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Reference Guide
TPluginManager.h
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1// @(#)root/base:$Id$
2// Author: Fons Rademakers 26/1/2002
3
4/*************************************************************************
5 * Copyright (C) 1995-2002, Rene Brun and Fons Rademakers. *
6 * All rights reserved. *
7 * *
8 * For the licensing terms see $ROOTSYS/LICENSE. *
9 * For the list of contributors see $ROOTSYS/README/CREDITS. *
10 *************************************************************************/
11
12#ifndef ROOT_TPluginManager
13#define ROOT_TPluginManager
14
15
16//////////////////////////////////////////////////////////////////////////
17// //
18// TPluginManager //
19// //
20// This class implements a plugin library manager. It keeps track of //
21// a list of plugin handlers. A plugin handler knows which plugin //
22// library to load to get a specific class that is used to extend the //
23// functionality of a specific base class and how to create an object //
24// of this class. For example, to extend the base class TFile to be //
25// able to read SQLite files one needs to load the plugin library //
26// libRSQLite.so which defines the TSQLiteServer class. This loading //
27// should be triggered when a given URI contains a regular expression //
28// defined by the handler. //
29// Plugin handlers can be defined via macros in a list of plugin //
30// directories. With $ROOTSYS/etc/plugins the default top plugin //
31// directory specified in $ROOTSYS/etc/system.rootrc. Additional //
32// directories can be specified by adding them to the end of the list. //
33// Macros for identical plugin handlers in later directories will //
34// override previous ones (the inverse of normal search path behavior). //
35// The macros must have names like <BaseClass>/PX0_<PluginClass>.C, //
36// e.g.: //
37// TSQLServer/P20_TMySQLServer.C, etc. //
38// to allow easy sorting and grouping. If the BaseClass is in a //
39// namespace the directory must have the name NameSpace@@BaseClass as //
40// : is a reserved pathname character on some operating systems. //
41// Macros not beginning with 'P' and ending with ".C" are ignored. //
42// These macros typically look like: //
43// //
44// void P10_TDCacheFile() //
45// { //
46// gPluginMgr->AddHandler("TFile", "^dcache", "TDCacheFile", //
47// "DCache", "TDCacheFile(const char*,Option_t*)"); //
48// } //
49// //
50// Plugin handlers can also be defined via resources in the .rootrc //
51// file. Although now deprecated this method still works for backward //
52// compatibility, e.g.: //
53// //
54// Plugin.TSQLServer: ^mysql: TMySQLServer MySQL "<constructor>" //
55// +Plugin.TSQLServer: ^pgsql: TPgSQLServer PgSQL "<constructor>" //
56// Plugin.TVirtualFitter: * TFitter Minuit "TFitter(Int_t)" //
57// //
58// Where the + in front of Plugin.TSQLServer says that it extends the //
59// existing definition of TSQLServer, useful when there is more than //
60// one plugin that can extend the same base class. The "<constructor>" //
61// should be the constructor or a static method that generates an //
62// instance of the specified class. Global methods should start with //
63// "::" in their name, like "::CreateFitter()". //
64// Instead of being a shared library a plugin can also be a CINT //
65// script, so instead of libDialog.so one can have Dialog.C. //
66// The * is a placeholder in case there is no need for a URI to //
67// differentiate between different plugins for the same base class. //
68// For the default plugins see $ROOTSYS/etc/system.rootrc. //
69// //
70// Plugin handlers can also be registered at run time, e.g.: //
71// //
72// gPluginMgr->AddHandler("TSQLServer", "^sqlite:", //
73// "TSQLiteServer", "RSQLite", //
74// "TSQLiteServer(const char*,const char*,const char*)"); //
75// //
76// A list of currently defined handlers can be printed using: //
77// //
78// gPluginMgr->Print(); // use option="a" to see ctors //
79// //
80// The use of the plugin library manager removes all textual references //
81// to hard-coded class and library names and the resulting dependencies //
82// in the base classes. The plugin manager is used to extend a.o. //
83// TFile, TSQLServer, TGrid, etc. functionality. //
84// //
85//////////////////////////////////////////////////////////////////////////
86
87#include "TObject.h"
88#include "TString.h"
89#include "TMethodCall.h"
90#include "TVirtualMutex.h"
91#include "TInterpreter.h"
92
93class TEnv;
94class TList;
95class THashTable;
96class TFunction;
97class TPluginManager;
98
99#include <atomic>
100
101class TPluginHandler : public TObject {
102
103friend class TPluginManager;
104
105private:
106 using AtomicInt_t = std::atomic<Int_t>;
