(NO NEED REVIEW) loading spinner background for bookmarks panel (iOS)

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

Index: ios/chrome/browser/ui/bookmarks/bookmark_collection_view.mm
diff --git a/ios/chrome/browser/ui/bookmarks/bookmark_collection_view.mm b/ios/chrome/browser/ui/bookmarks/bookmark_collection_view.mm
index 9e4992cce7fa8d4274c0400b0fe265e444b11ab1..11bdc7924bd3907355dff07cf9d5aa2186fb466a 100644
--- a/ios/chrome/browser/ui/bookmarks/bookmark_collection_view.mm
+++ b/ios/chrome/browser/ui/bookmarks/bookmark_collection_view.mm
@@ -21,20 +21,26 @@
 #include "components/favicon_base/fallback_icon_style.h"
 #include "components/favicon_base/favicon_types.h"
 #include "components/pref_registry/pref_registry_syncable.h"
+#include "components/signin/core/browser/signin_manager.h"
 #include "ios/chrome/browser/bookmarks/bookmark_model_factory.h"
 #include "ios/chrome/browser/bookmarks/bookmarks_utils.h"
 #include "ios/chrome/browser/experimental_flags.h"
 #include "ios/chrome/browser/favicon/ios_chrome_large_icon_service_factory.h"
 #include "ios/chrome/browser/pref_names.h"
+#include "ios/chrome/browser/signin/signin_manager_factory.h"
+#include "ios/chrome/browser/sync/sync_setup_service.h"
+#include "ios/chrome/browser/sync/sync_setup_service_factory.h"
 #import "ios/chrome/browser/ui/authentication/signin_promo_view.h"
 #import "ios/chrome/browser/ui/authentication/signin_promo_view_configurator.h"
 #import "ios/chrome/browser/ui/authentication/signin_promo_view_consumer.h"
 #import "ios/chrome/browser/ui/authentication/signin_promo_view_mediator.h"
 #import "ios/chrome/browser/ui/bookmarks/bookmark_collection_cells.h"
 #import "ios/chrome/browser/ui/bookmarks/bookmark_collection_view_background.h"
+#import "ios/chrome/browser/ui/bookmarks/bookmark_home_waiting_view.h"
 #import "ios/chrome/browser/ui/bookmarks/bookmark_promo_cell.h"
 #import "ios/chrome/browser/ui/bookmarks/bookmark_signin_promo_cell.h"
 #import "ios/chrome/browser/ui/bookmarks/bookmark_utils_ios.h"
+#import "ios/chrome/browser/ui/sync/synced_sessions_bridge.h"
 #include "ios/chrome/browser/ui/ui_util.h"
 #import "ios/chrome/browser/ui/uikit_ui_util.h"
 #include "ios/chrome/grit/ios_strings.h"
@@ -74,15 +80,10 @@ CGFloat rowMarginTablet = 24.0;
 CGFloat rowHeight = 48.0;
 // Minimal acceptable favicon size, in points.
 CGFloat minFaviconSizePt = 16;
-
-// Delay in seconds to which the empty background view will be shown when the
-// collection view is empty.
-// This delay should not be too small to let enough time to load bookmarks
-// from network.
-const NSTimeInterval kShowEmptyBookmarksBackgroundRefreshDelay = 1.0;
 }
 
 @interface BookmarkCollectionView ()<BookmarkPromoCellDelegate,
+                                     SyncedSessionsObserver,
                                      SigninPromoViewConsumer,
                                      UICollectionViewDataSource,
                                      UICollectionViewDelegateFlowLayout,
@@ -107,6 +108,9 @@ const NSTimeInterval kShowEmptyBookmarksBackgroundRefreshDelay = 1.0;
   std::map<IntegerPair, base::CancelableTaskTracker::TaskId> _faviconLoadTasks;
   // Task tracker used for async favicon loads.
   base::CancelableTaskTracker _faviconTaskTracker;
+
+  std::unique_ptr<synced_sessions::SyncedSessionsObserverBridge>
+      _syncedSessionsObserver;
 }
 
 // Redefined to be readwrite.
@@ -120,6 +124,9 @@ const NSTimeInterval kShowEmptyBookmarksBackgroundRefreshDelay = 1.0;
 // Background view of the collection view shown when there is no items.
 @property(nonatomic, strong)
     BookmarkCollectionViewBackground* emptyCollectionBackgroundView;
+// Background view showing a loading spinner.
+@property(nonatomic, strong)
+    BookmarkHomeWaitingView* loadingSpinnerBackgroundView;
 // Shadow to display over the content.
 @property(nonatomic, strong) UIView* shadow;
 
