ola::io Namespace Reference

Detailed Description

Classes for general I/O and event handling.

Classes
class	BidirectionalFileDescriptor
	A file descriptor that supports both read & write. More...
class	BigEndianInputStream
class	BigEndianInputStreamAdaptor
class	BigEndianInputStreamInterface
class	BigEndianOutputStream
class	BigEndianOutputStreamAdaptor
class	BigEndianOutputStreamInterface
class	ConnectedDescriptor
	A BidirectionalFileDescriptor that also generates notifications when closed. More...
class	DeviceDescriptor
	A descriptor which represents a connection to a device. More...
class	EPollData
class	EPoller
	An implementation of PollerInterface that uses epoll(). More...
class	EventHolder
class	InputBufferInterface
class	InputStream
class	InputStreamInterface
class	IOQueue
class	IOStack
struct	IOVec
class	IOVecInterface
class	KQueueData
class	KQueuePoller
	An implementation of PollerInterface that uses kevent / kqueue. More...
class	LinuxHelper
	A static class containing platform-specific helper code for Linux. More...
class	LoopbackDescriptor
	A loopback descriptor. More...
class	MemoryBlock
	A MemoryBlock encapsulates a chunk of memory. It's used by the IOQueue and IOStack classes. More...
class	MemoryBlockPool
	MemoryBlockPool. This class is not thread safe. More...
class	MemoryBuffer
class	NonBlockingSender
	Write data to ConnectedDescriptors without blocking or losing data. More...
class	OutputBufferInterface
class	OutputStream
class	OutputStreamInterface
class	PipeDescriptor
	A descriptor that uses unix pipes. More...
class	PollData
class	PollerInterface
	The interface for the Poller classes. More...
class	ReadFileDescriptor
	Represents a file descriptor that supports reading data. More...
class	SelectPoller
	An implementation of PollerInterface that uses select(). More...
class	SelectServer
	A single threaded I/O event management system. More...
class	SelectServerInterface
	The interface for the SelectServer. More...
class	StdinHandler
class	TimeoutManager
	Manages timer events. More...
class	UnixSocket
	A unix domain socket pair. More...
class	UnmanagedFileDescriptor
	Allows a FD created by a library to be used with the SelectServer. More...
struct	UnmanagedFileDescriptor_lt
	Comparison operator for UnmanagedFileDescriptor. More...
class	WindowsPoller
	An implementation of PollerInterface for Windows. More...
class	WindowsPollerDescriptor
class	WriteFileDescriptor
	Represents a file descriptor that supports writing data. More...

Typedefs
typedef std::basic_string< uint8_t >	ByteString
	A contiguous block of uint8_t data. More...
typedef int	DescriptorHandle

Enumerations
enum	baud_rate {   BAUD_RATE_9600 = 9600, BAUD_RATE_19200 = 19200, BAUD_RATE_38400 = 38400, BAUD_RATE_57600 = 57600,   BAUD_RATE_115200 = 115200, BAUD_RATE_230400 = 230400 }

Functions
	STATIC_ASSERT (sizeof(struct iovec)==sizeof(struct IOVec))
int	ToFD (const DescriptorHandle &handle)
bool	CreatePipe (DescriptorHandle handle_pair[2])
bool	Open (const std::string &path, int oflag, int *fd)
	Wrapper around open(). More...
bool	TryOpen (const std::string &path, int oflag, int *fd)
	Wrapper around open(). More...
bool	FileExists (const std::string &file_name)
	Check if a file exists using stat(). More...
template<typename T >
bool	InsertIntoDescriptorMap (map< int, T *> *descriptor_map, int fd, T *value, const string &type)
	Insert a descriptor into one of the descriptor maps. More...
template<typename T >
bool	RemoveFromDescriptorMap (map< int, T *> *descriptor_map, int fd)
	Remove a FD from a descriptor map by setting the value to NULL. More...
bool	UIntToSpeedT (uint32_t value, speed_t *output)
	Convert an integer baud rate to the termios struct speed_t. More...
bool	AcquireUUCPLockAndOpen (const std::string &path, int oflag, int *fd)
	Try to open the path, respecting UUCP locking. More...
void	ReleaseUUCPLock (const std::string &path)
	Remove a UUCP lock file for the device. More...
void	CancelIOs (vector< PollData *> *data)

Variables
static const int	FLAG_READ = 1
static const int	FLAG_WRITE = 2
static DescriptorHandle	INVALID_DESCRIPTOR = -1

Typedef Documentation

ByteString

typedef std::basic_string<uint8_t> ola::io::ByteString

A contiguous block of uint8_t data.

