Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
Complex classes like tar often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use tar, and based on these observations, apply Extract Interface, too.
1 | <?php |
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91 | class tar |
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92 | { |
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93 | /** |
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94 | * *#@+ |
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95 | * Unprocessed Archive Information |
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96 | */ |
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97 | public $filename; |
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98 | public $isGzipped; |
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99 | public $tar_file; |
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100 | /** |
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101 | * *#@- |
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102 | */ |
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103 | |||
104 | /** |
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105 | * *#@+ |
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106 | * Processed Archive Information |
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107 | */ |
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108 | public $files; |
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109 | public $directories; |
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110 | public $numFiles; |
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111 | public $numDirectories; |
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112 | |||
113 | /** |
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114 | * *#@- |
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115 | */ |
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116 | |||
117 | /** |
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118 | * Computes the unsigned Checksum of a file's header |
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119 | * to try to ensure valid file |
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120 | * |
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121 | * @param string $bytestring |
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122 | * @return int|string |
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123 | * @access private |
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124 | */ |
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125 | private function __computeUnsignedChecksum($bytestring) |
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136 | } |
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137 | |||
138 | /** |
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139 | * Converts a NULL padded string to a non-NULL padded string |
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140 | * |
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141 | * @param string $string |
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142 | * @return string |
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143 | * @access private |
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144 | */ |
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145 | private function __parseNullPaddedString($string) |
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146 | { |
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147 | $position = strpos($string, chr(0)); |
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148 | return substr($string, 0, $position); |
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149 | } |
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150 | |||
151 | /** |
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152 | * This function parses the current TAR file |
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153 | * |
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154 | * @return bool always TRUE |
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155 | * @access private |
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156 | */ |
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157 | private function __parseTar() |
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158 | { |
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159 | // Read Files from archive |
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160 | $tar_length = strlen($this->tar_file); |
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161 | $main_offset = 0; |
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162 | $this->numFiles = 0; |
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163 | while ($main_offset < $tar_length) { |
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164 | // If we read a block of 512 nulls, we are at the end of the archive |
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165 | if (substr($this->tar_file, $main_offset, 512) == str_repeat(chr(0), 512)) { |
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166 | break; |
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167 | } |
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168 | // Parse file name |
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169 | $file_name = $this->__parseNullPaddedString(substr($this->tar_file, $main_offset, 100)); |
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170 | // Parse the file mode |
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171 | $file_mode = substr($this->tar_file, $main_offset + 100, 8); |
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172 | // Parse the file user ID |
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173 | $file_uid = octdec(substr($this->tar_file, $main_offset + 108, 8)); |
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174 | // Parse the file group ID |
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175 | $file_gid = octdec(substr($this->tar_file, $main_offset + 116, 8)); |
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176 | // Parse the file size |
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177 | $file_size = octdec(substr($this->tar_file, $main_offset + 124, 12)); |
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178 | // Parse the file update time - unix timestamp format |
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179 | $file_time = octdec(substr($this->tar_file, $main_offset + 136, 12)); |
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180 | // Parse Checksum |
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181 | $file_chksum = octdec(substr($this->tar_file, $main_offset + 148, 6)); |
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182 | // Parse user name |
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183 | $file_uname = $this->__parseNullPaddedString(substr($this->tar_file, $main_offset + 265, 32)); |
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184 | // Parse Group name |
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185 | $file_gname = $this->__parseNullPaddedString(substr($this->tar_file, $main_offset + 297, 32)); |
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186 | // Make sure our file is valid |
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187 | if ($this->__computeUnsignedChecksum(substr($this->tar_file, $main_offset, 512)) != $file_chksum) { |
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188 | return false; |
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189 | } |
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190 | // Parse File Contents |
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191 | $file_contents = substr($this->tar_file, $main_offset + 512, $file_size); |
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192 | |||
193 | /** |
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194 | * ### Unused Header Information ### |
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195 | * $activeFile["typeflag"] = substr($this->tar_file,$main_offset + 156,1); |
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196 | * $activeFile["linkname"] = substr($this->tar_file,$main_offset + 157,100); |
