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1 : : // Copyright (C) 2010 Internet Systems Consortium, Inc. ("ISC")
2 : : //
3 : : // Permission to use, copy, modify, and/or distribute this software for any
4 : : // purpose with or without fee is hereby granted, provided that the above
5 : : // copyright notice and this permission notice appear in all copies.
6 : : //
7 : : // THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
8 : : // REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
9 : : // AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
10 : : // INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
11 : : // LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
12 : : // OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
13 : : // PERFORMANCE OF THIS SOFTWARE.
14 : :
15 : : #ifndef __RRSET_CACHE_H
16 : : #define __RRSET_CACHE_H
17 : :
18 : : #include <cache/rrset_entry.h>
19 : : #include <nsas/hash_table.h>
20 : :
21 : : #include <util/lru_list.h>
22 : :
23 : : using namespace isc::nsas;
24 : :
25 : : namespace isc {
26 : : namespace cache {
27 : :
28 : : class RRsetEntry;
29 : :
30 : : /// \brief RRset Cache
31 : : /// The object of RRsetCache represented the cache for class-specific
32 : : /// RRsets.
33 : : ///
34 : : /// \todo The rrset cache class should provide the interfaces for
35 : : /// loading, dumping and resizing.
36 : : class RRsetCache{
37 : : ///
38 : : /// \name Constructors and Destructor
39 : : ///
40 : : /// Note: The copy constructor and the assignment operator are intentionally
41 : : /// defined as private to make it uncopyable
42 : : //@{
43 : : private:
44 : : RRsetCache(const RRsetCache&);
45 : : RRsetCache& operator=(const RRsetCache&);
46 : : public:
47 : : /// \brief Constructor and Destructor
48 : : ///
49 : : /// \param cache_size the size of rrset cache.
50 : : /// \param rrset_class the class of rrset cache.
51 : : RRsetCache(uint32_t cache_size, uint16_t rrset_class);
52 [ + - ]: 105 : virtual ~RRsetCache() {
53 [ + - ]: 105 : rrset_lru_.clear(); // Clear the rrset entries in the list.
54 : 204 : }
55 : : //@}
56 : :
57 : : /// \brief Look up rrset in cache.
58 : : ///
59 : : /// \param qname The query name to look up
60 : : /// \param qtype The query type
61 : : /// \return return the shared_ptr of rrset entry if it can be
62 : : /// found in the cache, or else, return NULL.
63 : : RRsetEntryPtr lookup(const isc::dns::Name& qname,
64 : : const isc::dns::RRType& qtype);
65 : :
66 : : /// \brief Update RRset Cache
67 : : /// Update the rrset entry in the cache with the new one.
68 : : /// If the rrset has expired or doesn't exist in the cache,
69 : : /// it will be added directly. It may be ingored if the new
70 : : /// rrset is not more authoritative than the old rrset in cache.
71 : : ///
72 : : /// \param rrset The new rrset used to update cache.
73 : : /// \param level trustworthiness of the rrset.
74 : : /// \return return the rrset entry in the cache, it may be the
75 : : /// new added rrset entry or existed one if it is not replaced.
76 : : RRsetEntryPtr update(const isc::dns::AbstractRRset& rrset,
77 : : const RRsetTrustLevel& level);
78 : :
79 : : /// \short Protected memebers, so they can be accessed by tests.
80 : : protected:
81 : : uint16_t class_; // The class of the rrset cache.
82 : : isc::nsas::HashTable<RRsetEntry> rrset_table_;
83 : : isc::util::LruList<RRsetEntry> rrset_lru_;
84 : : };
85 : :
86 : : typedef boost::shared_ptr<RRsetCache> RRsetCachePtr;
87 : : typedef boost::shared_ptr<const RRsetCache> ConstRRsetCachePtr;
88 : :
89 : : } // namespace cache
90 : : } // namespace isc
91 : :
92 : : #endif // __RRSET_CACHE_H
93 : :
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