1 | |
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2 | /* |
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3 | Copyright 2013 Willem Vermin, SURFsara |
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4 | |
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5 | Licensed under the Apache License, Version 2.0 (the "License"); |
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6 | you may not use this file except in compliance with the License. |
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7 | You may obtain a copy of the License at |
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8 | |
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9 | http://www.apache.org/licenses/LICENSE-2.0 |
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10 | |
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11 | Unless required by applicable law or agreed to in writing, software |
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12 | distributed under the License is distributed on an "AS IS" BASIS, |
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13 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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14 | See the License for the specific language governing permissions and |
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15 | limitations under the License. |
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16 | */ |
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17 | #include "stopos_pool.h" |
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18 | #include "flatfile_pool.h" |
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19 | #include <sys/types.h> |
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20 | #include <sys/stat.h> |
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21 | #include <errno.h> |
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22 | #include <fcntl.h> |
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23 | #include <stdlib.h> |
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24 | #include "wutils.h" |
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25 | #include <string.h> |
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26 | #include <strings.h> |
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27 | #include <stdio.h> |
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28 | #include <algorithm> |
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29 | #include "stopos.h" |
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30 | |
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31 | // |
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32 | // this->status.extra is always pointing to |
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33 | // the first free slot |
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34 | // |
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35 | // records are stored thusly: |
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36 | // character to denote if this record exists or is deleted |
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37 | // dbsep |
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38 | // |
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39 | // for a not deleted record, next fields: |
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40 | // key for this record |
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41 | // dbsep |
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42 | // 1st parameter of put_record |
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43 | // |
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44 | // for a deleted record: |
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45 | // pointer to next deleted record |
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46 | // |
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47 | |
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48 | // constructor |
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49 | flatfile_pool::flatfile_pool() |
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50 | { |
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51 | this->whoami = "flat"; |
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52 | this->statuskey.set_slot(this->statuskey.get_key()); |
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53 | } |
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54 | |
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55 | std::string flatfile_pool::key_to_slot(const std::string &k) |
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56 | { |
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57 | |
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58 | if (strtoslot(this->status.extra) == 0) |
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59 | return k; |
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60 | |
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61 | std::string slot = this->status.extra; |
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62 | std::string r; |
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63 | off_t p = strtoslot(slot)*this->reclen; |
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64 | this->read_string(r, p); |
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65 | this->status.extra = r.substr(2); |
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66 | |
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67 | return slot; |
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68 | } |
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69 | |
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70 | off_t flatfile_pool::strtoslot(const std::string &s) |
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71 | { |
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72 | return stopos_key::KeyToNumber(s); |
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73 | } |
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74 | |
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75 | std::string flatfile_pool::slottostr(off_t l) |
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76 | { |
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77 | return stopos_key::NumberToKey(l); |
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78 | } |
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79 | |
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80 | int flatfile_pool::haskey(std::string &r, const std::string &k) |
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81 | { |
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82 | size_t q1 = 1; |
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83 | // find second separator. The first one is on postion 1 |
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84 | size_t q2 = r.find(dbsep,2); |
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85 | |
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86 | std::string key = r.substr(q1+1,q2-q1-1); |
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87 | if (key != k) |
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88 | return this->NOTFOUND; |
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89 | r.erase(0,q2+1); |
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90 | return 0; |
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91 | } |
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92 | |
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93 | int flatfile_pool::get_record(std::string &r, const std::string &k, const std::string &l) |
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94 | { |
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95 | int rc; |
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96 | |
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97 | off_t p = this->strtoslot(l)*reclen; |
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98 | |
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99 | rc = this->read_string(r,p); |
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100 | if (rc !=0 ) |
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101 | return rc; |
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102 | |
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103 | if (r[0] == this->deleted) |
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104 | return this->NOTFOUND; |
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105 | |
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106 | // this record was not deleted, but it could be that |
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107 | // the key does not match |
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108 | // |
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109 | |
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110 | rc = this->haskey(r,k); |
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111 | if (rc != 0) |
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112 | return rc; |
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113 | |
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114 | return 0; |
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115 | } |
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116 | |
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117 | int flatfile_pool::put_record(const std::string &r, |
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118 | const std::string &k, |
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119 | const std::string &l) |
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120 | { |
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121 | std::string buf; |
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122 | |
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123 | buf = buf + this->exists + dbsep + k + dbsep + r; |
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124 | |
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125 | if (buf.size() >= this->reclen) // >= because we need place for |
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126 | // end-of-string zero |
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127 | return RECORDTOOLONG; |
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128 | |
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129 | off_t p = this->strtoslot(l)*reclen; |
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130 | |
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131 | return this->write_string(buf,p); |
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132 | } |
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133 | |
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134 | int flatfile_pool::remove_record(const std::string &k, const std::string &l) |
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135 | { |
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136 | int rc; |
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137 | |
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138 | off_t p = this->strtoslot(l)*reclen; |
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139 | |
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140 | std::string r; |
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141 | rc = this->read_string(r,p); |
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142 | if (rc != 0) |
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143 | return rc; |
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144 | |
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145 | rc = haskey(r,k); |
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146 | if (rc != 0) |
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147 | return rc; |
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148 | |
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149 | r = this->deleted; |
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150 | |
