DeviceReadBuffer Class Reference

Buffers reads from device files. More...

#include <libmythtv/recorders/DeviceReadBuffer.h>

Inheritance diagram for DeviceReadBuffer:

Collaboration diagram for DeviceReadBuffer:

Public Member Functions
	DeviceReadBuffer (DeviceReaderCB *cb, bool use_poll=true, bool error_exit_on_poll_timeout=true)
	~DeviceReadBuffer () override
bool	Setup (const QString &streamName, int streamfd, uint readQuanta=sizeof(TSPacket), uint deviceBufferSize=0, uint deviceBufferCount=1)
void	Start (void)
void	Reset (const QString &streamName, int streamfd)
void	Stop (void)
void	SetRequestPause (bool request)
bool	IsPaused (void) const
bool	WaitForUnpause (unsigned long timeout)
bool	WaitForPaused (unsigned long timeout)
bool	IsErrored (void) const
bool	IsEOF (void) const
bool	IsRunning (void) const
uint	Read (unsigned char *buf, uint count)
	Try to Read count bytes from into buffer. More...
uint	GetUsed (void) const

Protected Member Functions
void	run (void) override
	Runs the Qt event loop unless we have a QRunnable, in which case we run the runnable run instead. More...
Protected Member Functions inherited from MThread
virtual void	run (void)
	Runs the Qt event loop unless we have a QRunnable, in which case we run the runnable run instead. More...
int	exec (void)
	Enters the qt event loop. call exit or quit to exit thread. More...
	MThread (const QString &objectName)
	Standard constructor. More...
	MThread (const QString &objectName, QRunnable *runnable)
	Use this constructor if you want the default run() method to run the QRunnable's run() method instead of entering the Qt event loop. More...
virtual	~MThread ()
	MThread (const MThread &)=delete
MThread &	operator= (const MThread &)=delete
void	RunProlog (void)
	Sets up a thread, call this if you reimplement run(). More...
void	RunEpilog (void)
	Cleans up a thread's resources, call this if you reimplement run(). More...
QThread *	qthread (void)
	Returns the thread, this will always return the same pointer no matter how often you restart the thread. More...
void	setObjectName (const QString &name)
QString	objectName (void) const
void	setPriority (QThread::Priority priority)
QThread::Priority	priority (void) const
bool	isFinished (void) const
bool	isRunning (void) const
void	setStackSize (uint stackSize)
uint	stackSize (void) const
void	exit (int retcode=0)
	Use this to exit from the thread if you are using a Qt event loop. More...
void	start (QThread::Priority p=QThread::InheritPriority)
	Tell MThread to start running the thread in the near future. More...
void	terminate (void)
	Kill a thread unsafely. More...
void	quit (void)
	calls exit(0) More...
bool	wait (std::chrono::milliseconds time=std::chrono::milliseconds::max())
	Wait for the MThread to exit, with a maximum timeout. More...

Private Types
using	pipe_fd_array = std::array< int, 2 >
using	pipe_flag_array = std::array< long, 2 >

Private Member Functions
void	SetPaused (bool val)
void	IncrWritePointer (uint len)
void	IncrReadPointer (uint len)
bool	HandlePausing (void)
bool	Poll (void) const
void	WakePoll (void) const
uint	WaitForUnused (uint needed) const
uint	WaitForUsed (uint needed, std::chrono::milliseconds max_wait) const
bool	IsPauseRequested (void) const
bool	IsOpen (void) const
void	ClosePipes (void) const
uint	GetUnused (void) const
uint	GetContiguousUnused (void) const
bool	CheckForErrors (ssize_t read_len, size_t requested_len, uint &errcnt)
void	ReportStats (void)

Static Private Member Functions
static void	setup_pipe (pipe_fd_array &mypipe, pipe_flag_array &myflags)

Private Attributes
QString	m_videoDevice
int	m_streamFd {-1}
pipe_fd_array	m_wakePipe {-1,-1}
pipe_flag_array	m_wakePipeFlags {0,0}
DeviceReaderCB *	m_readerCB {nullptr}
QMutex	m_lock
volatile bool	m_doRun {false}
bool	m_eof {false}
bool	m_error {false}
bool	m_requestPause {false}
bool	m_paused {false}
bool	m_usingPoll {true}
bool	m_pollTimeoutIsError {true}
std::chrono::milliseconds	m_maxPollWait {2500ms}
size_t	m_size {0}
size_t	m_used {0}
size_t	m_readQuanta {0}
size_t	m_devBufferCount {1}
size_t	m_devReadSize {0}
size_t	m_readThreshold {0}
unsigned char *	m_buffer {nullptr}
unsigned char *	m_readPtr {nullptr}
unsigned char *	m_writePtr {nullptr}
unsigned char *	m_endPtr {nullptr}
QWaitCondition	m_dataWait
QWaitCondition	m_runWait
QWaitCondition	m_pauseWait
QWaitCondition	m_unpauseWait
size_t	m_maxUsed {0}
size_t	m_avgUsed {0}
size_t	m_avgBufWriteCnt {0}
size_t	m_avgBufReadCnt {0}
size_t	m_avgBufSleepCnt {0}
MythTimer	m_lastReport

