src/chrome/browser/prerender/prerender_link_manager.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 "chrome/browser/prerender/prerender_link_manager.h"
   6
   7 #include <functional>
   8 #include <limits>
   9 #include <set>
  10 #include <string>
  11 #include <utility>
  12
  13 #include "base/memory/scoped_ptr.h"
  14 #include "base/metrics/field_trial.h"
  15 #include "base/metrics/histogram.h"
  16 #include "chrome/browser/prerender/prerender_contents.h"
  17 #include "chrome/browser/prerender/prerender_handle.h"
  18 #include "chrome/browser/prerender/prerender_manager.h"
  19 #include "chrome/browser/prerender/prerender_manager_factory.h"
  20 #include "chrome/browser/profiles/profile.h"
  21 #include "chrome/common/prerender_messages.h"
  22 #include "chrome/common/prerender_types.h"
  23 #include "content/public/browser/render_process_host.h"
  24 #include "content/public/browser/render_view_host.h"
  25 #include "content/public/browser/session_storage_namespace.h"
  26 #include "content/public/common/referrer.h"
  27 #include "ui/gfx/size.h"
  28 #include "url/gurl.h"
  29
  30 #if defined(ENABLE_EXTENSIONS)
  31 #include "extensions/browser/guest_view/guest_view_base.h"
  32 #endif
  33
  34 using base::TimeDelta;
  35 using base::TimeTicks;
  36 using content::RenderViewHost;
  37 using content::SessionStorageNamespace;
  38
  39 namespace prerender {
  40
  41 namespace {
  42
  43 bool ShouldStartRelNextPrerenders() {
  44   const std::string experiment_name =
  45       base::FieldTrialList::FindFullName("PrerenderRelNextTrial");
  46
  47   return experiment_name.find("Yes") != std::string::npos;
  48 }
  49
  50 bool ShouldStartPrerender(const uint32 rel_types) {
  51   const bool should_start_rel_next_prerenders =
  52       ShouldStartRelNextPrerenders();
  53
  54   if (rel_types & PrerenderRelTypePrerender) {
  55     return true;
  56   } else if (should_start_rel_next_prerenders &&
  57              (rel_types & PrerenderRelTypeNext) == PrerenderRelTypeNext) {
  58     return true;
  59   }
  60   return false;
  61 }
  62
  63 COMPILE_ASSERT(PrerenderRelTypePrerender == 0x1,
  64                RelTypeHistogramEnum_must_match_PrerenderRelType);
  65 COMPILE_ASSERT(PrerenderRelTypeNext == 0x2,
  66                RelTypeHistogramEnum_must_match_PrerenderRelType);
  67 enum RelTypeHistogramEnum {
  68   RelTypeHistogramEnumNone = 0,
  69   RelTypeHistogramEnumPrerender = PrerenderRelTypePrerender,
  70   RelTypeHistogramEnumNext = PrerenderRelTypeNext,
  71   RelTypeHistogramEnumPrerenderAndNext =
  72       PrerenderRelTypePrerender | PrerenderRelTypeNext,
  73   RelTypeHistogramEnumMax,
  74 };
  75
  76 void RecordLinkManagerAdded(const uint32 rel_types) {
  77   const uint32 enum_value = rel_types & (RelTypeHistogramEnumMax - 1);
  78   UMA_HISTOGRAM_ENUMERATION("Prerender.RelTypesLinkAdded", enum_value,
  79                             RelTypeHistogramEnumMax);
  80 }
  81
  82 void RecordLinkManagerStarting(const uint32 rel_types) {
  83   const uint32 enum_value = rel_types & (RelTypeHistogramEnumMax - 1);
  84   UMA_HISTOGRAM_ENUMERATION("Prerender.RelTypesLinkStarted", enum_value,
  85                             RelTypeHistogramEnumMax);
  86 }
  87
  88 void Send(int child_id, IPC::Message* raw_message) {
  89   using content::RenderProcessHost;
  90   scoped_ptr<IPC::Message> own_message(raw_message);
  91
  92   RenderProcessHost* render_process_host = RenderProcessHost::FromID(child_id);
  93   if (!render_process_host)
  94     return;
  95   render_process_host->Send(own_message.release());
  96 }
  97
  98 }  // namespace
  99
 100 // Helper class to implement PrerenderContents::Observer and watch prerenders
 101 // which launch other prerenders.
