history_backend.cc revision f8ee788a64d60abd8f2d742a5fdedde054ecd910
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/history/history_backend.h"
6
7#include <algorithm>
8#include <functional>
9#include <list>
10#include <map>
11#include <set>
12#include <vector>
13
14#include "base/basictypes.h"
15#include "base/bind.h"
16#include "base/compiler_specific.h"
17#include "base/files/file_enumerator.h"
18#include "base/memory/scoped_ptr.h"
19#include "base/memory/scoped_vector.h"
20#include "base/message_loop/message_loop.h"
21#include "base/metrics/histogram.h"
22#include "base/rand_util.h"
23#include "base/strings/string_util.h"
24#include "base/strings/utf_string_conversions.h"
25#include "base/time/time.h"
26#include "chrome/browser/autocomplete/history_url_provider.h"
27#include "chrome/browser/chrome_notification_types.h"
28#include "chrome/browser/favicon/favicon_changed_details.h"
29#include "chrome/browser/history/download_row.h"
30#include "chrome/browser/history/history_db_task.h"
31#include "chrome/browser/history/history_notifications.h"
32#include "chrome/browser/history/in_memory_history_backend.h"
33#include "chrome/browser/history/page_usage_data.h"
34#include "chrome/browser/history/top_sites.h"
35#include "chrome/browser/history/typed_url_syncable_service.h"
36#include "chrome/browser/history/visit_filter.h"
37#include "chrome/common/chrome_constants.h"
38#include "chrome/common/importer/imported_favicon_usage.h"
39#include "chrome/common/url_constants.h"
40#include "components/favicon_base/select_favicon_frames.h"
41#include "components/history/core/browser/history_client.h"
42#include "grit/chromium_strings.h"
43#include "grit/generated_resources.h"
44#include "net/base/registry_controlled_domains/registry_controlled_domain.h"
45#include "sql/error_delegate_util.h"
46#include "url/gurl.h"
47
48#if defined(OS_ANDROID)
49#include "chrome/browser/history/android/android_provider_backend.h"
50#endif
51
52using base::Time;
53using base::TimeDelta;
54using base::TimeTicks;
55
56/* The HistoryBackend consists of two components:
57
58    HistoryDatabase (stores past 3 months of history)
59      URLDatabase (stores a list of URLs)
60      DownloadDatabase (stores a list of downloads)
61      VisitDatabase (stores a list of visits for the URLs)
62      VisitSegmentDatabase (stores groups of URLs for the most visited view).
63
64    ExpireHistoryBackend (manages deleting things older than 3 months)
65*/
66
67namespace history {
68
69// How long we keep segment data for in days. Currently 3 months.
70// This value needs to be greater or equal to
71// MostVisitedModel::kMostVisitedScope but we don't want to introduce a direct
72// dependency between MostVisitedModel and the history backend.
73const int kSegmentDataRetention = 90;
74
75// How long we'll wait to do a commit, so that things are batched together.
76const int kCommitIntervalSeconds = 10;
77
78// The amount of time before we re-fetch the favicon.
79const int kFaviconRefetchDays = 7;
80
81// The maximum number of items we'll allow in the redirect list before
82// deleting some.
83const int kMaxRedirectCount = 32;
84
85// The number of days old a history entry can be before it is considered "old"
86// and is deleted.
87const int kExpireDaysThreshold = 90;
88
89#if defined(OS_ANDROID)
90// The maximum number of top sites to track when recording top page visit stats.
91const size_t kPageVisitStatsMaxTopSites = 50;
92#endif
93
94// Converts from PageUsageData to MostVisitedURL. |redirects| is a
95// list of redirects for this URL. Empty list means no redirects.
96MostVisitedURL MakeMostVisitedURL(const PageUsageData& page_data,
97                                  const RedirectList& redirects) {
98  MostVisitedURL mv;
99  mv.url = page_data.GetURL();
100  mv.title = page_data.GetTitle();
101  if (redirects.empty()) {
102    // Redirects must contain at least the target url.
103    mv.redirects.push_back(mv.url);
104  } else {
105    mv.redirects = redirects;
106    if (mv.redirects[mv.redirects.size() - 1] != mv.url) {
107      // The last url must be the target url.
108      mv.redirects.push_back(mv.url);
109    }
110  }
111  return mv;
112}
113
114// This task is run on a timer so that commits happen at regular intervals
115// so they are batched together. The important thing about this class is that
116// it supports canceling of the task so the reference to the backend will be
117// freed. The problem is that when history is shutting down, there is likely
118// to be one of these commits still pending and holding a reference.
119//
120// The backend can call Cancel to have this task release the reference. The
121// task will still run (if we ever get to processing the event before
122// shutdown), but it will not do anything.
123//
124// Note that this is a refcounted object and is not a task in itself. It should
125// be assigned to a RunnableMethod.
126//
127// TODO(brettw): bug 1165182: This should be replaced with a
128// base::WeakPtrFactory which will handle everything automatically (like we do
129// in ExpireHistoryBackend).
130class CommitLaterTask : public base::RefCounted<CommitLaterTask> {
131 public:
132  explicit CommitLaterTask(HistoryBackend* history_backend)
133      : history_backend_(history_backend) {
134  }
135
136  // The backend will call this function if it is being destroyed so that we
137  // release our reference.
138  void Cancel() {
139    history_backend_ = NULL;
140  }
141
142  void RunCommit() {
143    if (history_backend_.get())
144      history_backend_->Commit();
145  }
146
147 private:
148  friend class base::RefCounted<CommitLaterTask>;
149
150  ~CommitLaterTask() {}
151
152  scoped_refptr<HistoryBackend> history_backend_;
153};
154
155// HistoryBackend::QueryURLResult ----------------------------------------------
156
157HistoryBackend::QueryURLResult::QueryURLResult() : success(false) {
158}
159
160HistoryBackend::QueryURLResult::~QueryURLResult() {
161}
162
163// HistoryBackend --------------------------------------------------------------
164
165HistoryBackend::HistoryBackend(const base::FilePath& history_dir,
166                               Delegate* delegate,
167                               HistoryClient* history_client)
168    : delegate_(delegate),
169      history_dir_(history_dir),
170      scheduled_kill_db_(false),
171      expirer_(this, history_client),
172      recent_redirects_(kMaxRedirectCount),
173      backend_destroy_message_loop_(NULL),
174      segment_queried_(false),
175      history_client_(history_client) {
176}
177
178HistoryBackend::~HistoryBackend() {
179  DCHECK(!scheduled_commit_.get()) << "Deleting without cleanup";
180  ReleaseDBTasks();
181
182#if defined(OS_ANDROID)
183  // Release AndroidProviderBackend before other objects.
184  android_provider_backend_.reset();
185#endif
186
187  // First close the databases before optionally running the "destroy" task.
188  CloseAllDatabases();
189
190  if (!backend_destroy_task_.is_null()) {
191    // Notify an interested party (typically a unit test) that we're done.
192    DCHECK(backend_destroy_message_loop_);
193    backend_destroy_message_loop_->PostTask(FROM_HERE, backend_destroy_task_);
194  }
195
196#if defined(OS_ANDROID)
197  sql::Connection::Delete(GetAndroidCacheFileName());
198#endif
199}
200
201void HistoryBackend::Init(const std::string& languages, bool force_fail) {
202  if (!force_fail)
203    InitImpl(languages);
204  delegate_->DBLoaded();
205  typed_url_syncable_service_.reset(new TypedUrlSyncableService(this));
206  memory_pressure_listener_.reset(new base::MemoryPressureListener(
207      base::Bind(&HistoryBackend::OnMemoryPressure, base::Unretained(this))));
208#if defined(OS_ANDROID)
209  PopulateMostVisitedURLMap();
210#endif
211}
212
213void HistoryBackend::SetOnBackendDestroyTask(base::MessageLoop* message_loop,
214                                             const base::Closure& task) {
215  if (!backend_destroy_task_.is_null())
216    DLOG(WARNING) << "Setting more than one destroy task, overriding";
217  backend_destroy_message_loop_ = message_loop;
218  backend_destroy_task_ = task;
219}
220
221void HistoryBackend::Closing() {
222  // Any scheduled commit will have a reference to us, we must make it
223  // release that reference before we can be destroyed.
224  CancelScheduledCommit();
225
226  // Release our reference to the delegate, this reference will be keeping the
227  // history service alive.
228  delegate_.reset();
229}
230
231void HistoryBackend::ClearCachedDataForContextID(ContextID context_id) {
232  tracker_.ClearCachedDataForContextID(context_id);
233}
234
235base::FilePath HistoryBackend::GetThumbnailFileName() const {
236  return history_dir_.Append(chrome::kThumbnailsFilename);
237}
238
239base::FilePath HistoryBackend::GetFaviconsFileName() const {
240  return history_dir_.Append(chrome::kFaviconsFilename);
241}
242
243base::FilePath HistoryBackend::GetArchivedFileName() const {
244  return history_dir_.Append(chrome::kArchivedHistoryFilename);
245}
246
247#if defined(OS_ANDROID)
248base::FilePath HistoryBackend::GetAndroidCacheFileName() const {
249  return history_dir_.Append(chrome::kAndroidCacheFilename);
250}
251#endif
252
253SegmentID HistoryBackend::GetLastSegmentID(VisitID from_visit) {
254  // Set is used to detect referrer loops.  Should not happen, but can
255  // if the database is corrupt.
256  std::set<VisitID> visit_set;
257  VisitID visit_id = from_visit;
258  while (visit_id) {
259    VisitRow row;
260    if (!db_->GetRowForVisit(visit_id, &row))
261      return 0;
262    if (row.segment_id)
263      return row.segment_id;  // Found a visit in this change with a segment.
264
265    // Check the referrer of this visit, if any.
266    visit_id = row.referring_visit;
267
268    if (visit_set.find(visit_id) != visit_set.end()) {
269      NOTREACHED() << "Loop in referer chain, giving up";
270      break;
271    }
272    visit_set.insert(visit_id);
273  }
274  return 0;
275}
276
277SegmentID HistoryBackend::UpdateSegments(
278    const GURL& url,
279    VisitID from_visit,
280    VisitID visit_id,
281    content::PageTransition transition_type,
282    const Time ts) {
283  if (!db_)
284    return 0;
285
286  // We only consider main frames.
287  if (!content::PageTransitionIsMainFrame(transition_type))
288    return 0;
289
290  SegmentID segment_id = 0;
291  content::PageTransition t =
292      content::PageTransitionStripQualifier(transition_type);
293
294  // Are we at the beginning of a new segment?
295  // Note that navigating to an existing entry (with back/forward) reuses the
296  // same transition type.  We are not adding it as a new segment in that case
297  // because if this was the target of a redirect, we might end up with
298  // 2 entries for the same final URL. Ex: User types google.net, gets
299  // redirected to google.com. A segment is created for google.net. On
300  // google.com users navigates through a link, then press back. That last
301  // navigation is for the entry google.com transition typed. We end up adding
302  // a segment for that one as well. So we end up with google.net and google.com
303  // in the segment table, showing as 2 entries in the NTP.
304  // Note also that we should still be updating the visit count for that segment
305  // which we are not doing now. It should be addressed when
306  // http://crbug.com/96860 is fixed.
307  if ((t == content::PAGE_TRANSITION_TYPED ||
308       t == content::PAGE_TRANSITION_AUTO_BOOKMARK) &&
309      (transition_type & content::PAGE_TRANSITION_FORWARD_BACK) == 0) {
310    // If so, create or get the segment.
311    std::string segment_name = db_->ComputeSegmentName(url);
312    URLID url_id = db_->GetRowForURL(url, NULL);
313    if (!url_id)
314      return 0;
315
316    if (!(segment_id = db_->GetSegmentNamed(segment_name))) {
317      if (!(segment_id = db_->CreateSegment(url_id, segment_name))) {
318        NOTREACHED();
319        return 0;
320      }
321    } else {
322      // Note: if we update an existing segment, we update the url used to
323      // represent that segment in order to minimize stale most visited
324      // images.
325      db_->UpdateSegmentRepresentationURL(segment_id, url_id);
326    }
327  } else {
328    // Note: it is possible there is no segment ID set for this visit chain.
329    // This can happen if the initial navigation wasn't AUTO_BOOKMARK or
330    // TYPED. (For example GENERATED). In this case this visit doesn't count
331    // toward any segment.
332    if (!(segment_id = GetLastSegmentID(from_visit)))
333      return 0;
334  }
335
336  // Set the segment in the visit.
337  if (!db_->SetSegmentID(visit_id, segment_id)) {
338    NOTREACHED();
339    return 0;
340  }
341
342  // Finally, increase the counter for that segment / day.
343  if (!db_->IncreaseSegmentVisitCount(segment_id, ts, 1)) {
344    NOTREACHED();
345    return 0;
346  }
347  return segment_id;
348}
349
350void HistoryBackend::UpdateWithPageEndTime(ContextID context_id,
351                                           int32 page_id,
352                                           const GURL& url,
353                                           Time end_ts) {
354  // Will be filled with the URL ID and the visit ID of the last addition.
355  VisitID visit_id = tracker_.GetLastVisit(context_id, page_id, url);
356  UpdateVisitDuration(visit_id, end_ts);
357}
358
359void HistoryBackend::UpdateVisitDuration(VisitID visit_id, const Time end_ts) {
360  if (!db_)
361    return;
362
363  // Get the starting visit_time for visit_id.
364  VisitRow visit_row;
365  if (db_->GetRowForVisit(visit_id, &visit_row)) {
366    // We should never have a negative duration time even when time is skewed.
367    visit_row.visit_duration = end_ts > visit_row.visit_time ?
368        end_ts - visit_row.visit_time : TimeDelta::FromMicroseconds(0);
369    db_->UpdateVisitRow(visit_row);
370  }
371}
372
373void HistoryBackend::AddPage(const HistoryAddPageArgs& request) {
374  if (!db_)
375    return;
376
377  // Will be filled with the URL ID and the visit ID of the last addition.
378  std::pair<URLID, VisitID> last_ids(0, tracker_.GetLastVisit(
379      request.context_id, request.page_id, request.referrer));
380
381  VisitID from_visit_id = last_ids.second;
382
383  // If a redirect chain is given, we expect the last item in that chain to be
384  // the final URL.
385  DCHECK(request.redirects.empty() ||
386         request.redirects.back() == request.url);
387
388  // If the user is adding older history, we need to make sure our times
389  // are correct.
390  if (request.time < first_recorded_time_)
391    first_recorded_time_ = request.time;
392
393  content::PageTransition request_transition = request.transition;
394  content::PageTransition stripped_transition =
395    content::PageTransitionStripQualifier(request_transition);
396  bool is_keyword_generated =
397      (stripped_transition == content::PAGE_TRANSITION_KEYWORD_GENERATED);
398
399  // If the user is navigating to a not-previously-typed intranet hostname,
400  // change the transition to TYPED so that the omnibox will learn that this is
401  // a known host.
