This class implements a plugin library manager.

It keeps track of a list of plugin handlers. A plugin handler knows which plugin library to load to get a specific class that is used to extend the functionality of a specific base class and how to create an object of this class. For example, to extend the base class TFile to be able to read SQLite files one needs to load the plugin library libRSQLite.so which defines the TRSQLiteServer class. This loading should be triggered when a given URI contains a regular expression defined by the handler.

Plugin handlers can be defined via macros in a list of plugin directories. With $ROOTSYS/etc/plugins the default top plugin directory specified in $ROOTSYS/etc/system.rootrc. Additional directories can be specified by adding them to the end of the list. Macros for identical plugin handlers in later directories will override previous ones (the inverse of normal search path behavior). The macros must have names like <BaseClass>/PX0_<PluginClass>.C, e.g. TSQLServer/P20_TMySQLServer.C, to allow easy sorting and grouping. If the BaseClass is in a namespace the directory must have the name NameSpace@BaseClass as : is a reserved pathname character on some operating systems. Macros not beginning with 'P' and ending with ".C" are ignored. These macros typically look like:

void P10_TDCacheFile()
{
    gPluginMgr->AddHandler("TFile", "^dcache", "TDCacheFile",
       "DCache", "TDCacheFile(const char*,Option_t*)");
}

Plugin handlers can also be defined via resources in the .rootrc file. Although now deprecated this method still works for backward compatibility, e.g.:

Plugin.TSQLServer:  ^mysql:  TMySQLServer MySQL  "<constructor>"
+Plugin.TSQLServer: ^pgsql:  TPgSQLServer PgSQL  "<constructor>"
Plugin.TVirtualFitter: *     TFitter      Minuit "TFitter(Int_t)"

Where the + in front of Plugin.TSQLServer says that it extends the existing definition of TSQLServer, useful when there is more than one plugin that can extend the same base class. The "<constructor>" should be the constructor or a static method that generates an instance of the specified class. Global methods should start with "::" in their name, like "::CreateFitter()". Instead of being a shared library a plugin can also be a CINT script, so instead of libDialog.so one can have Dialog.C. The * is a placeholder in case there is no need for a URI to differentiate between different plugins for the same base class. For the default plugins see $ROOTSYS/etc/system.rootrc.

Plugin handlers can also be registered at run time, e.g.:

gPluginMgr->AddHandler("TSQLServer", "^sqlite:",
                       "TSQLiteServer", "RSQLite",
          "TSQLiteServer(const char*,const char*,const char*)");

A list of currently defined handlers can be printed using:

gPluginMgr->Print(); // use option="a" to see ctors

TPluginManager::Print

void Print(Option_t *opt="") const

Print list of registered plugin handlers.

Definition TPluginManager.cxx:610

The use of the plugin library manager removes all textual references to hard-coded class and library names and the resulting dependencies in the base classes. The plugin manager is used to extend a.o. TFile, TSQLServer, TGrid, etc. functionality.

Definition at line 181 of file TPluginManager.h.

Public Member Functions
	TPluginManager ()

	~TPluginManager ()
	Clean up the plugin manager.

void	AddHandler (const char base, const char regexp, const char className, const char pluginName, const char ctor=0, const char origin=0)
	Add plugin handler to the list of handlers.

TPluginHandler *	FindHandler (const char base, const char uri=0)
	Returns the handler if there exists a handler for the specified URI.

void	LoadHandlersFromEnv (TEnv *env)
	Load plugin handlers specified in config file, like:

void	LoadHandlersFromPluginDirs (const char *base=0)
	Load plugin handlers specified via macros in a list of plugin directories.

void	Print (Option_t *opt="") const
	Print list of registered plugin handlers.

void	RemoveHandler (const char base, const char regexp=0)
	Remove handler for the specified base class and the specified regexp.

Int_t	WritePluginMacros (const char dir, const char plugin=0) const
	Write in the specified directory the plugin macros.

Int_t	WritePluginRecords (const char envFile, const char plugin=0) const
	Write in the specified environment config file the plugin records.

Public Member Functions inherited from TObject
	TObject ()
	TObject constructor.

	TObject (const TObject &object)
	TObject copy ctor.

virtual	~TObject ()
	TObject destructor.

void	AbstractMethod (const char *method) const
	Use this method to implement an "abstract" method that you don't want to leave purely abstract.

virtual void	AppendPad (Option_t *option="")
	Append graphics object to current pad.

virtual void	Browse (TBrowser *b)
	Browse object. May be overridden for another default action.

