TFolder.cxx

Go to the documentation of this file.

// @(#)root/base:$Id$
// Author: Rene Brun   02/09/2000
 
/*************************************************************************
 * Copyright (C) 1995-2000, Rene Brun and Fons Rademakers.               *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/CREDITS.             *
 *************************************************************************/
 
 
/** \class TFolder
\ingroup Base
 
\legacy{TFolder}
 
A TFolder object is a collection of objects and folders.
Folders have a name and a title and are identified in the folder hierarchy
by a "Unix-like" naming mechanism. The root of all folders is //root.
New folders can be dynamically added or removed to/from a folder.
The folder hierarchy can be visualized via the TBrowser.
 
\image html base_browser.png
 
The Root folders hierarchy can be seen as a whiteboard where objects
are posted. Other classes/tasks can access these objects by specifying
only a string pathname. This whiteboard facility greatly improves the
modularity of an application, minimizing the class relationship problem
that penalizes large applications.
 
Pointers are efficient to communicate between classes.
However, one has interest to minimize direct coupling between classes
in the form of direct pointers. One better uses the naming and search
service provided by the Root folders hierarchy. This makes the classes
loosely coupled and also greatly facilitates I/O operations.
In a client/server environment, this mechanism facilitates the access
to any kind of object in //root stores running on different processes.
 
A TFolder is created by invoking the TFolder constructor. It is placed
inside an existing folder via the TFolder::AddFolder method.
One can search for a folder or an object in a folder using the FindObject
method. FindObject analyses the string passed as its argument and searches
in the hierarchy until it finds an object or folder matching the name.
 
When a folder is deleted, its reference from the parent folder and
possible other folders is deleted.
 
If a folder has been declared the owner of its objects/folders via
TFolder::SetOwner, then the contained objects are deleted when the
folder is deleted. By default, a folder does not own its contained objects.
 
NOTE that folder ownership can be set
  - via TFolder::SetOwner
  - or via TCollection::SetOwner on the collection specified to TFolder::AddFolder
 
Standard Root objects are automatically added to the folder hierarchy.
For example, the following folders exist:
  //root/Files      with the list of currently connected Root files
  //root/Classes    with the list of active classes
  //root/Geometries with active geometries
  //root/Canvases   with the list of active canvases
  //root/Styles     with the list of graphics styles
  //root/Colors     with the list of active colors
 
For example, if a file "myFile.root" is added to the list of files, one can
retrieve a pointer to the corresponding TFile object with a statement like:
~~~ {.cpp}
  TFile *myFile = (TFile*)gROOT->FindObject("//root/Files/myFile.root");
~~~
The above statement can be abbreviated to:
~~~ {.cpp}
  TFile *myFile = (TFile*)gROOT->FindObject("/Files/myFile.root");
~~~
or even to:
~~~ {.cpp}
  TFile *myFile = (TFile*)gROOT->FindObjectAny("myFile.root");
~~~
In this last case, the TROOT::FindObjectAny function will scan the folder hierarchy
starting at //root and will return the first object named "myFile.root".
 
Because a string-based search mechanism is expensive, it is recommended
to save the pointer to the object as a class member or local variable
if this pointer is used frequently or inside loops.
*/
 
#include <iostream>
#include "Strlen.h"
#include "strlcpy.h"
#include "TFolder.h"
#include "TBrowser.h"
#include "TList.h"
#include "TROOT.h"
#include "TClass.h"
#include "TError.h"
#include "TRegexp.h"
 
static const char *gFolderD[64];
static Int_t gFolderLevel = -1;
static char  gFolderPath[512];
 
enum { kOwnFolderList = BIT(15) };
 
 
////////////////////////////////////////////////////////////////////////////////
/// Default constructor used by the Input functions.
///
/// This constructor should not be called by a user directly.
/// The normal way to create a folder is by calling TFolder::AddFolder.
 
TFolder::TFolder() : TNamed()
{
   fFolders = nullptr;
   fIsOwner = kFALSE;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Create a normal folder.
/// Use Add or AddFolder to add objects or folders to this folder.
 
TFolder::TFolder(const char *name, const char *title) : TNamed(name,title)
{
   fFolders = new TList();
   SetBit(kOwnFolderList);
   fIsOwner = kFALSE;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Folder destructor. Remove all objects from its lists and delete
/// all its sub folders.
 
TFolder::~TFolder()
{
   TCollection::StartGarbageCollection();
 
   if (fFolders) {
      if (fFolders->IsOwner()) {
         fFolders->Delete();
      }
      if (TestBit(kOwnFolderList)) {
         TObjLink *iter = ((TList*)fFolders)->FirstLink();
         while (iter) {
            TObject *obj = iter->GetObject();
            TObjLink *next = iter->Next();
            if (obj && obj->IsA() == TFolder::Class()) {
               ((TList*)fFolders)->Remove(iter);
               delete obj;
            }
            iter = next;
         }
         fFolders->Clear("nodelete");
         SafeDelete(fFolders);
      }
   }
 
   TCollection::EmptyGarbageCollection();
 
   if (gDebug)
      std::cerr << "TFolder dtor called for "<< GetName() << std::endl;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Add object to this folder. obj must be a TObject or a TFolder.
 
void TFolder::Add(TObject *obj)
{
   if (obj == nullptr || fFolders == nullptr) return;
   obj->SetBit(kMustCleanup);
   fFolders->Add(obj);
}
 
////////////////////////////////////////////////////////////////////////////////
/// Create a new folder and add it to the list of folders of this folder,
/// return a pointer to the created folder.
/// Note that a folder can be added to several folders.
///
/// If collection is non NULL, the pointer fFolders is set to the existing
/// collection, otherwise a default collection (Tlist) is created.
/// Note that the folder name cannot contain slashes.
 
