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ios/chrome/browser/ui/bookmarks/bookmark_all_collection_view.mm

Index: ios/chrome/browser/ui/bookmarks/bookmark_all_collection_view.mm
diff --git a/ios/chrome/browser/ui/bookmarks/bookmark_all_collection_view.mm b/ios/chrome/browser/ui/bookmarks/bookmark_all_collection_view.mm
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+// Copyright 2014 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/bookmarks/bookmark_all_collection_view.h"
+
+#include "base/logging.h"
+#include "base/mac/objc_property_releaser.h"
+#include "base/mac/scoped_nsobject.h"
+#include "base/strings/sys_string_conversions.h"
+#include "components/bookmarks/browser/bookmark_model.h"
+#include "ios/chrome/browser/bookmarks/bookmarks_utils.h"
+#import "ios/chrome/browser/ui/bookmarks/bookmark_collection_cells.h"
+#include "ios/chrome/browser/ui/bookmarks/bookmark_promo_cell.h"
+#import "ios/chrome/browser/ui/bookmarks/bookmark_utils_ios.h"
+#include "ui/base/l10n/l10n_util.h"
+#include "ui/base/models/tree_node_iterator.h"
+
+using bookmarks::BookmarkNode;
+
+namespace {
+typedef std::vector<const BookmarkNode*> NodeVector;
+// Each section of the collection view corresponds to a NodesSection object,
+// sorted by creation date.
+using bookmark_utils_ios::NodesSection;
+
+// There is sometimes a flurry of events from the bookmark model. When this
+// happens the data the collection view is displaying needs to be recalculated
+// and the collection view needs to be reloaded. The recalculation of the data
+// is expensive, so instead of doing the update over and over again the update
+// is done once and all other updates received during the same runloop event are
+// deferred to the next turn of the runloop (if everything is deferred this
+// unfortunately triggers a bug in the UICollectionView sometimes).
+// This enum tracks the state of the refresh. See -collectionViewNeedsUpdate
+// for the state machine.
+typedef enum { kNoUpdate = 0, kOneUpdateDone, kUpdateScheduled } UpdateState;
+}  // namespace
+
+@interface BookmarkAllCollectionView ()<BookmarkPromoCellDelegate> {
+  // A vector of vectors. Url nodes are segregated by month of creation.
+  ScopedVector<NodesSection> _nodesSectionVector;
+  // To avoid refreshing the internal model too often.
+  UpdateState _updateScheduled;
+  base::mac::ObjCPropertyReleaser _propertyReleaser_BookmarkAllCollectionView;
+}
+
+// Keep a reference to the promo cell to deregister as delegate.
+@property(nonatomic, retain) BookmarkPromoCell* promoCell;
+
+// Triggers an update of the collection, but delayed in order to coallesce a lot
+// of events into one update.
+- (void)collectionViewNeedsUpdate;
+
+@end
+
+@implementation BookmarkAllCollectionView
+
+@synthesize delegate = _delegate;
+@synthesize promoCell = _promoCell;
+
+- (instancetype)initWithBrowserState:(ios::ChromeBrowserState*)browserState
+                               frame:(CGRect)frame {
+  self = [super initWithBrowserState:browserState frame:frame];
+  if (self) {
+    _propertyReleaser_BookmarkAllCollectionView.Init(
+        self, [BookmarkAllCollectionView class]);
+    self.accessibilityIdentifier = @"bookmark_all_collection_view";
+    [self updateCollectionView];
+  }
+  return self;
+}
+
+- (void)dealloc {
+  _promoCell.delegate = nil;
+  [super dealloc];
+}
+
+- (void)updateCollectionView {
+  if (!self.bookmarkModel->loaded())
+    return;
+
+  // Regenerate the list of all bookmarks.
+  NodeVector allItems;
+  ui::TreeNodeIterator<const BookmarkNode> iterator(
+      self.bookmarkModel->root_node());
+
+  while (iterator.has_next()) {
+    const BookmarkNode* bookmark = iterator.Next();
+
+    if (bookmark->is_url())
+      allItems.push_back(bookmark);
+  }
+
+  // Perform segregation.