 102 class PrerenderLinkManager::PendingPrerenderManager
 103     : public PrerenderContents::Observer {
 104  public:
 105   explicit PendingPrerenderManager(PrerenderLinkManager* link_manager)
 106       : link_manager_(link_manager) {}
 107
 108   ~PendingPrerenderManager() override {
 109     DCHECK(observed_launchers_.empty());
 110     for (std::set<PrerenderContents*>::iterator i = observed_launchers_.begin();
 111          i != observed_launchers_.end(); ++i) {
 112       (*i)->RemoveObserver(this);
 113     }
 114   }
 115
 116   void ObserveLauncher(PrerenderContents* launcher) {
 117     DCHECK_EQ(FINAL_STATUS_MAX, launcher->final_status());
 118     if (observed_launchers_.find(launcher) != observed_launchers_.end())
 119       return;
 120     observed_launchers_.insert(launcher);
 121     launcher->AddObserver(this);
 122   }
 123
 124   void OnPrerenderStart(PrerenderContents* launcher) override {}
 125
 126   void OnPrerenderStop(PrerenderContents* launcher) override {
 127     observed_launchers_.erase(launcher);
 128     if (launcher->final_status() == FINAL_STATUS_USED) {
 129       link_manager_->StartPendingPrerendersForLauncher(launcher);
 130     } else {
 131       link_manager_->CancelPendingPrerendersForLauncher(launcher);
 132     }
 133   }
 134
 135  private:
 136   // A pointer to the parent PrerenderLinkManager.
 137   PrerenderLinkManager* link_manager_;
 138
 139   // The set of PrerenderContentses being observed. Lifetimes are managed by
 140   // OnPrerenderStop.
 141   std::set<PrerenderContents*> observed_launchers_;
 142 };
 143
 144 PrerenderLinkManager::PrerenderLinkManager(PrerenderManager* manager)
 145     : has_shutdown_(false),
 146       manager_(manager),
 147       pending_prerender_manager_(new PendingPrerenderManager(this)) {}
 148
 149 PrerenderLinkManager::~PrerenderLinkManager() {
 150   for (std::list<LinkPrerender>::iterator i = prerenders_.begin();
 151        i != prerenders_.end(); ++i) {
 152     if (i->handle) {
 153       DCHECK(!i->handle->IsPrerendering())
 154           << "All running prerenders should stop at the same time as the "
 155           << "PrerenderManager.";
 156       delete i->handle;
 157       i->handle = 0;
 158     }
 159   }
 160 }
 161
 162 void PrerenderLinkManager::OnAddPrerender(int launcher_child_id,
 163                                           int prerender_id,
 164                                           const GURL& url,
 165                                           uint32 rel_types,
 166                                           const content::Referrer& referrer,
 167                                           const gfx::Size& size,
 168                                           int render_view_route_id) {
 169   DCHECK_EQ(static_cast<LinkPrerender*>(NULL),
 170             FindByLauncherChildIdAndPrerenderId(launcher_child_id,
 171                                                 prerender_id));
 172
 173 #if defined(ENABLE_EXTENSIONS)
 174   content::RenderViewHost* rvh =
 175       content::RenderViewHost::FromID(launcher_child_id, render_view_route_id);
 176   content::WebContents* web_contents =
 177       rvh ? content::WebContents::FromRenderViewHost(rvh) : NULL;
 178   // Guests inside <webview> do not support cross-process navigation and so we
 179   // do not allow guests to prerender content.