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197 | * $activeFile["magic"] = substr($this->tar_file,$main_offset + 257,6); |
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198 | * $activeFile["version"] = substr($this->tar_file,$main_offset + 263,2); |
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199 | * $activeFile["devmajor"] = substr($this->tar_file,$main_offset + 329,8); |
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200 | * $activeFile["devminor"] = substr($this->tar_file,$main_offset + 337,8); |
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201 | * $activeFile["prefix"] = substr($this->tar_file,$main_offset + 345,155); |
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202 | * $activeFile["endheader"] = substr($this->tar_file,$main_offset + 500,12); |
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203 | */ |
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204 | |||
205 | if ($file_size > 0) { |
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206 | // Increment number of files |
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207 | $this->numFiles++; |
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208 | // Create us a new file in our array |
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209 | $activeFile =& $this->files[]; |
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210 | // Asign Values |
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211 | $activeFile["name"] = $file_name; |
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212 | $activeFile["mode"] = $file_mode; |
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213 | $activeFile["size"] = $file_size; |
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214 | $activeFile["time"] = $file_time; |
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215 | $activeFile["user_id"] = $file_uid; |
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216 | $activeFile["group_id"] = $file_gid; |
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217 | $activeFile["user_name"] = $file_uname; |
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218 | $activeFile["group_name"] = $file_gname; |
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219 | $activeFile["checksum"] = $file_chksum; |
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220 | $activeFile["file"] = $file_contents; |
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221 | } else { |
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222 | // Increment number of directories |
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223 | $this->numDirectories++; |
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224 | // Create a new directory in our array |
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225 | $activeDir =& $this->directories[]; |
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226 | // Assign values |
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227 | $activeDir["name"] = $file_name; |
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228 | $activeDir["mode"] = $file_mode; |
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229 | $activeDir["time"] = $file_time; |
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230 | $activeDir["user_id"] = $file_uid; |
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231 | $activeDir["group_id"] = $file_gid; |
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232 | $activeDir["user_name"] = $file_uname; |
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233 | $activeDir["group_name"] = $file_gname; |
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234 | $activeDir["checksum"] = $file_chksum; |
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235 | } |
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236 | // Move our offset the number of blocks we have processed |
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237 | $main_offset += 512 + (ceil($file_size / 512) * 512); |
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238 | } |
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239 | |||
240 | return true; |
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241 | } |
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242 | |||
243 | /** |
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244 | * Read a non gzipped tar file in for processing. |
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245 | * |
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246 | * @param string $filename full filename |
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247 | * @return bool always TRUE |
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248 | * @access private |
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249 | */ |
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250 | private function __readTar($filename = '') |
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251 | { |
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252 | // Set the filename to load |
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253 | if (!$filename) { |
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254 | $filename = $this->filename; |
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255 | } |
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256 | // Read in the TAR file |
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257 | $fp = fopen($filename, 'rb'); |
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258 | $this->tar_file = fread($fp, filesize($filename)); |
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259 | fclose($fp); |
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260 | |||
261 | if ($this->tar_file[0] == chr(31) && $this->tar_file[1] == chr(139) && $this->tar_file[2] == chr(8)) { |
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262 | if (!function_exists('gzinflate')) { |
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263 | return false; |
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264 | } |
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265 | $this->isGzipped = true; |
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266 | $this->tar_file = gzinflate(substr($this->tar_file, 10, -4)); |
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267 | } |
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268 | // Parse the TAR file |
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269 | $this->__parseTar(); |
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270 | |||
271 | return true; |
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272 | } |
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273 | |||
274 | /** |
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275 | * Generates a TAR file from the processed data |
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276 | * |
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277 | * @return bool always TRUE |
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278 | * @access private |
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279 | */ |
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280 | private function __generateTar() |
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281 | { |
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282 | // Clear any data currently in $this->tar_file |
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283 | unset($this->tar_file); |
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284 | // Generate Records for each directory, if we have directories |
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285 | if ($this->numDirectories > 0) { |
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286 | foreach ($this->directories as $key => $information) { |
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287 | $header = ''; |
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288 | // Generate tar header for this directory |
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289 | // Filename, Permissions, UID, GID, size, Time, checksum, typeflag, linkname, magic, version, user name, group name, devmajor, devminor, prefix, end |
