpecification pams(MatchingArch);
      for (pkgCache::PkgIterator Pkg = Grp.PackageList(); Pkg.end() != true; Pkg = Grp.NextPkg(Pkg))
      {
	 if (pams(Pkg.Arch()) == false)
	    continue;
	 Pin *P = Pins + Pkg->ID;
	 // the first specific stanza for a package is the ruler,
	 // all others need to be ignored
	 if (P->Type != pkgVersionMatch::None)
	    P = &*Unmatched.insert(Unmatched.end(),PkgPin(Pkg.FullName()));
	 P->Type = Type;
	 P->Priority = Priority;
	 P->Data = Data;
	 matched = true;
      }
   }

   if (matched == false)
   {
      PkgPin *P = &*Unmatched.insert(Unmatched.end(),PkgPin(Name));
      if (Arch.empty() == false)
	 P->Pkg.append(":").append(Arch);
      P->Type = Type;
      P->Priority = Priority;
      P->Data = Data;
      return;
   }
}
									/*}}}*/
// Policy::GetMatch - Get the matching version for a package pin	/*{{{*/
// ---------------------------------------------------------------------
/* */
pkgCache::VerIterator pkgPolicy::GetMatch(pkgCache::PkgIterator const &Pkg)
{
   const Pin &PPkg = Pins[Pkg->ID];
   if (PPkg.Type == pkgVersionMatch::None)
      return pkgCache::VerIterator(*Pkg.Cache());

   pkgVersionMatch Match(PPkg.Data,PPkg.Type);
   return Match.Find(Pkg);
}
									/*}}}*/
// Policy::GetPriority - Get the priority of the package pin		/*{{{*/
// ---------------------------------------------------------------------
/* */
APT_PURE signed short pkgPolicy::GetPriority(pkgCache::PkgIterator const &Pkg)
{
   if (Pins[Pkg->ID].Type != pkgVersionMatch::None)
      return Pins[Pkg->ID].Priority;
   return 0;
}
APT_PURE signed short pkgPolicy::GetPriority(pkgCache::PkgFileIterator const &File)
{
   return PFPriority[File->ID];
}
									/*}}}*/
// PreferenceSection class - Overriding the default TrimRecord method	/*{{{*/
// ---------------------------------------------------------------------
/* The preference file is a user generated file so the parser should
   therefore be a bit more friendly by allowing comments and new lines
   all over the place rather than forcing a special format */
class PreferenceSection : public pkgTagSection
{
   void TrimRecord(bool /*BeforeRecord*/, const char* &End)
   {
      for (; Stop < End && (Stop[0] == '\n' || Stop[0] == '\r' || Stop[0] == '#'); Stop++)
	 if (Stop[0] == '#')
	    Stop = (const char*) memchr(Stop,'\n',End-Stop);
   }
};
									/*}}}*/
// ReadPinDir - Load the pin files from this dir into a Policy		/*{{{*/
// ---------------------------------------------------------------------
/* This will load each pin file in the given dir into a Policy. If the
   given dir is empty the dir set in Dir::Etc::PreferencesParts is used.
   Note also that this method will issue a warning if the dir does not
   exists but it will return true in this case! */
bool ReadPinDir(pkgPolicy &Plcy,string Dir)
{
   if (Dir.empty() == true)
      Dir = _config->FindDir("Dir::Etc::PreferencesParts");

   if (DirectoryExists(Dir) == false)
   {
      _error->WarningE("DirectoryExists",_("Unable to read %s"),Dir.c_str());
      return true;
   }

   vector<string> const List = GetListOfFilesInDir(Dir, "pref", true, true);

