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TTreeReader.cxx
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1// @(#)root/treeplayer:$Id$
2// Author: Axel Naumann, 2011-09-21
3
4/*************************************************************************
5 * Copyright (C) 1995-2013, Rene Brun and Fons Rademakers and al. *
6 * All rights reserved. *
7 * *
8 * For the licensing terms see $ROOTSYS/LICENSE. *
9 * For the list of contributors see $ROOTSYS/README/CREDITS. *
10 *************************************************************************/
11
12#include "TTreeReader.h"
13
14#include "TChain.h"
15#include "TDirectory.h"
16#include "TEntryList.h"
17#include "TTreeCache.h"
18#include "TTreeReaderValue.h"
19#include "TFriendProxy.h"
20
21
22// clang-format off
23/**
24 \class TTreeReader
25 \ingroup treeplayer
26 \brief A simple, robust and fast interface to read values from ROOT columnar datasets such as TTree, TChain or TNtuple
27
28 TTreeReader is associated to TTreeReaderValue and TTreeReaderArray which are handles to concretely
29 access the information in the dataset.
30
31 Example code can be found in
32 - tutorials/tree/hsimpleReader.C
33 - tutorials/tree/h1analysisTreeReader.C
34 - <a href="https://github.com/root-project/roottest/tree/master/root/tree/reader">This example</a>
35
36 You can generate a skeleton of `TTreeReaderValue<T>` and `TTreeReaderArray<T>` declarations
37 for all of a tree's branches using `TTree::MakeSelector()`.
38
39 Roottest contains an
40 <a href="https://github.com/root-project/roottest/tree/master/root/tree/reader">example</a>
41 showing the full power.
42
43A simpler analysis example can be found below: it histograms a function of the px and py branches.
44
45~~~{.cpp}
46// A simple TTreeReader use: read data from hsimple.root (written by hsimple.C)
47
48#include "TFile.h"
49#include "TH1F.h"
50#include "TTreeReader.h"
51#include "TTreeReaderValue.h"
52
53void hsimpleReader() {
54 // Create a histogram for the values we read.
55 TH1F("h1", "ntuple", 100, -4, 4);
56
57 // Open the file containing the tree.
58 TFile *myFile = TFile::Open("$ROOTSYS/tutorials/hsimple.root");
59
60 // Create a TTreeReader for the tree, for instance by passing the
61 // TTree's name and the TDirectory / TFile it is in.
62 TTreeReader myReader("ntuple", myFile);
63
64 // The branch "px" contains floats; access them as myPx.
65 TTreeReaderValue<Float_t> myPx(myReader, "px");
66 // The branch "py" contains floats, too; access those as myPy.
67 TTreeReaderValue<Float_t> myPy(myReader, "py");
68
69 // Loop over all entries of the TTree or TChain.
70 while (myReader.Next()) {
71 // Just access the data as if myPx and myPy were iterators (note the '*'
72 // in front of them):
73 myHist->Fill(*myPx + *myPy);
74 }
75
76 myHist->Draw();
77}
78~~~
79
80A more complete example including error handling and a few combinations of
81TTreeReaderValue and TTreeReaderArray would look like this:
82
83~~~{.cpp}
84#include <TFile.h>
85#include <TH1.h>
86#include <TTreeReader.h>
87#include <TTreeReaderValue.h>
88#include <TTreeReaderArray.h>
89
90#include "TriggerInfo.h"
91#include "Muon.h"
92#include "Tau.h"
93
94#include <vector>
95#include <iostream>
96
97bool CheckValue(ROOT::Internal::TTreeReaderValueBase& value) {
98 if (value.GetSetupStatus() < 0) {
99 std::cerr << "Error " << value.GetSetupStatus()
100 << "setting up reader for " << value.GetBranchName() << '\n';
101 return false;
102 }
103 return true;
104}
105
106
107// Analyze the tree "MyTree" in the file passed into the function.