Additional Inherited Members
Static Protected Member Functions inherited from MThread
static void	setTerminationEnabled (bool enabled=true)
static void	ThreadSetup (const QString &name)
	This is to be called on startup in those few threads that haven't been ported to MThread. More...
static void	ThreadCleanup (void)
	This is to be called on exit in those few threads that haven't been ported to MThread. More...
static void	Cleanup (void)
	This will print out all the running threads, call exit(1) on each and then wait up to 5 seconds total for all the threads to exit. More...
static void	GetAllThreadNames (QStringList &list)
static void	GetAllRunningThreadNames (QStringList &list)
Protected Attributes inherited from MThread
MThreadInternal *	m_thread {nullptr}
QRunnable *	m_runnable {nullptr}
bool	m_prologExecuted {true}
bool	m_epilogExecuted {true}

Detailed Description

Buffers reads from device files.

This allows us to read the device regularly even in the presence of long blocking conditions on writing to disk or accessing the database.

Definition at line 35 of file DeviceReadBuffer.h.

Member Typedef Documentation

pipe_fd_array

using DeviceReadBuffer::pipe_fd_array = std::array<int,2>

private

Definition at line 88 of file DeviceReadBuffer.h.

pipe_flag_array

using DeviceReadBuffer::pipe_flag_array = std::array<long,2>

private

Definition at line 89 of file DeviceReadBuffer.h.

Constructor & Destructor Documentation

DeviceReadBuffer()

DeviceReadBuffer::DeviceReadBuffer ( DeviceReaderCB *  cb, bool  use_poll = true, bool  error_exit_on_poll_timeout = true  )

explicit

Definition at line 72 of file DeviceReadBuffer.cpp.

~DeviceReadBuffer()

DeviceReadBuffer::~DeviceReadBuffer ( )

override

Definition at line 90 of file DeviceReadBuffer.cpp.

Member Function Documentation

CheckForErrors()

bool DeviceReadBuffer::CheckForErrors ( ssize_t  read_len, size_t  requested_len, uint &  errcnt  )

private

Definition at line 587 of file DeviceReadBuffer.cpp.

Referenced by run().

ClosePipes()

void DeviceReadBuffer::ClosePipes ( void  ) const

private

Definition at line 253 of file DeviceReadBuffer.cpp.

Referenced by run(), and WakePoll().

GetContiguousUnused()

uint DeviceReadBuffer::GetContiguousUnused ( void  ) const

private

Definition at line 328 of file DeviceReadBuffer.cpp.

GetUnused()

uint DeviceReadBuffer::GetUnused ( void  ) const

private

Definition at line 316 of file DeviceReadBuffer.cpp.

Referenced by WaitForUnused().

GetUsed()

uint DeviceReadBuffer::GetUsed

(

void

)

const

Definition at line 322 of file DeviceReadBuffer.cpp.

Referenced by V4L2encStreamHandler::AvailCount().

HandlePausing()

bool DeviceReadBuffer::HandlePausing ( void  )

private

Definition at line 445 of file DeviceReadBuffer.cpp.

Referenced by run().

IncrReadPointer()

void DeviceReadBuffer::IncrReadPointer ( uint  len )

private

Definition at line 348 of file DeviceReadBuffer.cpp.

Referenced by Read().

IncrWritePointer()

void DeviceReadBuffer::IncrWritePointer ( uint  len )

private

Definition at line 334 of file DeviceReadBuffer.cpp.

Referenced by run().

IsEOF()

bool DeviceReadBuffer::IsEOF

(

void

)

const

Definition at line 304 of file DeviceReadBuffer.cpp.

Referenced by MpegRecorder::run(), V4L2encStreamHandler::run(), and DVBStreamHandler::RunTS().

IsErrored()

bool DeviceReadBuffer::IsErrored

(

void

)

const

Definition at line 298 of file DeviceReadBuffer.cpp.

Referenced by MpegRecorder::run(), V4L2encStreamHandler::run(), and DVBStreamHandler::RunTS().

