summaryrefslogtreecommitdiff
path: root/apt-pkg/acquire.cc
blob: 2b427ccd347f10da9f8fc7a0c9694097a669ed16 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
// -*- mode: cpp; mode: fold -*-
// Description								/*{{{*/
// $Id: acquire.cc,v 1.50 2004/03/17 05:17:11 mdz Exp $
/* ######################################################################

   Acquire - File Acquiration

   The core element for the schedule system is the concept of a named
   queue. Each queue is unique and each queue has a name derived from the
   URI. The degree of paralization can be controlled by how the queue
   name is derived from the URI.
   
   ##################################################################### */
									/*}}}*/
// Include Files							/*{{{*/
#include <config.h>

#include <apt-pkg/acquire.h>
#include <apt-pkg/acquire-item.h>
#include <apt-pkg/acquire-worker.h>
#include <apt-pkg/configuration.h>
#include <apt-pkg/error.h>
#include <apt-pkg/strutl.h>
#include <apt-pkg/fileutl.h>

#include <string>
#include <vector>
#include <iostream>
#include <sstream>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <dirent.h>
#include <sys/time.h>
#include <sys/select.h>
#include <errno.h>

#include <apti18n.h>
									/*}}}*/

using namespace std;

// Acquire::pkgAcquire - Constructor					/*{{{*/
// ---------------------------------------------------------------------
/* We grab some runtime state from the configuration space */
pkgAcquire::pkgAcquire() : LockFD(-1), Queues(0), Workers(0), Configs(0), Log(NULL), ToFetch(0),
			   Debug(_config->FindB("Debug::pkgAcquire",false)),
			   Running(false)
{
   string const Mode = _config->Find("Acquire::Queue-Mode","host");
   if (strcasecmp(Mode.c_str(),"host") == 0)
      QueueMode = QueueHost;
   if (strcasecmp(Mode.c_str(),"access") == 0)
      QueueMode = QueueAccess;
}
pkgAcquire::pkgAcquire(pkgAcquireStatus *Progress) :  LockFD(-1), Queues(0), Workers(0),
			   Configs(0), Log(Progress), ToFetch(0),
			   Debug(_config->FindB("Debug::pkgAcquire",false)),
			   Running(false)
{
   string const Mode = _config->Find("Acquire::Queue-Mode","host");
   if (strcasecmp(Mode.c_str(),"host") == 0)
      QueueMode = QueueHost;
   if (strcasecmp(Mode.c_str(),"access") == 0)
      QueueMode = QueueAccess;
   Setup(Progress, "");
}
									/*}}}*/
// Acquire::Setup - Delayed Constructor					/*{{{*/
// ---------------------------------------------------------------------
/* Do everything needed to be a complete Acquire object and report the
   success (or failure) back so the user knows that something is wrong… */
bool pkgAcquire::Setup(pkgAcquireStatus *Progress, string const &Lock)
{
   Log = Progress;

   // check for existence and possibly create auxiliary directories
   string const listDir = _config->FindDir("Dir::State::lists");
   string const partialListDir = listDir + "partial/";
   string const archivesDir = _config->FindDir("Dir::Cache::Archives");
   string const partialArchivesDir = archivesDir + "partial/";

   if (CreateAPTDirectoryIfNeeded(_config->FindDir("Dir::State"), partialListDir) == false &&
       CreateAPTDirectoryIfNeeded(listDir, partialListDir) == false)
      return _error->Errno("Acquire", _("List directory %spartial is missing."), listDir.c_str());

   if (CreateAPTDirectoryIfNeeded(_config->FindDir("Dir::Cache"), partialArchivesDir) == false &&
       CreateAPTDirectoryIfNeeded(archivesDir, partialArchivesDir) == false)
      return _error->Errno("Acquire", _("Archives directory %spartial is missing."), archivesDir.c_str());

   if (Lock.empty() == true || _config->FindB("Debug::NoLocking", false) == true)
      return true;