   // Read the files
   for (vector<string>::const_iterator I = List.begin(); I != List.end(); ++I)
      if (ReadPinFile(Plcy, *I) == false)
	 return false;
   return true;
}
									/*}}}*/
// ReadPinFile - Load the pin file into a Policy			/*{{{*/
// ---------------------------------------------------------------------
/* I'd like to see the preferences file store more than just pin information
   but right now that is the only stuff I have to store. Later there will
   have to be some kind of combined super parser to get the data into all
   the right classes.. */
bool ReadPinFile(pkgPolicy &Plcy,string File)
{
   if (File.empty() == true)
      File = _config->FindFile("Dir::Etc::Preferences");

   if (RealFileExists(File) == false)
      return true;
   
   FileFd Fd(File,FileFd::ReadOnly);
   pkgTagFile TF(&Fd);
   if (_error->PendingError() == true)
      return false;
   
   PreferenceSection Tags;
   while (TF.Step(Tags) == true)
   {
      // can happen when there are only comments in a record
      if (Tags.Count() == 0)
         continue;

      string Name = Tags.FindS("Package");
      if (Name.empty() == true)
	 return _error->Error(_("Invalid record in the preferences file %s, no Package header"), File.c_str());
      if (Name == "*")
	 Name = string();
      
      const char *Start;
      const char *End;
      if (Tags.Find("Pin",Start,End) == false)
	 continue;
	 
      const char *Word = Start;
      for (; Word != End && isspace(*Word) == 0; Word++);

      // Parse the type..
      pkgVersionMatch::MatchType Type;
      if (stringcasecmp(Start,Word,"version") == 0 && Name.empty() == false)
	 Type = pkgVersionMatch::Version;
      else if (stringcasecmp(Start,Word,"release") == 0)
	 Type = pkgVersionMatch::Release;
      else if (stringcasecmp(Start,Word,"origin") == 0)
	 Type = pkgVersionMatch::Origin;
      else
      {
	 _error->Warning(_("Did not understand pin type %s"),string(Start,Word).c_str());
	 continue;
      }
      for (; Word != End && isspace(*Word) != 0; Word++);

      short int priority = Tags.FindI("Pin-Priority", 0);
      if (priority == 0)
      {
         _error->Warning(_("No priority (or zero) specified for pin"));
         continue;
      }

      istringstream s(Name);
      string pkg;
      while(!s.eof())
      {
	 s >> pkg;
         Plcy.CreatePin(Type, pkg, string(Word,End),priority);
      };
   }