 180   if (extensions::GuestViewBase::IsGuest(web_contents))
 181     return;
 182 #endif
 183
 184   // Check if the launcher is itself an unswapped prerender.
 185   PrerenderContents* prerender_contents =
 186       manager_->GetPrerenderContentsForRoute(launcher_child_id,
 187                                              render_view_route_id);
 188   if (prerender_contents &&
 189       prerender_contents->final_status() != FINAL_STATUS_MAX) {
 190     // The launcher is a prerender about to be destroyed asynchronously, but
 191     // its AddLinkRelPrerender message raced with shutdown. Ignore it.
 192     DCHECK_NE(FINAL_STATUS_USED, prerender_contents->final_status());
 193     return;
 194   }
 195
 196   LinkPrerender
 197       prerender(launcher_child_id, prerender_id, url, rel_types, referrer, size,
 198                 render_view_route_id, manager_->GetCurrentTimeTicks(),
 199                 prerender_contents);
 200   prerenders_.push_back(prerender);
 201   RecordLinkManagerAdded(rel_types);
 202   if (prerender_contents)
 203     pending_prerender_manager_->ObserveLauncher(prerender_contents);
 204   else
 205     StartPrerenders();
 206 }
 207
 208 void PrerenderLinkManager::OnCancelPrerender(int child_id, int prerender_id) {
 209   LinkPrerender* prerender = FindByLauncherChildIdAndPrerenderId(child_id,
 210                                                                  prerender_id);
 211   if (!prerender)
 212     return;
 213
 214   CancelPrerender(prerender);
 215   StartPrerenders();
 216 }
 217
 218 void PrerenderLinkManager::OnAbandonPrerender(int child_id, int prerender_id) {
 219   LinkPrerender* prerender = FindByLauncherChildIdAndPrerenderId(child_id,
 220                                                                  prerender_id);
 221   if (!prerender)
 222     return;
 223
 224   if (!prerender->handle) {
 225     RemovePrerender(prerender);
 226     return;
 227   }
 228
 229   prerender->has_been_abandoned = true;
 230   prerender->handle->OnNavigateAway();
 231   DCHECK(prerender->handle);
 232
 233   // If the prerender is not running, remove it from the list so it does not
 234   // leak. If it is running, it will send a cancel event when it stops which
 235   // will remove it.
 236   if (!prerender->handle->IsPrerendering())
 237     RemovePrerender(prerender);
 238 }
 239
 240 void PrerenderLinkManager::OnChannelClosing(int child_id) {
 241   std::list<LinkPrerender>::iterator next = prerenders_.begin();
 242   while (next != prerenders_.end()) {
 243     std::list<LinkPrerender>::iterator it = next;
 244     ++next;
 245
 246     if (child_id != it->launcher_child_id)
 247       continue;
 248
 249     const size_t running_prerender_count = CountRunningPrerenders();
 250     OnAbandonPrerender(child_id, it->prerender_id);
 251     DCHECK_EQ(running_prerender_count, CountRunningPrerenders());
 252   }
 253 }
 254
 255 PrerenderLinkManager::LinkPrerender::LinkPrerender(
 256     int launcher_child_id,
 257     int prerender_id,
 258     const GURL& url,
 259     uint32 rel_types,
 260     const content::Referrer& referrer,
 261     const gfx::Size& size,
 262     int render_view_route_id,
 263     TimeTicks creation_time,
 264     PrerenderContents* deferred_launcher)
 265     : launcher_child_id(launcher_child_id),
 266       prerender_id(prerender_id),
 267       url(url),
 268       rel_types(rel_types),
 269       referrer(referrer),
 270       size(size),
 271       render_view_route_id(render_view_route_id),
 272       creation_time(creation_time),
 273       deferred_launcher(deferred_launcher),
 274       handle(NULL),
 275       is_match_complete_replacement(false),
 276       has_been_abandoned(false) {