   // Lock the directory this acquire object will work in
   LockFD = GetLock(flCombine(Lock, "lock"));
   if (LockFD == -1)
      return _error->Error(_("Unable to lock directory %s"), Lock.c_str());

   return true;
}
									/*}}}*/
// Acquire::~pkgAcquire	- Destructor					/*{{{*/
// ---------------------------------------------------------------------
/* Free our memory, clean up the queues (destroy the workers) */
pkgAcquire::~pkgAcquire()
{
   Shutdown();

   if (LockFD != -1)
      close(LockFD);

   while (Configs != 0)
   {
      MethodConfig *Jnk = Configs;
      Configs = Configs->Next;
      delete Jnk;
   }   
}
									/*}}}*/
// Acquire::Shutdown - Clean out the acquire object			/*{{{*/
// ---------------------------------------------------------------------
/* */
void pkgAcquire::Shutdown()
{
   while (Items.empty() == false)
   {
      if (Items[0]->Status == Item::StatFetching)
         Items[0]->Status = Item::StatError;
      delete Items[0];
   }

   while (Queues != 0)
   {
      Queue *Jnk = Queues;
      Queues = Queues->Next;
      delete Jnk;
   }   
}
									/*}}}*/
// Acquire::Add - Add a new item					/*{{{*/
// ---------------------------------------------------------------------
/* This puts an item on the acquire list. This list is mainly for tracking
   item status */
void pkgAcquire::Add(Item *Itm)
{
   Items.push_back(Itm);
}
									/*}}}*/
// Acquire::Remove - Remove a item					/*{{{*/
// ---------------------------------------------------------------------
/* Remove an item from the acquire list. This is usually not used.. */
void pkgAcquire::Remove(Item *Itm)
{
   Dequeue(Itm);
   
   for (ItemIterator I = Items.begin(); I != Items.end();)
   {
      if (*I == Itm)
      {
	 Items.erase(I);
	 I = Items.begin();
      }      
      else 
	 ++I;
   }
}
									/*}}}*/
// Acquire::Add - Add a worker						/*{{{*/
// ---------------------------------------------------------------------
/* A list of workers is kept so that the select loop can direct their FD
   usage. */
void pkgAcquire::Add(Worker *Work)
{
   Work->NextAcquire = Workers;
   Workers = Work;
}
									/*}}}*/
// Acquire::Remove - Remove a worker					/*{{{*/
// ---------------------------------------------------------------------
/* A worker has died. This can not be done while the select loop is running
   as it would require that RunFds could handling a changing list state and
   it can't.. */
void pkgAcquire::Remove(Worker *Work)
{
   if (Running == true)
      abort();
   
   Worker **I = &Workers;
   for (; *I != 0;)
   {
      if (*I == Work)
	 *I = (*I)->NextAcquire;
      else
	 I = &(*I)->NextAcquire;
   }
}
									/*}}}*/
// Acquire::Enqueue - Queue an URI for fetching				/*{{{*/
// ---------------------------------------------------------------------
/* This is the entry point for an item. An item calls this function when
   it is constructed which creates a queue (based on the current queue
   mode) and puts the item in that queue. If the system is running then
   the queue might be started. */
void pkgAcquire::Enqueue(ItemDesc &Item)
{
   // Determine which queue to put the item in
   const MethodConfig *Config;
   string Name = QueueName(Item.URI,Config);
   if (Name.empty() == true)
      return;

   // Find the queue structure
   Queue *I = Queues;
   for (; I != 0 && I->Name != Name; I = I->Next);
   if (I == 0)
   {
      I = new Queue(Name,this);
      I->Next = Queues;
      Queues = I;
      
      if (Running == true)
	 I->Startup();
   }

   // See if this is a local only URI
   if (Config->LocalOnly == true && Item.Owner->Complete == false)
      Item.Owner->Local = true;
   Item.Owner->Status = Item::StatIdle;
   
   // Queue it into the named queue
   if(I->Enqueue(Item)) 
      ToFetch++;
            
