tools/dsync-0.0/libdsync/filelistdb.cc

   1 // -*- mode: cpp; mode: fold -*-
   2 // Description                                                          /*{{{*/
   3 // $Id: filelistdb.cc,v 1.4 1999/02/27 08:00:05 jgg Exp $
   4 /* ######################################################################
   5
   6    File List Database
   7
   8    The mmap class should probably go someplace else..
   9
  10    ##################################################################### */
  11                                                                         /*}}}*/
  12 // Include files                                                        /*{{{*/
  13 #ifdef __GNUG__
  14 #pragma implementation "dsync/filelistdb.h"
  15 #endif
  16
  17 #include <dsync/filelistdb.h>
  18 #include <dsync/error.h>
  19                                                                         /*}}}*/
  20
  21 // FileListDB::dsFileListDB - Constructor                               /*{{{*/
  22 // ---------------------------------------------------------------------
  23 /* */
  24 dsFileListDB::dsFileListDB()
  25 {
  26 }
  27                                                                         /*}}}*/
  28 // FileListDB::Generate - Build the directory map                       /*{{{*/
  29 // ---------------------------------------------------------------------
  30 /* This sucks the offset of every directory record into a stl map for
  31    quick lookup. */
  32 bool dsFileListDB::Generate(dsFList::IO &IO)
  33 {
  34    // Iterate over the file
  35    dsFList List;
  36    while (List.Step(IO) == true)
  37    {
  38       // Record the current location so we can jump to it
  39       unsigned long Pos = IO.Tell();
  40       string LastSymlink = IO.LastSymlink;
  41
  42       if (List.Tag == dsFList::tTrailer)
  43          return true;
  44
  45       // We only index directory start records
  46       if (List.Tag != dsFList::tDirStart)
  47          continue;
  48
  49       // Store it in the map
  50       Location &Loc = Map[List.Dir.Name];
  51       Loc.Offset = Pos;
  52       Loc.LastSymlink = LastSymlink;
  53    }
  54
  55    return false;
  56 }
  57                                                                         /*}}}*/
  58 // FileListDB::Lookup - Find a directory and file                       /*{{{*/
  59 // ---------------------------------------------------------------------
  60 /* We use a caching scheme, if the last lookup is in the same directory
  61    we do not re-seek but mearly look at the next entries till termination
  62    then wraps around. In the case of a largely unchanged directory this
  63    gives huge speed increases. */
  64 bool dsFileListDB::Lookup(dsFList::IO &IO,const char *Dir,const char *File,
  65                           dsFList &List)
  66 {
  67    map<string,Location>::const_iterator I = Map.find(Dir);
  68    if (I == Map.end())
  69       return false;
  70
  71    // See if we should reseek
  72    bool Restart = true;
  73    if (LastDir != Dir || LastDir.empty() == true)
  74    {
  75       Restart = false;
  76       IO.LastSymlink = I->second.LastSymlink;
  77       if (IO.Seek(I->second.Offset) == false)
  78          return false;
  79       LastDir = Dir;
  80    }
  81
  82    List.Head = IO.Header;
  83    while (List.Step(IO) == true)
  84    {
  85       // Oops, ran out of directories
  86       if (List.Tag == dsFList::tDirEnd ||
  87           List.Tag == dsFList::tDirStart ||
  88           List.Tag == dsFList::tTrailer)
  89       {
  90          if (Restart == false)
  91          {
  92             LastDir = string();
  93             return false;
  94          }
  95
  96          Restart = false;
  97          IO.LastSymlink = I->second.LastSymlink;
  98          if (IO.Seek(I->second.Offset) == false)
  99             return false;
 100          LastDir = Dir;
 101
 102          continue;
 103       }
 104
 105       // Skip over non directory contents
 106       if (List.Tag == dsFList::tDirMarker ||
 107           List.Tag == dsFList::tDirEnd ||
 108           List.Tag == dsFList::tDirStart ||
 109           List.Entity == 0)
 110          continue;
 111
 112       if (List.Entity->Name == File)
 113          return true;
 114    }
 115    return false;
 116 }
 117                                                                         /*}}}*/
 118
 119 // MMapIO::dsMMapIO - Constructor                                       /*{{{*/
 120 // ---------------------------------------------------------------------
 121 /* */
 122 dsMMapIO::dsMMapIO(string File) : Fd(File,FileFd::ReadOnly),
 123               Map(Fd,MMap::Public | MMap::ReadOnly)
 124 {
 125    Pos = 0;
 126 }
 127                                                                         /*}}}*/
 128 // MMapIO::Read - Read bytes from the map                               /*{{{*/
 129 // ---------------------------------------------------------------------
 130 /* */
 131 bool dsMMapIO::Read(void *Buf,unsigned long Len)
 132 {
 133    if (Pos + Len > Map.Size())
 134       return _error->Error("Attempt to read past end of mmap");
 135    memcpy(Buf,(unsigned char *)Map.Data() + Pos,Len);
 136    Pos += Len;
 137    return true;
 138 }
 139                                                                         /*}}}*/
 140 // MMapIO::Write - Write bytes (fail)                                   /*{{{*/
 141 // ---------------------------------------------------------------------
 142 /* */
 143 bool dsMMapIO::Write(const void *Buf,unsigned long Len)
 144 {
 145    return _error->Error("Attempt to write to read only mmap");
 146 }
 147                                                                         /*}}}*/
 148 // MMapIO::Seek - Jump to a spot                                        /*{{{*/
 149 // ---------------------------------------------------------------------
 150 /* */
 151 bool dsMMapIO::Seek(unsigned long Bytes)
 152 {
 153    if (Bytes > Map.Size())
 154       return _error->Error("Attempt to seek past end of mmap");
 155    Pos = Bytes;
 156    return true;
 157 }
 158                                                                         /*}}}*/
 159 // MMapIO::Tell - Return the current location                           /*{{{*/
 160 // ---------------------------------------------------------------------
 161 /* */
 162 unsigned long dsMMapIO::Tell()
 163 {
 164    return Pos;
 165 }
 166                                                                         /*}}}*/