108// Returns false in case of errors.
109bool analyze(TFile* file) {
110 // Create a TTreeReader named "MyTree" from the given TDirectory.
111 // The TTreeReader gives access to the TTree to the TTreeReaderValue and
112 // TTreeReaderArray objects. It knows the current entry number and knows
113 // how to iterate through the TTree.
114 TTreeReader reader("MyTree", file);
115
116 // Read a single float value in each tree entries:
117 TTreeReaderValue<float> weight(reader, "event.weight");
118
119 // Read a TriggerInfo object from the tree entries:
120 TTreeReaderValue<TriggerInfo> triggerInfo(reader, "triggerInfo");
121
122 //Read a vector of Muon objects from the tree entries:
123 TTreeReaderValue<std::vector<Muon>> muons(reader, "muons");
124
125 //Read the pT for all jets in the tree entry:
126 TTreeReaderArray<double> jetPt(reader, "jets.pT");
127
128 // Read the taus in the tree entry:
129 TTreeReaderArray<Tau> taus(reader, "taus");
130
131
132 // Now iterate through the TTree entries and fill a histogram.
133
134 TH1F("hist", "TTreeReader example histogram", 10, 0., 100.);
135
136 bool firstEntry = true;
137 while (reader.Next()) {
138 if (firstEntry) {
139 // Check that branches exist and their types match our expectation.
140 if (!CheckValue(weight)) return false;
141 if (!CheckValue(triggerInfo)) return false;
142 if (!CheckValue(muons)) return false;
143 if (!CheckValue(jetPt)) return false;
144 if (!CheckValue(taus)) return false;
145 firstentry = false;
146 }
147
148 // Access the TriggerInfo object as if it's a pointer.
149 if (!triggerInfo->hasMuonL1())
150 continue;
151
152 // Ditto for the vector<Muon>.
153 if (!muons->size())
154 continue;
155
156 // Access the jetPt as an array, whether the TTree stores this as
157 // a std::vector, std::list, TClonesArray or Jet* C-style array, with
158 // fixed or variable array size.
159 if (jetPt.GetSize() < 2 || jetPt[0] < 100)
160 continue;
161
162 // Access the array of taus.
163 if (!taus.IsEmpty()) {
164 // Access a float value - need to dereference as TTreeReaderValue
165 // behaves like an iterator
166 float currentWeight = *weight;
167 for (const Tau& tau: taus) {
168 hist->Fill(tau.eta(), currentWeight);
169 }
170 }
171 } // TTree entry / event loop
172
173 // Return true if we have iterated through all entries.
174 return reader.GetEntryStatus() == TTreeReader::kEntryBeyondEnd;
175}
176~~~
177*/
178// clang-format on
179
181
182using namespace ROOT::Internal;
183
184// Provide some storage for the poor little symbol.
186
187////////////////////////////////////////////////////////////////////////////////
188/// Default constructor. Call SetTree to connect to a TTree.
189
190TTreeReader::TTreeReader() : fNotify(this) {}
191
192////////////////////////////////////////////////////////////////////////////////
193/// Access data from tree.
194///
195/// \param tree The TTree or TChain to read from
196/// \param entryList It can be a single TEntryList with global entry numbers (supported, as
197/// an extension, also in the case of a TChain) or, if the first parameter
198/// is a TChain, a TEntryList with sub-TEntryLists with local entry numbers.
199/// In the latter case, the TEntryList must be associated to the TChain, as
200/// per chain.SetEntryList(&entryList).
201
202TTreeReader::TTreeReader(TTree* tree, TEntryList* entryList /*= nullptr*/):
203 fTree(tree),
204 fEntryList(entryList),
205 fNotify(this)
206{
207 if (!fTree) {
208 ::Error("TTreeReader::TTreeReader", "TTree is NULL!");
209 } else {
210 Initialize();
211 }
212}
213
214////////////////////////////////////////////////////////////////////////////////
215/// Access data from the tree called keyname in the directory (e.g. TFile)
216/// dir, or the current directory if dir is NULL. If keyname cannot be
217/// found, or if it is not a TTree, IsInvalid() will return true.
