// -*- mode: cpp; mode: fold -*- // Description /*{{{*/ // $Id: tagfile.cc,v 1.37.2.2 2003/12/31 16:02:30 mdz Exp $ /* ###################################################################### Fast scanner for RFC-822 type header information This uses a rotating buffer to load the package information into. The scanner runs over it and isolates and indexes a single section. ##################################################################### */ /*}}}*/ // Include Files /*{{{*/ #ifdef __GNUG__ #pragma implementation "apt-pkg/tagfile.h" #endif #include #include #include #include #include #include #include /*}}}*/ using std::string; // TagFile::pkgTagFile - Constructor /*{{{*/ // --------------------------------------------------------------------- /* */ pkgTagFile::pkgTagFile(FileFd *pFd,unsigned long Size) : Fd(*pFd), Size(Size) { if (Fd.IsOpen() == false || Fd.Size() == 0) { Buffer = 0; Start = End = Buffer = 0; iOffset = 0; Map = NULL; return; } Map = new MMap (Fd, MMap::Public | MMap::ReadOnly); Buffer = (char *) Map->Data (); Start = Buffer; End = Buffer + Map->Size (); iOffset = 0; } /*}}}*/ // TagFile::~pkgTagFile - Destructor /*{{{*/ // --------------------------------------------------------------------- /* */ pkgTagFile::~pkgTagFile() { delete Map; } /*}}}*/ // TagFile::Step - Advance to the next section /*{{{*/ // --------------------------------------------------------------------- /* If the Section Scanner fails we refill the buffer and try again. */ bool pkgTagFile::Step(pkgTagSection &Tag) { if (Start == End) return false; if (Tag.Scan(Start,End - Start) == false) { return _error->Error(_("Unable to parse package file %s (1)"), Fd.Name().c_str()); } Start += Tag.size(); iOffset += Tag.size(); Tag.Trim(); return true; } /*}}}*/ // TagFile::Jump - Jump to a pre-recorded location in the file /*{{{*/ // --------------------------------------------------------------------- /* This jumps to a pre-recorded file location and reads the record that is there */ bool pkgTagFile::Jump(pkgTagSection &Tag,unsigned long Offset) { // We are within a buffer space of the next hit.. if (Offset >= iOffset && iOffset + (End - Start) > Offset) { unsigned long Dist = Offset - iOffset; Start += Dist; iOffset += Dist; return Step(Tag); } // Reposition and reload.. iOffset = Offset; Start = Buffer + iOffset; if (Start != End && Tag.Scan(Start,End - Start) == false) return _error->Error(_("Unable to parse package file %s (2)"),Fd.Name().c_str()); return true; } /*}}}*/ // TagSection::Scan - Scan for the end of the header information /*{{{*/ // --------------------------------------------------------------------- /* This looks for the first double new line in the data stream. It also indexes the tags in the section. This very simple hash function for the first 3 letters gives very good performance on the debian package files */ inline static unsigned long AlphaHash(const char *Text, const char *End = 0) { unsigned long Res = 0; for (; Text != End && *Text != ':' && *Text != 0; Text++) Res = (unsigned long)(*Text) ^ (Res << 2); return Res & 0xFF; } bool pkgTagSection::Scan(const char *Start,unsigned long MaxLength) { const char *End = Start + MaxLength; Stop = Section = Start; memset(AlphaIndexes,0,sizeof(AlphaIndexes)); if (Stop == 0 || MaxLength == 0) return false; TagCount = 0; while (TagCount+1 < sizeof(Indexes)/sizeof(Indexes[0]) && Stop < End) { // Start a new index and add it to the hash if (isspace(Stop[0]) == 0) { Indexes[TagCount++] = Stop - Section; AlphaIndexes[AlphaHash(Stop,End)] = TagCount; } Stop = (const char *)memchr(Stop,'\n',End - Stop); if (Stop == 0) return false; for (; Stop+1 < End && Stop[1] == '\r'; Stop++); // Double newline marks the end of the record if (Stop+1 < End && Stop[1] == '\n') { Indexes[TagCount] = Stop - Section; for (; Stop < End && (Stop[0] == '\n' || Stop[0] == '\r'); Stop++); return true; } Stop++; } if ((Stop+1 >= End) && (End[-1] == '\n' || End[-1] == '\r')) { Indexes[TagCount] = (End - 1) - Section; return true; } return false; } /*}}}*/ // TagSection::Trim - Trim off any trailing garbage /*{{{*/ // --------------------------------------------------------------------- /* There should be exactly 1 newline at the end of the buffer, no more. */ void pkgTagSection::Trim() { for (; Stop > Section + 2 && (Stop[-2] == '\n' || Stop[-2] == '\r'); Stop--); } /*}}}*/ // TagSection::Find - Locate a tag /*{{{*/ // --------------------------------------------------------------------- /* This searches the section for a tag that matches the given string. */ bool pkgTagSection::Find(const char *Tag,unsigned &Pos) const { unsigned int Length = strlen(Tag); unsigned int I = AlphaIndexes[AlphaHash(Tag)]; if (I == 0) return false; I--; for (unsigned int Counter = 0; Counter != TagCount; Counter++, I = (I+1)%TagCount) { const char *St; St = Section + Indexes[I]; if (strncasecmp(Tag,St,Length) != 0) continue; // Make sure the colon is in the right place const char *C = St + Length; for (; isspace(*C) != 0; C++); if (*C != ':') continue; Pos = I; return true; } Pos = 0; return false; } /*}}}*/ // TagSection::Find - Locate a tag /*{{{*/ // --------------------------------------------------------------------- /* This searches the section for a tag that matches the given string. */ bool pkgTagSection::Find(const char *Tag,const char *&Start, const char *&End) const { unsigned int Length = strlen(Tag); unsigned int I = AlphaIndexes[AlphaHash(Tag)]; if (I == 0) return false; I--; for (unsigned int Counter = 0; Counter != TagCount; Counter++, I = (I+1)%TagCount) { const char *St; St = Section + Indexes[I]; if (strncasecmp(Tag,St,Length) != 0) continue; // Make sure the colon is in the right place const char *C = St + Length; for (; isspace(*C) != 0; C++); if (*C != ':') continue; // Strip off the gunk from the start end Start = C; End = Section + Indexes[I+1]; if (Start >= End) return _error->Error("Internal parsing error"); for (; (isspace(*Start) != 0 || *Start == ':') && Start < End; Start++); for (; isspace(End[-1]) != 0 && End > Start; End--); return true; } Start = End = 0; return false; } /*}}}*/ // TagSection::FindS - Find a string /*{{{*/ // --------------------------------------------------------------------- /* */ string pkgTagSection::FindS(const char *Tag) const { const char *Start; const char *End; if (Find(Tag,Start,End) == false) return string(); return string(Start,End); } /*}}}*/ // TagSection::FindI - Find an integer /*{{{*/ // --------------------------------------------------------------------- /* */ signed int pkgTagSection::FindI(const char *Tag,signed long Default) const { const char *Start; const char *Stop; if (Find(Tag,Start,Stop) == false) return Default; // Copy it into a temp buffer so we can use strtol char S[300]; if ((unsigned)(Stop - Start) >= sizeof(S)) return Default; strncpy(S,Start,Stop-Start); S[Stop - Start] = 0; char *End; signed long Result = strtol(S,&End,10); if (S == End) return Default; return Result; } /*}}}*/ // TagSection::FindFlag - Locate a yes/no type flag /*{{{*/ // --------------------------------------------------------------------- /* The bits marked in Flag are masked on/off in Flags */ bool pkgTagSection::FindFlag(const char *Tag,unsigned long &Flags, unsigned long Flag) const { const char *Start; const char *Stop; if (Find(Tag,Start,Stop) == false) return true; switch (StringToBool(string(Start,Stop))) { case 0: Flags &= ~Flag; return true; case 1: Flags |= Flag; return true; default: _error->Warning("Unknown flag value: %s",string(Start,Stop).c_str()); return true; } return true; } /*}}}*/ // TFRewrite - Rewrite a control record /*{{{*/ // --------------------------------------------------------------------- /* This writes the control record to stdout rewriting it as necessary. The override map item specificies the rewriting rules to follow. This also takes the time to sort the feild list. */ /* The order