107
108 TString fBase; // base class which will be extended by plugin
109 TString fRegexp; // regular expression which must be matched in URI
110 TString fClass; // class to be loaded from plugin library
111 TString fPlugin; // plugin library which should contain fClass
112 TString fCtor; // ctor used to instantiate object of fClass
113 TString fOrigin; // origin of plugin handler definition
114 TMethodCall *fCallEnv; //!ctor method call environment
115 TFunction *fMethod; //!ctor method or global function
116 AtomicInt_t fCanCall; //!if 1 fCallEnv is ok, -1 fCallEnv is not ok, 0 fCallEnv not setup yet.
117 Bool_t fIsMacro; // plugin is a macro and not a library
118 Bool_t fIsGlobal; // plugin ctor is a global function
119
121 fBase(), fRegexp(), fClass(), fPlugin(), fCtor(), fOrigin(),
122 fCallEnv(nullptr), fMethod(nullptr), fCanCall(0), fIsMacro(kTRUE), fIsGlobal(kTRUE) { }
123 TPluginHandler(const char *base, const char *regexp,
124 const char *className, const char *pluginName,
125 const char *ctor, const char *origin);
128
130
131 const char *GetBase() const { return fBase; }
132 const char *GetRegexp() const { return fRegexp; }
133 const char *GetPlugin() const { return fPlugin; }
134 const char *GetCtor() const { return fCtor; }
135 const char *GetOrigin() const { return fOrigin; }
136
137 Bool_t CanHandle(const char *base, const char *uri);
138 void SetupCallEnv();
139
141
142public:
143 const char *GetClass() const { return fClass; }
144 Int_t CheckPlugin() const;
146
147 template <typename... T> Longptr_t ExecPluginImpl(const T&... params)
148 {
149 auto nargs = sizeof...(params);
150 if (!CheckForExecPlugin((Int_t)nargs)) return 0;
151
152 // The fCallEnv object is shared, since the PluginHandler is a global
153 // resource ... and both SetParams and Execute ends up taking the lock
154 // individually anyway ...
155
157 fCallEnv->SetParams(params...);
158
159 Longptr_t ret;
160 fCallEnv->Execute(ret);
161
162 return ret;
163 }
164
165 template <typename... T> Longptr_t ExecPlugin(int nargs, const T&... params)
166 {
167 // For backward compatibility.
168 if ((gDebug > 1) && (nargs != (int)sizeof...(params))) {
169 Warning("ExecPlugin","Announced number of args different from the real number of argument passed %d vs %lu",
170 nargs, (unsigned long)sizeof...(params) );
171 }
172 return ExecPluginImpl(params...);
173 }
174
175 void Print(Option_t *opt = "") const;
176
177 ClassDef(TPluginHandler,3) // Handler for plugin libraries
178};
179
180
181class TPluginManager : public TObject {
182
183private:
184 TList *fHandlers; // list of plugin handlers
185 THashTable *fBasesLoaded; //! table of base classes already checked or loaded
186 Bool_t fReadingDirs; //! true if we are running LoadHandlersFromPluginDirs
187
190 void LoadHandlerMacros(const char *path);
191
192public:
195
196 void LoadHandlersFromEnv(TEnv *env);
197 void LoadHandlersFromPluginDirs(const char *base = 0);
198 void AddHandler(const char *base, const char *regexp,
199 const char *className, const char *pluginName,
200 const char *ctor = 0, const char *origin = 0);
201 void RemoveHandler(const char *base, const char *regexp = 0);
202
203 TPluginHandler *FindHandler(const char *base, const char *uri = 0);
204
205 void Print(Option_t *opt = "") const;
206 Int_t WritePluginMacros(const char *dir, const char *plugin = 0) const;
207 Int_t WritePluginRecords(const char *envFile, const char *plugin = 0) const;
208
209 ClassDef(TPluginManager,1) // Manager for plugin handlers
210};
211
213
214#endif
#define R__EXTERN
Definition: DllImport.h:27
int Int_t
Definition: RtypesCore.h:45
long Longptr_t
Definition: RtypesCore.h:82
const Bool_t kFALSE
Definition: RtypesCore.h:101
bool Bool_t
Definition: RtypesCore.h:63
const Bool_t kTRUE
Definition: RtypesCore.h:100
const char Option_t
Definition: RtypesCore.h:66
#define ClassDef(name, id)
Definition: Rtypes.h:325
R__EXTERN TVirtualMutex * gInterpreterMutex
Definition: TInterpreter.h:44
R__EXTERN TPluginManager * gPluginMgr
Int_t gDebug
Definition: TROOT.cxx:592
#define R__LOCKGUARD(mutex)
The TEnv class reads config files, by default named .rootrc.
