net/socket/client_socket_pool_base.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "net/socket/client_socket_pool_base.h"
   6
   7 #include "base/compiler_specific.h"
   8 #include "base/format_macros.h"
   9 #include "base/logging.h"
  10 #include "base/message_loop/message_loop.h"
  11 #include "base/profiler/scoped_tracker.h"
  12 #include "base/stl_util.h"
  13 #include "base/strings/string_util.h"
  14 #include "base/time/time.h"
  15 #include "base/values.h"
  16 #include "net/base/net_errors.h"
  17 #include "net/base/net_log.h"
  18
  19 using base::TimeDelta;
  20
  21 namespace net {
  22
  23 namespace {
  24
  25 // Indicate whether we should enable idle socket cleanup timer. When timer is
  26 // disabled, sockets are closed next time a socket request is made.
  27 bool g_cleanup_timer_enabled = true;
  28
  29 // The timeout value, in seconds, used to clean up idle sockets that can't be
  30 // reused.
  31 //
  32 // Note: It's important to close idle sockets that have received data as soon
  33 // as possible because the received data may cause BSOD on Windows XP under
  34 // some conditions.  See http://crbug.com/4606.
  35 const int kCleanupInterval = 10;  // DO NOT INCREASE THIS TIMEOUT.
  36
  37 // Indicate whether or not we should establish a new transport layer connection
  38 // after a certain timeout has passed without receiving an ACK.
  39 bool g_connect_backup_jobs_enabled = true;
  40
  41 }  // namespace
  42
  43 ConnectJob::ConnectJob(const std::string& group_name,
  44                        base::TimeDelta timeout_duration,
  45                        RequestPriority priority,
  46                        Delegate* delegate,
  47                        const BoundNetLog& net_log)
  48     : group_name_(group_name),
  49       timeout_duration_(timeout_duration),
  50       priority_(priority),
  51       delegate_(delegate),
  52       net_log_(net_log),
  53       idle_(true) {
  54   DCHECK(!group_name.empty());
  55   DCHECK(delegate);
  56   net_log.BeginEvent(NetLog::TYPE_SOCKET_POOL_CONNECT_JOB,
  57                      NetLog::StringCallback("group_name", &group_name_));
  58 }
  59
  60 ConnectJob::~ConnectJob() {
  61   net_log().EndEvent(NetLog::TYPE_SOCKET_POOL_CONNECT_JOB);
  62 }
  63
  64 scoped_ptr<StreamSocket> ConnectJob::PassSocket() {
  65   return socket_.Pass();
  66 }
  67
  68 int ConnectJob::Connect() {
  69   if (timeout_duration_ != base::TimeDelta())
  70     timer_.Start(FROM_HERE, timeout_duration_, this, &ConnectJob::OnTimeout);
  71
  72   idle_ = false;
  73
  74   LogConnectStart();
  75
  76   int rv = ConnectInternal();
  77
  78   if (rv != ERR_IO_PENDING) {
  79     LogConnectCompletion(rv);
  80     delegate_ = NULL;
  81   }
  82
  83   return rv;
  84 }
  85
  86 void ConnectJob::SetSocket(scoped_ptr<StreamSocket> socket) {
  87   if (socket) {
  88     net_log().AddEvent(NetLog::TYPE_CONNECT_JOB_SET_SOCKET,
  89                        socket->NetLog().source().ToEventParametersCallback());
  90   }
  91   socket_ = socket.Pass();
  92 }
  93
  94 void ConnectJob::NotifyDelegateOfCompletion(int rv) {
  95   // The delegate will own |this|.
  96   Delegate* delegate = delegate_;
  97   delegate_ = NULL;
  98
  99   LogConnectCompletion(rv);
 100   delegate->OnConnectJobComplete(rv, this);
 101 }
 102
 103 void ConnectJob::ResetTimer(base::TimeDelta remaining_time) {
 104   timer_.Stop();
 105   timer_.Start(FROM_HERE, remaining_time, this, &ConnectJob::OnTimeout);
 106 }
 107
 108 void ConnectJob::LogConnectStart() {
 109   connect_timing_.connect_start = base::TimeTicks::Now();
 110   net_log().BeginEvent(NetLog::TYPE_SOCKET_POOL_CONNECT_JOB_CONNECT);
 111 }
 112
 113 void ConnectJob::LogConnectCompletion(int net_error) {
 114   connect_timing_.connect_end = base::TimeTicks::Now();
 115   net_log().EndEventWithNetErrorCode(
 116       NetLog::TYPE_SOCKET_POOL_CONNECT_JOB_CONNECT, net_error);
 117 }
 118
 119 void ConnectJob::OnTimeout() {
 120   // Make sure the socket is NULL before calling into |delegate|.
 121   SetSocket(scoped_ptr<StreamSocket>());
 122
 123   net_log_.AddEvent(NetLog::TYPE_SOCKET_POOL_CONNECT_JOB_TIMED_OUT);
 124
 125   NotifyDelegateOfCompletion(ERR_TIMED_OUT);
 126 }
 127
 128 namespace internal {
 129
 130 ClientSocketPoolBaseHelper::Request::Request(
 131     ClientSocketHandle* handle,
 132     const CompletionCallback& callback,
 133     RequestPriority priority,
 134     bool ignore_limits,
 135     Flags flags,
 136     const BoundNetLog& net_log)
 137     : handle_(handle),
 138       callback_(callback),
 139       priority_(priority),
 140       ignore_limits_(ignore_limits),
 141       flags_(flags),
 142       net_log_(net_log) {
 143   if (ignore_limits_)
 144     DCHECK_EQ(priority_, MAXIMUM_PRIORITY);
 145 }
 146
 147 ClientSocketPoolBaseHelper::Request::~Request() {}
 148
 149 ClientSocketPoolBaseHelper::ClientSocketPoolBaseHelper(
 150     HigherLayeredPool* pool,
 151     int max_sockets,
 152     int max_sockets_per_group,
 153     base::TimeDelta unused_idle_socket_timeout,
 154     base::TimeDelta used_idle_socket_timeout,
 155     ConnectJobFactory* connect_job_factory)
 156     : idle_socket_count_(0),
 157       connecting_socket_count_(0),
 158       handed_out_socket_count_(0),
 159       max_sockets_(max_sockets),
 160       max_sockets_per_group_(max_sockets_per_group),
 161       use_cleanup_timer_(g_cleanup_timer_enabled),
 162       unused_idle_socket_timeout_(unused_idle_socket_timeout),
 163       used_idle_socket_timeout_(used_idle_socket_timeout),
 164       connect_job_factory_(connect_job_factory),
 165       connect_backup_jobs_enabled_(false),
 166       pool_generation_number_(0),
 167       pool_(pool),
 168       weak_factory_(this) {
 169   DCHECK_LE(0, max_sockets_per_group);
 170   DCHECK_LE(max_sockets_per_group, max_sockets);
 171
 172   NetworkChangeNotifier::AddIPAddressObserver(this);
 173 }
 174
 175 ClientSocketPoolBaseHelper::~ClientSocketPoolBaseHelper() {
 176   // Clean up any idle sockets and pending connect jobs.  Assert that we have no
 177   // remaining active sockets or pending requests.  They should have all been
 178   // cleaned up prior to |this| being destroyed.
