| 1 | // -*- mode: cpp; mode: fold -*- |
| 2 | // Description /*{{{*/ |
| 3 | // $Id: acquire-worker.h,v 1.12 2001/02/20 07:03:17 jgg Exp $ |
| 4 | /* ###################################################################### |
| 5 | |
| 6 | Acquire Worker - Worker process manager |
| 7 | |
| 8 | Each worker class is associated with exaclty one subprocess. |
| 9 | |
| 10 | ##################################################################### */ |
| 11 | /*}}}*/ |
| 12 | |
| 13 | /** \addtogroup acquire |
| 14 | * @{ |
| 15 | * |
| 16 | * \file acquire-worker.h |
| 17 | */ |
| 18 | |
| 19 | #ifndef PKGLIB_ACQUIRE_WORKER_H |
| 20 | #define PKGLIB_ACQUIRE_WORKER_H |
| 21 | |
| 22 | #include <apt-pkg/acquire.h> |
| 23 | #include <apt-pkg/weakptr.h> |
| 24 | |
| 25 | |
| 26 | /** \brief A fetch subprocess. |
| 27 | * |
| 28 | * A worker process is responsible for one stage of the fetch. This |
| 29 | * class encapsulates the communications protocol between the master |
| 30 | * process and the worker, from the master end. |
| 31 | * |
| 32 | * Each worker is intrinsically placed on two linked lists. The |
| 33 | * Queue list (maintained in the #NextQueue variable) is maintained |
| 34 | * by the pkgAcquire::Queue class; it represents the set of workers |
| 35 | * assigned to a particular queue. The Acquire list (maintained in |
| 36 | * the #NextAcquire variable) is maintained by the pkgAcquire class; |
| 37 | * it represents the set of active workers for a particular |
| 38 | * pkgAcquire object. |
| 39 | * |
| 40 | * \todo Like everything else in the Acquire system, this has way too |
| 41 | * many protected items. |
| 42 | * |
| 43 | * \sa pkgAcqMethod, pkgAcquire::Item, pkgAcquire |
| 44 | */ |
| 45 | class pkgAcquire::Worker : public WeakPointable |
| 46 | { |
| 47 | /** \brief dpointer placeholder (for later in case we need it) */ |
| 48 | void *d; |
| 49 | |
| 50 | friend class pkgAcquire; |
| 51 | |
| 52 | protected: |
| 53 | friend class Queue; |
| 54 | |
| 55 | /** \brief The next link on the Queue list. |
| 56 | * |
| 57 | * \todo This is always NULL; is it just for future use? |
| 58 | */ |
| 59 | Worker *NextQueue; |
| 60 | |
| 61 | /** \brief The next link on the Acquire list. */ |
| 62 | Worker *NextAcquire; |
| 63 | |
| 64 | /** \brief The Queue with which this worker is associated. */ |
| 65 | Queue *OwnerQ; |
| 66 | |
| 67 | /** \brief The download progress indicator to which progress |
| 68 | * messages should be sent. |
| 69 | */ |
| 70 | pkgAcquireStatus *Log; |
| 71 | |
| 72 | /** \brief The configuration of this method. On startup, the |
| 73 | * target of this pointer is filled in with basic data about the |
| 74 | * method, as reported by the worker. |
| 75 | */ |
| 76 | MethodConfig *Config; |
| 77 | |
| 78 | /** \brief The access method to be used by this worker. |
| 79 | * |
| 80 | * \todo Doesn't this duplicate Config->Access? |
| 81 | */ |
| 82 | std::string Access; |
| 83 | |
| 84 | /** \brief The PID of the subprocess. */ |
| 85 | pid_t Process; |
| 86 | |
| 87 | /** \brief A file descriptor connected to the standard output of |
| 88 | * the subprocess. |
| 89 | * |
| 90 | * Used to read messages and data from the subprocess. |
| 91 | */ |
| 92 | int InFd; |
| 93 | |
| 94 | /** \brief A file descriptor connected to the standard input of the |
| 95 | * subprocess. |
| 96 | * |
| 97 | * Used to send commands and configuration data to the subprocess. |
| 98 | */ |
| 99 | int OutFd; |
| 100 | |
| 101 | /** \brief Set to \b true if the worker is in a state in which it |
| 102 | * might generate data or command responses. |
| 103 | * |
| 104 | * \todo Is this right? It's a guess. |
| 105 | */ |
| 106 | bool InReady; |
| 107 | |
| 108 | /** \brief Set to \b true if the worker is in a state in which it |
| 109 | * is legal to send commands to it. |
| 110 | * |
| 111 | * \todo Is this right? |
| 112 | */ |
| 113 | bool OutReady; |