402  bool has_redirects = request.redirects.size() > 1;
403  if (content::PageTransitionIsMainFrame(request_transition) &&
404      (stripped_transition != content::PAGE_TRANSITION_TYPED) &&
405      !is_keyword_generated) {
406    const GURL& origin_url(has_redirects ?
407        request.redirects[0] : request.url);
408    if (origin_url.SchemeIs(url::kHttpScheme) ||
409        origin_url.SchemeIs(url::kHttpsScheme) ||
410        origin_url.SchemeIs(url::kFtpScheme)) {
411      std::string host(origin_url.host());
412      size_t registry_length =
413          net::registry_controlled_domains::GetRegistryLength(
414              host,
415              net::registry_controlled_domains::EXCLUDE_UNKNOWN_REGISTRIES,
416              net::registry_controlled_domains::EXCLUDE_PRIVATE_REGISTRIES);
417      if (registry_length == 0 && !db_->IsTypedHost(host)) {
418        stripped_transition = content::PAGE_TRANSITION_TYPED;
419        request_transition =
420            content::PageTransitionFromInt(
421                stripped_transition |
422                content::PageTransitionGetQualifier(request_transition));
423      }
424    }
425  }
426
427  if (!has_redirects) {
428    // The single entry is both a chain start and end.
429    content::PageTransition t = content::PageTransitionFromInt(
430        request_transition |
431        content::PAGE_TRANSITION_CHAIN_START |
432        content::PAGE_TRANSITION_CHAIN_END);
433
434    // No redirect case (one element means just the page itself).
435    last_ids = AddPageVisit(request.url, request.time,
436                            last_ids.second, t, request.visit_source);
437
438    // Update the segment for this visit. KEYWORD_GENERATED visits should not
439    // result in changing most visited, so we don't update segments (most
440    // visited db).
441    if (!is_keyword_generated) {
442      UpdateSegments(request.url, from_visit_id, last_ids.second, t,
443                     request.time);
444
445      // Update the referrer's duration.
446      UpdateVisitDuration(from_visit_id, request.time);
447    }
448  } else {
449    // Redirect case. Add the redirect chain.
450
451    content::PageTransition redirect_info =
452        content::PAGE_TRANSITION_CHAIN_START;
453
454    RedirectList redirects = request.redirects;
455    if (redirects[0].SchemeIs(url::kAboutScheme)) {
456      // When the redirect source + referrer is "about" we skip it. This
457      // happens when a page opens a new frame/window to about:blank and then
458      // script sets the URL to somewhere else (used to hide the referrer). It
459      // would be nice to keep all these redirects properly but we don't ever
460      // see the initial about:blank load, so we don't know where the
461      // subsequent client redirect came from.
462      //
463      // In this case, we just don't bother hooking up the source of the
464      // redirects, so we remove it.
465      redirects.erase(redirects.begin());
466    } else if (request_transition & content::PAGE_TRANSITION_CLIENT_REDIRECT) {
467      redirect_info = content::PAGE_TRANSITION_CLIENT_REDIRECT;
468      // The first entry in the redirect chain initiated a client redirect.
469      // We don't add this to the database since the referrer is already
470      // there, so we skip over it but change the transition type of the first
471      // transition to client redirect.
472      //
473      // The referrer is invalid when restoring a session that features an
474      // https tab that redirects to a different host or to http. In this
475      // case we don't need to reconnect the new redirect with the existing
476      // chain.
477      if (request.referrer.is_valid()) {
478        DCHECK(request.referrer == redirects[0]);
479        redirects.erase(redirects.begin());
480
481        // If the navigation entry for this visit has replaced that for the
482        // first visit, remove the CHAIN_END marker from the first visit. This
483        // can be called a lot, for example, the page cycler, and most of the
484        // time we won't have changed anything.
485        VisitRow visit_row;
486        if (request.did_replace_entry &&
487            db_->GetRowForVisit(last_ids.second, &visit_row) &&
488            visit_row.transition & content::PAGE_TRANSITION_CHAIN_END) {
489          visit_row.transition = content::PageTransitionFromInt(
490              visit_row.transition & ~content::PAGE_TRANSITION_CHAIN_END);
491          db_->UpdateVisitRow(visit_row);
492        }
493      }
494    }
495
496    for (size_t redirect_index = 0; redirect_index < redirects.size();
497         redirect_index++) {
498      content::PageTransition t =
499          content::PageTransitionFromInt(stripped_transition | redirect_info);
500
501      // If this is the last transition, add a CHAIN_END marker
502      if (redirect_index == (redirects.size() - 1)) {
503        t = content::PageTransitionFromInt(
504            t | content::PAGE_TRANSITION_CHAIN_END);
505      }
506
507      // Record all redirect visits with the same timestamp. We don't display
508      // them anyway, and if we ever decide to, we can reconstruct their order
509      // from the redirect chain.
510      last_ids = AddPageVisit(redirects[redirect_index],
511                              request.time, last_ids.second,
512                              t, request.visit_source);
513      if (t & content::PAGE_TRANSITION_CHAIN_START) {
514        // Update the segment for this visit.
515        UpdateSegments(redirects[redirect_index],
516                       from_visit_id, last_ids.second, t, request.time);
517
518        // Update the visit_details for this visit.
519        UpdateVisitDuration(from_visit_id, request.time);
520      }
521
522      // Subsequent transitions in the redirect list must all be server
523      // redirects.
524      redirect_info = content::PAGE_TRANSITION_SERVER_REDIRECT;
525    }
526
527    // Last, save this redirect chain for later so we can set titles & favicons
528    // on the redirected pages properly.
529    recent_redirects_.Put(request.url, redirects);
530  }
531
532  // TODO(brettw) bug 1140015: Add an "add page" notification so the history
533  // views can keep in sync.
534
535  // Add the last visit to the tracker so we can get outgoing transitions.
536  // TODO(evanm): Due to http://b/1194536 we lose the referrers of a subframe
537  // navigation anyway, so last_visit_id is always zero for them.  But adding
538  // them here confuses main frame history, so we skip them for now.
539  if (stripped_transition != content::PAGE_TRANSITION_AUTO_SUBFRAME &&
540      stripped_transition != content::PAGE_TRANSITION_MANUAL_SUBFRAME &&
541      !is_keyword_generated) {
542    tracker_.AddVisit(request.context_id, request.page_id, request.url,
543                      last_ids.second);
544  }
545
546  ScheduleCommit();
547}
548
549void HistoryBackend::InitImpl(const std::string& languages) {
550  DCHECK(!db_) << "Initializing HistoryBackend twice";
551  // In the rare case where the db fails to initialize a dialog may get shown
552  // the blocks the caller, yet allows other messages through. For this reason
553  // we only set db_ to the created database if creation is successful. That
554  // way other methods won't do anything as db_ is still NULL.
555
556  TimeTicks beginning_time = TimeTicks::Now();
557
558  // Compute the file names.
559  base::FilePath history_name = history_dir_.Append(chrome::kHistoryFilename);
560  base::FilePath thumbnail_name = GetFaviconsFileName();
561  base::FilePath archived_name = GetArchivedFileName();
562
563  // Delete the old index database files which are no longer used.
564  DeleteFTSIndexDatabases();
565
566  // History database.
567  db_.reset(new HistoryDatabase());
568
569  // Unretained to avoid a ref loop with db_.
570  db_->set_error_callback(
571      base::Bind(&HistoryBackend::DatabaseErrorCallback,
572                 base::Unretained(this)));
573
574  sql::InitStatus status = db_->Init(history_name);
575  switch (status) {
576    case sql::INIT_OK:
577      break;
578    case sql::INIT_FAILURE: {
579      // A NULL db_ will cause all calls on this object to notice this error
580      // and to not continue. If the error callback scheduled killing the
581      // database, the task it posted has not executed yet. Try killing the
582      // database now before we close it.
583      bool kill_db = scheduled_kill_db_;
584      if (kill_db)
585        KillHistoryDatabase();
586      UMA_HISTOGRAM_BOOLEAN("History.AttemptedToFixProfileError", kill_db);
587      delegate_->NotifyProfileError(status);
588      db_.reset();
589      return;
590    }
591    default:
592      NOTREACHED();
593  }
594
595  // Fill the in-memory database and send it back to the history service on the
596  // main thread.
597  {
598    scoped_ptr<InMemoryHistoryBackend> mem_backend(new InMemoryHistoryBackend);
599    if (mem_backend->Init(history_name, db_.get()))
600      delegate_->SetInMemoryBackend(mem_backend.Pass());
601  }
602  db_->BeginExclusiveMode();  // Must be after the mem backend read the data.
603
604  // Thumbnail database.
605  // TODO(shess): "thumbnail database" these days only stores
606  // favicons.  Thumbnails are stored in "top sites".  Consider
607  // renaming "thumbnail" references to "favicons" or something of the
608  // sort.
609  thumbnail_db_.reset(new ThumbnailDatabase());
610  if (thumbnail_db_->Init(thumbnail_name) != sql::INIT_OK) {
611    // Unlike the main database, we don't error out when the database is too
612    // new because this error is much less severe. Generally, this shouldn't
613    // happen since the thumbnail and main database versions should be in sync.
614    // We'll just continue without thumbnails & favicons in this case or any
615    // other error.
616    LOG(WARNING) << "Could not initialize the thumbnail database.";
617    thumbnail_db_.reset();
618  }
619
620  // Nuke any files corresponding to the legacy Archived History Database, which
621  // previously retained expired (> 3 months old) history entries, but, in the
622  // end, was not used for much, and consequently has been removed as of M37.
623  // TODO(engedy): Remove this code after the end of 2014.
624  sql::Connection::Delete(archived_name);
625
626  // Generate the history and thumbnail database metrics only after performing
627  // any migration work.
628  if (base::RandInt(1, 100) == 50) {
629    // Only do this computation sometimes since it can be expensive.
630    db_->ComputeDatabaseMetrics(history_name);
631    if (thumbnail_db_)
632      thumbnail_db_->ComputeDatabaseMetrics();
633  }
634
635  expirer_.SetDatabases(db_.get(), thumbnail_db_.get());
636
637  // Open the long-running transaction.
638  db_->BeginTransaction();
639  if (thumbnail_db_)
640    thumbnail_db_->BeginTransaction();
641
642  // Get the first item in our database.
643  db_->GetStartDate(&first_recorded_time_);
644
645  // Start expiring old stuff.
646  expirer_.StartExpiringOldStuff(TimeDelta::FromDays(kExpireDaysThreshold));
647
648#if defined(OS_ANDROID)
649  if (thumbnail_db_) {
650    android_provider_backend_.reset(
651        new AndroidProviderBackend(GetAndroidCacheFileName(),
652                                   db_.get(),
653                                   thumbnail_db_.get(),
654                                   history_client_,
655                                   delegate_.get()));
656  }
657#endif
658
659  HISTOGRAM_TIMES("History.InitTime",
660                  TimeTicks::Now() - beginning_time);
661}
662
663void HistoryBackend::OnMemoryPressure(
664    base::MemoryPressureListener::MemoryPressureLevel memory_pressure_level) {
665  bool trim_aggressively = memory_pressure_level ==
666      base::MemoryPressureListener::MEMORY_PRESSURE_CRITICAL;
667  if (db_)
668    db_->TrimMemory(trim_aggressively);
669  if (thumbnail_db_)
670    thumbnail_db_->TrimMemory(trim_aggressively);
671}
672
673void HistoryBackend::CloseAllDatabases() {
674  if (db_) {
675    // Commit the long-running transaction.
676    db_->CommitTransaction();
677    db_.reset();
678    // Forget the first recorded time since the database is closed.
679    first_recorded_time_ = base::Time();
680  }
681  if (thumbnail_db_) {
682    thumbnail_db_->CommitTransaction();
683    thumbnail_db_.reset();
684  }
685}
686
687std::pair<URLID, VisitID> HistoryBackend::AddPageVisit(
688    const GURL& url,
689    Time time,
690    VisitID referring_visit,
691    content::PageTransition transition,
692    VisitSource visit_source) {
693  // Top-level frame navigations are visible, everything else is hidden
694  bool new_hidden = !content::PageTransitionIsMainFrame(transition);
695
696  // NOTE: This code must stay in sync with
697  // ExpireHistoryBackend::ExpireURLsForVisits().
698  // TODO(pkasting): http://b/1148304 We shouldn't be marking so many URLs as
699  // typed, which would eliminate the need for this code.
700  int typed_increment = 0;
701  content::PageTransition transition_type =
702      content::PageTransitionStripQualifier(transition);
703  if ((transition_type == content::PAGE_TRANSITION_TYPED &&
704      !content::PageTransitionIsRedirect(transition)) ||
705      transition_type == content::PAGE_TRANSITION_KEYWORD_GENERATED)
706    typed_increment = 1;
707
708#if defined(OS_ANDROID)
709  // Only count the page visit if it came from user browsing and only count it
710  // once when cycling through a redirect chain.
711  if (visit_source == SOURCE_BROWSED &&
712      (transition & content::PAGE_TRANSITION_CHAIN_END) != 0) {
713    RecordTopPageVisitStats(url);
714  }
715#endif
716
717  // See if this URL is already in the DB.
718  URLRow url_info(url);
719  URLID url_id = db_->GetRowForURL(url, &url_info);
720  if (url_id) {
721    // Update of an existing row.
722    if (content::PageTransitionStripQualifier(transition) !=
723        content::PAGE_TRANSITION_RELOAD)
724      url_info.set_visit_count(url_info.visit_count() + 1);
725    if (typed_increment)
726      url_info.set_typed_count(url_info.typed_count() + typed_increment);
727    if (url_info.last_visit() < time)
728      url_info.set_last_visit(time);
729
730    // Only allow un-hiding of pages, never hiding.
731    if (!new_hidden)
732      url_info.set_hidden(false);
733
734    db_->UpdateURLRow(url_id, url_info);
735  } else {
736    // Addition of a new row.
737    url_info.set_visit_count(1);
738    url_info.set_typed_count(typed_increment);
739    url_info.set_last_visit(time);
740    url_info.set_hidden(new_hidden);
741
742    url_id = db_->AddURL(url_info);
743    if (!url_id) {
744      NOTREACHED() << "Adding URL failed.";
745      return std::make_pair(0, 0);
746    }
747    url_info.id_ = url_id;
748  }
749
750  // Add the visit with the time to the database.
751  VisitRow visit_info(url_id, time, referring_visit, transition, 0);
752  VisitID visit_id = db_->AddVisit(&visit_info, visit_source);
753  NotifyVisitObservers(visit_info);
754
755  if (visit_info.visit_time < first_recorded_time_)
756    first_recorded_time_ = visit_info.visit_time;
757
758  // Broadcast a notification of the visit.
