tesseract_common::PluginLoader Class Reference

This is a utility class for loading plugins within Tesseract. More...

#include <plugin_loader.h>

Inheritance diagram for tesseract_common::PluginLoader:

Collaboration diagram for tesseract_common::PluginLoader:

Public Member Functions
template<class PluginBase >
std::shared_ptr< PluginBase >	instantiate (const std::string &plugin_name) const
	Instantiate a plugin with the provided name. More...
bool	isPluginAvailable (const std::string &plugin_name) const
	Check if plugin is available. More...
template<class PluginBase >
std::vector< std::string >	getAvailablePlugins () const
	Get the available plugins for the provided PluginBase type. More...
std::vector< std::string >	getAvailablePlugins (const std::string &section) const
	Get the available plugins under the provided section. More...
std::vector< std::string >	getAvailableSections (bool include_hidden=false) const
	Get the available sections within the provided search libraries. More...
int	count () const
	The number of plugins stored. The size of plugins variable. More...

Static Public Member Functions
static void	addSymbolLibraryToSearchLibrariesEnv (const void *symbol_ptr, const std::string &search_libraries_env)
	Utility function to add library containing symbol to the search env variable. More...

Public Attributes
bool	search_system_folders { true }
	Indicate is system folders may be search if plugin is not found in any of the paths. More...
std::set< std::string >	search_paths
	A list of paths to search for plugins. More...
std::set< std::string >	search_libraries
	A list of library names without the prefix or suffix that contain plugins. More...
std::string	search_paths_env
	The environment variable containing plugin search paths. More...
std::string	search_libraries_env
	The environment variable containing plugins. More...

Detailed Description

This is a utility class for loading plugins within Tesseract.

The library_name should not include the prefix 'lib' or suffix '.so'. It will add the correct prefix and suffix based on the OS.

It supports providing additional search paths and set environment variable which should be used when searching for plugins.

The plugin must be exported using the macro TESSERACT_ADD_PLUGIN. In the example below, the first parameter is the derived object and the second is the assigned symbol name which is used for loading Example: TESSERACT_ADD_PLUGIN(my_namespace::MyPlugin, plugin)

PluginLoader loader; loader.search_libraries.insert("my_plugin"); // libmy_plugin.so std::shared_ptr<PluginBase> p = loader.instantiate<PluginBase>("plugin");

Member Function Documentation

addSymbolLibraryToSearchLibrariesEnv()

void tesseract_common::PluginLoader::addSymbolLibraryToSearchLibrariesEnv ( const void *  symbol_ptr, const std::string &  search_libraries_env  )

inlinestatic

Utility function to add library containing symbol to the search env variable.

In some cases the name and location of a library is unknown at runtime, but a symbol can be linked at compile time. This is true for Python auditwheel distributions. This utility function will determine the location of the library, and add it to the library search environment variable so it can be found.

Parameters

symbol_ptr	Pointer to the symbol to find
search_libraries_env	The environmental variable to modify

count()

int tesseract_common::PluginLoader::count ( ) const

inline

The number of plugins stored. The size of plugins variable.

Returns

The number of plugins.

getAvailablePlugins() [1/2]

template<class PluginBase >

std::vector< std::string > tesseract_common::PluginLoader::getAvailablePlugins

Get the available plugins for the provided PluginBase type.

This expects the Plugin base to have a static std::string SECTION_NAME which is used for looking up plugins

Returns

A list of available plugins for the provided PluginBase type

getAvailablePlugins() [2/2]

std::vector< std::string > tesseract_common::PluginLoader::getAvailablePlugins ( const std::string &  section ) const

inline

Get the available plugins under the provided section.

Parameters

section

The section name to get all available plugins

Returns

A list of available plugins under the provided section

getAvailableSections()

std::vector< std::string > tesseract_common::PluginLoader::getAvailableSections ( bool  include_hidden = false ) const

inline

Get the available sections within the provided search libraries.

Returns

A list of available sections

instantiate()

template<class PluginBase >

std::shared_ptr< PluginBase > tesseract_common::PluginLoader::instantiate

(

const std::string &

plugin_name

)

const

Instantiate a plugin with the provided name.

Parameters

plugin_name

The plugin name to find

Returns

A instantiate of the plugin, if nullptr it failed to create plugin

isPluginAvailable()

bool tesseract_common::PluginLoader::isPluginAvailable ( const std::string &  plugin_name ) const

inline

Check if plugin is available.

Parameters

plugin_name

The plugin name to find

Returns

True if plugin is found

Member Data Documentation

search_libraries

std::set<std::string> tesseract_common::PluginLoader::search_libraries

A list of library names without the prefix or suffix that contain plugins.

search_libraries_env

std::string tesseract_common::PluginLoader::search_libraries_env

The environment variable containing plugins.

The plugins are store ins the following format. The library name does not contain prefix or suffix Format: library_name:library_name1:library_name2

search_paths

std::set<std::string> tesseract_common::PluginLoader::search_paths

A list of paths to search for plugins.

search_paths_env

std::string tesseract_common::PluginLoader::search_paths_env

The environment variable containing plugin search paths.

search_system_folders

bool tesseract_common::PluginLoader::search_system_folders { true }

Indicate is system folders may be search if plugin is not found in any of the paths.

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

• tesseract_common/include/tesseract_common/plugin_loader.h
• tesseract_common/include/tesseract_common/plugin_loader.hpp