TFolder *TFolder::AddFolder(const char *name, const char *title, TCollection *collection)
{
   if (strchr(name,'/')) {
      ::Error("TFolder::TFolder","folder name cannot contain a slash: %s", name);
      return nullptr;
   }
   if (strlen(GetName()) == 0) {
      ::Error("TFolder::TFolder","folder name cannot be \"\"");
      return nullptr;
   }
   TFolder *folder = new TFolder();
   folder->SetName(name);
   folder->SetTitle(title);
   if (!fFolders) {
      fFolders = new TList(); //only true when gROOT creates its 1st folder
      SetBit(kOwnFolderList);
   }
   fFolders->Add(folder);
 
   if (collection) {
      folder->fFolders = collection;
   } else {
      folder->fFolders = new TList();
      folder->SetBit(kOwnFolderList);
   }
   return folder;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Browse this folder.
 
void TFolder::Browse(TBrowser *b)
{
   if (fFolders) fFolders->Browse(b);
}
 
////////////////////////////////////////////////////////////////////////////////
/// Delete all objects from a folder list.
 
void TFolder::Clear(Option_t *option)
{
   if (fFolders) fFolders->Clear(option);
}
 
////////////////////////////////////////////////////////////////////////////////
/// Return the full pathname corresponding to subpath name if the node is
/// gROOT->GetRootFolder() and return a relative path otherwise.
/// The returned path will be re-used by the next call to FindFullPathName().
 
const char *TFolder::FindFullPathName(const char *name) const
{
   TObject *obj = FindObject(name);
   if (obj || !fFolders) {
      gFolderLevel++;
      gFolderD[gFolderLevel] = GetName();
      if (strcmp(gFolderD[0],"root")==0) {
         strlcpy(gFolderPath,"//root/", sizeof(gFolderPath));
      } else {
         gFolderPath[0] = '\0';
      }
      for (Int_t l = 1; l<=gFolderLevel;l++) {
         strlcat(gFolderPath, gFolderD[l], sizeof(gFolderPath));
         strlcat(gFolderPath, "/", sizeof(gFolderPath));
      }
      strlcat(gFolderPath,name, sizeof(gFolderPath));
      gFolderLevel = -1;
      return gFolderPath;
   }
   if (name[0] == '/') return nullptr;
   TIter next(fFolders);
   TFolder *folder;
   const char *found;
   gFolderLevel++;
   gFolderD[gFolderLevel] = GetName();
   while ((obj=next())) {
      // For a TClass object, InheritsFrom does not check the inheritance of
      // the object but the inheritance of the class described by the object,
      // so we need to explicitly call IsA
      if (obj->IsA()->InheritsFrom(TClass::Class())) continue;
      // For any other object IsA is called by InheritsFrom
      if (!obj->InheritsFrom(TFolder::Class())) continue;
      folder = (TFolder*)obj;
      found = folder->FindFullPathName(name);
      if (found) return found;
   }
   gFolderLevel--;
   return nullptr;
}
 
 
////////////////////////////////////////////////////////////////////////////////
/// Return the full pathname corresponding to subpath name.
/// The returned path will be re-used by the next call to FindFullPathName().
 
const char *TFolder::FindFullPathName(const TObject *) const
{
   Error("FindFullPathname","Not yet implemented");
   return nullptr;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Find object in an folder.
 
TObject *TFolder::FindObject(const TObject *) const
{
   Error("FindObject","Not yet implemented");
   return nullptr;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Search object identified by name in the tree of folders inside
/// this folder.
/// Name may be of the forms:
///
///   A. Specify a full pathname starting at the top ROOT folder
///     //root/xxx/yyy/name
///
///   B. Specify a pathname starting with a single slash. //root is assumed
///     /xxx/yyy/name
///
///   C. Specify a pathname relative to this folder
///      xxx/yyy/name
///      name
 
TObject *TFolder::FindObject(const char *name) const
{
   if (!fFolders || !name) return nullptr;
   if (name[0] == '/') {
      if (name[1] == '/') {
         if (!strstr(name,"//root/")) return nullptr;
         return gROOT->GetRootFolder()->FindObject(name+7);
      } else {
         return gROOT->GetRootFolder()->FindObject(name+1);
      }
   }
   Int_t nch = strlen(name);
   char csname[128];
   char *cname = csname;
   Int_t len = sizeof(csname);
   if (nch >= len) {
      len = nch+1;
      cname = new char[len];
   }
   strlcpy(cname, name, len);
   TObject *ret = nullptr;
   char *slash = strchr(cname,'/');
   if (slash) {
      *slash = 0;
      if (TObject *obj = fFolders->FindObject(cname))
         ret = obj->FindObject(slash+1);
   } else {
      ret = fFolders->FindObject(cname);
   }
   if (cname != csname)
      delete [] cname;
   return ret;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Return a pointer to the first object with name starting at this folder.
 