 179   FlushWithError(ERR_ABORTED);
 180   DCHECK(group_map_.empty());
 181   DCHECK(pending_callback_map_.empty());
 182   DCHECK_EQ(0, connecting_socket_count_);
 183   CHECK(higher_pools_.empty());
 184
 185   NetworkChangeNotifier::RemoveIPAddressObserver(this);
 186
 187   // Remove from lower layer pools.
 188   for (std::set<LowerLayeredPool*>::iterator it = lower_pools_.begin();
 189        it != lower_pools_.end();
 190        ++it) {
 191     (*it)->RemoveHigherLayeredPool(pool_);
 192   }
 193 }
 194
 195 ClientSocketPoolBaseHelper::CallbackResultPair::CallbackResultPair()
 196     : result(OK) {
 197 }
 198
 199 ClientSocketPoolBaseHelper::CallbackResultPair::CallbackResultPair(
 200     const CompletionCallback& callback_in, int result_in)
 201     : callback(callback_in),
 202       result(result_in) {
 203 }
 204
 205 ClientSocketPoolBaseHelper::CallbackResultPair::~CallbackResultPair() {}
 206
 207 bool ClientSocketPoolBaseHelper::IsStalled() const {
 208   // If a lower layer pool is stalled, consider |this| stalled as well.
 209   for (std::set<LowerLayeredPool*>::const_iterator it = lower_pools_.begin();
 210        it != lower_pools_.end();
 211        ++it) {
 212     if ((*it)->IsStalled())
 213       return true;
 214   }
 215
 216   // If fewer than |max_sockets_| are in use, then clearly |this| is not
 217   // stalled.
 218   if ((handed_out_socket_count_ + connecting_socket_count_) < max_sockets_)
 219     return false;
 220   // So in order to be stalled, |this| must be using at least |max_sockets_| AND
 221   // |this| must have a request that is actually stalled on the global socket
 222   // limit.  To find such a request, look for a group that has more requests
 223   // than jobs AND where the number of sockets is less than
 224   // |max_sockets_per_group_|.  (If the number of sockets is equal to
 225   // |max_sockets_per_group_|, then the request is stalled on the group limit,
 226   // which does not count.)
 227   for (GroupMap::const_iterator it = group_map_.begin();
 228        it != group_map_.end(); ++it) {
 229     if (it->second->CanUseAdditionalSocketSlot(max_sockets_per_group_))
 230       return true;
 231   }
 232   return false;
 233 }
 234
 235 void ClientSocketPoolBaseHelper::AddLowerLayeredPool(
 236     LowerLayeredPool* lower_pool) {
 237   DCHECK(pool_);
 238   CHECK(!ContainsKey(lower_pools_, lower_pool));
 239   lower_pools_.insert(lower_pool);
 240   lower_pool->AddHigherLayeredPool(pool_);
 241 }
 242
 243 void ClientSocketPoolBaseHelper::AddHigherLayeredPool(
 244     HigherLayeredPool* higher_pool) {
 245   CHECK(higher_pool);
 246   CHECK(!ContainsKey(higher_pools_, higher_pool));
 247   higher_pools_.insert(higher_pool);
 248 }
 249
 250 void ClientSocketPoolBaseHelper::RemoveHigherLayeredPool(
 251     HigherLayeredPool* higher_pool) {
 252   CHECK(higher_pool);
 253   CHECK(ContainsKey(higher_pools_, higher_pool));
 254   higher_pools_.erase(higher_pool);
 255 }
 256
 257 int ClientSocketPoolBaseHelper::RequestSocket(
 258     const std::string& group_name,
 259     scoped_ptr<const Request> request) {
 260   CHECK(!request->callback().is_null());
 261   CHECK(request->handle());
 262
 263   // Cleanup any timed-out idle sockets if no timer is used.
 264   if (!use_cleanup_timer_)
 265     CleanupIdleSockets(false);
 266
 267   request->net_log().BeginEvent(NetLog::TYPE_SOCKET_POOL);
 268   Group* group = GetOrCreateGroup(group_name);
 269
 270   int rv = RequestSocketInternal(group_name, *request);
 271   if (rv != ERR_IO_PENDING) {
 272     request->net_log().EndEventWithNetErrorCode(NetLog::TYPE_SOCKET_POOL, rv);
 273     CHECK(!request->handle()->is_initialized());
 274     request.reset();
 275   } else {
 276     group->InsertPendingRequest(request.Pass());
 277     // Have to do this asynchronously, as closing sockets in higher level pools
 278     // call back in to |this|, which will cause all sorts of fun and exciting
 279     // re-entrancy issues if the socket pool is doing something else at the
 280     // time.
 281     if (group->CanUseAdditionalSocketSlot(max_sockets_per_group_)) {
 282       base::MessageLoop::current()->PostTask(
 283           FROM_HERE,
 284           base::Bind(
 285               &ClientSocketPoolBaseHelper::TryToCloseSocketsInLayeredPools,
 286               weak_factory_.GetWeakPtr()));
 287     }
 288   }
 289   return rv;
 290 }
 291
 292 void ClientSocketPoolBaseHelper::RequestSockets(
 293     const std::string& group_name,
 294     const Request& request,
 295     int num_sockets) {
 296   DCHECK(request.callback().is_null());
 297   DCHECK(!request.handle());
 298
 299   // Cleanup any timed out idle sockets if no timer is used.
 300   if (!use_cleanup_timer_)
 301     CleanupIdleSockets(false);
 302
 303   if (num_sockets > max_sockets_per_group_) {
 304     num_sockets = max_sockets_per_group_;
 305   }
 306
 307   request.net_log().BeginEvent(
 308       NetLog::TYPE_SOCKET_POOL_CONNECTING_N_SOCKETS,
 309       NetLog::IntegerCallback("num_sockets", num_sockets));
 310
 311   Group* group = GetOrCreateGroup(group_name);
 312
 313   // RequestSocketsInternal() may delete the group.
 314   bool deleted_group = false;
 315
 316   int rv = OK;
 317   for (int num_iterations_left = num_sockets;
 318        group->NumActiveSocketSlots() < num_sockets &&
 319        num_iterations_left > 0 ; num_iterations_left--) {
 320     rv = RequestSocketInternal(group_name, request);
 321     if (rv < 0 && rv != ERR_IO_PENDING) {
 322       // We're encountering a synchronous error.  Give up.
 323       if (!ContainsKey(group_map_, group_name))
 324         deleted_group = true;
 325       break;
 326     }
 327     if (!ContainsKey(group_map_, group_name)) {
 328       // Unexpected.  The group should only be getting deleted on synchronous
 329       // error.