759  if (visit_id) {
760    if (typed_url_syncable_service_.get())
761      typed_url_syncable_service_->OnUrlVisited(transition, &url_info);
762
763    scoped_ptr<URLVisitedDetails> details(new URLVisitedDetails);
764    details->transition = transition;
765    details->row = url_info;
766    details->visit_time = time;
767    // TODO(meelapshah) Disabled due to potential PageCycler regression.
768    // Re-enable this.
769    // GetMostRecentRedirectsTo(url, &details->redirects);
770    BroadcastNotifications(chrome::NOTIFICATION_HISTORY_URL_VISITED,
771                           details.PassAs<HistoryDetails>());
772  } else {
773    VLOG(0) << "Failed to build visit insert statement:  "
774            << "url_id = " << url_id;
775  }
776
777  return std::make_pair(url_id, visit_id);
778}
779
780void HistoryBackend::AddPagesWithDetails(const URLRows& urls,
781                                         VisitSource visit_source) {
782  if (!db_)
783    return;
784
785  scoped_ptr<URLsModifiedDetails> modified(new URLsModifiedDetails);
786  for (URLRows::const_iterator i = urls.begin(); i != urls.end(); ++i) {
787    DCHECK(!i->last_visit().is_null());
788
789    // As of M37, we no longer maintain an archived database, ignore old visits.
790    if (IsExpiredVisitTime(i->last_visit()))
791      continue;
792
793    URLRow existing_url;
794    URLID url_id = db_->GetRowForURL(i->url(), &existing_url);
795    if (!url_id) {
796      // Add the page if it doesn't exist.
797      url_id = db_->AddURL(*i);
798      if (!url_id) {
799        NOTREACHED() << "Could not add row to DB";
800        return;
801      }
802
803      modified->changed_urls.push_back(*i);
804      modified->changed_urls.back().set_id(url_id);  // i->id_ is likely 0.
805    }
806
807    // Sync code manages the visits itself.
808    if (visit_source != SOURCE_SYNCED) {
809      // Make up a visit to correspond to the last visit to the page.
810      VisitRow visit_info(url_id, i->last_visit(), 0,
811                          content::PageTransitionFromInt(
812                              content::PAGE_TRANSITION_LINK |
813                              content::PAGE_TRANSITION_CHAIN_START |
814                              content::PAGE_TRANSITION_CHAIN_END), 0);
815      if (!db_->AddVisit(&visit_info, visit_source)) {
816        NOTREACHED() << "Adding visit failed.";
817        return;
818      }
819      NotifyVisitObservers(visit_info);
820
821      if (visit_info.visit_time < first_recorded_time_)
822        first_recorded_time_ = visit_info.visit_time;
823    }
824  }
825
826  if (typed_url_syncable_service_.get())
827    typed_url_syncable_service_->OnUrlsModified(&modified->changed_urls);
828
829  // Broadcast a notification for typed URLs that have been modified. This
830  // will be picked up by the in-memory URL database on the main thread.
831  //
832  // TODO(brettw) bug 1140015: Add an "add page" notification so the history
833  // views can keep in sync.
834  BroadcastNotifications(chrome::NOTIFICATION_HISTORY_URLS_MODIFIED,
835                         modified.PassAs<HistoryDetails>());
836
837  ScheduleCommit();
838}
839
840bool HistoryBackend::IsExpiredVisitTime(const base::Time& time) {
841  return time < expirer_.GetCurrentExpirationTime();
842}
843
844void HistoryBackend::SetPageTitle(const GURL& url,
845                                  const base::string16& title) {
846  if (!db_)
847    return;
848
849  // Search for recent redirects which should get the same title. We make a
850  // dummy list containing the exact URL visited if there are no redirects so
851  // the processing below can be the same.
852  history::RedirectList dummy_list;
853  history::RedirectList* redirects;
854  RedirectCache::iterator iter = recent_redirects_.Get(url);
855  if (iter != recent_redirects_.end()) {
856    redirects = &iter->second;
857
858    // This redirect chain should have the destination URL as the last item.
859    DCHECK(!redirects->empty());
860    DCHECK(redirects->back() == url);
861  } else {
862    // No redirect chain stored, make up one containing the URL we want so we
863    // can use the same logic below.
864    dummy_list.push_back(url);
865    redirects = &dummy_list;
866  }
867
868  scoped_ptr<URLsModifiedDetails> details(new URLsModifiedDetails);
869  for (size_t i = 0; i < redirects->size(); i++) {
870    URLRow row;
871    URLID row_id = db_->GetRowForURL(redirects->at(i), &row);
872    if (row_id && row.title() != title) {
873      row.set_title(title);
874      db_->UpdateURLRow(row_id, row);
875      details->changed_urls.push_back(row);
876    }
877  }
878
879  // Broadcast notifications for any URLs that have changed. This will
880  // update the in-memory database and the InMemoryURLIndex.
881  if (!details->changed_urls.empty()) {
882    if (typed_url_syncable_service_.get())
883      typed_url_syncable_service_->OnUrlsModified(&details->changed_urls);
884    BroadcastNotifications(chrome::NOTIFICATION_HISTORY_URLS_MODIFIED,
885                           details.PassAs<HistoryDetails>());
886    ScheduleCommit();
887  }
888}
889
890void HistoryBackend::AddPageNoVisitForBookmark(const GURL& url,
891                                               const base::string16& title) {
892  if (!db_)
893    return;
894
895  URLRow url_info(url);
896  URLID url_id = db_->GetRowForURL(url, &url_info);
897  if (url_id) {
898    // URL is already known, nothing to do.
899    return;
900  }
901
902  if (!title.empty()) {
903    url_info.set_title(title);
904  } else {
905    url_info.set_title(base::UTF8ToUTF16(url.spec()));
906  }
907
908  url_info.set_last_visit(Time::Now());
909  // Mark the page hidden. If the user types it in, it'll unhide.
910  url_info.set_hidden(true);
911
912  db_->AddURL(url_info);
913}
914
915void HistoryBackend::IterateURLs(
916    const scoped_refptr<visitedlink::VisitedLinkDelegate::URLEnumerator>&
917    iterator) {
918  if (db_) {
919    HistoryDatabase::URLEnumerator e;
920    if (db_->InitURLEnumeratorForEverything(&e)) {
921      URLRow info;
922      while (e.GetNextURL(&info)) {
923        iterator->OnURL(info.url());
924      }
925      iterator->OnComplete(true);  // Success.
926      return;
927    }
928  }
929  iterator->OnComplete(false);  // Failure.
930}
931
932bool HistoryBackend::GetAllTypedURLs(URLRows* urls) {
933  if (db_)
934    return db_->GetAllTypedUrls(urls);
935  return false;
936}
937
938bool HistoryBackend::GetVisitsForURL(URLID id, VisitVector* visits) {
939  if (db_)
940    return db_->GetVisitsForURL(id, visits);
941  return false;
942}
943
944bool HistoryBackend::GetMostRecentVisitsForURL(URLID id,
945                                               int max_visits,
946                                               VisitVector* visits) {
947  if (db_)
948    return db_->GetMostRecentVisitsForURL(id, max_visits, visits);
949  return false;
950}
951
952bool HistoryBackend::UpdateURL(URLID id, const history::URLRow& url) {
953  if (db_)
954    return db_->UpdateURLRow(id, url);
955  return false;
956}
957
958bool HistoryBackend::AddVisits(const GURL& url,
959                               const std::vector<VisitInfo>& visits,
960                               VisitSource visit_source) {
961  if (db_) {
962    for (std::vector<VisitInfo>::const_iterator visit = visits.begin();
963         visit != visits.end(); ++visit) {
964      if (!AddPageVisit(
965              url, visit->first, 0, visit->second, visit_source).first) {
966        return false;
967      }
968    }
969    ScheduleCommit();
970    return true;
971  }
972  return false;
973}
974
975bool HistoryBackend::RemoveVisits(const VisitVector& visits) {
976  if (!db_)
977    return false;
978
979  expirer_.ExpireVisits(visits);
980  ScheduleCommit();
981  return true;
982}
983
984bool HistoryBackend::GetVisitsSource(const VisitVector& visits,
985                                     VisitSourceMap* sources) {
986  if (!db_)
987    return false;
988
989  db_->GetVisitsSource(visits, sources);
990  return true;
991}
992
993bool HistoryBackend::GetURL(const GURL& url, history::URLRow* url_row) {
994  if (db_)
995    return db_->GetRowForURL(url, url_row) != 0;
996  return false;
997}
998
999HistoryBackend::QueryURLResult HistoryBackend::QueryURL(const GURL& url,
1000                                                        bool want_visits) {
1001  QueryURLResult result;
1002  result.success = db_ && db_->GetRowForURL(url, &result.row);
1003  // Optionally query the visits.
1004  if (result.success && want_visits)
1005    db_->GetVisitsForURL(result.row.id(), &result.visits);
1006  return result;
1007}
1008
1009TypedUrlSyncableService* HistoryBackend::GetTypedUrlSyncableService() const {
1010  return typed_url_syncable_service_.get();
1011}
1012
1013// Segment usage ---------------------------------------------------------------
1014
1015void HistoryBackend::DeleteOldSegmentData() {
1016  if (db_)
1017    db_->DeleteSegmentData(Time::Now() -
1018                           TimeDelta::FromDays(kSegmentDataRetention));
1019}
1020
1021void HistoryBackend::QuerySegmentUsage(
1022    scoped_refptr<QuerySegmentUsageRequest> request,
1023    const Time from_time,
1024    int max_result_count) {
1025  if (request->canceled())
1026    return;
1027
1028  if (db_) {
1029    db_->QuerySegmentUsage(from_time, max_result_count, &request->value.get());
1030
1031    // If this is the first time we query segments, invoke
1032    // DeleteOldSegmentData asynchronously. We do this to cleanup old
1033    // entries.
1034    if (!segment_queried_) {
1035      segment_queried_ = true;
1036      base::MessageLoop::current()->PostTask(
1037          FROM_HERE,
1038          base::Bind(&HistoryBackend::DeleteOldSegmentData, this));
1039    }
1040  }
1041  request->ForwardResult(request->handle(), &request->value.get());
1042}
1043
1044// Keyword visits --------------------------------------------------------------
1045
1046void HistoryBackend::SetKeywordSearchTermsForURL(const GURL& url,
1047                                                 TemplateURLID keyword_id,
1048                                                 const base::string16& term) {
1049  if (!db_)
1050    return;
1051
1052  // Get the ID for this URL.
1053  URLRow row;
1054  if (!db_->GetRowForURL(url, &row)) {
1055    // There is a small possibility the url was deleted before the keyword
1056    // was added. Ignore the request.
1057    return;
1058  }
1059
1060  db_->SetKeywordSearchTermsForURL(row.id(), keyword_id, term);
1061
1062  BroadcastNotifications(
1063      chrome::NOTIFICATION_HISTORY_KEYWORD_SEARCH_TERM_UPDATED,
1064      scoped_ptr<HistoryDetails>(
1065          new KeywordSearchUpdatedDetails(row, keyword_id, term)));
1066  ScheduleCommit();
1067}
1068
1069void HistoryBackend::DeleteAllSearchTermsForKeyword(
1070    TemplateURLID keyword_id) {
1071  if (!db_)
1072    return;
1073
1074  db_->DeleteAllSearchTermsForKeyword(keyword_id);
1075  ScheduleCommit();
1076}
1077
1078void HistoryBackend::GetMostRecentKeywordSearchTerms(
1079    scoped_refptr<GetMostRecentKeywordSearchTermsRequest> request,
1080    TemplateURLID keyword_id,
1081    const base::string16& prefix,
1082    int max_count) {
1083  if (request->canceled())
1084    return;
1085
1086  if (db_) {
1087    db_->GetMostRecentKeywordSearchTerms(keyword_id, prefix, max_count,
1088                                         &(request->value));
1089  }
1090  request->ForwardResult(request->handle(), &request->value);
1091}
1092
1093void HistoryBackend::DeleteKeywordSearchTermForURL(const GURL& url) {
1094  if (!db_)
1095    return;
1096
1097  URLID url_id = db_->GetRowForURL(url, NULL);
1098  if (!url_id)
1099    return;
1100  db_->DeleteKeywordSearchTermForURL(url_id);
1101
1102  BroadcastNotifications(
1103      chrome::NOTIFICATION_HISTORY_KEYWORD_SEARCH_TERM_DELETED,
1104      scoped_ptr<HistoryDetails>(new KeywordSearchDeletedDetails(url_id)));
1105  ScheduleCommit();
1106}
1107
1108void HistoryBackend::DeleteMatchingURLsForKeyword(TemplateURLID keyword_id,
1109                                                  const base::string16& term) {
1110  if (!db_)
1111    return;
1112
1113  std::vector<KeywordSearchTermRow> rows;
1114  if (db_->GetKeywordSearchTermRows(term, &rows)) {
1115    std::vector<GURL> items_to_delete;
1116    URLRow row;
1117    for (std::vector<KeywordSearchTermRow>::iterator it = rows.begin();
1118         it != rows.end(); ++it) {
1119      if ((it->keyword_id == keyword_id) && db_->GetURLRow(it->url_id, &row))
1120        items_to_delete.push_back(row.url());
1121    }
1122    DeleteURLs(items_to_delete);
1123  }
1124}
1125
1126// Downloads -------------------------------------------------------------------
1127
1128uint32 HistoryBackend::GetNextDownloadId() {
1129  return db_ ? db_->GetNextDownloadId() : content::DownloadItem::kInvalidId;
1130}
1131
1132// Get all the download entries from the database.
1133void HistoryBackend::QueryDownloads(std::vector<DownloadRow>* rows) {
1134  if (db_)
1135    db_->QueryDownloads(rows);
1136}
1137
1138// Update a particular download entry.
1139void HistoryBackend::UpdateDownload(const history::DownloadRow& data) {
1140  if (!db_)
1141    return;
1142  db_->UpdateDownload(data);
1143  ScheduleCommit();
1144}
1145
1146bool HistoryBackend::CreateDownload(const history::DownloadRow& history_info) {
1147  if (!db_)
1148    return false;
1149  bool success = db_->CreateDownload(history_info);
1150  ScheduleCommit();
1151  return success;
1152}
1153
1154void HistoryBackend::RemoveDownloads(const std::set<uint32>& ids) {
1155  if (!db_)
1156    return;
1157  size_t downloads_count_before = db_->CountDownloads();
1158  base::TimeTicks started_removing = base::TimeTicks::Now();
1159  // HistoryBackend uses a long-running Transaction that is committed
1160  // periodically, so this loop doesn't actually hit the disk too hard.
