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

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

+// 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.
+
+#import "ios/chrome/browser/ui/history/history_entry_inserter.h"
+
+#import "base/ios/weak_nsobject.h"
+#include "base/mac/foundation_util.h"
+#include "base/mac/scoped_nsobject.h"
+#include "base/strings/sys_string_conversions.h"
+#include "base/time/time.h"
+#import "ios/chrome/browser/ui/collection_view/cells/collection_view_text_item.h"
+#import "ios/chrome/browser/ui/collection_view/collection_view_model.h"
+#import "ios/chrome/browser/ui/history/history_entry_item.h"
+#include "ios/chrome/browser/ui/history/history_util.h"
+#include "url/gurl.h"
+
+@interface HistoryEntryInserter () {
+  // Delegate for the HistoryEntryInserter.
+  base::WeakNSProtocol<id<HistoryEntryInserterDelegate>> _delegate;
+  // CollectionViewModel in which to insert history entries.
+  base::scoped_nsobject<CollectionViewModel> _collectionViewModel;
+  // The index of the first section to contain history entries.
+  NSInteger _firstSectionIndex;
+  // Number of assigned section identifiers.
+  NSInteger _sectionIdentifierCount;
+  // Sorted set of dates that have history entries.
+  base::scoped_nsobject<NSMutableOrderedSet> _dates;
+  // Mapping from dates to section identifiers.
+  base::scoped_nsobject<NSMutableDictionary> _sectionIdentifiers;
+}
+
+@end
+
+@implementation HistoryEntryInserter
+
+- (instancetype)initWithModel:(CollectionViewModel*)collectionViewModel {
+  if ((self = [super init])) {
+    _collectionViewModel.reset([collectionViewModel retain]);
+    _firstSectionIndex = [collectionViewModel numberOfSections];
+    _dates.reset([[NSMutableOrderedSet alloc] init]);
+    _sectionIdentifiers.reset([[NSMutableDictionary dictionary] retain]);
+  }
+  return self;
+}
+
+- (id<HistoryEntryInserterDelegate>)delegate {
+  return _delegate;
+}
+
+- (void)setDelegate:(id<HistoryEntryInserterDelegate>)delegate {
+  _delegate.reset(delegate);
+}
+
+- (void)insertHistoryEntryItem:(HistoryEntryItem*)item {
+  NSInteger sectionIdentifier =
+      [self sectionIdentifierForTimestamp:item.timestamp];
+
+  NSComparator objectComparator = ^(id obj1, id obj2) {
+    HistoryEntryItem* firstObject =
+        base::mac::ObjCCastStrict<HistoryEntryItem>(obj1);
+    HistoryEntryItem* secondObject =
+        base::mac::ObjCCastStrict<HistoryEntryItem>(obj2);
+    if ([firstObject isEqualToHistoryEntryItem:secondObject])
+      return NSOrderedSame;
+
+    // History entries are ordered from most to least recent.
+    if (firstObject.timestamp > secondObject.timestamp)
+      return NSOrderedAscending;
+    if (firstObject.timestamp < secondObject.timestamp)
+      return NSOrderedDescending;
+    return firstObject.URL < secondObject.URL ? NSOrderedAscending
+                                              : NSOrderedDescending;
+  };
+
+  NSArray* items =
+      [_collectionViewModel itemsInSectionWithIdentifier:sectionIdentifier];
+  NSRange range = NSMakeRange(0, [items count]);
+  // If the object is not already in the section, insert it.
+  if ([items indexOfObject:item
+             inSortedRange:range
+                   options:NSBinarySearchingFirstEqual
+           usingComparator:objectComparator] == NSNotFound) {
+    // Insert the object at the appropriate index to keep the section sorted.
+    NSUInteger index = [items indexOfObject:item
+                              inSortedRange:range
+                                    options:NSBinarySearchingInsertionIndex
+                            usingComparator:objectComparator];
+    [_collectionViewModel insertItem:item
+             inSectionWithIdentifier:sectionIdentifier
+                             atIndex:index];
+    NSIndexPath* indexPath = [NSIndexPath
+        indexPathForItem:index
+               inSection:[_collectionViewModel
+                             sectionForSectionIdentifier:sectionIdentifier]];
+    [self.delegate historyEntryInserter:self
+               didInsertItemAtIndexPath:indexPath];
+  }
+}
+
+- (NSUInteger)sectionIdentifierForTimestamp:(base::Time)timestamp {
+  base::TimeDelta timeDelta =
+      timestamp.LocalMidnight() - base::Time::UnixEpoch();
+  NSDate* date = [NSDate dateWithTimeIntervalSince1970:timeDelta.InSeconds()];
+
+  NSInteger sectionIdentifier =
+      [[_sectionIdentifiers objectForKey:date] integerValue];
+  // If there is a section identifier for the date, return it.
+  if (sectionIdentifier) {
+    return sectionIdentifier;
+  }
+
+  // Get the next section identifier, and add a section for date.
+  sectionIdentifier =
+      kSectionIdentifierEnumZero + _firstSectionIndex + _sectionIdentifierCount;
+  ++_sectionIdentifierCount;
+  [_sectionIdentifiers setObject:@(sectionIdentifier) forKey:date];
+
+  NSComparator comparator = ^(id obj1, id obj2) {
+    // Dates are ordered from most to least recent.
+    return [obj2 compare:obj1];
+  };
+  NSUInteger index = [_dates indexOfObject:date
+                             inSortedRange:NSMakeRange(0, [_dates count])
+                                   options:NSBinarySearchingInsertionIndex
+                           usingComparator:comparator];
+  [_dates insertObject:date atIndex:index];
+  NSInteger insertionIndex = _firstSectionIndex + index;
+  CollectionViewTextItem* header = [[[CollectionViewTextItem alloc]
+      initWithType:kItemTypeEnumZero] autorelease];
+  header.text =
+      base::SysUTF16ToNSString(history::GetRelativeDateLocalized(timestamp));
+  [_collectionViewModel insertSectionWithIdentifier:sectionIdentifier
+                                            atIndex:insertionIndex];
+  [_collectionViewModel setHeader:header
+         forSectionWithIdentifier:sectionIdentifier];
+  [self.delegate historyEntryInserter:self
+              didInsertSectionAtIndex:insertionIndex];
+  return sectionIdentifier;
+}
+
+- (void)removeSection:(NSInteger)sectionIndex {
+  NSUInteger sectionIdentifier =
+      [_collectionViewModel sectionIdentifierForSection:sectionIndex];
+
+  // Sections should not be removed unless there are no items in that section.
+  DCHECK(![[_collectionViewModel itemsInSectionWithIdentifier:sectionIdentifier]
+      count]);
+  [_collectionViewModel removeSectionWithIdentifier:sectionIdentifier];
+
+  NSEnumerator* dateEnumerator = [_sectionIdentifiers keyEnumerator];
+  NSDate* date = nil;
+  while ((date = [dateEnumerator nextObject])) {
+    if ([[_sectionIdentifiers objectForKey:date] unsignedIntegerValue] ==
+        sectionIdentifier) {
+      [_sectionIdentifiers removeObjectForKey:date];
+      [_dates removeObject:date];
+      break;
+    }
+  }
+  [self.delegate historyEntryInserter:self
+              didRemoveSectionAtIndex:sectionIndex];
+}
+
+@end