TObject *TFolder::FindObjectAny(const char *name) const
{
   TObject *obj = FindObject(name);
   if (obj || !fFolders) return obj;
 
   //if (!obj->InheritsFrom(TFolder::Class())) continue;
   if (name[0] == '/') return nullptr;
   TIter next(fFolders);
   TFolder *folder;
   TObject *found;
   if (gFolderLevel >= 0) gFolderD[gFolderLevel] = GetName();
   while ((obj=next())) {
      if (!obj->InheritsFrom(TFolder::Class())) continue;
      if (obj->IsA() == TClass::Class()) continue;
      folder = (TFolder*)obj;
      found = folder->FindObjectAny(name);
      if (found) return found;
   }
   return nullptr;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Folder ownership has been set via
///   - TFolder::SetOwner
///   - TCollection::SetOwner on the collection specified to TFolder::AddFolder
 
Bool_t TFolder::IsOwner()  const
{
   if (!fFolders) return kFALSE;
   return fFolders->IsOwner();
}
 
////////////////////////////////////////////////////////////////////////////////
/// List folder contents.
///
///   If option contains "dump",  the Dump function of contained objects is called.
///
///   If option contains "print", the Print function of contained objects is called.
///
///   By default the ls function of contained objects is called.
///
/// Indentation is used to identify the folder tree.
///
/// The if option contains a `<regexp>` it be used to match the name of the objects.
 
void TFolder::ls(Option_t *option) const
{
   if (!fFolders) return;
   TROOT::IndentLevel();
   std::cout <<ClassName()<<"*\t\t"<<GetName()<<"\t"<<GetTitle()<<std::endl;
   TROOT::IncreaseDirLevel();
 
   TString opt = option;
   Ssiz_t dump = opt.Index("dump", 0, TString::kIgnoreCase);
   if (dump != kNPOS)
      opt.Remove(dump, 4);
   Ssiz_t print = opt.Index("print", 0, TString::kIgnoreCase);
   if (print != kNPOS)
      opt.Remove(print, 5);
   opt = opt.Strip(TString::kBoth);
   if (opt == "")
      opt = "*";
   TRegexp re(opt, kTRUE);
 
   TObject *obj;
   TIter nextobj(fFolders);
   while ((obj = (TObject *) nextobj())) {
      TString s = obj->GetName();
      if (s.Index(re) == kNPOS) continue;
      if (dump != kNPOS)
         obj->Dump();
      if (print != kNPOS)
         obj->Print(option);
      obj->ls(option);
   }
   TROOT::DecreaseDirLevel();
}
 
////////////////////////////////////////////////////////////////////////////////
/// Return occurence number of object in the list of objects of this folder.
/// The function returns the number of objects with the same name as object
/// found in the list of objects in this folder before object itself.
/// If only one object is found, return 0.
 
Int_t TFolder::Occurence(const TObject *object) const
{
   Int_t n = 0;
   if (!fFolders) return 0;
   TIter next(fFolders);
   TObject *obj;
   while ((obj=next())) {
      if (strcmp(obj->GetName(),object->GetName()) == 0) n++;
   }
   if (n <=1) return n-1;
   n = 0;
   next.Reset();
   while ((obj=next())) {
      if (strcmp(obj->GetName(),object->GetName()) == 0) n++;
      if (obj == object) return n;
   }
   return 0;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Recursively remove object from a folder.
 
void TFolder::RecursiveRemove(TObject *obj)
{
   if (fFolders) fFolders->RecursiveRemove(obj);
}
 
////////////////////////////////////////////////////////////////////////////////
/// Remove object from this folder. obj must be a TObject or a TFolder.
 
void TFolder::Remove(TObject *obj)
{
   if (obj == nullptr || fFolders == nullptr) return;
   fFolders->Remove(obj);
}
 
////////////////////////////////////////////////////////////////////////////////
/// Save all objects in this folder in filename.
/// Each object in this folder will have a key in the file where the name of
/// the key will be the name of the object.
 
void TFolder::SaveAs(const char *filename, Option_t *option) const
{
   if (gDirectory) gDirectory->SaveObjectAs(this,filename,option);
}
 
////////////////////////////////////////////////////////////////////////////////
/// Set ownership.
/// If the folder is declared owner, when the folder is deleted, all
/// the objects added via TFolder::Add are deleted via TObject::Delete,
/// otherwise TObject::Clear is called.
///
/// NOTE that folder ownership can be set:
///   - via TFolder::SetOwner
///   - or via TCollection::SetOwner on the collection specified to TFolder::AddFolder
 
void TFolder::SetOwner(Bool_t owner)
{
   if (!fFolders) fFolders = new TList();
   fFolders->SetOwner(owner);
}