@@ -140,6 +147,7 @@ const NSTimeInterval kShowEmptyBookmarksBackgroundRefreshDelay = 1.0;
 @synthesize collectionView = _collectionView;
 @synthesize editing = _editing;
 @synthesize emptyCollectionBackgroundView = _emptyCollectionBackgroundView;
+@synthesize loadingSpinnerBackgroundView = _loadingSpinnerBackgroundView;
 @synthesize loader = _loader;
 @synthesize longPressRecognizer = _longPressRecognizer;
 @synthesize browserState = _browserState;
@@ -222,6 +230,7 @@ const NSTimeInterval kShowEmptyBookmarksBackgroundRefreshDelay = 1.0;
 
     [self setupViews];
     [self updateCollectionView];
+    [self initObserver];
   }
   return self;
 }
@@ -241,6 +250,7 @@ const NSTimeInterval kShowEmptyBookmarksBackgroundRefreshDelay = 1.0;
     [moi self];
   });
   _faviconTaskTracker.TryCancelAll();
+  [self deallocObserver];
 }
 
 #pragma mark - BookmarkHomePrimaryView
@@ -639,6 +649,17 @@ const NSTimeInterval kShowEmptyBookmarksBackgroundRefreshDelay = 1.0;
   [self.collectionView reloadData];
 }
 
+- (void)initObserver {
+  if (!_syncedSessionsObserver) {
+    _syncedSessionsObserver.reset(
+        new synced_sessions::SyncedSessionsObserverBridge(self, _browserState));
+  }
+}
+
+- (void)deallocObserver {
+  _syncedSessionsObserver.reset();
+}
+
 // Returns the bookmark node associated with |indexPath|.
 - (const BookmarkNode*)nodeAtIndexPath:(NSIndexPath*)indexPath {
   if (indexPath.section == self.folderSection)
@@ -896,21 +917,6 @@ const NSTimeInterval kShowEmptyBookmarksBackgroundRefreshDelay = 1.0;
 
 #pragma mark - empty background
 
-// Schedules showing or hiding the empty bookmarks background view if the
-// collection view is empty by calling showEmptyBackgroundIfNeeded after
-// kShowEmptyBookmarksBackgroundRefreshDelay.
-// Multiple call to this method will cancel previous scheduled call to
-// showEmptyBackgroundIfNeeded before scheduling a new one.
-- (void)scheduleEmptyBackgroundVisibilityUpdate {
-  [NSObject cancelPreviousPerformRequestsWithTarget:self
-                                           selector:@selector
-                                           (updateEmptyBackgroundVisibility)
-                                             object:nil];
-  [self performSelector:@selector(updateEmptyBackgroundVisibility)
-             withObject:nil
-             afterDelay:kShowEmptyBookmarksBackgroundRefreshDelay];
-}
-
 - (BOOL)isCollectionViewEmpty {
   BOOL collectionViewIsEmpty = YES;
   const NSInteger numberOfSections = [self numberOfSections];
@@ -923,13 +929,6 @@ const NSTimeInterval kShowEmptyBookmarksBackgroundRefreshDelay = 1.0;
   return collectionViewIsEmpty;
 }
 
-// Shows/hides empty bookmarks background view if the collections view is empty.
-- (void)updateEmptyBackgroundVisibility {
-  const BOOL showEmptyBackground =
-      [self isCollectionViewEmpty] && ![self shouldShowPromoCell];
-  [self setEmptyBackgroundVisible:showEmptyBackground];
-}
-
 // Shows/hides empty bookmarks background view with an animation.
 - (void)setEmptyBackgroundVisible:(BOOL)emptyBackgroundVisible {
   [UIView beginAnimations:@"alpha" context:NULL];
@@ -937,6 +936,59 @@ const NSTimeInterval kShowEmptyBookmarksBackgroundRefreshDelay = 1.0;
   [UIView commitAnimations];
 }
 