   Plcy.InitDefaults();
   return true;
}
									/*}}}*/
Commit	Line	Data
b2e465d6 AL	1	// -- mode: cpp; mode: fold --
b2e465d6 AL	2	// Description /{{{/
56298634	3	// $Id: policy.cc,v 1.10 2003/08/12 00:17:37 mdz Exp $
b2e465d6 AL	4	/* ######################################################################
	5
	6	Package Version Policy implementation
3f732aa6	7
b2e465d6 AL	8	This is just a really simple wrapper around pkgVersionMatch with
b2e465d6 AL	9	some added goodies to manage the list of things..
3f732aa6 DK	10
	11	See man apt_preferences for what value means what.
	12
b2e465d6 AL	13	##################################################################### */
	14	/}}}/
	15	// Include Files /{{{/
ea542140 DK	16	#include<config.h>
ea542140 DK	17
b2e465d6 AL	18	#include <apt-pkg/policy.h>
b2e465d6 AL	19	#include <apt-pkg/configuration.h>
9ed80cdd	20	#include <apt-pkg/cachefilter.h>
b2e465d6 AL	21	#include <apt-pkg/tagfile.h>
b2e465d6 AL	22	#include <apt-pkg/strutl.h>
46e39c8e	23	#include <apt-pkg/fileutl.h>
b2e465d6 AL	24	#include <apt-pkg/error.h>
b2e465d6 AL	25	#include <apt-pkg/sptr.h>
453b82a3 DK	26	#include <apt-pkg/cacheiterators.h>
	27	#include <apt-pkg/pkgcache.h>
	28	#include <apt-pkg/versionmatch.h>
46e39c8e	29
453b82a3 DK	30	#include <ctype.h>
	31	#include <stddef.h>
	32	#include <string.h>
	33	#include <string>
	34	#include <vector>
e7b470ee	35	#include <iostream>
1c62ab24	36	#include <sstream>
ea542140 DK	37
ea542140 DK	38	#include <apti18n.h>
b2e465d6 AL	39	/}}}/
b2e465d6 AL	40
e7b470ee AL	41	using namespace std;
e7b470ee AL	42
b2e465d6 AL	43	// Policy::Init - Startup and bind to a cache /{{{/
	44	// ---------------------------------------------------------------------
	45	/* Set the defaults for operation. The default mode with no loaded policy
	46	file matches the V0 policy engine. */
	47	pkgPolicy::pkgPolicy(pkgCache *Owner) : Pins(0), PFPriority(0), Cache(Owner)
	48	{
3f732aa6	49	if (Owner == 0)
c55b8a54	50	return;
b2e465d6 AL	51	PFPriority = new signed short[Owner->Head().PackageFileCount];
	52	Pins = new Pin[Owner->Head().PackageCount];
	53
	54	for (unsigned long I = 0; I != Owner->Head().PackageCount; I++)
	55	Pins[I].Type = pkgVersionMatch::None;
	56
	57	// The config file has a master override.
	58	string DefRel = _config->Find("APT::Default-Release");
	59	if (DefRel.empty() == false)
a3bbbab7 DK	60	{
	61	bool found = false;
	62	// FIXME: make ExpressionMatches static to use it here easily
	63	pkgVersionMatch vm("", pkgVersionMatch::None);
	64	for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
	65	{
	66	if ((F->Archive != 0 && vm.ExpressionMatches(DefRel, F.Archive()) == true) \|\|
	67	(F->Codename != 0 && vm.ExpressionMatches(DefRel, F.Codename()) == true) \|\|
061c58b6 DK	68	(F->Version != 0 && vm.ExpressionMatches(DefRel, F.Version()) == true) \|\|
061c58b6 DK	69	(DefRel.length() > 2 && DefRel[1] == '='))
a3bbbab7 DK	70	found = true;
	71	}
	72	if (found == false)
	73	_error->Error(_("The value '%s' is invalid for APT::Default-Release as such a release is not available in the sources"), DefRel.c_str());
	74	else
	75	CreatePin(pkgVersionMatch::Release,"",DefRel,990);
	76	}
b2e465d6 AL	77	InitDefaults();
	78	}
	79	/}}}/
	80	// Policy::InitDefaults - Compute the default selections /{{{/
	81	// ---------------------------------------------------------------------
	82	/* */
	83	bool pkgPolicy::InitDefaults()
	84	{
