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ACE_Asynch_Read_File Class Reference

This class is a factory for starting off asynchronous reads on a file. This class forwards all methods to its implementation class. More...

#include <Asynch_IO.h>

Inheritance diagram for ACE_Asynch_Read_File:

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List of all members.

Public Methods

 ACE_Asynch_Read_File (void)
 A do nothing constructor. More...

virtual ~ACE_Asynch_Read_File (void)
 Destructor. More...

int open (ACE_Handler &handler, ACE_HANDLE handle=ACE_INVALID_HANDLE, const void *completion_key=0, ACE_Proactor *proactor=0)
int read (ACE_Message_Block &message_block, size_t bytes_to_read, u_long offset=0, u_long offset_high=0, const void *act=0, int priority=0, int signal_number=ACE_SIGRTMIN)
int readv (ACE_Message_Block &message_block, size_t bytes_to_read, u_long offset=0, u_long offset_high=0, const void *act=0, int priority=0, int signal_number=ACE_SIGRTMIN)
ACE_Asynch_Read_File_Implimplementation (void) const
 Return the underlying implementation class. More...


Protected Methods

void implementation (ACE_Asynch_Read_File_Impl *implementation)
 Set the implementation class. More...


Protected Attributes

ACE_Asynch_Read_File_Implimplementation_
 Delegation/implementation class that all methods will be forwarded to. More...


Detailed Description

This class is a factory for starting off asynchronous reads on a file. This class forwards all methods to its implementation class.

Once <open> is called, multiple asynchronous <read>s can started using this class. An ACE_Asynch_Read_File::Result will be passed back to the <handler> when the asynchronous reads completes through the <ACE_Handler::handle_read_file> callback. This class differs slightly from ACE_Asynch_Read_Stream as it allows the user to specify an offset for the read.

Definition at line 510 of file Asynch_IO.h.


Constructor & Destructor Documentation

ACE_Asynch_Read_File::ACE_Asynch_Read_File void   
 

A do nothing constructor.

Definition at line 402 of file Asynch_IO.cpp.

References ACE_Asynch_Write_Stream::implementation_.

00403   : implementation_ (0)
00404 {
00405 } 

ACE_Asynch_Read_File::~ACE_Asynch_Read_File void    [virtual]
 

Destructor.

Definition at line 407 of file Asynch_IO.cpp.

00408 {
00409 } 


Member Function Documentation

void ACE_Asynch_Read_File::implementation ACE_Asynch_Read_File_Impl   implementation [protected]
 

Set the implementation class.

Definition at line 484 of file Asynch_IO.cpp.

References ACE_Asynch_Read_Stream::implementation, and implementation_.

00485 {
00486   this->implementation_ = implementation;
00487 
00488   // Set also the base class' implementation.
00489   ACE_Asynch_Read_Stream::implementation (implementation);
00490 }

ACE_Asynch_Read_File_Impl * ACE_Asynch_Read_File::implementation void    const
 

Return the underlying implementation class.

Reimplemented from ACE_Asynch_Read_Stream.

Definition at line 478 of file Asynch_IO.cpp.

References implementation_.

Referenced by open, read, and readv.

00479 {
00480   return this->implementation_;
00481 }

int ACE_Asynch_Read_File::open ACE_Handler   handler,
ACE_HANDLE    handle = ACE_INVALID_HANDLE,
const void *    completion_key = 0,
ACE_Proactor   proactor = 0
 

Initializes the factory with information which will be used with each asynchronous call. If (<handle> == ACE_INVALID_HANDLE), <ACE_Handler::handle> will be called on the <handler> to get the correct handle.

Reimplemented from ACE_Asynch_Read_Stream.

Definition at line 412 of file Asynch_IO.cpp.

References ACE_Proactor::create_asynch_read_file, ACE_Asynch_Operation::get_proactor, implementation, implementation_, and ACE_Asynch_Operation::open.

00416 {
00417   // Get a proactor for/from the user.
00418   proactor = this->get_proactor (proactor, handler);
00419 
00420   // Delete the old implementation.
00421   delete this->implementation_;
00422   this->implementation_ = 0;
00423 
00424   // Now let us get the implementation initialized.
00425   ACE_Asynch_Read_File_Impl *implementation = proactor->create_asynch_read_file ();
00426   if (implementation == 0)
00427     return -1;
00428   
00429   // Set the implementation class
00430   this->implementation (implementation);
00431   
00432   // Call the <open> method of the base class.
00433   return ACE_Asynch_Operation::open (handler,
00434                                      handle,
00435                                      completion_key,
00436                                      proactor);
00437 }

int ACE_Asynch_Read_File::read ACE_Message_Block   message_block,
size_t    bytes_to_read,
u_long    offset = 0,
u_long    offset_high = 0,
const void *    act = 0,
int    priority = 0,
int    signal_number = ACE_SIGRTMIN
 

This starts off an asynchronous read. Upto <bytes_to_read> will be read and stored in the <message_block>. The read will start at <offset> from the beginning of the file. Priority of the operation is specified by <priority>. On POSIX4-Unix, this is supported. Works like <nice> in Unix. Negative values are not allowed. 0 means priority of the operation same as the process priority. 1 means priority of the operation is one less than process. And so forth. On Win32, this argument is a no-op. <signal_number> is the POSIX4 real-time signal number to be used for the operation. <signal_number> ranges from ACE_SIGRTMIN to ACE_SIGRTMAX. This argument is a no-op on non-POSIX4 systems.

Definition at line 440 of file Asynch_IO.cpp.

References implementation, and ACE_Asynch_Read_File_Impl::read.

00447 {
00448   return this->implementation ()->read (message_block,
00449                                         bytes_to_read,
00450                                         offset,
00451                                         offset_high,
00452                                         act,
00453                                         priority,
00454                                         signal_number);
00455 }

int ACE_Asynch_Read_File::readv ACE_Message_Block   message_block,
size_t    bytes_to_read,
u_long    offset = 0,
u_long    offset_high = 0,
const void *    act = 0,
int    priority = 0,
int    signal_number = ACE_SIGRTMIN
 

Same as above but with scatter support, through chaining of composite message blocks using the continuation field. NOTE: In win32 Each data block payload must be at least the size of a system memory page and must be aligned on a system memory page size boundary

Definition at line 459 of file Asynch_IO.cpp.

References implementation, and ACE_Asynch_Read_File_Impl::readv.

00466 {
00467   return this->implementation ()->readv (message_block,
00468                                          bytes_to_read,
00469                                          offset,
00470                                          offset_high,
00471                                          act,
00472                                          priority,
00473                                          signal_number);
00474 }


Member Data Documentation

ACE_Asynch_Read_File_Impl* ACE_Asynch_Read_File::implementation_ [protected]
 

Delegation/implementation class that all methods will be forwarded to.

Reimplemented from ACE_Asynch_Read_Stream.

Definition at line 577 of file Asynch_IO.h.

Referenced by ACE_Asynch_Write_File::ACE_Asynch_Write_File, implementation, and open.


The documentation for this class was generated from the following files:
Generated on Mon Jun 16 12:45:23 2003 for ACE by doxygen1.2.14 written by Dimitri van Heesch, © 1997-2002