diff options
Diffstat (limited to 'apt-pkg/acquire-worker.h')
| -rw-r--r-- | apt-pkg/acquire-worker.h | 262 |
1 files changed, 247 insertions, 15 deletions
diff --git a/apt-pkg/acquire-worker.h b/apt-pkg/acquire-worker.h index 6e1952202..2942df69f 100644 --- a/apt-pkg/acquire-worker.h +++ b/apt-pkg/acquire-worker.h @@ -9,16 +9,38 @@ ##################################################################### */ /*}}}*/ + +/** \addtogroup acquire + * @{ + * + * \file acquire-worker.h + */ + #ifndef PKGLIB_ACQUIRE_WORKER_H #define PKGLIB_ACQUIRE_WORKER_H #include <apt-pkg/acquire.h> -#ifdef __GNUG__ -#pragma interface "apt-pkg/acquire-worker.h" -#endif -// Interfacing to the method process +/** \brief A fetch subprocess. + * + * A worker process is responsible for one stage of the fetch. This + * class encapsulates the communications protocol between the master + * process and the worker, from the master end. + * + * Each worker is intrinsically placed on two linked lists. The + * Queue list (maintained in the #NextQueue variable) is maintained + * by the pkgAcquire::Queue class; it represents the set of workers + * assigned to a particular queue. The Acquire list (maintained in + * the #NextAcquire variable) is maintained by the pkgAcquire class; + * it represents the set of active workers for a particular + * pkgAcquire object. + * + * \todo Like everything else in the Acquire system, this has way too + * many protected items. + * + * \sa pkgAcqMethod, pkgAcquire::Item, pkgAcquire + */ class pkgAcquire::Worker { friend class pkgAcquire; @@ -26,64 +48,274 @@ class pkgAcquire::Worker protected: friend class Queue; - /* Linked list starting at a Queue and a linked list starting - at Acquire */ + /** \brief The next link on the Queue list. + * + * \todo This is always NULL; is it just for future use? + */ Worker *NextQueue; + + /** \brief The next link on the Acquire list. */ Worker *NextAcquire; - // The access association + /** \brief The Queue with which this worker is associated. */ Queue *OwnerQ; + + /** \brief The download progress indicator to which progress + * messages should be sent. + */ pkgAcquireStatus *Log; + + /** \brief The configuration of this method. On startup, the + * target of this pointer is filled in with basic data about the + * method, as reported by the worker. + */ MethodConfig *Config; + + /** \brief The access method to be used by this worker. + * + * \todo Doesn't this duplicate Config->Access? + */ string Access; - // This is the subprocess IPC setup + /** \brief The PID of the subprocess. */ pid_t Process; + + /** \brief A file descriptor connected to the standard output of + * the subprocess. + * + * Used to read messages and data from the subprocess. + */ int InFd; + + /** \brief A file descriptor connected to the standard input of the + * subprocess. + * + * Used to send commands and configuration data to the subprocess. + */ int OutFd; + + /** \brief Set to \b true if the worker is in a state in which it + * might generate data or command responses. + * + * \todo Is this right? It's a guess. + */ bool InReady; + + /** \brief Set to \b true if the worker is in a state in which it + * is legal to send commands to it. + * + * \todo Is this right? + */ bool OutReady; - // Various internal things + /** If \b true, debugging output will be sent to std::clog. */ bool Debug; + + /** \brief The raw text values of messages received from the + * worker, in sequence. + */ vector<string> MessageQueue; + + /** \brief Buffers pending writes to the subprocess. + * + * \todo Wouldn't a std::dequeue be more appropriate? + */ string OutQueue; - // Private constructor helper + /** \brief Common code for the constructor. + * + * Initializes NextQueue and NextAcquire to NULL; Process, InFd, + * and OutFd to -1, OutReady and InReady to \b false, and Debug + * from _config. + */ void Construct(); - // Message handling things + /** \brief Retrieve any available messages from the subprocess. + * + * The messages are retrieved as in ::ReadMessages(), and + * MessageFailure() is invoked if an error occurs; in particular, + * if the pipe to the subprocess dies unexpectedly while a message + * is being read. + * + * \return \b true if the messages were successfully read, \b + * false otherwise. + */ bool ReadMessages(); + + /** \brief Parse and dispatch pending messages. + * + * This dispatches the message in a manner appropriate for its + * type. + * + * \todo Several message types lack separate handlers. + * + * \sa Capabilities(), SendConfiguration(), MediaChange() + */ bool RunMessages(); + + /** \brief Read and dispatch any pending messages from the + * subprocess. + * + * \return \b false if the subprocess died unexpectedly