	85	// Initialize the priorities based on the status of the package file
f7f0d6c7	86	for (pkgCache::PkgFileIterator I = Cache->FileBegin(); I != Cache->FileEnd(); ++I)
b2e465d6 AL	87	{
	88	PFPriority[I->ID] = 500;
	89	if ((I->Flags & pkgCache::Flag::NotSource) == pkgCache::Flag::NotSource)
	90	PFPriority[I->ID] = 100;
5ed56f93 DK	91	else if ((I->Flags & pkgCache::Flag::ButAutomaticUpgrades) == pkgCache::Flag::ButAutomaticUpgrades)
	92	PFPriority[I->ID] = 100;
	93	else if ((I->Flags & pkgCache::Flag::NotAutomatic) == pkgCache::Flag::NotAutomatic)
	94	PFPriority[I->ID] = 1;
b2e465d6 AL	95	}
	96
	97	// Apply the defaults..
20ebd488	98	SPtrArray<bool> Fixed = new bool[Cache->HeaderP->PackageFileCount];
b2e465d6	99	memset(Fixed,0,sizeof(Fixed)Cache->HeaderP->PackageFileCount);
b2e465d6	100	StatusOverride = false;
ab640001	101	for (vector<Pin>::const_iterator I = Defaults.begin(); I != Defaults.end(); ++I)
b2e465d6 AL	102	{
b2e465d6 AL	103	pkgVersionMatch Match(I->Data,I->Type);
f7f0d6c7	104	for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
b2e465d6	105	{
ab640001	106	if (Fixed[F->ID] == false && Match.FileMatch(F) == true)
b2e465d6	107	{
ab640001 DK	108	PFPriority[F->ID] = I->Priority;
ab640001 DK	109
3f732aa6	110	if (PFPriority[F->ID] >= 1000)
b2e465d6	111	StatusOverride = true;
ab640001	112
b2e465d6	113	Fixed[F->ID] = true;
ab640001 DK	114	}
ab640001 DK	115	}
b2e465d6 AL	116	}
	117
	118	if (_config->FindB("Debug::pkgPolicy",false) == true)
f7f0d6c7	119	for (pkgCache::PkgFileIterator F = Cache->FileBegin(); F != Cache->FileEnd(); ++F)
ab640001 DK	120	std::clog << "Prio of " << F.FileName() << ' ' << PFPriority[F->ID] << std::endl;
	121
	122	return true;
b2e465d6 AL	123	}
	124	/}}}/
	125	// Policy::GetCandidateVer - Get the candidate install version /{{{/
	126	// ---------------------------------------------------------------------
	127	/* Evaluate the package pins and the default list to deteremine what the
	128	best package is. */
9ee8287e	129	pkgCache::VerIterator pkgPolicy::GetCandidateVer(pkgCache::PkgIterator const &Pkg)
b2e465d6	130	{
b2e465d6	131	// Look for a package pin and evaluate it.
af87ab54 AL	132	signed Max = GetPriority(Pkg);
af87ab54 AL	133	pkgCache::VerIterator Pref = GetMatch(Pkg);
e7b470ee	134
8f5525e9 JAK	135	// Alternatives in case we can not find our package pin (Bug#512318).
	136	signed MaxAlt = 0;
	137	pkgCache::VerIterator PrefAlt;
	138
9f5bf66a DK	139	// no package = no candidate version
	140	if (Pkg.end() == true)
	141	return Pref;
	142
	143	// packages with a pin lower than 0 have no newer candidate than the current version
	144	if (Max < 0)
	145	return Pkg.CurrentVer();
	146
b2e465d6 AL	147	/* Falling through to the default version.. Setting Max to zero
	148	effectively excludes everything <= 0 which are the non-automatic
	149	priorities.. The status file is given a prio of 100 which will exclude
	150	not-automatic sources, except in a single shot not-installed mode.
3f732aa6	151
b2e465d6 AL	152	The user pin is subject to the same priority rules as default
	153	selections. Thus there are two ways to create a pin - a pin that
	154	tracks the default when the default is taken away, and a permanent
	155	pin that stays at that setting.
	156	*/
16808002	157	bool PrefSeen = false;
f7f0d6c7	158	for (pkgCache::VerIterator Ver = Pkg.VersionList(); Ver.end() == false; ++Ver)
10639577	159	{
9ee8287e DK	160	/* Lets see if this version is the installed version */
