ACE_Message_Block Class Reference

Stores messages for use throughout ACE (particularly in an ACE_Message_Queue). More...

#include <Message_Block.h>

Collaboration diagram for ACE_Message_Block:

Public Types
enum	{   MB_DATA = 0x01 , MB_PROTO = 0x02 , MB_BREAK = 0x03 , MB_PASSFP = 0x04 ,   MB_EVENT = 0x05 , MB_SIG = 0x06 , MB_IOCTL = 0x07 , MB_SETOPTS = 0x08 ,   MB_IOCACK = 0x81 , MB_IOCNAK = 0x82 , MB_PCPROTO = 0x83 , MB_PCSIG = 0x84 ,   MB_READ = 0x85 , MB_FLUSH = 0x86 , MB_STOP = 0x87 , MB_START = 0x88 ,   MB_HANGUP = 0x89 , MB_ERROR = 0x8a , MB_PCEVENT = 0x8b , MB_NORMAL = 0x00 ,   MB_PRIORITY = 0x80 , MB_USER = 0x200 }
enum	{ DONT_DELETE = 01 , USER_FLAGS = 0x1000 }
typedef int	ACE_Message_Type
typedef unsigned long	Message_Flags

Public Member Functions
	ACE_Message_Block (ACE_Allocator *message_block_allocator=0)
	Create an empty message.
	ACE_Message_Block (ACE_Data_Block *data_block, Message_Flags flags=0, ACE_Allocator *message_block_allocator=0)
	ACE_Message_Block (const char *data, size_t size=0, unsigned long priority=ACE_DEFAULT_MESSAGE_BLOCK_PRIORITY)
	ACE_Message_Block (size_t size, ACE_Message_Type type=MB_DATA, ACE_Message_Block *cont=nullptr, const char *data=nullptr, ACE_Allocator *allocator_strategy=nullptr, ACE_Lock *locking_strategy=nullptr, unsigned long priority=ACE_DEFAULT_MESSAGE_BLOCK_PRIORITY, const ACE_Time_Value &execution_time=ACE_Time_Value::zero, const ACE_Time_Value &deadline_time=ACE_Time_Value::max_time, ACE_Allocator *data_block_allocator=nullptr, ACE_Allocator *message_block_allocator=nullptr)
	ACE_Message_Block (const ACE_Message_Block &mb, size_t align)
int	init (const char *data, size_t size=0)
int	init (size_t size, ACE_Message_Type type=MB_DATA, ACE_Message_Block *cont=0, const char *data=0, ACE_Allocator *allocator_strategy=0, ACE_Lock *locking_strategy=0, unsigned long priority=ACE_DEFAULT_MESSAGE_BLOCK_PRIORITY, const ACE_Time_Value &execution_time=ACE_Time_Value::zero, const ACE_Time_Value &deadline_time=ACE_Time_Value::max_time, ACE_Allocator *data_block_allocator=0, ACE_Allocator *message_block_allocator=0)
virtual	~ACE_Message_Block ()
ACE_Message_Type	msg_type () const
	Get type of the message.
void	msg_type (ACE_Message_Type type)
	Set type of the message.
int	is_data_msg () const
	Find out what type of message this is.
ACE_Message_Type	msg_class () const
Message_Flags	set_flags (Message_Flags more_flags)
Message_Flags	clr_flags (Message_Flags less_flags)
Message_Flags	flags () const
	Get the current message flags.
Message_Flags	set_self_flags (ACE_Message_Block::Message_Flags more_flags)
Message_Flags	clr_self_flags (ACE_Message_Block::Message_Flags less_flags)
Message_Flags	self_flags () const
	Get the current message flags.
unsigned long	msg_priority () const
	Get priority of the message.
void	msg_priority (unsigned long priority)
	Set priority of the message.
const ACE_Time_Value &	msg_execution_time () const
	Get execution time associated with the message.
void	msg_execution_time (const ACE_Time_Value &et)
	Set execution time associated with the message.
const ACE_Time_Value &	msg_deadline_time () const
	Get absolute time of deadline associated with the message.
void	msg_deadline_time (const ACE_Time_Value &dt)
	Set absolute time of deadline associated with the message.
virtual ACE_Message_Block *	clone (Message_Flags mask=0) const
virtual ACE_Message_Block *	duplicate () const
	Return a "shallow" copy that increments our reference count by 1.
virtual ACE_Message_Block *	release ()
int	copy (const char *buf, size_t n)
int	copy (const char *buf)
int	crunch ()
void	reset ()
void	access_allocators (ACE_Allocator *&allocator_strategy, ACE_Allocator *&data_block_allocator, ACE_Allocator *&message_block_allocator)
void	reset_allocators (ACE_Allocator *allocator_strategy=0, ACE_Allocator *data_block_allocator=0, ACE_Allocator *message_block_allocator=0)
char *	base () const
	Get message data.
void	base (char *data, size_t size, Message_Flags=DONT_DELETE)
	Set message data (doesn't reallocate).
char *	end () const
	Return a pointer to 1 past the end of the allocated data in a message.
char *	mark () const
char *	rd_ptr () const
	Get the read pointer.
void	rd_ptr (char *ptr)
	Set the read pointer to ptr.
void	rd_ptr (size_t n)
	Set the read pointer ahead n bytes.
char *	wr_ptr () const
	Get the write pointer.
void	wr_ptr (char *ptr)
	Set the write pointer to ptr.
void	wr_ptr (size_t n)

