From 55ef0f34612c9fc78f1a1868597976a04228cce7 Mon Sep 17 00:00:00 2001
From: Philippe Canal <pcanal@fnal.gov>
Date: Mon, 1 Mar 2021 14:04:30 -0600
Subject: [PATCH] [NFC] Improve documentation (TTreeCloner, TBufferMerger,
TFileMerger)
---
io/io/inc/ROOT/TBufferMerger.hxx | 2 +-
io/io/src/TBufferMerger.cxx | 3 +++
io/io/src/TFileMerger.cxx | 9 +++++++++
tree/tree/src/TTreeCloner.cxx | 2 +-
4 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/io/io/inc/ROOT/TBufferMerger.hxx b/io/io/inc/ROOT/TBufferMerger.hxx
index bbd3068656a..dc0672d4e27 100644
--- a/io/io/inc/ROOT/TBufferMerger.hxx
+++ b/io/io/inc/ROOT/TBufferMerger.hxx
@@ -99,7 +99,7 @@ public:
*/
void SetMergeOptions(const TString& options);
- /** Indicates that the file will not contain any TTree objects
+ /** Indicates that any TTree objects in the file should be skipped
* and thus that steps that are specific to TTree can be skipped */
void SetNotrees(Bool_t notrees=kFALSE)
{
diff --git a/io/io/src/TBufferMerger.cxx b/io/io/src/TBufferMerger.cxx
index 7575e45f85d..74882f67669 100644
--- a/io/io/src/TBufferMerger.cxx
+++ b/io/io/src/TBufferMerger.cxx
@@ -50,6 +50,9 @@ TBufferMerger::~TBufferMerger()
if (!fQueue.empty())
Merge();
+ // Since we support purely incremental merging, Merge does not write the target objects
+ // that are attached to the file (TTree and histograms) and thus we need to write them
+ // now.
if (TFile *out = fMerger.GetOutputFile())
out->Write("",TObject::kOverwrite);
}
diff --git a/io/io/src/TFileMerger.cxx b/io/io/src/TFileMerger.cxx
index a7e5be06aae..d95ba8172a9 100644
--- a/io/io/src/TFileMerger.cxx
+++ b/io/io/src/TFileMerger.cxx
@@ -930,9 +930,18 @@ Bool_t TFileMerger::PartialMerge(Int_t in_type)
} else {
// Close or write is required so the file is complete.
if (in_type & kIncremental) {
+ // In the case of 'kDelayWrite' the caller want to avoid having to
+ // write the output objects once for every input file and instead
+ // write it only once at the end of the process.
if (!(in_type & kDelayWrite))
fOutputFile->Write("",TObject::kOverwrite);
} else {
+ // If in_type is not incremental but type is incremental we are now in
+ // the case where the user "explicitly" request a non-incremental merge
+ // but we still have internally an incremental merge. Because the user
+ // did not request the incremental merge they also probably do not to a
+ // final Write of the file and thus not doing the write here would lead
+ // to data loss ...
if (type & kIncremental)
fOutputFile->Write("",TObject::kOverwrite);
gROOT->GetListOfFiles()->Remove(fOutputFile);
diff --git a/tree/tree/src/TTreeCloner.cxx b/tree/tree/src/TTreeCloner.cxx
index a98260612af..974c040fd83 100644
--- a/tree/tree/src/TTreeCloner.cxx
+++ b/tree/tree/src/TTreeCloner.cxx
@@ -110,7 +110,7 @@ TTreeCloner::TTreeCloner(TTree *from, TTree *to, Option_t *method, UInt_t option
////////////////////////////////////////////////////////////////////////////////
/// Constructor. In place cloning.
//// This object would transfer the data from
-/// 'from' the original location to 'to' the new directory
+/// 'from' the original location to 'newdirectory' the new directory
/// using the sorting method indicated in method.
/// It updates the 'from' TTree with the new information.
/// See TTreeCloner::TTreeCloner(TTree *from, TTree *to, Option_t *method, UInt_t options)
--
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