1161  for (std::set<uint32>::const_iterator it = ids.begin();
1162       it != ids.end(); ++it) {
1163    db_->RemoveDownload(*it);
1164  }
1165  ScheduleCommit();
1166  base::TimeTicks finished_removing = base::TimeTicks::Now();
1167  size_t downloads_count_after = db_->CountDownloads();
1168
1169  DCHECK_LE(downloads_count_after, downloads_count_before);
1170  if (downloads_count_after > downloads_count_before)
1171    return;
1172  size_t num_downloads_deleted = downloads_count_before - downloads_count_after;
1173  UMA_HISTOGRAM_COUNTS("Download.DatabaseRemoveDownloadsCount",
1174                        num_downloads_deleted);
1175  base::TimeDelta micros = (1000 * (finished_removing - started_removing));
1176  UMA_HISTOGRAM_TIMES("Download.DatabaseRemoveDownloadsTime", micros);
1177  if (num_downloads_deleted > 0) {
1178    UMA_HISTOGRAM_TIMES("Download.DatabaseRemoveDownloadsTimePerRecord",
1179                        (1000 * micros) / num_downloads_deleted);
1180  }
1181  DCHECK_GE(ids.size(), num_downloads_deleted);
1182  if (ids.size() < num_downloads_deleted)
1183    return;
1184  UMA_HISTOGRAM_COUNTS("Download.DatabaseRemoveDownloadsCountNotRemoved",
1185                        ids.size() - num_downloads_deleted);
1186}
1187
1188void HistoryBackend::QueryHistory(scoped_refptr<QueryHistoryRequest> request,
1189                                  const base::string16& text_query,
1190                                  const QueryOptions& options) {
1191  if (request->canceled())
1192    return;
1193
1194  TimeTicks beginning_time = TimeTicks::Now();
1195
1196  if (db_) {
1197    if (text_query.empty()) {
1198      // Basic history query for the main database.
1199      QueryHistoryBasic(options, &request->value);
1200    } else {
1201      // Text history query.
1202      QueryHistoryText(text_query, options, &request->value);
1203    }
1204  }
1205
1206  request->ForwardResult(request->handle(), &request->value);
1207
1208  UMA_HISTOGRAM_TIMES("History.QueryHistory",
1209                      TimeTicks::Now() - beginning_time);
1210}
1211
1212// Basic time-based querying of history.
1213void HistoryBackend::QueryHistoryBasic(const QueryOptions& options,
1214                                       QueryResults* result) {
1215  // First get all visits.
1216  VisitVector visits;
1217  bool has_more_results = db_->GetVisibleVisitsInRange(options, &visits);
1218  DCHECK(static_cast<int>(visits.size()) <= options.EffectiveMaxCount());
1219
1220  // Now add them and the URL rows to the results.
1221  URLResult url_result;
1222  for (size_t i = 0; i < visits.size(); i++) {
1223    const VisitRow visit = visits[i];
1224
1225    // Add a result row for this visit, get the URL info from the DB.
1226    if (!db_->GetURLRow(visit.url_id, &url_result)) {
1227      VLOG(0) << "Failed to get id " << visit.url_id
1228              << " from history.urls.";
1229      continue;  // DB out of sync and URL doesn't exist, try to recover.
1230    }
1231
1232    if (!url_result.url().is_valid()) {
1233      VLOG(0) << "Got invalid URL from history.urls with id "
1234              << visit.url_id << ":  "
1235              << url_result.url().possibly_invalid_spec();
1236      continue;  // Don't report invalid URLs in case of corruption.
1237    }
1238
1239    url_result.set_visit_time(visit.visit_time);
1240
1241    // Set whether the visit was blocked for a managed user by looking at the
1242    // transition type.
1243    url_result.set_blocked_visit(
1244        (visit.transition & content::PAGE_TRANSITION_BLOCKED) != 0);
1245
1246    // We don't set any of the query-specific parts of the URLResult, since
1247    // snippets and stuff don't apply to basic querying.
1248    result->AppendURLBySwapping(&url_result);
1249  }
1250
1251  if (!has_more_results && options.begin_time <= first_recorded_time_)
1252    result->set_reached_beginning(true);
1253}
1254
1255// Text-based querying of history.
1256void HistoryBackend::QueryHistoryText(const base::string16& text_query,
1257                                      const QueryOptions& options,
1258                                      QueryResults* result) {
1259  URLRows text_matches;
1260  db_->GetTextMatches(text_query, &text_matches);
1261
1262  std::vector<URLResult> matching_visits;
1263  VisitVector visits;    // Declare outside loop to prevent re-construction.
1264  for (size_t i = 0; i < text_matches.size(); i++) {
1265    const URLRow& text_match = text_matches[i];
1266    // Get all visits for given URL match.
1267    db_->GetVisibleVisitsForURL(text_match.id(), options, &visits);
1268    for (size_t j = 0; j < visits.size(); j++) {
1269      URLResult url_result(text_match);
1270      url_result.set_visit_time(visits[j].visit_time);
1271      matching_visits.push_back(url_result);
1272    }
1273  }
1274
1275  std::sort(matching_visits.begin(), matching_visits.end(),
1276            URLResult::CompareVisitTime);
1277
1278  size_t max_results = options.max_count == 0 ?
1279      std::numeric_limits<size_t>::max() : static_cast<int>(options.max_count);
1280  for (std::vector<URLResult>::iterator it = matching_visits.begin();
1281       it != matching_visits.end() && result->size() < max_results; ++it) {
1282    result->AppendURLBySwapping(&(*it));
1283  }
1284
1285  if (matching_visits.size() == result->size() &&
1286      options.begin_time <= first_recorded_time_)
1287    result->set_reached_beginning(true);
1288}
1289
1290// Frontend to GetMostRecentRedirectsFrom from the history thread.
1291void HistoryBackend::QueryRedirectsFrom(
1292    scoped_refptr<QueryRedirectsRequest> request,
1293    const GURL& url) {
1294  if (request->canceled())
1295    return;
1296  bool success = GetMostRecentRedirectsFrom(url, &request->value);
1297  request->ForwardResult(request->handle(), url, success, &request->value);
1298}
1299
1300void HistoryBackend::QueryRedirectsTo(
1301    scoped_refptr<QueryRedirectsRequest> request,
1302    const GURL& url) {
1303  if (request->canceled())
1304    return;
1305  bool success = GetMostRecentRedirectsTo(url, &request->value);
1306  request->ForwardResult(request->handle(), url, success, &request->value);
1307}
1308
1309void HistoryBackend::GetVisibleVisitCountToHost(
1310    scoped_refptr<GetVisibleVisitCountToHostRequest> request,
1311    const GURL& url) {
1312  if (request->canceled())
1313    return;
1314  int count = 0;
1315  Time first_visit;
1316  const bool success = db_.get() &&
1317      db_->GetVisibleVisitCountToHost(url, &count, &first_visit);
1318  request->ForwardResult(request->handle(), success, count, first_visit);
1319}
1320
1321void HistoryBackend::QueryTopURLsAndRedirects(
1322    scoped_refptr<QueryTopURLsAndRedirectsRequest> request,
1323    int result_count) {
1324  if (request->canceled())
1325    return;
1326
1327  if (!db_) {
1328    request->ForwardResult(request->handle(), false, NULL, NULL);
1329    return;
1330  }
1331
1332  std::vector<GURL>* top_urls = &request->value.a;
1333  history::RedirectMap* redirects = &request->value.b;
1334
1335  ScopedVector<PageUsageData> data;
1336  db_->QuerySegmentUsage(base::Time::Now() - base::TimeDelta::FromDays(90),
1337      result_count, &data.get());
1338
1339  for (size_t i = 0; i < data.size(); ++i) {
1340    top_urls->push_back(data[i]->GetURL());
1341    RefCountedVector<GURL>* list = new RefCountedVector<GURL>;
1342    GetMostRecentRedirectsFrom(top_urls->back(), &list->data);
1343    (*redirects)[top_urls->back()] = list;
1344  }
1345
1346  request->ForwardResult(request->handle(), true, top_urls, redirects);
1347}
1348
1349// Will replace QueryTopURLsAndRedirectsRequest.
1350void HistoryBackend::QueryMostVisitedURLs(
1351    scoped_refptr<QueryMostVisitedURLsRequest> request,
1352    int result_count,
1353    int days_back) {
1354  if (request->canceled())
1355    return;
1356
1357  if (!db_) {
1358    // No History Database - return an empty list.
1359    request->ForwardResult(request->handle(), MostVisitedURLList());
1360    return;
1361  }
1362
1363  MostVisitedURLList* result = &request->value;
1364  QueryMostVisitedURLsImpl(result_count, days_back, result);
1365  request->ForwardResult(request->handle(), *result);
1366}
1367
1368void HistoryBackend::QueryFilteredURLs(
1369      scoped_refptr<QueryFilteredURLsRequest> request,
1370      int result_count,
1371      const history::VisitFilter& filter,
1372      bool extended_info)  {
1373  if (request->canceled())
1374    return;
1375
1376  base::Time request_start = base::Time::Now();
1377
1378  if (!db_) {
1379    // No History Database - return an empty list.
1380    request->ForwardResult(request->handle(), FilteredURLList());
1381    return;
1382  }
1383
1384  VisitVector visits;
1385  db_->GetDirectVisitsDuringTimes(filter, 0, &visits);
1386
1387  std::map<URLID, double> score_map;
1388  for (size_t i = 0; i < visits.size(); ++i) {
1389    score_map[visits[i].url_id] += filter.GetVisitScore(visits[i]);
1390  }
1391
1392  // TODO(georgey): experiment with visit_segment database granularity (it is
1393  // currently 24 hours) to use it directly instead of using visits database,
1394  // which is considerably slower.
1395  ScopedVector<PageUsageData> data;
1396  data.reserve(score_map.size());
1397  for (std::map<URLID, double>::iterator it = score_map.begin();
1398       it != score_map.end(); ++it) {
1399    PageUsageData* pud = new PageUsageData(it->first);
1400    pud->SetScore(it->second);
1401    data.push_back(pud);
1402  }
1403
1404  // Limit to the top |result_count| results.
1405  std::sort(data.begin(), data.end(), PageUsageData::Predicate);
1406  if (result_count && implicit_cast<int>(data.size()) > result_count)
1407    data.resize(result_count);
1408
1409  for (size_t i = 0; i < data.size(); ++i) {
1410    URLRow info;
1411    if (db_->GetURLRow(data[i]->GetID(), &info)) {
1412      data[i]->SetURL(info.url());
1413      data[i]->SetTitle(info.title());
1414    }
1415  }
1416
1417  FilteredURLList& result = request->value;
1418  for (size_t i = 0; i < data.size(); ++i) {
1419    PageUsageData* current_data = data[i];
1420    FilteredURL url(*current_data);
1421
1422    if (extended_info) {
1423      VisitVector visits;
1424      db_->GetVisitsForURL(current_data->GetID(), &visits);
1425      if (visits.size() > 0) {
1426        url.extended_info.total_visits = visits.size();
1427        for (size_t i = 0; i < visits.size(); ++i) {
1428          url.extended_info.duration_opened +=
1429              visits[i].visit_duration.InSeconds();
1430          if (visits[i].visit_time > url.extended_info.last_visit_time) {
1431            url.extended_info.last_visit_time = visits[i].visit_time;
1432          }
1433        }
1434        // TODO(macourteau): implement the url.extended_info.visits stat.
1435      }
1436    }
1437    result.push_back(url);
1438  }
1439
1440  int delta_time = std::max(1, std::min(999,
1441      static_cast<int>((base::Time::Now() - request_start).InMilliseconds())));
1442  STATIC_HISTOGRAM_POINTER_BLOCK(
1443      "NewTabPage.SuggestedSitesLoadTime",
1444      Add(delta_time),
1445      base::LinearHistogram::FactoryGet("NewTabPage.SuggestedSitesLoadTime",
1446          1, 1000, 100, base::Histogram::kUmaTargetedHistogramFlag));
1447
1448  request->ForwardResult(request->handle(), result);
1449}
1450
1451void HistoryBackend::QueryMostVisitedURLsImpl(int result_count,
1452                                              int days_back,
1453                                              MostVisitedURLList* result) {
1454  if (!db_)
1455    return;
1456
1457  ScopedVector<PageUsageData> data;
1458  db_->QuerySegmentUsage(base::Time::Now() -
1459                         base::TimeDelta::FromDays(days_back),
1460                         result_count, &data.get());
1461
1462  for (size_t i = 0; i < data.size(); ++i) {
1463    PageUsageData* current_data = data[i];
1464    RedirectList redirects;
1465    GetMostRecentRedirectsFrom(current_data->GetURL(), &redirects);
1466    MostVisitedURL url = MakeMostVisitedURL(*current_data, redirects);
1467    result->push_back(url);
1468  }
1469}
1470
1471void HistoryBackend::GetRedirectsFromSpecificVisit(
1472    VisitID cur_visit, history::RedirectList* redirects) {
1473  // Follow any redirects from the given visit and add them to the list.
1474  // It *should* be impossible to get a circular chain here, but we check
1475  // just in case to avoid infinite loops.
1476  GURL cur_url;
1477  std::set<VisitID> visit_set;
1478  visit_set.insert(cur_visit);
1479  while (db_->GetRedirectFromVisit(cur_visit, &cur_visit, &cur_url)) {
1480    if (visit_set.find(cur_visit) != visit_set.end()) {
1481      NOTREACHED() << "Loop in visit chain, giving up";
1482      return;
1483    }
1484    visit_set.insert(cur_visit);
1485    redirects->push_back(cur_url);
1486  }
1487}
1488
1489void HistoryBackend::GetRedirectsToSpecificVisit(
1490    VisitID cur_visit,
1491    history::RedirectList* redirects) {
1492  // Follow redirects going to cur_visit. These are added to |redirects| in
1493  // the order they are found. If a redirect chain looks like A -> B -> C and
1494  // |cur_visit| = C, redirects will be {B, A} in that order.
1495  if (!db_)
1496    return;
1497
1498  GURL cur_url;
1499  std::set<VisitID> visit_set;
1500  visit_set.insert(cur_visit);
1501  while (db_->GetRedirectToVisit(cur_visit, &cur_visit, &cur_url)) {
1502    if (visit_set.find(cur_visit) != visit_set.end()) {
1503      NOTREACHED() << "Loop in visit chain, giving up";
1504      return;
1505    }
1506    visit_set.insert(cur_visit);
1507    redirects->push_back(cur_url);
1508  }
1509}
1510
1511bool HistoryBackend::GetMostRecentRedirectsFrom(
1512    const GURL& from_url,
1513    history::RedirectList* redirects) {
1514  redirects->clear();
1515  if (!db_)
1516    return false;
1517
1518  URLID from_url_id = db_->GetRowForURL(from_url, NULL);
1519  VisitID cur_visit = db_->GetMostRecentVisitForURL(from_url_id, NULL);
1520  if (!cur_visit)
1521    return false;  // No visits for URL.