218///
219/// \param keyname The name of the TTree to read from file
220/// \param dir The TDirectory to read keyname from
221/// \param entryList It can be a single TEntryList with global entry numbers (supported, as
222/// an extension, also in the case of a TChain) or, if the first parameter
223/// is a TChain, a TEntryList with sub-TEntryLists with local entry numbers.
224/// In the latter case, the TEntryList must be associated to the TChain, as
225/// per chain.SetEntryList(&entryList).
226
227TTreeReader::TTreeReader(const char* keyname, TDirectory* dir, TEntryList* entryList /*= nullptr*/):
228 fEntryList(entryList),
229 fNotify(this)
230{
231 if (!dir) dir = gDirectory;
232 dir->GetObject(keyname, fTree);
233 if (!fTree) {
234 std::string msg = "No TTree called ";
235 msg += keyname;
236 msg += " was found in the selected TDirectory.";
237 Error("TTreeReader", "%s", msg.c_str());
238 }
239 Initialize();
240}
241
242////////////////////////////////////////////////////////////////////////////////
243/// Tell all value readers that the tree reader does not exist anymore.
244
246{
247 for (std::deque<ROOT::Internal::TTreeReaderValueBase*>::const_iterator
248 i = fValues.begin(), e = fValues.end(); i != e; ++i) {
249 (*i)->MarkTreeReaderUnavailable();
250 }
251 if (fTree && fNotify.IsLinked())
253
254 // Need to clear the map of proxies before deleting the director otherwise
255 // they will have a dangling pointer.
256 fProxies.clear();
257
258 for (auto feproxy: fFriendProxies) {
259 delete feproxy;
260 }
261 fFriendProxies.clear();
262
263 delete fDirector;
264}
265
266////////////////////////////////////////////////////////////////////////////////
267/// Initialization of the director.
268
270{
271 fEntry = -1;
272 if (!fTree) {
275 return;
276 }
277
281 } else if (fEntryList && fEntryList->GetLists()) {
282 Error("Initialize", "We are not processing a TChain but the TEntryList contains sublists. Please "
283 "provide a simple TEntryList with no sublists instead.");
286 return;
287 }
288
290
291 if (!fNotify.IsLinked()) {
293
294 if (fTree->GetTree()) {
295 // The current TTree is already available.
297 Notify();
299 }
300 }
301}
302
303////////////////////////////////////////////////////////////////////////////////
304/// Notify director and values of a change in tree. Called from TChain and TTree's LoadTree.
305/// TTreeReader registers its fNotify data member with the TChain/TTree which
306/// in turn leads to this method being called upon the execution of LoadTree.
308{
309
312 // This can happen if someone switched trees behind us.
313 // Likely cause: a TChain::LoadTree() e.g. from TTree::Process().
314 // This means that "local" should be set!
315 // There are two entities switching trees which is bad.
316 Warning("SetEntryBase()",
317 "The current tree in the TChain %s has changed (e.g. by TTree::Process) "
318 "even though TTreeReader::SetEntry() was called, which switched the tree "
319 "again. Did you mean to call TTreeReader::SetLocalEntry()?",
320 fTree->GetName());
321 }
323 } else {
325 }
326
328 Warning("SetEntryBase()",
329 "The TTree / TChain has an associated TEntryList. "
330 "TTreeReader ignores TEntryLists unless you construct the TTreeReader passing a TEntryList.");
332 }
333
334 if (!fDirector->Notify()) {
335 Error("SetEntryBase()", "There was an error while notifying the proxies.");
336 return false;
337 }
338
339 if (fProxiesSet) {
340 for (auto value: fValues) {
341 value->NotifyNewTree(fTree->GetTree());
342 }
343 }
344
345 return true;
346}
347
348////////////////////////////////////////////////////////////////////////////////
349/// Tell readers we now have a tree.