 330       NOTREACHED();
 331       deleted_group = true;
 332       break;
 333     }
 334   }
 335
 336   if (!deleted_group && group->IsEmpty())
 337     RemoveGroup(group_name);
 338
 339   if (rv == ERR_IO_PENDING)
 340     rv = OK;
 341   request.net_log().EndEventWithNetErrorCode(
 342       NetLog::TYPE_SOCKET_POOL_CONNECTING_N_SOCKETS, rv);
 343 }
 344
 345 int ClientSocketPoolBaseHelper::RequestSocketInternal(
 346     const std::string& group_name,
 347     const Request& request) {
 348   ClientSocketHandle* const handle = request.handle();
 349   const bool preconnecting = !handle;
 350   Group* group = GetOrCreateGroup(group_name);
 351
 352   if (!(request.flags() & NO_IDLE_SOCKETS)) {
 353     // Try to reuse a socket.
 354     if (AssignIdleSocketToRequest(request, group))
 355       return OK;
 356   }
 357
 358   // If there are more ConnectJobs than pending requests, don't need to do
 359   // anything.  Can just wait for the extra job to connect, and then assign it
 360   // to the request.
 361   if (!preconnecting && group->TryToUseUnassignedConnectJob())
 362     return ERR_IO_PENDING;
 363
 364   // Can we make another active socket now?
 365   if (!group->HasAvailableSocketSlot(max_sockets_per_group_) &&
 366       !request.ignore_limits()) {
 367     // TODO(willchan): Consider whether or not we need to close a socket in a
 368     // higher layered group. I don't think this makes sense since we would just
 369     // reuse that socket then if we needed one and wouldn't make it down to this
 370     // layer.
 371     request.net_log().AddEvent(
 372         NetLog::TYPE_SOCKET_POOL_STALLED_MAX_SOCKETS_PER_GROUP);
 373     return ERR_IO_PENDING;
 374   }
 375
 376   if (ReachedMaxSocketsLimit() && !request.ignore_limits()) {
 377     // NOTE(mmenke):  Wonder if we really need different code for each case
 378     // here.  Only reason for them now seems to be preconnects.
 379     if (idle_socket_count() > 0) {
 380       // There's an idle socket in this pool. Either that's because there's
 381       // still one in this group, but we got here due to preconnecting bypassing
 382       // idle sockets, or because there's an idle socket in another group.
 383       bool closed = CloseOneIdleSocketExceptInGroup(group);
 384       if (preconnecting && !closed)
 385         return ERR_PRECONNECT_MAX_SOCKET_LIMIT;
 386     } else {
 387       // We could check if we really have a stalled group here, but it requires
 388       // a scan of all groups, so just flip a flag here, and do the check later.
 389       request.net_log().AddEvent(NetLog::TYPE_SOCKET_POOL_STALLED_MAX_SOCKETS);
 390       return ERR_IO_PENDING;
 391     }
 392   }
 393
 394   // We couldn't find a socket to reuse, and there's space to allocate one,
 395   // so allocate and connect a new one.
 396   scoped_ptr<ConnectJob> connect_job(
 397       connect_job_factory_->NewConnectJob(group_name, request, this));
 398
 399   int rv = connect_job->Connect();
 400   if (rv == OK) {
 401     LogBoundConnectJobToRequest(connect_job->net_log().source(), request);
 402     if (!preconnecting) {
 403       HandOutSocket(connect_job->PassSocket(), ClientSocketHandle::UNUSED,
 404                     connect_job->connect_timing(), handle, base::TimeDelta(),
 405                     group, request.net_log());
 406     } else {
 407       AddIdleSocket(connect_job->PassSocket(), group);
 408     }
 409   } else if (rv == ERR_IO_PENDING) {
 410     // If we don't have any sockets in this group, set a timer for potentially
 411     // creating a new one.  If the SYN is lost, this backup socket may complete
 412     // before the slow socket, improving end user latency.
 413     if (connect_backup_jobs_enabled_ && group->IsEmpty()) {
 414       group->StartBackupJobTimer(group_name, this);
 415     }
 416
 417     connecting_socket_count_++;
 418
 419     group->AddJob(connect_job.Pass(), preconnecting);
 420   } else {
 421     LogBoundConnectJobToRequest(connect_job->net_log().source(), request);
 422     scoped_ptr<StreamSocket> error_socket;
 423     if (!preconnecting) {
 424       DCHECK(handle);
 425       connect_job->GetAdditionalErrorState(handle);
 426       error_socket = connect_job->PassSocket();
 427     }
 428     if (error_socket) {
 429       HandOutSocket(error_socket.Pass(), ClientSocketHandle::UNUSED,
 430                     connect_job->connect_timing(), handle, base::TimeDelta(),
 431                     group, request.net_log());
 432     } else if (group->IsEmpty()) {
 433       RemoveGroup(group_name);
 434     }
 435   }
 436
 437   return rv;
 438 }
 439
 440 bool ClientSocketPoolBaseHelper::AssignIdleSocketToRequest(
 441     const Request& request, Group* group) {
 442   std::list<IdleSocket>* idle_sockets = group->mutable_idle_sockets();
 443   std::list<IdleSocket>::iterator idle_socket_it = idle_sockets->end();
 444
 445   // Iterate through the idle sockets forwards (oldest to newest)
 446   //   * Delete any disconnected ones.
 447   //   * If we find a used idle socket, assign to |idle_socket|.  At the end,
 448   //   the |idle_socket_it| will be set to the newest used idle socket.
 449   for (std::list<IdleSocket>::iterator it = idle_sockets->begin();
 450        it != idle_sockets->end();) {
 451     if (!it->IsUsable()) {
 452       DecrementIdleCount();
 453       delete it->socket;
 454       it = idle_sockets->erase(it);
 455       continue;
 456     }
 457
 458     if (it->socket->WasEverUsed()) {
 459       // We found one we can reuse!
 460       idle_socket_it = it;
 461     }
 462
 463     ++it;
 464   }
 465
 466   // If we haven't found an idle socket, that means there are no used idle
 467   // sockets.  Pick the oldest (first) idle socket (FIFO).
 468
 469   if (idle_socket_it == idle_sockets->end() && !idle_sockets->empty())
 470     idle_socket_it = idle_sockets->begin();
 471
 472   if (idle_socket_it != idle_sockets->end()) {
 473     DecrementIdleCount();
 474     base::TimeDelta idle_time =
 475         base::TimeTicks::Now() - idle_socket_it->start_time;
 476     IdleSocket idle_socket = *idle_socket_it;
 477     idle_sockets->erase(idle_socket_it);
 478     // TODO(davidben): If |idle_time| is under some low watermark, consider
 479     // treating as UNUSED rather than UNUSED_IDLE. This will avoid
 480     // HttpNetworkTransaction retrying on some errors.
 481     ClientSocketHandle::SocketReuseType reuse_type =
 482         idle_socket.socket->WasEverUsed() ?
