chrome/installer/util/callback_work_item.h

   1 // Copyright (c) 2012 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 CHROME_INSTALLER_UTIL_CALLBACK_WORK_ITEM_H_
   6 #define CHROME_INSTALLER_UTIL_CALLBACK_WORK_ITEM_H_
   7
   8 #include "base/callback.h"
   9 #include "base/compiler_specific.h"
  10 #include "base/gtest_prod_util.h"
  11 #include "chrome/installer/util/work_item.h"
  12
  13 // A work item that invokes a callback on Do() and Rollback().  In the following
  14 // example, the function SomeWorkItemCallback() will be invoked when an item
  15 // list is processed.
  16 //
  17 // // A callback invoked to do some work.
  18 // bool SomeWorkItemCallback(const CallbackWorkItem& item) {
  19 //   if (item.IsRollback()) {
  20 //     // Rollback work goes here.  The return value is ignored in this case.
  21 //     return true;
  22 //   }
  23 //
  24 //   // Roll forward work goes here.  The return value indicates success/failure
  25 //   // of the item.
  26 //   return true;
  27 // }
  28 //
  29 // void SomeFunctionThatAddsItemsToAList(WorkItemList* item_list) {
  30 //   ...
  31 //   item_list->AddCallbackWorkItem(base::Bind(&SomeWorkItemCallback));
  32 //   ...
  33 // }
  34 class CallbackWorkItem : public WorkItem {
  35  public:
  36   virtual ~CallbackWorkItem();
  37
  38   virtual bool Do() override;
  39   virtual void Rollback() override;
  40
  41   bool IsRollback() const;
  42
  43  private:
  44   friend class WorkItem;
  45
  46   enum RollState {
  47     RS_UNDEFINED,
  48     RS_FORWARD,
  49     RS_BACKWARD,
  50   };
  51
  52   CallbackWorkItem(base::Callback<bool(const CallbackWorkItem&)> callback);
  53
  54   base::Callback<bool(const CallbackWorkItem&)> callback_;
  55   RollState roll_state_;
  56
  57   FRIEND_TEST_ALL_PREFIXES(CallbackWorkItemTest, TestFailure);
  58   FRIEND_TEST_ALL_PREFIXES(CallbackWorkItemTest, TestForwardBackward);
  59 };
  60
  61 #endif  // CHROME_INSTALLER_UTIL_CALLBACK_WORK_ITEM_H_