350/// fValues gets insertions during this loop (when parametrized arrays are read),
351/// invalidating iterators. Use old-school counting instead.
352
354
355 for (size_t i = 0; i < fValues.size(); ++i) {
357 reader->CreateProxy();
358 if (!reader->GetProxy()){
359 return false;
360 }
361
362 }
363 // If at least one proxy was there and no error occurred, we assume the proxies to be set.
364 fProxiesSet = !fValues.empty();
365
366 // Now we need to properly set the TTreeCache. We do this in steps:
367 // 1. We set the entry range according to the entry range of the TTreeReader
368 // 2. We add to the cache the branches identifying them by the name the user provided
369 // upon creation of the TTreeReader{Value, Array}s
370 // 3. We stop the learning phase.
371 // Operations 1, 2 and 3 need to happen in this order. See: https://sft.its.cern.ch/jira/browse/ROOT-9773?focusedCommentId=87837
372 if (fProxiesSet) {
373 const auto curFile = fTree->GetCurrentFile();
374 if (curFile && fTree->GetTree()->GetReadCache(curFile, true)) {
375 if (!(-1LL == fEndEntry && 0ULL == fBeginEntry)) {
376 // We need to avoid to pass -1 as end entry to the SetCacheEntryRange method
377 const auto lastEntry = (-1LL == fEndEntry) ? fTree->GetEntriesFast() : fEndEntry;
379 }
380 for (auto value: fValues) {
381 fTree->AddBranchToCache(value->GetProxy()->GetBranchName(), true);
382 }
384 }
385 }
386
387 return true;
388}
389
390////////////////////////////////////////////////////////////////////////////////
391/// Set the range of entries to be loaded by `Next()`; end will not be loaded.
392///
393/// If end <= begin, `end` is ignored (set to `-1`, i.e. will run on all entries from `begin` onwards).
394///
395/// Example:
396///
397/// ~~~ {.cpp}
398/// reader.SetEntriesRange(3, 5);
399/// while (reader.Next()) {
400/// // Will load entries 3 and 4.
401/// }
402/// ~~~
403///
404/// Note that if a TEntryList is present, beginEntry and endEntry refer to the beginEntry-th/endEntry-th entries of the
405/// TEntryList (or the main TEntryList in case it has sub-entrylists). In other words, SetEntriesRange can
406/// be used to only loop over part of the TEntryList, but not to further restrict the actual TTree/TChain entry numbers
407/// considered.
408///
409/// \param beginEntry The first entry to be loaded by `Next()`.
410/// \param endEntry The entry where `Next()` will return false, not loading it.
411
413{
414 if (beginEntry < 0)
415 return kEntryNotFound;
416 // Complain if the entries number is larger than the tree's / chain's / entry
417 // list's number of entries, unless it's a TChain and "max entries" is
418 // uninitialized (i.e. TTree::kMaxEntries).
419 if (beginEntry >= GetEntries(false) && !(IsChain() && GetEntries(false) == TTree::kMaxEntries)) {
420 Error("SetEntriesRange()", "Start entry (%lld) must be lower than the available entries (%lld).", beginEntry,
421 GetEntries(false));
422 return kEntryNotFound;
423 }
424
425 // Update data members to correctly reflect the defined range
426 if (endEntry > beginEntry)
427 fEndEntry = endEntry;
428 else
429 fEndEntry = -1;
430
431 fBeginEntry = beginEntry;
432
433 if (beginEntry - 1 < 0)
434 // Reset the cache if reading from the first entry of the tree
435 Restart();
436 else {
437 // Load the first entry in the range. SetEntry() will also call SetProxies(),
438 // thus adding all the branches to the cache and triggering the learning phase.
