ftparchive/multicompress.h

   1 // -*- mode: cpp; mode: fold -*-
   2 // Description                                                          /*{{{*/
   3 // $Id: multicompress.h,v 1.2 2001/02/20 07:03:18 jgg Exp $
   4 /* ######################################################################
   5
   6    MultiCompressor
   7
   8    Multiple output class. Takes a single FILE* and writes it simultaneously
   9    to many compressed files. Then checks if the resulting output is
  10    different from any previous output and overwrites the old files. Care is
  11    taken to ensure that the new files are not generally readable while they
  12    are being written.
  13
  14    ##################################################################### */
  15                                                                         /*}}}*/
  16 #ifndef MULTICOMPRESS_H
  17 #define MULTICOMPRESS_H
  18
  19
  20
  21 #include <string>
  22 #include <apt-pkg/fileutl.h>
  23 #include <stdio.h>
  24 #include <sys/types.h>
  25
  26 class MultiCompress
  27 {
  28    // Enumeration of all supported compressors
  29    struct CompType
  30    {
  31       const char *Name;
  32       const char *Extension;
  33       const char *Binary;
  34       const char *CompArgs;
  35       const char *UnCompArgs;
  36       unsigned char Cost;
  37    };
  38
  39    // An output file
  40    struct Files
  41    {
  42       string Output;
  43       const CompType *CompressProg;
  44       Files *Next;
  45       FileFd TmpFile;
  46       pid_t CompressProc;
  47       time_t OldMTime;
  48       int Fd;
  49    };
  50
  51    Files *Outputs;
  52    pid_t Outputter;
  53    mode_t Permissions;
  54    static const CompType Compressors[];
  55
  56    bool OpenCompress(const CompType *Prog,pid_t &Pid,int FileFd,
  57                      int &OutFd,bool Comp);
  58    bool Child(int Fd);
  59    bool Start();
  60    bool Die();
  61
  62    public:
  63
  64    // The FD to write to for compression.
  65    FILE *Input;
  66    unsigned long UpdateMTime;
  67
  68    bool Finalize(unsigned long &OutSize);
  69    bool OpenOld(int &Fd,pid_t &Proc);
  70    bool CloseOld(int Fd,pid_t Proc);
  71    static bool GetStat(string Output,string Compress,struct stat &St);
  72
  73    MultiCompress(string Output,string Compress,mode_t Permissions,
  74                  bool Write = true);
  75    ~MultiCompress();
  76 };
  77
  78 #endif