Static Public Member Functions
static ACE_Message_Block *	duplicate (const ACE_Message_Block *mb)
static ACE_Message_Block *	release (ACE_Message_Block *mb)

Friends
class	ACE_Data_Block

Message length and size operations
Message length is (wr_ptr - rd_ptr). Message size is capacity of the message, including data outside the [rd_ptr,wr_ptr] range.
	ACE_ALLOC_HOOK_DECLARE
	Declare the dynamic allocation hooks.
size_t	rd_ptr_
	Pointer to beginning of next read.
size_t	wr_ptr_
	Pointer to beginning of next write.
unsigned long	priority_
	Priority of message.
ACE_Message_Block *	cont_
	Pointer to next message block in the chain.
ACE_Message_Block *	next_
	Pointer to next message in the list.
ACE_Message_Block *	prev_
	Pointer to previous message in the list.
ACE_Message_Block::Message_Flags	flags_
	Misc flags (e.g., DONT_DELETE and USER_FLAGS).
ACE_Data_Block *	data_block_
ACE_Allocator *	message_block_allocator_
size_t	length () const
	Get the length of the message.
void	length (size_t n)
	Set the length of the message.
size_t	total_length () const
size_t	total_size () const
void	total_size_and_length (size_t &mb_size, size_t &mb_length) const
size_t	size () const
int	size (size_t length)
size_t	total_capacity () const
size_t	capacity () const
	Get the number of allocated bytes in the top-level Message_Block.
size_t	space () const
ACE_Data_Block *	data_block () const
void	data_block (ACE_Data_Block *)
ACE_Data_Block *	replace_data_block (ACE_Data_Block *)
ACE_Message_Block *	cont () const
	Get the continuation field.
void	cont (ACE_Message_Block *)
	Set the continuation field.
ACE_Message_Block *	next () const
	Get link to next message.
void	next (ACE_Message_Block *)
	Set link to next message.
ACE_Message_Block *	prev () const
	Get link to prev message.
void	prev (ACE_Message_Block *)
	Set link to prev message.
ACE_Lock *	locking_strategy ()
	Get the locking strategy.
ACE_Lock *	locking_strategy (ACE_Lock *)
	Set a new locking strategy and return the hold one.
int	reference_count () const
	Get the current reference count.
void	dump () const
	Dump the state of an object.
	ACE_Message_Block (size_t size, ACE_Message_Type type, ACE_Message_Block *cont, const char *data, ACE_Allocator *allocator_strategy, ACE_Lock *locking_strategy, Message_Flags flags, unsigned long priority, const ACE_Time_Value &execution_time, const ACE_Time_Value &deadline_time, ACE_Data_Block *db, ACE_Allocator *data_block_allocator, ACE_Allocator *message_block_allocator)
	Perform the actual initialization.
int	release_i (ACE_Lock *lock)
int	init_i (size_t size, ACE_Message_Type type, ACE_Message_Block *cont, const char *data, ACE_Allocator *allocator_strategy, ACE_Lock *locking_strategy, Message_Flags flags, unsigned long priority, const ACE_Time_Value &execution_time, const ACE_Time_Value &deadline_time, ACE_Data_Block *db, ACE_Allocator *data_block_allocator, ACE_Allocator *message_block_allocator)
	Perform the actual initialization.
ACE_Message_Block &	operator= (const ACE_Message_Block &)
	Declare the dynamic allocation hooks.
	ACE_Message_Block (const ACE_Message_Block &)
	Declare the dynamic allocation hooks.

