root/chrome/browser/history/history_service.cc

DEFINITIONS

1. RunWithFaviconResults
2. RunWithFaviconResult
3. end_
4. NextURL
5. HasNextURL
6. ExpireWebHistoryComplete
7. profile_
8. NotifyProfileError
9. SetInMemoryBackend
10. BroadcastNotifications
11. DBLoaded
12. NotifyVisitDBObserversOnAddVisit
13. no_db_
14. no_db_
15. BackendLoaded
16. Cleanup
17. NotifyRenderProcessHostDestruction
18. InMemoryDatabase
19. GetTypedCountForURL
20. GetLastVisitTimeForURL
21. GetVisitCountForURL
22. GetTypedUrlSyncableService
23. Shutdown
24. SetKeywordSearchTermsForURL
25. DeleteAllSearchTermsForKeyword
26. GetMostRecentKeywordSearchTerms
27. DeleteKeywordSearchTermForURL
28. DeleteMatchingURLsForKeyword
29. URLsNoLongerBookmarked
30. ScheduleDBTask
31. QuerySegmentUsageSince
32. FlushForTest
33. SetOnBackendDestroyTask
34. AddPage
35. AddPage
36. AddPage
37. AddPageNoVisitForBookmark
38. SetPageTitle
39. UpdateWithPageEndTime
40. AddPageWithDetails
41. AddPagesWithDetails
42. GetFavicons
43. GetFaviconsForURL
44. GetLargestFaviconForURL
45. GetFaviconForID
46. UpdateFaviconMappingsAndFetch
47. MergeFavicon
48. SetFavicons
49. SetFaviconsOutOfDateForPage
50. CloneFavicons
51. SetImportedFavicons
52. QueryURL
53. CreateDownload
54. GetNextDownloadId
55. QueryDownloads
56. UpdateDownload
57. RemoveDownloads
58. QueryHistory
59. QueryRedirectsFrom
60. QueryRedirectsTo
61. GetVisibleVisitCountToHost
62. QueryTopURLsAndRedirects
63. QueryMostVisitedURLs
64. QueryFilteredURLs
65. Observe
66. RebuildTable
67. Init
68. ScheduleAutocomplete
69. ScheduleTask
70. CanAddURL
71. AsWeakPtr
72. MergeDataAndStartSyncing
73. StopSyncing
74. GetAllSyncData
75. ProcessSyncChanges
76. ProcessLocalDeleteDirective
77. SetInMemoryBackend
78. NotifyProfileError
79. DeleteURL
80. DeleteURLsForTest
81. ExpireHistoryBetween
82. ExpireHistory
83. ExpireLocalAndRemoteHistoryBetween
84. BroadcastNotificationsHelper
85. OnDBLoaded
86. GetRowForURL
87. AddVisitDatabaseObserver
88. RemoveVisitDatabaseObserver
89. NotifyVisitDBObserversOnAddVisit

// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// The history system runs on a background thread so that potentially slow
// database operations don't delay the browser. This backend processing is
// represented by HistoryBackend. The HistoryService's job is to dispatch to
// that thread.
//
// Main thread                       History thread
// -----------                       --------------
// HistoryService <----------------> HistoryBackend
//                                   -> HistoryDatabase
//                                      -> SQLite connection to History
//                                   -> ArchivedDatabase
//                                      -> SQLite connection to Archived History
//                                   -> ThumbnailDatabase
//                                      -> SQLite connection to Thumbnails
//                                         (and favicons)

#include "chrome/browser/history/history_service.h"

#include "base/bind_helpers.h"
#include "base/callback.h"
#include "base/command_line.h"
#include "base/compiler_specific.h"
#include "base/location.h"
#include "base/memory/ref_counted.h"
#include "base/message_loop/message_loop.h"
#include "base/path_service.h"
#include "base/prefs/pref_service.h"
#include "base/thread_task_runner_handle.h"
#include "base/threading/thread.h"
#include "base/time/time.h"
#include "chrome/browser/autocomplete/history_url_provider.h"
#include "chrome/browser/bookmarks/bookmark_model.h"
#include "chrome/browser/bookmarks/bookmark_model_factory.h"
#include "chrome/browser/browser_process.h"
#include "chrome/browser/chrome_notification_types.h"
#include "chrome/browser/history/download_row.h"
#include "chrome/browser/history/history_backend.h"
#include "chrome/browser/history/history_notifications.h"
#include "chrome/browser/history/history_types.h"
#include "chrome/browser/history/in_memory_database.h"
#include "chrome/browser/history/in_memory_history_backend.h"
#include "chrome/browser/history/in_memory_url_index.h"
#include "chrome/browser/history/top_sites.h"
#include "chrome/browser/history/visit_database.h"
#include "chrome/browser/history/visit_filter.h"
#include "chrome/browser/history/web_history_service.h"
#include "chrome/browser/history/web_history_service_factory.h"
#include "chrome/browser/profiles/profile.h"
#include "chrome/browser/ui/profile_error_dialog.h"
#include "chrome/common/chrome_constants.h"
#include "chrome/common/chrome_switches.h"
#include "chrome/common/importer/imported_favicon_usage.h"
#include "chrome/common/pref_names.h"
#include "chrome/common/thumbnail_score.h"
#include "chrome/common/url_constants.h"
#include "components/visitedlink/browser/visitedlink_master.h"
#include "content/public/browser/browser_thread.h"
#include "content/public/browser/download_item.h"
#include "content/public/browser/notification_service.h"
#include "grit/chromium_strings.h"
#include "grit/generated_resources.h"
#include "sync/api/sync_error_factory.h"
#include "third_party/skia/include/core/SkBitmap.h"

using base::Time;
using history::HistoryBackend;

namespace {

static const char* kHistoryThreadName = "Chrome_HistoryThread";

void RunWithFaviconResults(
    const FaviconService::FaviconResultsCallback& callback,
    std::vector<chrome::FaviconBitmapResult>* bitmap_results) {
  callback.Run(*bitmap_results);
}

void RunWithFaviconResult(
    const FaviconService::FaviconRawCallback& callback,
    chrome::FaviconBitmapResult* bitmap_result) {
  callback.Run(*bitmap_result);
}