9ee8287e DK	161	bool instVer = (Pkg.CurrentVer() == Ver);
9ee8287e	162
16808002 DK	163	if (Pref == Ver)
	164	PrefSeen = true;
	165
f7f0d6c7	166	for (pkgCache::VerFileIterator VF = Ver.FileList(); VF.end() == false; ++VF)
b2e465d6	167	{
6aeda9fa AL	168	/* If this is the status file, and the current version is not the
	169	version in the status file (ie it is not installed, or somesuch)
	170	then it is not a candidate for installation, ever. This weeds
	171	out bogus entries that may be due to config-file states, or
	172	other. */
	173	if ((VF.File()->Flags & pkgCache::Flag::NotSource) == pkgCache::Flag::NotSource &&
9ee8287e	174	instVer == false)
6aeda9fa	175	continue;
9ee8287e	176
b2e465d6 AL	177	signed Prio = PFPriority[VF.File()->ID];
	178	if (Prio > Max)
	179	{
	180	Pref = Ver;
	181	Max = Prio;
16808002	182	PrefSeen = true;
8f5525e9 JAK	183	}
	184	if (Prio > MaxAlt)
	185	{
	186	PrefAlt = Ver;
	187	MaxAlt = Prio;
16808002 DK	188	}
	189	}
	190
9ee8287e	191	if (instVer == true && Max < 1000)
b2e465d6	192	{
16808002 DK	193	/* Not having seen the Pref yet means we have a specific pin below 1000
	194	on a version below the current installed one, so ignore the specific pin
	195	as this would be a downgrade otherwise */
	196	if (PrefSeen == false \|\| Pref.end() == true)
	197	{
	198	Pref = Ver;
	199	PrefSeen = true;
	200	}
3f732aa6 DK	201	/* Elevate our current selection (or the status file itself) so that only
	202	a downgrade can override it from now on */
	203	Max = 999;
16808002	204
b2e465d6 AL	205	// Fast path optimize.
	206	if (StatusOverride == false)
	207	break;
16808002	208	}
b2e465d6	209	}
8f5525e9 JAK	210	// If we do not find our candidate, use the one with the highest pin.
	211	// This means that if there is a version available with pin > 0; there
	212	// will always be a candidate (Closes: #512318)
	213	if (!Pref.IsGood() && MaxAlt > 0)
	214	Pref = PrefAlt;
9ee8287e	215
b2e465d6 AL	216	return Pref;
	217	}
	218	/}}}/
	219	// Policy::CreatePin - Create an entry in the pin table.. /{{{/
	220	// ---------------------------------------------------------------------
	221	/* For performance we have 3 tables, the default table, the main cache
	222	table (hashed to the cache). A blank package name indicates the pin
	223	belongs to the default table. Order of insertion matters here, the
	224	earlier defaults override later ones. */
	225	void pkgPolicy::CreatePin(pkgVersionMatch::MatchType Type,string Name,
	226	string Data,signed short Priority)
	227	{
b2e465d6	228	if (Name.empty() == true)
b2e465d6	229	{
00c6e1a3	230	Pin P = &Defaults.insert(Defaults.end(),Pin());
4a6d2163 DK	231	P->Type = Type;
	232	P->Priority = Priority;
	233	P->Data = Data;
	234	return;
	235	}
00c6e1a3 MV	236
	237	size_t found = Name.rfind(':');
	238	string Arch;
	239	if (found != string::npos) {
	240	Arch = Name.substr(found+1);
	241	Name.erase(found);
	242	}
	243
1a4c9766 JAK	244	// Allow pinning by wildcards
	245	// TODO: Maybe we should always prefer specific pins over non-
	246	// specific ones.
a8d7c101 DK	247	if (Name[0] == '/' \|\| Name.find_first_of("*[?") != string::npos)
	248	{
	249	pkgVersionMatch match(Data, Type);
	250	for (pkgCache::GrpIterator G = Cache->GrpBegin(); G.end() != true; ++G)
	251	if (match.ExpressionMatches(Name, G.Name()))
00c6e1a3 MV	252	{
	253	if (Arch.empty() == false)
	254	CreatePin(Type, string(G.Name()).append(":").append(Arch), Data, Priority);
	255	else
	256	CreatePin(Type, G.Name(), Data, Priority);