The constraints of the .data() and .c_str() methods from the C++ standard mean that string stores it's data in a contiguous block.

In some implementations, basic_string may be reference counted, but with the additional constraints added by C++11 this will not be the case, so think twice about copying ByteStrings.

Function Documentation

AcquireUUCPLockAndOpen()

bool ola::io::AcquireUUCPLockAndOpen	(	const std::string &	path,
		int	oflag,
		int *	fd
	)

Try to open the path, respecting UUCP locking.

Parameters

	path	the path to open
	oflag	flags passed to open
[out]	fd	a pointer to the fd which is returned.

Returns

true if the open succeeded, false otherwise.

This fails-fast, it we can't get the lock immediately, we'll return false.

CreatePipe()

bool ola::io::CreatePipe

(

DescriptorHandle

handle_pair[2]

)

Helper function to create a anonymous pipe

Parameters

handle_pair

a 2 element array which is updated with the handles

Returns

true if successful, false otherwise.

FileExists()

bool ola::io::FileExists

(

const std::string &

file_name

)

Check if a file exists using stat().

Parameters

file_name

The name of the file.

Returns

true if the stat() command completed & the file exists, false if stat() failed, or the file doesn't exist.

InsertIntoDescriptorMap()

template<typename T >

bool ola::io::InsertIntoDescriptorMap	(	map< int, T *> *	descriptor_map,
		int	fd,
		T *	value,
		const string &	type
	)

Insert a descriptor into one of the descriptor maps.

Parameters

descriptor_map	the descriptor_map to insert into.
fd	the FD to use as the key
value	the value to associate with the key
type	the name of the map, used for logging if the fd already exists in the map.

Returns

true if the descriptor was inserted, false if it was already in the map.

There are three possibilities:

• The fd does not already exist in the map
• The fd exists and the value is NULL.
• The fd exists and is not NULL.

Open()

bool ola::io::Open	(	const std::string &	path,
		int	oflag,
		int *	fd
	)

Wrapper around open().

This logs a message if the open fails.

Parameters

	path	the path to open
	oflag	flags passed to open
[out]	fd	a pointer to the fd which is returned.

Returns

true if the open succeeded, false otherwise.

ReleaseUUCPLock()

void ola::io::ReleaseUUCPLock

(

const std::string &

path

)

Remove a UUCP lock file for the device.

Parameters

path	The path to unlock.

The lock is only removed if the PID matches.

RemoveFromDescriptorMap()

template<typename T >

bool ola::io::RemoveFromDescriptorMap	(	map< int, T *> *	descriptor_map,
		int	fd
	)

Remove a FD from a descriptor map by setting the value to NULL.

Returns

true if the FD was removed from the map, false if it didn't exist in the map.

TryOpen()

bool ola::io::TryOpen	(	const std::string &	path,
		int	oflag,
		int *	fd
	)

Wrapper around open().

This is similar to Open(), but doesn't log a warning if open() fails.

Parameters

	path	the path to open
	oflag	flags passed to open
[out]	fd	a pointer to the fd which is returned.

Returns

true if the open succeeded, false otherwise.

See also

Open

UIntToSpeedT()

bool ola::io::UIntToSpeedT	(	uint32_t	value,
		speed_t *	output
	)

Convert an integer baud rate to the termios struct speed_t.

Parameters

[in]	value	the baudrate value to convert
[out]	output	a pointer where the value will be stored

Returns

true if the value was converted, false if the baud rate wasn't supported by the method.