Logo ROOT   6.19/01
Reference Guide
TPluginManager Class Reference

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

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 182 of file TPluginManager.h.

Public Member Functions

 TPluginManager ()
 
 ~TPluginManager ()
 Clean up the plugin manager. More...
 
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. More...
 
TPluginHandlerFindHandler (const char *base, const char *uri=0)
 Returns the handler if there exists a handler for the specified URI. More...
 
void 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). More...

 
void LoadHandlersFromPluginDirs (const char *base=0)
 Load plugin handlers specified via macros in a list of plugin directories. More...
 
void Print (Option_t *opt="") const
 Print list of registered plugin handlers. More...
 
void RemoveHandler (const char *base, const char *regexp=0)
 Remove handler for the specified base class and the specified regexp. More...
 
Int_t WritePluginMacros (const char *dir, const char *plugin=0) const
 Write in the specified directory the plugin macros. More...
 
Int_t WritePluginRecords (const char *envFile, const char *plugin=0) const
 Write in the specified environment config file the plugin records. More...
 
- Public Member Functions inherited from TObject
 TObject ()
 TObject constructor. More...
 
 TObject (const TObject &object)
 TObject copy ctor. More...
 
virtual ~TObject ()
 TObject destructor. More...
 
void AbstractMethod (const char *method) const
 Use this method to implement an "abstract" method that you don't want to leave purely abstract. More...
 
virtual void AppendPad (Option_t *option="")
 Append graphics object to current pad. More...
 
virtual void Browse (TBrowser *b)
 Browse object. May be overridden for another default action. More...
 
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. More...
 
virtual const char * ClassName () const
 Returns name of class to which the object belongs. More...
 
virtual void Clear (Option_t *="")
 
virtual TObjectClone (const char *newname="") const
 Make a clone of an object using the Streamer facility. More...
 
virtual Int_t Compare (const TObject *obj) const
 Compare abstract method. More...
 
virtual void Copy (TObject &object) const
 Copy this to obj. More...
 
virtual void Delete (Option_t *option="")
 Delete this object. More...
 
virtual Int_t DistancetoPrimitive (Int_t px, Int_t py)
 Computes distance from point (px,py) to the object. More...
 
virtual void Draw (Option_t *option="")
 Default Draw method for all objects. More...
 
virtual void DrawClass () const
 Draw class inheritance tree of the class to which this object belongs. More...
 
virtual TObjectDrawClone (Option_t *option="") const
 Draw a clone of this object in the current selected pad for instance with: gROOT->SetSelectedPad(gPad). More...
 
virtual void Dump () const
 Dump contents of object on stdout. More...
 
virtual void Error (const char *method, const char *msgfmt,...) const
 Issue error message. More...
 
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. More...
 
virtual void Execute (TMethod *method, TObjArray *params, Int_t *error=0)
 Execute method on this object with parameters stored in the TObjArray. More...
 
virtual void ExecuteEvent (Int_t event, Int_t px, Int_t py)
 Execute action corresponding to an event at (px,py). More...
 
virtual void Fatal (const char *method, const char *msgfmt,...) const
 Issue fatal error message. More...
 
virtual TObjectFindObject (const char *name) const
 Must be redefined in derived classes. More...
 
virtual TObjectFindObject (const TObject *obj) const
 Must be redefined in derived classes. More...
 
virtual Option_tGetDrawOption () const
 Get option used by the graphics system to draw this object. More...
 
virtual const char * GetIconName () const
 Returns mime type name of object. More...
 
virtual const char * GetName () const
 Returns name of object. More...
 
virtual char * GetObjectInfo (Int_t px, Int_t py) const
 Returns string containing info about the object at position (px,py). More...
 
virtual Option_tGetOption () const
 
virtual const char * GetTitle () const
 Returns title of object. More...
 
virtual UInt_t GetUniqueID () const
 Return the unique object id. More...
 
virtual Bool_t HandleTimer (TTimer *timer)
 Execute action in response of a timer timing out. More...
 
virtual ULong_t Hash () const
 Return hash value for this object. More...
 
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. More...
 
virtual void Info (const char *method, const char *msgfmt,...) const
 Issue info message. More...
 
virtual Bool_t InheritsFrom (const char *classname) const
 Returns kTRUE if object inherits from class "classname". More...
 
virtual Bool_t InheritsFrom (const TClass *cl) const
 Returns kTRUE if object inherits from TClass cl. More...
 
virtual void Inspect () const
 Dump contents of this object in a graphics canvas. More...
 