Detailed Description

Stores messages for use throughout ACE (particularly in an ACE_Message_Queue).

An ACE_Message_Block is modeled after the message data structures used in System V STREAMS. Its purpose is to enable efficient manipulation of arbitrarily large messages without incurring much memory copying overhead. Here are the main characteristics of an ACE_Message_Block:

• Contains a pointer to a reference-counted ACE_Data_Block, which in turn points to the actual data buffer. This allows very flexible and efficient sharing of data by multiple ACE_Message_Block objects.
• One or more ACE_Message_Blocks can be linked to form a `‘fragment chain.’'
• ACE_Message_Blocks can be linked together in a doubly linked fashion to form a queue of messages (this is how ACE_Message_Queue works).

See also

C++NPv1, section 4.2; APG, section 12.3.2.

Member Typedef Documentation

ACE_Message_Type

typedef int ACE_Message_Block::ACE_Message_Type

Message_Flags

typedef unsigned long ACE_Message_Block::Message_Flags

Member Enumeration Documentation

anonymous enum

anonymous enum

Enumerator
MB_DATA	Undifferentiated data message.
MB_PROTO	Undifferentiated protocol control.
MB_BREAK	Line break (regular and priority)
MB_PASSFP	Pass file pointer.
MB_EVENT	Post an event to an event queue.
MB_SIG	Generate process signal.
MB_IOCTL	ioctl; set/get params
MB_SETOPTS	Set various stream head options.
MB_IOCACK	Acknowledge ioctl (high priority; go to head of queue)
MB_IOCNAK	Negative ioctl acknowledge.
MB_PCPROTO	Priority proto message.
MB_PCSIG	Generate process signal.
MB_READ	Generate read notification.
MB_FLUSH	Flush your queues.
MB_STOP	Stop transmission immediately.
MB_START	Restart transmission after stop.
MB_HANGUP	Line disconnect.
MB_ERROR	Fatal error used to set u.u_error.
MB_PCEVENT	Post an event to an event queue.
MB_NORMAL	Normal priority message mask.
MB_PRIORITY	High priority control message mask.
MB_USER	User-defined message mask.

anonymous enum

anonymous enum

Enumerator
DONT_DELETE	Don't delete the data on exit since we don't own it.
USER_FLAGS	user defined flags start here

Constructor & Destructor Documentation

ACE_Message_Block() [1/7]

ACE_Message_Block::ACE_Message_Block

(

ACE_Allocator *

message_block_allocator = 0

)

Create an empty message.

ACE_Message_Block() [2/7]

ACE_Message_Block::ACE_Message_Block	(	ACE_Data_Block *	data_block,
		ACE_Message_Block::Message_Flags	flags = 0,
		ACE_Allocator *	message_block_allocator = 0 )

Create an ACE_Message_Block that owns the specified ACE_Data_Block without copying it. If the flags is set to DONT_DELETE we don't delete the ACE_Data_Block. It is left to the client's responsibility to take care of the memory allocated for the data_block

ACE_Message_Block() [3/7]

ACE_Message_Block::ACE_Message_Block	(	const char *	data,
		size_t	size = 0,
		unsigned long	priority = ACE_DEFAULT_MESSAGE_BLOCK_PRIORITY )

Create an ACE_Message_Block that refers to data without copying it. The data memory will not be freed when this block is destroyed; memory management of data is left to the caller. Note that the size of the new ACE_Message_Block will be size, but the length will be 0 until the write pointer is changed.

