Mercurial > hg > orthanc

comparison OrthancFramework/Sources/Cache/MemoryStringCache.h @ 5420:d37dff2c0028 am-new-cache

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Optimized the MemoryStringCache to prevent loading the same file multiple times if multiple users request the same file at the same time
author Alain Mazy <am@osimis.io>
date Mon, 13 Nov 2023 17:01:59 +0100
parents 0ea402b4d901
children c65e036d649b
comparison
equal deleted inserted replaced
5419:ac4e9fb87615 5420:d37dff2c0028
21 **/ 21 **/
22 22
23 23
24 #pragma once 24 #pragma once
25 25
26 #include "MemoryObjectCache.h" 26 #include "../OrthancFramework.h"
27 #include "ICacheable.h"
28 #include "LeastRecentlyUsedIndex.h"
29
30 #include <boost/thread/condition_variable.hpp>
31 #include <boost/thread/mutex.hpp>
32
27 33
28 namespace Orthanc 34 namespace Orthanc
29 { 35 {
30 /** 36 /**
31 * Facade object around "MemoryObjectCache" that caches a dictionary 37 * Class that caches a dictionary
32 * of strings, using the "fetch/add" paradigm of memcached. 38 * of strings, using the "fetch/add" paradigm of memcached.
39 *
40 * Starting from 1.12.2, if multiple clients are trying to access
41 * an inexistent item at the same time, only one of them will load it
42 * and the others will wait until the first one has loaded the data.
43 *
44 * The MemoryStringCache is only accessible through an Accessor.
33 * 45 *
34 * Note: this class is thread safe 46 * Note: this class is thread safe
35 **/ 47 **/
36 class ORTHANC_PUBLIC MemoryStringCache : public boost::noncopyable 48 class ORTHANC_PUBLIC MemoryStringCache : public boost::noncopyable
37 { 49 {
50 public:
51 class Accessor : public boost::noncopyable
52 {
53 MemoryStringCache& cache_;
54 bool shouldAdd_; // when this accessor is the one who should load and add the data
55 std::string keyToAdd_;
56 public:
57 Accessor(MemoryStringCache& cache);
58 ~Accessor();
59
60 bool Fetch(std::string& value, const std::string& key);
61 void Add(const std::string& key, const std::string& value);
62 void Add(const std::string& key,const char* buffer, size_t size);
63 };
64
38 private: 65 private:
39 class StringValue; 66 class StringValue;
40 67
41 MemoryObjectCache cache_; 68 boost::mutex cacheMutex_; // note: we can not use recursive_mutex with condition_variable
69 boost::condition_variable cacheCond_;
70 std::set<std::string> itemsBeingLoaded_;
71
72 size_t currentSize_;
73 size_t maxSize_;
74 LeastRecentlyUsedIndex<std::string, StringValue*> content_;
75
76 void Recycle(size_t targetSize);
42 77
43 public: 78 public:
79 MemoryStringCache();
80
81 ~MemoryStringCache();
82
44 size_t GetMaximumSize(); 83 size_t GetMaximumSize();
45 84
46 void SetMaximumSize(size_t size); 85 void SetMaximumSize(size_t size);
47 86
87 void Invalidate(const std::string& key);
88
89
90 private:
48 void Add(const std::string& key, 91 void Add(const std::string& key,
49 const std::string& value); 92 const std::string& value);
50 93
51 void Add(const std::string& key, 94 void Add(const std::string& key,
52 const void* buffer, 95 const void* buffer,
53 size_t size); 96 size_t size);
54 97
55 void Invalidate(const std::string& key);
56
57 bool Fetch(std::string& value, 98 bool Fetch(std::string& value,
58 const std::string& key); 99 const std::string& key);
100
101 void RemoveFromItemsBeingLoaded(const std::string& key);
102 void RemoveFromItemsBeingLoadedInternal(const std::string& key);
103
104 void AddToItemsBeingLoadedInternal(const std::string& key);
59 }; 105 };
60 } 106 }