1522
1523  GetRedirectsFromSpecificVisit(cur_visit, redirects);
1524  return true;
1525}
1526
1527bool HistoryBackend::GetMostRecentRedirectsTo(
1528    const GURL& to_url,
1529    history::RedirectList* redirects) {
1530  redirects->clear();
1531  if (!db_)
1532    return false;
1533
1534  URLID to_url_id = db_->GetRowForURL(to_url, NULL);
1535  VisitID cur_visit = db_->GetMostRecentVisitForURL(to_url_id, NULL);
1536  if (!cur_visit)
1537    return false;  // No visits for URL.
1538
1539  GetRedirectsToSpecificVisit(cur_visit, redirects);
1540  return true;
1541}
1542
1543void HistoryBackend::ScheduleAutocomplete(HistoryURLProvider* provider,
1544                                          HistoryURLProviderParams* params) {
1545  // ExecuteWithDB should handle the NULL database case.
1546  provider->ExecuteWithDB(this, db_.get(), params);
1547}
1548
1549void HistoryBackend::DeleteFTSIndexDatabases() {
1550  // Find files on disk matching the text databases file pattern so we can
1551  // quickly test for and delete them.
1552  base::FilePath::StringType filepattern =
1553      FILE_PATH_LITERAL("History Index *");
1554  base::FileEnumerator enumerator(
1555      history_dir_, false, base::FileEnumerator::FILES, filepattern);
1556  int num_databases_deleted = 0;
1557  base::FilePath current_file;
1558  while (!(current_file = enumerator.Next()).empty()) {
1559    if (sql::Connection::Delete(current_file))
1560      num_databases_deleted++;
1561  }
1562  UMA_HISTOGRAM_COUNTS("History.DeleteFTSIndexDatabases",
1563                       num_databases_deleted);
1564}
1565
1566void HistoryBackend::GetFavicons(
1567    const std::vector<GURL>& icon_urls,
1568    int icon_types,
1569    int desired_size_in_dip,
1570    const std::vector<ui::ScaleFactor>& desired_scale_factors,
1571    std::vector<favicon_base::FaviconRawBitmapResult>* bitmap_results) {
1572  UpdateFaviconMappingsAndFetchImpl(NULL, icon_urls, icon_types,
1573                                    desired_size_in_dip, desired_scale_factors,
1574                                    bitmap_results);
1575}
1576
1577void HistoryBackend::GetLargestFaviconForURL(
1578    const GURL& page_url,
1579    const std::vector<int>& icon_types,
1580    int minimum_size_in_pixels,
1581    favicon_base::FaviconRawBitmapResult* favicon_bitmap_result) {
1582  DCHECK(favicon_bitmap_result);
1583
1584  if (!db_ || !thumbnail_db_)
1585    return;
1586
1587  TimeTicks beginning_time = TimeTicks::Now();
1588
1589  std::vector<IconMapping> icon_mappings;
1590  if (!thumbnail_db_->GetIconMappingsForPageURL(page_url, &icon_mappings) ||
1591      icon_mappings.empty())
1592    return;
1593
1594  int required_icon_types = 0;
1595  for (std::vector<int>::const_iterator i = icon_types.begin();
1596       i != icon_types.end(); ++i) {
1597    required_icon_types |= *i;
1598  }
1599
1600  // Find the largest bitmap for each IconType placing in
1601  // |largest_favicon_bitmaps|.
1602  std::map<favicon_base::IconType, FaviconBitmap> largest_favicon_bitmaps;
1603  for (std::vector<IconMapping>::const_iterator i = icon_mappings.begin();
1604       i != icon_mappings.end(); ++i) {
1605    if (!(i->icon_type & required_icon_types))
1606      continue;
1607    std::vector<FaviconBitmapIDSize> bitmap_id_sizes;
1608    thumbnail_db_->GetFaviconBitmapIDSizes(i->icon_id, &bitmap_id_sizes);
1609    FaviconBitmap& largest = largest_favicon_bitmaps[i->icon_type];
1610    for (std::vector<FaviconBitmapIDSize>::const_iterator j =
1611             bitmap_id_sizes.begin(); j != bitmap_id_sizes.end(); ++j) {
1612      if (largest.bitmap_id == 0 ||
1613          (largest.pixel_size.width() < j->pixel_size.width() &&
1614           largest.pixel_size.height() < j->pixel_size.height())) {
1615        largest.icon_id = i->icon_id;
1616        largest.bitmap_id = j->bitmap_id;
1617        largest.pixel_size = j->pixel_size;
1618      }
1619    }
1620  }
1621  if (largest_favicon_bitmaps.empty())
1622    return;
1623
1624  // Find an icon which is larger than minimum_size_in_pixels in the order of
1625  // icon_types.
1626  FaviconBitmap largest_icon;
1627  for (std::vector<int>::const_iterator t = icon_types.begin();
1628       t != icon_types.end(); ++t) {
1629    for (std::map<favicon_base::IconType, FaviconBitmap>::const_iterator f =
1630             largest_favicon_bitmaps.begin();
1631         f != largest_favicon_bitmaps.end();
1632         ++f) {
1633      if (f->first & *t &&
1634          (largest_icon.bitmap_id == 0 ||
1635           (largest_icon.pixel_size.height() < f->second.pixel_size.height() &&
1636            largest_icon.pixel_size.width() < f->second.pixel_size.width()))) {
1637        largest_icon = f->second;
1638      }
1639    }
1640    if (largest_icon.pixel_size.width() > minimum_size_in_pixels &&
1641        largest_icon.pixel_size.height() > minimum_size_in_pixels)
1642      break;
1643  }
1644
1645  GURL icon_url;
1646  favicon_base::IconType icon_type;
1647  if (!thumbnail_db_->GetFaviconHeader(largest_icon.icon_id, &icon_url,
1648                                       &icon_type)) {
1649    return;
1650  }
1651
1652  base::Time last_updated;
1653  favicon_base::FaviconRawBitmapResult bitmap_result;
1654  bitmap_result.icon_url = icon_url;
1655  bitmap_result.icon_type = icon_type;
1656  if (!thumbnail_db_->GetFaviconBitmap(largest_icon.bitmap_id,
1657                                       &last_updated,
1658                                       &bitmap_result.bitmap_data,
1659                                       &bitmap_result.pixel_size)) {
1660    return;
1661  }
1662
1663  bitmap_result.expired = (Time::Now() - last_updated) >
1664      TimeDelta::FromDays(kFaviconRefetchDays);
1665  if (bitmap_result.is_valid())
1666    *favicon_bitmap_result = bitmap_result;
1667
1668  HISTOGRAM_TIMES("History.GetLargestFaviconForURL",
1669                  TimeTicks::Now() - beginning_time);
1670}
1671
1672void HistoryBackend::GetFaviconsForURL(
1673    const GURL& page_url,
1674    int icon_types,
1675    int desired_size_in_dip,
1676    const std::vector<ui::ScaleFactor>& desired_scale_factors,
1677    std::vector<favicon_base::FaviconRawBitmapResult>* bitmap_results) {
1678  DCHECK(bitmap_results);
1679  GetFaviconsFromDB(page_url, icon_types, desired_size_in_dip,
1680                    desired_scale_factors, bitmap_results);
1681}
1682
1683void HistoryBackend::GetFaviconForID(
1684    favicon_base::FaviconID favicon_id,
1685    int desired_size_in_dip,
1686    ui::ScaleFactor desired_scale_factor,
1687    std::vector<favicon_base::FaviconRawBitmapResult>* bitmap_results) {
1688  std::vector<favicon_base::FaviconID> favicon_ids;
1689  favicon_ids.push_back(favicon_id);
1690  std::vector<ui::ScaleFactor> desired_scale_factors;
1691  desired_scale_factors.push_back(desired_scale_factor);
1692
1693  // Get results from DB.
1694  GetFaviconBitmapResultsForBestMatch(favicon_ids,
1695                                      desired_size_in_dip,
1696                                      desired_scale_factors,
1697                                      bitmap_results);
1698}
1699
1700void HistoryBackend::UpdateFaviconMappingsAndFetch(
1701    const GURL& page_url,
1702    const std::vector<GURL>& icon_urls,
1703    int icon_types,
1704    int desired_size_in_dip,
1705    const std::vector<ui::ScaleFactor>& desired_scale_factors,
1706    std::vector<favicon_base::FaviconRawBitmapResult>* bitmap_results) {
1707  UpdateFaviconMappingsAndFetchImpl(&page_url, icon_urls, icon_types,
1708                                    desired_size_in_dip, desired_scale_factors,
1709                                    bitmap_results);
1710}
1711
1712void HistoryBackend::MergeFavicon(
1713    const GURL& page_url,
1714    const GURL& icon_url,
1715    favicon_base::IconType icon_type,
1716    scoped_refptr<base::RefCountedMemory> bitmap_data,
1717    const gfx::Size& pixel_size) {
1718  if (!thumbnail_db_ || !db_)
1719    return;
1720
1721  favicon_base::FaviconID favicon_id =
1722      thumbnail_db_->GetFaviconIDForFaviconURL(icon_url, icon_type, NULL);
1723
1724  if (!favicon_id) {
1725    // There is no favicon at |icon_url|, create it.
1726    favicon_id = thumbnail_db_->AddFavicon(icon_url, icon_type);
1727  }
1728
1729  std::vector<FaviconBitmapIDSize> bitmap_id_sizes;
1730  thumbnail_db_->GetFaviconBitmapIDSizes(favicon_id, &bitmap_id_sizes);
1731
1732  // If there is already a favicon bitmap of |pixel_size| at |icon_url|,
1733  // replace it.
1734  bool bitmap_identical = false;
1735  bool replaced_bitmap = false;
1736  for (size_t i = 0; i < bitmap_id_sizes.size(); ++i) {
1737    if (bitmap_id_sizes[i].pixel_size == pixel_size) {
1738      if (IsFaviconBitmapDataEqual(bitmap_id_sizes[i].bitmap_id, bitmap_data)) {
1739        thumbnail_db_->SetFaviconBitmapLastUpdateTime(
1740            bitmap_id_sizes[i].bitmap_id, base::Time::Now());
1741        bitmap_identical = true;
1742      } else {
1743        thumbnail_db_->SetFaviconBitmap(bitmap_id_sizes[i].bitmap_id,
1744            bitmap_data, base::Time::Now());
1745        replaced_bitmap = true;
1746      }
1747      break;
1748    }
1749  }
1750
1751  // Create a vector of the pixel sizes of the favicon bitmaps currently at
1752  // |icon_url|.
1753  std::vector<gfx::Size> favicon_sizes;
1754  for (size_t i = 0; i < bitmap_id_sizes.size(); ++i)
1755    favicon_sizes.push_back(bitmap_id_sizes[i].pixel_size);
1756
1757  if (!replaced_bitmap && !bitmap_identical) {
1758    // Set the preexisting favicon bitmaps as expired as the preexisting favicon
1759    // bitmaps are not consistent with the merged in data.
1760    thumbnail_db_->SetFaviconOutOfDate(favicon_id);
1761
1762    // Delete an arbitrary favicon bitmap to avoid going over the limit of
1763    // |kMaxFaviconBitmapsPerIconURL|.
1764    if (bitmap_id_sizes.size() >= kMaxFaviconBitmapsPerIconURL) {
1765      thumbnail_db_->DeleteFaviconBitmap(bitmap_id_sizes[0].bitmap_id);
1766      favicon_sizes.erase(favicon_sizes.begin());
1767    }
1768    thumbnail_db_->AddFaviconBitmap(favicon_id, bitmap_data, base::Time::Now(),
1769                                    pixel_size);
1770    favicon_sizes.push_back(pixel_size);
1771  }
1772
1773  // A site may have changed the favicons that it uses for |page_url|.
1774  // Example Scenario:
1775  //   page_url = news.google.com
1776  //   Initial State: www.google.com/favicon.ico 16x16, 32x32
1777  //   MergeFavicon(news.google.com, news.google.com/news_specific.ico, ...,
1778  //                ..., 16x16)
1779  //
1780  // Difficulties:
1781  // 1. Sync requires that a call to GetFaviconsForURL() returns the
1782  //    |bitmap_data| passed into MergeFavicon().
1783  //    - It is invalid for the 16x16 bitmap for www.google.com/favicon.ico to
1784  //      stay mapped to news.google.com because it would be unclear which 16x16
1785  //      bitmap should be returned via GetFaviconsForURL().
1786  //
1787  // 2. www.google.com/favicon.ico may be mapped to more than just
1788  //    news.google.com (eg www.google.com).
1789  //    - The 16x16 bitmap cannot be deleted from www.google.com/favicon.ico
1790  //
1791  // To resolve these problems, we copy all of the favicon bitmaps previously
1792  // mapped to news.google.com (|page_url|) and add them to the favicon at
1793  // news.google.com/news_specific.ico (|icon_url|). The favicon sizes for
1794  // |icon_url| are set to default to indicate that |icon_url| has incomplete
1795  // / incorrect data.
1796  // Difficulty 1: All but news.google.com/news_specific.ico are unmapped from
1797  //              news.google.com
1798  // Difficulty 2: The favicon bitmaps for www.google.com/favicon.ico are not
1799  //               modified.
1800
1801  std::vector<IconMapping> icon_mappings;
1802  thumbnail_db_->GetIconMappingsForPageURL(page_url, icon_type, &icon_mappings);
1803
1804  // Copy the favicon bitmaps mapped to |page_url| to the favicon at |icon_url|
1805  // till the limit of |kMaxFaviconBitmapsPerIconURL| is reached.
1806  for (size_t i = 0; i < icon_mappings.size(); ++i) {
1807    if (favicon_sizes.size() >= kMaxFaviconBitmapsPerIconURL)
1808      break;
1809
1810    if (icon_mappings[i].icon_url == icon_url)
1811      continue;
1812
1813    std::vector<FaviconBitmap> bitmaps_to_copy;
1814    thumbnail_db_->GetFaviconBitmaps(icon_mappings[i].icon_id,
1815                                     &bitmaps_to_copy);
1816    for (size_t j = 0; j < bitmaps_to_copy.size(); ++j) {
1817      // Do not add a favicon bitmap at a pixel size for which there is already
1818      // a favicon bitmap mapped to |icon_url|. The one there is more correct
1819      // and having multiple equally sized favicon bitmaps for |page_url| is
1820      // ambiguous in terms of GetFaviconsForURL().
1821      std::vector<gfx::Size>::iterator it = std::find(favicon_sizes.begin(),
1822          favicon_sizes.end(), bitmaps_to_copy[j].pixel_size);
1823      if (it != favicon_sizes.end())
1824        continue;
1825
1826      // Add the favicon bitmap as expired as it is not consistent with the
1827      // merged in data.