// Extract history::URLRows into GURLs for VisitedLinkMaster.
class URLIteratorFromURLRows
    : public visitedlink::VisitedLinkMaster::URLIterator {
 public:
  explicit URLIteratorFromURLRows(const history::URLRows& url_rows)
      : itr_(url_rows.begin()),
        end_(url_rows.end()) {
  }

  virtual const GURL& NextURL() OVERRIDE {
    return (itr_++)->url();
  }

  virtual bool HasNextURL() const OVERRIDE {
    return itr_ != end_;
  }

 private:
  history::URLRows::const_iterator itr_;
  history::URLRows::const_iterator end_;

  DISALLOW_COPY_AND_ASSIGN(URLIteratorFromURLRows);
};

// Callback from WebHistoryService::ExpireWebHistory().
void ExpireWebHistoryComplete(bool success) {
  // Ignore the result.
  //
  // TODO(davidben): ExpireLocalAndRemoteHistoryBetween callback should not fire
  // until this completes.
}

}  // namespace

// Sends messages from the backend to us on the main thread. This must be a
// separate class from the history service so that it can hold a reference to
// the history service (otherwise we would have to manually AddRef and
// Release when the Backend has a reference to us).
class HistoryService::BackendDelegate : public HistoryBackend::Delegate {
 public:
  BackendDelegate(
      const base::WeakPtr<HistoryService>& history_service,
      const scoped_refptr<base::SequencedTaskRunner>& service_task_runner,
      Profile* profile)
      : history_service_(history_service),
        service_task_runner_(service_task_runner),
        profile_(profile) {
  }

  virtual void NotifyProfileError(sql::InitStatus init_status) OVERRIDE {
    // Send to the history service on the main thread.
    service_task_runner_->PostTask(
        FROM_HERE,
        base::Bind(&HistoryService::NotifyProfileError, history_service_,
                   init_status));
  }

  virtual void SetInMemoryBackend(
      scoped_ptr<history::InMemoryHistoryBackend> backend) OVERRIDE {
    // Send the backend to the history service on the main thread.
    service_task_runner_->PostTask(
        FROM_HERE,
        base::Bind(&HistoryService::SetInMemoryBackend, history_service_,
                   base::Passed(&backend)));
  }

  virtual void BroadcastNotifications(
      int type,
      scoped_ptr<history::HistoryDetails> details) OVERRIDE {
    // Send the notification on the history thread.
    if (content::NotificationService::current()) {
      content::Details<history::HistoryDetails> det(details.get());
      content::NotificationService::current()->Notify(
          type, content::Source<Profile>(profile_), det);
    }
    // Send the notification to the history service on the main thread.
    service_task_runner_->PostTask(
        FROM_HERE,
        base::Bind(&HistoryService::BroadcastNotificationsHelper,
                   history_service_, type, base::Passed(&details)));
  }

  virtual void DBLoaded() OVERRIDE {
    service_task_runner_->PostTask(
        FROM_HERE,
        base::Bind(&HistoryService::OnDBLoaded, history_service_));
  }

  virtual void NotifyVisitDBObserversOnAddVisit(
      const history::BriefVisitInfo& info) OVERRIDE {
    service_task_runner_->PostTask(
        FROM_HERE,
        base::Bind(&HistoryService::NotifyVisitDBObserversOnAddVisit,
                   history_service_, info));
  }

 private:
  const base::WeakPtr<HistoryService> history_service_;
  const scoped_refptr<base::SequencedTaskRunner> service_task_runner_;
  Profile* const profile_;
};

// The history thread is intentionally not a BrowserThread because the
// sync integration unit tests depend on being able to create more than one
// history thread.
HistoryService::HistoryService()
    : weak_ptr_factory_(this),
      thread_(new base::Thread(kHistoryThreadName)),
      profile_(NULL),
      backend_loaded_(false),
      bookmark_service_(NULL),
      no_db_(false) {
}

HistoryService::HistoryService(Profile* profile)
    : weak_ptr_factory_(this),
      thread_(new base::Thread(kHistoryThreadName)),
      profile_(profile),
      visitedlink_master_(new visitedlink::VisitedLinkMaster(
          profile, this, true)),
      backend_loaded_(false),
      bookmark_service_(NULL),
      no_db_(false) {
  DCHECK(profile_);
  registrar_.Add(this, chrome::NOTIFICATION_HISTORY_URLS_DELETED,
                 content::Source<Profile>(profile_));
  registrar_.Add(this, chrome::NOTIFICATION_TEMPLATE_URL_REMOVED,
                 content::Source<Profile>(profile_));
}

HistoryService::~HistoryService() {
  DCHECK(thread_checker_.CalledOnValidThread());
  // Shutdown the backend. This does nothing if Cleanup was already invoked.
  Cleanup();
}

bool HistoryService::BackendLoaded() {
  DCHECK(thread_checker_.CalledOnValidThread());
  return backend_loaded_;
}

void HistoryService::Cleanup() {
  DCHECK(thread_checker_.CalledOnValidThread());
  if (!thread_) {
    // We've already cleaned up.
    return;
  }

  weak_ptr_factory_.InvalidateWeakPtrs();

  // Unload the backend.
  if (history_backend_) {
    // Get rid of the in-memory backend.
    in_memory_backend_.reset();

    // Give the InMemoryURLIndex a chance to shutdown.
    // NOTE: In tests, there may be no index.
    if (in_memory_url_index_)
      in_memory_url_index_->ShutDown();

    // The backend's destructor must run on the history thread since it is not
    // threadsafe. So this thread must not be the last thread holding a
    // reference to the backend, or a crash could happen.
    //
    // We have a reference to the history backend. There is also an extra
    // reference held by our delegate installed in the backend, which
    // HistoryBackend::Closing will release. This means if we scheduled a call
    // to HistoryBackend::Closing and *then* released our backend reference,
    // there will be a race between us and the backend's Closing function to see
    // who is the last holder of a reference. If the backend thread's Closing
    // manages to run before we release our backend refptr, the last reference
    // will be held by this thread and the destructor will be called from here.
    //
    // Therefore, we create a closure to run the Closing operation first. This
    // holds a reference to the backend. Then we release our reference, then we
    // schedule the task to run. After the task runs, it will delete its
    // reference from the history thread, ensuring everything works properly.
    //
    // TODO(ajwong): Cleanup HistoryBackend lifetime issues.
    //     See http://crbug.com/99767.
    history_backend_->AddRef();
    base::Closure closing_task =
        base::Bind(&HistoryBackend::Closing, history_backend_.get());
    ScheduleTask(PRIORITY_NORMAL, closing_task);
    closing_task.Reset();
    HistoryBackend* raw_ptr = history_backend_.get();
    history_backend_ = NULL;
    thread_->message_loop()->ReleaseSoon(FROM_HERE, raw_ptr);
  }

