apt-pkg/acquire.h

   1 // -*- mode: cpp; mode: fold -*-
   2 // Description                                                          /*{{{*/
   3 // $Id: acquire.h,v 1.3 1998/10/22 04:56:44 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    };
 109
 110    // Name of the queue
 111    string Name;
 112
 113    // Items queued into this queue
 114    QItem *Items;
 115    pkgAcquire::Worker *Workers;
 116    pkgAcquire *Owner;
 117
 118    public:
 119
 120    // Put an item into this queue
 121    void Enqueue(Item *Owner,string URI,string Description);
 122    void Dequeue(Item *Owner);
 123
 124    bool Startup();
 125    bool Shutdown();
 126
 127    Queue(string Name,pkgAcquire *Owner);
 128    ~Queue();
 129 };
 130
 131 // Configuration information from each method
 132 struct pkgAcquire::MethodConfig
 133 {
 134    MethodConfig *Next;
 135
 136    string Access;
 137
 138    string Version;
 139    bool SingleInstance;
 140    bool PreScan;
 141    bool Pipeline;
 142    bool SendConfig;
 143
 144    MethodConfig();
 145 };
 146
 147 #endif