 483             ClientSocketHandle::REUSED_IDLE :
 484             ClientSocketHandle::UNUSED_IDLE;
 485     HandOutSocket(
 486         scoped_ptr<StreamSocket>(idle_socket.socket),
 487         reuse_type,
 488         LoadTimingInfo::ConnectTiming(),
 489         request.handle(),
 490         idle_time,
 491         group,
 492         request.net_log());
 493     return true;
 494   }
 495
 496   return false;
 497 }
 498
 499 // static
 500 void ClientSocketPoolBaseHelper::LogBoundConnectJobToRequest(
 501     const NetLog::Source& connect_job_source, const Request& request) {
 502   request.net_log().AddEvent(NetLog::TYPE_SOCKET_POOL_BOUND_TO_CONNECT_JOB,
 503                              connect_job_source.ToEventParametersCallback());
 504 }
 505
 506 void ClientSocketPoolBaseHelper::CancelRequest(
 507     const std::string& group_name, ClientSocketHandle* handle) {
 508   PendingCallbackMap::iterator callback_it = pending_callback_map_.find(handle);
 509   if (callback_it != pending_callback_map_.end()) {
 510     int result = callback_it->second.result;
 511     pending_callback_map_.erase(callback_it);
 512     scoped_ptr<StreamSocket> socket = handle->PassSocket();
 513     if (socket) {
 514       if (result != OK)
 515         socket->Disconnect();
 516       ReleaseSocket(handle->group_name(), socket.Pass(), handle->id());
 517     }
 518     return;
 519   }
 520
 521   CHECK(ContainsKey(group_map_, group_name));
 522
 523   Group* group = GetOrCreateGroup(group_name);
 524
 525   // Search pending_requests for matching handle.
 526   scoped_ptr<const Request> request =
 527       group->FindAndRemovePendingRequest(handle);
 528   if (request) {
 529     request->net_log().AddEvent(NetLog::TYPE_CANCELLED);
 530     request->net_log().EndEvent(NetLog::TYPE_SOCKET_POOL);
 531
 532     // We let the job run, unless we're at the socket limit and there is
 533     // not another request waiting on the job.
 534     if (group->jobs().size() > group->pending_request_count() &&
 535         ReachedMaxSocketsLimit()) {
 536       RemoveConnectJob(*group->jobs().begin(), group);
 537       CheckForStalledSocketGroups();
 538     }
 539   }
 540 }
 541
 542 bool ClientSocketPoolBaseHelper::HasGroup(const std::string& group_name) const {
 543   return ContainsKey(group_map_, group_name);
 544 }
 545
 546 void ClientSocketPoolBaseHelper::CloseIdleSockets() {
 547   CleanupIdleSockets(true);
 548   DCHECK_EQ(0, idle_socket_count_);
 549 }
 550
 551 int ClientSocketPoolBaseHelper::IdleSocketCountInGroup(
 552     const std::string& group_name) const {
 553   GroupMap::const_iterator i = group_map_.find(group_name);
 554   CHECK(i != group_map_.end());
 555
 556   return i->second->idle_sockets().size();
 557 }
 558
 559 LoadState ClientSocketPoolBaseHelper::GetLoadState(
 560     const std::string& group_name,
 561     const ClientSocketHandle* handle) const {
 562   if (ContainsKey(pending_callback_map_, handle))
 563     return LOAD_STATE_CONNECTING;
 564
 565   GroupMap::const_iterator group_it = group_map_.find(group_name);
 566   // TODO(mmenke):  Switch to DCHECK once sure this doesn't break anything.
 567   //     Added in M43.
 568   CHECK(group_it != group_map_.end());
 569   const Group& group = *group_it->second;
 570
 571   if (group.HasConnectJobForHandle(handle)) {
 572     // Just return the state of the farthest along ConnectJob for the first
 573     // group.jobs().size() pending requests.
 574     LoadState max_state = LOAD_STATE_IDLE;
 575     for (const auto& job : group.jobs()) {
 576       max_state = std::max(max_state, job->GetLoadState());
 577     }
 578     return max_state;
 579   }
 580
 581   if (group.CanUseAdditionalSocketSlot(max_sockets_per_group_))
 582     return LOAD_STATE_WAITING_FOR_STALLED_SOCKET_POOL;
 583   return LOAD_STATE_WAITING_FOR_AVAILABLE_SOCKET;
 584 }
 585
 586 base::DictionaryValue* ClientSocketPoolBaseHelper::GetInfoAsValue(
 587     const std::string& name, const std::string& type) const {
 588   base::DictionaryValue* dict = new base::DictionaryValue();
 589   dict->SetString("name", name);
 590   dict->SetString("type", type);
 591   dict->SetInteger("handed_out_socket_count", handed_out_socket_count_);
 592   dict->SetInteger("connecting_socket_count", connecting_socket_count_);
 593   dict->SetInteger("idle_socket_count", idle_socket_count_);
 594   dict->SetInteger("max_socket_count", max_sockets_);
 595   dict->SetInteger("max_sockets_per_group", max_sockets_per_group_);
 596   dict->SetInteger("pool_generation_number", pool_generation_number_);
 597
 598   if (group_map_.empty())
 599     return dict;
 600
 601   base::DictionaryValue* all_groups_dict = new base::DictionaryValue();
 602   for (GroupMap::const_iterator it = group_map_.begin();
 603        it != group_map_.end(); it++) {
 604     const Group* group = it->second;
 605     base::DictionaryValue* group_dict = new base::DictionaryValue();
 606
 607     group_dict->SetInteger("pending_request_count",
 608                            group->pending_request_count());
 609     if (group->has_pending_requests()) {
 610       group_dict->SetString(
 611           "top_pending_priority",
 612           RequestPriorityToString(group->TopPendingPriority()));
 613     }
 614
 615     group_dict->SetInteger("active_socket_count", group->active_socket_count());
 616
 617     base::ListValue* idle_socket_list = new base::ListValue();
 618     std::list<IdleSocket>::const_iterator idle_socket;
 619     for (idle_socket = group->idle_sockets().begin();
 620          idle_socket != group->idle_sockets().end();
 621          idle_socket++) {
 622       int source_id = idle_socket->socket->NetLog().source().id;
 623       idle_socket_list->Append(new base::FundamentalValue(source_id));
 624     }
 625     group_dict->Set("idle_sockets", idle_socket_list);
 626
 627     base::ListValue* connect_jobs_list = new base::ListValue();
 628     std::set<ConnectJob*>::const_iterator job = group->jobs().begin();
 629     for (job = group->jobs().begin(); job != group->jobs().end(); job++) {
 630       int source_id = (*job)->net_log().source().id;
 631       connect_jobs_list->Append(new base::FundamentalValue(source_id));
 632     }
 633     group_dict->Set("connect_jobs", connect_jobs_list);
 634
 635     group_dict->SetBoolean("is_stalled", group->CanUseAdditionalSocketSlot(
 636                                              max_sockets_per_group_));
 637     group_dict->SetBoolean("backup_job_timer_is_running",
 638                            group->BackupJobTimerIsRunning());
 639
 640     all_groups_dict->SetWithoutPathExpansion(it->first, group_dict);
 641   }
 642   dict->Set("groups", all_groups_dict);
 643   return dict;
 644 }
 645
 646 bool ClientSocketPoolBaseHelper::IdleSocket::IsUsable() const {
 647   if (socket->WasEverUsed())
 648     return socket->IsConnectedAndIdle();
 649   return socket->IsConnected();
 650 }
 651
 652 bool ClientSocketPoolBaseHelper::IdleSocket::ShouldCleanup(
 653     base::TimeTicks now,
 654     base::TimeDelta timeout) const {
 655   bool timed_out = (now - start_time) >= timeout;
 656   if (timed_out)
 657     return true;
 658   return !IsUsable();
 659 }
 660
 661 void ClientSocketPoolBaseHelper::CleanupIdleSockets(bool force) {
 662   if (idle_socket_count_ == 0)
 663     return;
 664
 665   // Current time value. Retrieving it once at the function start rather than
 666   // inside the inner loop, since it shouldn't change by any meaningful amount.