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151 | if (status.extra == slottostr(0)) |
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152 | r = r + dbsep + slottostr(0); |
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153 | else |
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154 | r = r + dbsep + status.extra; |
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155 | status.extra = l; |
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156 | |
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157 | return this->write_string(r,p); |
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158 | } |
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159 | |
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160 | int flatfile_pool::read_string(std::string &r, off_t p) |
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161 | { |
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162 | |
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163 | char b[this->reclen]; |
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164 | off_t rc; |
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165 | rc = lseek(this->ff, p, SEEK_SET); |
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166 | if (rc == -1) |
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167 | return FETCHERROR; |
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168 | |
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169 | ssize_t rc1; |
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170 | rc1 = read(this->ff, b, this->reclen); |
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171 | if (rc1 != this->reclen) |
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172 | return FETCHERROR; |
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173 | |
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174 | r = b; |
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175 | |
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176 | return 0; |
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177 | } |
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178 | |
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179 | |
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180 | int flatfile_pool::write_string(const std::string &r, off_t p) |
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181 | { |
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182 | int rc; |
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183 | char b[this->reclen]; |
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184 | |
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185 | rc = lseek(this->ff,p,SEEK_SET); |
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186 | if (rc == -1) |
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187 | return STOREERROR; |
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188 | |
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189 | bzero(b, this->reclen); |
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190 | strncpy(b,r.c_str(),r.size()); |
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191 | ssize_t first = 0; |
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192 | ssize_t togo = this->reclen; |
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193 | ssize_t written; |
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194 | |
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195 | do |
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196 | { |
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197 | written = write(ff,&b[first],togo); |
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198 | if (written == -1) |
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199 | { |
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200 | perror("write:"); |
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201 | return 2; |
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202 | } |
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203 | togo -= written; |
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204 | first += written; |
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205 | } while(togo !=0); |
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206 | |
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207 | return 0; |
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208 | } |
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209 | |
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210 | |
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211 | int flatfile_pool::create_db(const std::string &dbname) |
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212 | { |
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213 | int rc; |
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214 | |
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215 | rc = this->purge_db(); |
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216 | if (rc != 0) |
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217 | return rc; |
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218 | |
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219 | // The db_name can be composed of parts separated with '/' |
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220 | // we try to create this path until the last '/' |
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221 | |
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222 | size_t p = dbname.find_last_of('/'); |
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223 | rc = mkdir_p(dbname.substr(0,p+1),0755); |
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224 | if (rc != 0) |
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225 | return CREATEERROR; |
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226 | |
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227 | rc = this->open_db(O_CREAT|O_RDWR); |
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228 | if (rc != 0) |
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229 | return rc; |
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230 | this->close_db(); |
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231 | |
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232 | this->status.extra = stopos_key::NumberToKey(0); |
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233 | |
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234 | return 0; |
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235 | } |
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236 | |
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237 | int flatfile_pool::purge_db(void) |
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238 | { |
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239 | if (this->db_name == 0) |
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240 | return NOFILENAME; |
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241 | |
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242 | this->close_db(); |
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243 | |
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244 | unlink(this->db_name); |
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245 | return 0; |
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246 | } |
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247 | |
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248 | int flatfile_pool::open_db() |
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249 | { |
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250 | int rc; |
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251 | rc = this->open_db(O_RDWR); |
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252 | return rc; |
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253 | } |
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254 | |
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255 | int flatfile_pool::open_db(int flags) |
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256 | { |
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257 | int rc; |
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258 | |
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259 | if (this->db_name == 0) |
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260 | return NOFILENAME; |
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261 | |
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262 | if (this->db_open) |
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263 | return 0; |
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264 | |
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265 | this->ff = open(this->db_name, flags,0644); |
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266 | if (this->ff < 0) |
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267 | return OPENERROR; |
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268 | |
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269 | struct flock lock; |
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270 | lock.l_type = F_RDLCK|F_WRLCK; |
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271 | lock.l_whence = SEEK_SET; |
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272 | lock.l_start = 0; |
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273 | lock.l_len = 0; |
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274 | |
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275 | rc = fcntl(this->ff,F_SETLKW,&lock); |
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276 | if (rc < 0) |
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277 | return LOCKERROR; |
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278 | |
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279 | this->db_open = 1; |
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280 | |
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281 | return 0; |
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282 | } |
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283 | |
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284 | int flatfile_pool::close_db(void) |
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285 | { |
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286 | if (!this->db_open) |
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287 | return 0; |
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288 | |
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289 | int rc; |
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290 | |
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291 | struct flock lock; |
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292 | lock.l_type = F_UNLCK; |
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293 | lock.l_whence = SEEK_SET; |
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294 | lock.l_start = 0; |
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295 | lock.l_len = 0; |
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296 | |
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297 | rc = fcntl(this->ff,F_SETLKW,&lock); |
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298 | if (rc < 0) |
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299 | return UNLOCKERROR; |
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300 | |
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301 | rc = close(this->ff); |
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302 | if (rc == -1) |
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303 | return CLOSEERROR; |
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304 | |
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305 | this->db_open = 0; |
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306 | |
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307 | return 0; |
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308 | } |
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309 | |
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