of this list is taken from dpkg source lib/parse.c the fieldinfos array. */ static const char *iTFRewritePackageOrder[] = { "Package", "Essential", "Status", "Priority", "Section", "Installed-Size", "Maintainer", "Architecture", "Source", "Version", "Revision", // Obsolete "Config-Version", // Obsolete "Replaces", "Provides", "Depends", "Pre-Depends", "Recommends", "Suggests", "Conflicts", "Conffiles", "Filename", "Size", "MD5Sum", "SHA1Sum", "MSDOS-Filename", // Obsolete "Description", 0}; static const char *iTFRewriteSourceOrder[] = {"Package", "Source", "Binary", "Version", "Priority", "Section", "Maintainer", "Build-Depends", "Build-Depends-Indep", "Build-Conflicts", "Build-Conflicts-Indep", "Architecture", "Standards-Version", "Format", "Directory", "Files", 0}; /* Two levels of initialization are used because gcc will set the symbol size of an array to the length of the array, causing dynamic relinking errors. Doing this makes the symbol size constant */ const char **TFRewritePackageOrder = iTFRewritePackageOrder; const char **TFRewriteSourceOrder = iTFRewriteSourceOrder; bool TFRewrite(FILE *Output,pkgTagSection const &Tags,const char *Order[], TFRewriteData *Rewrite) { unsigned char Visited[256]; // Bit 1 is Order, Bit 2 is Rewrite for (unsigned I = 0; I != 256; I++) Visited[I] = 0; // Set new tag up as necessary. for (unsigned int J = 0; Rewrite != 0 && Rewrite[J].Tag != 0; J++) { if (Rewrite[J].NewTag == 0) Rewrite[J].NewTag = Rewrite[J].Tag; } // Write all all of the tags, in order. for (unsigned int I = 0; Order[I] != 0; I++) { bool Rewritten = false; // See if this is a field that needs to be rewritten for (unsigned int J = 0; Rewrite != 0 && Rewrite[J].Tag != 0; J++) { if (strcasecmp(Rewrite[J].Tag,Order[I]) == 0) { Visited[J] |= 2; if (Rewrite[J].Rewrite != 0 && Rewrite[J].Rewrite[0] != 0) { if (isspace(Rewrite[J].Rewrite[0])) fprintf(Output,"%s:%s\n",Rewrite[J].NewTag,Rewrite[J].Rewrite); else fprintf(Output,"%s: %s\n",Rewrite[J].NewTag,Rewrite[J].Rewrite); } Rewritten = true; break; } } // See if it is in the fragment unsigned Pos; if (Tags.Find(Order[I],Pos) == false) continue; Visited[Pos] |= 1; if (Rewritten == true) continue; /* Write out this element, taking a moment to rewrite the tag in case of changes of case. */ const char *Start; const char *Stop; Tags.Get(Start,Stop,Pos); if (fputs(Order[I],Output) < 0) return _error->Errno("fputs","IO Error to output"); Start += strlen(Order[I]); if (fwrite(Start,Stop - Start,1,Output) != 1) return _error->Errno("fwrite","IO Error to output"); if (Stop[-1] != '\n') fprintf(Output,"\n"); } // Now write all the old tags that were missed. for (unsigned int I = 0; I != Tags.Count(); I++) { if ((Visited[I] & 1) == 1) continue; const char *Start; const char *Stop; Tags.Get(Start,Stop,I); const char *End = Start; for (; End < Stop && *End != ':'; End++); // See if this is a field that needs to be rewritten bool Rewritten = false; for (unsigned int J = 0; Rewrite != 0 && Rewrite[J].Tag != 0; J++) { if (stringcasecmp(Start,End,Rewrite[J].Tag) == 0) { Visited[J] |= 2; if (Rewrite[J].Rewrite != 0 && Rewrite[J].Rewrite[0] != 0) { if (isspace(Rewrite[J].Rewrite[0])) fprintf(Output,"%s:%s\n",Rewrite[J].NewTag,Rewrite[J].Rewrite); else fprintf(Output,"%s: %s\n",Rewrite[J].NewTag,Rewrite[J].Rewrite); } Rewritten = true; break; } } if (Rewritten == true) continue; // Write out this element if (fwrite(Start,Stop - Start,1,Output) != 1) return _error->Errno("fwrite","IO Error to output"); if (Stop[-1] != '\n') fprintf(Output,"\n"); } // Now write all the rewrites that were missed for (unsigned int J = 0; Rewrite != 0 && Rewrite[J].Tag != 0; J++) { if ((Visited[J] & 2) == 2) continue; if (Rewrite[J].Rewrite != 0 && Rewrite[J].Rewrite[0] != 0) { if (isspace(Rewrite[J].Rewrite[0])) fprintf(Output,"%s:%s\n",Rewrite[J].NewTag,Rewrite[J].Rewrite); else fprintf(Output,"%s: %s\n",Rewrite[J].NewTag,Rewrite[J].Rewrite); } } return true; } /*}}}*/