 667   base::TimeTicks now = base::TimeTicks::Now();
 668
 669   GroupMap::iterator i = group_map_.begin();
 670   while (i != group_map_.end()) {
 671     Group* group = i->second;
 672
 673     std::list<IdleSocket>::iterator j = group->mutable_idle_sockets()->begin();
 674     while (j != group->idle_sockets().end()) {
 675       base::TimeDelta timeout =
 676           j->socket->WasEverUsed() ?
 677           used_idle_socket_timeout_ : unused_idle_socket_timeout_;
 678       if (force || j->ShouldCleanup(now, timeout)) {
 679         delete j->socket;
 680         j = group->mutable_idle_sockets()->erase(j);
 681         DecrementIdleCount();
 682       } else {
 683         ++j;
 684       }
 685     }
 686
 687     // Delete group if no longer needed.
 688     if (group->IsEmpty()) {
 689       RemoveGroup(i++);
 690     } else {
 691       ++i;
 692     }
 693   }
 694 }
 695
 696 ClientSocketPoolBaseHelper::Group* ClientSocketPoolBaseHelper::GetOrCreateGroup(
 697     const std::string& group_name) {
 698   GroupMap::iterator it = group_map_.find(group_name);
 699   if (it != group_map_.end())
 700     return it->second;
 701   Group* group = new Group;
 702   group_map_[group_name] = group;
 703   return group;
 704 }
 705
 706 void ClientSocketPoolBaseHelper::RemoveGroup(const std::string& group_name) {
 707   GroupMap::iterator it = group_map_.find(group_name);
 708   CHECK(it != group_map_.end());
 709
 710   RemoveGroup(it);
 711 }
 712
 713 void ClientSocketPoolBaseHelper::RemoveGroup(GroupMap::iterator it) {
 714   delete it->second;
 715   group_map_.erase(it);
 716 }
 717
 718 // static
 719 bool ClientSocketPoolBaseHelper::connect_backup_jobs_enabled() {
 720   return g_connect_backup_jobs_enabled;
 721 }
 722
 723 // static
 724 bool ClientSocketPoolBaseHelper::set_connect_backup_jobs_enabled(bool enabled) {
 725   bool old_value = g_connect_backup_jobs_enabled;
 726   g_connect_backup_jobs_enabled = enabled;
 727   return old_value;
 728 }
 729
 730 void ClientSocketPoolBaseHelper::EnableConnectBackupJobs() {
 731   connect_backup_jobs_enabled_ = g_connect_backup_jobs_enabled;
 732 }
 733
 734 void ClientSocketPoolBaseHelper::IncrementIdleCount() {
 735   if (++idle_socket_count_ == 1 && use_cleanup_timer_)
 736     StartIdleSocketTimer();
 737 }
 738
 739 void ClientSocketPoolBaseHelper::DecrementIdleCount() {
 740   if (--idle_socket_count_ == 0)
 741     timer_.Stop();
 742 }
 743
 744 // static
 745 bool ClientSocketPoolBaseHelper::cleanup_timer_enabled() {
 746   return g_cleanup_timer_enabled;
 747 }
 748
 749 // static
 750 bool ClientSocketPoolBaseHelper::set_cleanup_timer_enabled(bool enabled) {
 751   bool old_value = g_cleanup_timer_enabled;
 752   g_cleanup_timer_enabled = enabled;
 753   return old_value;
 754 }
 755
 756 void ClientSocketPoolBaseHelper::StartIdleSocketTimer() {
 757   timer_.Start(FROM_HERE, TimeDelta::FromSeconds(kCleanupInterval), this,
 758                &ClientSocketPoolBaseHelper::OnCleanupTimerFired);
 759 }
 760
 761 void ClientSocketPoolBaseHelper::ReleaseSocket(const std::string& group_name,
 762                                                scoped_ptr<StreamSocket> socket,
 763                                                int id) {
 764   GroupMap::iterator i = group_map_.find(group_name);
 765   CHECK(i != group_map_.end());
 766
 767   Group* group = i->second;
 768
 769   CHECK_GT(handed_out_socket_count_, 0);
 770   handed_out_socket_count_--;
 771
 772   CHECK_GT(group->active_socket_count(), 0);
 773   group->DecrementActiveSocketCount();
 774
 775   const bool can_reuse = socket->IsConnectedAndIdle() &&
 776       id == pool_generation_number_;
 777   if (can_reuse) {
 778     // Add it to the idle list.
 779     AddIdleSocket(socket.Pass(), group);
 780     OnAvailableSocketSlot(group_name, group);
 781   } else {
 782     socket.reset();
 783   }
 784
 785   CheckForStalledSocketGroups();
 786 }
 787
 788 void ClientSocketPoolBaseHelper::CheckForStalledSocketGroups() {
 789   // If we have idle sockets, see if we can give one to the top-stalled group.
 790   std::string top_group_name;
 791   Group* top_group = NULL;
 792   if (!FindTopStalledGroup(&top_group, &top_group_name)) {
 793     // There may still be a stalled group in a lower level pool.
 794     for (std::set<LowerLayeredPool*>::iterator it = lower_pools_.begin();
 795          it != lower_pools_.end();
 796          ++it) {
 797        if ((*it)->IsStalled()) {
 798          CloseOneIdleSocket();
 799          break;
 800        }
 801     }
 802     return;
 803   }
 804
 805   if (ReachedMaxSocketsLimit()) {
 806     if (idle_socket_count() > 0) {
 807       CloseOneIdleSocket();
 808     } else {
 809       // We can't activate more sockets since we're already at our global
 810       // limit.
 811       return;
 812     }
 813   }
 814
 815   // Note:  we don't loop on waking stalled groups.  If the stalled group is at
 816   //        its limit, may be left with other stalled groups that could be
 817   //        woken.  This isn't optimal, but there is no starvation, so to avoid
 818   //        the looping we leave it at this.
 819   OnAvailableSocketSlot(top_group_name, top_group);
 820 }
 821
 822 // Search for the highest priority pending request, amongst the groups that
 823 // are not at the |max_sockets_per_group_| limit. Note: for requests with
 824 // the same priority, the winner is based on group hash ordering (and not
 825 // insertion order).