+  bookmark_utils_ios::segregateNodes(allItems, _nodesSectionVector);
+
+  [self cancelAllFaviconLoads];
+  [self.collectionView reloadData];
+}
+
+- (void)collectionViewNeedsUpdate {
+  switch (_updateScheduled) {
+    case kNoUpdate:
+      // If the collection view was not updated recently, update it now.
+      [self updateCollectionView];
+      _updateScheduled = kOneUpdateDone;
+      // And reset the state when going back to the main loop.
+      dispatch_async(dispatch_get_main_queue(), ^{
+        _updateScheduled = kNoUpdate;
+      });
+      break;
+    case kOneUpdateDone:
+      // An update was already done on this turn of the main loop, schedule the
+      // next update for later.
+      _updateScheduled = kUpdateScheduled;
+      dispatch_async(dispatch_get_main_queue(), ^{
+        if (_updateScheduled == kNoUpdate)
+          [self updateCollectionView];
+      });
+      break;
+    case kUpdateScheduled:
+      // Nothing to do.
+      break;
+  }
+}
+
+#pragma mark - BookmarkModelBridgeObserver Callbacks
+
+- (void)bookmarkModelLoaded {
+  [self updateCollectionView];
+}
+
+- (void)bookmarkNodeChanged:(const BookmarkNode*)bookmarkNode {
+  if (bookmarkNode->is_folder())
+    return;
+
+  // TODO(crbug.com/603661): Ideally, we would only reload the relevant index
+  // path. However, calling reloadItemsAtIndexPaths:(0,0) immediately after
+  // reloadData results in a exception: NSInternalInconsistencyException
+  // 'request for index path for global index 2147483645 ...'
+  // One solution would be to keep track of whether we've just called
+  // reloadData, but that requires experimentation to determine how long we have
+  // to wait before we can safely call reloadItemsAtIndexPaths.
+  [self updateCollectionView];
+}
+
+- (void)bookmarkNodeFaviconChanged:
+    (const bookmarks::BookmarkNode*)bookmarkNode {
+  // Only urls have favicons.
+  DCHECK(bookmarkNode->is_url());
+
+  // Update image of corresponding cell.
+  NSIndexPath* indexPath = [self indexPathForNode:bookmarkNode];
+  if (!indexPath)
+    return;
+
+  // Check that this cell is visible.
+  NSArray* visiblePaths = [self.collectionView indexPathsForVisibleItems];
+  if (![visiblePaths containsObject:indexPath])
+    return;
+
+  [self loadFaviconAtIndexPath:indexPath];
+}
+
+- (void)bookmarkNodeChildrenChanged:(const BookmarkNode*)bookmarkNode {
+  [self collectionViewNeedsUpdate];
+}
+
+- (void)bookmarkNode:(const BookmarkNode*)bookmarkNode
+     movedFromParent:(const BookmarkNode*)oldParent
+            toParent:(const BookmarkNode*)newParent {
+  [self updateCollectionView];
+}
+
+- (void)bookmarkNodeDeleted:(const BookmarkNode*)node
+                 fromFolder:(const BookmarkNode*)folder {
+  // Only remove the node from the list of all nodes. Since we also receive a
+  // 'bookmarkNodeChildrenChanged' callback, the collection view will be updated
+  // there.
+  for (NodesSection* nodesSection : _nodesSectionVector) {
+    NodeVector nodeVector = nodesSection->vector;
+    // If the node was in _nodesSectionVector, it is now invalid. In that case,
+    // remove it from _nodesSectionVector.