  // Delete the thread, which joins with the background thread. We defensively
  // NULL the pointer before deleting it in case somebody tries to use it
  // during shutdown, but this shouldn't happen.
  base::Thread* thread = thread_;
  thread_ = NULL;
  delete thread;
}

void HistoryService::NotifyRenderProcessHostDestruction(const void* host) {
  DCHECK(thread_checker_.CalledOnValidThread());
  ScheduleAndForget(PRIORITY_NORMAL,
                    &HistoryBackend::NotifyRenderProcessHostDestruction, host);
}

history::URLDatabase* HistoryService::InMemoryDatabase() {
  DCHECK(thread_checker_.CalledOnValidThread());
  return in_memory_backend_ ? in_memory_backend_->db() : NULL;
}

bool HistoryService::GetTypedCountForURL(const GURL& url, int* typed_count) {
  DCHECK(thread_checker_.CalledOnValidThread());
  history::URLRow url_row;
  if (!GetRowForURL(url, &url_row))
    return false;
  *typed_count = url_row.typed_count();
  return true;
}

bool HistoryService::GetLastVisitTimeForURL(const GURL& url,
                                            base::Time* last_visit) {
  DCHECK(thread_checker_.CalledOnValidThread());
  history::URLRow url_row;
  if (!GetRowForURL(url, &url_row))
    return false;
  *last_visit = url_row.last_visit();
  return true;
}

bool HistoryService::GetVisitCountForURL(const GURL& url, int* visit_count) {
  DCHECK(thread_checker_.CalledOnValidThread());
  history::URLRow url_row;
  if (!GetRowForURL(url, &url_row))
    return false;
  *visit_count = url_row.visit_count();
  return true;
}

history::TypedUrlSyncableService* HistoryService::GetTypedUrlSyncableService()
    const {
  return history_backend_->GetTypedUrlSyncableService();
}

void HistoryService::Shutdown() {
  DCHECK(thread_checker_.CalledOnValidThread());
  // It's possible that bookmarks haven't loaded and history is waiting for
  // bookmarks to complete loading. In such a situation history can't shutdown
  // (meaning if we invoked history_service_->Cleanup now, we would
  // deadlock). To break the deadlock we tell BookmarkModel it's about to be
  // deleted so that it can release the signal history is waiting on, allowing
  // history to shutdown (history_service_->Cleanup to complete). In such a
  // scenario history sees an incorrect view of bookmarks, but it's better
  // than a deadlock.
  BookmarkModel* bookmark_model = static_cast<BookmarkModel*>(
      BookmarkModelFactory::GetForProfileIfExists(profile_));
  if (bookmark_model)
    bookmark_model->Shutdown();

  Cleanup();
}

void HistoryService::SetKeywordSearchTermsForURL(const GURL& url,
                                                 TemplateURLID keyword_id,
                                                 const base::string16& term) {
  DCHECK(thread_checker_.CalledOnValidThread());
  ScheduleAndForget(PRIORITY_UI,
                    &HistoryBackend::SetKeywordSearchTermsForURL,
                    url, keyword_id, term);
}

void HistoryService::DeleteAllSearchTermsForKeyword(
    TemplateURLID keyword_id) {
  DCHECK(thread_checker_.CalledOnValidThread());
  ScheduleAndForget(PRIORITY_UI,
                    &HistoryBackend::DeleteAllSearchTermsForKeyword,
                    keyword_id);
}

HistoryService::Handle HistoryService::GetMostRecentKeywordSearchTerms(
    TemplateURLID keyword_id,
    const base::string16& prefix,
    int max_count,
    CancelableRequestConsumerBase* consumer,
    const GetMostRecentKeywordSearchTermsCallback& callback) {
  DCHECK(thread_checker_.CalledOnValidThread());
  return Schedule(PRIORITY_UI, &HistoryBackend::GetMostRecentKeywordSearchTerms,
                  consumer,
                  new history::GetMostRecentKeywordSearchTermsRequest(callback),
                  keyword_id, prefix, max_count);
}

void HistoryService::DeleteKeywordSearchTermForURL(const GURL& url) {
  DCHECK(thread_checker_.CalledOnValidThread());
  ScheduleAndForget(PRIORITY_UI, &HistoryBackend::DeleteKeywordSearchTermForURL,
                    url);
}

void HistoryService::DeleteMatchingURLsForKeyword(TemplateURLID keyword_id,
                                                  const base::string16& term) {
  DCHECK(thread_checker_.CalledOnValidThread());
  ScheduleAndForget(PRIORITY_UI, &HistoryBackend::DeleteMatchingURLsForKeyword,
                    keyword_id, term);
}

void HistoryService::URLsNoLongerBookmarked(const std::set<GURL>& urls) {
  DCHECK(thread_checker_.CalledOnValidThread());
  ScheduleAndForget(PRIORITY_NORMAL, &HistoryBackend::URLsNoLongerBookmarked,
                    urls);
}

void HistoryService::ScheduleDBTask(history::HistoryDBTask* task,
                                    CancelableRequestConsumerBase* consumer) {
  DCHECK(thread_checker_.CalledOnValidThread());
  history::HistoryDBTaskRequest* request = new history::HistoryDBTaskRequest(
      base::Bind(&history::HistoryDBTask::DoneRunOnMainThread, task));
  request->value = task;  // The value is the task to execute.
  Schedule(PRIORITY_UI, &HistoryBackend::ProcessDBTask, consumer, request);
}

