Componentize TopSites, TopSitesBackend, TopSitesDatabase

chrome/browser/history/top_sites.h

-// 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.
-
-#ifndef CHROME_BROWSER_HISTORY_TOP_SITES_H_
-#define CHROME_BROWSER_HISTORY_TOP_SITES_H_
-
-#include "base/basictypes.h"
-#include "base/callback.h"
-#include "base/gtest_prod_util.h"
-#include "base/observer_list.h"
-#include "base/task/cancelable_task_tracker.h"
-#include "components/history/core/browser/history_types.h"
-#include "components/history/core/common/thumbnail_score.h"
-#include "components/keyed_service/core/refcounted_keyed_service.h"
-#include "content/public/browser/notification_observer.h"
-#include "content/public/browser/notification_registrar.h"
-#include "third_party/skia/include/core/SkColor.h"
-#include "ui/gfx/image/image.h"
-
-class GURL;
-class Profile;
-
-namespace base {
-class FilePath;
-class RefCountedBytes;
-class RefCountedMemory;
-}
-
-namespace history {
-
-class TopSitesCache;
-class TopSitesObserver;
-
-// Interface for TopSites, which stores the data for the top "most visited"
-// sites. This includes a cache of the most visited data from history, as well
-// as the corresponding thumbnails of those sites.
-//
-// Some methods should only be called from the UI thread (see method
-// descriptions below). All others are assumed to be threadsafe.
-class TopSites : public RefcountedKeyedService,
-                 public content::NotificationObserver {
- public:
-  TopSites();
-
-  // Sets the given thumbnail for the given URL. Returns true if the thumbnail
-  // was updated. False means either the URL wasn't known to us, or we felt
-  // that our current thumbnail was superior to the given one. Should be called
-  // from the UI thread.
-  virtual bool SetPageThumbnail(const GURL& url,
-                                const gfx::Image& thumbnail,
-                                const ThumbnailScore& score) = 0;
-
-  // While testing the history system, we want to set the thumbnail to a piece
-  // of static memory.
-  virtual bool SetPageThumbnailToJPEGBytes(
-      const GURL& url,
-      const base::RefCountedMemory* memory,
-      const ThumbnailScore& score) = 0;
-
-  typedef base::Callback<void(const MostVisitedURLList&)>
-      GetMostVisitedURLsCallback;
-
-  // Returns a list of most visited URLs via a callback, if
-  // |include_forced_urls| is false includes only non-forced URLs. This may be
-  // invoked on any thread. NOTE: the callback is called immediately if we have
-  // the data cached. If data is not available yet, callback will later be
-  // posted to the thread called this function.
-  virtual void GetMostVisitedURLs(
-      const GetMostVisitedURLsCallback& callback,
-      bool include_forced_urls) = 0;
-
-  // Gets a thumbnail for a given page. Returns true iff we have the thumbnail.
-  // This may be invoked on any thread.
-  // If an exact thumbnail URL match fails, |prefix_match| specifies whether or
-  // not to try harder by matching the query thumbnail URL as URL prefix (as
-  // defined by UrlIsPrefix()).
-  // As this method may be invoked on any thread the ref count needs to be
-  // incremented before this method returns, so this takes a scoped_refptr*.
-  virtual bool GetPageThumbnail(
-      const GURL& url,
-      bool prefix_match,
-      scoped_refptr<base::RefCountedMemory>* bytes) = 0;
-
-  // Get a thumbnail score for a given page. Returns true iff we have the
-  // thumbnail score.  This may be invoked on any thread. The score will
-  // be copied to |score|.
-  virtual bool GetPageThumbnailScore(const GURL& url,
-                                     ThumbnailScore* score) = 0;
-
-  // Get a temporary thumbnail score for a given page. Returns true iff we
-  // have the thumbnail score. Useful when checking if we should update a
-  // thumbnail for a given page. The score will be copied to |score|.