   // Some trace stuff
   if (Debug == true)
   {
      clog << "Fetching " << Item.URI << endl;
      clog << " to " << Item.Owner->DestFile << endl;
      clog << " Queue is: " << Name << endl;
   }
}
									/*}}}*/
// Acquire::Dequeue - Remove an item from all queues			/*{{{*/
// ---------------------------------------------------------------------
/* This is called when an item is finished being fetched. It removes it
   from all the queues */
void pkgAcquire::Dequeue(Item *Itm)
{
   Queue *I = Queues;
   bool Res = false;
   if (Debug == true)
      clog << "Dequeuing " << Itm->DestFile << endl;

   for (; I != 0; I = I->Next)
   {
      if (I->Dequeue(Itm))
      {
         Res = true;
	 if (Debug == true)
	    clog << "Dequeued from " << I->Name << endl;
      }
   }

   if (Res == true)
      ToFetch--;
}
									/*}}}*/
// Acquire::QueueName - Return the name of the queue for this URI	/*{{{*/
// ---------------------------------------------------------------------
/* The string returned depends on the configuration settings and the
   method parameters. Given something like http://foo.org/bar it can
   return http://foo.org or http */
string pkgAcquire::QueueName(string Uri,MethodConfig const *&Config)
{
   URI U(Uri);
   
   Config = GetConfig(U.Access);
   if (Config == 0)
      return string();
   
   /* Single-Instance methods get exactly one queue per URI. This is
      also used for the Access queue method  */
   if (Config->SingleInstance == true || QueueMode == QueueAccess)
      return U.Access;

   string AccessSchema = U.Access + ':',
	FullQueueName = AccessSchema + U.Host;
   unsigned int Instances = 0, SchemaLength = AccessSchema.length();

   Queue *I = Queues;
   for (; I != 0; I = I->Next) {
      // if the queue already exists, re-use it
      if (I->Name == FullQueueName)
	 return FullQueueName;

      if (I->Name.compare(0, SchemaLength, AccessSchema) == 0)
	 Instances++;
   }

   if (Debug) {
      clog << "Found " << Instances << " instances of " << U.Access << endl;
   }

   if (Instances >= (unsigned int)_config->FindI("Acquire::QueueHost::Limit",10))
      return U.Access;

   return FullQueueName;
}
									/*}}}*/
// Acquire::GetConfig - Fetch the configuration information		/*{{{*/
// ---------------------------------------------------------------------
/* This locates the configuration structure for an access method. If 
   a config structure cannot be found a Worker will be created to
   retrieve it */
pkgAcquire::MethodConfig *pkgAcquire::GetConfig(string Access)
{
   // Search for an existing config
   MethodConfig *Conf;
   for (Conf = Configs; Conf != 0; Conf = Conf->Next)
      if (Conf->Access == Access)
	 return Conf;
   
   // Create the new config class
   Conf = new MethodConfig;
   Conf->Access = Access;
   Conf->Next = Configs;
   Configs = Conf;

   // Create the worker to fetch the configuration
   Worker Work(Conf);
   if (Work.Start() == false)
      return 0;

   /* if a method uses DownloadLimit, we switch to SingleInstance mode */
   if(_config->FindI("Acquire::"+Access+"::Dl-Limit",0) > 0)
      Conf->SingleInstance = true;
    