439 EEntryStatus es = SetEntry(beginEntry - 1);
440 if (es != kEntryValid) {
441 Error("SetEntriesRange()", "Error setting first entry %lld: %s",
442 beginEntry, fgEntryStatusText[(int)es]);
443 return es;
444 }
445 }
446
447 return kEntryValid;
448}
449
452 fProxiesSet = false; // we might get more value readers, meaning new proxies.
453 fEntry = -1;
454 if (const auto curFile = fTree->GetCurrentFile()) {
455 if (auto tc = fTree->GetTree()->GetReadCache(curFile, true)) {
456 tc->DropBranch("*", true);
457 tc->ResetCache();
458 }
459 }
460}
461
462////////////////////////////////////////////////////////////////////////////////
463/// Returns the number of entries of the TEntryList if one is provided, else
464/// of the TTree / TChain, independent of a range set by SetEntriesRange()
465/// by calling TTree/TChain::%GetEntriesFast.
466
467
469 if (fEntryList)
470 return fEntryList->GetN();
471 if (!fTree)
472 return -1;
473 return fTree->GetEntriesFast();
474}
475
476
477////////////////////////////////////////////////////////////////////////////////
478/// Returns the number of entries of the TEntryList if one is provided, else
479/// of the TTree / TChain, independent of a range set by SetEntriesRange().
480///
481/// \param force If `IsChain()` and `force`, determines whether all TFiles of
482/// this TChain should be opened to determine the exact number of entries
483/// of the TChain. If `!IsChain()`, `force` is ignored.
484
486 if (fEntryList)
487 return fEntryList->GetN();
488 if (!fTree)
489 return -1;
490 if (force) {
492 auto res = fTree->GetEntries();
493 // Go back to where we were:
496 return res;
497 }
498 return fTree->GetEntriesFast();
499}
500
501
502
503////////////////////////////////////////////////////////////////////////////////
504/// Load an entry into the tree, return the status of the read.
505/// For chains, entry is the global (i.e. not tree-local) entry number, unless
506/// `local` is `true`, in which case `entry` specifies the entry number within
507/// the current tree. This is needed for instance for TSelector::Process().
508
510{
511 if (IsInvalid()) {
513 fEntry = -1;
514 return fEntryStatus;
515 }
516
517 fEntry = entry;
518
519 Long64_t entryAfterList = entry;
520 if (fEntryList) {
521 if (entry >= fEntryList->GetN()) {
522 // Passed the end of the chain, Restart() was not called:
523 // don't try to load entries anymore. Can happen in these cases:
524 // while (tr.Next()) {something()};
525 // while (tr.Next()) {somethingelse()}; // should not be calling somethingelse().
527 return fEntryStatus;
528 }
529 if (entry >= 0) {
530 if (fEntryList->GetLists()) {
532 int treenum = -1;
533 entryAfterList = fEntryList->GetEntryAndTree(entry, treenum);
534 entryAfterList += static_cast<TChain *>(fTree)->GetTreeOffset()[treenum];
535 // We always translate local entry numbers to global entry numbers for TChain+TEntryList with sublists
536 local = false;
537 } else {
538 // Could be a TTree or a TChain (TTreeReader also supports single TEntryLists for TChains).
539 // In both cases, we are using the global entry numbers coming from the single TEntryList.
540 entryAfterList = fEntryList->GetEntry(entry);
541 }
542 }
543 }
544
545 TTree* treeToCallLoadOn = local ? fTree->GetTree() : fTree;
546
548 const Long64_t loadResult = treeToCallLoadOn->LoadTree(entryAfterList);
550
551 if (loadResult < 0) {
552 // ROOT-9628 We cover here the case when:
553 // - We deal with a TChain
554 // - The last file is opened
555 // - The TTree is not correctly loaded
556 // The system is robust against issues with TTrees associated to the chain
557 // when they are not at the end of it.