	257	}
1a4c9766 JAK	258	return;
1a4c9766 JAK	259	}
4a6d2163	260
00c6e1a3	261	// find the package (group) this pin applies to
9ed80cdd DK	262	pkgCache::GrpIterator Grp = Cache->FindGrp(Name);
	263	bool matched = false;
	264	if (Grp.end() == false)
	265	{
	266	std::string MatchingArch;
	267	if (Arch.empty() == true)
	268	MatchingArch = Cache->NativeArch();
	269	else
	270	MatchingArch = Arch;
	271	APT::CacheFilter::PackageArchitectureMatchesSpecification pams(MatchingArch);
	272	for (pkgCache::PkgIterator Pkg = Grp.PackageList(); Pkg.end() != true; Pkg = Grp.NextPkg(Pkg))
	273	{
	274	if (pams(Pkg.Arch()) == false)
	275	continue;
	276	Pin *P = Pins + Pkg->ID;
	277	// the first specific stanza for a package is the ruler,
	278	// all others need to be ignored
	279	if (P->Type != pkgVersionMatch::None)
	280	P = &*Unmatched.insert(Unmatched.end(),PkgPin(Pkg.FullName()));
	281	P->Type = Type;
	282	P->Priority = Priority;
	283	P->Data = Data;
	284	matched = true;
	285	}
00c6e1a3 MV	286	}
00c6e1a3 MV	287
9ed80cdd	288	if (matched == false)
4a6d2163	289	{
00c6e1a3 MV	290	PkgPin P = &Unmatched.insert(Unmatched.end(),PkgPin(Name));
	291	if (Arch.empty() == false)
	292	P->Pkg.append(":").append(Arch);
	293	P->Type = Type;
	294	P->Priority = Priority;
	295	P->Data = Data;
	296	return;
	297	}
b2e465d6 AL	298	}
b2e465d6 AL	299	/}}}/
af87ab54 AL	300	// Policy::GetMatch - Get the matching version for a package pin /{{{/
	301	// ---------------------------------------------------------------------
	302	/* */
9ee8287e	303	pkgCache::VerIterator pkgPolicy::GetMatch(pkgCache::PkgIterator const &Pkg)
af87ab54 AL	304	{
af87ab54 AL	305	const Pin &PPkg = Pins[Pkg->ID];
9ee8287e DK	306	if (PPkg.Type == pkgVersionMatch::None)
	307	return pkgCache::VerIterator(*Pkg.Cache());
	308
	309	pkgVersionMatch Match(PPkg.Data,PPkg.Type);
	310	return Match.Find(Pkg);
af87ab54 AL	311	}
	312	/}}}/
	313	// Policy::GetPriority - Get the priority of the package pin /{{{/
	314	// ---------------------------------------------------------------------
	315	/* */
a02db58f	316	APT_PURE signed short pkgPolicy::GetPriority(pkgCache::PkgIterator const &Pkg)
af87ab54 AL	317	{
af87ab54 AL	318	if (Pins[Pkg->ID].Type != pkgVersionMatch::None)
af87ab54	319	return Pins[Pkg->ID].Priority;
af87ab54	320	return 0;
6d38011b	321	}
a02db58f	322	APT_PURE signed short pkgPolicy::GetPriority(pkgCache::PkgFileIterator const &File)
6d38011b DK	323	{
6d38011b DK	324	return PFPriority[File->ID];
af87ab54 AL	325	}
af87ab54 AL	326	/}}}/
81e9789b MV	327	// PreferenceSection class - Overriding the default TrimRecord method /{{{/
	328	// ---------------------------------------------------------------------
	329	/* The preference file is a user generated file so the parser should
	330	therefore be a bit more friendly by allowing comments and new lines
	331	all over the place rather than forcing a special format */
	332	class PreferenceSection : public pkgTagSection
	333	{
65512241	334	void TrimRecord(bool /BeforeRecord/, const char* &End)
81e9789b MV	335	{
	336	for (; Stop < End && (Stop[0] == '\n' \|\| Stop[0] == '\r' \|\| Stop[0] == '#'); Stop++)
	337	if (Stop[0] == '#')
	338	Stop = (const char*) memchr(Stop,'\n',End-Stop);
	339	}
	340	};
	341	/}}}/
ef1dff93 DK	342	// ReadPinDir - Load the pin files from this dir into a Policy /{{{/
ef1dff93 DK	343	// ---------------------------------------------------------------------
