dcmtk::log4cplus::thread::Queue Class Reference

Single consumer, multiple producers queue. More...

Inheritance diagram for dcmtk::log4cplus::thread::Queue:

Public Types
enum	Flags {   EVENT = 0x0001, QUEUE = 0x0002, EXIT = 0x0004, DRAIN = 0x0008,   ERROR_BIT = 0x0010, ERROR_AFTER = 0x0020 }
	Possible state flags. More...
typedef unsigned	flags_type
	Type of the state flags field.
typedef OFVector < spi::InternalLoggingEvent >	queue_storage_type
	Queue storage type.

Public Member Functions
flags_type	put_event (spi::InternalLoggingEvent const &ev)
	Puts event ev into queue, sets QUEUE flag and sets internal event object into signaled state. More...
flags_type	signal_exit (bool drain=true)
	Sets EXIT flag and DRAIN flag and sets internal event object into signaled state. More...
flags_type	get_events (queue_storage_type *buf)
	The get_events() function is used by queue's consumer. More...

Protected Attributes
queue_storage_type	queue
	Queue storage.
Mutex	mutex
	Mutex protecting queue and flags.
ManualResetEvent	ev_consumer
	Event on which consumer can wait if it finds queue empty.
Semaphore	sem
	Semaphore that limits the queue length.
flags_type	flags
	State flags.

Detailed Description

Single consumer, multiple producers queue.

Member Enumeration Documentation

enum dcmtk::log4cplus::thread::Queue::Flags

Possible state flags.

Enumerator
EVENT	EVENT flag is set in return value of get_event() call if the ev argument is filled with event from the queue.
QUEUE	QUEUE flag is set by producers when they put item into the queue.
EXIT	EXIT flag is set by signal_exit() call, signaling that the queue worker thread should end itself.
DRAIN	When DRAIN flag is set together with EXIT flag, the queue worker thread will first drain the queue before exiting.
ERROR_BIT	ERROR_BIT signals error.
ERROR_AFTER	ERROR_AFTER signals error that has occured after queue has already been touched.

Member Function Documentation

flags_type dcmtk::log4cplus::thread::Queue::get_events

(

queue_storage_type *

buf

)

The get_events() function is used by queue's consumer.

It fills buf argument and sets EVENT flag in return value. If EXIT flag is already set in flags member upon entering the function then depending on DRAIN flag it either fills buf argument or does not fill the argument, if the queue is non-empty. The function blocks by waiting for internal event object to be signaled if the queue is empty, unless EXIT flag is set. The calling thread is unblocked when items are added into the queue or when exit is signaled using the signal_exit() function.

Upon error, return value has one of the error flags set.

Parameters

buf	Pointer to storage of spi::InternalLoggingEvent instances to be filled from queue.

Returns

Flags.

flags_type dcmtk::log4cplus::thread::Queue::put_event

(

spi::InternalLoggingEvent const &

ev

)

Puts event ev into queue, sets QUEUE flag and sets internal event object into signaled state.

If the EXIT flags is already set upon entering the function, nothing is inserted into the queue. The function can block on internal semaphore if the queue has reached maximal allowed length. Calling thread is unblocked either by consumer thread removing item from queue or by any other thread calling signal_exit().

Parameters

ev	spi::InternalLoggingEvent to be put into the queue.

Returns

Flags.

flags_type dcmtk::log4cplus::thread::Queue::signal_exit

(

bool

drain = true

)

Sets EXIT flag and DRAIN flag and sets internal event object into signaled state.

Parameters

drain

If true, DRAIN flag will be set, otherwise unset.

Returns

Flags, ERROR_BIT can be set upon error.

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

• oflog/include/dcmtk/oflog/helpers/queue.h