 277 }
 278
 279 PrerenderLinkManager::LinkPrerender::~LinkPrerender() {
 280   DCHECK_EQ(static_cast<PrerenderHandle*>(NULL), handle)
 281       << "The PrerenderHandle should be destroyed before its Prerender.";
 282 }
 283
 284 bool PrerenderLinkManager::IsEmpty() const {
 285   return prerenders_.empty();
 286 }
 287
 288 size_t PrerenderLinkManager::CountRunningPrerenders() const {
 289   size_t retval = 0;
 290   for (std::list<LinkPrerender>::const_iterator i = prerenders_.begin();
 291        i != prerenders_.end(); ++i) {
 292     if (i->handle && i->handle->IsPrerendering())
 293       ++retval;
 294   }
 295   return retval;
 296 }
 297
 298 void PrerenderLinkManager::StartPrerenders() {
 299   if (has_shutdown_)
 300     return;
 301
 302   size_t total_started_prerender_count = 0;
 303   std::list<LinkPrerender*> abandoned_prerenders;
 304   std::list<std::list<LinkPrerender>::iterator> pending_prerenders;
 305   std::multiset<std::pair<int, int> >
 306       running_launcher_and_render_view_routes;
 307
 308   // Scan the list, counting how many prerenders have handles (and so were added
 309   // to the PrerenderManager). The count is done for the system as a whole, and
 310   // also per launcher.
 311   for (std::list<LinkPrerender>::iterator i = prerenders_.begin();
 312        i != prerenders_.end(); ++i) {
 313     // Skip prerenders launched by a prerender.
 314     if (i->deferred_launcher)
 315       continue;
 316     if (!i->handle) {
 317       pending_prerenders.push_back(i);
 318     } else {
 319       ++total_started_prerender_count;
 320       if (i->has_been_abandoned) {
 321         abandoned_prerenders.push_back(&(*i));
 322       } else {
 323         // We do not count abandoned prerenders towards their launcher, since it
 324         // has already navigated on to another page.
 325         std::pair<int, int> launcher_and_render_view_route(
 326             i->launcher_child_id, i->render_view_route_id);
 327         running_launcher_and_render_view_routes.insert(
 328             launcher_and_render_view_route);
 329         DCHECK_GE(manager_->config().max_link_concurrency_per_launcher,
 330                   running_launcher_and_render_view_routes.count(
 331                       launcher_and_render_view_route));
 332       }
 333     }
 334
 335     DCHECK_EQ(&(*i), FindByLauncherChildIdAndPrerenderId(i->launcher_child_id,
 336                                                          i->prerender_id));
 337   }
 338   DCHECK_LE(abandoned_prerenders.size(), total_started_prerender_count);
 339   DCHECK_GE(manager_->config().max_link_concurrency,
 340             total_started_prerender_count);
 341   DCHECK_LE(CountRunningPrerenders(), total_started_prerender_count);
 342
 343   TimeTicks now = manager_->GetCurrentTimeTicks();
 344
 345   // Scan the pending prerenders, starting prerenders as we can.
 346   for (std::list<std::list<LinkPrerender>::iterator>::const_iterator
 347            i = pending_prerenders.begin(), end = pending_prerenders.end();
 348        i != end; ++i) {
 349     TimeDelta prerender_age = now - (*i)->creation_time;
 350     if (prerender_age >= manager_->config().max_wait_to_launch) {
 351       // This prerender waited too long in the queue before launching.
 352       prerenders_.erase(*i);
 353       continue;
 354     }
 355
 356     std::pair<int, int> launcher_and_render_view_route(
 357         (*i)->launcher_child_id, (*i)->render_view_route_id);
 358     if (manager_->config().max_link_concurrency_per_launcher <=
 359         running_launcher_and_render_view_routes.count(
 360             launcher_and_render_view_route)) {
 361       // This prerender's launcher is already at its limit.