IsOpen()

bool DeviceReadBuffer::IsOpen ( void  ) const

inlineprivate

Definition at line 80 of file DeviceReadBuffer.h.

Referenced by Poll(), run(), and WaitForUnused().

IsPaused()

bool DeviceReadBuffer::IsPaused

(

void

)

const

Definition at line 266 of file DeviceReadBuffer.cpp.

Referenced by HandlePausing().

IsPauseRequested()

bool DeviceReadBuffer::IsPauseRequested ( void  ) const

private

Definition at line 292 of file DeviceReadBuffer.cpp.

Referenced by HandlePausing(), Poll(), and WaitForUnused().

IsRunning()

bool DeviceReadBuffer::IsRunning

(

void

)

const

Definition at line 310 of file DeviceReadBuffer.cpp.

Referenced by V4L2encStreamHandler::Open(), MpegRecorder::OpenV4L2DeviceAsInput(), MpegRecorder::StopEncoding(), V4L2encStreamHandler::StopEncoding(), and MpegRecorder::TeardownAll().

Poll()

bool DeviceReadBuffer::Poll ( void  ) const

private

Definition at line 465 of file DeviceReadBuffer.cpp.

Referenced by run().

Read()

uint DeviceReadBuffer::Read	(	unsigned char *	buf,
		uint	count
	)

Try to Read count bytes from into buffer.

Parameters

buf	Buffer to put data in
count	Number of bytes to attempt to read

Returns

number of bytes actually read

Definition at line 664 of file DeviceReadBuffer.cpp.

Referenced by MpegRecorder::run(), V4L2encStreamHandler::run(), and DVBStreamHandler::RunTS().

ReportStats()

void DeviceReadBuffer::ReportStats ( void  )

private

Definition at line 749 of file DeviceReadBuffer.cpp.

Referenced by Read().

Reset()

void DeviceReadBuffer::Reset	(	const QString &	streamName,
		int	streamfd
	)

Definition at line 190 of file DeviceReadBuffer.cpp.

Referenced by HandlePausing(), and MpegRecorder::StartEncoding().

run()

void DeviceReadBuffer::run ( void  )

overrideprotectedvirtual

Runs the Qt event loop unless we have a QRunnable, in which case we run the runnable run instead.

Note

If you override this method you must call RunProlog before you do any work and RunEpilog before you exit the run method.

Reimplemented from MThread.

Definition at line 359 of file DeviceReadBuffer.cpp.

SetPaused()

void DeviceReadBuffer::SetPaused ( bool  val )

private

Definition at line 226 of file DeviceReadBuffer.cpp.

Referenced by HandlePausing().

SetRequestPause()

void DeviceReadBuffer::SetRequestPause

(

bool

request

)

Definition at line 219 of file DeviceReadBuffer.cpp.

Referenced by V4L2encStreamHandler::Open(), MpegRecorder::StartEncoding(), V4L2encStreamHandler::StartEncoding(), MpegRecorder::StopEncoding(), and V4L2encStreamHandler::StopEncoding().

Setup()

bool DeviceReadBuffer::Setup	(	const QString &	streamName,
		int	streamfd,
		uint	readQuanta = sizeof(TSPacket),
		uint	deviceBufferSize = 0,
		uint	deviceBufferCount = 1
	)

Definition at line 100 of file DeviceReadBuffer.cpp.

Referenced by V4L2encStreamHandler::Open(), MpegRecorder::OpenV4L2DeviceAsInput(), and DVBStreamHandler::RunTS().

setup_pipe()

void DeviceReadBuffer::setup_pipe ( pipe_fd_array &  mypipe, pipe_flag_array &  myflags  )

staticprivate

Definition at line 30 of file DeviceReadBuffer.cpp.

Referenced by run().

Start()

void DeviceReadBuffer::Start

(

void

)

Definition at line 162 of file DeviceReadBuffer.cpp.

Referenced by DVBStreamHandler::RunTS(), MpegRecorder::StartEncoding(), and V4L2encStreamHandler::StartEncoding().

Stop()

void DeviceReadBuffer::Stop

(

void

)

Definition at line 205 of file DeviceReadBuffer.cpp.

Referenced by V4L2encStreamHandler::Close(), V4L2encStreamHandler::Open(), MpegRecorder::OpenV4L2DeviceAsInput(), ASIStreamHandler::run(), ASIStreamHandler::SetRunningDesired(), MpegRecorder::StopEncoding(), MpegRecorder::TeardownAll(), and ~DeviceReadBuffer().

WaitForPaused()

bool DeviceReadBuffer::WaitForPaused

(

unsigned long

timeout

)

Definition at line 272 of file DeviceReadBuffer.cpp.