   return Conf;
}
									/*}}}*/
// Acquire::SetFds - Deal with readable FDs				/*{{{*/
// ---------------------------------------------------------------------
/* Collect FDs that have activity monitors into the fd sets */
void pkgAcquire::SetFds(int &Fd,fd_set *RSet,fd_set *WSet)
{
   for (Worker *I = Workers; I != 0; I = I->NextAcquire)
   {
      if (I->InReady == true && I->InFd >= 0)
      {
	 if (Fd < I->InFd)
	    Fd = I->InFd;
	 FD_SET(I->InFd,RSet);
      }
      if (I->OutReady == true && I->OutFd >= 0)
      {
	 if (Fd < I->OutFd)
	    Fd = I->OutFd;
	 FD_SET(I->OutFd,WSet);
      }
   }
}
									/*}}}*/
// Acquire::RunFds - Deal with active FDs				/*{{{*/
// ---------------------------------------------------------------------
/* Dispatch active FDs over to the proper workers. It is very important
   that a worker never be erased while this is running! The queue class
   should never erase a worker except during shutdown processing. */
void pkgAcquire::RunFds(fd_set *RSet,fd_set *WSet)
{
   for (Worker *I = Workers; I != 0; I = I->NextAcquire)
   {
      if (I->InFd >= 0 && FD_ISSET(I->InFd,RSet) != 0)
	 I->InFdReady();
      if (I->OutFd >= 0 && FD_ISSET(I->OutFd,WSet) != 0)
	 I->OutFdReady();
   }
}
									/*}}}*/
// Acquire::Run - Run the fetch sequence				/*{{{*/
// ---------------------------------------------------------------------
/* This runs the queues. It manages a select loop for all of the
   Worker tasks. The workers interact with the queues and items to
   manage the actual fetch. */
pkgAcquire::RunResult pkgAcquire::Run(int PulseIntervall)
{
   Running = true;
   
   for (Queue *I = Queues; I != 0; I = I->Next)
      I->Startup();
   
   if (Log != 0)
      Log->Start();
   
   bool WasCancelled = false;

   // Run till all things have been acquired
   struct timeval tv;
   tv.tv_sec = 0;
   tv.tv_usec = PulseIntervall; 
   while (ToFetch > 0)
   {
      fd_set RFds;
      fd_set WFds;
      int Highest = 0;
      FD_ZERO(&RFds);
      FD_ZERO(&WFds);
      SetFds(Highest,&RFds,&WFds);
      
      int Res;
      do
      {
	 Res = select(Highest+1,&RFds,&WFds,0,&tv);
      }
      while (Res < 0 && errno == EINTR);
      
      if (Res < 0)
      {
	 _error->Errno("select","Select has failed");
	 break;
      }
	     
      RunFds(&RFds,&WFds);
      if (_error->PendingError() == true)
	 break;
      
      // Timeout, notify the log class
      if (Res == 0 || (Log != 0 && Log->Update == true))
      {
	 tv.tv_usec = PulseIntervall;
	 for (Worker *I = Workers; I != 0; I = I->NextAcquire)
	    I->Pulse();
	 if (Log != 0 && Log->Pulse(this) == false)
	 {
	    WasCancelled = true;
	    break;
	 }
      }      
   }   

   if (Log != 0)
      Log->Stop();
   
   // Shut down the acquire bits
   Running = false;
   for (Queue *I = Queues; I != 0; I = I->Next)
      I->Shutdown(false);

   // Shut down the items
   for (ItemIterator I = Items.begin(); I != Items.end(); ++I)
      (*I)->Finished(); 
   
   if (_error->PendingError())
      return Failed;
   if (WasCancelled)
      return Cancelled;
   return Continue;
}
									/*}}}*/
// Acquire::Bump - Called when an item is dequeued			/*{{{*/
// ---------------------------------------------------------------------
/* This routine bumps idle queues in hopes that they will be able to fetch
   the dequeued item */
void pkgAcquire::Bump()
{
   for (Queue *I = Queues; I != 0; I = I->Next)
      I->Bump();
}
									/*}}}*/
// Acquire::WorkerStep - Step to the next worker			/*{{{*/
// ---------------------------------------------------------------------
/* Not inlined to advoid including acquire-worker.h */
pkgAcquire::Worker *pkgAcquire::WorkerStep(Worker *I)
{
   return I->NextAcquire;
}
									/*}}}*/
// Acquire::Clean - Cleans a directory					/*{{{*/
// ---------------------------------------------------------------------
/* This is a bit simplistic, it looks at every file in the dir and sees
   if it is part of the download set. */
bool pkgAcquire::Clean(string Dir)
{
   // non-existing directories are by definition clean…
   if (DirectoryExists(Dir) == false)
      return true;

