apt-pkg/acquire.h

   1 // -*- mode: cpp; mode: fold -*-
   2 // Description                                                          /*{{{*/
   3 // $Id: acquire.h,v 1.4 1998/10/24 04:58:02 jgg Exp $
   4 /* ######################################################################
   5
   6    Acquire - File Acquiration
   7
   8    This module contians the Acquire system. It is responsible for bringing
   9    files into the local pathname space. It deals with URIs for files and
  10    URI handlers responsible for downloading or finding the URIs.
  11
  12    Each file to download is represented by an Acquire::Item class subclassed
  13    into a specialization. The Item class can add itself to several URI
  14    acquire queues each prioritized by the download scheduler. When the
  15    system is run the proper URI handlers are spawned and the the acquire
  16    queues are fed into the handlers by the schedular until the queues are
  17    empty. This allows for an Item to be downloaded from an alternate source
  18    if the first try turns out to fail. It also alows concurrent downloading
  19    of multiple items from multiple sources as well as dynamic balancing
  20    of load between the sources.
  21
  22    Schedualing of downloads is done on a first ask first get basis. This
  23    preserves the order of the download as much as possible. And means the
  24    fastest source will tend to process the largest number of files.
  25
  26    Internal methods and queues for performing gzip decompression,
  27    md5sum hashing and file copying are provided to allow items to apply
  28    a number of transformations to the data files they are working with.
  29
  30    ##################################################################### */
  31                                                                         /*}}}*/
  32 #ifndef PKGLIB_ACQUIRE_H
  33 #define PKGLIB_ACQUIRE_H
  34
  35 #include <vector>
  36 #include <string>
  37
  38 #ifdef __GNUG__
  39 #pragma interface "apt-pkg/acquire.h"
  40 #endif
  41
  42 #include <unistd.h>
  43
  44 class pkgAcquire
  45 {
  46    public:
  47
  48    class Item;
  49    class Queue;
  50    class Worker;
  51    struct MethodConfig;
  52    friend Item;
  53    friend Queue;
  54
  55    protected:
  56
  57    // List of items to fetch
  58    vector<Item *> Items;
  59
  60    // List of active queues and fetched method configuration parameters
  61    Queue *Queues;
  62    Worker *Workers;
  63    MethodConfig *Configs;
  64    unsigned long ToFetch;
  65
  66    // Configurable parameters for the schedular
  67    enum {QueueHost,QueueAccess} QueueMode;
  68    bool Debug;
  69
  70    void Add(Item *Item);
  71    void Remove(Item *Item);
  72    void Add(Worker *Work);
  73    void Remove(Worker *Work);
  74
  75    void Enqueue(Item *Item,string URI,string Description);
  76    void Dequeue(Item *Item);
  77    string QueueName(string URI);
  78
  79    // FDSET managers for derived classes
  80    void SetFds(int &Fd,fd_set *RSet,fd_set *WSet);
  81    void RunFds(fd_set *RSet,fd_set *WSet);
  82
  83    public:
  84
  85    MethodConfig *GetConfig(string Access);
  86    bool Run();
  87
  88    pkgAcquire();
  89    ~pkgAcquire();
  90 };
  91
  92 // List of possible items queued for download.
  93 class pkgAcquire::Queue
  94 {
  95    friend pkgAcquire;
  96    Queue *Next;
  97
  98    protected:
  99
 100    // Queued item
 101    struct QItem
 102    {
 103       QItem *Next;
 104
 105       string URI;
 106       string Description;
 107       Item *Owner;
 108       pkgAcquire::Worker *Worker;
 109    };
 110
 111    // Name of the queue
 112    string Name;
 113
 114    // Items queued into this queue
 115    QItem *Items;
 116    pkgAcquire::Worker *Workers;
 117    pkgAcquire *Owner;
 118
 119    public:
 120
 121    // Put an item into this queue
 122    void Enqueue(Item *Owner,string URI,string Description);
 123    void Dequeue(Item *Owner);
 124
 125    // Find a Queued item
 126    QItem *FindItem(string URI,pkgAcquire::Worker *Owner);
 127    bool ItemDone(QItem *Itm);
 128
 129    bool Startup();
 130    bool Shutdown();
 131
 132    Queue(string Name,pkgAcquire *Owner);
 133    ~Queue();
 134 };
 135
 136 // Configuration information from each method
 137 struct pkgAcquire::MethodConfig
 138 {
 139    MethodConfig *Next;
 140
 141    string Access;
 142
 143    string Version;
 144    bool SingleInstance;
 145    bool PreScan;
 146    bool Pipeline;
 147    bool SendConfig;
 148
 149    MethodConfig();
 150 };
 151
 152 #endif