+    auto it = std::find(nodeVector.begin(), nodeVector.end(), node);
+    if (it != nodeVector.end()) {
+      nodeVector.erase(it);
+      nodesSection->vector = nodeVector;
+      break;
+    }
+  }
+}
+
+- (void)bookmarkModelRemovedAllNodes {
+  [self updateCollectionView];
+}
+
+#pragma mark - Parent class overrides that affect functionality
+
+- (void)collectionView:(UICollectionView*)collectionView
+       willDisplayCell:(UICollectionViewCell*)cell
+    forItemAtIndexPath:(NSIndexPath*)indexPath {
+  auto node = [self nodeAtIndexPath:indexPath];
+  if (node && node->type() == bookmarks::BookmarkNode::URL) {
+    [self loadFaviconAtIndexPath:indexPath];
+  }
+}
+
+- (void)didAddCellForEditingAtIndexPath:(NSIndexPath*)indexPath {
+  DCHECK(![self isPromoSection:indexPath.section]);
+  const BookmarkNode* node = [self nodeAtIndexPath:indexPath];
+  UICollectionViewCell* cell =
+      [self.collectionView cellForItemAtIndexPath:indexPath];
+  [self.delegate bookmarkCollectionView:self cell:cell addNodeForEditing:node];
+}
+
+- (void)didRemoveCellForEditingAtIndexPath:(NSIndexPath*)indexPath {
+  DCHECK(![self isPromoSection:indexPath.section]);
+  const BookmarkNode* node = [self nodeAtIndexPath:indexPath];
+  UICollectionViewCell* cell =
+      [self.collectionView cellForItemAtIndexPath:indexPath];
+  [self.delegate bookmarkCollectionView:self
+                                   cell:cell
+                   removeNodeForEditing:node];
+}
+
+- (BOOL)shouldSelectCellAtIndexPath:(NSIndexPath*)indexPath {
+  return ![self isPromoSection:indexPath.section];
+}
+
+- (void)didTapCellAtIndexPath:(NSIndexPath*)indexPath {
+  DCHECK(![self isPromoSection:indexPath.section]);
+  const BookmarkNode* node = [self nodeAtIndexPath:indexPath];
+  DCHECK(node);
+  RecordBookmarkLaunch(BOOKMARK_LAUNCH_LOCATION_ALL_ITEMS);
+  [self.delegate bookmarkCollectionView:self
+               selectedUrlForNavigation:node->url()];
+}
+
+- (void)didTapMenuButtonAtIndexPath:(NSIndexPath*)indexPath
+                             onView:(UIView*)view
+                            forCell:(BookmarkItemCell*)cell {
+  DCHECK(![self isPromoSection:indexPath.section]);
+  [self.delegate bookmarkCollectionView:self
+                   wantsMenuForBookmark:[self nodeAtIndexPath:indexPath]
+                                 onView:view
+                                forCell:cell];
+}
+
+- (bookmark_cell::ButtonType)buttonTypeForCellAtIndexPath:
+    (NSIndexPath*)indexPath {
+  DCHECK(![self isPromoSection:indexPath.section]);
+  if (self.editing)
+    return bookmark_cell::ButtonNone;
+  return bookmark_cell::ButtonMenu;
+}
+
+- (BOOL)allowLongPressForCellAtIndexPath:(NSIndexPath*)indexPath {
+  return [self isPromoSection:indexPath.section] ? NO : !self.editing;
+}
+
+- (void)didLongPressCell:(UICollectionViewCell*)cell
+             atIndexPath:(NSIndexPath*)indexPath {
+  DCHECK(![self isPromoSection:indexPath.section]);
+  [self.delegate bookmarkCollectionView:self
+                       didLongPressCell:cell
+                            forBookmark:[self nodeAtIndexPath:indexPath]];
+}
+
+- (BOOL)cellIsSelectedForEditingAtIndexPath:(NSIndexPath*)indexPath {
+  DCHECK(![self isPromoSection:indexPath.section]);
+
+  const BookmarkNode* node = [self nodeAtIndexPath:indexPath];
+  const std::set<const BookmarkNode*>& editingNodes =
+      [self.delegate nodesBeingEdited];
+  return editingNodes.find(node) != editingNodes.end();
+}
+
+- (const BookmarkNode*)nodeAtIndexPath:(NSIndexPath*)indexPath {
+  NSInteger section = indexPath.section;
+  if ([self isPromoSection:section])
+    return nullptr;
+
+  if ([self shouldShowPromoCell])
+    --section;
+  return _nodesSectionVector[section]->vector[indexPath.row];
+}
+
+- (NSIndexPath*)indexPathForNode:(const BookmarkNode*)bookmarkNode {
+  NSInteger section = 0;
+
+  // When showing promo cell, bookmarks start with section 1.