   DIR *D = opendir(Dir.c_str());   
   if (D == 0)
      return _error->Errno("opendir",_("Unable to read %s"),Dir.c_str());
   
   string StartDir = SafeGetCWD();
   if (chdir(Dir.c_str()) != 0)
   {
      closedir(D);
      return _error->Errno("chdir",_("Unable to change to %s"),Dir.c_str());
   }
   
   for (struct dirent *Dir = readdir(D); Dir != 0; Dir = readdir(D))
   {
      // Skip some files..
      if (strcmp(Dir->d_name,"lock") == 0 ||
	  strcmp(Dir->d_name,"partial") == 0 ||
	  strcmp(Dir->d_name,".") == 0 ||
	  strcmp(Dir->d_name,"..") == 0)
	 continue;
      
      // Look in the get list
      ItemCIterator I = Items.begin();
      for (; I != Items.end(); ++I)
	 if (flNotDir((*I)->DestFile) == Dir->d_name)
	    break;
      
      // Nothing found, nuke it
      if (I == Items.end())
	 unlink(Dir->d_name);
   };
   
   closedir(D);
   if (chdir(StartDir.c_str()) != 0)
      return _error->Errno("chdir",_("Unable to change to %s"),StartDir.c_str());
   return true;   
}
									/*}}}*/
// Acquire::TotalNeeded - Number of bytes to fetch			/*{{{*/
// ---------------------------------------------------------------------
/* This is the total number of bytes needed */
APT_PURE unsigned long long pkgAcquire::TotalNeeded()
{
   unsigned long long Total = 0;
   for (ItemCIterator I = ItemsBegin(); I != ItemsEnd(); ++I)
      Total += (*I)->FileSize;
   return Total;
}
									/*}}}*/
// Acquire::FetchNeeded - Number of bytes needed to get			/*{{{*/
// ---------------------------------------------------------------------
/* This is the number of bytes that is not local */
APT_PURE unsigned long long pkgAcquire::FetchNeeded()
{
   unsigned long long Total = 0;
   for (ItemCIterator I = ItemsBegin(); I != ItemsEnd(); ++I)
      if ((*I)->Local == false)
	 Total += (*I)->FileSize;
   return Total;
}
									/*}}}*/
// Acquire::PartialPresent - Number of partial bytes we already have	/*{{{*/
// ---------------------------------------------------------------------
/* This is the number of bytes that is not local */
APT_PURE unsigned long long pkgAcquire::PartialPresent()
{
  unsigned long long Total = 0;
   for (ItemCIterator I = ItemsBegin(); I != ItemsEnd(); ++I)
      if ((*I)->Local == false)
	 Total += (*I)->PartialSize;
   return Total;
}
									/*}}}*/
// Acquire::UriBegin - Start iterator for the uri list			/*{{{*/
// ---------------------------------------------------------------------
/* */
pkgAcquire::UriIterator pkgAcquire::UriBegin()
{
   return UriIterator(Queues);
}
									/*}}}*/
// Acquire::UriEnd - End iterator for the uri list			/*{{{*/
// ---------------------------------------------------------------------
/* */
pkgAcquire::UriIterator pkgAcquire::UriEnd()
{
   return UriIterator(0);
}
									/*}}}*/
// Acquire::MethodConfig::MethodConfig - Constructor			/*{{{*/
// ---------------------------------------------------------------------
/* */
pkgAcquire::MethodConfig::MethodConfig()
{
   SingleInstance = false;
   Pipeline = false;
   SendConfig = false;
   LocalOnly = false;
   Removable = false;
   Next = 0;
}
									/*}}}*/
// Queue::Queue - Constructor						/*{{{*/
// ---------------------------------------------------------------------
/* */
pkgAcquire::Queue::Queue(string Name,pkgAcquire *Owner) : Name(Name), 
            Owner(Owner)
{
   Items = 0;
   Next = 0;
   Workers = 0;
   MaxPipeDepth = 1;
   PipeDepth = 0;
}
									/*}}}*/
// Queue::~Queue - Destructor						/*{{{*/
// ---------------------------------------------------------------------
/* */
pkgAcquire::Queue::~Queue()
{
   Shutdown(true);
   
   while (Items != 0)
   {
      QItem *Jnk = Items;
      Items = Items->Next;
      delete Jnk;
   }
}
									/*}}}*/
// Queue::Enqueue - Queue an item to the queue				/*{{{*/
// ---------------------------------------------------------------------
/* */
bool pkgAcquire::Queue::Enqueue(ItemDesc &Item)
{
   QItem **I = &Items;
   // move to the end of the queue and check for duplicates here
   for (; *I != 0; I = &(*I)->Next)
      if (Item.URI == (*I)->URI) 
      {
	 Item.Owner->Status = Item::StatDone;
	 return false;
      }