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). More...
 
virtual Bool_t IsFolder () const
 Returns kTRUE in case object contains browsable objects (like containers or lists of other objects). More...
 
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. More...
 
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). More...
 
virtual Bool_t Notify ()
 This method must be overridden to handle object notification. More...
 
void Obsolete (const char *method, const char *asOfVers, const char *removedFromVers) const
 Use this method to declare a method obsolete. More...
 
void operator delete (void *ptr)
 Operator delete. More...
 
void operator delete[] (void *ptr)
 Operator delete []. More...
 
voidoperator new (size_t sz)
 
voidoperator new (size_t sz, void *vp)
 
voidoperator new[] (size_t sz)
 
voidoperator new[] (size_t sz, void *vp)
 
TObjectoperator= (const TObject &rhs)
 TObject assignment operator. More...
 
virtual void Paint (Option_t *option="")
 This method must be overridden if a class wants to paint itself. More...
 
virtual void Pop ()
 Pop on object drawn in a pad to the top of the display list. More...
 
virtual Int_t Read (const char *name)
 Read contents of object with specified name from the current directory. More...
 
virtual void RecursiveRemove (TObject *obj)
 Recursively remove this object from a list. More...
 
void ResetBit (UInt_t f)
 
virtual void SaveAs (const char *filename="", Option_t *option="") const
 Save this object in the file specified by filename. More...
 
virtual void SavePrimitive (std::ostream &out, Option_t *option="")
 Save a primitive as a C++ statement(s) on output stream "out". More...
 
void SetBit (UInt_t f, Bool_t set)
 Set or unset the user status bits as specified in f. More...
 
void SetBit (UInt_t f)
 
virtual void SetDrawOption (Option_t *option="")
 Set drawing option for object. More...
 
virtual void SetUniqueID (UInt_t uid)
 Set the unique object id. More...
 
virtual void SysError (const char *method, const char *msgfmt,...) const
 Issue system error message. More...
 
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. More...
 
virtual void Warning (const char *method, const char *msgfmt,...) const
 Issue warning message. More...
 
virtual Int_t Write (const char *name=0, Int_t option=0, Int_t bufsize=0)
 Write this object to the current directory. More...
 
virtual Int_t Write (const char *name=0, Int_t option=0, Int_t bufsize=0) const
 Write this object to the current directory. More...
 

Private Member Functions

 TPluginManager (const TPluginManager &pm)
 true if we are running LoadHandlersFromPluginDirs More...
 
void LoadHandlerMacros (const char *path)
 Load all plugin macros from the specified path/base directory. More...
 
TPluginManageroperator= (const TPluginManager &pm)
 

Private Attributes

THashTablefBasesLoaded
 
TListfHandlers
 
Bool_t fReadingDirs
 table of base classes already checked or loaded More...
 

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. More...
 
static Bool_t GetObjectStat ()
 Get status of object stat flag. More...
 
static void SetDtorOnly (void *obj)
 Set destructor only flag. More...
 
static void SetObjectStat (Bool_t stat)
 Turn on/off tracking of objects in the TObjectTable. More...
 
- 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). More...
 
void MakeZombie ()
 

#include <TPluginManager.h>

Inheritance diagram for TPluginManager:
[legend]

Constructor & Destructor Documentation

◆ TPluginManager() [1/2]

TPluginManager::TPluginManager ( const TPluginManager pm)
private

true if we are running LoadHandlersFromPluginDirs

◆ TPluginManager() [2/2]

TPluginManager::TPluginManager ( )
inline

Definition at line 194 of file TPluginManager.h.

◆ ~TPluginManager()

TPluginManager::~TPluginManager ( )

Clean up the plugin manager.

Definition at line 337 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 529 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 581 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 391 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 351 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 450 of file TPluginManager.cxx.

◆ operator=()

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

◆ 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 611 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 558 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 641 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 725 of file TPluginManager.cxx.

Member Data Documentation

◆ fBasesLoaded

THashTable* TPluginManager::fBasesLoaded
private

Definition at line 186 of file TPluginManager.h.

◆ fHandlers

TList* TPluginManager::fHandlers
private

Definition at line 185 of file TPluginManager.h.

◆ fReadingDirs

Bool_t TPluginManager::fReadingDirs
private

table of base classes already checked or loaded

Definition at line 187 of file TPluginManager.h.


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