ULong_t	CheckedHash ()
	Check and record whether this class has a consistent Hash/RecursiveRemove setup (*) and then return the regular Hash value for this object.

virtual const char *	ClassName () const
	Returns name of class to which the object belongs.

virtual void	Clear (Option_t *="")

virtual TObject *	Clone (const char *newname="") const
	Make a clone of an object using the Streamer facility.

virtual Int_t	Compare (const TObject *obj) const
	Compare abstract method.

virtual void	Copy (TObject &object) const
	Copy this to obj.

virtual void	Delete (Option_t *option="")
	Delete this object.

virtual Int_t	DistancetoPrimitive (Int_t px, Int_t py)
	Computes distance from point (px,py) to the object.

virtual void	Draw (Option_t *option="")
	Default Draw method for all objects.

virtual void	DrawClass () const
	Draw class inheritance tree of the class to which this object belongs.

virtual TObject *	DrawClone (Option_t *option="") const
	Draw a clone of this object in the current selected pad for instance with: `gROOT->SetSelectedPad(gPad)`.

virtual void	Dump () const
	Dump contents of object on stdout.

virtual void	Error (const char method, const char msgfmt,...) const
	Issue error message.

virtual void	Execute (const char method, const char params, Int_t *error=0)
	Execute method on this object with the given parameter string, e.g.

virtual void	Execute (TMethod method, TObjArray params, Int_t *error=0)
	Execute method on this object with parameters stored in the TObjArray.

virtual void	ExecuteEvent (Int_t event, Int_t px, Int_t py)
	Execute action corresponding to an event at (px,py).

virtual void	Fatal (const char method, const char msgfmt,...) const
	Issue fatal error message.

virtual TObject *	FindObject (const char *name) const
	Must be redefined in derived classes.

virtual TObject *	FindObject (const TObject *obj) const
	Must be redefined in derived classes.

virtual Option_t *	GetDrawOption () const
	Get option used by the graphics system to draw this object.

virtual const char *	GetIconName () const
	Returns mime type name of object.

virtual const char *	GetName () const
	Returns name of object.

virtual char *	GetObjectInfo (Int_t px, Int_t py) const
	Returns string containing info about the object at position (px,py).

virtual Option_t *	GetOption () const

virtual const char *	GetTitle () const
	Returns title of object.

virtual UInt_t	GetUniqueID () const
	Return the unique object id.

virtual Bool_t	HandleTimer (TTimer *timer)
	Execute action in response of a timer timing out.

virtual ULong_t	Hash () const
	Return hash value for this object.

Bool_t	HasInconsistentHash () const
	Return true is the type of this object is known to have an inconsistent setup for Hash and RecursiveRemove (i.e.

virtual void	Info (const char method, const char msgfmt,...) const
	Issue info message.

virtual Bool_t	InheritsFrom (const char *classname) const
	Returns kTRUE if object inherits from class "classname".

virtual Bool_t	InheritsFrom (const TClass *cl) const
	Returns kTRUE if object inherits from TClass cl.

virtual void	Inspect () const
	Dump contents of this object in a graphics canvas.

void	InvertBit (UInt_t f)

virtual Bool_t	IsEqual (const TObject *obj) const
	Default equal comparison (objects are equal if they have the same address in memory).

virtual Bool_t	IsFolder () const
	Returns kTRUE in case object contains browsable objects (like containers or lists of other objects).

R__ALWAYS_INLINE Bool_t	IsOnHeap () const

virtual Bool_t	IsSortable () const

R__ALWAYS_INLINE Bool_t	IsZombie () const

virtual void	ls (Option_t *option="") const
	The ls function lists the contents of a class on stdout.

void	MayNotUse (const char *method) const
	Use this method to signal that a method (defined in a base class) may not be called in a derived class (in principle against good design since a child class should not provide less functionality than its parent, however, sometimes it is necessary).

virtual Bool_t	Notify ()
	This method must be overridden to handle object notification.

void	Obsolete (const char method, const char asOfVers, const char *removedFromVers) const
	Use this method to declare a method obsolete.

void	operator delete (void *ptr)
	Operator delete.

void	operator delete[] (void *ptr)
	Operator delete [].

void *	operator new (size_t sz)

void *	operator new (size_t sz, void *vp)

void *	operator new[] (size_t sz)

void *	operator new[] (size_t sz, void *vp)

TObject &	operator= (const TObject &rhs)
	TObject assignment operator.

virtual void	Paint (Option_t *option="")
	This method must be overridden if a class wants to paint itself.

virtual void	Pop ()
	Pop on object drawn in a pad to the top of the display list.

virtual Int_t	Read (const char *name)
	Read contents of object with specified name from the current directory.

virtual void	RecursiveRemove (TObject *obj)
	Recursively remove this object from a list.

void	ResetBit (UInt_t f)

virtual void	SaveAs (const char filename="", Option_t option="") const
	Save this object in the file specified by filename.

virtual void	SavePrimitive (std::ostream &out, Option_t *option="")
	Save a primitive as a C++ statement(s) on output stream "out".

void	SetBit (UInt_t f)

void	SetBit (UInt_t f, Bool_t set)
	Set or unset the user status bits as specified in f.

virtual void	SetDrawOption (Option_t *option="")
	Set drawing option for object.

virtual void	SetUniqueID (UInt_t uid)
	Set the unique object id.

virtual void	SysError (const char method, const char msgfmt,...) const
	Issue system error message.