ACE_Message_Block() [4/7]

ACE_Message_Block::ACE_Message_Block	(	size_t	size,
		ACE_Message_Type	type = MB_DATA,
		ACE_Message_Block *	cont = nullptr,
		const char *	data = nullptr,
		ACE_Allocator *	allocator_strategy = nullptr,
		ACE_Lock *	locking_strategy = nullptr,
		unsigned long	priority = ACE_DEFAULT_MESSAGE_BLOCK_PRIORITY,
		const ACE_Time_Value &	execution_time = ACE_Time_Value::zero,
		const ACE_Time_Value &	deadline_time = ACE_Time_Value::max_time,
		ACE_Allocator *	data_block_allocator = nullptr,
		ACE_Allocator *	message_block_allocator = nullptr )

Create an initialized message of type type containing size bytes. The cont argument initializes the continuation field in the ACE_Message_Block. If data == 0 then this block allocates and owns the block's memory, using allocator to get the data if it's non-0. If data != 0 then this block refers to that memory until this this block ceases to exist; this object will not free data on destruction. If locking_strategy is non-0 then this is used to protect regions of code that access shared state (e.g., reference counting) from race conditions. Note that the size of the ACE_Message_Block will be size, but the length will be 0 until the write pointer is set. The data_block_allocator is used to allocate the data blocks while the allocator_strategy is used to allocate the buffers contained by those. The message_block_allocator is used to allocate new ACE_Message_Block objects when the duplicate() method is called. If a message_block_allocator is given, this ACE_Message_Block and future ACE_Message_Block objects created by duplicate() will be freed using this allocator when they are released.

Note

If you use this allocator, the ACE_Message_Block you created should have been created using this allocator because it will be released to the same allocator.

ACE_Message_Block() [5/7]

ACE_Message_Block::ACE_Message_Block	(	const ACE_Message_Block &	mb,
		size_t	align )

A copy constructor. This constructor is a bit different. If the incoming Message Block has a data block from the stack this constructor does a deep copy ie. allocates a new data block on the heap and does a copy of the data from the incoming message block. As a final note, the alignment information is used to align the data block if it is created afresh. If the incoming mb has a data block has a data block allocated from the heap, then this constructor just duplicates (ie. a shallow copy) the data block of the incoming mb.

~ACE_Message_Block()

ACE_Message_Block::~ACE_Message_Block ( )

virtual

Delete all the resources held in the message.

Note

Note that release() is designed to release the continuation chain; the destructor is not. See release() for details.

ACE_Message_Block() [6/7]

ACE_Message_Block::ACE_Message_Block ( size_t size, ACE_Message_Type type, ACE_Message_Block * cont, const char * data, ACE_Allocator * allocator_strategy, ACE_Lock * locking_strategy, Message_Flags flags, unsigned long priority, const ACE_Time_Value & execution_time, const ACE_Time_Value & deadline_time, ACE_Data_Block * db, ACE_Allocator * data_block_allocator, ACE_Allocator * message_block_allocator )

protected

Perform the actual initialization.

ACE_Message_Block() [7/7]

ACE_Message_Block::ACE_Message_Block ( const ACE_Message_Block & )

private

Declare the dynamic allocation hooks.

Member Function Documentation

access_allocators()

void ACE_Message_Block::access_allocators ( ACE_Allocator *& allocator_strategy, ACE_Allocator *& data_block_allocator, ACE_Allocator *& message_block_allocator )

inline

Access all the allocators in the message block.

Todo

Not sure whether we would need finer control while trying to access allocators ie. a method for every allocator.

This method returns the allocators only from the first message block in the chain.