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290 | $header .= str_pad($information["name"], 100, chr(0)); |
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291 | $header .= str_pad(decoct($information["mode"]), 7, "0", STR_PAD_LEFT) . chr(0); |
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292 | $header .= str_pad(decoct($information["user_id"]), 7, "0", STR_PAD_LEFT) . chr(0); |
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293 | $header .= str_pad(decoct($information["group_id"]), 7, "0", STR_PAD_LEFT) . chr(0); |
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294 | $header .= str_pad(decoct(0), 11, "0", STR_PAD_LEFT) . chr(0); |
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295 | $header .= str_pad(decoct($information["time"]), 11, "0", STR_PAD_LEFT) . chr(0); |
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296 | $header .= str_repeat(" ", 8); |
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297 | $header .= "5"; |
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298 | $header .= str_repeat(chr(0), 100); |
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299 | $header .= str_pad("ustar", 6, chr(32)); |
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300 | $header .= chr(32) . chr(0); |
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301 | $header .= str_pad("", 32, chr(0)); |
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302 | $header .= str_pad("", 32, chr(0)); |
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303 | $header .= str_repeat(chr(0), 8); |
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304 | $header .= str_repeat(chr(0), 8); |
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305 | $header .= str_repeat(chr(0), 155); |
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306 | $header .= str_repeat(chr(0), 12); |
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307 | // Compute header checksum |
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308 | $checksum = str_pad(decoct($this->__computeUnsignedChecksum($header)), 6, "0", STR_PAD_LEFT); |
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309 | for ($i = 0; $i < 6; ++$i) { |
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310 | $header[(148 + $i)] = substr($checksum, $i, 1); |
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311 | } |
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312 | $header[154] = chr(0); |
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313 | $header[155] = chr(32); |
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314 | // Add new tar formatted data to tar file contents |
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315 | $this->tar_file .= $header; |
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316 | } |
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317 | } |
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318 | // Generate Records for each file, if we have files (We should...) |
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319 | if ($this->numFiles > 0) { |
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320 | $this->tar_file = ''; |
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321 | foreach ($this->files as $key => $information) { |
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322 | $header = ''; |
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323 | // Generate the TAR header for this file |
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324 | // Filename, Permissions, UID, GID, size, Time, checksum, typeflag, linkname, magic, version, user name, group name, devmajor, devminor, prefix, end |
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325 | $header .= str_pad($information["name"], 100, chr(0)); |
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326 | $header .= str_pad(decoct($information["mode"]), 7, "0", STR_PAD_LEFT) . chr(0); |
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327 | $header .= str_pad(decoct($information["user_id"]), 7, "0", STR_PAD_LEFT) . chr(0); |
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328 | $header .= str_pad(decoct($information["group_id"]), 7, "0", STR_PAD_LEFT) . chr(0); |
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329 | $header .= str_pad(decoct($information["size"]), 11, "0", STR_PAD_LEFT) . chr(0); |
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330 | $header .= str_pad(decoct($information["time"]), 11, "0", STR_PAD_LEFT) . chr(0); |
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331 | $header .= str_repeat(" ", 8); |
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332 | $header .= "0"; |
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333 | $header .= str_repeat(chr(0), 100); |
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334 | $header .= str_pad("ustar", 6, chr(32)); |
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335 | $header .= chr(32) . chr(0); |
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336 | $header .= str_pad($information["user_name"], 32, chr(0)); // How do I get a file's user name from PHP? |
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337 | $header .= str_pad($information["group_name"], 32, chr(0)); // How do I get a file's group name from PHP? |
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338 | $header .= str_repeat(chr(0), 8); |
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339 | $header .= str_repeat(chr(0), 8); |
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340 | $header .= str_repeat(chr(0), 155); |
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341 | $header .= str_repeat(chr(0), 12); |
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342 | // Compute header checksum |
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343 | $checksum = str_pad(decoct($this->__computeUnsignedChecksum($header)), 6, "0", STR_PAD_LEFT); |
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344 | for ($i = 0; $i < 6; ++$i) { |
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345 | $header[(148 + $i)] = substr($checksum, $i, 1); |
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346 | } |
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347 | $header[154] = chr(0); |
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348 | $header[155] = chr(32); |
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349 | // Pad file contents to byte count divisible by 512 |
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350 | $file_contents = str_pad($information["file"], (ceil($information["size"] / 512) * 512), chr(0)); |
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351 | // Add new tar formatted data to tar file contents |
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352 | $this->tar_file .= $header . $file_contents; |
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353 | } |
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354 | } |
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355 | // Add 512 bytes of NULLs to designate EOF |
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356 | $this->tar_file .= str_repeat(chr(0), 512); |
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357 | return true; |
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358 | } |
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359 | |||
360 | /** |
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361 | * Open a TAR file |
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362 | * |
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363 | * @param string $filename |
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364 | * @return bool |
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365 | */ |
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366 | public function openTAR($filename) |
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367 | { |
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368 | // Clear any values from previous tar archives |
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369 | unset($this->filename); |
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370 | unset($this->isGzipped); |
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371 | unset($this->tar_file); |
