Upstream Chrome on iOS source code [5/11].

ios/chrome/browser/ui/history/history_entry_inserter.h

+// Copyright 2016 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 IOS_CHROME_BROWSER_UI_HISTORY_HISTORY_ENTRY_INSERTER_H_
+#define IOS_CHROME_BROWSER_UI_HISTORY_HISTORY_ENTRY_INSERTER_H_
+
+#import <Foundation/Foundation.h>
+
+#import "ios/chrome/browser/ui/collection_view/collection_view_model.h"
+
+namespace base {
+class Time;
+}
+@class CollectionViewModel;
+@class HistoryEntryInserter;
+@class HistoryEntryItem;
+
+// Delegate for HistoryEntryInserter. Provides callbacks for completion of item
+// and section insertion and deletion.
+@protocol HistoryEntryInserterDelegate<NSObject>
+// Invoked when the inserter has finished inserting an item.
+- (void)historyEntryInserter:(HistoryEntryInserter*)inserter
+    didInsertItemAtIndexPath:(NSIndexPath*)indexPath;
+// Invoked when the inserter has finished inserting a section.
+- (void)historyEntryInserter:(HistoryEntryInserter*)inserter
+     didInsertSectionAtIndex:(NSInteger)sectionIndex;
+// Invoked when the inserter has finished removing a section.
+- (void)historyEntryInserter:(HistoryEntryInserter*)inserter
+     didRemoveSectionAtIndex:(NSInteger)sectionIndex;
+@end
+
+// Object for ensuring history entry items are kept in order as they are added
+// to the CollectionViewModel.
+@interface HistoryEntryInserter : NSObject
+
+// Delegate for the HistoryEntryInserter. Receives callbacks upon item and
+// section insertion and removal.
+@property(nonatomic, assign) id<HistoryEntryInserterDelegate> delegate;
+
+// Designated initializer for HistoryEntryInserter. collectionViewModel is the
+// model into which entries are inserted. Sections for history entries are
+// appended to the model. Sections already in the model at initialization
+// of the inserter should not be removed, and sections should not be added
+// except by the inserter. Duplicate entries are not inserted.
+- (instancetype)initWithModel:(CollectionViewModel*)collectionViewModel
+    NS_DESIGNATED_INITIALIZER;
+- (instancetype)init NS_UNAVAILABLE;
+
+// Inserts a history entry into the model at the correct sorted index path.
+// History entries in the model are sorted from most to least recent, and
+// grouped into section by date. Duplicate entries are not inserted. Invokes
+// delegate callback when insertion is complete.
+- (void)insertHistoryEntryItem:(HistoryEntryItem*)item;
+
+// Returns section identifier for provided timestamp. Adds section for date if
+// not found, and invokes delegate callback.
+- (NSUInteger)sectionIdentifierForTimestamp:(base::Time)timestamp;
+
+// Removes section at |sectionIndex|, and invokes delegate callback when removal
+// is complete.
+- (void)removeSection:(NSInteger)sectionIndex;
+
+@end
+
+#endif  // IOS_CHROME_BROWSER_UI_HISTORY_HISTORY_ENTRY_INSERTER_H_