Experimental bookmark model based on tags.

chrome/browser/bookmarks/bookmark_tag_model.h

+// Copyright 2013 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_BOOKMARKS_BOOKMARK_TAG_MODEL_H_
+#define CHROME_BROWSER_BOOKMARKS_BOOKMARK_TAG_MODEL_H_
+
+#include "chrome/browser/bookmarks/bookmark_model.h"
+#include "chrome/browser/bookmarks/bookmark_model_observer.h"
+
+class BookmarkTagModelObserver;
+
+typedef string16 BookmarkTag;
+
+// BookmarTagModel provides a way to access and manipulate bookmarks in a
+// non-hierarchical way. BookmarkTagModel view the bookmarks as a flat list,
+// and each one can be marked with a collection of tags (tags are simply
+// strings).
+//
+// BookmarkTagModel converts on demand the data from an existing BookmarkModel
+// to its view of the world by considering all the titles of all the ancestors
+// as tags. This view is frozen on an individual bookmarks when the
+// BookmarkTagModel performs a change on the tags of this bookmarks.
+//
+// The Bookmark's meta info is used for storage.
+//
+// An observer may be attached to a BookmarkTagModel to observe relevant events.
+//
+// TODO(noyau): The meta info data is not preserved by copy/paste or drag and
+// drop, this means that bookmarks will loose their tag information if
+// manipulated that way.
+//
+class BookmarkTagModel : public BookmarkModelObserver {
+ public:
+  explicit BookmarkTagModel(BookmarkModel* bookmark_model);
+  virtual ~BookmarkTagModel();
+
+  // Returns true if the model finished loading.
+  bool loaded() const { return loaded_; }
+
+  // Add and remove observers on this object.
+  void AddObserver(BookmarkTagModelObserver* observer);
+  void RemoveObserver(BookmarkTagModelObserver* observer);
+
+  // Brackets an extensive set of changes, such as during import or sync, so
+  // observers can delay any expensive UI updates until it's finished.
+  class ExtensiveChanges {
+   public:
+    friend class BookmarkTagModel;
+    explicit ExtensiveChanges(BookmarkTagModel* model) : model_(model) {
+      model_->BeginExtensiveChanges();
+    }
+   private:
+    ~ExtensiveChanges() {
+      model_->EndExtensiveChanges();
+    }
+
+    BookmarkTagModel* model_;
+  };
+
+  // Returns true if this bookmark model is currently in a mode where extensive
+  // changes might happen, such as for import and sync. This is helpful for
+  // observers that are created after the mode has started, and want to check
+  // state during their own initializer.
+  bool IsDoingExtensiveChanges() const;
+
+  // Removes the given |BookmarkNode|. Observers are notified immediately.
+  void Remove(const BookmarkNode* bookmark);
+
+  // Removes all the bookmark nodes. Observers are only notified when all nodes
+  // have been removed. There is no notification for individual node removals.
+  void RemoveAll();
+
+  // Returns the favicon for |node|. If the favicon has not yet been
+  // loaded it is loaded and the observer of the model notified when done.
+  const gfx::Image& GetFavicon(const BookmarkNode* bookmark);
+
+  // Sets the title of |node|.
+  void SetTitle(const BookmarkNode* bookmark, const string16& title);
+
+  // Sets the URL of |node|.
+  void SetURL(const BookmarkNode* bookmark, const GURL& url);
+
+  // Sets the date added time of |node|.
+  void SetDateAdded(const BookmarkNode* bookmark, base::Time date_added);
+
+  // Returns the most recently added bookmark for the |url|. Returns NULL if
+  // |url| is not bookmarked.
+  const BookmarkNode* GetMostRecentlyAddedBookmarkForURL(const GURL& url);
+
+  // Creates a new bookmark.
+  const BookmarkNode* AddURL(const string16& title,
+                             const GURL& url,
+                             const std::set<BookmarkTag>& tags);
+
+  // Adds the |tags| to the tag list of the |bookmark|.
+  void AddTagsToBookmark(const std::set<BookmarkTag>& tags,
+                         const BookmarkNode* bookmark);
+
+  // Same but to a whole collection of |bookmarks|.
+  void AddTagsToBookmarks(const std::set<BookmarkTag>& tags,
+                          const std::set<const BookmarkNode*>& bookmarks);
+
+  // Remove the |tags| from the tag list of the |bookmark|. If the bookmark
+  // is not tagged with one or more of the tags, these are ignored.
+  void RemoveTagsFromBookmark(const std::set<BookmarkTag>& tags,
+                              const BookmarkNode* bookmark);
+
+  // Same but to a whole collection of |bookmarks|.
+  void RemoveTagsFromBookmarks(const std::set<BookmarkTag>& tags,
+                               const std::set<const BookmarkNode*>& bookmarks);
+
+  // Returns all the tags set on a specific |bookmark|.
+  std::set<BookmarkTag> GetTagsForBookmark(const BookmarkNode* bookmark);
+
+  // Returns the bookmarks marked with all the given |tags|.
