FifoDescriptor Class Reference

Abstraction of a fifo (AKA "named pipe") descriptor. More...

#include <FifoDescriptor.hpp>

Inheritance diagram for FifoDescriptor:

Public Member Functions
	FifoDescriptor (const std::string &name, const int flags)
	Constructor for descriptors of fifos.
	FifoDescriptor (const std::string &name, const int flags, const mode_t mode)
	Constructor for descriptors of fifos.
int	getCapacity ()
	Method to get the capacity of the fifo.
Public Member Functions inherited from PosixDescriptor
virtual	~PosixDescriptor ()
	Destructor.
void	async_read (void(*handler)(Buffer *b, size_t size), Buffer *b, size_t size)
	Run asynchronous read operation.
void	async_read (void(*handler)(void *b, size_t size), void *b, size_t size)
	Run asynchronous read operation.
void	async_write (void(*handler)(Buffer *b, size_t size), Buffer *b, size_t size)
	Run asynchronous write operation.
void	async_write (void(*handler)(void *b, size_t size), void *b, size_t size)
	Run asynchronous write operation.
int	read (Buffer *b, size_t size)
	Method to read from the descriptor and fill a buffer.
int	read (void *p, size_t size)
	Method to read from the descriptor.
int	write (Buffer *b, size_t size)
	Method to write data in a buffer to the descriptor.
int	write (const void *p, size_t size)
	Method to write to the descriptor.
int	write (const std::string &s)
	Method to write a string to the descriptor.
virtual void	close ()
	Method to close the descriptor.
int	getDescriptorNumber () const
	Method to get descriptor number.
	PosixDescriptor (const PosixDescriptor &src)
	Copy constructor.
PosixDescriptor &	operator= (const PosixDescriptor &src)
	Assignment operator.
bool	flush ()
	Method to flush this specific descriptor.
int	ioctl (int request)
	Ioctl on the file descriptor.
int	ioctl (int request, void *argp)
	Ioctl on the file descriptor.

Additional Inherited Members
Protected Member Functions inherited from PosixDescriptor
int	do_read (void *p, size_t size)
	Low-level read.
int	do_write (const void *p, size_t size)
	Low-level write.
	PosixDescriptor ()
	Constructor.
Protected Attributes inherited from PosixDescriptor
int	fd_
	Number of the file descriptor.

Detailed Description

Abstraction of a fifo (AKA "named pipe") descriptor.

This is an abstract class for the concept of fifo. The descriptor corresponds to an open fifo.

Example of usage:

FifoDescriptor fd ("/tmp/myfifo", O_RDONLY);
Buffer b (10);
fd.read (b, b.getSize());

Definition at line 41 of file FifoDescriptor.hpp.

Constructor & Destructor Documentation

FifoDescriptor	(	const std::string &	name,
		const int	flags
	)

Constructor for descriptors of fifos.

It calls open() with the given flags.

Parameters

name	of the fifo
flags	that can be O_RDONLY O_WRONLY or O_RDWR or-ed with zero or more flags: O_APPEND O_ASYNC O_CREAT O_NONBLOCK O_SYNC

Exceptions

runtime_error

if the ::open() returns an error

Definition at line 49 of file FifoDescriptor.cpp.

{
        DEBUG("Opening fifo...");
        fd_ = open(name.c_str(), flags);
        if (fd_ <= 0) {
                ERROR("Opening fifo " << name);
                throw std::runtime_error ("Open fifo error");
        }
}

FifoDescriptor	(	const std::string &	name,
		const int	flags,
		const mode_t	mode
	)

Constructor for descriptors of fifos.

It calls open() with the given flags.

Parameters

name	of the file
flags	that can be O_RDONLY O_WRONLY or O_RDWR or-ed with zero or more flags: O_APPEND O_ASYNC O_CREAT O_NONBLOCK O_SYNC
mode	can be S_IRWXU 00700 user (file owner) has read, write and execute permission S_IRUSR 00400 user has read permission S_IWUSR 00200 user has write permission S_IXUSR 00100 user has execute permission S_IRWXG 00070 group has read, write and execute permission S_IRGRP 00040 group has read permission S_IWGRP 00020 group has write permission S_IXGRP 00010 group has execute permission S_IRWXO 00007 others have read, write and execute permission S_IROTH 00004 others have read permission S_IWOTH 00002 others have write permission S_IXOTH 00001 others have execute permission

Exceptions

runtime_error

if the ::open() returns an error

Definition at line 96 of file FifoDescriptor.cpp.

{
                fd_ = open(name.c_str(), flags, mode);
                if (fd_ <= 0) {
                        ERROR("Opening fifo " << name);
                        throw std::runtime_error ("Open fifo error");
                }
}

Member Function Documentation

int getCapacity

(

)

Method to get the capacity of the fifo.

Returns

length of data available on the file; -1 in case of error or unlimited capacity

Exceptions

runtime_error

in case it's not possible to get the capacity

Definition at line 115 of file FifoDescriptor.cpp.

{
        long int v;
        errno = 0;
        if ((v = fpathconf(fd_,_PC_PIPE_BUF)) == -1)
                if (errno != 0) {
                        ERROR("Can't get fifo capacity");
                        throw std::runtime_error ("Fifo capacity error");
                        return -1;
                }
        return v;
}

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

• /home/cloud/work/onposix-code/include/FifoDescriptor.hpp
• /home/cloud/work/onposix-code/src/FifoDescriptor.cpp