UrlOrStream< STREAM > Class Template Reference

#include <url.h>

Detailed Description

template<typename STREAM>
class maxon::UrlOrStream< STREAM >

This helper class template can be used for function parameters where the function needs to get a stream, but for convenience also passing a Url as argument to the parameter shall be allowed. In other words, a function

Result<void> LoadSomething(UrlOrInputStream&& input);

can be invoked by passing either a Url or an InputStreamRef to the parameter. It even allows to pass Result<Url> or Result<InputStreamRef>, then the error, if any, will be stored within UrlOrStream and returned by the call to GetStream.

In the implementation of a function with a UrlOrStream parameter, GetStream has to be called to obtain the stream, and finally Close to close the stream (but this will only be done if the stream was obtained from a Url):

Result<void> LoadSomething(UrlOrInputStream&& input)
{
  iferr_scope;
  InputStreamRef& s = input.GetStream() iferr_return;
  // load data from s;
  input.Close() iferr_return; // important: write input.Close(), not s.Close()
  return OK;
}

Public Member Functions
	UrlOrStream ()=default
MAXON_IMPLICIT	UrlOrStream (const Url &url, OPENSTREAMFLAGS flags=OPENSTREAMFLAGS::NONE)
MAXON_IMPLICIT	UrlOrStream (const STREAM &stream)
MAXON_IMPLICIT	UrlOrStream (const Result< Url > &url, OPENSTREAMFLAGS flags=OPENSTREAMFLAGS::NONE)
MAXON_IMPLICIT	UrlOrStream (const Result< STREAM > &stream)
Result< STREAM & >	GetStream ()
const Url &	GetUrl () const
Result< void >	Close ()

Private Attributes
Url	_url
ObjectRef	_stream
Result< void >	_error
OPENSTREAMFLAGS	_flags

Constructor & Destructor Documentation

UrlOrStream() [1/5]

UrlOrStream ( )

default

UrlOrStream() [2/5]

MAXON_IMPLICIT UrlOrStream	(	const Url &	url,
		OPENSTREAMFLAGS	flags = OPENSTREAMFLAGS::NONE
	)

UrlOrStream() [3/5]

MAXON_IMPLICIT UrlOrStream

(

const STREAM &

stream

)

UrlOrStream() [4/5]

MAXON_IMPLICIT UrlOrStream	(	const Result< Url > &	url,
		OPENSTREAMFLAGS	flags = OPENSTREAMFLAGS::NONE
	)

UrlOrStream() [5/5]

MAXON_IMPLICIT UrlOrStream

(

const Result< STREAM > &

stream

)

Member Function Documentation

GetStream()

Result<STREAM&> GetStream

(

)

Returns the stream to use. If this UrlOrStream was constructed with a Url and a stream hasn't yet been opened, a new stream is opened.

Returns

The stream to use.

GetUrl()

const Url& GetUrl

(

)

const

Close()

Result<void> Close

(

)

Close the underlying stream if is has been opened by this UrlOrStream. You have to call this function at the end of the code which has obtained the stream by GetStream(). The stream is closed only if this UrlOrStream was constructed by a Url, but not if is was constructed by a stream.

Returns

OK on success.

Member Data Documentation

_url

Url _url

private

_stream

ObjectRef _stream

private

_error

Result<void> _error

private

_flags

OPENSTREAMFLAGS _flags

private