WaitForUnpause()

bool DeviceReadBuffer::WaitForUnpause

(

unsigned long

timeout

)

Definition at line 282 of file DeviceReadBuffer.cpp.

WaitForUnused()

uint DeviceReadBuffer::WaitForUnused ( uint  needed ) const

private

Parameters

needed

Number of bytes we want to write

Returns

bytes available for writing

Definition at line 706 of file DeviceReadBuffer.cpp.

Referenced by run().

WaitForUsed()

uint DeviceReadBuffer::WaitForUsed ( uint  needed, std::chrono::milliseconds  max_wait  ) const

private

Parameters

needed	Number of bytes we want to read
max_wait	Number of milliseconds to wait for the needed data

Returns

bytes available for reading

Definition at line 732 of file DeviceReadBuffer.cpp.

Referenced by Read().

WakePoll()

void DeviceReadBuffer::WakePoll ( void  ) const

private

Definition at line 237 of file DeviceReadBuffer.cpp.

Referenced by SetRequestPause(), Start(), and Stop().

Member Data Documentation

m_avgBufReadCnt

size_t DeviceReadBuffer::m_avgBufReadCnt {0}

private

Definition at line 130 of file DeviceReadBuffer.h.

Referenced by IncrReadPointer(), ReportStats(), and Setup().

m_avgBufSleepCnt

size_t DeviceReadBuffer::m_avgBufSleepCnt {0}

private

Definition at line 131 of file DeviceReadBuffer.h.

Referenced by ReportStats(), and Setup().

m_avgBufWriteCnt

size_t DeviceReadBuffer::m_avgBufWriteCnt {0}

private

Definition at line 129 of file DeviceReadBuffer.h.

Referenced by IncrWritePointer(), ReportStats(), and Setup().

m_avgUsed

size_t DeviceReadBuffer::m_avgUsed {0}

private

Definition at line 128 of file DeviceReadBuffer.h.

Referenced by IncrWritePointer(), ReportStats(), and Setup().

m_buffer

unsigned char* DeviceReadBuffer::m_buffer {nullptr}

private

Definition at line 116 of file DeviceReadBuffer.h.

Referenced by IncrReadPointer(), IncrWritePointer(), Reset(), run(), Setup(), and ~DeviceReadBuffer().

m_dataWait

QWaitCondition DeviceReadBuffer::m_dataWait

mutableprivate

Definition at line 121 of file DeviceReadBuffer.h.

Referenced by IncrWritePointer(), run(), and WaitForUsed().

m_devBufferCount

size_t DeviceReadBuffer::m_devBufferCount {1}

private

Definition at line 113 of file DeviceReadBuffer.h.

Referenced by run(), and Setup().

m_devReadSize

size_t DeviceReadBuffer::m_devReadSize {0}

private

Definition at line 114 of file DeviceReadBuffer.h.

Referenced by run(), and Setup().

m_doRun

volatile bool DeviceReadBuffer::m_doRun {false}

private

Definition at line 101 of file DeviceReadBuffer.h.

Referenced by Poll(), run(), Start(), Stop(), and WaitForUnused().

m_endPtr

unsigned char* DeviceReadBuffer::m_endPtr {nullptr}

private

Definition at line 119 of file DeviceReadBuffer.h.

Referenced by GetContiguousUnused(), IncrReadPointer(), IncrWritePointer(), Read(), run(), and Setup().

m_eof

bool DeviceReadBuffer::m_eof {false}

private

Definition at line 102 of file DeviceReadBuffer.h.

Referenced by CheckForErrors(), IsEOF(), run(), Setup(), Start(), and WaitForUsed().

m_error

bool DeviceReadBuffer::m_error {false}

mutableprivate

Definition at line 103 of file DeviceReadBuffer.h.

Referenced by CheckForErrors(), IsErrored(), Poll(), Reset(), run(), Setup(), Start(), and WaitForUsed().

m_lastReport

MythTimer DeviceReadBuffer::m_lastReport

private

Definition at line 132 of file DeviceReadBuffer.h.

Referenced by ReportStats(), and Setup().

m_lock

QMutex DeviceReadBuffer::m_lock

mutableprivate

Definition at line 100 of file DeviceReadBuffer.h.

Referenced by CheckForErrors(), GetContiguousUnused(), GetUnused(), GetUsed(), IncrReadPointer(), IncrWritePointer(), IsEOF(), IsErrored(), IsPaused(), IsPauseRequested(), IsRunning(), Poll(), ReportStats(), Reset(), run(), SetPaused(), SetRequestPause(), Setup(), Start(), Stop(), WaitForPaused(), WaitForUnpause(), and WaitForUsed().

m_maxPollWait

std::chrono::milliseconds DeviceReadBuffer::m_maxPollWait {2500ms}

private

Definition at line 108 of file DeviceReadBuffer.h.

