apt-pkg/acquire.h

   1 // -*- mode: cpp; mode: fold -*-
   2 // Description                                                          /*{{{*/
   3 // $Id: acquire.h,v 1.18 1998/12/11 07:20:33 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 <sys/time.h>
  43 #include <unistd.h>
  44
  45 class pkgAcquireStatus;
  46 class pkgAcquire
  47 {
  48    public:
  49
  50    class Item;
  51    class Queue;
  52    class Worker;
  53    struct MethodConfig;
  54    struct ItemDesc;
  55    friend Item;
  56    friend Queue;
  57
  58    protected:
  59
  60    // List of items to fetch
  61    vector<Item *> Items;
  62
  63    // List of active queues and fetched method configuration parameters
  64    Queue *Queues;
  65    Worker *Workers;
  66    MethodConfig *Configs;
  67    pkgAcquireStatus *Log;
  68    unsigned long ToFetch;
  69
  70    // Configurable parameters for the schedular
  71    enum {QueueHost,QueueAccess} QueueMode;
  72    bool Debug;
  73    bool Running;
  74
  75    void Add(Item *Item);
  76    void Remove(Item *Item);
  77    void Add(Worker *Work);
  78    void Remove(Worker *Work);
  79
  80    void Enqueue(ItemDesc &Item);
  81    void Dequeue(Item *Item);
  82    string QueueName(string URI,MethodConfig const *&Config);
  83
  84    // FDSET managers for derived classes
  85    void SetFds(int &Fd,fd_set *RSet,fd_set *WSet);
  86    void RunFds(fd_set *RSet,fd_set *WSet);
  87
  88    // A queue calls this when it dequeues an item
  89    void Bump();
  90
  91    public:
  92
  93    MethodConfig *GetConfig(string Access);
  94    bool Run();
  95
  96    // Simple iteration mechanism
  97    inline Worker *WorkersBegin() {return Workers;};
  98    Worker *WorkerStep(Worker *I);
  99    inline Item **ItemsBegin() {return Items.begin();};
 100    inline Item **ItemsEnd() {return Items.end();};
 101
 102    // Cleans out the download dir
 103    bool Clean(string Dir);
 104
 105    // Returns the size of the total download set
 106    unsigned long TotalNeeded();
 107    unsigned long FetchNeeded();
 108
 109    pkgAcquire(pkgAcquireStatus *Log = 0);
 110    ~pkgAcquire();
 111 };
 112
 113 // Description of an Item+URI
 114 struct pkgAcquire::ItemDesc
 115 {
 116    string URI;
 117    string Description;
 118    string ShortDesc;
 119    Item *Owner;
 120 };
 121
 122 // List of possible items queued for download.
 123 class pkgAcquire::Queue
 124 {
 125    friend pkgAcquire;
 126    Queue *Next;
 127
 128    protected:
 129
 130    // Queued item
 131    struct QItem : pkgAcquire::ItemDesc
 132    {
 133       QItem *Next;
 134       pkgAcquire::Worker *Worker;
 135
 136       void operator =(pkgAcquire::ItemDesc const &I)
 137       {
 138          URI = I.URI;
 139          Description = I.Description;
 140          ShortDesc = I.ShortDesc;
 141          Owner = I.Owner;
 142       };
 143    };
 144
 145    // Name of the queue
 146    string Name;
 147
 148    // Items queued into this queue
 149    QItem *Items;
 150    pkgAcquire::Worker *Workers;
 151    pkgAcquire *Owner;
 152    signed long PipeDepth;
 153    unsigned long MaxPipeDepth;
 154
 155    public:
 156
 157    // Put an item into this queue
 158    void Enqueue(ItemDesc &Item);
 159    bool Dequeue(Item *Owner);
 160
 161    // Find a Queued item
 162    QItem *FindItem(string URI,pkgAcquire::Worker *Owner);
 163    bool ItemStart(QItem *Itm,unsigned long Size);
 164    bool ItemDone(QItem *Itm);
 165
 166    bool Startup();
 167    bool Shutdown();
 168    bool Cycle();
 169    void Bump();
 170
 171    Queue(string Name,pkgAcquire *Owner);
 172    ~Queue();
 173 };
 174
 175 // Configuration information from each method
 176 struct pkgAcquire::MethodConfig
 177 {
 178    MethodConfig *Next;
 179
 180    string Access;
 181
 182    string Version;
 183    bool SingleInstance;
 184    bool Pipeline;
 185    bool SendConfig;
 186    bool LocalOnly;
 187
 188    MethodConfig();
 189 };
 190
 191 class pkgAcquireStatus
 192 {
 193    protected:
 194
 195    struct timeval Time;
 196    struct timeval StartTime;
 197    unsigned long LastBytes;
 198    double CurrentCPS;
 199    unsigned long CurrentBytes;
 200    unsigned long TotalBytes;
 201    unsigned long FetchedBytes;
 202    unsigned long ElapsedTime;
 203    unsigned long TotalItems;
 204    unsigned long CurrentItems;
 205
 206    public:
 207
 208    bool Update;
 209
 210    // Called by items when they have finished a real download
 211    virtual void Fetched(unsigned long Size,unsigned long ResumePoint);
 212
 213    // Called to change media
 214    virtual bool MediaChange(string Media,string Drive) = 0;
 215
 216    // Each of these is called by the workers when an event occures
 217    virtual void IMSHit(pkgAcquire::ItemDesc &Itm) {};
 218    virtual void Fetch(pkgAcquire::ItemDesc &Itm) {};
 219    virtual void Done(pkgAcquire::ItemDesc &Itm) {};
 220    virtual void Fail(pkgAcquire::ItemDesc &Itm) {};
 221    virtual void Pulse(pkgAcquire *Owner);
 222    virtual void Start();
 223    virtual void Stop();
 224
 225    pkgAcquireStatus();
 226    virtual ~pkgAcquireStatus() {};
 227 };
 228
 229 #endif