Send application output to a "pager" application such as "more" or "less". More...

#include <tsOutputPager.h>

Inheritance diagram for ts::OutputPager:

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Collaboration diagram for ts::OutputPager:

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Public Types
enum	InputMode { STDIN_PARENT , STDIN_PIPE , STDIN_NONE }
	How to standard input in the created process. More...

enum	OutputMode { KEEP_BOTH , STDOUT_ONLY , STDERR_ONLY , STDOUT_PIPE , STDOUTERR_PIPE }
	How to merge standard output and standard error in the created process. More...

using	SuperClass = std::basic_ostream< char >
	Explicit reference to the public superclass.

enum	WaitMode { ASYNCHRONOUS , SYNCHRONOUS , EXIT_PROCESS }
	How to wait for the created process when close() is invoked. More...

Public Member Functions
	OutputPager (const UString &envName=DEFAULT_PAGER, bool stdoutOnly=false)
	Default constructor.

virtual	~OutputPager () override
	Destructor.

void	abortPipeReadWrite ()
	Abort any currenly input/output operation in the pipe.

bool	canPage () const
	Check if we can run a pager.

bool	close (Report &report)
	Close the pipe.

virtual bool	endOfStream () override
	Check if the end of stream was reached.

bool	getIgnoreAbort () const
	Get "ignore abort".

bool	isBroken () const
	Check if the pipe was broken.

bool	isOpen () const
	Check if the process is running and the pipe is open (when used).

bool	isSynchronous () const
	Check if synchronous mode is active (ie.

bool	open (bool synchronous, size_t buffer_size, Report &report)
	Create the process, open the pipe.

bool	open (const UString &command, WaitMode wait_mode, size_t buffer_size, Report &report, OutputMode out_mode, InputMode in_mode)
	Create the process, open the optional pipe.

UString	pagerCommand () const
	Get the pager command which is used.

virtual bool	readStreamChunks (void *addr, size_t max_size, size_t chunk_size, size_t &ret_size, Report &report)
	Read chunks of data from the stream.

virtual bool	readStreamComplete (void *addr, size_t max_size, size_t &ret_size, Report &report)
	Read complete data from the stream.

virtual bool	readStreamPartial (void *addr, size_t max_size, size_t &ret_size, Report &report) override
	Read partial data from the stream.

void	setIgnoreAbort (bool on)
	Set "ignore abort".

bool	write (const UString &text, Report &report)
	Write data to the pipe (received at process' standard input).

virtual bool	writeStream (const void *addr, size_t size, size_t &written_size, Report &report) override
	Write data to the stream.

Static Public Member Functions
static bool	GetOutput (UString &output, const UString &command, Report &report, bool include_stderr=false)
	This static method launches a command and gets its output as text.

static bool	Launch (const UString &command, Report &report, OutputMode out_mode=KEEP_BOTH, InputMode in_mode=STDIN_PARENT, WaitMode wait_mode=ASYNCHRONOUS)
	This static method launches a command, without pipe, optionally without waiting for the completion of the command process.

Static Public Attributes
static constexpr const UChar *const	DEFAULT_PAGER = u"PAGER"
	Default name of the environment variable containing the pager command.

static constexpr size_t	DEFAULT_STREAM_BUFFER_SIZE = 1024
	Default stream buffer size in bytes.

Protected Member Functions
virtual bool	writeStreamBuffer (const void *addr, size_t size) override
	Write buffered data to underlying output devicen whatever it is.

Detailed Description

Send application output to a "pager" application such as "more" or "less".

Paging is done on stdout or stderr or both, depending on which is a terminal. If neither stdout nor stderr are terminals, paging is not allowed.

Member Enumeration Documentation

◆ WaitMode

enum ts::ForkPipe::WaitMode

inherited

How to wait for the created process when close() is invoked.

No pipe can be used with EXIT_PROCESS because there would be nobody on the other end of the pipe.

Enumerator
ASYNCHRONOUS	Don't wait, close() will return immediately.
SYNCHRONOUS	Wait for process completion during close().
EXIT_PROCESS	Exit parent process during open(). UNIX: call exec(), Windows: call exit() after process creation.

◆ InputMode

enum ts::ForkPipe::InputMode

inherited

How to standard input in the created process.

The pipe can be used either on input or output, but not both. So, STDIN_PIPE is also forbidden with output mode is either STDOUT_PIPE or STDOUTERR_PIPE.

Enumerator
STDIN_PARENT	Keep same stdin as current (parent) process.
STDIN_PIPE	Use the pipe as stdin.
STDIN_NONE	No standard input (the null device in fact).

◆ OutputMode

enum ts::ForkPipe::OutputMode

inherited

How to merge standard output and standard error in the created process.

Enumerator
KEEP_BOTH	Keep same stdout and stderr as current (parent) process.
STDOUT_ONLY	Merge stderr into current stdout.
STDERR_ONLY	Merge stdout into current stderr.
STDOUT_PIPE	Use the pipe to receive stdout, keep same stderr as current (parent) process.
STDOUTERR_PIPE	Use the pipe to receive a merge of stdout and stderr.