   // Create a new item
   QItem *Itm = new QItem;
   *Itm = Item;
   Itm->Next = 0;
   *I = Itm;
   
   Item.Owner->QueueCounter++;   
   if (Items->Next == 0)
      Cycle();
   return true;
}
									/*}}}*/
// Queue::Dequeue - Remove an item from the queue			/*{{{*/
// ---------------------------------------------------------------------
/* We return true if we hit something */
bool pkgAcquire::Queue::Dequeue(Item *Owner)
{
   if (Owner->Status == pkgAcquire::Item::StatFetching)
      return _error->Error("Tried to dequeue a fetching object");
       
   bool Res = false;
   
   QItem **I = &Items;
   for (; *I != 0;)
   {
      if ((*I)->Owner == Owner)
      {
	 QItem *Jnk= *I;
	 *I = (*I)->Next;
	 Owner->QueueCounter--;
	 delete Jnk;
	 Res = true;
      }
      else
	 I = &(*I)->Next;
   }
   
   return Res;
}
									/*}}}*/
// Queue::Startup - Start the worker processes				/*{{{*/
// ---------------------------------------------------------------------
/* It is possible for this to be called with a pre-existing set of
   workers. */
bool pkgAcquire::Queue::Startup()
{
   if (Workers == 0)
   {
      URI U(Name);
      pkgAcquire::MethodConfig *Cnf = Owner->GetConfig(U.Access);
      if (Cnf == 0)
	 return false;
      
      Workers = new Worker(this,Cnf,Owner->Log);
      Owner->Add(Workers);
      if (Workers->Start() == false)
	 return false;
      
      /* When pipelining we commit 10 items. This needs to change when we
         added other source retry to have cycle maintain a pipeline depth
         on its own. */
      if (Cnf->Pipeline == true)
	 MaxPipeDepth = _config->FindI("Acquire::Max-Pipeline-Depth",10);
      else
	 MaxPipeDepth = 1;
   }
   
   return Cycle();
}
									/*}}}*/
// Queue::Shutdown - Shutdown the worker processes			/*{{{*/
// ---------------------------------------------------------------------
/* If final is true then all workers are eliminated, otherwise only workers
   that do not need cleanup are removed */
bool pkgAcquire::Queue::Shutdown(bool Final)
{
   // Delete all of the workers
   pkgAcquire::Worker **Cur = &Workers;
   while (*Cur != 0)
   {
      pkgAcquire::Worker *Jnk = *Cur;
      if (Final == true || Jnk->GetConf()->NeedsCleanup == false)
      {
	 *Cur = Jnk->NextQueue;
	 Owner->Remove(Jnk);
	 delete Jnk;
      }
      else
	 Cur = &(*Cur)->NextQueue;      
   }
   
   return true;
}
									/*}}}*/
// Queue::FindItem - Find a URI in the item list			/*{{{*/
// ---------------------------------------------------------------------
/* */
pkgAcquire::Queue::QItem *pkgAcquire::Queue::FindItem(string URI,pkgAcquire::Worker *Owner)
{
   for (QItem *I = Items; I != 0; I = I->Next)
      if (I->URI == URI && I->Worker == Owner)
	 return I;
   return 0;
}
									/*}}}*/
// Queue::ItemDone - Item has been completed				/*{{{*/
// ---------------------------------------------------------------------
/* The worker signals this which causes the item to be removed from the
   queue. If this is the last queue instance then it is removed from the
   main queue too.*/
bool pkgAcquire::Queue::ItemDone(QItem *Itm)
{
   PipeDepth--;
   if (Itm->Owner->Status == pkgAcquire::Item::StatFetching)
      Itm->Owner->Status = pkgAcquire::Item::StatDone;
   