-  virtual bool GetTemporaryPageThumbnailScore(const GURL& url,
-                                              ThumbnailScore* score) = 0;
-
-  // Asks TopSites to refresh what it thinks the top sites are. This may do
-  // nothing. Should be called from the UI thread.
-  virtual void SyncWithHistory() = 0;
-
-  // Blacklisted URLs
-
-  // Returns true if there is at least one item in the blacklist.
-  virtual bool HasBlacklistedItems() const = 0;
-
-  // Add a URL to the blacklist. Should be called from the UI thread.
-  virtual void AddBlacklistedURL(const GURL& url) = 0;
-
-  // Removes a URL from the blacklist. Should be called from the UI thread.
-  virtual void RemoveBlacklistedURL(const GURL& url) = 0;
-
-  // Returns true if the URL is blacklisted. Should be called from the UI
-  // thread.
-  virtual bool IsBlacklisted(const GURL& url) = 0;
-
-  // Clear the blacklist. Should be called from the UI thread.
-  virtual void ClearBlacklistedURLs() = 0;
-
-  // Query history service for the list of available thumbnails. Returns the
-  // task id for the request, or |base::CancelableTaskTracker::kBadTaskId| if a
-  // request could not be made. Public only for testing purposes.
-  virtual base::CancelableTaskTracker::TaskId StartQueryForMostVisited() = 0;
-
-  // Returns true if the given URL is known to the top sites service.
-  // This function also returns false if TopSites isn't loaded yet.
-  virtual bool IsKnownURL(const GURL& url) = 0;
-
-  // Follows the cached redirect chain to convert any URL to its
-  // canonical version. If no redirect chain is known for the URL,
-  // return it without modification.
-  virtual const std::string& GetCanonicalURLString(const GURL& url) const = 0;
-
-  // Returns true if the top sites list of non-forced URLs is full (i.e. we
-  // already have the maximum number of non-forced top sites).  This function
-  // also returns false if TopSites isn't loaded yet.
-  virtual bool IsNonForcedFull() = 0;
-
-  // Returns true if the top sites list of forced URLs is full (i.e. we already
-  // have the maximum number of forced top sites).  This function also returns
-  // false if TopSites isn't loaded yet.
-  virtual bool IsForcedFull() = 0;
-
-  virtual bool loaded() const = 0;
-
-  // Returns the set of prepopulate pages.
-  virtual MostVisitedURLList GetPrepopulatePages() = 0;
-
-  // Adds or updates a |url| for which we should force the capture of a
-  // thumbnail next time it's visited. If there is already a non-forced URL
-  // matching this |url| this call has no effect. Indicate this URL was laste
-  // forced at |time| so we can evict the older URLs when needed. Should be
-  // called from the UI thread.
-  virtual bool AddForcedURL(const GURL& url, const base::Time& time) = 0;
-
-  struct PrepopulatedPage {
-    // The string resource for the url.
-    int url_id;
-    // The string resource for the page title.
-    int title_id;
-    // The raw data resource for the favicon.
-    int favicon_id;
-    // The raw data resource for the thumbnail.
-    int thumbnail_id;
-    // The best color to highlight the page (should roughly match favicon).
-    SkColor color;
-  };
-
-  // Add Observer to the list.
-  void AddObserver(TopSitesObserver* observer);
-
-  // Remove Observer from the list.
-  void RemoveObserver(TopSitesObserver* observer);
-
- protected:
-  void NotifyTopSitesLoaded();
-  void NotifyTopSitesChanged();
-  ~TopSites() override;
-
- private:
-  ObserverList<TopSitesObserver, true> observer_list_;
-  friend class base::RefCountedThreadSafe<TopSites>;
-};
-
-#if defined(OS_ANDROID)
-const int kPrepopulatedPagesCount = 0;
-#else
-const int kPrepopulatedPagesCount = 2;
-#endif
-extern const TopSites::PrepopulatedPage
-    kPrepopulatedPages[kPrepopulatedPagesCount];
-
-}  // namespace history
-
-#endif  // CHROME_BROWSER_HISTORY_TOP_SITES_H_