+  std::set<const BookmarkNode*> BookmarksForTags(
+      const std::set<BookmarkTag>& tags);
+
+  // Returns the bookmarks marked with the given |tag|.
+  std::set<const BookmarkNode*> BookmarksForTag(const BookmarkTag& tag);
+
+  // Returns all tags related to the parent |tag|. If |tag| is null this method
+  // will returns and sort all tags in the system. A related tag is a tag used
+  // on one or more of the bookmarks tagged with |tag|. The returned tags are
+  // ordered from the most common to the rarest one.
+  std::vector<BookmarkTag> TagsRelatedToTag(const BookmarkTag& tag);
+
+  // All the BookmarkModelObserver methods. See there for details.
+  virtual void Loaded(BookmarkModel* model, bool ids_reassigned) OVERRIDE;
+  virtual void BookmarkModelBeingDeleted(BookmarkModel* model) OVERRIDE;
+  virtual void BookmarkNodeMoved(BookmarkModel* model,
+                                 const BookmarkNode* old_parent,
+                                 int old_index,
+                                 const BookmarkNode* new_parent,
+                                 int new_index) OVERRIDE;
+  virtual void BookmarkNodeAdded(BookmarkModel* model,
+                                 const BookmarkNode* parent,
+                                 int index) OVERRIDE;
+  virtual void OnWillRemoveBookmarks(BookmarkModel* model,
+                                     const BookmarkNode* parent,
+                                     int old_index,
+                                     const BookmarkNode* node) OVERRIDE;
+  virtual void BookmarkNodeRemoved(BookmarkModel* model,
+                                   const BookmarkNode* parent,
+                                   int old_index,
+                                   const BookmarkNode* node) OVERRIDE;
+  virtual void OnWillChangeBookmarkNode(BookmarkModel* model,
+                                        const BookmarkNode* node) OVERRIDE;
+  virtual void BookmarkNodeChanged(BookmarkModel* model,
+                                   const BookmarkNode* node) OVERRIDE;
+  virtual void OnWillChangeBookmarkMetaInfo(BookmarkModel* model,
+                                            const BookmarkNode* node) OVERRIDE;
+  virtual void BookmarkMetaInfoChanged(BookmarkModel* model,
+                                       const BookmarkNode* node) OVERRIDE;
+  virtual void BookmarkNodeFaviconChanged(BookmarkModel* model,
+                                          const BookmarkNode* node) OVERRIDE;
+  virtual void OnWillReorderBookmarkNode(BookmarkModel* model,
+                                         const BookmarkNode* node) OVERRIDE;
+  virtual void BookmarkNodeChildrenReordered(BookmarkModel* model,
+                                             const BookmarkNode* node) OVERRIDE;
+  virtual void ExtensiveBookmarkChangesBeginning(BookmarkModel* model) OVERRIDE;
+  virtual void ExtensiveBookmarkChangesEnded(BookmarkModel* model) OVERRIDE;
+  virtual void OnWillRemoveAllBookmarks(BookmarkModel* model) OVERRIDE;
+  virtual void BookmarkAllNodesRemoved(BookmarkModel* model) OVERRIDE;
+
+ private:
+  // Notifies the observers that an extensive set of changes is about to happen,
+  // such as during import or sync, so they can delay any expensive UI updates
+  // until it's finished.
+  void BeginExtensiveChanges();
+  void EndExtensiveChanges();
+
+  // Encode the tags in a format suitable for the BookmarkNode's metaInfo and
+  // set or replace the value.
+  void SetTagsOnBookmark(const std::set<BookmarkTag>& tags,
+                             const BookmarkNode* bookmark);
+
+  // Build the caches of tag to bookmarks and bookmarks to tag for faster
+  // access to the data. Load() is called from the constructor if possible, or
+  // as soon as possible after that.
+  void Load();
+
+  // Discard tag information for all descendants of a given folder node and
+  // rebuild the cache for them.
+  void ReloadDescendants(const BookmarkNode* folder);
+
+  // Clear the local cache of all mentions of |bookmark|.
+  void RemoveBookmark(const BookmarkNode* bookmark);
+
+  // Extract the tags from |bookmark| and insert it in the local cache.
+  void LoadBookmark(const BookmarkNode* bookmark);
+
+  // The model from where the data is permanently stored.
+  BookmarkModel* bookmark_model_;
+
+  // True if the model is fully loaded.
+  bool loaded_;
+
+  // The observers.
+  ObserverList<BookmarkTagModelObserver> observers_;
+
+  // Local cache for quick access.
+  std::map<const BookmarkTag, std::set<const BookmarkNode*> > tag_to_bookmarks_;
+  std::map<const BookmarkNode*, std::set<BookmarkTag> > bookmark_to_tags_;
+
+  // Set to true during the creation of a new bookmark in order to send only the
+  // proper notification.
+  bool inhibit_change_notifications_;
+
+  DISALLOW_COPY_AND_ASSIGN(BookmarkTagModel);
+};
+
+#endif  // CHROME_BROWSER_BOOKMARKS_BOOKMARK_TAG_MODEL_H_