Parameters

allocator_strategy	Strategy used to allocate the underlying buffer
data_block_allocator	Strategy used to allocate the underlying data block
message_block_allocator	Strategy used to allocate the message block

base() [1/2]

char * ACE_Message_Block::base ( ) const

inline

Get message data.

base() [2/2]

void ACE_Message_Block::base ( char * data, size_t size, Message_Flags msg_flags = DONT_DELETE )

inline

Set message data (doesn't reallocate).

capacity()

size_t ACE_Message_Block::capacity ( ) const

inline

Get the number of allocated bytes in the top-level Message_Block.

clone()

ACE_Message_Block * ACE_Message_Block::clone ( Message_Flags mask = 0 ) const

virtual

Return an exact "deep copy" of the message, i.e., create fresh new copies of all the Data_Blocks and continuations.

clr_flags()

ACE_Message_Block::Message_Flags ACE_Message_Block::clr_flags ( ACE_Message_Block::Message_Flags less_flags )

inline

Clear the message flag bits specified in less_flags and return the new value.

clr_self_flags()

ACE_Message_Block::Message_Flags ACE_Message_Block::clr_self_flags ( ACE_Message_Block::Message_Flags less_flags )

inline

Clear the message flag bits specified in less_flags and return the new value.

cont() [1/2]

ACE_Message_Block * ACE_Message_Block::cont ( ) const

inline

Get the continuation field.

cont() [2/2]

void ACE_Message_Block::cont ( ACE_Message_Block * cont_msg )

inline

Set the continuation field.

copy() [1/2]

int ACE_Message_Block::copy

(

const char *

buf

)

Copies a 0-terminated character string into this ACE_Message_Block. The string is copied into the block starting at the current write pointer. The 0-terminator is included in the copied data.

Parameters

buf	Pointer to the character string to copy from.

Return values

0	on success; the write pointer is advanced by the string's length, including the 0 terminator.
-1	if the amount of free space following the write pointer in the block is less than required to hold the entire string. Free space can be checked by calling space().

copy() [2/2]

int ACE_Message_Block::copy	(	const char *	buf,
		size_t	n )

Copies data into this ACE_Message_Block. Data is copied into the block starting at the current write pointer.

Parameters

buf	Pointer to the buffer to copy from.
n	The number of bytes to copy.

Return values

0	on success; the write pointer is advanced by n.
-1	if the amount of free space following the write pointer in the block is less than n. Free space can be checked by calling space().

crunch()

int ACE_Message_Block::crunch

(

)

Normalizes data in the top-level Message_Block to align with the base, i.e., it "shifts" the data pointed to by <rd_ptr> down to the <base> and then readjusts <rd_ptr> to point to <base> and <wr_ptr> to point to <base> + the length of the moved data. Returns -1 and does nothing if the <rd_ptr> is > <wr_ptr>, else 0 on success.

data_block() [1/2]

ACE_Data_Block * ACE_Message_Block::data_block ( ) const

inline

Get a pointer to the data block. Note that the ACE_Message_Block still references the block; this call does not change the reference count.

data_block() [2/2]

void ACE_Message_Block::data_block

(

ACE_Data_Block *

db

)

Set a new data block pointer. The original ACE_Data_Block is released as a result of this call. If you need to keep the original block, call <replace_data_block> instead. Upon return, this ACE_Message_Block holds a pointer to the new ACE_Data_Block, taking over the reference you held on it prior to the call.

dump()

void ACE_Message_Block::dump

(

)

const

Dump the state of an object.

duplicate() [1/2]

ACE_Message_Block * ACE_Message_Block::duplicate ( ) const

virtual

Return a "shallow" copy that increments our reference count by 1.

duplicate() [2/2]

ACE_Message_Block * ACE_Message_Block::duplicate ( const ACE_Message_Block * mb )

static

Return a "shallow" copy that increments our reference count by 1. This is similar to CORBA's _duplicate() method, which is useful if you want to eliminate lots of checks for NULL mb pointers before calling _duplicate() on them.