 826 bool ClientSocketPoolBaseHelper::FindTopStalledGroup(
 827     Group** group,
 828     std::string* group_name) const {
 829   CHECK((group && group_name) || (!group && !group_name));
 830   Group* top_group = NULL;
 831   const std::string* top_group_name = NULL;
 832   bool has_stalled_group = false;
 833   for (GroupMap::const_iterator i = group_map_.begin();
 834        i != group_map_.end(); ++i) {
 835     Group* curr_group = i->second;
 836     if (!curr_group->has_pending_requests())
 837       continue;
 838     if (curr_group->CanUseAdditionalSocketSlot(max_sockets_per_group_)) {
 839       if (!group)
 840         return true;
 841       has_stalled_group = true;
 842       bool has_higher_priority = !top_group ||
 843           curr_group->TopPendingPriority() > top_group->TopPendingPriority();
 844       if (has_higher_priority) {
 845         top_group = curr_group;
 846         top_group_name = &i->first;
 847       }
 848     }
 849   }
 850
 851   if (top_group) {
 852     CHECK(group);
 853     *group = top_group;
 854     *group_name = *top_group_name;
 855   } else {
 856     CHECK(!has_stalled_group);
 857   }
 858   return has_stalled_group;
 859 }
 860
 861 void ClientSocketPoolBaseHelper::OnConnectJobComplete(
 862     int result, ConnectJob* job) {
 863   // TODO(vadimt): Remove ScopedTracker below once crbug.com/436634 is fixed.
 864   tracked_objects::ScopedTracker tracking_profile(
 865       FROM_HERE_WITH_EXPLICIT_FUNCTION(
 866           "436634 ClientSocketPoolBaseHelper::OnConnectJobComplete"));
 867
 868   DCHECK_NE(ERR_IO_PENDING, result);
 869   const std::string group_name = job->group_name();
 870   GroupMap::iterator group_it = group_map_.find(group_name);
 871   CHECK(group_it != group_map_.end());
 872   Group* group = group_it->second;
 873
 874   scoped_ptr<StreamSocket> socket = job->PassSocket();
 875
 876   // Copies of these are needed because |job| may be deleted before they are
 877   // accessed.
 878   BoundNetLog job_log = job->net_log();
 879   LoadTimingInfo::ConnectTiming connect_timing = job->connect_timing();
 880
 881   // RemoveConnectJob(job, _) must be called by all branches below;
 882   // otherwise, |job| will be leaked.
 883
 884   if (result == OK) {
 885     DCHECK(socket.get());
 886     RemoveConnectJob(job, group);
 887     scoped_ptr<const Request> request = group->PopNextPendingRequest();
 888     if (request) {
 889       LogBoundConnectJobToRequest(job_log.source(), *request);
 890       HandOutSocket(
 891           socket.Pass(), ClientSocketHandle::UNUSED, connect_timing,
 892           request->handle(), base::TimeDelta(), group, request->net_log());
 893       request->net_log().EndEvent(NetLog::TYPE_SOCKET_POOL);
 894       InvokeUserCallbackLater(request->handle(), request->callback(), result);
 895     } else {
 896       AddIdleSocket(socket.Pass(), group);
 897       OnAvailableSocketSlot(group_name, group);
 898       CheckForStalledSocketGroups();
 899     }
 900   } else {
 901     // If we got a socket, it must contain error information so pass that
 902     // up so that the caller can retrieve it.
 903     bool handed_out_socket = false;
 904     scoped_ptr<const Request> request = group->PopNextPendingRequest();
 905     if (request) {
 906       LogBoundConnectJobToRequest(job_log.source(), *request);
 907       job->GetAdditionalErrorState(request->handle());
 908       RemoveConnectJob(job, group);
 909       if (socket.get()) {
 910         handed_out_socket = true;
 911         HandOutSocket(socket.Pass(), ClientSocketHandle::UNUSED,
 912                       connect_timing, request->handle(), base::TimeDelta(),
 913                       group, request->net_log());
 914       }
 915       request->net_log().EndEventWithNetErrorCode(
 916           NetLog::TYPE_SOCKET_POOL, result);
 917       InvokeUserCallbackLater(request->handle(), request->callback(), result);
 918     } else {
 919       RemoveConnectJob(job, group);
 920     }
 921     if (!handed_out_socket) {
 922       OnAvailableSocketSlot(group_name, group);
 923       CheckForStalledSocketGroups();
 924     }
 925   }
 926 }
 927
 928 void ClientSocketPoolBaseHelper::OnIPAddressChanged() {
 929   FlushWithError(ERR_NETWORK_CHANGED);
 930 }
 931
 932 void ClientSocketPoolBaseHelper::FlushWithError(int error) {
 933   pool_generation_number_++;
 934   CancelAllConnectJobs();
 935   CloseIdleSockets();
 936   CancelAllRequestsWithError(error);
 937 }
 938
 939 void ClientSocketPoolBaseHelper::RemoveConnectJob(ConnectJob* job,
 940                                                   Group* group) {
 941   CHECK_GT(connecting_socket_count_, 0);
 942   connecting_socket_count_--;
 943
 944   DCHECK(group);
 945   group->RemoveJob(job);
 946 }
 947
 948 void ClientSocketPoolBaseHelper::OnAvailableSocketSlot(
 949     const std::string& group_name, Group* group) {
 950   DCHECK(ContainsKey(group_map_, group_name));
 951   if (group->IsEmpty()) {
 952     RemoveGroup(group_name);
 953   } else if (group->has_pending_requests()) {
 954     ProcessPendingRequest(group_name, group);
 955   }
 956 }
 957
 958 void ClientSocketPoolBaseHelper::ProcessPendingRequest(
 959     const std::string& group_name, Group* group) {
 960   const Request* next_request = group->GetNextPendingRequest();
 961   DCHECK(next_request);
 962
 963   // If the group has no idle sockets, and can't make use of an additional slot,
 964   // either because it's at the limit or because it's at the socket per group
 965   // limit, then there's nothing to do.
 966   if (group->idle_sockets().empty() &&
 967       !group->CanUseAdditionalSocketSlot(max_sockets_per_group_)) {
 968     return;
 969   }
 970
 971   int rv = RequestSocketInternal(group_name, *next_request);
 972   if (rv != ERR_IO_PENDING) {
 973     scoped_ptr<const Request> request = group->PopNextPendingRequest();
 974     DCHECK(request);
 975     if (group->IsEmpty())
 976       RemoveGroup(group_name);
 977
 978     request->net_log().EndEventWithNetErrorCode(NetLog::TYPE_SOCKET_POOL, rv);
 979     InvokeUserCallbackLater(request->handle(), request->callback(), rv);
 980   }
 981 }
 982
 983 void ClientSocketPoolBaseHelper::HandOutSocket(
 984     scoped_ptr<StreamSocket> socket,
 985     ClientSocketHandle::SocketReuseType reuse_type,
 986     const LoadTimingInfo::ConnectTiming& connect_timing,
 987     ClientSocketHandle* handle,
 988     base::TimeDelta idle_time,
 989     Group* group,
 990     const BoundNetLog& net_log) {
 991   DCHECK(socket);
 992   handle->SetSocket(socket.Pass());
 993   handle->set_reuse_type(reuse_type);
 994   handle->set_idle_time(idle_time);
 995   handle->set_pool_id(pool_generation_number_);
 996   handle->set_connect_timing(connect_timing);
 997
 998   if (handle->is_reused()) {
 999     net_log.AddEvent(
1000         NetLog::TYPE_SOCKET_POOL_REUSED_AN_EXISTING_SOCKET,
1001         NetLog::IntegerCallback(
1002             "idle_ms", static_cast<int>(idle_time.InMilliseconds())));
1003   }
1004
1005   net_log.AddEvent(
1006       NetLog::TYPE_SOCKET_POOL_BOUND_TO_SOCKET,
1007       handle->socket()->NetLog().source().ToEventParametersCallback());
1008
1009   handed_out_socket_count_++;
1010   group->IncrementActiveSocketCount();
1011 }
1012
1013 void ClientSocketPoolBaseHelper::AddIdleSocket(
1014     scoped_ptr<StreamSocket> socket,
1015     Group* group) {
1016   DCHECK(socket);
1017   IdleSocket idle_socket;
1018   idle_socket.socket = socket.release();
1019   idle_socket.start_time = base::TimeTicks::Now();
1020
1021   group->mutable_idle_sockets()->push_back(idle_socket);
1022   IncrementIdleCount();
1023 }
1024
1025 void ClientSocketPoolBaseHelper::CancelAllConnectJobs() {
1026   for (GroupMap::iterator i = group_map_.begin(); i != group_map_.end();) {
1027     Group* group = i->second;
1028     connecting_socket_count_ -= group->jobs().size();
1029     group->RemoveAllJobs();
1030
1031     // Delete group if no longer needed.