Constructor & Destructor Documentation

◆ OutputPager()

ts::OutputPager::OutputPager	(	const UString &	envName = `DEFAULT_PAGER`,
		bool	stdoutOnly = `false`
	)

explicit

Default constructor.

Parameters

[in]	envName	Name of the optional environment variable containing the pager command name.
[in]	stdoutOnly	If true, use only stdout. If false, if stdout is not a terminal but stderr is one, then use stderr for paging.

Member Function Documentation

◆ canPage()

bool ts::OutputPager::canPage ( ) const

inline

Check if we can run a pager.

To run a pager, we must have found a valid pager command and either stdout or stderr must be a terminal.

Returns: True if we can page.

◆ pagerCommand()

UString ts::OutputPager::pagerCommand ( ) const

inline

Get the pager command which is used.

Returns: The pager command which is used.

◆ open() [1/2]

bool ts::OutputPager::open	(	bool	synchronous,
		size_t	buffer_size,
		Report &	report
	)

Create the process, open the pipe.

Parameters

[in]	synchronous	If true, wait for process termination in close().
[in]	buffer_size	The pipe buffer size in bytes. Used on Windows only. Zero means default.
[in,out]	report	Where to report errors.

Returns: True on success, false on error.

◆ write()

bool ts::OutputPager::write	(	const UString &	text,
		Report &	report
	)

Write data to the pipe (received at process' standard input).

Parameters

[in]	text	Text to write.
[in,out]	report	Where to report errors.

Returns: True on success, false on error.

◆ open() [2/2]

bool ts::ForkPipe::open	(	const UString &	command,
		WaitMode	wait_mode,
		size_t	buffer_size,
		Report &	report,
		OutputMode	out_mode,
		InputMode	in_mode
	)

inherited

Create the process, open the optional pipe.

Parameters

[in]	command	The command to execute.
[in]	wait_mode	How to wait for process termination in close().
[in]	buffer_size	The pipe buffer size in bytes. Used on Windows only. Zero means default.
[in,out]	report	Where to report errors.
[in]	out_mode	How to handle stdout and stderr.
[in]	in_mode	How to handle stdin. Use the pipe by default. When set to KEEP_STDIN, no pipe is created.

Returns: True on success, false on error. Do not return on success when wait_mode is EXIT_PROCESS.

◆ close()

bool ts::ForkPipe::close ( Report & report )

inherited

Close the pipe.

Optionally wait for process termination if wait_mode was SYNCHRONOUS on open().

Parameters

[in,out] report Where to report errors.

Returns: True on success, false on error.

◆ isOpen()

bool ts::ForkPipe::isOpen ( ) const

inlineinherited

Check if the process is running and the pipe is open (when used).

Returns: True if the process is running and the pipe is open.

◆ isBroken()

bool ts::ForkPipe::isBroken ( ) const

inlineinherited

Check if the pipe was broken.

Returns: True if was broken (unexpected process termination for instance).

◆ isSynchronous()

bool ts::ForkPipe::isSynchronous ( ) const

inlineinherited

Check if synchronous mode is active (ie.

will wait for process termination).

Returns: True if synchronous mode is active.

◆ setIgnoreAbort()

void ts::ForkPipe::setIgnoreAbort ( bool on )

inlineinherited

Set "ignore abort".

Parameters

[in] on If true and the process aborts, do not report error when writing data. when writing data.

◆ getIgnoreAbort()

bool ts::ForkPipe::getIgnoreAbort ( ) const

inlineinherited

Get "ignore abort".

Returns: True if, when the process aborts, do not report error when writing data.

◆ abortPipeReadWrite()

void ts::ForkPipe::abortPipeReadWrite ( )

inherited

Abort any currenly input/output operation in the pipe.

The pipe is left in a broken state and can be only closed.

◆ Launch()

static bool ts::ForkPipe::Launch	(	const UString &	command,
		Report &	report,
		OutputMode	out_mode = `KEEP_BOTH`,
		InputMode	in_mode = `STDIN_PARENT`,
		WaitMode	wait_mode = `ASYNCHRONOUS`
	)

staticinherited

This static method launches a command, without pipe, optionally without waiting for the completion of the command process.

Parameters

[in]	command	The command to execute.
[in,out]	report	Where to report errors.
[in]	out_mode	How to handle stdout and stderr. Must be KEEP_BOTH (default), STDOUT_ONLY or STDERR_ONLY. Output modes using pipes are forbidden.
[in]	in_mode	How to handle stdin. Must be STDIN_PARENT (default) or STDIN_NONE. Input modes using pipes are forbidden.
[in]	wait_mode	How to wait for the command process. Must be ASYNCHRONOUS (default) or SYNCHRONOUS.

Returns: True on success, false on error.

