apt-pkg/acquire.h

   1 // -*- mode: cpp; mode: fold -*-
   2 // Description                                                          /*{{{*/
   3 // $Id: acquire.h,v 1.5 1998/10/26 07:11:48 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    bool Running;
  70
  71    void Add(Item *Item);
  72    void Remove(Item *Item);
  73    void Add(Worker *Work);
  74    void Remove(Worker *Work);
  75
  76    void Enqueue(Item *Item,string URI,string Description);
  77    void Dequeue(Item *Item);
  78    string QueueName(string URI);
  79
  80    // FDSET managers for derived classes
  81    void SetFds(int &Fd,fd_set *RSet,fd_set *WSet);
  82    void RunFds(fd_set *RSet,fd_set *WSet);
  83
  84    public:
  85
  86    MethodConfig *GetConfig(string Access);
  87    bool Run();
  88
  89    pkgAcquire();
  90    ~pkgAcquire();
  91 };
  92
  93 // List of possible items queued for download.
  94 class pkgAcquire::Queue
  95 {
  96    friend pkgAcquire;
  97    Queue *Next;
  98
  99    protected:
 100
 101    // Queued item
 102    struct QItem
 103    {
 104       QItem *Next;
 105
 106       string URI;
 107       string Description;
 108       Item *Owner;
 109       pkgAcquire::Worker *Worker;
 110    };
 111
 112    // Name of the queue
 113    string Name;
 114
 115    // Items queued into this queue
 116    QItem *Items;
 117    pkgAcquire::Worker *Workers;
 118    pkgAcquire *Owner;
 119
 120    public:
 121
 122    // Put an item into this queue
 123    void Enqueue(Item *Owner,string URI,string Description);
 124    void Dequeue(Item *Owner);
 125
 126    // Find a Queued item
 127    QItem *FindItem(string URI,pkgAcquire::Worker *Owner);
 128    bool ItemDone(QItem *Itm);
 129
 130    bool Startup();
 131    bool Shutdown();
 132
 133    Queue(string Name,pkgAcquire *Owner);
 134    ~Queue();
 135 };
 136
 137 // Configuration information from each method
 138 struct pkgAcquire::MethodConfig
 139 {
 140    MethodConfig *Next;
 141
 142    string Access;
 143
 144    string Version;
 145    bool SingleInstance;
 146    bool PreScan;
 147    bool Pipeline;
 148    bool SendConfig;
 149
 150    MethodConfig();
 151 };
 152
 153 #endif