Definition: TEnv.h:124
Global functions class (global functions are obtained from CINT).
Definition: TFunction.h:30
THashTable implements a hash table to store TObject's.
Definition: THashTable.h:35
A doubly linked list.
Definition: TList.h:44
Method or function calling interface.
Definition: TMethodCall.h:37
void SetParams(const T &... params)
Definition: TMethodCall.h:104
void Execute(const char *, const char *, int *=0)
Execute method on this object with the given parameter string, e.g.
Definition: TMethodCall.h:64
Mother of all ROOT objects.
Definition: TObject.h:37
virtual void Warning(const char *method, const char *msgfmt,...) const
Issue warning message.
Definition: TObject.cxx:879
const char * GetClass() const
Int_t CheckPlugin() const
Check if the plugin library for this handler exits.
void Print(Option_t *opt="") const
Print info about the plugin handler.
TFunction * fMethod
ctor method call environment
AtomicInt_t fCanCall
ctor method or global function
const char * GetOrigin() const
std::atomic< Int_t > AtomicInt_t
Bool_t CanHandle(const char *base, const char *uri)
Check if regular expression appears in the URI, if so return kTRUE.
TPluginHandler(const TPluginHandler &)=delete
const char * GetRegexp() const
const char * GetBase() const
~TPluginHandler()
Cleanup plugin handler object.
Bool_t CheckForExecPlugin(Int_t nargs)
Check that we can properly run ExecPlugin.
Longptr_t ExecPlugin(int nargs, const T &... params)
const char * GetPlugin() const
Bool_t fIsMacro
if 1 fCallEnv is ok, -1 fCallEnv is not ok, 0 fCallEnv not setup yet.
void SetupCallEnv()
Setup ctor or static method call environment.
Longptr_t ExecPluginImpl(const T &... params)
TMethodCall * fCallEnv
TPluginHandler & operator=(const TPluginHandler &)=delete
const char * GetCtor() const
Int_t LoadPlugin()
Load the plugin library for this handler.
This class implements a plugin library manager.
void LoadHandlersFromPluginDirs(const char *base=0)
Load plugin handlers specified via macros in a list of plugin directories.
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.
~TPluginManager()
Clean up the plugin manager.
TPluginManager(const TPluginManager &)=delete
true if we are running LoadHandlersFromPluginDirs
TPluginHandler * FindHandler(const char *base, const char *uri=0)
Returns the handler if there exists a handler for the specified URI.
void Print(Option_t *opt="") const
Print list of registered plugin handlers.
void LoadHandlersFromEnv(TEnv *env)
Load plugin handlers specified in config file, like:
Bool_t fReadingDirs
table of base classes already checked or loaded
void RemoveHandler(const char *base, const char *regexp=0)
Remove handler for the specified base class and the specified regexp.
TPluginManager & operator=(const TPluginManager &)=delete
THashTable * fBasesLoaded
void LoadHandlerMacros(const char *path)
Load all plugin macros from the specified path/base directory.
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.
Basic string class.
Definition: TString.h:136
double T(double x)
Definition: ChebyshevPol.h:34