R__ALWAYS_INLINE Bool_t	TestBit (UInt_t f) const

Int_t	TestBits (UInt_t f) const

virtual void	UseCurrentStyle ()
	Set current style settings in this object This function is called when either TCanvas::UseCurrentStyle or TROOT::ForceStyle have been invoked.

virtual void	Warning (const char method, const char msgfmt,...) const
	Issue warning message.

virtual Int_t	Write (const char *name=0, Int_t option=0, Int_t bufsize=0)
	Write this object to the current directory.

virtual Int_t	Write (const char *name=0, Int_t option=0, Int_t bufsize=0) const
	Write this object to the current directory.

Private Member Functions
	TPluginManager (const TPluginManager &)=delete
	true if we are running LoadHandlersFromPluginDirs

void	LoadHandlerMacros (const char *path)
	Load all plugin macros from the specified path/base directory.

TPluginManager &	operator= (const TPluginManager &)=delete

Private Attributes
THashTable *	fBasesLoaded

TList *	fHandlers

Bool_t	fReadingDirs
	table of base classes already checked or loaded

Additional Inherited Members
Public Types inherited from TObject
enum	{ kIsOnHeap = 0x01000000 , kNotDeleted = 0x02000000 , kZombie = 0x04000000 , kInconsistent = 0x08000000 , kBitMask = 0x00ffffff }

enum	{ kSingleKey = BIT(0) , kOverwrite = BIT(1) , kWriteDelete = BIT(2) }

enum	EDeprecatedStatusBits { kObjInCanvas = BIT(3) }

enum	EStatusBits { kCanDelete = BIT(0) , kMustCleanup = BIT(3) , kIsReferenced = BIT(4) , kHasUUID = BIT(5) , kCannotPick = BIT(6) , kNoContextMenu = BIT(8) , kInvalidObject = BIT(13) }

Static Public Member Functions inherited from TObject
static Long_t	GetDtorOnly ()
	Return destructor only flag.

static Bool_t	GetObjectStat ()
	Get status of object stat flag.

static void	SetDtorOnly (void *obj)
	Set destructor only flag.

static void	SetObjectStat (Bool_t stat)
	Turn on/off tracking of objects in the TObjectTable.

Protected Types inherited from TObject
enum	{ kOnlyPrepStep = BIT(3) }

Protected Member Functions inherited from TObject
virtual void	DoError (int level, const char location, const char fmt, va_list va) const
	Interface to ErrorHandler (protected).

void	MakeZombie ()

#include <TPluginManager.h>

Inheritance diagram for TPluginManager:

[legend]

Constructor & Destructor Documentation

◆ TPluginManager() [1/2]

TPluginManager::TPluginManager ( const TPluginManager & )

privatedelete

true if we are running LoadHandlersFromPluginDirs

◆ TPluginManager() [2/2]

TPluginManager::TPluginManager ( )

inline

Definition at line 193 of file TPluginManager.h.

◆ ~TPluginManager()

TPluginManager::~TPluginManager ( )

Clean up the plugin manager.

Definition at line 336 of file TPluginManager.cxx.

Member Function Documentation

◆ AddHandler()

void TPluginManager::AddHandler	(	const char *	base,
		const char *	regexp,
		const char *	className,
		const char *	pluginName,
		const char *	ctor = `0`,
		const char *	origin = `0`
	)

Add plugin handler to the list of handlers.

If there is already a handler defined for the same base and regexp it will be replaced.

Definition at line 528 of file TPluginManager.cxx.

◆ FindHandler()

TPluginHandler * TPluginManager::FindHandler	(	const char *	base,
		const char *	uri = `0`
	)

Returns the handler if there exists a handler for the specified URI.

The uri can be 0 in which case the first matching plugin handler will be returned. Returns 0 in case handler is not found.

Definition at line 580 of file TPluginManager.cxx.

◆ LoadHandlerMacros()

void TPluginManager::LoadHandlerMacros ( const char * path )

private

Load all plugin macros from the specified path/base directory.