end()

char * ACE_Message_Block::end ( ) const

inline

Return a pointer to 1 past the end of the allocated data in a message.

flags()

ACE_Message_Block::Message_Flags ACE_Message_Block::flags ( ) const

inline

Get the current message flags.

init() [1/2]

int ACE_Message_Block::init	(	const char *	data,
		size_t	size = 0 )

Create a Message Block that assumes it has ownership of data, but in reality it doesn't (i.e., cannot delete it since it didn't malloc it!). Note that the size of the Message_Block will be size, but the length will be 0 until <wr_ptr> is set.

init() [2/2]

int ACE_Message_Block::init	(	size_t	size,
		ACE_Message_Type	type = MB_DATA,
		ACE_Message_Block *	cont = 0,
		const char *	data = 0,
		ACE_Allocator *	allocator_strategy = 0,
		ACE_Lock *	locking_strategy = 0,
		unsigned long	priority = ACE_DEFAULT_MESSAGE_BLOCK_PRIORITY,
		const ACE_Time_Value &	execution_time = ACE_Time_Value::zero,
		const ACE_Time_Value &	deadline_time = ACE_Time_Value::max_time,
		ACE_Allocator *	data_block_allocator = 0,
		ACE_Allocator *	message_block_allocator = 0 )

Create an initialized message of type type containing size bytes. The cont argument initializes the continuation field in the Message_Block. If data == 0 then we create and own the data, using allocator_strategy to get the data if it's non-0. If data != 0 we assume that we have ownership of the data till this object ceases to exist (and don't delete it during destruction). If locking_strategy is non-0 then this is used to protect regions of code that access shared state (e.g., reference counting) from race conditions. Note that the size of the Message_Block will be size, but the length will be 0 until <wr_ptr> is set. The data_block_allocator is use to allocate the data blocks while the allocator_strategy is used to allocate the buffers contained by those.

init_i()

int ACE_Message_Block::init_i ( size_t size, ACE_Message_Type type, ACE_Message_Block * cont, const char * data, ACE_Allocator * allocator_strategy, ACE_Lock * locking_strategy, Message_Flags flags, unsigned long priority, const ACE_Time_Value & execution_time, const ACE_Time_Value & deadline_time, ACE_Data_Block * db, ACE_Allocator * data_block_allocator, ACE_Allocator * message_block_allocator )

protected

Perform the actual initialization.

is_data_msg()

int ACE_Message_Block::is_data_msg ( ) const

inline

Find out what type of message this is.

length() [1/2]

size_t ACE_Message_Block::length ( ) const

inline

Get the length of the message.

length() [2/2]

void ACE_Message_Block::length ( size_t n )

inline

Set the length of the message.

locking_strategy() [1/2]

ACE_Lock * ACE_Message_Block::locking_strategy ( )

inline

Get the locking strategy.

locking_strategy() [2/2]

ACE_Lock * ACE_Message_Block::locking_strategy ( ACE_Lock * nls )

inline

Set a new locking strategy and return the hold one.

mark()

char * ACE_Message_Block::mark ( ) const

inline

Return a pointer to 1 past the end of the allotted data in a message. Allotted data may be less than allocated data if a value smaller than capacity() to is passed to size().

msg_class()

ACE_Message_Block::ACE_Message_Type ACE_Message_Block::msg_class ( ) const

inline

Find out what class of message this is (there are two classes, normal messages and high-priority messages).

msg_deadline_time() [1/2]

const ACE_Time_Value & ACE_Message_Block::msg_deadline_time ( ) const

inline

Get absolute time of deadline associated with the message.

msg_deadline_time() [2/2]

void ACE_Message_Block::msg_deadline_time ( const ACE_Time_Value & dt )

inline

Set absolute time of deadline associated with the message.

msg_execution_time() [1/2]

const ACE_Time_Value & ACE_Message_Block::msg_execution_time ( ) const

inline

Get execution time associated with the message.