   if (Itm->Owner->QueueCounter <= 1)
      Owner->Dequeue(Itm->Owner);
   else
   {
      Dequeue(Itm->Owner);
      Owner->Bump();
   }
   
   return Cycle();
}
									/*}}}*/
// Queue::Cycle - Queue new items into the method			/*{{{*/
// ---------------------------------------------------------------------
/* This locates a new idle item and sends it to the worker. If pipelining
   is enabled then it keeps the pipe full. */
bool pkgAcquire::Queue::Cycle()
{
   if (Items == 0 || Workers == 0)
      return true;

   if (PipeDepth < 0)
      return _error->Error("Pipedepth failure");
			   
   // Look for a queable item
   QItem *I = Items;
   while (PipeDepth < (signed)MaxPipeDepth)
   {
      for (; I != 0; I = I->Next)
	 if (I->Owner->Status == pkgAcquire::Item::StatIdle)
	    break;
      
      // Nothing to do, queue is idle.
      if (I == 0)
	 return true;
      
      I->Worker = Workers;
      I->Owner->Status = pkgAcquire::Item::StatFetching;
      PipeDepth++;
      if (Workers->QueueItem(I) == false)
	 return false;
   }
   
   return true;
}
									/*}}}*/
// Queue::Bump - Fetch any pending objects if we are idle		/*{{{*/
// ---------------------------------------------------------------------
/* This is called when an item in multiple queues is dequeued */
void pkgAcquire::Queue::Bump()
{
   Cycle();
}
									/*}}}*/
// AcquireStatus::pkgAcquireStatus - Constructor			/*{{{*/
// ---------------------------------------------------------------------
/* */
pkgAcquireStatus::pkgAcquireStatus() : d(NULL), Update(true), MorePulses(false)
{
   Start();
}
									/*}}}*/
// AcquireStatus::Pulse - Called periodically				/*{{{*/
// ---------------------------------------------------------------------
/* This computes some internal state variables for the derived classes to
   use. It generates the current downloaded bytes and total bytes to download
   as well as the current CPS estimate. */
bool pkgAcquireStatus::Pulse(pkgAcquire *Owner)
{
   TotalBytes = 0;
   CurrentBytes = 0;
   TotalItems = 0;
   CurrentItems = 0;
   
   // Compute the total number of bytes to fetch
   unsigned int Unknown = 0;
   unsigned int Count = 0;
   for (pkgAcquire::ItemCIterator I = Owner->ItemsBegin(); I != Owner->ItemsEnd();
	++I, ++Count)
   {
      TotalItems++;
      if ((*I)->Status == pkgAcquire::Item::StatDone)
	 ++CurrentItems;
      
      // Totally ignore local items
      if ((*I)->Local == true)
	 continue;

      // see if the method tells us to expect more
      TotalItems += (*I)->ExpectedAdditionalItems;

      TotalBytes += (*I)->FileSize;
      if ((*I)->Complete == true)
	 CurrentBytes += (*I)->FileSize;
      if ((*I)->FileSize == 0 && (*I)->Complete == false)
	 ++Unknown;
   }
   
   // Compute the current completion
   unsigned long long ResumeSize = 0;
   for (pkgAcquire::Worker *I = Owner->WorkersBegin(); I != 0;
	I = Owner->WorkerStep(I))
      if (I->CurrentItem != 0 && I->CurrentItem->Owner->Complete == false)
      {
	 CurrentBytes += I->CurrentSize;
	 ResumeSize += I->ResumePoint;
	 
	 // Files with unknown size always have 100% completion
	 if (I->CurrentItem->Owner->FileSize == 0 && 
	     I->CurrentItem->Owner->Complete == false)
	    TotalBytes += I->CurrentSize;
      }
   