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372 | unset($this->files); |
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373 | unset($this->directories); |
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374 | unset($this->numFiles); |
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375 | unset($this->numDirectories); |
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376 | // If the tar file doesn't exist... |
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377 | if (!XoopsLoad::fileExists($filename)) { |
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378 | return false; |
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379 | } |
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380 | |||
381 | $this->filename = $filename; |
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382 | // Parse this file |
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383 | $this->__readTar(); |
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384 | return true; |
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385 | } |
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386 | |||
387 | /** |
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388 | * Appends a tar file to the end of the currently opened tar file. |
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389 | * |
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390 | * @param string $filename |
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391 | * @return bool |
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392 | */ |
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393 | public function appendTar($filename) |
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394 | { |
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395 | // If the tar file doesn't exist... |
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396 | if (!XoopsLoad::fileExists($filename)) { |
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397 | return false; |
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398 | } |
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399 | $this->__readTar($filename); |
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400 | return true; |
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401 | } |
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402 | |||
403 | /** |
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404 | * Retrieves information about a file in the current tar archive |
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405 | * |
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406 | * @param string $filename |
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407 | * @return string FALSE on fail |
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408 | */ |
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409 | public function getFile($filename) |
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419 | } |
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420 | |||
421 | /** |
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422 | * Retrieves information about a directory in the current tar archive |
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423 | * |
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424 | * @param string $dirname |
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425 | * @return string FALSE on fail |
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426 | */ |
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427 | public function getDirectory($dirname) |
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437 | } |
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438 | |||
439 | /** |
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440 | * Check if this tar archive contains a specific file |
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441 | * |
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442 | * @param string $filename |
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443 | * @return bool |
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444 | */ |
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445 | public function containsFile($filename) |
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446 | { |
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447 | if ($this->numFiles > 0) { |
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448 | foreach ($this->files as $information) { |
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449 | if ($information['name'] == $filename) { |
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450 | return true; |
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451 | } |
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452 | } |
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453 | } |
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454 | return false; |
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455 | } |
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456 | |||
457 | /** |
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458 | * Check if this tar archive contains a specific directory |
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459 | * |
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460 | * @param string $dirname |
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461 | * @return bool |
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462 | */ |
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463 | public function containsDirectory($dirname) |
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464 | { |
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465 | if ($this->numDirectories > 0) { |
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466 | foreach ($this->directories as $information) { |
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467 | if ($information['name'] == $dirname) { |
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468 | return true; |
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469 | } |
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470 | } |
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471 | } |
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472 | return false; |
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473 | } |
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474 | |||
475 | /** |
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476 | * Add a directory to this tar archive |
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477 | * |
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478 | * @param string $dirname |
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479 | * @return bool |
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480 | */ |
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481 | public function addDirectory($dirname) |
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482 | { |
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483 | if (!XoopsLoad::fileExists($dirname)) { |
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484 | return false; |
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485 | } |
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486 | // Get directory information |
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487 | $file_information = stat($dirname); |
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488 | // Add directory to processed data |
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489 | $this->numDirectories++; |
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490 | $activeDir =& $this->directories[]; |
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491 | $activeDir['name'] = $dirname; |
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492 | $activeDir['mode'] = $file_information['mode']; |
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493 | $activeDir['time'] = $file_information['time']; |
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494 | $activeDir['user_id'] = $file_information['uid']; |
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495 | $activeDir['group_id'] = $file_information['gid']; |
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496 | $activeDir['checksum'] = isset($checksum) ? $checksum : ''; |