Definition at line 390 of file TPluginManager.cxx.

◆ LoadHandlersFromEnv()

void TPluginManager::LoadHandlersFromEnv ( TEnv * env )

Load plugin handlers specified in config file, like:

Plugin.TSQLServer: ^mysql: TMySQLServer MySQL "TMySQLServer(...)"

+Plugin.TSQLServer: ^pgsql: TPgSQLServer PgSQL "TPgSQLServer(...)"

The + allows the extension of an already defined resource (see TEnv).

Definition at line 350 of file TPluginManager.cxx.

◆ LoadHandlersFromPluginDirs()

void TPluginManager::LoadHandlersFromPluginDirs ( const char * base = 0 )

Load plugin handlers specified via macros in a list of plugin directories.

The $ROOTSYS/etc/plugins is the default top plugin directory specified in $ROOTSYS/etc/system.rootrc. The macros must have names like <BaseClass>/PX0_<PluginClass>.C, e.g. //TSQLServer/P20_TMySQLServer.C, to allow easy sorting and grouping. If the BaseClass is in a namespace the directory must have the name NameSpace@BaseClass as : is a reserved pathname character on some operating systems. Macros not beginning with 'P' and ending with ".C" are ignored. If base is specified only plugin macros for that base class are loaded. The macros typically should look like:

void P10_TDCacheFile()
{
    gPluginMgr->AddHandler("TFile", "^dcache", "TDCacheFile",
       "DCache", "TDCacheFile(const char*,Option_t*,const char*,Int_t)");
}

In general these macros should not cause side effects, by changing global ROOT state via, e.g. gSystem calls, etc. However, in specific cases this might be useful, e.g. adding a library search path, adding a specific dependency, check on some OS or ROOT capability or downloading of the plugin.

Definition at line 449 of file TPluginManager.cxx.

◆ operator=()

TPluginManager & TPluginManager::operator= ( const TPluginManager & )

privatedelete

◆ Print()

void TPluginManager::Print ( Option_t * opt = "" ) const

virtual

Print list of registered plugin handlers.

If option is "a" print also the ctor's that will be used.

Reimplemented from TObject.

Definition at line 610 of file TPluginManager.cxx.

◆ RemoveHandler()

void TPluginManager::RemoveHandler	(	const char *	base,
		const char *	regexp = `0`
	)

Remove handler for the specified base class and the specified regexp.

If regexp=0 remove all handlers for the specified base.

Definition at line 557 of file TPluginManager.cxx.

◆ WritePluginMacros()

Int_t TPluginManager::WritePluginMacros	(	const char *	dir,
		const char *	plugin = `0`
	)		const

Write in the specified directory the plugin macros.

If plugin is specified and if it is a base class all macros for that base will be written. If it is a plugin class name, only that one macro will be written. If plugin is 0 all macros are written. Returns -1 if dir does not exist, 0 otherwise.

Definition at line 640 of file TPluginManager.cxx.

◆ WritePluginRecords()

Int_t TPluginManager::WritePluginRecords	(	const char *	envFile,
		const char *	plugin = `0`
	)		const

Write in the specified environment config file the plugin records.

If plugin is specified and if it is a base class all records for that base will be written. If it is a plugin class name, only that one record will be written. If plugin is 0 all macros are written. If envFile is 0 or "" the records are written to stdout. Returns -1 if envFile cannot be created or opened, 0 otherwise.

Definition at line 724 of file TPluginManager.cxx.

Member Data Documentation

◆ fBasesLoaded

THashTable* TPluginManager::fBasesLoaded

private

Definition at line 185 of file TPluginManager.h.

◆ fHandlers

TList* TPluginManager::fHandlers

private

Definition at line 184 of file TPluginManager.h.

◆ fReadingDirs

Bool_t TPluginManager::fReadingDirs

private

table of base classes already checked or loaded

Definition at line 186 of file TPluginManager.h.

core/base/inc/TPluginManager.h

core/base/src/TPluginManager.cxx

Public Member Functions

Private Member Functions

Private Attributes

Additional Inherited Members

Constructor & Destructor Documentation

◆ TPluginManager() [1/2]

◆ TPluginManager() [2/2]

◆ ~TPluginManager()

Member Function Documentation

◆ AddHandler()

◆ FindHandler()

◆ LoadHandlerMacros()

◆ LoadHandlersFromEnv()

◆ LoadHandlersFromPluginDirs()

◆ operator=()

◆ Print()

◆ RemoveHandler()

◆ WritePluginMacros()

◆ WritePluginRecords()

Member Data Documentation

◆ fBasesLoaded

◆ fHandlers

◆ fReadingDirs