1032     if (group->IsEmpty()) {
1033       // RemoveGroup() will call .erase() which will invalidate the iterator,
1034       // but i will already have been incremented to a valid iterator before
1035       // RemoveGroup() is called.
1036       RemoveGroup(i++);
1037     } else {
1038       ++i;
1039     }
1040   }
1041   DCHECK_EQ(0, connecting_socket_count_);
1042 }
1043
1044 void ClientSocketPoolBaseHelper::CancelAllRequestsWithError(int error) {
1045   for (GroupMap::iterator i = group_map_.begin(); i != group_map_.end();) {
1046     Group* group = i->second;
1047
1048     while (true) {
1049       scoped_ptr<const Request> request = group->PopNextPendingRequest();
1050       if (!request)
1051         break;
1052       InvokeUserCallbackLater(request->handle(), request->callback(), error);
1053     }
1054
1055     // Delete group if no longer needed.
1056     if (group->IsEmpty()) {
1057       // RemoveGroup() will call .erase() which will invalidate the iterator,
1058       // but i will already have been incremented to a valid iterator before
1059       // RemoveGroup() is called.
1060       RemoveGroup(i++);
1061     } else {
1062       ++i;
1063     }
1064   }
1065 }
1066
1067 bool ClientSocketPoolBaseHelper::ReachedMaxSocketsLimit() const {
1068   // Each connecting socket will eventually connect and be handed out.
1069   int total = handed_out_socket_count_ + connecting_socket_count_ +
1070       idle_socket_count();
1071   // There can be more sockets than the limit since some requests can ignore
1072   // the limit
1073   if (total < max_sockets_)
1074     return false;
1075   return true;
1076 }
1077
1078 bool ClientSocketPoolBaseHelper::CloseOneIdleSocket() {
1079   if (idle_socket_count() == 0)
1080     return false;
1081   return CloseOneIdleSocketExceptInGroup(NULL);
1082 }
1083
1084 bool ClientSocketPoolBaseHelper::CloseOneIdleSocketExceptInGroup(
1085     const Group* exception_group) {
1086   CHECK_GT(idle_socket_count(), 0);
1087
1088   for (GroupMap::iterator i = group_map_.begin(); i != group_map_.end(); ++i) {
1089     Group* group = i->second;
1090     if (exception_group == group)
1091       continue;
1092     std::list<IdleSocket>* idle_sockets = group->mutable_idle_sockets();
1093
1094     if (!idle_sockets->empty()) {
1095       delete idle_sockets->front().socket;
1096       idle_sockets->pop_front();
1097       DecrementIdleCount();
1098       if (group->IsEmpty())
1099         RemoveGroup(i);
1100
1101       return true;
1102     }
1103   }
1104
1105   return false;
1106 }
1107
1108 bool ClientSocketPoolBaseHelper::CloseOneIdleConnectionInHigherLayeredPool() {
1109   // This pool doesn't have any idle sockets. It's possible that a pool at a
1110   // higher layer is holding one of this sockets active, but it's actually idle.
1111   // Query the higher layers.
1112   for (std::set<HigherLayeredPool*>::const_iterator it = higher_pools_.begin();
1113        it != higher_pools_.end(); ++it) {
1114     if ((*it)->CloseOneIdleConnection())
1115       return true;
1116   }
1117   return false;
1118 }
1119
1120 void ClientSocketPoolBaseHelper::InvokeUserCallbackLater(
1121     ClientSocketHandle* handle, const CompletionCallback& callback, int rv) {
1122   CHECK(!ContainsKey(pending_callback_map_, handle));
1123   pending_callback_map_[handle] = CallbackResultPair(callback, rv);
1124   base::MessageLoop::current()->PostTask(
1125       FROM_HERE,
1126       base::Bind(&ClientSocketPoolBaseHelper::InvokeUserCallback,
1127                  weak_factory_.GetWeakPtr(), handle));
1128 }
1129
1130 void ClientSocketPoolBaseHelper::InvokeUserCallback(
1131     ClientSocketHandle* handle) {
1132   PendingCallbackMap::iterator it = pending_callback_map_.find(handle);
1133
1134   // Exit if the request has already been cancelled.
1135   if (it == pending_callback_map_.end())
1136     return;
1137
1138   CHECK(!handle->is_initialized());
1139   CompletionCallback callback = it->second.callback;
1140   int result = it->second.result;
1141   pending_callback_map_.erase(it);
1142   callback.Run(result);
1143 }
1144
1145 void ClientSocketPoolBaseHelper::TryToCloseSocketsInLayeredPools() {
1146   while (IsStalled()) {
1147     // Closing a socket will result in calling back into |this| to use the freed
1148     // socket slot, so nothing else is needed.
1149     if (!CloseOneIdleConnectionInHigherLayeredPool())
1150       return;
1151   }
1152 }
1153
1154 ClientSocketPoolBaseHelper::Group::Group()
1155     : unassigned_job_count_(0),
1156       pending_requests_(NUM_PRIORITIES),
1157       active_socket_count_(0) {}
1158
1159 ClientSocketPoolBaseHelper::Group::~Group() {
1160   DCHECK_EQ(0u, unassigned_job_count_);
1161 }
1162
1163 void ClientSocketPoolBaseHelper::Group::StartBackupJobTimer(
1164     const std::string& group_name,
1165     ClientSocketPoolBaseHelper* pool) {
1166   // Only allow one timer to run at a time.
1167   if (BackupJobTimerIsRunning())
1168     return;
1169
1170   // Unretained here is okay because |backup_job_timer_| is
1171   // automatically cancelled when it's destroyed.