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497 | |||
498 | return true; |
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499 | } |
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500 | |||
501 | /** |
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502 | * Add a file to the tar archive |
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503 | * |
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504 | * @param string $filename |
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505 | * @param boolean $binary Binary file? |
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506 | * @return bool |
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507 | */ |
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508 | public function addFile($filename, $binary = false) |
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509 | { |
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510 | // Make sure the file we are adding exists! |
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511 | if (!XoopsLoad::fileExists($filename)) { |
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512 | return false; |
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513 | } |
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514 | // Make sure there are no other files in the archive that have this same filename |
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515 | if ($this->containsFile($filename)) { |
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516 | return false; |
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517 | } |
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518 | // Get file information |
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519 | $file_information = stat($filename); |
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520 | // Read in the file's contents |
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521 | if (!$binary) { |
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522 | $fp = fopen($filename, 'r'); |
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523 | } else { |
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524 | $fp = fopen($filename, 'rb'); |
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525 | } |
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526 | $file_contents = fread($fp, filesize($filename)); |
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527 | fclose($fp); |
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528 | // Add file to processed data |
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529 | $this->numFiles++; |
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530 | $activeFile =& $this->files[]; |
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531 | $activeFile['name'] = $filename; |
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532 | $activeFile['mode'] = $file_information['mode']; |
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533 | $activeFile['user_id'] = $file_information['uid']; |
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534 | $activeFile['group_id'] = $file_information['gid']; |
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535 | $activeFile['size'] = $file_information['size']; |
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536 | $activeFile['time'] = $file_information['mtime']; |
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537 | $activeFile['checksum'] = isset($checksum) ? $checksum : ''; |
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538 | $activeFile['user_name'] = ''; |
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539 | $activeFile['group_name'] = ''; |
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540 | $activeFile['file'] = trim($file_contents); |
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541 | return true; |
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542 | } |
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543 | |||
544 | /** |
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545 | * Remove a file from the tar archive |
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546 | * |
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547 | * @param string $filename |
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548 | * @return bool |
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549 | */ |
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550 | public function removeFile($filename) |
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551 | { |
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552 | if ($this->numFiles > 0) { |
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553 | foreach ($this->files as $key => $information) { |
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554 | if ($information['name'] == $filename) { |
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555 | $this->numFiles--; |
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556 | unset($this->files[$key]); |
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557 | return true; |
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558 | } |
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559 | } |
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560 | } |
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561 | return false; |
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562 | } |
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563 | |||
564 | /** |
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565 | * Remove a directory from the tar archive |
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566 | * |
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567 | * @param string $dirname |
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568 | * @return bool |
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569 | */ |
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570 | public function removeDirectory($dirname) |
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582 | } |
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583 | |||
584 | /** |
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585 | * Write the currently loaded tar archive to disk |
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586 | * |
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587 | * @return bool |
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588 | */ |
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589 | public function saveTar() |
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597 | } |
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598 | |||
599 | /** |
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600 | * Saves tar archive to a different file than the current file |
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601 | * |
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602 | * @param string $filename |
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603 | * @param bool $useGzip Use GZ compression? |
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604 | * @return bool |
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605 | */ |
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606 | public function toTar($filename, $useGzip) |
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628 | } |
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629 | |||
630 | /** |
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631 | * Sends tar archive to stdout |
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632 | * |
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633 | * @param string $filename |
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634 | * @param bool $useGzip Use GZ compression? |
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635 | * @return string |
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636 | */ |
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637 | public function toTarOutput($filename, $useGzip) |
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655 | } |
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656 | } |
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657 |