1828      thumbnail_db_->AddFaviconBitmap(favicon_id,
1829          bitmaps_to_copy[j].bitmap_data, base::Time(),
1830          bitmaps_to_copy[j].pixel_size);
1831      favicon_sizes.push_back(bitmaps_to_copy[j].pixel_size);
1832
1833      if (favicon_sizes.size() >= kMaxFaviconBitmapsPerIconURL)
1834        break;
1835    }
1836  }
1837
1838  // Update the favicon mappings such that only |icon_url| is mapped to
1839  // |page_url|.
1840  bool mapping_changed = false;
1841  if (icon_mappings.size() != 1 || icon_mappings[0].icon_url != icon_url) {
1842    std::vector<favicon_base::FaviconID> favicon_ids;
1843    favicon_ids.push_back(favicon_id);
1844    SetFaviconMappingsForPageAndRedirects(page_url, icon_type, favicon_ids);
1845    mapping_changed = true;
1846  }
1847
1848  if (mapping_changed || !bitmap_identical)
1849    SendFaviconChangedNotificationForPageAndRedirects(page_url);
1850  ScheduleCommit();
1851}
1852
1853void HistoryBackend::SetFavicons(
1854    const GURL& page_url,
1855    favicon_base::IconType icon_type,
1856    const std::vector<favicon_base::FaviconRawBitmapData>&
1857        favicon_bitmap_data) {
1858  if (!thumbnail_db_ || !db_)
1859    return;
1860
1861  DCHECK(ValidateSetFaviconsParams(favicon_bitmap_data));
1862
1863  // Build map of FaviconRawBitmapData for each icon url.
1864  typedef std::map<GURL, std::vector<favicon_base::FaviconRawBitmapData> >
1865      BitmapDataByIconURL;
1866  BitmapDataByIconURL grouped_by_icon_url;
1867  for (size_t i = 0; i < favicon_bitmap_data.size(); ++i) {
1868    const GURL& icon_url = favicon_bitmap_data[i].icon_url;
1869    grouped_by_icon_url[icon_url].push_back(favicon_bitmap_data[i]);
1870  }
1871
1872  // Track whether the method modifies or creates any favicon bitmaps, favicons
1873  // or icon mappings.
1874  bool data_modified = false;
1875
1876  std::vector<favicon_base::FaviconID> icon_ids;
1877  for (BitmapDataByIconURL::const_iterator it = grouped_by_icon_url.begin();
1878       it != grouped_by_icon_url.end(); ++it) {
1879    const GURL& icon_url = it->first;
1880    favicon_base::FaviconID icon_id =
1881        thumbnail_db_->GetFaviconIDForFaviconURL(icon_url, icon_type, NULL);
1882
1883    if (!icon_id) {
1884      // TODO(pkotwicz): Remove the favicon sizes attribute from
1885      // ThumbnailDatabase::AddFavicon().
1886      icon_id = thumbnail_db_->AddFavicon(icon_url, icon_type);
1887      data_modified = true;
1888    }
1889    icon_ids.push_back(icon_id);
1890
1891    if (!data_modified)
1892      SetFaviconBitmaps(icon_id, it->second, &data_modified);
1893    else
1894      SetFaviconBitmaps(icon_id, it->second, NULL);
1895  }
1896
1897  data_modified |=
1898    SetFaviconMappingsForPageAndRedirects(page_url, icon_type, icon_ids);
1899
1900  if (data_modified) {
1901    // Send notification to the UI as an icon mapping, favicon, or favicon
1902    // bitmap was changed by this function.
1903    SendFaviconChangedNotificationForPageAndRedirects(page_url);
1904  }
1905  ScheduleCommit();
1906}
1907
1908void HistoryBackend::SetFaviconsOutOfDateForPage(const GURL& page_url) {
1909  std::vector<IconMapping> icon_mappings;
1910
1911  if (!thumbnail_db_ ||
1912      !thumbnail_db_->GetIconMappingsForPageURL(page_url,
1913                                                &icon_mappings))
1914    return;
1915
1916  for (std::vector<IconMapping>::iterator m = icon_mappings.begin();
1917       m != icon_mappings.end(); ++m) {
1918    thumbnail_db_->SetFaviconOutOfDate(m->icon_id);
1919  }
1920  ScheduleCommit();
1921}
1922
1923void HistoryBackend::CloneFavicons(const GURL& old_page_url,
1924                                   const GURL& new_page_url) {
1925  if (!thumbnail_db_)
1926    return;
1927
1928  // Prevent cross-domain cloning.
1929  if (old_page_url.GetOrigin() != new_page_url.GetOrigin())
1930    return;
1931
1932  thumbnail_db_->CloneIconMappings(old_page_url, new_page_url);
1933  ScheduleCommit();
1934}
1935
1936void HistoryBackend::SetImportedFavicons(
1937    const std::vector<ImportedFaviconUsage>& favicon_usage) {
1938  if (!db_ || !thumbnail_db_)
1939    return;
1940
1941  Time now = Time::Now();
1942
1943  // Track all URLs that had their favicons set or updated.
1944  std::set<GURL> favicons_changed;
1945
1946  for (size_t i = 0; i < favicon_usage.size(); i++) {
1947    favicon_base::FaviconID favicon_id =
1948        thumbnail_db_->GetFaviconIDForFaviconURL(
1949            favicon_usage[i].favicon_url, favicon_base::FAVICON, NULL);
1950    if (!favicon_id) {
1951      // This favicon doesn't exist yet, so we create it using the given data.
1952      // TODO(pkotwicz): Pass in real pixel size.
1953      favicon_id = thumbnail_db_->AddFavicon(
1954          favicon_usage[i].favicon_url,
1955          favicon_base::FAVICON,
1956          new base::RefCountedBytes(favicon_usage[i].png_data),
1957          now,
1958          gfx::Size());
1959    }
1960
1961    // Save the mapping from all the URLs to the favicon.
1962    HistoryClient* history_client = GetHistoryClient();
1963    for (std::set<GURL>::const_iterator url = favicon_usage[i].urls.begin();
1964         url != favicon_usage[i].urls.end(); ++url) {
1965      URLRow url_row;
1966      if (!db_->GetRowForURL(*url, &url_row)) {
1967        // If the URL is present as a bookmark, add the url in history to
1968        // save the favicon mapping. This will match with what history db does
1969        // for regular bookmarked URLs with favicons - when history db is
1970        // cleaned, we keep an entry in the db with 0 visits as long as that
1971        // url is bookmarked.
1972        if (history_client && history_client->IsBookmarked(*url)) {
1973          URLRow url_info(*url);
1974          url_info.set_visit_count(0);
1975          url_info.set_typed_count(0);
1976          url_info.set_last_visit(base::Time());
1977          url_info.set_hidden(false);
1978          db_->AddURL(url_info);
1979          thumbnail_db_->AddIconMapping(*url, favicon_id);
1980          favicons_changed.insert(*url);
1981        }
1982      } else {
1983        if (!thumbnail_db_->GetIconMappingsForPageURL(
1984                *url, favicon_base::FAVICON, NULL)) {
1985          // URL is present in history, update the favicon *only* if it is not
1986          // set already.
1987          thumbnail_db_->AddIconMapping(*url, favicon_id);
1988          favicons_changed.insert(*url);
1989        }
1990      }
1991    }
1992  }
1993
1994  if (!favicons_changed.empty()) {
1995    // Send the notification about the changed favicon URLs.
1996    scoped_ptr<FaviconChangedDetails> changed_details(
1997        new FaviconChangedDetails);
1998    changed_details->urls.swap(favicons_changed);
1999    BroadcastNotifications(chrome::NOTIFICATION_FAVICON_CHANGED,
2000                           changed_details.PassAs<HistoryDetails>());
2001  }
2002}
2003
2004void HistoryBackend::UpdateFaviconMappingsAndFetchImpl(
2005    const GURL* page_url,
2006    const std::vector<GURL>& icon_urls,
2007    int icon_types,
2008    int desired_size_in_dip,
2009    const std::vector<ui::ScaleFactor>& desired_scale_factors,
2010    std::vector<favicon_base::FaviconRawBitmapResult>* bitmap_results) {
2011  // If |page_url| is specified, |icon_types| must be either a single icon
2012  // type or icon types which are equivalent.
2013  DCHECK(!page_url || icon_types == favicon_base::FAVICON ||
2014         icon_types == favicon_base::TOUCH_ICON ||
2015         icon_types == favicon_base::TOUCH_PRECOMPOSED_ICON ||
2016         icon_types ==
2017             (favicon_base::TOUCH_ICON | favicon_base::TOUCH_PRECOMPOSED_ICON));
2018  bitmap_results->clear();
2019
2020  if (!thumbnail_db_) {
2021    return;
2022  }
2023
2024  std::vector<favicon_base::FaviconID> favicon_ids;
2025
2026  // The icon type for which the mappings will the updated and data will be
2027  // returned.
2028  favicon_base::IconType selected_icon_type = favicon_base::INVALID_ICON;
2029
2030  for (size_t i = 0; i < icon_urls.size(); ++i) {
2031    const GURL& icon_url = icon_urls[i];
2032    favicon_base::IconType icon_type_out;
2033    const favicon_base::FaviconID favicon_id =
2034        thumbnail_db_->GetFaviconIDForFaviconURL(
2035            icon_url, icon_types, &icon_type_out);
2036
2037    if (favicon_id) {
2038      // Return and update icon mappings only for the largest icon type. As
2039      // |icon_urls| is not sorted in terms of icon type, clear |favicon_ids|
2040      // if an |icon_url| with a larger icon type is found.
2041      if (icon_type_out > selected_icon_type) {
2042        selected_icon_type = icon_type_out;
2043        favicon_ids.clear();
2044      }
2045      if (icon_type_out == selected_icon_type)
2046        favicon_ids.push_back(favicon_id);
2047    }
2048  }
2049
2050  if (page_url && !favicon_ids.empty()) {
2051    bool mappings_updated =
2052        SetFaviconMappingsForPageAndRedirects(*page_url, selected_icon_type,
2053                                              favicon_ids);
2054    if (mappings_updated) {
2055      SendFaviconChangedNotificationForPageAndRedirects(*page_url);
2056      ScheduleCommit();
2057    }
2058  }
2059
2060  GetFaviconBitmapResultsForBestMatch(favicon_ids, desired_size_in_dip,
2061      desired_scale_factors, bitmap_results);
2062}
2063
2064void HistoryBackend::SetFaviconBitmaps(
2065    favicon_base::FaviconID icon_id,
2066    const std::vector<favicon_base::FaviconRawBitmapData>& favicon_bitmap_data,
2067    bool* favicon_bitmaps_changed) {
2068  if (favicon_bitmaps_changed)
2069    *favicon_bitmaps_changed = false;
2070
2071  std::vector<FaviconBitmapIDSize> bitmap_id_sizes;
2072  thumbnail_db_->GetFaviconBitmapIDSizes(icon_id, &bitmap_id_sizes);
2073
2074  std::vector<favicon_base::FaviconRawBitmapData> to_add = favicon_bitmap_data;
2075
2076  for (size_t i = 0; i < bitmap_id_sizes.size(); ++i) {
2077    const gfx::Size& pixel_size = bitmap_id_sizes[i].pixel_size;
2078    std::vector<favicon_base::FaviconRawBitmapData>::iterator match_it =
2079        to_add.end();
2080    for (std::vector<favicon_base::FaviconRawBitmapData>::iterator it =
2081             to_add.begin();
2082         it != to_add.end();
2083         ++it) {
2084      if (it->pixel_size == pixel_size) {
2085        match_it = it;
2086        break;
2087      }
2088    }
2089
2090    FaviconBitmapID bitmap_id = bitmap_id_sizes[i].bitmap_id;
2091    if (match_it == to_add.end()) {
2092      thumbnail_db_->DeleteFaviconBitmap(bitmap_id);
2093
2094      if (favicon_bitmaps_changed)
2095        *favicon_bitmaps_changed = true;
2096    } else {
2097      if (favicon_bitmaps_changed &&
2098          !*favicon_bitmaps_changed &&
2099          IsFaviconBitmapDataEqual(bitmap_id, match_it->bitmap_data)) {
2100        thumbnail_db_->SetFaviconBitmapLastUpdateTime(
2101            bitmap_id, base::Time::Now());
2102      } else {
2103        thumbnail_db_->SetFaviconBitmap(bitmap_id, match_it->bitmap_data,
2104            base::Time::Now());
2105
2106        if (favicon_bitmaps_changed)
2107          *favicon_bitmaps_changed = true;
2108      }
2109      to_add.erase(match_it);
2110    }
2111  }
2112
2113  for (size_t i = 0; i < to_add.size(); ++i) {
2114    thumbnail_db_->AddFaviconBitmap(icon_id, to_add[i].bitmap_data,
2115        base::Time::Now(), to_add[i].pixel_size);
2116
2117    if (favicon_bitmaps_changed)
2118      *favicon_bitmaps_changed = true;
2119  }
2120}
2121
2122bool HistoryBackend::ValidateSetFaviconsParams(const std::vector<
2123    favicon_base::FaviconRawBitmapData>& favicon_bitmap_data) const {
2124  typedef std::map<GURL, size_t> BitmapsPerIconURL;
2125  BitmapsPerIconURL num_bitmaps_per_icon_url;
2126  for (size_t i = 0; i < favicon_bitmap_data.size(); ++i) {
2127    if (!favicon_bitmap_data[i].bitmap_data.get())
2128      return false;
2129
2130    const GURL& icon_url = favicon_bitmap_data[i].icon_url;
2131    if (!num_bitmaps_per_icon_url.count(icon_url))
2132      num_bitmaps_per_icon_url[icon_url] = 1u;
2133    else
2134      ++num_bitmaps_per_icon_url[icon_url];
2135  }
2136
2137  if (num_bitmaps_per_icon_url.size() > kMaxFaviconsPerPage)
2138    return false;
2139
2140  for (BitmapsPerIconURL::const_iterator it = num_bitmaps_per_icon_url.begin();
2141       it != num_bitmaps_per_icon_url.end(); ++it) {
2142    if (it->second > kMaxFaviconBitmapsPerIconURL)
2143      return false;
2144  }
2145  return true;
2146}
2147
2148bool HistoryBackend::IsFaviconBitmapDataEqual(
2149    FaviconBitmapID bitmap_id,
2150    const scoped_refptr<base::RefCountedMemory>& new_bitmap_data) {
2151  if (!new_bitmap_data.get())
2152    return false;
2153
2154  scoped_refptr<base::RefCountedMemory> original_bitmap_data;
2155  thumbnail_db_->GetFaviconBitmap(bitmap_id,
2156                                  NULL,
2157                                  &original_bitmap_data,
2158                                  NULL);
2159  return new_bitmap_data->Equals(original_bitmap_data);
2160}
2161
2162bool HistoryBackend::GetFaviconsFromDB(
2163    const GURL& page_url,
2164    int icon_types,
2165    int desired_size_in_dip,
2166    const std::vector<ui::ScaleFactor>& desired_scale_factors,
2167    std::vector<favicon_base::FaviconRawBitmapResult>* favicon_bitmap_results) {
2168  DCHECK(favicon_bitmap_results);
2169  favicon_bitmap_results->clear();
2170
2171  if (!db_ || !thumbnail_db_)
2172    return false;
2173
2174  // Time the query.
