deblistparser.cpp

// ListParser::ParseDepends - Parse a dependency element		/*{{{*/
// ---------------------------------------------------------------------
/* This parses the dependency elements out of a standard string in place,
   bit by bit. */
const char *debListParser::ParseDepends(const char *Start,const char *Stop,
               std::string &Package,std::string &Ver,unsigned int &Op)
   { return ParseDepends(Start, Stop, Package, Ver, Op, false, true, false); }
const char *debListParser::ParseDepends(const char *Start,const char *Stop,
               std::string &Package,std::string &Ver,unsigned int &Op,
               bool const &ParseArchFlags)
   { return ParseDepends(Start, Stop, Package, Ver, Op, ParseArchFlags, true, false); }
const char *debListParser::ParseDepends(const char *Start,const char *Stop,
               std::string &Package,std::string &Ver,unsigned int &Op,
               bool const &ParseArchFlags, bool const &StripMultiArch)
   { return ParseDepends(Start, Stop, Package, Ver, Op, ParseArchFlags, StripMultiArch, false); }
const char *debListParser::ParseDepends(const char *Start,const char *Stop,
					string &Package,string &Ver,
					unsigned int &Op, bool const &ParseArchFlags,
					bool const &StripMultiArch,
					bool const &ParseRestrictionsList)
{
   // Strip off leading space
   for (;Start != Stop && isspace(*Start) != 0; ++Start);
   
   // Parse off the package name
   const char *I = Start;
   for (;I != Stop && isspace(*I) == 0 && *I != '(' && *I != ')' &&
	*I != ',' && *I != '|' && *I != '[' && *I != ']' &&
	*I != '<' && *I != '>'; ++I);
   
   // Malformed, no '('
   if (I != Stop && *I == ')')
      return 0;

   if (I == Start)
      return 0;
   
   // Stash the package name
   Package.assign(Start,I - Start);

   // We don't want to confuse library users which can't handle MultiArch
   string const arch = _config->Find("APT::Architecture");
   if (StripMultiArch == true) {
      size_t const found = Package.rfind(':');
      if (found != string::npos &&
	  (strcmp(Package.c_str() + found, ":any") == 0 ||
	   strcmp(Package.c_str() + found, ":native") == 0 ||
	   strcmp(Package.c_str() + found + 1, arch.c_str()) == 0))
	 Package = Package.substr(0,found);
   }

   // Skip white space to the '('
   for (;I != Stop && isspace(*I) != 0 ; I++);
   
   // Parse a version
   if (I != Stop && *I == '(')
   {
      // Skip the '('
      for (I++; I != Stop && isspace(*I) != 0 ; I++);
      if (I + 3 >= Stop)
	 return 0;
      I = ConvertRelation(I,Op);
      
      // Skip whitespace
      for (;I != Stop && isspace(*I) != 0; I++);
      Start = I;
      I = (const char*) memchr(I, ')', Stop - I);
      if (I == NULL || Start == I)
	 return 0;
      
      // Skip trailing whitespace
      const char *End = I;
      for (; End > Start && isspace(End[-1]); End--);
      
      Ver.assign(Start,End-Start);
      I++;
   }
   else
   {
      Ver.clear();
      Op = pkgCache::Dep::NoOp;
   }
   
   // Skip whitespace
   for (;I != Stop && isspace(*I) != 0; I++);

   if (ParseArchFlags == true)
   {
      APT::CacheFilter::PackageArchitectureMatchesSpecification matchesArch(arch, false);

      // Parse an architecture
      if (I != Stop && *I == '[')
      {
	 ++I;
	 // malformed
	 if (unlikely(I == Stop))
	    return 0;

	 const char *End = I;
	 bool Found = false;
	 bool NegArch = false;
	 while (I != Stop)
	 {
	    // look for whitespace or ending ']'
	    for (;End != Stop && !isspace(*End) && *End != ']'; ++End);

	    if (unlikely(End == Stop))
	       return 0;

	    if (*I == '!')
	    {
	       NegArch = true;
	       ++I;
	    }

	    std::string arch(I, End);
	    if (arch.empty() == false && matchesArch(arch.c_str()) == true)
	    {
	       Found = true;
	       if (I[-1] != '!')
		  NegArch = false;
	       // we found a match, so fast-forward to the end of the wildcards
	       for (; End != Stop && *End != ']'; ++End);
	    }

	    if (*End++ == ']') {
	       I = End;
	       break;
	    }

	    I = End;
	    for (;I != Stop && isspace(*I) != 0; I++);
	 }

	 if (NegArch == true)
	    Found = !Found;

	 if (Found == false)
	    Package = ""; /* not for this arch */
      }

      // Skip whitespace
      for (;I != Stop && isspace(*I) != 0; I++);
   }

   if (ParseRestrictionsList == true)
   {
      // Parse a restrictions formula which is in disjunctive normal form:
      // (foo AND bar) OR (blub AND bla)

      std::vector<string> const profiles = APT::Configuration::getBuildProfiles();