   // Normalize the figures and account for unknown size downloads
   if (TotalBytes <= 0)
      TotalBytes = 1;
   if (Unknown == Count)
      TotalBytes = Unknown;

   // Wha?! Is not supposed to happen.
   if (CurrentBytes > TotalBytes)
      CurrentBytes = TotalBytes;
   
   // Compute the CPS
   struct timeval NewTime;
   gettimeofday(&NewTime,0);
   if ((NewTime.tv_sec - Time.tv_sec == 6 && NewTime.tv_usec > Time.tv_usec) ||
       NewTime.tv_sec - Time.tv_sec > 6)
   {    
      double Delta = NewTime.tv_sec - Time.tv_sec + 
	             (NewTime.tv_usec - Time.tv_usec)/1000000.0;
      
      // Compute the CPS value
      if (Delta < 0.01)
	 CurrentCPS = 0;
      else
	 CurrentCPS = ((CurrentBytes - ResumeSize) - LastBytes)/Delta;
      LastBytes = CurrentBytes - ResumeSize;
      ElapsedTime = (unsigned long long)Delta;
      Time = NewTime;
   }

   int fd = _config->FindI("APT::Status-Fd",-1);
   if(fd > 0) 
   {
      ostringstream status;

      char msg[200];
      long i = CurrentItems < TotalItems ? CurrentItems + 1 : CurrentItems;
      unsigned long long ETA = 0;
      if(CurrentCPS > 0)
         ETA = (TotalBytes - CurrentBytes) / CurrentCPS;

      // only show the ETA if it makes sense
      if (ETA > 0 && ETA < 172800 /* two days */ )
	 snprintf(msg,sizeof(msg), _("Retrieving file %li of %li (%s remaining)"), i, TotalItems, TimeToStr(ETA).c_str());
      else
	 snprintf(msg,sizeof(msg), _("Retrieving file %li of %li"), i, TotalItems);
	 

      // calculate the percentage, if we have too little data assume 0%
      int Percent;
      if (TotalBytes < 1*1024)
         Percent = 0;
      else
         Percent = (CurrentBytes/float(TotalBytes)*100.0);
      // build the status str
      status << "dlstatus:" << i
             << ":"  << Percent
             << ":" << msg 
             << endl;

      std::string const dlstatus = status.str();
      FileFd::Write(fd, dlstatus.c_str(), dlstatus.size());
   }

   return true;
}
									/*}}}*/
// AcquireStatus::Start - Called when the download is started		/*{{{*/
// ---------------------------------------------------------------------
/* We just reset the counters */
void pkgAcquireStatus::Start()
{
   gettimeofday(&Time,0);
   gettimeofday(&StartTime,0);
   LastBytes = 0;
   CurrentCPS = 0;
   CurrentBytes = 0;
   TotalBytes = 0;
   FetchedBytes = 0;
   ElapsedTime = 0;
   TotalItems = 0;
   CurrentItems = 0;
}
									/*}}}*/
// AcquireStatus::Stop - Finished downloading				/*{{{*/
// ---------------------------------------------------------------------
/* This accurately computes the elapsed time and the total overall CPS. */
void pkgAcquireStatus::Stop()
{
   // Compute the CPS and elapsed time
   struct timeval NewTime;
   gettimeofday(&NewTime,0);
   
   double Delta = NewTime.tv_sec - StartTime.tv_sec + 
                  (NewTime.tv_usec - StartTime.tv_usec)/1000000.0;
   
   // Compute the CPS value
   if (Delta < 0.01)
      CurrentCPS = 0;
   else
      CurrentCPS = FetchedBytes/Delta;
   LastBytes = CurrentBytes;
   ElapsedTime = (unsigned long long)Delta;
}
									/*}}}*/
// AcquireStatus::Fetched - Called when a byte set has been fetched	/*{{{*/
// ---------------------------------------------------------------------
/* This is used to get accurate final transfer rate reporting. */
void pkgAcquireStatus::Fetched(unsigned long long Size,unsigned long long Resume)
{   
   FetchedBytes += Size - Resume;
}
									/*}}}*/