conditional_work_item_list.h revision 5821806d5e7f356e8fa4b058a389a808ea183019 
1// Copyright (c) 2011 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_CONDITIONAL_WORK_ITEM_LIST_H_
6#define CHROME_INSTALLER_UTIL_CONDITIONAL_WORK_ITEM_LIST_H_
7
8#include "chrome/installer/util/work_item_list.h"
9
10#include "base/file_path.h"
11#include "base/memory/scoped_ptr.h"
12
13// A WorkItemList subclass that permits conditionally executing a set of
14// WorkItems.
15class ConditionalWorkItemList : public WorkItemList {
16 public:
17  explicit ConditionalWorkItemList(Condition* condition);
18  virtual ~ConditionalWorkItemList();
19
20  // If condition_->ShouldRun() returns true, then execute the items in this
21  // list and return true iff they all succeed. If condition_->ShouldRun()
22  // returns false, does nothing and returns true.
23  virtual bool Do();
24
25  // Does a rollback of the items (if any) that were run in Do.
26  virtual void Rollback();
27
28 protected:
29  // Pointer to a Condition that is used to determine whether to run this
30  // WorkItemList.
31  scoped_ptr<Condition> condition_;
32};
33
34
35// Pre-defined conditions:
36//------------------------------------------------------------------------------
37class ConditionRunIfFileExists : public WorkItem::Condition {
38 public:
39  explicit ConditionRunIfFileExists(const FilePath& key_path)
40      : key_path_(key_path) {}
41  bool ShouldRun() const;
42
43 private:
44  FilePath key_path_;
45};
46
47// Condition class that inverts the ShouldRun result of another Condition.
48// This class assumes ownership of original_condition.
49class Not : public WorkItem::Condition {
50 public:
51   explicit Not(WorkItem::Condition* original_condition)
52     : original_condition_(original_condition) {}
53  bool ShouldRun() const;
54
55 private:
56  scoped_ptr<WorkItem::Condition> original_condition_;
57};
58
59
60#endif  // CHROME_INSTALLER_UTIL_CONDITIONAL_WORK_ITEM_LIST_H_
61