HistoryService::Handle HistoryService::QuerySegmentUsageSince(
    CancelableRequestConsumerBase* consumer,
    const Time from_time,
    int max_result_count,
    const SegmentQueryCallback& callback) {
  DCHECK(thread_checker_.CalledOnValidThread());
  return Schedule(PRIORITY_UI, &HistoryBackend::QuerySegmentUsage,
                  consumer, new history::QuerySegmentUsageRequest(callback),
                  from_time, max_result_count);
}

void HistoryService::FlushForTest(const base::Closure& flushed) {
  thread_->message_loop_proxy()->PostTaskAndReply(
      FROM_HERE, base::Bind(&base::DoNothing), flushed);
}

void HistoryService::SetOnBackendDestroyTask(const base::Closure& task) {
  DCHECK(thread_checker_.CalledOnValidThread());
  ScheduleAndForget(PRIORITY_NORMAL, &HistoryBackend::SetOnBackendDestroyTask,
                    base::MessageLoop::current(), task);
}

void HistoryService::AddPage(const GURL& url,
                             Time time,
                             const void* id_scope,
                             int32 page_id,
                             const GURL& referrer,
                             const history::RedirectList& redirects,
                             content::PageTransition transition,
                             history::VisitSource visit_source,
                             bool did_replace_entry) {
  DCHECK(thread_checker_.CalledOnValidThread());
  AddPage(
      history::HistoryAddPageArgs(url, time, id_scope, page_id, referrer,
                                  redirects, transition, visit_source,
                                  did_replace_entry));
}

void HistoryService::AddPage(const GURL& url,
                             base::Time time,
                             history::VisitSource visit_source) {
  DCHECK(thread_checker_.CalledOnValidThread());
  AddPage(
      history::HistoryAddPageArgs(url, time, NULL, 0, GURL(),
                                  history::RedirectList(),
                                  content::PAGE_TRANSITION_LINK,
                                  visit_source, false));
}

void HistoryService::AddPage(const history::HistoryAddPageArgs& add_page_args) {
  DCHECK(thread_checker_.CalledOnValidThread());
  DCHECK(thread_) << "History service being called after cleanup";

  // Filter out unwanted URLs. We don't add auto-subframe URLs. They are a
  // large part of history (think iframes for ads) and we never display them in
  // history UI. We will still add manual subframes, which are ones the user
  // has clicked on to get.
  if (!CanAddURL(add_page_args.url))
    return;

  // Add link & all redirects to visited link list.
  if (visitedlink_master_) {
    visitedlink_master_->AddURL(add_page_args.url);

    if (!add_page_args.redirects.empty()) {
      // We should not be asked to add a page in the middle of a redirect chain.
      DCHECK_EQ(add_page_args.url,
                add_page_args.redirects[add_page_args.redirects.size() - 1]);

      // We need the !redirects.empty() condition above since size_t is unsigned
      // and will wrap around when we subtract one from a 0 size.
      for (size_t i = 0; i < add_page_args.redirects.size() - 1; i++)
        visitedlink_master_->AddURL(add_page_args.redirects[i]);
    }
  }

  ScheduleAndForget(PRIORITY_NORMAL, &HistoryBackend::AddPage, add_page_args);
}

void HistoryService::AddPageNoVisitForBookmark(const GURL& url,
                                               const base::string16& title) {
  DCHECK(thread_checker_.CalledOnValidThread());
  if (!CanAddURL(url))
    return;

  ScheduleAndForget(PRIORITY_NORMAL,
                    &HistoryBackend::AddPageNoVisitForBookmark, url, title);
}

void HistoryService::SetPageTitle(const GURL& url,
                                  const base::string16& title) {
  DCHECK(thread_checker_.CalledOnValidThread());
  ScheduleAndForget(PRIORITY_NORMAL, &HistoryBackend::SetPageTitle, url, title);
}

void HistoryService::UpdateWithPageEndTime(const void* host,
                                           int32 page_id,
                                           const GURL& url,
                                           Time end_ts) {
  DCHECK(thread_checker_.CalledOnValidThread());
  ScheduleAndForget(PRIORITY_NORMAL, &HistoryBackend::UpdateWithPageEndTime,
                    host, page_id, url, end_ts);
}

void HistoryService::AddPageWithDetails(const GURL& url,
                                        const base::string16& title,
                                        int visit_count,
                                        int typed_count,
                                        Time last_visit,
                                        bool hidden,
                                        history::VisitSource visit_source) {
  DCHECK(thread_checker_.CalledOnValidThread());
  // Filter out unwanted URLs.
  if (!CanAddURL(url))
    return;

  // Add to the visited links system.
  if (visitedlink_master_)
    visitedlink_master_->AddURL(url);

  history::URLRow row(url);
  row.set_title(title);
  row.set_visit_count(visit_count);
  row.set_typed_count(typed_count);
  row.set_last_visit(last_visit);
  row.set_hidden(hidden);

  history::URLRows rows;
  rows.push_back(row);

  ScheduleAndForget(PRIORITY_NORMAL,
                    &HistoryBackend::AddPagesWithDetails, rows, visit_source);
}

void HistoryService::AddPagesWithDetails(const history::URLRows& info,
                                         history::VisitSource visit_source) {
  DCHECK(thread_checker_.CalledOnValidThread());
  // Add to the visited links system.
  if (visitedlink_master_) {
    std::vector<GURL> urls;
    urls.reserve(info.size());
    for (history::URLRows::const_iterator i = info.begin(); i != info.end();
         ++i)
      urls.push_back(i->url());

    visitedlink_master_->AddURLs(urls);
  }

  ScheduleAndForget(PRIORITY_NORMAL,
                    &HistoryBackend::AddPagesWithDetails, info, visit_source);
}

base::CancelableTaskTracker::TaskId HistoryService::GetFavicons(
    const std::vector<GURL>& icon_urls,
    int icon_types,
    int desired_size_in_dip,
    const std::vector<ui::ScaleFactor>& desired_scale_factors,
    const FaviconService::FaviconResultsCallback& callback,
    base::CancelableTaskTracker* tracker) {
  DCHECK(thread_checker_.CalledOnValidThread());

  std::vector<chrome::FaviconBitmapResult>* results =
      new std::vector<chrome::FaviconBitmapResult>();
  return tracker->PostTaskAndReply(
      thread_->message_loop_proxy().get(),
      FROM_HERE,
      base::Bind(&HistoryBackend::GetFavicons,
                 history_backend_.get(),
                 icon_urls,
                 icon_types,
                 desired_size_in_dip,
                 desired_scale_factors,
                 results),
      base::Bind(&RunWithFaviconResults, callback, base::Owned(results)));
}

