##################################################################### */
/*}}}*/
+
+/** \addtogroup acquire
+ * @{
+ *
+ * \file acquire-worker.h
+ */
+
#ifndef PKGLIB_ACQUIRE_WORKER_H
#define PKGLIB_ACQUIRE_WORKER_H
#include <apt-pkg/acquire.h>
-// 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;
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
projects / apt.git / blobdiff