2175  TimeTicks beginning_time = TimeTicks::Now();
2176
2177  // Get FaviconIDs for |page_url| and one of |icon_types|.
2178  std::vector<IconMapping> icon_mappings;
2179  thumbnail_db_->GetIconMappingsForPageURL(page_url, icon_types,
2180                                           &icon_mappings);
2181  std::vector<favicon_base::FaviconID> favicon_ids;
2182  for (size_t i = 0; i < icon_mappings.size(); ++i)
2183    favicon_ids.push_back(icon_mappings[i].icon_id);
2184
2185  // Populate |favicon_bitmap_results| and |icon_url_sizes|.
2186  bool success = GetFaviconBitmapResultsForBestMatch(favicon_ids,
2187      desired_size_in_dip, desired_scale_factors, favicon_bitmap_results);
2188  UMA_HISTOGRAM_TIMES("History.GetFavIconFromDB",  // historical name
2189                      TimeTicks::Now() - beginning_time);
2190  return success && !favicon_bitmap_results->empty();
2191}
2192
2193bool HistoryBackend::GetFaviconBitmapResultsForBestMatch(
2194    const std::vector<favicon_base::FaviconID>& candidate_favicon_ids,
2195    int desired_size_in_dip,
2196    const std::vector<ui::ScaleFactor>& desired_scale_factors,
2197    std::vector<favicon_base::FaviconRawBitmapResult>* favicon_bitmap_results) {
2198  favicon_bitmap_results->clear();
2199
2200  if (candidate_favicon_ids.empty())
2201    return true;
2202
2203  // Find the FaviconID and the FaviconBitmapIDs which best match
2204  // |desired_size_in_dip| and |desired_scale_factors|.
2205  // TODO(pkotwicz): Select bitmap results from multiple favicons once
2206  // content::FaviconStatus supports multiple icon URLs.
2207  favicon_base::FaviconID best_favicon_id = 0;
2208  std::vector<FaviconBitmapID> best_bitmap_ids;
2209  float highest_score = kSelectFaviconFramesInvalidScore;
2210  for (size_t i = 0; i < candidate_favicon_ids.size(); ++i) {
2211    std::vector<FaviconBitmapIDSize> bitmap_id_sizes;
2212    thumbnail_db_->GetFaviconBitmapIDSizes(candidate_favicon_ids[i],
2213                                           &bitmap_id_sizes);
2214
2215    // Build vector of gfx::Size from |bitmap_id_sizes|.
2216    std::vector<gfx::Size> sizes;
2217    for (size_t j = 0; j < bitmap_id_sizes.size(); ++j)
2218      sizes.push_back(bitmap_id_sizes[j].pixel_size);
2219
2220    std::vector<size_t> candidate_bitmap_indices;
2221    float score = 0;
2222    SelectFaviconFrameIndices(sizes,
2223                              desired_scale_factors,
2224                              desired_size_in_dip,
2225                              &candidate_bitmap_indices,
2226                              &score);
2227    if (score > highest_score) {
2228      highest_score = score;
2229      best_favicon_id = candidate_favicon_ids[i],
2230      best_bitmap_ids.clear();
2231      for (size_t j = 0; j < candidate_bitmap_indices.size(); ++j) {
2232        size_t candidate_index = candidate_bitmap_indices[j];
2233        best_bitmap_ids.push_back(
2234            bitmap_id_sizes[candidate_index].bitmap_id);
2235      }
2236    }
2237  }
2238
2239  // Construct FaviconRawBitmapResults from |best_favicon_id| and
2240  // |best_bitmap_ids|.
2241  GURL icon_url;
2242  favicon_base::IconType icon_type;
2243  if (!thumbnail_db_->GetFaviconHeader(best_favicon_id, &icon_url,
2244                                       &icon_type)) {
2245    return false;
2246  }
2247
2248  for (size_t i = 0; i < best_bitmap_ids.size(); ++i) {
2249    base::Time last_updated;
2250    favicon_base::FaviconRawBitmapResult bitmap_result;
2251    bitmap_result.icon_url = icon_url;
2252    bitmap_result.icon_type = icon_type;
2253    if (!thumbnail_db_->GetFaviconBitmap(best_bitmap_ids[i],
2254                                         &last_updated,
2255                                         &bitmap_result.bitmap_data,
2256                                         &bitmap_result.pixel_size)) {
2257      return false;
2258    }
2259
2260    bitmap_result.expired = (Time::Now() - last_updated) >
2261        TimeDelta::FromDays(kFaviconRefetchDays);
2262    if (bitmap_result.is_valid())
2263      favicon_bitmap_results->push_back(bitmap_result);
2264  }
2265  return true;
2266}
2267
2268bool HistoryBackend::SetFaviconMappingsForPageAndRedirects(
2269    const GURL& page_url,
2270    favicon_base::IconType icon_type,
2271    const std::vector<favicon_base::FaviconID>& icon_ids) {
2272  if (!thumbnail_db_)
2273    return false;
2274
2275  // Find all the pages whose favicons we should set, we want to set it for
2276  // all the pages in the redirect chain if it redirected.
2277  history::RedirectList redirects;
2278  GetCachedRecentRedirects(page_url, &redirects);
2279
2280  bool mappings_changed = false;
2281
2282  // Save page <-> favicon associations.
2283  for (history::RedirectList::const_iterator i(redirects.begin());
2284       i != redirects.end(); ++i) {
2285    mappings_changed |= SetFaviconMappingsForPage(*i, icon_type, icon_ids);
2286  }
2287  return mappings_changed;
2288}
2289
2290bool HistoryBackend::SetFaviconMappingsForPage(
2291    const GURL& page_url,
2292    favicon_base::IconType icon_type,
2293    const std::vector<favicon_base::FaviconID>& icon_ids) {
2294  DCHECK_LE(icon_ids.size(), kMaxFaviconsPerPage);
2295  bool mappings_changed = false;
2296
2297  // Two icon types are considered 'equivalent' if one of the icon types is
2298  // TOUCH_ICON and the other is TOUCH_PRECOMPOSED_ICON.
2299  //
2300  // Sets the icon mappings from |page_url| for |icon_type| to the favicons
2301  // with |icon_ids|. Mappings for |page_url| to favicons of type |icon_type|
2302  // whose FaviconID is not in |icon_ids| are removed. All icon mappings for
2303  // |page_url| to favicons of a type equivalent to |icon_type| are removed.
2304  // Remove any favicons which are orphaned as a result of the removal of the
2305  // icon mappings.
2306
2307  std::vector<favicon_base::FaviconID> unmapped_icon_ids = icon_ids;
2308
2309  std::vector<IconMapping> icon_mappings;
2310  thumbnail_db_->GetIconMappingsForPageURL(page_url, &icon_mappings);
2311
2312  for (std::vector<IconMapping>::iterator m = icon_mappings.begin();
2313       m != icon_mappings.end(); ++m) {
2314    std::vector<favicon_base::FaviconID>::iterator icon_id_it = std::find(
2315        unmapped_icon_ids.begin(), unmapped_icon_ids.end(), m->icon_id);
2316
2317    // If the icon mapping already exists, avoid removing it and adding it back.
2318    if (icon_id_it != unmapped_icon_ids.end()) {
2319      unmapped_icon_ids.erase(icon_id_it);
2320      continue;
2321    }
2322
2323    if ((icon_type == favicon_base::TOUCH_ICON &&
2324         m->icon_type == favicon_base::TOUCH_PRECOMPOSED_ICON) ||
2325        (icon_type == favicon_base::TOUCH_PRECOMPOSED_ICON &&
2326         m->icon_type == favicon_base::TOUCH_ICON) ||
2327        (icon_type == m->icon_type)) {
2328      thumbnail_db_->DeleteIconMapping(m->mapping_id);
2329
2330      // Removing the icon mapping may have orphaned the associated favicon so
2331      // we must recheck it. This is not super fast, but this case will get
2332      // triggered rarely, since normally a page will always map to the same
2333      // favicon IDs. It will mostly happen for favicons we import.
2334      if (!thumbnail_db_->HasMappingFor(m->icon_id))
2335        thumbnail_db_->DeleteFavicon(m->icon_id);
2336      mappings_changed = true;
2337    }
2338  }
2339
2340  for (size_t i = 0; i < unmapped_icon_ids.size(); ++i) {
2341    thumbnail_db_->AddIconMapping(page_url, unmapped_icon_ids[i]);
2342    mappings_changed = true;
2343  }
2344  return mappings_changed;
2345}
2346
2347void HistoryBackend::GetCachedRecentRedirects(
2348    const GURL& page_url,
2349    history::RedirectList* redirect_list) {
2350  RedirectCache::iterator iter = recent_redirects_.Get(page_url);
2351  if (iter != recent_redirects_.end()) {
2352    *redirect_list = iter->second;
2353
2354    // The redirect chain should have the destination URL as the last item.
2355    DCHECK(!redirect_list->empty());
2356    DCHECK(redirect_list->back() == page_url);
2357  } else {
2358    // No known redirects, construct mock redirect chain containing |page_url|.
2359    redirect_list->push_back(page_url);
2360  }
2361}
2362
2363void HistoryBackend::SendFaviconChangedNotificationForPageAndRedirects(
2364    const GURL& page_url) {
2365  history::RedirectList redirect_list;
2366  GetCachedRecentRedirects(page_url, &redirect_list);
2367
2368  scoped_ptr<FaviconChangedDetails> changed_details(new FaviconChangedDetails);
2369  for (size_t i = 0; i < redirect_list.size(); ++i)
2370    changed_details->urls.insert(redirect_list[i]);
2371
2372  BroadcastNotifications(chrome::NOTIFICATION_FAVICON_CHANGED,
2373                         changed_details.PassAs<HistoryDetails>());
2374}
2375
2376void HistoryBackend::Commit() {
2377  if (!db_)
2378    return;
2379
2380  // Note that a commit may not actually have been scheduled if a caller
2381  // explicitly calls this instead of using ScheduleCommit. Likewise, we
2382  // may reset the flag written by a pending commit. But this is OK! It
2383  // will merely cause extra commits (which is kind of the idea). We
2384  // could optimize more for this case (we may get two extra commits in
2385  // some cases) but it hasn't been important yet.
2386  CancelScheduledCommit();
2387
2388  db_->CommitTransaction();
2389  DCHECK(db_->transaction_nesting() == 0) << "Somebody left a transaction open";
2390  db_->BeginTransaction();
2391
2392  if (thumbnail_db_) {
2393    thumbnail_db_->CommitTransaction();
2394    DCHECK(thumbnail_db_->transaction_nesting() == 0) <<
2395        "Somebody left a transaction open";
2396    thumbnail_db_->BeginTransaction();
2397  }
2398}
2399
2400void HistoryBackend::ScheduleCommit() {
2401  if (scheduled_commit_.get())
2402    return;
2403  scheduled_commit_ = new CommitLaterTask(this);
2404  base::MessageLoop::current()->PostDelayedTask(
2405      FROM_HERE,
2406      base::Bind(&CommitLaterTask::RunCommit, scheduled_commit_.get()),
2407      base::TimeDelta::FromSeconds(kCommitIntervalSeconds));
2408}
2409
2410void HistoryBackend::CancelScheduledCommit() {
2411  if (scheduled_commit_.get()) {
2412    scheduled_commit_->Cancel();
2413    scheduled_commit_ = NULL;
2414  }
2415}
2416
2417void HistoryBackend::ProcessDBTaskImpl() {
2418  if (!db_) {
2419    // db went away, release all the refs.
2420    ReleaseDBTasks();
2421    return;
2422  }
2423
2424  // Remove any canceled tasks.
2425  while (!db_task_requests_.empty() && db_task_requests_.front()->canceled()) {
2426    db_task_requests_.front()->Release();
2427    db_task_requests_.pop_front();
2428  }
2429  if (db_task_requests_.empty())
2430    return;
2431
2432  // Run the first task.
2433  HistoryDBTaskRequest* request = db_task_requests_.front();
2434  db_task_requests_.pop_front();
2435  if (request->value->RunOnDBThread(this, db_.get())) {
2436    // The task is done. Notify the callback.
2437    request->ForwardResult();
2438    // We AddRef'd the request before adding, need to release it now.
2439    request->Release();
2440  } else {
2441    // Tasks wants to run some more. Schedule it at the end of current tasks.
2442    db_task_requests_.push_back(request);
2443    // And process it after an invoke later.
2444    base::MessageLoop::current()->PostTask(
2445        FROM_HERE, base::Bind(&HistoryBackend::ProcessDBTaskImpl, this));
2446  }
2447}
2448
2449void HistoryBackend::ReleaseDBTasks() {
2450  for (std::list<HistoryDBTaskRequest*>::iterator i =
2451       db_task_requests_.begin(); i != db_task_requests_.end(); ++i) {
2452    (*i)->Release();
2453  }
2454  db_task_requests_.clear();
2455}
2456
2457////////////////////////////////////////////////////////////////////////////////
2458//
2459// Generic operations
2460//
2461////////////////////////////////////////////////////////////////////////////////
2462
2463void HistoryBackend::DeleteURLs(const std::vector<GURL>& urls) {
2464  expirer_.DeleteURLs(urls);
2465
2466  db_->GetStartDate(&first_recorded_time_);
2467  // Force a commit, if the user is deleting something for privacy reasons, we
2468  // want to get it on disk ASAP.
2469  Commit();
2470}
2471
2472void HistoryBackend::DeleteURL(const GURL& url) {
2473  expirer_.DeleteURL(url);
2474
2475  db_->GetStartDate(&first_recorded_time_);
2476  // Force a commit, if the user is deleting something for privacy reasons, we
2477  // want to get it on disk ASAP.
2478  Commit();
2479}
2480
2481void HistoryBackend::ExpireHistoryBetween(
2482    const std::set<GURL>& restrict_urls,
2483    Time begin_time,
2484    Time end_time) {
2485  if (!db_)
2486    return;
2487
2488  if (begin_time.is_null() && (end_time.is_null() || end_time.is_max()) &&
2489      restrict_urls.empty()) {
2490    // Special case deleting all history so it can be faster and to reduce the
2491    // possibility of an information leak.
2492    DeleteAllHistory();
2493  } else {
2494    // Clearing parts of history, have the expirer do the depend
2495    expirer_.ExpireHistoryBetween(restrict_urls, begin_time, end_time);
2496
2497    // Force a commit, if the user is deleting something for privacy reasons,
2498    // we want to get it on disk ASAP.
