pkgAcquire::Queue Class Reference

A single download queue in a pkgAcquire object. More...

#include <acquire.h>

Collaboration diagram for pkgAcquire::Queue:

Classes
struct	QItem
	A single item placed in this queue. More...

Public Member Functions
	Queue (std::string Name, pkgAcquire *Owner)
	Create a new Queue. More...
virtual	~Queue ()
	Shut down all the worker processes associated with this queue and empty the queue. More...
void	Bump ()
	Check for items that could be enqueued. More...
bool	Cycle ()
	Send idle items to the worker process. More...
bool	Dequeue (Item *Owner)
	Remove all fetch requests for the given item from this queue. More...
bool	Enqueue (ItemDesc &Item)
	Insert the given fetch request into this queue. More...
QItem *	FindItem (std::string URI, pkgAcquire::Worker *Owner)
	Locate an item in this queue. More...
bool	ItemDone (QItem *Itm)
	Remove the given item from this queue and set its state to pkgAcquire::Item::StatDone. More...
bool	ItemStart (QItem *Itm, unsigned long long Size)
	Presumably this should start downloading an item? More...
bool	Shutdown (bool Final)
	Shut down the worker process associated with this queue. More...
bool	Startup ()
	Start the worker process associated with this queue. More...

Protected Attributes
QItem *	Items
	The head of the list of items contained in this queue. More...
unsigned long	MaxPipeDepth
	The maximum number of entries that this queue will attempt to download at once. More...
std::string	Name
	The name of this queue. More...
pkgAcquire *	Owner
	the download scheduler with which this queue is associated. More...
signed long	PipeDepth
	The number of entries in this queue that are currently being downloaded. More...
pkgAcquire::Worker *	Workers
	The head of the list of workers associated with this queue. More...

Private Attributes
void *	d
	dpointer placeholder (for later in case we need it) More...
Queue *	Next
	The next queue in the pkgAcquire object's list of queues. More...

Friends
class	pkgAcquire
class	pkgAcquire::UriIterator
class	pkgAcquire::Worker

Detailed Description

A single download queue in a pkgAcquire object.

    {{{

Todo:

Why so many protected values?

Constructor & Destructor Documentation

pkgAcquire::Queue::Queue	(	std::string	Name,
		pkgAcquire *	Owner
	)

Create a new Queue.

Parameters

Name	The name of the new queue.
Owner	The download process that owns the new queue.

virtual pkgAcquire::Queue::~Queue ( )

virtual

Shut down all the worker processes associated with this queue and empty the queue.

Member Function Documentation

void pkgAcquire::Queue::Bump

(

)

Check for items that could be enqueued.

Call this after an item placed in multiple queues has gone from the pkgAcquire::Item::StatFetching state to the pkgAcquire::Item::StatIdle state, to possibly refill an empty queue. This is an alias for Cycle().

Todo:

Why both this and Cycle()? Are they expected to be different someday?

bool pkgAcquire::Queue::Cycle

(

)

Send idle items to the worker process.

Fills up the pipeline by inserting idle items into the worker's queue.

bool pkgAcquire::Queue::Dequeue

(

Item *

Owner

)

Remove all fetch requests for the given item from this queue.

Returns

true if at least one request was removed from the queue.

bool pkgAcquire::Queue::Enqueue

(

ItemDesc &

Item

)

Insert the given fetch request into this queue.

Returns

true if the queuing was successful. May return false if the Item is already in the queue

QItem* pkgAcquire::Queue::FindItem	(	std::string	URI,
		pkgAcquire::Worker *	Owner
	)

Locate an item in this queue.

Parameters

URI	A URI to match against.
Owner	A pkgAcquire::Worker to match against.

Returns

the first item in the queue whose URI is URI and that is being downloaded by Owner.

bool pkgAcquire::Queue::ItemDone

(

QItem *

Itm

)

Remove the given item from this queue and set its state to pkgAcquire::Item::StatDone.

If this is the only queue containing the item, the item is also removed from the main queue by calling pkgAcquire::Dequeue.

Parameters

Itm	The item to remove.

Returns

true if no errors are encountered.

bool pkgAcquire::Queue::ItemStart	(	QItem *	Itm,
		unsigned long long	Size
	)

Presumably this should start downloading an item?

Todo:

Unimplemented. Implement it or remove?

bool pkgAcquire::Queue::Shutdown

(

bool

Final

)

Shut down the worker process associated with this queue.

Parameters

Final

If true, then the process is stopped unconditionally. Otherwise, it is only stopped if it does not need cleanup as indicated by the pkgAcqMethod::NeedsCleanup member of its configuration.

Returns

true.

bool pkgAcquire::Queue::Startup

(

)

Start the worker process associated with this queue.

If a worker process is already associated with this queue, this is equivalent to calling Cycle().

Returns

true if the startup was successful.

Friends And Related Function Documentation

friend class pkgAcquire

friend

friend class pkgAcquire::UriIterator

friend

friend class pkgAcquire::Worker

friend

Member Data Documentation

void* pkgAcquire::Queue::d

private

dpointer placeholder (for later in case we need it)

QItem* pkgAcquire::Queue::Items

protected

The head of the list of items contained in this queue.

Todo:

why a by-hand list instead of an STL structure?

Referenced by pkgAcquire::UriIterator::operator++(), and pkgAcquire::UriIterator::UriIterator().

unsigned long pkgAcquire::Queue::MaxPipeDepth

protected

The maximum number of entries that this queue will attempt to download at once.

std::string pkgAcquire::Queue::Name

protected

The name of this queue.

Queue* pkgAcquire::Queue::Next

private

The next queue in the pkgAcquire object's list of queues.

Referenced by pkgAcquire::UriIterator::operator++(), and pkgAcquire::UriIterator::UriIterator().

pkgAcquire* pkgAcquire::Queue::Owner

protected

the download scheduler with which this queue is associated.

signed long pkgAcquire::Queue::PipeDepth

protected

The number of entries in this queue that are currently being downloaded.

pkgAcquire::Worker* pkgAcquire::Queue::Workers

protected

The head of the list of workers associated with this queue.

Todo:

This is plural because support exists in Queue for multiple workers. However, it does not appear that there is any way to actually associate more than one worker with a queue.

Todo:

Why not just use a std::set?

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The documentation for this class was generated from the following file:

• /usr/include/apt-pkg/acquire.h