+// If the collection view is not empty, hide the empty bookmarks and loading
+// spinner background. If the collection view is empty, shows the loading
+// spinner background (if syncing) or the empty bookmarks background (if not
+// syncing).
+- (void)showEmptyOrLoadingSpinnerBackgroundIfNeeded {
+  const BOOL isEmpty =
+      [self isCollectionViewEmpty] && ![self shouldShowPromoCell];
+  if (!isEmpty) {
+    [self hideLoadingSpinnerBackground];
+    [self hideEmptyBackground];
+    return;
+  }
+  if ([self isSyncing]) {
+    [self showLoadingSpinnerBackground];
+    return;
+  }
+  [self showEmptyBackground];
+}
+
+// Shows loading spinner background view
+- (void)showLoadingSpinnerBackground {
+  if (!self.loadingSpinnerBackgroundView) {
+    BookmarkHomeWaitingView* loadingSpinnerBackgroundView =
+        [[BookmarkHomeWaitingView alloc] initWithFrame:CGRectZero];
+    self.loadingSpinnerBackgroundView = loadingSpinnerBackgroundView;
+    [self.loadingSpinnerBackgroundView startWaiting];
+    self.loadingSpinnerBackgroundView.autoresizingMask =
+        UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleWidth;
+    self.loadingSpinnerBackgroundView.alpha = 1;
+    self.loadingSpinnerBackgroundView.frame = self.collectionView.bounds;
+  }
+  self.collectionView.backgroundView = self.loadingSpinnerBackgroundView;
+  [self setEmptyBackgroundVisible:NO];
+}
+
+// Hides loading spinner background view
+- (void)hideLoadingSpinnerBackground {
+  if (self.loadingSpinnerBackgroundView) {
+    self.collectionView.backgroundView = self.emptyCollectionBackgroundView;
+    self.loadingSpinnerBackgroundView = nil;
+  }
+}
+
+- (void)showEmptyBackground {
+  [self hideLoadingSpinnerBackground];
+  [self setEmptyBackgroundVisible:YES];
+  self.collectionView.backgroundView = self.emptyCollectionBackgroundView;
+}
+
+- (void)hideEmptyBackground {
+  [self setEmptyBackgroundVisible:NO];
+}
+
 #pragma mark - UICollectionViewDataSource
 
 - (NSInteger)collectionView:(UICollectionView*)collectionView
@@ -945,12 +997,7 @@ const NSTimeInterval kShowEmptyBookmarksBackgroundRefreshDelay = 1.0;
       [self numberOfItemsInSection:section];
   const BOOL isCollectionViewEmpty = [self isCollectionViewEmpty];
   self.collectionView.scrollEnabled = !isCollectionViewEmpty;
-  if (isCollectionViewEmpty) {
-    [self scheduleEmptyBackgroundVisibilityUpdate];
-  } else {
-    // Hide empty bookmarks now.
-    [self setEmptyBackgroundVisible:NO];
-  }
+  [self showEmptyOrLoadingSpinnerBackgroundIfNeeded];
   return numberOfItemsInSection;
 }
 
@@ -959,12 +1006,7 @@ const NSTimeInterval kShowEmptyBookmarksBackgroundRefreshDelay = 1.0;
   const NSInteger numberOfSections = [self numberOfSections];
   const BOOL collectionViewIsEmpty = 0 == numberOfSections;
   self.collectionView.scrollEnabled = !collectionViewIsEmpty;
-  if (collectionViewIsEmpty) {
-    [self scheduleEmptyBackgroundVisibilityUpdate];
-  } else {
-    // Hide empty bookmarks now.
-    [self setEmptyBackgroundVisible:NO];
-  }
+  [self showEmptyOrLoadingSpinnerBackgroundIfNeeded];
   return numberOfSections;
 }
 
@@ -1281,4 +1323,36 @@ const NSTimeInterval kShowEmptyBookmarksBackgroundRefreshDelay = 1.0;
   return NO;
 }
 
+#pragma mark - Signin and syncing status
+
+- (BOOL)isSignedIn {
+  SigninManager* signin_manager =
+      ios::SigninManagerFactory::GetForBrowserState(_browserState);
+  return signin_manager->IsAuthenticated();
+}
+
+- (BOOL)isSyncing {
+  if (![self isSignedIn])
+    return false;
+
+  SyncSetupService* syncSetupService =
+      SyncSetupServiceFactory::GetForBrowserState(_browserState);
+
+  BOOL syncEnabled = syncSetupService->IsSyncEnabled();
+  BOOL noSyncError = (syncSetupService->GetSyncServiceState() ==
+                      SyncSetupService::kNoSyncServiceError);
+
+  return syncEnabled && noSyncError &&
+         !_syncedSessionsObserver->IsFirstSyncCycleCompleted();
+}
+
+#pragma mark - Exposed to the SyncedSessionsObserver
+
+- (void)reloadSessions {
+}
+
+- (void)onSyncStateChanged {
+  [self showEmptyOrLoadingSpinnerBackgroundIfNeeded];
+}
+
 @end