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528b2c61 | 1 | /* |
528b2c61 | 2 | * |
3 | * SQUID Web Proxy Cache http://www.squid-cache.org/ | |
4 | * ---------------------------------------------------------- | |
5 | * | |
6 | * Squid is the result of efforts by numerous individuals from | |
7 | * the Internet community; see the CONTRIBUTORS file for full | |
8 | * details. Many organizations have provided support for Squid's | |
9 | * development; see the SPONSORS file for full details. Squid is | |
10 | * Copyrighted (C) 2001 by the Regents of the University of | |
11 | * California; see the COPYRIGHT file for full details. Squid | |
12 | * incorporates software developed and/or copyrighted by other | |
13 | * sources; see the CREDITS file for full details. | |
14 | * | |
15 | * This program is free software; you can redistribute it and/or modify | |
16 | * it under the terms of the GNU General Public License as published by | |
17 | * the Free Software Foundation; either version 2 of the License, or | |
18 | * (at your option) any later version. | |
26ac0430 | 19 | * |
528b2c61 | 20 | * This program is distributed in the hope that it will be useful, |
21 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
22 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
23 | * GNU General Public License for more details. | |
26ac0430 | 24 | * |
528b2c61 | 25 | * You should have received a copy of the GNU General Public License |
26 | * along with this program; if not, write to the Free Software | |
27 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA. | |
28 | * | |
29 | */ | |
528b2c61 | 30 | #ifndef SQUID_TYPELENGTHVALUE_H |
31 | #define SQUID_TYPELENGTHVALUE_H | |
32 | ||
33 | class StoreEntry; | |
62e76326 | 34 | |
e1f7507e | 35 | // WTF? |
528b2c61 | 36 | typedef class StoreMeta tlv; |
62e76326 | 37 | |
e1f7507e AJ |
38 | /** |
39 | \ingroup SwapStoreAPI | |
40 | \todo AYJ: for critical lists like this we should use A=64,B=65 etc to enforce and reserve values. | |
41 | \note NOTE! We must preserve the order of this list! | |
42 | * | |
43 | \section StoreSwapMeta Store "swap meta" Description | |
44 | \par | |
45 | * "swap meta" refers to a section of meta data stored at the beginning | |
46 | * of an object that is stored on disk. This meta data includes information | |
47 | * such as the object's cache key (MD5), URL, and part of the StoreEntry | |
48 | * structure. | |
49 | * | |
50 | \par | |
51 | * The meta data is stored using a TYPE-LENGTH-VALUE format. That is, | |
52 | * each chunk of meta information consists of a TYPE identifier, a | |
53 | * LENGTH field, and then the VALUE (which is LENGTH octets long). | |
54 | */ | |
55 | enum { | |
56 | /** | |
57 | * Just a placeholder for the zeroth value. It is never used on disk. | |
58 | */ | |
59 | STORE_META_VOID, | |
60 | ||
61 | /** | |
62 | \deprecated | |
63 | * This represents the case when we use the URL as the cache | |
64 | * key, as Squid-1.1 does. Currently we don't support using | |
65 | * a URL as a cache key, so this is not used. | |
66 | */ | |
67 | STORE_META_KEY_URL, | |
68 | ||
69 | /** | |
70 | \deprecated | |
71 | * For a brief time we considered supporting SHA (secure | |
72 | * hash algorithm) as a cache key. Nobody liked it, and | |
73 | * this type is not currently used. | |
74 | */ | |
75 | STORE_META_KEY_SHA, | |
76 | ||
77 | /** | |
78 | * This represents the MD5 cache key that Squid currently uses. | |
79 | * When Squid opens a disk file for reading, it can check that | |
80 | * this MD5 matches the MD5 of the user's request. If not, then | |
81 | * something went wrong and this is probably the wrong object. | |
82 | */ | |
83 | STORE_META_KEY_MD5, | |
84 | ||
85 | /** | |
86 | * The object's URL. This also may be matched against a user's | |
87 | * request for cache hits to make sure we got the right object. | |
88 | */ | |
89 | STORE_META_URL, | |
90 | ||
91 | /** | |
92 | * This is the "standard metadata" for an object. | |
93 | * Really its just this middle chunk of the StoreEntry structure: | |
94 | \code | |
95 | time_t timestamp; | |
96 | time_t lastref; | |
97 | time_t expires; | |
98 | time_t lastmod; | |
f45dd259 AJ |
99 | uint64_t swap_file_sz; |
100 | uint16_t refcount; | |
101 | uint16_t flags; | |
e1f7507e AJ |
102 | \endcode |
103 | */ | |
104 | STORE_META_STD, | |
105 | ||
106 | /** | |
107 | * Reserved for future hit-metering (RFC 2227) stuff | |
108 | */ | |
109 | STORE_META_HITMETERING, | |
110 | ||
111 | /// \todo DOCS: document. | |
112 | STORE_META_VALID, | |
113 | ||
114 | /** | |
115 | * Stores Vary request headers | |
116 | */ | |
117 | STORE_META_VARY_HEADERS, | |
118 | ||
119 | /** | |
120 | * Updated version of STORE_META_STD, with support for >2GB objects. | |
121 | * As STORE_META_STD except that the swap_file_sz is a 64-bit integer instead of 32-bit. | |
122 | */ | |
123 | STORE_META_STD_LFS, | |
124 | ||
e1f7507e AJ |
125 | STORE_META_OBJSIZE, |
126 | ||
127 | STORE_META_STOREURL, /* the store url, if different to the normal URL */ | |
128 | STORE_META_VARY_ID, /* Unique ID linking variants */ | |
129 | STORE_META_END | |
130 | }; | |
131 | ||
132 | /// \ingroup SwapStoreAPI | |
62e76326 | 133 | class StoreMeta |
134 | { | |
528b2c61 | 135 | public: |
528b2c61 | 136 | static bool validType(char); |
137 | static int const MaximumTLVLength; | |
138 | static int const MinimumTLVLength; | |
e1f7507e | 139 | static StoreMeta *Factory(char type, size_t len, void const *value); |
528b2c61 | 140 | static StoreMeta **Add(StoreMeta **tail, StoreMeta *aNode); |
e1f7507e | 141 | static void FreeList(StoreMeta **head); |
62e76326 | 142 | |
528b2c61 | 143 | virtual char getType() const = 0; |
144 | virtual bool validLength(int) const; | |
145 | virtual bool checkConsistency(StoreEntry *) const; | |
26ac0430 | 146 | virtual ~StoreMeta() {} |
62e76326 | 147 | |
528b2c61 | 148 | int length; |
149 | void *value; | |
150 | tlv *next; | |
528b2c61 | 151 | }; |
152 | ||
e1f7507e | 153 | /// \ingroup SwapStoreAPI |
528b2c61 | 154 | SQUIDCEXTERN char *storeSwapMetaPack(tlv * tlv_list, int *length); |
e1f7507e | 155 | /// \ingroup SwapStoreAPI |
528b2c61 | 156 | SQUIDCEXTERN tlv *storeSwapMetaBuild(StoreEntry * e); |
e1f7507e | 157 | /// \ingroup SwapStoreAPI |
528b2c61 | 158 | SQUIDCEXTERN void storeSwapTLVFree(tlv * n); |
159 | ||
160 | #endif /* SQUID_TYPELENGTHVALUE_H */ |