base::CancelableTaskTracker::TaskId HistoryService::GetFaviconsForURL(
    const GURL& page_url,
    int icon_types,
    int desired_size_in_dip,
    const std::vector<ui::ScaleFactor>& desired_scale_factors,
    const FaviconService::FaviconResultsCallback& callback,
    base::CancelableTaskTracker* tracker) {
  DCHECK(thread_checker_.CalledOnValidThread());

  std::vector<chrome::FaviconBitmapResult>* results =
      new std::vector<chrome::FaviconBitmapResult>();
  return tracker->PostTaskAndReply(
      thread_->message_loop_proxy().get(),
      FROM_HERE,
      base::Bind(&HistoryBackend::GetFaviconsForURL,
                 history_backend_.get(),
                 page_url,
                 icon_types,
                 desired_size_in_dip,
                 desired_scale_factors,
                 results),
      base::Bind(&RunWithFaviconResults, callback, base::Owned(results)));
}

base::CancelableTaskTracker::TaskId HistoryService::GetLargestFaviconForURL(
    const GURL& page_url,
    const std::vector<int>& icon_types,
    int minimum_size_in_pixels,
    const FaviconService::FaviconRawCallback& callback,
    base::CancelableTaskTracker* tracker) {
  DCHECK(thread_checker_.CalledOnValidThread());

  chrome::FaviconBitmapResult* result = new chrome::FaviconBitmapResult();
  return tracker->PostTaskAndReply(
      thread_->message_loop_proxy().get(),
      FROM_HERE,
      base::Bind(&HistoryBackend::GetLargestFaviconForURL,
                 history_backend_.get(),
                 page_url,
                 icon_types,
                 minimum_size_in_pixels,
                 result),
      base::Bind(&RunWithFaviconResult, callback, base::Owned(result)));
}

base::CancelableTaskTracker::TaskId HistoryService::GetFaviconForID(
    chrome::FaviconID favicon_id,
    int desired_size_in_dip,
    ui::ScaleFactor desired_scale_factor,
    const FaviconService::FaviconResultsCallback& callback,
    base::CancelableTaskTracker* tracker) {
  DCHECK(thread_checker_.CalledOnValidThread());

  std::vector<chrome::FaviconBitmapResult>* results =
      new std::vector<chrome::FaviconBitmapResult>();
  return tracker->PostTaskAndReply(
      thread_->message_loop_proxy().get(),
      FROM_HERE,
      base::Bind(&HistoryBackend::GetFaviconForID,
                 history_backend_.get(),
                 favicon_id,
                 desired_size_in_dip,
                 desired_scale_factor,
                 results),
      base::Bind(&RunWithFaviconResults, callback, base::Owned(results)));
}

base::CancelableTaskTracker::TaskId
HistoryService::UpdateFaviconMappingsAndFetch(
    const GURL& page_url,
    const std::vector<GURL>& icon_urls,
    int icon_types,
    int desired_size_in_dip,
    const std::vector<ui::ScaleFactor>& desired_scale_factors,
    const FaviconService::FaviconResultsCallback& callback,
    base::CancelableTaskTracker* tracker) {
  DCHECK(thread_checker_.CalledOnValidThread());

  std::vector<chrome::FaviconBitmapResult>* results =
      new std::vector<chrome::FaviconBitmapResult>();
  return tracker->PostTaskAndReply(
      thread_->message_loop_proxy().get(),
      FROM_HERE,
      base::Bind(&HistoryBackend::UpdateFaviconMappingsAndFetch,
                 history_backend_.get(),
                 page_url,
                 icon_urls,
                 icon_types,
                 desired_size_in_dip,
                 desired_scale_factors,
                 results),
      base::Bind(&RunWithFaviconResults, callback, base::Owned(results)));
}

void HistoryService::MergeFavicon(
    const GURL& page_url,
    const GURL& icon_url,
    chrome::IconType icon_type,
    scoped_refptr<base::RefCountedMemory> bitmap_data,
    const gfx::Size& pixel_size) {
  DCHECK(thread_checker_.CalledOnValidThread());
  if (!CanAddURL(page_url))
    return;

  ScheduleAndForget(PRIORITY_NORMAL, &HistoryBackend::MergeFavicon, page_url,
                    icon_url, icon_type, bitmap_data, pixel_size);
}

void HistoryService::SetFavicons(
    const GURL& page_url,
    chrome::IconType icon_type,
    const std::vector<chrome::FaviconBitmapData>& favicon_bitmap_data) {
  DCHECK(thread_checker_.CalledOnValidThread());
  if (!CanAddURL(page_url))
    return;

  ScheduleAndForget(PRIORITY_NORMAL, &HistoryBackend::SetFavicons, page_url,
      icon_type, favicon_bitmap_data);
}

void HistoryService::SetFaviconsOutOfDateForPage(const GURL& page_url) {
  DCHECK(thread_checker_.CalledOnValidThread());
  ScheduleAndForget(PRIORITY_NORMAL,
                    &HistoryBackend::SetFaviconsOutOfDateForPage, page_url);
}

void HistoryService::CloneFavicons(const GURL& old_page_url,
                                   const GURL& new_page_url) {
  DCHECK(thread_checker_.CalledOnValidThread());
  ScheduleAndForget(PRIORITY_NORMAL, &HistoryBackend::CloneFavicons,
                    old_page_url, new_page_url);
}

void HistoryService::SetImportedFavicons(
    const std::vector<ImportedFaviconUsage>& favicon_usage) {
  DCHECK(thread_checker_.CalledOnValidThread());
  ScheduleAndForget(PRIORITY_NORMAL,
                    &HistoryBackend::SetImportedFavicons, favicon_usage);
}

HistoryService::Handle HistoryService::QueryURL(
    const GURL& url,
    bool want_visits,
    CancelableRequestConsumerBase* consumer,
    const QueryURLCallback& callback) {
  DCHECK(thread_checker_.CalledOnValidThread());
  return Schedule(PRIORITY_UI, &HistoryBackend::QueryURL, consumer,
                  new history::QueryURLRequest(callback), url, want_visits);
}

