ios/web/crw_network_activity_indicator_manager.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef IOS_WEB_CRW_NETWORK_ACTIVITY_INDICATOR_MANAGER_H_
   6 #define IOS_WEB_CRW_NETWORK_ACTIVITY_INDICATOR_MANAGER_H_
   7
   8 #import <Foundation/Foundation.h>
   9
  10 // This class controls access to the network activity indicator across the
  11 // app. It provides a simple interface for clients to indicate they are
  12 // starting a network task and they would like the indicator shown, and to
  13 // indicate they have finished a network task.
  14 //
  15 // Clients are required to pass an NSString* to each method to identify
  16 // themselves. Separating clients into groups prevents a client from "stopping"
  17 // requests from other clients on accident, and makes those bugs easier to
  18 // track down. Specifically, the manager will immediately fail if the number
  19 // of tasks stopped for a group ever exceeds the number of tasks started for
  20 // that group. Clients are responsible for namespacing their group strings
  21 // properly. All methods must be called on the UI thread.
  22 @interface CRWNetworkActivityIndicatorManager : NSObject
  23
  24 // Returns the singleton CRWNetworkActivityIndicatorManager.
  25 + (CRWNetworkActivityIndicatorManager*)sharedInstance;
  26
  27 // Begins a single network task. The network activity indicator is guaranteed
  28 // to be shown after this finishes (if it isn't already). |group| must be
  29 // non-nil.
  30 - (void)startNetworkTaskForGroup:(NSString*)group;
  31
  32 // Stops a single network task. The network activity indicator may or may not
  33 // stop being shown once this finishes, depending on whether there are other
  34 // unstopped tasks or not. |group| must be non-nil, and have at least one
  35 // unstopped task.
  36 - (void)stopNetworkTaskForGroup:(NSString*)group;
  37
  38 // A convenience method for starting multiple network tasks at once. |group|
  39 // must be non-nil. |numTasks| must be greater than 0.
  40 - (void)startNetworkTasks:(NSUInteger)numTasks forGroup:(NSString*)group;
  41
  42 // A convenience method for stopping multiple network tasks at once. |group|
  43 // must be non-nil. |numTasks| must be greater than 0, and |numTasks| must be
  44 // less than or equal to the number of unstopped tasks in |group|.
  45 - (void)stopNetworkTasks:(NSUInteger)numTasks forGroup:(NSString*)group;
  46
  47 // A convenience method for stopping all network tasks for a group. |group|
  48 // must be non-nil. Can be called on any group at any time, regardless of
  49 // whether the group has any unstopped network tasks or not. Returns the number
  50 // of tasks stopped by this call.
  51 - (NSUInteger)clearNetworkTasksForGroup:(NSString*)group;
  52
  53 // Returns the number of unstopped network tasks for |group|. |group| must be
  54 // non-nil. Can be called on any group at any time, regardless of whether the
  55 // group has any unstopped network tasks or not.
  56 - (NSUInteger)numNetworkTasksForGroup:(NSString*)group;
  57
  58 // Returns the total number of unstopped network tasks, across all groups. This
  59 // method was added for testing only. Clients should never depend on this, and
  60 // should instead only be concerned with the number of unstopped network tasks
  61 // for the groups they control, which can be queried using
  62 // |-numNetworkTasksForGroup:|.
  63 - (NSUInteger)numTotalNetworkTasks;
  64
  65 @end
  66
  67 #endif  // IOS_WEB_CRW_NETWORK_ACTIVITY_INDICATOR_MANAGER_H_