Referenced by Poll().

m_maxUsed

size_t DeviceReadBuffer::m_maxUsed {0}

private

Definition at line 127 of file DeviceReadBuffer.h.

Referenced by IncrWritePointer(), ReportStats(), and Setup().

m_paused

bool DeviceReadBuffer::m_paused {false}

private

Definition at line 105 of file DeviceReadBuffer.h.

Referenced by IsPaused(), SetPaused(), Setup(), WaitForPaused(), and WaitForUnpause().

m_pauseWait

QWaitCondition DeviceReadBuffer::m_pauseWait

private

Definition at line 123 of file DeviceReadBuffer.h.

Referenced by run(), SetPaused(), and WaitForPaused().

m_pollTimeoutIsError

bool DeviceReadBuffer::m_pollTimeoutIsError {true}

private

Definition at line 107 of file DeviceReadBuffer.h.

Referenced by Poll().

m_readerCB

DeviceReaderCB* DeviceReadBuffer::m_readerCB {nullptr}

private

Definition at line 97 of file DeviceReadBuffer.h.

Referenced by HandlePausing(), and Poll().

m_readPtr

unsigned char* DeviceReadBuffer::m_readPtr {nullptr}

private

Definition at line 117 of file DeviceReadBuffer.h.

Referenced by IncrReadPointer(), Read(), Reset(), and Setup().

m_readQuanta

size_t DeviceReadBuffer::m_readQuanta {0}

private

Definition at line 112 of file DeviceReadBuffer.h.

Referenced by run(), Setup(), and WaitForUnused().

m_readThreshold

size_t DeviceReadBuffer::m_readThreshold {0}

private

Definition at line 115 of file DeviceReadBuffer.h.

Referenced by Read(), and Setup().

m_requestPause

bool DeviceReadBuffer::m_requestPause {false}

private

Definition at line 104 of file DeviceReadBuffer.h.

Referenced by IsPauseRequested(), SetRequestPause(), Setup(), and WaitForUsed().

m_runWait

QWaitCondition DeviceReadBuffer::m_runWait

private

Definition at line 122 of file DeviceReadBuffer.h.

Referenced by run(), and Start().

m_size

size_t DeviceReadBuffer::m_size {0}

private

Definition at line 110 of file DeviceReadBuffer.h.

Referenced by GetUnused(), ReportStats(), and Setup().

m_streamFd

int DeviceReadBuffer::m_streamFd {-1}

private

Definition at line 93 of file DeviceReadBuffer.h.

Referenced by CheckForErrors(), HandlePausing(), IsOpen(), Poll(), Reset(), run(), and Setup().

m_unpauseWait

QWaitCondition DeviceReadBuffer::m_unpauseWait

private

Definition at line 124 of file DeviceReadBuffer.h.

Referenced by run(), SetPaused(), and WaitForUnpause().

m_used

size_t DeviceReadBuffer::m_used {0}

private

Definition at line 111 of file DeviceReadBuffer.h.

Referenced by GetUnused(), GetUsed(), IncrReadPointer(), IncrWritePointer(), Reset(), Setup(), and WaitForUsed().

m_usingPoll

bool DeviceReadBuffer::m_usingPoll {true}

private

Definition at line 106 of file DeviceReadBuffer.h.

Referenced by DeviceReadBuffer(), run(), and Setup().

m_videoDevice

QString DeviceReadBuffer::m_videoDevice

private

Definition at line 92 of file DeviceReadBuffer.h.

Referenced by HandlePausing(), Reset(), and Setup().

m_wakePipe

pipe_fd_array DeviceReadBuffer::m_wakePipe {-1,-1}

mutableprivate

Definition at line 94 of file DeviceReadBuffer.h.

Referenced by ClosePipes(), Poll(), run(), and WakePoll().

m_wakePipeFlags

pipe_flag_array DeviceReadBuffer::m_wakePipeFlags {0,0}

mutableprivate

Definition at line 95 of file DeviceReadBuffer.h.

Referenced by ClosePipes(), Poll(), and run().

m_writePtr

unsigned char* DeviceReadBuffer::m_writePtr {nullptr}

private

Definition at line 118 of file DeviceReadBuffer.h.

Referenced by GetContiguousUnused(), IncrWritePointer(), Reset(), run(), and Setup().

---

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

• mythtv/libs/libmythtv/recorders/DeviceReadBuffer.h
• mythtv/libs/libmythtv/recorders/DeviceReadBuffer.cpp