// Downloads -------------------------------------------------------------------

// Handle creation of a download by creating an entry in the history service's
// 'downloads' table.
void HistoryService::CreateDownload(
    const history::DownloadRow& create_info,
    const HistoryService::DownloadCreateCallback& callback) {
  DCHECK(thread_) << "History service being called after cleanup";
  DCHECK(thread_checker_.CalledOnValidThread());
  PostTaskAndReplyWithResult(
      thread_->message_loop_proxy(), FROM_HERE,
      base::Bind(&HistoryBackend::CreateDownload, history_backend_.get(),
                 create_info),
      callback);
}

void HistoryService::GetNextDownloadId(
    const content::DownloadIdCallback& callback) {
  DCHECK(thread_) << "History service being called after cleanup";
  DCHECK(thread_checker_.CalledOnValidThread());
  PostTaskAndReplyWithResult(
      thread_->message_loop_proxy(), FROM_HERE,
      base::Bind(&HistoryBackend::GetNextDownloadId, history_backend_.get()),
      callback);
}

// Handle queries for a list of all downloads in the history database's
// 'downloads' table.
void HistoryService::QueryDownloads(
    const DownloadQueryCallback& callback) {
  DCHECK(thread_) << "History service being called after cleanup";
  DCHECK(thread_checker_.CalledOnValidThread());
  std::vector<history::DownloadRow>* rows =
    new std::vector<history::DownloadRow>();
  scoped_ptr<std::vector<history::DownloadRow> > scoped_rows(rows);
  // Beware! The first Bind() does not simply |scoped_rows.get()| because
  // base::Passed(&scoped_rows) nullifies |scoped_rows|, and compilers do not
  // guarantee that the first Bind's arguments are evaluated before the second
  // Bind's arguments.
  thread_->message_loop_proxy()->PostTaskAndReply(
      FROM_HERE,
      base::Bind(&HistoryBackend::QueryDownloads, history_backend_.get(), rows),
      base::Bind(callback, base::Passed(&scoped_rows)));
}

// Handle updates for a particular download. This is a 'fire and forget'
// operation, so we don't need to be called back.
void HistoryService::UpdateDownload(const history::DownloadRow& data) {
  DCHECK(thread_checker_.CalledOnValidThread());
  ScheduleAndForget(PRIORITY_NORMAL, &HistoryBackend::UpdateDownload, data);
}

void HistoryService::RemoveDownloads(const std::set<uint32>& ids) {
  DCHECK(thread_checker_.CalledOnValidThread());
  ScheduleAndForget(PRIORITY_NORMAL,
                    &HistoryBackend::RemoveDownloads, ids);
}

HistoryService::Handle HistoryService::QueryHistory(
    const base::string16& text_query,
    const history::QueryOptions& options,
    CancelableRequestConsumerBase* consumer,
    const QueryHistoryCallback& callback) {
  DCHECK(thread_checker_.CalledOnValidThread());
  return Schedule(PRIORITY_UI, &HistoryBackend::QueryHistory, consumer,
                  new history::QueryHistoryRequest(callback),
                  text_query, options);
}

HistoryService::Handle HistoryService::QueryRedirectsFrom(
    const GURL& from_url,
    CancelableRequestConsumerBase* consumer,
    const QueryRedirectsCallback& callback) {
  DCHECK(thread_checker_.CalledOnValidThread());
  return Schedule(PRIORITY_UI, &HistoryBackend::QueryRedirectsFrom, consumer,
      new history::QueryRedirectsRequest(callback), from_url);
}

HistoryService::Handle HistoryService::QueryRedirectsTo(
    const GURL& to_url,
    CancelableRequestConsumerBase* consumer,
    const QueryRedirectsCallback& callback) {
  DCHECK(thread_checker_.CalledOnValidThread());
  return Schedule(PRIORITY_NORMAL, &HistoryBackend::QueryRedirectsTo, consumer,
      new history::QueryRedirectsRequest(callback), to_url);
}

HistoryService::Handle HistoryService::GetVisibleVisitCountToHost(
    const GURL& url,
    CancelableRequestConsumerBase* consumer,
    const GetVisibleVisitCountToHostCallback& callback) {
  DCHECK(thread_checker_.CalledOnValidThread());
  return Schedule(PRIORITY_UI, &HistoryBackend::GetVisibleVisitCountToHost,
      consumer, new history::GetVisibleVisitCountToHostRequest(callback), url);
}

HistoryService::Handle HistoryService::QueryTopURLsAndRedirects(
    int result_count,
    CancelableRequestConsumerBase* consumer,
    const QueryTopURLsAndRedirectsCallback& callback) {
  DCHECK(thread_checker_.CalledOnValidThread());
  return Schedule(PRIORITY_NORMAL, &HistoryBackend::QueryTopURLsAndRedirects,
      consumer, new history::QueryTopURLsAndRedirectsRequest(callback),
      result_count);
}

HistoryService::Handle HistoryService::QueryMostVisitedURLs(
    int result_count,
    int days_back,
    CancelableRequestConsumerBase* consumer,
    const QueryMostVisitedURLsCallback& callback) {
  DCHECK(thread_checker_.CalledOnValidThread());
  return Schedule(PRIORITY_NORMAL, &HistoryBackend::QueryMostVisitedURLs,
                  consumer,
                  new history::QueryMostVisitedURLsRequest(callback),
                  result_count, days_back);
}