2499    Commit();
2500  }
2501
2502  if (begin_time <= first_recorded_time_)
2503    db_->GetStartDate(&first_recorded_time_);
2504}
2505
2506void HistoryBackend::ExpireHistoryForTimes(
2507    const std::set<base::Time>& times,
2508    base::Time begin_time, base::Time end_time) {
2509  if (times.empty() || !db_)
2510    return;
2511
2512  DCHECK(*times.begin() >= begin_time)
2513      << "Min time is before begin time: "
2514      << times.begin()->ToJsTime() << " v.s. " << begin_time.ToJsTime();
2515  DCHECK(*times.rbegin() < end_time)
2516      << "Max time is after end time: "
2517      << times.rbegin()->ToJsTime() << " v.s. " << end_time.ToJsTime();
2518
2519  history::QueryOptions options;
2520  options.begin_time = begin_time;
2521  options.end_time = end_time;
2522  options.duplicate_policy = QueryOptions::KEEP_ALL_DUPLICATES;
2523  QueryResults results;
2524  QueryHistoryBasic(options, &results);
2525
2526  // 1st pass: find URLs that are visited at one of |times|.
2527  std::set<GURL> urls;
2528  for (size_t i = 0; i < results.size(); ++i) {
2529    if (times.count(results[i].visit_time()) > 0)
2530      urls.insert(results[i].url());
2531  }
2532  if (urls.empty())
2533    return;
2534
2535  // 2nd pass: collect all visit times of those URLs.
2536  std::vector<base::Time> times_to_expire;
2537  for (size_t i = 0; i < results.size(); ++i) {
2538    if (urls.count(results[i].url()))
2539      times_to_expire.push_back(results[i].visit_time());
2540  }
2541
2542  // Put the times in reverse chronological order and remove
2543  // duplicates (for expirer_.ExpireHistoryForTimes()).
2544  std::sort(times_to_expire.begin(), times_to_expire.end(),
2545            std::greater<base::Time>());
2546  times_to_expire.erase(
2547      std::unique(times_to_expire.begin(), times_to_expire.end()),
2548      times_to_expire.end());
2549
2550  // Expires by times and commit.
2551  DCHECK(!times_to_expire.empty());
2552  expirer_.ExpireHistoryForTimes(times_to_expire);
2553  Commit();
2554
2555  DCHECK(times_to_expire.back() >= first_recorded_time_);
2556  // Update |first_recorded_time_| if we expired it.
2557  if (times_to_expire.back() == first_recorded_time_)
2558    db_->GetStartDate(&first_recorded_time_);
2559}
2560
2561void HistoryBackend::ExpireHistory(
2562    const std::vector<history::ExpireHistoryArgs>& expire_list) {
2563  if (db_) {
2564    bool update_first_recorded_time = false;
2565
2566    for (std::vector<history::ExpireHistoryArgs>::const_iterator it =
2567         expire_list.begin(); it != expire_list.end(); ++it) {
2568      expirer_.ExpireHistoryBetween(it->urls, it->begin_time, it->end_time);
2569
2570      if (it->begin_time < first_recorded_time_)
2571        update_first_recorded_time = true;
2572    }
2573    Commit();
2574
2575    // Update |first_recorded_time_| if any deletion might have affected it.
2576    if (update_first_recorded_time)
2577      db_->GetStartDate(&first_recorded_time_);
2578  }
2579}
2580
2581void HistoryBackend::URLsNoLongerBookmarked(const std::set<GURL>& urls) {
2582  if (!db_)
2583    return;
2584
2585  for (std::set<GURL>::const_iterator i = urls.begin(); i != urls.end(); ++i) {
2586    URLRow url_row;
2587    if (!db_->GetRowForURL(*i, &url_row))
2588      continue;  // The URL isn't in the db; nothing to do.
2589
2590    VisitVector visits;
2591    db_->GetVisitsForURL(url_row.id(), &visits);
2592
2593    if (visits.empty())
2594      expirer_.DeleteURL(*i);  // There are no more visits; nuke the URL.
2595  }
2596}
2597
2598void HistoryBackend::DatabaseErrorCallback(int error, sql::Statement* stmt) {
2599  if (!scheduled_kill_db_ && sql::IsErrorCatastrophic(error)) {
2600    scheduled_kill_db_ = true;
2601    // Don't just do the close/delete here, as we are being called by |db| and
2602    // that seems dangerous.
2603    // TODO(shess): Consider changing KillHistoryDatabase() to use
2604    // RazeAndClose().  Then it can be cleared immediately.
2605    base::MessageLoop::current()->PostTask(
2606        FROM_HERE,
2607        base::Bind(&HistoryBackend::KillHistoryDatabase, this));
2608  }
2609}
2610
2611void HistoryBackend::KillHistoryDatabase() {
2612  scheduled_kill_db_ = false;
2613  if (!db_)
2614    return;
2615
2616  // Rollback transaction because Raze() cannot be called from within a
2617  // transaction.
2618  db_->RollbackTransaction();
2619  bool success = db_->Raze();
2620  UMA_HISTOGRAM_BOOLEAN("History.KillHistoryDatabaseResult", success);
2621
2622#if defined(OS_ANDROID)
2623  // Release AndroidProviderBackend before other objects.
2624  android_provider_backend_.reset();
2625#endif
2626
2627  // The expirer keeps tabs on the active databases. Tell it about the
2628  // databases which will be closed.
2629  expirer_.SetDatabases(NULL, NULL);
2630
2631  // Reopen a new transaction for |db_| for the sake of CloseAllDatabases().
2632  db_->BeginTransaction();
2633  CloseAllDatabases();
2634}
2635
2636void HistoryBackend::ProcessDBTask(
2637    scoped_refptr<HistoryDBTaskRequest> request) {
2638  DCHECK(request.get());
2639  if (request->canceled())
2640    return;
2641
2642  bool task_scheduled = !db_task_requests_.empty();
2643  // Make sure we up the refcount of the request. ProcessDBTaskImpl will
2644  // release when done with the task.
2645  request->AddRef();
2646  db_task_requests_.push_back(request.get());
2647  if (!task_scheduled) {
2648    // No other tasks are scheduled. Process request now.
2649    ProcessDBTaskImpl();
2650  }
2651}
2652
2653void HistoryBackend::BroadcastNotifications(
2654    int type,
2655    scoped_ptr<HistoryDetails> details) {
2656  // |delegate_| may be NULL if |this| is in the process of closing (closed by
2657  // HistoryService -> HistoryBackend::Closing().
2658  if (delegate_)
2659    delegate_->BroadcastNotifications(type, details.Pass());
2660}
2661
2662void HistoryBackend::NotifySyncURLsModified(URLRows* rows) {
2663  if (typed_url_syncable_service_.get())
2664    typed_url_syncable_service_->OnUrlsModified(rows);
2665}
2666
2667void HistoryBackend::NotifySyncURLsDeleted(bool all_history,
2668                                           bool expired,
2669                                           URLRows* rows) {
2670  if (typed_url_syncable_service_.get())
2671    typed_url_syncable_service_->OnUrlsDeleted(all_history, expired, rows);
2672}
2673
2674// Deleting --------------------------------------------------------------------
2675
2676void HistoryBackend::DeleteAllHistory() {
2677  // Our approach to deleting all history is:
2678  //  1. Copy the bookmarks and their dependencies to new tables with temporary
2679  //     names.
2680  //  2. Delete the original tables. Since tables can not share pages, we know
2681  //     that any data we don't want to keep is now in an unused page.
2682  //  3. Renaming the temporary tables to match the original.
2683  //  4. Vacuuming the database to delete the unused pages.
2684  //
2685  // Since we are likely to have very few bookmarks and their dependencies
2686  // compared to all history, this is also much faster than just deleting from
2687  // the original tables directly.
2688
2689  // Get the bookmarked URLs.
2690  std::vector<URLAndTitle> starred_urls;
2691  HistoryClient* history_client = GetHistoryClient();
2692  if (history_client)
2693    history_client->GetBookmarks(&starred_urls);
2694
2695  URLRows kept_urls;
2696  for (size_t i = 0; i < starred_urls.size(); i++) {
2697    URLRow row;
2698    if (!db_->GetRowForURL(starred_urls[i].url, &row))
2699      continue;
2700
2701    // Clear the last visit time so when we write these rows they are "clean."
2702    row.set_last_visit(Time());
2703    row.set_visit_count(0);
2704    row.set_typed_count(0);
2705    kept_urls.push_back(row);
2706  }
2707
2708  // Clear thumbnail and favicon history. The favicons for the given URLs will
2709  // be kept.
2710  if (!ClearAllThumbnailHistory(kept_urls)) {
2711    LOG(ERROR) << "Thumbnail history could not be cleared";
2712    // We continue in this error case. If the user wants to delete their
2713    // history, we should delete as much as we can.
2714  }
2715
2716  // ClearAllMainHistory will change the IDs of the URLs in kept_urls.
2717  // Therefore, we clear the list afterwards to make sure nobody uses this
2718  // invalid data.
2719  if (!ClearAllMainHistory(kept_urls))
2720    LOG(ERROR) << "Main history could not be cleared";
2721  kept_urls.clear();
2722
2723  db_->GetStartDate(&first_recorded_time_);
2724
2725  // Send out the notification that history is cleared. The in-memory database
2726  // will pick this up and clear itself.
2727  scoped_ptr<URLsDeletedDetails> details(new URLsDeletedDetails);
2728  details->all_history = true;
2729  NotifySyncURLsDeleted(true, false, NULL);
2730  BroadcastNotifications(chrome::NOTIFICATION_HISTORY_URLS_DELETED,
2731                         details.PassAs<HistoryDetails>());
2732}
2733
2734bool HistoryBackend::ClearAllThumbnailHistory(const URLRows& kept_urls) {
2735  if (!thumbnail_db_) {
2736    // When we have no reference to the thumbnail database, maybe there was an
2737    // error opening it. In this case, we just try to blow it away to try to
2738    // fix the error if it exists. This may fail, in which case either the
2739    // file doesn't exist or there's no more we can do.
2740    sql::Connection::Delete(GetFaviconsFileName());
2741
2742    // Older version of the database.
2743    sql::Connection::Delete(GetThumbnailFileName());
2744    return true;
2745  }
2746
2747  // Urls to retain mappings for.
2748  std::vector<GURL> urls_to_keep;
2749  for (URLRows::const_iterator i = kept_urls.begin();
2750       i != kept_urls.end(); ++i) {
2751    urls_to_keep.push_back(i->url());
2752  }
2753
2754  // Isolate from any long-running transaction.
2755  thumbnail_db_->CommitTransaction();
2756  thumbnail_db_->BeginTransaction();
2757
2758  // TODO(shess): If this fails, perhaps the database should be razed
2759  // or deleted.
2760  if (!thumbnail_db_->RetainDataForPageUrls(urls_to_keep)) {
2761    thumbnail_db_->RollbackTransaction();
2762    thumbnail_db_->BeginTransaction();
2763    return false;
2764  }
2765
2766#if defined(OS_ANDROID)
2767  // TODO (michaelbai): Add the unit test once AndroidProviderBackend is
2768  // avaliable in HistoryBackend.
2769  db_->ClearAndroidURLRows();
2770#endif
2771
2772  // Vacuum to remove all the pages associated with the dropped tables. There
2773  // must be no transaction open on the table when we do this. We assume that
2774  // our long-running transaction is open, so we complete it and start it again.
2775  DCHECK(thumbnail_db_->transaction_nesting() == 1);
2776  thumbnail_db_->CommitTransaction();
2777  thumbnail_db_->Vacuum();
2778  thumbnail_db_->BeginTransaction();
2779  return true;
2780}
2781
2782bool HistoryBackend::ClearAllMainHistory(const URLRows& kept_urls) {
2783  // Create the duplicate URL table. We will copy the kept URLs into this.
2784  if (!db_->CreateTemporaryURLTable())
2785    return false;
2786
2787  // Insert the URLs into the temporary table.
2788  for (URLRows::const_iterator i = kept_urls.begin(); i != kept_urls.end();
2789       ++i) {
2790    db_->AddTemporaryURL(*i);
2791  }
2792
2793  // Replace the original URL table with the temporary one.
2794  if (!db_->CommitTemporaryURLTable())
2795    return false;
2796
2797  // Delete the old tables and recreate them empty.
2798  db_->RecreateAllTablesButURL();
2799
2800  // Vacuum to reclaim the space from the dropped tables. This must be done
2801  // when there is no transaction open, and we assume that our long-running
2802  // transaction is currently open.
2803  db_->CommitTransaction();
2804  db_->Vacuum();
2805  db_->BeginTransaction();
2806  db_->GetStartDate(&first_recorded_time_);
2807
2808  return true;
2809}
2810
2811HistoryClient* HistoryBackend::GetHistoryClient() {
2812  if (history_client_)
2813    history_client_->BlockUntilBookmarksLoaded();
2814  return history_client_;
2815}
2816
2817void HistoryBackend::NotifyVisitObservers(const VisitRow& visit) {
2818  BriefVisitInfo info;
2819  info.url_id = visit.url_id;
2820  info.time = visit.visit_time;
2821  info.transition = visit.transition;
2822  // If we don't have a delegate yet during setup or shutdown, we will drop
2823  // these notifications.
2824  if (delegate_)
2825    delegate_->NotifyVisitDBObserversOnAddVisit(info);
2826}
2827
2828#if defined(OS_ANDROID)
2829void HistoryBackend::PopulateMostVisitedURLMap() {
2830  MostVisitedURLList most_visited_urls;
2831  QueryMostVisitedURLsImpl(kPageVisitStatsMaxTopSites, kSegmentDataRetention,
2832                           &most_visited_urls);
2833
2834  DCHECK_LE(most_visited_urls.size(), kPageVisitStatsMaxTopSites);
2835  for (size_t i = 0; i < most_visited_urls.size(); ++i) {
2836    most_visited_urls_map_[most_visited_urls[i].url] = i;
2837    for (size_t j = 0; j < most_visited_urls[i].redirects.size(); ++j)
2838      most_visited_urls_map_[most_visited_urls[i].redirects[j]] = i;
2839  }
2840}
2841
2842void HistoryBackend::RecordTopPageVisitStats(const GURL& url) {
2843  int rank = kPageVisitStatsMaxTopSites;
2844  std::map<GURL, int>::const_iterator it = most_visited_urls_map_.find(url);
2845  if (it != most_visited_urls_map_.end())
2846    rank = (*it).second;
2847  UMA_HISTOGRAM_ENUMERATION("History.TopSitesVisitsByRank",
2848                            rank, kPageVisitStatsMaxTopSites + 1);
2849}
2850#endif
2851
2852}  // namespace history
2853