558 if (loadResult == -3 && TestBit(kBitIsChain) && !fTree->GetTree()) {
559 fDirector->Notify();
560 if (fProxiesSet) {
561 for (auto value: fValues) {
562 value->NotifyNewTree(fTree->GetTree());
563 }
564 }
565 Warning("SetEntryBase()",
566 "There was an issue opening the last file associated to the TChain "
567 "being processed.");
569 return fEntryStatus;
570 }
571
572 if (loadResult == -2) {
573 fDirector->Notify();
574 if (fProxiesSet) {
575 for (auto value: fValues) {
576 value->NotifyNewTree(fTree->GetTree());
577 }
578 }
580 return fEntryStatus;
581 }
582
583 if (loadResult == -1) {
584 // The chain is empty
586 return fEntryStatus;
587 }
588
589 if (loadResult == -4) {
590 // The TChainElement corresponding to the entry is missing or
591 // the TTree is missing from the file.
592 fDirector->Notify();
593 if (fProxiesSet) {
594 for (auto value: fValues) {
595 value->NotifyNewTree(fTree->GetTree());
596 }
597 }
599 return fEntryStatus;
600 }
601
602 Warning("SetEntryBase()",
603 "Unexpected error '%lld' in %s::LoadTree", loadResult,
604 treeToCallLoadOn->IsA()->GetName());
605
607 return fEntryStatus;
608 }
609
610 if (!fProxiesSet) {
611 if (!SetProxies()) {
613 return fEntryStatus;
614 }
615 }
616
617 if ((fEndEntry >= 0 && entry >= fEndEntry) || (fEntry >= fTree->GetEntriesFast())) {
619 return fEntryStatus;
620 }
621 fDirector->SetReadEntry(loadResult);
623 return fEntryStatus;
624}
625
626////////////////////////////////////////////////////////////////////////////////
627/// Set (or update) the which tree to read from. `tree` can be
628/// a TTree or a TChain.
629
630void TTreeReader::SetTree(TTree* tree, TEntryList* entryList /*= nullptr*/)
631{
632 fTree = tree;
633 fEntryList = entryList;
634 fEntry = -1;
635
636 if (fTree) {
639 } else {
641 }
642
643 if (!fDirector) {
644 Initialize();
645 }
646 else {
649 }
650}
651
652////////////////////////////////////////////////////////////////////////////////
653/// Set (or update) the which tree to read from, passing the name of a tree in a
654/// directory.
655///
656/// \param keyname - name of the tree in `dir`
657/// \param dir - the `TDirectory` to load `keyname` from (or gDirectory if `nullptr`)
658/// \param entryList - the `TEntryList` to attach to the `TTreeReader`.
659
660void TTreeReader::SetTree(const char* keyname, TDirectory* dir, TEntryList* entryList /*= nullptr*/)
661{
662 TTree* tree = nullptr;
663 if (!dir)
664 dir = gDirectory;
665 dir->GetObject(keyname, tree);
666 SetTree(tree, entryList);
667}
668
669////////////////////////////////////////////////////////////////////////////////
670/// Add a value reader for this tree.
671
673{
674 if (fProxiesSet) {
675 Error("RegisterValueReader",
676 "Error registering reader for %s: TTreeReaderValue/Array objects must be created before the call to Next() / SetEntry() / SetLocalEntry(), or after TTreeReader::Restart()!",
677 reader->GetBranchName());
678 return false;
679 }
680 fValues.push_back(reader);
681 return true;
682}
683
684////////////////////////////////////////////////////////////////////////////////
685/// Remove a value reader for this tree.