◆ GetOutput()

static bool ts::ForkPipe::GetOutput	(	UString &	output,
		const UString &	command,
		Report &	report,
		bool	include_stderr = `false`
	)

staticinherited

This static method launches a command and gets its output as text.

Parameters

[in]	output	The output of the command.
[in]	command	The command to execute.
[in,out]	report	Where to report errors.
[in]	include_stderr	If false, the standard error of the command is the same as the parent process. If true, the standard error is merged with the standard output in output.

Returns: True on success, false on error.

◆ endOfStream()

virtual bool ts::ForkPipe::endOfStream ( )

overridevirtualinherited

Check if the end of stream was reached.

Returns: True on end of stream, false otherwise.

Implements ts::AbstractReadStreamInterface.

◆ readStreamPartial()

virtual bool ts::ForkPipe::readStreamPartial	(	void *	addr,
		size_t	max_size,
		size_t &	ret_size,
		Report &	report
	)

overridevirtualinherited

Read partial data from the stream.

Wait and read at least one byte. Don't try to read exactly max_size bytes. If ret_size is less than max_bytes, it is possible to read more.

Parameters

[out]	addr	Address of the buffer for the incoming data.
[in]	max_size	Maximum size in bytes of the buffer.
[out]	ret_size	Returned input size in bytes. If zero, end of file has been reached or an error occurred.
[in,out]	report	Where to report errors.

Returns: True on success, false on error.

Implements ts::AbstractReadStreamInterface.

◆ writeStream()

virtual bool ts::ForkPipe::writeStream	(	const void *	addr,
		size_t	size,
		size_t &	written_size,
		Report &	report
	)

overridevirtualinherited

Write data to the stream.

All bytes are written to the stream, blocking or retrying when necessary.

Parameters

[in]	addr	Address of the data to write.
[in]	size	Size in bytes of the data to write.
[out]	written_size	Actually written size in bytes. Can be less than size in case of error in the middle of the write.
[in,out]	report	Where to report errors.

Returns: True on success, false on error.

Implements ts::AbstractWriteStreamInterface.

◆ writeStreamBuffer()

virtual bool ts::ForkPipe::writeStreamBuffer	(	const void *	addr,
		size_t	size
	)

overrideprotectedvirtualinherited

Write buffered data to underlying output devicen whatever it is.

Must be implemented by subclasses.

Parameters

[in]	addr	Buffered data address.
[in]	size	Buffered data size in bytes.

Returns: True on success, false on error.

Implements ts::AbstractOutputStream.

◆ readStreamComplete()

virtual bool ts::AbstractReadStreamInterface::readStreamComplete	(	void *	addr,
		size_t	max_size,
		size_t &	ret_size,
		Report &	report
	)

virtualinherited

Read complete data from the stream.

Wait and read exactly max_size bytes. If ret_size is less than max_bytes, it is not possible to read more. End of file has probably been reached.

Parameters

[out]	addr	Address of the buffer for the incoming data.
[in]	max_size	Maximum size in bytes of the buffer.
[out]	ret_size	Returned input size in bytes.
[in,out]	report	Where to report errors.

Returns: True on success, false on error.

◆ readStreamChunks()

virtual bool ts::AbstractReadStreamInterface::readStreamChunks	(	void *	addr,
		size_t	max_size,
		size_t	chunk_size,
		size_t &	ret_size,
		Report &	report
	)

virtualinherited

Read chunks of data from the stream.

Parameters

[out]	addr	Address of the buffer for the incoming data.
[in]	max_size	Maximum size in bytes of the buffer.
[in]	chunk_size	If not zero, make sure that the input size is always a multiple of chunk_size. If the initial read ends in the middle of a chunk, read again and again, up to the end of the current chunk or end of file.
[out]	ret_size	Returned input size in bytes.
[in,out]	report	Where to report errors.

Returns: True on success, false on error.

Member Data Documentation

◆ DEFAULT_PAGER

constexpr const UChar* const ts::OutputPager::DEFAULT_PAGER = u"PAGER"

staticconstexpr

Default name of the environment variable containing the pager command.

The default environment variable is PAGER.

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

tsOutputPager.h

Public Types

Public Member Functions

Static Public Member Functions

Static Public Attributes

Protected Member Functions

Detailed Description

Member Enumeration Documentation

◆ WaitMode

◆ InputMode

◆ OutputMode

Constructor & Destructor Documentation

◆ OutputPager()

Member Function Documentation

◆ canPage()

◆ pagerCommand()

◆ open() [1/2]

◆ write()

◆ open() [2/2]

◆ close()

◆ isOpen()

◆ isBroken()

◆ isSynchronous()

◆ setIgnoreAbort()

◆ getIgnoreAbort()

◆ abortPipeReadWrite()

◆ Launch()

◆ GetOutput()

◆ endOfStream()

◆ readStreamPartial()

◆ writeStream()

◆ writeStreamBuffer()

◆ readStreamComplete()

◆ readStreamChunks()

Member Data Documentation

◆ DEFAULT_PAGER