00001 /** @file 00002 00003 Backwards compatibility support for the cache. 00004 00005 @section license License 00006 00007 Licensed to the Apache Software Foundation (ASF) under one 00008 or more contributor license agreements. See the NOTICE file 00009 distributed with this work for additional information 00010 regarding copyright ownership. The ASF licenses this file 00011 to you under the Apache License, Version 2.0 (the 00012 "License"); you may not use this file except in compliance 00013 with the License. You may obtain a copy of the License at 00014 00015 http://www.apache.org/licenses/LICENSE-2.0 00016 00017 Unless required by applicable law or agreed to in writing, software 00018 distributed under the License is distributed on an "AS IS" BASIS, 00019 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 00020 See the License for the specific language governing permissions and 00021 limitations under the License. 00022 */ 00023 00024 00025 #ifndef _P_CACHE_BC_H__ 00026 #define _P_CACHE_BC_H__ 00027 00028 namespace cache_bc { 00029 00030 /* This looks kind of dumb, but I think it's useful. We import external structure 00031 dependencies in to this namespace so we can at least (1) notice them and 00032 (2) change them if the current structure changes. 00033 */ 00034 00035 typedef HTTPHdr HTTPHdr_v21; 00036 typedef HdrHeap HdrHeap_v23; 00037 typedef CryptoHash CryptoHash_v23; 00038 typedef HTTPCacheAlt HTTPCacheAlt_v23; 00039 00040 /** Cache backwards compatibility structure - the fragment table. 00041 This is copied from @c HTTPCacheAlt in @c HTTP.h. 00042 */ 00043 struct HTTPCacheFragmentTable { 00044 /// # of fragment offsets in this alternate. 00045 /// @note This is one less than the number of fragments. 00046 int m_frag_offset_count; 00047 /// Type of offset for a fragment. 00048 typedef uint64_t FragOffset; 00049 /// Table of fragment offsets. 00050 /// @note The offsets are forward looking so that frag[0] is the 00051 /// first byte past the end of fragment 0 which is also the first 00052 /// byte of fragment 1. For this reason there is no fragment offset 00053 /// for the last fragment. 00054 FragOffset *m_frag_offsets; 00055 /// # of fragment offsets built in to object. 00056 static int const N_INTEGRAL_FRAG_OFFSETS = 4; 00057 /// Integral fragment offset table. 00058 FragOffset m_integral_frag_offsets[N_INTEGRAL_FRAG_OFFSETS]; 00059 }; 00060 00061 // From before moving the fragment table to the alternate. 00062 struct HTTPCacheAlt_v21 00063 { 00064 uint32_t m_magic; 00065 00066 int32_t m_writeable; 00067 int32_t m_unmarshal_len; 00068 00069 int32_t m_id; 00070 int32_t m_rid; 00071 00072 int32_t m_object_key[4]; 00073 int32_t m_object_size[2]; 00074 00075 HTTPHdr_v21 m_request_hdr; 00076 HTTPHdr_v21 m_response_hdr; 00077 00078 time_t m_request_sent_time; 00079 time_t m_response_received_time; 00080 00081 RefCountObj *m_ext_buffer; 00082 00083 // The following methods were added for BC support. 00084 // Checks itself to verify that it is unmarshalled and v21 format. 00085 bool is_unmarshalled_format() const { 00086 return CACHE_ALT_MAGIC_MARSHALED == m_magic && reinterpret_cast<intptr_t>(m_request_hdr.m_heap) == sizeof(*this); 00087 } 00088 }; 00089 00090 /// Really just a namespace, doesn't depend on any of the members. 00091 struct HTTPInfo_v21 { 00092 typedef uint64_t FragOffset; 00093 /// Version upgrade methods 00094 /// @a src , @a dst , and @a n are updated upon return. 00095 /// @a n is the space in @a dst remaining. 00096 /// @return @c false if something went wrong. 00097 static bool copy_and_upgrade_unmarshalled_to_v23(char*& dst, char*& src, size_t& length, int n_frags, FragOffset* frag_offsets); 00098 /// The size of the marshalled data of a marshalled alternate header. 00099 static size_t marshalled_length(void* data); 00100 }; 00101 00102 /// Pre version 24. 00103 struct Doc_v23 00104 { 00105 uint32_t magic; // DOC_MAGIC 00106 uint32_t len; // length of this segment (including hlen, flen & sizeof(Doc), unrounded) 00107 uint64_t total_len; // total length of document 00108 CryptoHash_v23 first_key; ///< first key in object. 00109 CryptoHash_v23 key; ///< Key for this doc. 00110 uint32_t hlen; ///< Length of this header. 00111 uint32_t doc_type:8; ///< Doc type - indicates the format of this structure and its content. 00112 uint32_t _flen:24; ///< Fragment table length. 00113 uint32_t sync_serial; 00114 uint32_t write_serial; 00115 uint32_t pinned; // pinned until 00116 uint32_t checksum; 00117 00118 char* hdr(); 00119 char* data(); 00120 size_t data_len(); 00121 }; 00122 00123 static size_t const sizeofDoc_v23 = sizeof(Doc_v23); 00124 char* Doc_v23::data() { return reinterpret_cast<char*>(this) + sizeofDoc_v23 + _flen + hlen; } 00125 size_t Doc_v23::data_len() { return len - sizeofDoc_v23 - hlen; } 00126 char* Doc_v23::hdr() { return reinterpret_cast<char*>(this) + sizeofDoc_v23; } 00127 00128 00129 } // namespace cache_bc 00130 00131 #endif /* _P_CACHE_BC_H__ */
1.7.1