686
688{
689 std::deque<ROOT::Internal::TTreeReaderValueBase*>::iterator iReader
690 = std::find(fValues.begin(), fValues.end(), reader);
691 if (iReader == fValues.end()) {
692 Error("DeregisterValueReader", "Cannot find reader of type %s for branch %s", reader->GetDerivedTypeName(), reader->fBranchName.Data());
693 return;
694 }
695 fValues.erase(iReader);
696}
#define e(i)
Definition RSha256.hxx:103
long long Long64_t
Definition RtypesCore.h:80
#define ClassImp(name)
Definition Rtypes.h:377
#define gDirectory
Definition TDirectory.h:384
#define R__ASSERT(e)
Definition TError.h:118
Option_t Option_t TPoint TPoint const char GetTextMagnitude GetFillStyle GetLineColor GetLineWidth GetMarkerStyle GetTextAlign GetTextColor GetTextSize void value
void SetReadEntry(Long64_t entry)
Move to a new entry to read entry is the 'local' entry number; i.e.
TTree * SetTree(TTree *newtree)
Set the BranchProxy to be looking at a new tree.
Base class of TTreeReaderValue.
Detail::TBranchProxy * GetProxy() const
virtual const char * GetDerivedTypeName() const =0
TString fBranchName
Name of the branch to read data from.
virtual void CreateProxy()
Create the proxy object for our branch.
A chain is a collection of files containing TTree objects.
Definition TChain.h:33
static TClass * Class()
Describe directory structure in memory.
Definition TDirectory.h:45
void GetObject(const char *namecycle, T *&ptr)
Get an object with proper type checking.
Definition TDirectory.h:212
A List of entry numbers in a TTree or TChain.
Definition TEntryList.h:26
virtual TList * GetLists() const
Definition TEntryList.h:76
virtual Long64_t GetEntryAndTree(Long64_t index, Int_t &treenum)
Return the index of "index"-th non-zero entry in the TTree or TChain and the # of the corresponding t...
virtual Long64_t GetEntry(Long64_t index)
Return the number of the entry #index of this TEntryList in the TTree or TChain See also Next().
virtual Long64_t GetN() const
Definition TEntryList.h:78
const char * GetName() const override
Returns name of object.
Definition TNamed.h:47
void PrependLink(Chain &chain)
Set this link as the head of the chain's list of notify subscribers.
Definition TNotifyLink.h:82
void RemoveLink(Chain &chain)
Remove this link from a chain's list of notify subscribers.
Bool_t IsLinked()
R__ALWAYS_INLINE Bool_t TestBit(UInt_t f) const
Definition TObject.h:201
virtual void Warning(const char *method, const char *msgfmt,...) const
Issue warning message.
Definition TObject.cxx:962
void SetBit(UInt_t f, Bool_t set)
Set or unset the user status bits as specified in f.
Definition TObject.cxx:780
virtual Bool_t InheritsFrom(const char *classname) const
Returns kTRUE if object inherits from class "classname".
Definition TObject.cxx:525
virtual void Error(const char *method, const char *msgfmt,...) const
Issue error message.
Definition TObject.cxx:976
const char * Data() const
Definition TString.h:378
A simple, robust and fast interface to read values from ROOT columnar datasets such as TTree,...
Definition TTreeReader.h:44
TTreeReader()
Default constructor. Call SetTree to connect to a TTree.
ELoadTreeStatus fLoadTreeStatus
Indicator on how LoadTree was called 'last' time.
bool IsInvalid() const
Long64_t GetEntries() const
Returns the number of entries of the TEntryList if one is provided, else of the TTree / TChain,...
EEntryStatus fEntryStatus
status of most recent read request
void SetTree(TTree *tree, TEntryList *entryList=nullptr)
Set (or update) the which tree to read from.
~TTreeReader() override
Tell all value readers that the tree reader does not exist anymore.
TNotifyLink< TTreeReader > fNotify
TTree and TChain will notify this object upon LoadTree, leading to a call to TTreeReader::Notify().
bool fProxiesSet
True if the proxies have been set, false otherwise.
bool IsChain() const
@ kEntryNotFound
the tree entry number does not exist
@ kEntryUnknownError
LoadTree return less than -4, likely a 'newer' error code.
