1/*
2 * Copyright (c) 2004 Apple Computer, Inc. All Rights Reserved.
3 *
4 * @APPLE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. Please obtain a copy of the License at
10 * http://www.opensource.apple.com/apsl/ and read it before using this
11 * file.
12 *
13 * The Original Code and all software distributed under the License are
14 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
15 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
16 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
18 * Please see the License for the specific language governing rights and
19 * limitations under the License.
20 *
21 * @APPLE_LICENSE_HEADER_END@
22 */
23
24
25//
26// transactions - generic transaction frame support
27//
28#ifndef _H_TRANSACTIONS
29#define _H_TRANSACTIONS
30
31#include <security_utilities/utilities.h>
32#include <security_utilities/debugging.h>
33
34
35namespace Security {
36
37
38//
39// Implementation base class. Do not use directly.
40//
41class TransactionBase {
42public:
43	// what happens if this object gets destroyed?
44	enum Outcome {
45		successful,						// succeeds as set
46		cancelled,						// cancelled (rolled back)
47		conditional						// succeeds normally, cancelled on exception
48	};
49
50public:
51    virtual ~TransactionBase();
52
53	void outcome(Outcome oc)	{ mOutcome = oc; }
54	Outcome outcome() const		{ return mOutcome; }
55
56protected:
57	TransactionBase(Outcome outcome) : mOutcome(outcome) { }
58
59	Outcome finalOutcome() const;
60
61private:
62	Outcome mOutcome;					// current outcome setting
63};
64
65
66//
67// A ManagedTransaction will call methods begin() and end() on the Carrier object
68// it belongs to, and manage the "outcome" state and semantics automatically.
69// You would usually subclass this, though the class is complete in itself if you
70// need nothing else out of your transaction objects.
71//
72template <class Carrier>
73class ManagedTransaction : public TransactionBase {
74public:
75	ManagedTransaction(Carrier &carrier, Outcome outcome = conditional)
76		: TransactionBase(outcome), mCarrier(carrier)
77	{
78		carrier.begin();
79	}
80
81	~ManagedTransaction()
82	{
83		switch (finalOutcome()) {
84		case successful:
85			this->commitAction();
86			break;
87		case cancelled:
88			this->cancelAction();
89			break;
90		default:
91			assert(false);
92			break;
93		}
94	}
95
96protected:
97	virtual void commitAction()		{ mCarrier.end(); }
98	virtual void cancelAction()		{ mCarrier.cancel(); }
99
100	Carrier &mCarrier;
101};
102
103
104}	// end namespace Security
105
106
107#endif //_H_TRANSACTIONS
108