| 114 | |
| 115 | /** If \b true, debugging output will be sent to std::clog. */ |
| 116 | bool Debug; |
| 117 | |
| 118 | /** \brief The raw text values of messages received from the |
| 119 | * worker, in sequence. |
| 120 | */ |
| 121 | std::vector<std::string> MessageQueue; |
| 122 | |
| 123 | /** \brief Buffers pending writes to the subprocess. |
| 124 | * |
| 125 | * \todo Wouldn't a std::dequeue be more appropriate? |
| 126 | */ |
| 127 | std::string OutQueue; |
| 128 | |
| 129 | /** \brief Common code for the constructor. |
| 130 | * |
| 131 | * Initializes NextQueue and NextAcquire to NULL; Process, InFd, |
| 132 | * and OutFd to -1, OutReady and InReady to \b false, and Debug |
| 133 | * from _config. |
| 134 | */ |
| 135 | void Construct(); |
| 136 | |
| 137 | /** \brief Retrieve any available messages from the subprocess. |
| 138 | * |
| 139 | * The messages are retrieved as in ::ReadMessages(), and |
| 140 | * MessageFailure() is invoked if an error occurs; in particular, |
| 141 | * if the pipe to the subprocess dies unexpectedly while a message |
| 142 | * is being read. |
| 143 | * |
| 144 | * \return \b true if the messages were successfully read, \b |
| 145 | * false otherwise. |
| 146 | */ |
| 147 | bool ReadMessages(); |
| 148 | |
| 149 | /** \brief Parse and dispatch pending messages. |
| 150 | * |
| 151 | * This dispatches the message in a manner appropriate for its |
| 152 | * type. |
| 153 | * |
| 154 | * \todo Several message types lack separate handlers. |
| 155 | * |
| 156 | * \sa Capabilities(), SendConfiguration(), MediaChange() |
| 157 | */ |
| 158 | bool RunMessages(); |
| 159 | |
| 160 | /** \brief Read and dispatch any pending messages from the |
| 161 | * subprocess. |
| 162 | * |
| 163 | * \return \b false if the subprocess died unexpectedly while a |
| 164 | * message was being transmitted. |
| 165 | */ |
| 166 | bool InFdReady(); |
| 167 | |
| 168 | /** \brief Send any pending commands to the subprocess. |
| 169 | * |
| 170 | * This method will fail if there is no pending output. |
| 171 | * |
| 172 | * \return \b true if all commands were succeeded, \b false if an |
| 173 | * error occurred (in which case MethodFailure() will be invoked). |
| 174 | */ |
| 175 | bool OutFdReady(); |
| 176 | |
| 177 | /** \brief Handle a 100 Capabilities response from the subprocess. |
| 178 | * |
| 179 | * \param Message the raw text of the message from the subprocess. |
| 180 | * |
| 181 | * The message will be parsed and its contents used to fill |
| 182 | * #Config. If #Config is NULL, this routine is a NOP. |
| 183 | * |
| 184 | * \return \b true. |
| 185 | */ |
| 186 | bool Capabilities(std::string Message); |
| 187 | |
| 188 | /** \brief Send a 601 Configuration message (containing the APT |
| 189 | * configuration) to the subprocess. |
| 190 | * |
| 191 | * The APT configuration will be send to the subprocess in a |
| 192 | * message of the following form: |
| 193 | * |
| 194 | * <pre> |
| 195 | * 601 Configuration |
| 196 | * Config-Item: Fully-Qualified-Item=Val |
| 197 | * Config-Item: Fully-Qualified-Item=Val |
| 198 | * ... |
| 199 | * </pre> |
| 200 | * |
| 201 | * \return \b true if the command was successfully sent, \b false |
| 202 | * otherwise. |
| 203 | */ |
| 204 | bool SendConfiguration(); |
| 205 | |
| 206 | /** \brief Handle a 403 Media Change message. |
| 207 | * |
| 208 | * \param Message the raw text of the message; the Media field |
| 209 | * indicates what type of media should be changed, and the Drive |
| 210 | * field indicates where the media is located. |
| 211 | * |
| 212 | * Invokes pkgAcquireStatus::MediaChange(Media, Drive) to ask the |
| 213 | * user to swap disks; informs the subprocess of the result (via |
| 214 | * 603 Media Changed, with the Failed field set to \b true if the |
| 215 | * user cancelled the media change). |
| 216 | */ |
| 217 | bool MediaChange(std::string Message); |