 362       continue;
 363     }
 364
 365     if (total_started_prerender_count >=
 366             manager_->config().max_link_concurrency ||
 367         total_started_prerender_count >= prerenders_.size()) {
 368       // The system is already at its prerender concurrency limit. Can we kill
 369       // an abandoned prerender to make room?
 370       if (!abandoned_prerenders.empty()) {
 371         CancelPrerender(abandoned_prerenders.front());
 372         --total_started_prerender_count;
 373         abandoned_prerenders.pop_front();
 374       } else {
 375         return;
 376       }
 377     }
 378
 379     if (!ShouldStartPrerender((*i)->rel_types)) {
 380       prerenders_.erase(*i);
 381       continue;
 382     }
 383
 384     PrerenderHandle* handle = manager_->AddPrerenderFromLinkRelPrerender(
 385         (*i)->launcher_child_id, (*i)->render_view_route_id,
 386         (*i)->url, (*i)->rel_types, (*i)->referrer, (*i)->size);
 387     if (!handle) {
 388       // This prerender couldn't be launched, it's gone.
 389       prerenders_.erase(*i);
 390       continue;
 391     }
 392
 393     // We have successfully started a new prerender.
 394     (*i)->handle = handle;
 395     ++total_started_prerender_count;
 396     handle->SetObserver(this);
 397     if (handle->IsPrerendering())
 398       OnPrerenderStart(handle);
 399     RecordLinkManagerStarting((*i)->rel_types);
 400
 401     running_launcher_and_render_view_routes.insert(
 402         launcher_and_render_view_route);
 403   }
 404 }
 405
 406 PrerenderLinkManager::LinkPrerender*
 407 PrerenderLinkManager::FindByLauncherChildIdAndPrerenderId(int launcher_child_id,
 408                                                           int prerender_id) {
 409   for (std::list<LinkPrerender>::iterator i = prerenders_.begin();
 410        i != prerenders_.end(); ++i) {
 411     if (launcher_child_id == i->launcher_child_id &&
 412         prerender_id == i->prerender_id) {
 413       return &(*i);
 414     }
 415   }
 416   return NULL;
 417 }
 418
 419 PrerenderLinkManager::LinkPrerender*
 420 PrerenderLinkManager::FindByPrerenderHandle(PrerenderHandle* prerender_handle) {
 421   DCHECK(prerender_handle);
 422   for (std::list<LinkPrerender>::iterator i = prerenders_.begin();
 423        i != prerenders_.end(); ++i) {
 424     if (prerender_handle == i->handle)
 425       return &(*i);
 426   }
 427   return NULL;
 428 }
 429
 430 void PrerenderLinkManager::RemovePrerender(LinkPrerender* prerender) {
 431   for (std::list<LinkPrerender>::iterator i = prerenders_.begin();
 432        i != prerenders_.end(); ++i) {
 433     if (&(*i) == prerender) {
 434       scoped_ptr<PrerenderHandle> own_handle(i->handle);
 435       i->handle = NULL;
 436       prerenders_.erase(i);
 437       return;
 438     }
 439   }
 440   NOTREACHED();
 441 }
 442
 443 void PrerenderLinkManager::CancelPrerender(LinkPrerender* prerender) {
 444   for (std::list<LinkPrerender>::iterator i = prerenders_.begin();
 445        i != prerenders_.end(); ++i) {
 446     if (&(*i) == prerender) {
 447       scoped_ptr<PrerenderHandle> own_handle(i->handle);
 448       i->handle = NULL;
 449       prerenders_.erase(i);
 450       if (own_handle)
 451         own_handle->OnCancel();
 452       return;
 453     }
 454   }
 455   NOTREACHED();
 456 }
 457
 458 void PrerenderLinkManager::StartPendingPrerendersForLauncher(
 459     PrerenderContents* launcher) {
 460   for (std::list<LinkPrerender>::iterator i = prerenders_.begin();
 461        i != prerenders_.end(); ++i) {
 462     if (i->deferred_launcher == launcher)
 463       i->deferred_launcher = NULL;
 464   }
 465   StartPrerenders();
 466 }
 467
 468 void PrerenderLinkManager::CancelPendingPrerendersForLauncher(
 469     PrerenderContents* launcher) {
 470   // Remove all pending prerenders for this launcher.