      // if the next character is a restriction list, then by default the
      // dependency does not apply and the conditions have to be checked
      // if the next character is not a restriction list, then by default the
      // dependency applies
      bool applies1 = (*I != '<');
      while (I != Stop)
      {
	 if (*I != '<')
	     break;

	 ++I;
	 // malformed
	 if (unlikely(I == Stop))
	    return 0;

	 const char *End = I;

	 // if of the prior restriction list is already fulfilled, then
	 // we can just skip to the end of the current list
	 if (applies1) {
	    for (;End != Stop && *End != '>'; ++End);
	    I = ++End;
	    // skip whitespace
	    for (;I != Stop && isspace(*I) != 0; I++);
	 } else {
	    bool applies2 = true;
	    // all the conditions inside a restriction list have to be
	    // met so once we find one that is not met, we can skip to
	    // the end of this list
	    while (I != Stop)
	    {
	       // look for whitespace or ending '>'
	       // End now points to the character after the current term
	       for (;End != Stop && !isspace(*End) && *End != '>'; ++End);

	       if (unlikely(End == Stop))
		  return 0;

	       bool NegRestriction = false;
	       if (*I == '!')
	       {
		  NegRestriction = true;
		  ++I;
	       }

	       std::string restriction(I, End);

	       if (restriction.empty() == false && profiles.empty() == false &&
		  std::find(profiles.begin(), profiles.end(), restriction) != profiles.end())
	       {
		  if (NegRestriction) {
		     applies2 = false;
		     // since one of the terms does not apply we don't have to check the others
		     for (; End != Stop && *End != '>'; ++End);
		  }
	       } else {
		  if (!NegRestriction) {
		     applies2 = false;
		     // since one of the terms does not apply we don't have to check the others
		     for (; End != Stop && *End != '>'; ++End);
		  }
	       }

	       if (*End++ == '>') {
		  I = End;
		  // skip whitespace
		  for (;I != Stop && isspace(*I) != 0; I++);
		  break;
	       }

	       I = End;
	       // skip whitespace
	       for (;I != Stop && isspace(*I) != 0; I++);
	    }
	    if (applies2) {
	       applies1 = true;
	    }
	 }
      }

      if (applies1 == false) {
	 Package = ""; //not for this restriction
      }
   }

   if (I != Stop && *I == '|')
      Op |= pkgCache::Dep::Or;
   
   if (I == Stop || *I == ',' || *I == '|')
   {
      if (I != Stop)
	 for (I++; I != Stop && isspace(*I) != 0; I++);
      return I;
   }
   
   return 0;
}
									/*}}}*/
// ListParser::ParseDepends - Parse a dependency list			/*{{{*/
// ---------------------------------------------------------------------
/* This is the higher level depends parser. It takes a tag and generates
   a complete depends tree for the given version. */
bool debListParser::ParseDepends(pkgCache::VerIterator &Ver,
				 const char *Tag,unsigned int Type)
{
   const char *Start;
   const char *Stop;
   if (Section.Find(Tag,Start,Stop) == false)
      return true;

   string const pkgArch = Ver.Arch();

   while (1)
   {
      string Package;
      string Version;
      unsigned int Op;

      Start = ParseDepends(Start, Stop, Package, Version, Op, false, false, false);
      if (Start == 0)
	 return _error->Error("Problem parsing dependency %s",Tag);
      size_t const found = Package.rfind(':');

      // If negative is unspecific it needs to apply on all architectures
      if (MultiArchEnabled == true && found == string::npos &&
	  (Type == pkgCache::Dep::Conflicts ||
	   Type == pkgCache::Dep::DpkgBreaks ||
	   Type == pkgCache::Dep::Replaces))
      {
	 for (std::vector<std::string>::const_iterator a = Architectures.begin();
	      a != Architectures.end(); ++a)
	    if (NewDepends(Ver,Package,*a,Version,Op,Type) == false)
	       return false;
	 if (NewDepends(Ver,Package,"none",Version,Op,Type) == false)
	    return false;
      }
      else if (found != string::npos &&
	       strcmp(Package.c_str() + found, ":any") != 0)
      {
	 string Arch = Package.substr(found+1, string::npos);
	 Package = Package.substr(0, found);
	 // Such dependencies are not supposed to be accepted …
	 // … but this is probably the best thing to do.
	 if (Arch == "native")
	    Arch = _config->Find("APT::Architecture");
	 if (NewDepends(Ver,Package,Arch,Version,Op,Type) == false)
	    return false;
      }
      else
      {
	 if (NewDepends(Ver,Package,pkgArch,Version,Op,Type) == false)
	    return false;
	 if ((Type == pkgCache::Dep::Conflicts ||
	      Type == pkgCache::Dep::DpkgBreaks ||
	      Type == pkgCache::Dep::Replaces) &&
	     NewDepends(Ver, Package,
			(pkgArch != "none") ? "none" : _config->Find("APT::Architecture"),
			Version,Op,Type) == false)
	    return false;
      }
      if (Start == Stop)
	 break;
   }
   return true;
}