@ kEntryDictionaryError
problem reading dictionary info from tree
@ kEntryBeyondEnd
last entry loop has reached its end
@ kEntryChainFileError
problem in opening a chain's file
@ kEntryNoTree
the tree does not exist
@ kEntryValid
data read okay
bool fSetEntryBaseCallingLoadTree
True if during the LoadTree execution triggered by SetEntryBase.
std::deque< ROOT::Internal::TTreeReaderValueBase * > fValues
readers that use our director
bool RegisterValueReader(ROOT::Internal::TTreeReaderValueBase *reader)
Add a value reader for this tree.
TTree * fTree
tree that's read
ROOT::Internal::TBranchProxyDirector * fDirector
proxying director, owned
EEntryStatus SetEntriesRange(Long64_t beginEntry, Long64_t endEntry)
Set the range of entries to be loaded by Next(); end will not be loaded.
std::deque< ROOT::Internal::TFriendProxy * > fFriendProxies
proxying for friend TTrees, owned
EEntryStatus SetEntryBase(Long64_t entry, bool local)
Load an entry into the tree, return the status of the read.
@ kInternalLoadTree
Notify/LoadTree was last called from SetEntryBase.
@ kNoTree
default state, no TTree is connected (formerly 'Zombie' state)
@ kExternalLoadTree
User code called LoadTree directly.
@ kLoadTreeNone
Notify has not been called yet.
void Initialize()
Initialization of the director.
void Restart()
Restart a Next() loop from entry 0 (of TEntryList index 0 of fEntryList is set).
TEntryList * fEntryList
entry list to be used
Long64_t fEntry
Current (non-local) entry of fTree or of fEntryList if set.
bool Notify() override
Notify director and values of a change in tree.
Long64_t fBeginEntry
This allows us to propagate the range to the TTreeCache.
void DeregisterValueReader(ROOT::Internal::TTreeReaderValueBase *reader)
Remove a value reader for this tree.
@ kBitHaveWarnedAboutEntryListAttachedToTTree
the tree had a TEntryList and we have warned about that
@ kBitIsChain
our tree is a chain
bool SetProxies()
Tell readers we now have a tree.
NamedProxies_t fProxies
attached ROOT::TNamedBranchProxies; owned
Long64_t fEndEntry
The end of the entry loop.
EEntryStatus SetEntry(Long64_t entry)
Set the next entry (or index of the TEntryList if that is set).
static constexpr const char *const fgEntryStatusText[kEntryUnknownError+1]
Long64_t GetCurrentEntry() const
Returns the index of the current entry being read.
A TTree represents a columnar dataset.
Definition TTree.h:79
virtual Int_t StopCacheLearningPhase()
Stop the cache learning phase.
Definition TTree.cxx:9461
virtual Int_t AddBranchToCache(const char *bname, bool subbranches=false)
Add branch with name bname to the Tree cache.
Definition TTree.cxx:1059
TFile * GetCurrentFile() const
Return pointer to the current file.
Definition TTree.cxx:5476
TTreeCache * GetReadCache(TFile *file) const
Find and return the TTreeCache registered with the file and which may contain branches for us.
Definition TTree.cxx:6315
virtual TEntryList * GetEntryList()
Returns the entry list assigned to this tree.
Definition TTree.cxx:5851
virtual Long64_t GetEntries() const
Definition TTree.h:463
virtual TTree * GetTree() const
Definition TTree.h:517
virtual Long64_t LoadTree(Long64_t entry)
Set current entry.
Definition TTree.cxx:6470
virtual Long64_t GetEntriesFast() const
Definition TTree.h:465
TClass * IsA() const override
Definition TTree.h:659
virtual Int_t SetCacheEntryRange(Long64_t first, Long64_t last)
interface to TTreeCache to set the cache entry range
Definition TTree.cxx:8818
static constexpr Long64_t kMaxEntries
Definition TTree.h:229