msg_execution_time() [2/2]

void ACE_Message_Block::msg_execution_time ( const ACE_Time_Value & et )

inline

Set execution time associated with the message.

msg_priority() [1/2]

unsigned long ACE_Message_Block::msg_priority ( ) const

inline

Get priority of the message.

msg_priority() [2/2]

void ACE_Message_Block::msg_priority ( unsigned long priority )

inline

Set priority of the message.

msg_type() [1/2]

ACE_Message_Block::ACE_Message_Type ACE_Message_Block::msg_type ( ) const

inline

Get type of the message.

msg_type() [2/2]

void ACE_Message_Block::msg_type ( ACE_Message_Block::ACE_Message_Type t )

inline

Set type of the message.

next() [1/2]

ACE_Message_Block * ACE_Message_Block::next ( ) const

inline

Get link to next message.

next() [2/2]

void ACE_Message_Block::next ( ACE_Message_Block * next_msg )

inline

Set link to next message.

operator=()

ACE_Message_Block & ACE_Message_Block::operator= ( const ACE_Message_Block & )

private

Declare the dynamic allocation hooks.

prev() [1/2]

ACE_Message_Block * ACE_Message_Block::prev ( ) const

inline

Get link to prev message.

prev() [2/2]

void ACE_Message_Block::prev ( ACE_Message_Block * next_msg )

inline

Set link to prev message.

rd_ptr() [1/3]

char * ACE_Message_Block::rd_ptr ( ) const

inline

Get the read pointer.

rd_ptr() [2/3]

void ACE_Message_Block::rd_ptr ( char * ptr )

inline

Set the read pointer to ptr.

rd_ptr() [3/3]

void ACE_Message_Block::rd_ptr ( size_t n )

inline

Set the read pointer ahead n bytes.

reference_count()

int ACE_Message_Block::reference_count ( ) const

inline

Get the current reference count.

release() [1/2]

ACE_Message_Block * ACE_Message_Block::release ( )

virtual

Decrease the shared ACE_Data_Block's reference count by 1. If the ACE_Data_Block's reference count goes to 0, it is deleted. In all cases, this ACE_Message_Block is deleted - it must have come from the heap, or there will be trouble.

release() is designed to release the continuation chain; the destructor is not. If we make the destructor release the continuation chain by calling release() or delete on the message blocks in the continuation chain, the following code will not work since the message block in the continuation chain is not off the heap:

ACE_Message_Block mb1 (1024); ACE_Message_Block mb2 (1024);

mb1.cont (&mb2);

And hence, call release() on a dynamically allocated message block. This will release all the message blocks in the continuation chain. If you call delete or let the message block fall off the stack, cleanup of the message blocks in the continuation chain becomes the responsibility of the user.

Return values

0,always,and

the object this method was invoked on is no longer valid.

release() [2/2]

ACE_Message_Block * ACE_Message_Block::release ( ACE_Message_Block * mb )

static

This behaves like the non-static method release(), except that it checks if mb is 0. This is similar to CORBA::release(), which is useful if you want to eliminate lots of checks for NULL pointers before calling release() on them. Returns mb.

release_i()

int ACE_Message_Block::release_i ( ACE_Lock * lock )

protected

Internal release implementation Returns 1 if the data block has to be destroyed.

replace_data_block()

ACE_Data_Block * ACE_Message_Block::replace_data_block ( ACE_Data_Block * db )

inline

Set a new data block pointer. A pointer to the original ACE_Data_Block is returned, and not released (as it is with <data_block>).

reset()

void ACE_Message_Block::reset ( )

inline

Resets the Message Block data to contain nothing, i.e., sets the read and write pointers to align with the base.

reset_allocators()

void ACE_Message_Block::reset_allocators ( ACE_Allocator * allocator_strategy = 0, ACE_Allocator * data_block_allocator = 0, ACE_Allocator * message_block_allocator = 0 )

inline

Reset all the allocators in the message block.

Todo

Not sure whether we would need finer control while trying to reset allocators ie. a method for every allocator.

