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comparison Core/Cache/MemoryCache.h @ 284:06aa7b7b6723

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implementation of a single-threaded cache mechanism
author Sebastien Jodogne <s.jodogne@gmail.com>
date Wed, 12 Dec 2012 15:40:18 +0100
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children 4031f73fe0e4
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283:c9977db00e1d 284:06aa7b7b6723
1 /**
2 * Orthanc - A Lightweight, RESTful DICOM Store
3 * Copyright (C) 2012 Medical Physics Department, CHU of Liege,
4 * Belgium
5 *
6 * This program is free software: you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License as
8 * published by the Free Software Foundation, either version 3 of the
9 * License, or (at your option) any later version.
10 *
11 * In addition, as a special exception, the copyright holders of this
12 * program give permission to link the code of its release with the
13 * OpenSSL project's "OpenSSL" library (or with modified versions of it
14 * that use the same license as the "OpenSSL" library), and distribute
15 * the linked executables. You must obey the GNU General Public License
16 * in all respects for all of the code used other than "OpenSSL". If you
17 * modify file(s) with this exception, you may extend this exception to
18 * your version of the file(s), but you are not obligated to do so. If
19 * you do not wish to do so, delete this exception statement from your
20 * version. If you delete this exception statement from all source files
21 * in the program, then also delete it here.
22 *
23 * This program is distributed in the hope that it will be useful, but
24 * WITHOUT ANY WARRANTY; without even the implied warranty of
25 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
26 * General Public License for more details.
27 *
28 * You should have received a copy of the GNU General Public License
29 * along with this program. If not, see <http://www.gnu.org/licenses/>.
30 **/
31
32
33 #pragma once
34
35 #include <memory>
36 #include "CacheIndex.h"
37 #include "ICachePageProvider.h"
38
39 namespace Orthanc
40 {
41 /**
42 * WARNING: This class is NOT thread-safe.
43 **/
44 class MemoryCache
45 {
46 private:
47 struct Page
48 {
49 std::string id_;
50 std::auto_ptr<IDynamicObject> content_;
51 };
52
53 ICachePageProvider& provider_;
54 size_t cacheSize_;
55 CacheIndex<std::string, Page*> index_;
56
57 Page& Load(const std::string& id);
58
59 public:
60 class Accessor
61 {
62 friend class MemoryCache;
63
64 private:
65 Page& element_;
66
67 Accessor(Page& element) :
68 element_(element)
69 {
70 }
71
72 public:
73 const std::string GetId() const
74 {
75 return element_.id_;
76 }
77
78 IDynamicObject& GetContent()
79 {
80 return *element_.content_;
81 }
82
83 const IDynamicObject& GetContent() const
84 {
85 return *element_.content_;
86 }
87 };
88
89 MemoryCache(ICachePageProvider& provider,
90 size_t cacheSize);
91
92 ~MemoryCache();
93
94 Accessor* Access(const std::string& id);
95 };
96 }