vrs::FileHandlerFactory Class Reference

A factory system for FileHandlers, allowing the runtime registration & usage of custom FileHandler implementations. More...

#include <FileHandlerFactory.h>

Public Member Functions
void	registerFileDelegator (const string &name, unique_ptr< FileDelegator > &&delegator)
	Delegators operating on FileSpec.fileHandlerName.
void	unregisterFileDelegator (const string &name)
void	registerExtraDelegator (const string &extraName, const string &extraValue, unique_ptr< FileDelegator > &&delegator)
void	unregisterExtraDelegator (const string &extraName, const string &extraValue)
FileDelegator *	getExtraDelegator (const FileSpec &fileSpec)
FileDelegator *	getExtraDelegator (const string &extraName, const string &extraValue)
void	registerFileHandler (unique_ptr< FileHandler > &&fileHandler)
	Delegators operating on FileSpec.fileHandlerName.
void	unregisterFileHandler (const string &fileHandlerName)
unique_ptr< FileHandler >	getFileHandler (const string &name)
FileDelegator *	getFileDelegator (const string &name)
virtual int	delegateOpen (const string &path, unique_ptr< FileHandler > &outNewDelegate)
virtual int	delegateOpen (const FileSpec &fileSpec, unique_ptr< FileHandler > &outNewDelegate)
virtual int	parseUri (FileSpec &inOutFileSpec, size_t colonIndex)

Static Public Member Functions
static FileHandlerFactory &	getInstance ()

Detailed Description

A factory system for FileHandlers, allowing the runtime registration & usage of custom FileHandler implementations.

Member Function Documentation

delegateOpen()

int vrs::FileHandlerFactory::delegateOpen ( const string &  path, unique_ptr< FileHandler > &  outNewDelegate  )

virtual

Use different strategies to determine which FileHandler should be used to open the file path.

Parameters

path	a path or other form of identification for a file.
outNewDelegate	If provided, might be a fallback FileHandler to use. On success, will be set to the right FileHandler to handle the provided path. On failure, maybe unset.

Returns

A status code, 0 meaning success.

path identification methods: 1) File paths; examples /posix/path/to/file, or C:\\Path\\To\\File 2) URI paths, probably mapped to custom FileHandler implementations registered externally. 3) JSON "paths" containing: storage - name of a registered file handler to use chunks - storage specific references (path, url, ...) to successive chunks of data

{
    "storage": "required-name-of-file-handler",
    "chunks": [ "chunk_path_1", "chunk2_path_2", ... ],
  }

JSON paths are converted into FileSpec objects by FileSpec::fromJson() 4) If all the above methods fail, fall back to opening path as file path.

Method is virtual to enable mock FileHandlerFactories to be created for unit testing.

parseUri()

int vrs::FileHandlerFactory::parseUri ( FileSpec &  inOutFileSpec, size_t  colonIndex  )

virtual

Parsing URIs can be customized by FileHandler and FileDelegators. Note that extra delegators only get the parseUri() callback after parsing is complete, but they can still completely change the FileSpec.

registerExtraDelegator()

void vrs::FileHandlerFactory::registerExtraDelegator	(	const string &	extraName,
		const string &	extraValue,
		unique_ptr< FileDelegator > &&	delegator
	)

Delegators operating on particular key-value pairs of FileSpec.extras so this type of URI can be customized: a_scheme:/my/path?my_unique_name=my_unique_value

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

• vrs/FileHandlerFactory.h
• vrs/FileHandlerFactory.cpp