+  if ([self shouldShowPromoCell])
+    section = 1;
+
+  for (NodesSection* nodesSection : _nodesSectionVector) {
+    NodeVector nodeVector = nodesSection->vector;
+    NSInteger item = 0;
+    for (const BookmarkNode* node : nodeVector) {
+      if (bookmarkNode == node) {
+        return [NSIndexPath indexPathForItem:item inSection:section];
+      }
+      ++item;
+    }
+    ++section;
+  }
+
+  return nil;
+}
+
+#pragma mark - Parent class overrides that change UI
+
+// Parent class override.
+- (UIEdgeInsets)insetForSectionAtIndex:(NSInteger)section {
+  // Only return insets for non-empty sections.
+  NSInteger count = [self numberOfItemsInSection:section];
+  if (count == 0)
+    return UIEdgeInsetsZero;
+
+  // The last section needs special treatment.
+  UIEdgeInsets insets = [super insetForSectionAtIndex:section];
+  NSInteger sectionCount = [self.collectionView.dataSource
+      numberOfSectionsInCollectionView:self.collectionView];
+
+  if (section == sectionCount - 1) {
+    insets.top = 0;
+    return insets;
+  }
+
+  insets.top = 0;
+  insets.bottom = 0;
+  return insets;
+}
+
+// Parent class override.
+- (UICollectionViewCell*)cellAtIndexPath:(NSIndexPath*)indexPath {
+  if ([self isPromoSection:indexPath.section]) {
+    self.promoCell = [self.collectionView
+        dequeueReusableCellWithReuseIdentifier:[BookmarkPromoCell
+                                                   reuseIdentifier]
+                                  forIndexPath:indexPath];
+    self.promoCell.delegate = self;
+    return self.promoCell;
+  }
+
+  return [self cellForBookmark:[self nodeAtIndexPath:indexPath]
+                     indexPath:indexPath];
+}
+
+// Parent class override.
+- (CGSize)headerSizeForSection:(NSInteger)section {
+  if ([self isPromoSection:section])
+    return CGSizeZero;
+
+  return CGSizeMake(self.bounds.size.width, [BookmarkHeaderView handsetHeight]);
+}
+
+- (UICollectionReusableView*)headerAtIndexPath:(NSIndexPath*)indexPath {
+  NSInteger section = indexPath.section;
+  if ([self isPromoSection:section])
+    return nil;
+
+  if ([self shouldShowPromoCell])
+    --section;
+
+  BookmarkHeaderView* view = [self.collectionView
+      dequeueReusableSupplementaryViewOfKind:
+          UICollectionElementKindSectionHeader
+                         withReuseIdentifier:[BookmarkHeaderView
+                                                 reuseIdentifier]
+                                forIndexPath:indexPath];
+
+  NSString* title =
+      base::SysUTF8ToNSString(_nodesSectionVector[section]->timeRepresentation);
+  [view setTitle:title];
+  return view;
+}
+
+- (NSInteger)numberOfItemsInSection:(NSInteger)section {
+  if ([self isPromoSection:section])
+    return 1;
+
+  if ([self shouldShowPromoCell])
+    --section;
+  return _nodesSectionVector[section]->vector.size();
+}
+
+- (NSInteger)numberOfSections {
+  const BOOL showPromo = [self shouldShowPromoCell];
+  const NSInteger nodeSectionsCount = _nodesSectionVector.size();
+  return showPromo ? nodeSectionsCount + 1 : nodeSectionsCount;
+}
+
+#pragma mark - BookmarkPromoCellDelegate
+
+- (void)bookmarkPromoCellDidTapSignIn:(BookmarkPromoCell*)bookmarkPromoCell {
+  [self.delegate bookmarkCollectionViewShowSignIn:self];
+}
+
+- (void)bookmarkPromoCellDidTapDismiss:(BookmarkPromoCell*)bookmarkPromoCell {
+  [self.delegate bookmarkCollectionViewDismissPromo:self];
+}
+
+#pragma mark - Promo Cell
+
+- (BOOL)isPromoActive {
+  return [self.delegate bookmarkCollectionViewShouldShowPromoCell:self];
+}
+
+- (BOOL)shouldShowPromoCell {
+  // The promo cell is not shown in edit mode.
+  return !self.editing && [self isPromoActive];
+}
+
+@end