HistoryService::Handle HistoryService::QueryFilteredURLs(
    int result_count,
    const history::VisitFilter& filter,
    bool extended_info,
    CancelableRequestConsumerBase* consumer,
    const QueryFilteredURLsCallback& callback) {
  DCHECK(thread_checker_.CalledOnValidThread());
  return Schedule(PRIORITY_NORMAL,
                  &HistoryBackend::QueryFilteredURLs,
                  consumer,
                  new history::QueryFilteredURLsRequest(callback),
                  result_count, filter, extended_info);
}

void HistoryService::Observe(int type,
                             const content::NotificationSource& source,
                             const content::NotificationDetails& details) {
  DCHECK(thread_checker_.CalledOnValidThread());
  if (!thread_)
    return;

  switch (type) {
    case chrome::NOTIFICATION_HISTORY_URLS_DELETED: {
      // Update the visited link system for deleted URLs. We will update the
      // visited link system for added URLs as soon as we get the add
      // notification (we don't have to wait for the backend, which allows us to
      // be faster to update the state).
      //
      // For deleted URLs, we don't typically know what will be deleted since
      // delete notifications are by time. We would also like to be more
      // respectful of privacy and never tell the user something is gone when it
      // isn't. Therefore, we update the delete URLs after the fact.
      if (visitedlink_master_) {
        content::Details<history::URLsDeletedDetails> deleted_details(details);

        if (deleted_details->all_history) {
          visitedlink_master_->DeleteAllURLs();
        } else {
          URLIteratorFromURLRows iterator(deleted_details->rows);
          visitedlink_master_->DeleteURLs(&iterator);
        }
      }
      break;
    }

    case chrome::NOTIFICATION_TEMPLATE_URL_REMOVED:
      DeleteAllSearchTermsForKeyword(
          *(content::Details<TemplateURLID>(details).ptr()));
      break;

    default:
      NOTREACHED();
  }
}

void HistoryService::RebuildTable(
    const scoped_refptr<URLEnumerator>& enumerator) {
  DCHECK(thread_checker_.CalledOnValidThread());
  ScheduleAndForget(PRIORITY_NORMAL, &HistoryBackend::IterateURLs, enumerator);
}

bool HistoryService::Init(const base::FilePath& history_dir,
                          BookmarkService* bookmark_service,
                          bool no_db) {
  DCHECK(thread_checker_.CalledOnValidThread());
  if (!thread_->Start()) {
    Cleanup();
    return false;
  }

  history_dir_ = history_dir;
  bookmark_service_ = bookmark_service;
  no_db_ = no_db;

  if (profile_) {
    std::string languages =
        profile_->GetPrefs()->GetString(prefs::kAcceptLanguages);
    in_memory_url_index_.reset(
        new history::InMemoryURLIndex(profile_, history_dir_, languages));
    in_memory_url_index_->Init();
  }

  // Create the history backend.
  scoped_refptr<HistoryBackend> backend(
      new HistoryBackend(history_dir_,
                         new BackendDelegate(
                             weak_ptr_factory_.GetWeakPtr(),
                             base::ThreadTaskRunnerHandle::Get(),
                             profile_),
                         bookmark_service_));
  history_backend_.swap(backend);

  // There may not be a profile when unit testing.
  std::string languages;
  if (profile_) {
    PrefService* prefs = profile_->GetPrefs();
    languages = prefs->GetString(prefs::kAcceptLanguages);
  }
  ScheduleAndForget(PRIORITY_UI, &HistoryBackend::Init, languages, no_db_);

  if (visitedlink_master_) {
    bool result = visitedlink_master_->Init();
    DCHECK(result);
  }

  return true;
}

void HistoryService::ScheduleAutocomplete(HistoryURLProvider* provider,
                                          HistoryURLProviderParams* params) {
  DCHECK(thread_checker_.CalledOnValidThread());
  ScheduleAndForget(PRIORITY_UI, &HistoryBackend::ScheduleAutocomplete,
                    scoped_refptr<HistoryURLProvider>(provider), params);
}

void HistoryService::ScheduleTask(SchedulePriority priority,
                                  const base::Closure& task) {
  DCHECK(thread_checker_.CalledOnValidThread());
  CHECK(thread_);
  CHECK(thread_->message_loop());
  // TODO(brettw): Do prioritization.
  thread_->message_loop()->PostTask(FROM_HERE, task);
}

// static
bool HistoryService::CanAddURL(const GURL& url) {
  if (!url.is_valid())
    return false;

  // TODO: We should allow kChromeUIScheme URLs if they have been explicitly
  // typed.  Right now, however, these are marked as typed even when triggered
  // by a shortcut or menu action.
  if (url.SchemeIs(content::kJavaScriptScheme) ||
      url.SchemeIs(content::kChromeDevToolsScheme) ||
      url.SchemeIs(content::kChromeUIScheme) ||
      url.SchemeIs(content::kViewSourceScheme) ||
      url.SchemeIs(chrome::kChromeNativeScheme) ||
      url.SchemeIs(chrome::kChromeSearchScheme) ||
      url.SchemeIs(chrome::kDomDistillerScheme))
    return false;

  // Allow all about: and chrome: URLs except about:blank, since the user may
  // like to see "chrome://memory/", etc. in their history and autocomplete.
  if (url == GURL(content::kAboutBlankURL))
    return false;

  return true;
}

base::WeakPtr<HistoryService> HistoryService::AsWeakPtr() {
  DCHECK(thread_checker_.CalledOnValidThread());
  return weak_ptr_factory_.GetWeakPtr();
}

syncer::SyncMergeResult HistoryService::MergeDataAndStartSyncing(
    syncer::ModelType type,
    const syncer::SyncDataList& initial_sync_data,
    scoped_ptr<syncer::SyncChangeProcessor> sync_processor,
    scoped_ptr<syncer::SyncErrorFactory> error_handler) {
  DCHECK(thread_checker_.CalledOnValidThread());
  DCHECK_EQ(type, syncer::HISTORY_DELETE_DIRECTIVES);
  delete_directive_handler_.Start(this, initial_sync_data,
                                  sync_processor.Pass());
  return syncer::SyncMergeResult(type);
}

void HistoryService::StopSyncing(syncer::ModelType type) {
  DCHECK(thread_checker_.CalledOnValidThread());
  DCHECK_EQ(type, syncer::HISTORY_DELETE_DIRECTIVES);
  delete_directive_handler_.Stop();
}

syncer::SyncDataList HistoryService::GetAllSyncData(
    syncer::ModelType type) const {
  DCHECK(thread_checker_.CalledOnValidThread());
  DCHECK_EQ(type, syncer::HISTORY_DELETE_DIRECTIVES);
  // TODO(akalin): Keep track of existing delete directives.
  return syncer::SyncDataList();
}

syncer::SyncError HistoryService::ProcessSyncChanges(
    const tracked_objects::Location& from_here,
    const syncer::SyncChangeList& change_list) {
  delete_directive_handler_.ProcessSyncChanges(this, change_list);
  return syncer::SyncError();
}

syncer::SyncError HistoryService::ProcessLocalDeleteDirective(
    const sync_pb::HistoryDeleteDirectiveSpecifics& delete_directive) {
  DCHECK(thread_checker_.CalledOnValidThread());
  return delete_directive_handler_.ProcessLocalDeleteDirective(
      delete_directive);
}

void HistoryService::SetInMemoryBackend(
    scoped_ptr<history::InMemoryHistoryBackend> mem_backend) {
  DCHECK(thread_checker_.CalledOnValidThread());
  DCHECK(!in_memory_backend_) << "Setting mem DB twice";
  in_memory_backend_.reset(mem_backend.release());