6009e60d DK	344	/* This will load each pin file in the given dir into a Policy. If the
	345	given dir is empty the dir set in Dir::Etc::PreferencesParts is used.
	346	Note also that this method will issue a warning if the dir does not
	347	exists but it will return true in this case! */
e68ca100 JAK	348	bool ReadPinDir(pkgPolicy &Plcy,string Dir)
	349	{
	350	if (Dir.empty() == true)
	351	Dir = _config->FindDir("Dir::Etc::PreferencesParts");
	352
448eaf8b	353	if (DirectoryExists(Dir) == false)
6009e60d	354	{
448eaf8b	355	_error->WarningE("DirectoryExists",_("Unable to read %s"),Dir.c_str());
6009e60d DK	356	return true;
	357	}
	358
b39c1859	359	vector<string> const List = GetListOfFilesInDir(Dir, "pref", true, true);
e68ca100 JAK	360
e68ca100 JAK	361	// Read the files
f7f0d6c7	362	for (vector<string>::const_iterator I = List.begin(); I != List.end(); ++I)
e68ca100 JAK	363	if (ReadPinFile(Plcy, *I) == false)
	364	return false;
	365	return true;
	366	}
81e9789b	367	/}}}/
b2e465d6 AL	368	// ReadPinFile - Load the pin file into a Policy /{{{/
	369	// ---------------------------------------------------------------------
	370	/* I'd like to see the preferences file store more than just pin information
	371	but right now that is the only stuff I have to store. Later there will
	372	have to be some kind of combined super parser to get the data into all
	373	the right classes.. */
	374	bool ReadPinFile(pkgPolicy &Plcy,string File)
	375	{
	376	if (File.empty() == true)
	377	File = _config->FindFile("Dir::Etc::Preferences");
	378
36f1098a	379	if (RealFileExists(File) == false)
b2e465d6 AL	380	return true;
	381
	382	FileFd Fd(File,FileFd::ReadOnly);
	383	pkgTagFile TF(&Fd);
	384	if (_error->PendingError() == true)
	385	return false;
	386
81e9789b	387	PreferenceSection Tags;
b2e465d6 AL	388	while (TF.Step(Tags) == true)
b2e465d6 AL	389	{
75ab11ae MV	390	// can happen when there are only comments in a record
	391	if (Tags.Count() == 0)
	392	continue;
	393
b2e465d6 AL	394	string Name = Tags.FindS("Package");
b2e465d6 AL	395	if (Name.empty() == true)
e68ca100	396	return _error->Error(_("Invalid record in the preferences file %s, no Package header"), File.c_str());
b2e465d6 AL	397	if (Name == "*")
	398	Name = string();
	399
	400	const char *Start;
	401	const char *End;
	402	if (Tags.Find("Pin",Start,End) == false)
	403	continue;
	404
	405	const char *Word = Start;
	406	for (; Word != End && isspace(*Word) == 0; Word++);
	407
	408	// Parse the type..
	409	pkgVersionMatch::MatchType Type;
	410	if (stringcasecmp(Start,Word,"version") == 0 && Name.empty() == false)
	411	Type = pkgVersionMatch::Version;
	412	else if (stringcasecmp(Start,Word,"release") == 0)
	413	Type = pkgVersionMatch::Release;
	414	else if (stringcasecmp(Start,Word,"origin") == 0)
	415	Type = pkgVersionMatch::Origin;
	416	else
	417	{
	418	_error->Warning(_("Did not understand pin type %s"),string(Start,Word).c_str());
	419	continue;
	420	}
	421	for (; Word != End && isspace(*Word) != 0; Word++);
	422
56298634 AL	423	short int priority = Tags.FindI("Pin-Priority", 0);
	424	if (priority == 0)
	425	{
	426	_error->Warning(_("No priority (or zero) specified for pin"));
	427	continue;
	428	}
	429
1c62ab24 MV	430	istringstream s(Name);
	431	string pkg;
	432	while(!s.eof())
	433	{
	434	s >> pkg;
	435	Plcy.CreatePin(Type, pkg, string(Word,End),priority);
	436	};
b2e465d6 AL	437	}
	438
	439	Plcy.InitDefaults();
	440	return true;
	441	}
	442	/}}}/