while a + * message was being transmitted. + */ bool InFdReady(); + + /** \brief Send any pending commands to the subprocess. + * + * This method will fail if there is no pending output. + * + * \return \b true if all commands were succeeded, \b false if an + * error occurred (in which case MethodFailure() will be invoked). + */ bool OutFdReady(); - // The message handlers + /** \brief Handle a 100 Capabilities response from the subprocess. + * + * \param Message the raw text of the message from the subprocess. + * + * The message will be parsed and its contents used to fill + * #Config. If #Config is NULL, this routine is a NOP. + * + * \return \b true. + */ bool Capabilities(string Message); + + /** \brief Send a 601 Configuration message (containing the APT + * configuration) to the subprocess. + * + * The APT configuration will be send to the subprocess in a + * message of the following form: + * + * <pre> + * 601 Configuration + * Config-Item: Fully-Qualified-Item=Val + * Config-Item: Fully-Qualified-Item=Val + * ... + * </pre> + * + * \return \b true if the command was successfully sent, \b false + * otherwise. + */ bool SendConfiguration(); + + /** \brief Handle a 403 Media Change message. + * + * \param Message the raw text of the message; the Media field + * indicates what type of media should be changed, and the Drive + * field indicates where the media is located. + * + * Invokes pkgAcquireStatus::MediaChange(Media, Drive) to ask the + * user to swap disks; informs the subprocess of the result (via + * 603 Media Changed, with the Failed field set to \b true if the + * user cancelled the media change). + */ bool MediaChange(string Message); + /** \brief Invoked when the worked process dies unexpectedly. + * + * Waits for the subprocess to terminate and generates an error if + * it terminated abnormally, then closes and blanks out all file + * descriptors. Discards all pending messages from the + * subprocess. + * + * \return \b false. + */ bool MethodFailure(); + + /** \brief Invoked when a fetch job is completed, either + * successfully or unsuccessfully. + * + * Resets the status information for the worker process. + */ void ItemDone(); public: - // The curent method state + /** \brief The queue entry that is currently being downloaded. */ pkgAcquire::Queue::QItem *CurrentItem; + + /** \brief The most recent status string received from the + * subprocess. + */ string Status; + + /** \brief How many bytes of the file have been downloaded. Zero + * if the current progress of the file cannot be determined. + */ unsigned long CurrentSize; + + /** \brief The total number of bytes to be downloaded. Zero if the + * total size of the final is unknown. + */ unsigned long TotalSize; + + /** \brief How much of the file was already downloaded prior to + * starting this worker. + */ unsigned long ResumePoint; - // Load the method and do the startup + /** \brief Tell the subprocess to download the given item. + * + * \param Item the item to queue up. + * \return \b true if the item was successfully enqueued. + * + * Queues up a 600 URI Acquire message for the given item to be + * sent at the next possible moment. Does \e not flush the output + * queue. + */ bool QueueItem(pkgAcquire::Queue::QItem *Item); + + /** \brief Start up the worker and fill in #Config. + * + * Reads the first message from the worker, which is assumed to be + * a 100 Capabilities message. + * + * \return \b true if all operations completed successfully. + */ bool Start(); + + /** \brief Update the worker statistics (CurrentSize, TotalSize, + * etc). + */ void Pulse(); + + /** \return The fetch method configuration. */ inline const MethodConfig *GetConf() const {return Config;}; - + + /** \brief Create a new Worker to download files. + * + * \param OwnerQ The queue into which this worker should be + * placed. + * + * \param Config A location in which to store information about + * the fetch method. + * + * \param Log The download progress indicator that should be used + * to report the progress of this worker. + */ Worker(Queue *OwnerQ,MethodConfig *Config,pkgAcquireStatus *Log); + + /** \brief Create a new Worker that should just retrieve + * information about the fetch method. + * + * Nothing in particular forces you to refrain from actually + * downloading stuff, but the various status callbacks won't be + * invoked. + * + * \param Config A location in which to store information about + * the fetch method. + */ Worker(MethodConfig *Config); + + /** \brief Clean up this worker. + * + * Closes the file descriptors; if MethodConfig::NeedsCleanup is + * \b false, also rudely interrupts the worker with a SIGINT. + */ ~Worker(); }; +/** @} */ + #endif |