| 218 | |
| 219 | /** \brief Invoked when the worked process dies unexpectedly. |
| 220 | * |
| 221 | * Waits for the subprocess to terminate and generates an error if |
| 222 | * it terminated abnormally, then closes and blanks out all file |
| 223 | * descriptors. Discards all pending messages from the |
| 224 | * subprocess. |
| 225 | * |
| 226 | * \return \b false. |
| 227 | */ |
| 228 | bool MethodFailure(); |
| 229 | |
| 230 | /** \brief Invoked when a fetch job is completed, either |
| 231 | * successfully or unsuccessfully. |
| 232 | * |
| 233 | * Resets the status information for the worker process. |
| 234 | */ |
| 235 | void ItemDone(); |
| 236 | |
| 237 | public: |
| 238 | |
| 239 | /** \brief The queue entry that is currently being downloaded. */ |
| 240 | pkgAcquire::Queue::QItem *CurrentItem; |
| 241 | |
| 242 | /** \brief The most recent status string received from the |
| 243 | * subprocess. |
| 244 | */ |
| 245 | std::string Status; |
| 246 | |
| 247 | /** \brief How many bytes of the file have been downloaded. Zero |
| 248 | * if the current progress of the file cannot be determined. |
| 249 | */ |
| 250 | unsigned long long CurrentSize; |
| 251 | |
| 252 | /** \brief The total number of bytes to be downloaded. Zero if the |
| 253 | * total size of the final is unknown. |
| 254 | */ |
| 255 | unsigned long long TotalSize; |
| 256 | |
| 257 | /** \brief How much of the file was already downloaded prior to |
| 258 | * starting this worker. |
| 259 | */ |
| 260 | unsigned long long ResumePoint; |
| 261 | |
| 262 | /** \brief Tell the subprocess to download the given item. |
| 263 | * |
| 264 | * \param Item the item to queue up. |
| 265 | * \return \b true if the item was successfully enqueued. |
| 266 | * |
| 267 | * Queues up a 600 URI Acquire message for the given item to be |
| 268 | * sent at the next possible moment. Does \e not flush the output |
| 269 | * queue. |
| 270 | */ |
| 271 | bool QueueItem(pkgAcquire::Queue::QItem *Item); |
| 272 | |
| 273 | /** \brief Start up the worker and fill in #Config. |
| 274 | * |
| 275 | * Reads the first message from the worker, which is assumed to be |
| 276 | * a 100 Capabilities message. |
| 277 | * |
| 278 | * \return \b true if all operations completed successfully. |
| 279 | */ |
| 280 | bool Start(); |
| 281 | |
| 282 | /** \brief Update the worker statistics (CurrentSize, TotalSize, |
| 283 | * etc). |
| 284 | */ |
| 285 | void Pulse(); |
| 286 | |
| 287 | /** \return The fetch method configuration. */ |
| 288 | inline const MethodConfig *GetConf() const {return Config;}; |
| 289 | |
| 290 | /** \brief Create a new Worker to download files. |
| 291 | * |
| 292 | * \param OwnerQ The queue into which this worker should be |
| 293 | * placed. |
| 294 | * |
| 295 | * \param Config A location in which to store information about |
| 296 | * the fetch method. |
| 297 | * |
| 298 | * \param Log The download progress indicator that should be used |
| 299 | * to report the progress of this worker. |
| 300 | */ |
| 301 | Worker(Queue *OwnerQ,MethodConfig *Config,pkgAcquireStatus *Log); |
| 302 | |
| 303 | /** \brief Create a new Worker that should just retrieve |
| 304 | * information about the fetch method. |
| 305 | * |
| 306 | * Nothing in particular forces you to refrain from actually |
| 307 | * downloading stuff, but the various status callbacks won't be |
| 308 | * invoked. |
| 309 | * |
| 310 | * \param Config A location in which to store information about |
| 311 | * the fetch method. |
| 312 | */ |
| 313 | Worker(MethodConfig *Config); |
| 314 | |
| 315 | /** \brief Clean up this worker. |
| 316 | * |
| 317 | * Closes the file descriptors; if MethodConfig::NeedsCleanup is |
| 318 | * \b false, also rudely interrupts the worker with a SIGINT. |
| 319 | */ |
| 320 | virtual ~Worker(); |
| 321 | }; |
| 322 | |
| 323 | /** @} */ |
| 324 | |
| 325 | #endif |