1172   backup_job_timer_.Start(
1173       FROM_HERE, pool->ConnectRetryInterval(),
1174       base::Bind(&Group::OnBackupJobTimerFired, base::Unretained(this),
1175                  group_name, pool));
1176 }
1177
1178 bool ClientSocketPoolBaseHelper::Group::BackupJobTimerIsRunning() const {
1179   return backup_job_timer_.IsRunning();
1180 }
1181
1182 bool ClientSocketPoolBaseHelper::Group::TryToUseUnassignedConnectJob() {
1183   SanityCheck();
1184
1185   if (unassigned_job_count_ == 0)
1186     return false;
1187   --unassigned_job_count_;
1188   return true;
1189 }
1190
1191 void ClientSocketPoolBaseHelper::Group::AddJob(scoped_ptr<ConnectJob> job,
1192                                                bool is_preconnect) {
1193   SanityCheck();
1194
1195   if (is_preconnect)
1196     ++unassigned_job_count_;
1197   jobs_.insert(job.release());
1198 }
1199
1200 void ClientSocketPoolBaseHelper::Group::RemoveJob(ConnectJob* job) {
1201   scoped_ptr<ConnectJob> owned_job(job);
1202   SanityCheck();
1203
1204   std::set<ConnectJob*>::iterator it = jobs_.find(job);
1205   if (it != jobs_.end()) {
1206     jobs_.erase(it);
1207   } else {
1208     NOTREACHED();
1209   }
1210   size_t job_count = jobs_.size();
1211   if (job_count < unassigned_job_count_)
1212     unassigned_job_count_ = job_count;
1213
1214   // If we've got no more jobs for this group, then we no longer need a
1215   // backup job either.
1216   if (jobs_.empty())
1217     backup_job_timer_.Stop();
1218 }
1219
1220 void ClientSocketPoolBaseHelper::Group::OnBackupJobTimerFired(
1221     std::string group_name,
1222     ClientSocketPoolBaseHelper* pool) {
1223   // If there are no more jobs pending, there is no work to do.
1224   // If we've done our cleanups correctly, this should not happen.
1225   if (jobs_.empty()) {
1226     NOTREACHED();
1227     return;
1228   }
1229
1230   // If our old job is waiting on DNS, or if we can't create any sockets
1231   // right now due to limits, just reset the timer.
1232   if (pool->ReachedMaxSocketsLimit() ||
1233       !HasAvailableSocketSlot(pool->max_sockets_per_group_) ||
1234       (*jobs_.begin())->GetLoadState() == LOAD_STATE_RESOLVING_HOST) {
1235     StartBackupJobTimer(group_name, pool);
1236     return;
1237   }
1238
1239   if (pending_requests_.empty())
1240     return;
1241
1242   scoped_ptr<ConnectJob> backup_job =
1243       pool->connect_job_factory_->NewConnectJob(
1244           group_name, *pending_requests_.FirstMax().value(), pool);
1245   backup_job->net_log().AddEvent(NetLog::TYPE_BACKUP_CONNECT_JOB_CREATED);
1246   int rv = backup_job->Connect();
1247   pool->connecting_socket_count_++;
1248   ConnectJob* raw_backup_job = backup_job.get();
1249   AddJob(backup_job.Pass(), false);
1250   if (rv != ERR_IO_PENDING)
1251     pool->OnConnectJobComplete(rv, raw_backup_job);
1252 }
1253
1254 void ClientSocketPoolBaseHelper::Group::SanityCheck() {
1255   DCHECK_LE(unassigned_job_count_, jobs_.size());
1256 }
1257
1258 void ClientSocketPoolBaseHelper::Group::RemoveAllJobs() {
1259   SanityCheck();
1260
1261   // Delete active jobs.
1262   STLDeleteElements(&jobs_);
1263   unassigned_job_count_ = 0;
1264
1265   // Stop backup job timer.
1266   backup_job_timer_.Stop();
1267 }
1268
1269 const ClientSocketPoolBaseHelper::Request*
1270 ClientSocketPoolBaseHelper::Group::GetNextPendingRequest() const {
1271   return
1272       pending_requests_.empty() ? NULL : pending_requests_.FirstMax().value();
1273 }
1274
1275 bool ClientSocketPoolBaseHelper::Group::HasConnectJobForHandle(
1276     const ClientSocketHandle* handle) const {
1277   // Search the first |jobs_.size()| pending requests for |handle|.
1278   // If it's farther back in the deque than that, it doesn't have a
1279   // corresponding ConnectJob.
1280   size_t i = 0;
1281   for (RequestQueue::Pointer pointer = pending_requests_.FirstMax();
1282        !pointer.is_null() && i < jobs_.size();
1283        pointer = pending_requests_.GetNextTowardsLastMin(pointer), ++i) {
1284     if (pointer.value()->handle() == handle)
1285       return true;
1286   }
1287   return false;
1288 }
1289
1290 void ClientSocketPoolBaseHelper::Group::InsertPendingRequest(
1291     scoped_ptr<const Request> request) {
1292   // This value must be cached before we release |request|.
1293   RequestPriority priority = request->priority();
1294   if (request->ignore_limits()) {
1295     // Put requests with ignore_limits == true (which should have
1296     // priority == MAXIMUM_PRIORITY) ahead of other requests with
1297     // MAXIMUM_PRIORITY.
1298     DCHECK_EQ(priority, MAXIMUM_PRIORITY);
1299     pending_requests_.InsertAtFront(request.release(), priority);
1300   } else {
1301     pending_requests_.Insert(request.release(), priority);
1302   }
1303 }
1304
1305 scoped_ptr<const ClientSocketPoolBaseHelper::Request>
1306 ClientSocketPoolBaseHelper::Group::PopNextPendingRequest() {
1307   if (pending_requests_.empty())
1308     return scoped_ptr<const ClientSocketPoolBaseHelper::Request>();
1309   return RemovePendingRequest(pending_requests_.FirstMax());
1310 }
1311
1312 scoped_ptr<const ClientSocketPoolBaseHelper::Request>
1313 ClientSocketPoolBaseHelper::Group::FindAndRemovePendingRequest(
1314     ClientSocketHandle* handle) {
1315   for (RequestQueue::Pointer pointer = pending_requests_.FirstMax();
1316        !pointer.is_null();
1317        pointer = pending_requests_.GetNextTowardsLastMin(pointer)) {
1318     if (pointer.value()->handle() == handle) {
1319       scoped_ptr<const Request> request = RemovePendingRequest(pointer);
1320       return request.Pass();
1321     }
1322   }
1323   return scoped_ptr<const ClientSocketPoolBaseHelper::Request>();
1324 }
1325
1326 scoped_ptr<const ClientSocketPoolBaseHelper::Request>
1327 ClientSocketPoolBaseHelper::Group::RemovePendingRequest(
1328     const RequestQueue::Pointer& pointer) {
1329   scoped_ptr<const Request> request(pointer.value());
1330   pending_requests_.Erase(pointer);
1331   // If there are no more requests, kill the backup timer.
1332   if (pending_requests_.empty())
1333     backup_job_timer_.Stop();
1334   return request.Pass();
1335 }
1336
1337 }  // namespace internal
1338
1339 }  // namespace net