  // The database requires additional initialization once we own it.
  in_memory_backend_->AttachToHistoryService(profile_);
}

void HistoryService::NotifyProfileError(sql::InitStatus init_status) {
  DCHECK(thread_checker_.CalledOnValidThread());
  ShowProfileErrorDialog(
      PROFILE_ERROR_HISTORY,
      (init_status == sql::INIT_FAILURE) ?
      IDS_COULDNT_OPEN_PROFILE_ERROR : IDS_PROFILE_TOO_NEW_ERROR);
}

void HistoryService::DeleteURL(const GURL& url) {
  DCHECK(thread_checker_.CalledOnValidThread());
  // We will update the visited links when we observe the delete notifications.
  ScheduleAndForget(PRIORITY_NORMAL, &HistoryBackend::DeleteURL, url);
}

void HistoryService::DeleteURLsForTest(const std::vector<GURL>& urls) {
  DCHECK(thread_checker_.CalledOnValidThread());
  // We will update the visited links when we observe the delete
  // notifications.
  ScheduleAndForget(PRIORITY_NORMAL, &HistoryBackend::DeleteURLs, urls);
}

void HistoryService::ExpireHistoryBetween(
    const std::set<GURL>& restrict_urls,
    Time begin_time,
    Time end_time,
    const base::Closure& callback,
    base::CancelableTaskTracker* tracker) {
  DCHECK(thread_);
  DCHECK(thread_checker_.CalledOnValidThread());
  DCHECK(history_backend_.get());
  tracker->PostTaskAndReply(thread_->message_loop_proxy().get(),
                            FROM_HERE,
                            base::Bind(&HistoryBackend::ExpireHistoryBetween,
                                       history_backend_,
                                       restrict_urls,
                                       begin_time,
                                       end_time),
                            callback);
}

void HistoryService::ExpireHistory(
    const std::vector<history::ExpireHistoryArgs>& expire_list,
    const base::Closure& callback,
    base::CancelableTaskTracker* tracker) {
  DCHECK(thread_);
  DCHECK(thread_checker_.CalledOnValidThread());
  DCHECK(history_backend_.get());
  tracker->PostTaskAndReply(
      thread_->message_loop_proxy().get(),
      FROM_HERE,
      base::Bind(&HistoryBackend::ExpireHistory, history_backend_, expire_list),
      callback);
}

void HistoryService::ExpireLocalAndRemoteHistoryBetween(
    const std::set<GURL>& restrict_urls,
    Time begin_time,
    Time end_time,
    const base::Closure& callback,
    base::CancelableTaskTracker* tracker) {
  // TODO(dubroy): This should be factored out into a separate class that
  // dispatches deletions to the proper places.

  history::WebHistoryService* web_history =
      WebHistoryServiceFactory::GetForProfile(profile_);
  if (web_history) {
    // TODO(dubroy): This API does not yet support deletion of specific URLs.
    DCHECK(restrict_urls.empty());

    delete_directive_handler_.CreateDeleteDirectives(
        std::set<int64>(), begin_time, end_time);

    // Attempt online deletion from the history server, but ignore the result.
    // Deletion directives ensure that the results will eventually be deleted.
    //
    // TODO(davidben): |callback| should not run until this operation completes
    // too.
    web_history->ExpireHistoryBetween(
        restrict_urls, begin_time, end_time,
        base::Bind(&ExpireWebHistoryComplete));
  }
  ExpireHistoryBetween(restrict_urls, begin_time, end_time, callback, tracker);
}

void HistoryService::BroadcastNotificationsHelper(
    int type,
    scoped_ptr<history::HistoryDetails> details) {
  DCHECK(thread_checker_.CalledOnValidThread());
  // TODO(evanm): this is currently necessitated by generate_profile, which
  // runs without a browser process. generate_profile should really create
  // a browser process, at which point this check can then be nuked.
  if (!g_browser_process)
    return;

  if (!thread_)
    return;

  // The source of all of our notifications is the profile. Note that this
  // pointer is NULL in unit tests.
  content::Source<Profile> source(profile_);

  // The details object just contains the pointer to the object that the
  // backend has allocated for us. The receiver of the notification will cast
  // this to the proper type.
  content::Details<history::HistoryDetails> det(details.get());

  content::NotificationService::current()->Notify(type, source, det);
}

void HistoryService::OnDBLoaded() {
  DCHECK(thread_checker_.CalledOnValidThread());
  backend_loaded_ = true;
  content::NotificationService::current()->Notify(
      chrome::NOTIFICATION_HISTORY_LOADED,
      content::Source<Profile>(profile_),
      content::Details<HistoryService>(this));
}

bool HistoryService::GetRowForURL(const GURL& url, history::URLRow* url_row) {
  DCHECK(thread_checker_.CalledOnValidThread());
  history::URLDatabase* db = InMemoryDatabase();
  return db && (db->GetRowForURL(url, url_row) != 0);
}

void HistoryService::AddVisitDatabaseObserver(
    history::VisitDatabaseObserver* observer) {
  DCHECK(thread_checker_.CalledOnValidThread());
  visit_database_observers_.AddObserver(observer);
}

void HistoryService::RemoveVisitDatabaseObserver(
    history::VisitDatabaseObserver* observer) {
  DCHECK(thread_checker_.CalledOnValidThread());
  visit_database_observers_.RemoveObserver(observer);
}

void HistoryService::NotifyVisitDBObserversOnAddVisit(
    const history::BriefVisitInfo& info) {
  DCHECK(thread_checker_.CalledOnValidThread());
  FOR_EACH_OBSERVER(history::VisitDatabaseObserver, visit_database_observers_,
                    OnAddVisit(info));
}