This method resets the allocators in all the message blocks in the chain.

self_flags()

ACE_Message_Block::Message_Flags ACE_Message_Block::self_flags ( ) const

inline

Get the current message flags.

set_flags()

ACE_Message_Block::Message_Flags ACE_Message_Block::set_flags ( ACE_Message_Block::Message_Flags more_flags )

inline

Bitwise-or the more_flags into the existing message flags and return the new value.

set_self_flags()

ACE_Message_Block::Message_Flags ACE_Message_Block::set_self_flags ( ACE_Message_Block::Message_Flags more_flags )

inline

Bitwise-or the more_flags into the existing message flags and return the new value.

Todo

I think the following set of methods could not be used at all. May be they are useless. Let us have it so that we don't mess up memory management of the Message_Block. Somebody correct me if I am totally totally wrong..

size() [1/2]

size_t ACE_Message_Block::size ( ) const

inline

Get the number of bytes in the top-level Message_Block (i.e., does not consider the bytes in chained Message_Blocks).

size() [2/2]

int ACE_Message_Block::size

(

size_t

length

)

Set the number of bytes in the top-level Message_Block, reallocating space if necessary. However, the rd_ptr_ and wr_ptr_ remain at the original offsets into the buffer, even if it is reallocated. Returns 0 if successful, else -1.

space()

size_t ACE_Message_Block::space ( ) const

inline

Get the number of bytes available after the <wr_ptr_> in the top-level Message_Block.

total_capacity()

size_t ACE_Message_Block::total_capacity

(

)

const

Get the number of allocated bytes in all Message_Block, including chained Message_Blocks.

total_length()

size_t ACE_Message_Block::total_length

(

)

const

Get the length of the Message_Blocks, including chained Message_Blocks.

total_size()

size_t ACE_Message_Block::total_size

(

)

const

Get the total number of bytes in all Message_Blocks, including chained Message_Blocks.

total_size_and_length()

void ACE_Message_Block::total_size_and_length	(	size_t &	mb_size,
		size_t &	mb_length ) const

Get the total number of bytes and total length in all Message_Blocks, including chained Message_Blocks.

wr_ptr() [1/3]

char * ACE_Message_Block::wr_ptr ( ) const

inline

Get the write pointer.

wr_ptr() [2/3]

void ACE_Message_Block::wr_ptr ( char * ptr )

inline

Set the write pointer to ptr.

wr_ptr() [3/3]

void ACE_Message_Block::wr_ptr ( size_t n )

inline

Set the write pointer ahead n bytes. This is used to compute the <length> of a message.

Friends And Related Symbol Documentation

ACE_Data_Block

friend class ACE_Data_Block

friend

Member Data Documentation

ACE_ALLOC_HOOK_DECLARE

ACE_Message_Block::ACE_ALLOC_HOOK_DECLARE

Declare the dynamic allocation hooks.

cont_

ACE_Message_Block* ACE_Message_Block::cont_

protected

Pointer to next message block in the chain.

data_block_

ACE_Data_Block* ACE_Message_Block::data_block_

protected

Pointer to the reference counted data structure that contains the actual memory buffer.

flags_

ACE_Message_Block::Message_Flags ACE_Message_Block::flags_

protected

Misc flags (e.g., DONT_DELETE and USER_FLAGS).

message_block_allocator_

ACE_Allocator* ACE_Message_Block::message_block_allocator_

protected

The allocator used to destroy ourselves when release is called and create new message blocks on duplicate.

next_

ACE_Message_Block* ACE_Message_Block::next_

protected

Pointer to next message in the list.

prev_

ACE_Message_Block* ACE_Message_Block::prev_

protected

Pointer to previous message in the list.

priority_

unsigned long ACE_Message_Block::priority_

protected

Priority of message.

rd_ptr_

size_t ACE_Message_Block::rd_ptr_

protected

Pointer to beginning of next read.

wr_ptr_

size_t ACE_Message_Block::wr_ptr_

protected

Pointer to beginning of next write.

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

• Message_Block.h
• Message_Block.cpp
• Message_Block.inl