apt-pkg/acquire.h

   1 // -*- mode: cpp; mode: fold -*-
   2 // Description                                                          /*{{{*/
   3 // $Id: acquire.h,v 1.8 1998/11/05 07:21:41 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    // A queue calls this when it dequeues an item
  85    void Bump();
  86
  87    public:
  88
  89    MethodConfig *GetConfig(string Access);
  90    bool Run();
  91
  92    pkgAcquire();
  93    ~pkgAcquire();
  94 };
  95
  96 // List of possible items queued for download.
  97 class pkgAcquire::Queue
  98 {
  99    friend pkgAcquire;
 100    Queue *Next;
 101
 102    protected:
 103
 104    // Queued item
 105    struct QItem
 106    {
 107       QItem *Next;
 108
 109       string URI;
 110       string Description;
 111       Item *Owner;
 112       pkgAcquire::Worker *Worker;
 113    };
 114
 115    // Name of the queue
 116    string Name;
 117
 118    // Items queued into this queue
 119    QItem *Items;
 120    pkgAcquire::Worker *Workers;
 121    pkgAcquire *Owner;
 122
 123    public:
 124
 125    // Put an item into this queue
 126    void Enqueue(Item *Owner,string URI,string Description);
 127    bool Dequeue(Item *Owner);
 128
 129    // Find a Queued item
 130    QItem *FindItem(string URI,pkgAcquire::Worker *Owner);
 131    bool ItemDone(QItem *Itm);
 132
 133    bool Startup();
 134    bool Shutdown();
 135    bool Cycle();
 136    void Bump();
 137
 138    Queue(string Name,pkgAcquire *Owner);
 139    ~Queue();
 140 };
 141
 142 // Configuration information from each method
 143 struct pkgAcquire::MethodConfig
 144 {
 145    MethodConfig *Next;
 146
 147    string Access;
 148
 149    string Version;
 150    bool SingleInstance;
 151    bool PreScan;
 152    bool Pipeline;
 153    bool SendConfig;
 154
 155    MethodConfig();
 156 };
 157
 158 #endif