 471   std::vector<std::list<LinkPrerender>::iterator> to_erase;
 472   for (std::list<LinkPrerender>::iterator i = prerenders_.begin();
 473        i != prerenders_.end(); ++i) {
 474     if (i->deferred_launcher == launcher) {
 475       DCHECK(!i->handle);
 476       to_erase.push_back(i);
 477     }
 478   }
 479   std::for_each(to_erase.begin(), to_erase.end(),
 480                 std::bind1st(std::mem_fun(&std::list<LinkPrerender>::erase),
 481                              &prerenders_));
 482 }
 483
 484 void PrerenderLinkManager::Shutdown() {
 485   has_shutdown_ = true;
 486 }
 487
 488 // In practice, this is always called from PrerenderLinkManager::OnAddPrerender.
 489 void PrerenderLinkManager::OnPrerenderStart(
 490     PrerenderHandle* prerender_handle) {
 491   LinkPrerender* prerender = FindByPrerenderHandle(prerender_handle);
 492   if (!prerender)
 493     return;
 494   Send(prerender->launcher_child_id,
 495        new PrerenderMsg_OnPrerenderStart(prerender->prerender_id));
 496 }
 497
 498 void PrerenderLinkManager::OnPrerenderStopLoading(
 499     PrerenderHandle* prerender_handle) {
 500   LinkPrerender* prerender = FindByPrerenderHandle(prerender_handle);
 501   if (!prerender)
 502     return;
 503
 504   Send(prerender->launcher_child_id,
 505        new PrerenderMsg_OnPrerenderStopLoading(prerender->prerender_id));
 506 }
 507
 508 void PrerenderLinkManager::OnPrerenderDomContentLoaded(
 509     PrerenderHandle* prerender_handle) {
 510   LinkPrerender* prerender = FindByPrerenderHandle(prerender_handle);
 511   if (!prerender)
 512     return;
 513
 514   Send(prerender->launcher_child_id,
 515        new PrerenderMsg_OnPrerenderDomContentLoaded(prerender->prerender_id));
 516 }
 517
 518 void PrerenderLinkManager::OnPrerenderStop(
 519     PrerenderHandle* prerender_handle) {
 520   LinkPrerender* prerender = FindByPrerenderHandle(prerender_handle);
 521   if (!prerender)
 522     return;
 523
 524   // If the prerender became a match complete replacement, the stop
 525   // message has already been sent.
 526   if (!prerender->is_match_complete_replacement) {
 527     Send(prerender->launcher_child_id,
 528          new PrerenderMsg_OnPrerenderStop(prerender->prerender_id));
 529   }
 530   RemovePrerender(prerender);
 531   StartPrerenders();
 532 }
 533
 534 void PrerenderLinkManager::OnPrerenderCreatedMatchCompleteReplacement(
 535     PrerenderHandle* prerender_handle) {
 536   LinkPrerender* prerender = FindByPrerenderHandle(prerender_handle);
 537   if (!prerender)
 538     return;
 539
 540   DCHECK(!prerender->is_match_complete_replacement);
 541   prerender->is_match_complete_replacement = true;
 542   Send(prerender->launcher_child_id,
 543        new PrerenderMsg_OnPrerenderStop(prerender->prerender_id));
 544   // Do not call RemovePrerender here. The replacement needs to stay connected
 545   // to the HTMLLinkElement in the renderer so it notices renderer-triggered
 546   // cancelations.
 547 }
 548
 549 }  // namespace prerender