Upstream Chrome on iOS source code [9/11].

ios/chrome/browser/ui/tab_switcher/tab_switcher_model.h

+// Copyright 2015 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_TAB_SWITCHER_TAB_SWITCHER_MODEL_H_
+#define IOS_CHROME_BROWSER_UI_TAB_SWITCHER_TAB_SWITCHER_MODEL_H_
+
+#import <Foundation/Foundation.h>
+
+#include <string>
+#include "base/ios/block_types.h"
+#include "base/mac/scoped_nsobject.h"
+#import "ios/chrome/browser/tabs/tab_model_observer.h"
+#import "ios/chrome/browser/ui/ntp/recent_tabs/synced_sessions.h"
+#import "ios/chrome/browser/ui/ntp/recent_tabs/synced_sessions_bridge.h"
+#import "ios/chrome/browser/ui/tab_switcher/tab_model_snapshot.h"
+
+@class TabModel;
+@class TabSwitcherCache;
+
+enum class TabSwitcherSignInPanelsType {
+  PANEL_USER_SIGNED_OUT,
+  PANEL_USER_SIGNED_IN_SYNC_OFF,
+  PANEL_USER_SIGNED_IN_SYNC_IN_PROGRESS,
+  PANEL_USER_SIGNED_IN_SYNC_ON_NO_SESSIONS,
+  NO_PANEL,
+};
+
+namespace ios_internal {
+
+enum class SessionType {
+  OFF_THE_RECORD_SESSION,
+  REGULAR_SESSION,
+  DISTANT_SESSION
+};
+
+class ChromeBrowserState;
+
+// Returns true if the session type is a local session. A local session is a
+// "regular session" or an "off the record" session.
+bool IsLocalSession(SessionType sessionType);
+
+}  // namespace ios_internal
+
+// Protocol to observe changes to the TabSwitcherModel.
+@protocol TabSwitcherModelDelegate<NSObject>
+// Called when distant sessions were removed or inserted. |removedIndexes| and
+// |insertedIndexes| contains indexes in ascending order.
+- (void)distantSessionsRemovedAtSortedIndexes:(NSArray*)removedIndexes
+                      insertedAtSortedIndexes:(NSArray*)insertedIndexes;
+// Called when the distant session with the tag |tag| may need to be updated.
+- (void)distantSessionMayNeedUpdate:(std::string const&)tag;
+// Called when a local session of type |type| needs to be updated.
+- (void)localSessionMayNeedUpdate:(ios_internal::SessionType)type;
+// Called when the signed-in panel (if any) must change.
+- (void)signInPanelChangedTo:(TabSwitcherSignInPanelsType)panelType;
+// Called to retrieve the size of the item at the |index| in |session|.
+- (CGSize)sizeForItemAtIndex:(NSUInteger)index
+                   inSession:(ios_internal::SessionType)session;
+@end
+
+// This class serves as a bridge between Chrome-level data (CLD), and what is
+// presented on screen in the Tab Switcher.
+// The CLD is:
+// -The "distant sessions", i.e. the list of Chrome instances the user is
+//  signed-in, and the tabs each of the session contains.
+// -The non incognito/incognito tab models. Also known as the "local sessions".
+//
+// The TabSwitcher observes changes in the CLD, and takes snapshots of its
+// state.
+// Whenever the delegate can be notified, the TabSwitcher computes a diff
+// and notifies the delegate of the changes.
+@interface TabSwitcherModel : NSObject<SyncedSessionsObserver, TabModelObserver>
+
+@property(nonatomic, readonly) TabModel* mainTabModel;
+@property(nonatomic, readonly) TabModel* otrTabModel;
+
+// Default initializer. |browserState| must not be nullptr, |delegate| must not
+// be nil.
+- (instancetype)initWithBrowserState:(ios::ChromeBrowserState*)browserState
+                            delegate:(id<TabSwitcherModelDelegate>)delegate
+                        mainTabModel:(TabModel*)mainTabModel
+                         otrTabModel:(TabModel*)otrTabModel
+                           withCache:(TabSwitcherCache*)cache;
+// Sets the main and incognito tab models, and notify the delegate of changes,
+// if any. |mainTabModel| and |otrTabModel| can be nil.
+- (void)setMainTabModel:(TabModel*)mainTabModel
+            otrTabModel:(TabModel*)otrTabModel;
+// Returns the browserState.
+- (ios::ChromeBrowserState*)browserState;
+// Returns the latest data for the local session of type |type|.
+- (std::unique_ptr<TabModelSnapshot>)tabModelSnapshotForLocalSession:
+    (ios_internal::SessionType)type;
+// Returns the latest data for the distant session of tag |tag|.
+- (std::unique_ptr<const synced_sessions::DistantSession>)distantSessionForTag:
+    (std::string const&)tag;
+
+// Returns the current count of sessions including main and incognito.
+- (NSInteger)sessionCount;
+// Returns the current count of distant sessions.
+- (NSInteger)distantSessionCount;
+// Returns the type of the sign in panel.
+- (TabSwitcherSignInPanelsType)signInPanelType;
+// Returns the tag of the session at index |index|.
+- (std::string const&)tagOfDistantSessionAtIndex:(int)index;
+// Notifies the delegate that changes occured for the distant sessions.
+- (void)syncedSessionsChanged;
+@end
+
+#endif  // IOS_CHROME_BROWSER_UI_TAB_SWITCHER_TAB_SWITCHER_MODEL_H_