From a1cbbc7a9175d662d9830157938dbb33f15dc7ec Mon Sep 17 00:00:00 2001
From: Fabio Cossutti <fabio.cossutti@ts.infn.it>
Date: Thu, 12 Apr 2018 17:39:48 +0200
Subject: [PATCH] Backport of #22935 to 93X

---
 .../plugins/ExternalLHEAsciiDumper.cc         | 10 ++++---
 .../plugins/ExternalLHEProducer.cc            | 27 ++++++++++++-------
 .../python/ExternalLHEProducer_cfi.py         |  3 ++-
 3 files changed, 26 insertions(+), 14 deletions(-)

diff --git a/GeneratorInterface/LHEInterface/plugins/ExternalLHEAsciiDumper.cc b/GeneratorInterface/LHEInterface/plugins/ExternalLHEAsciiDumper.cc
index 4aa56cddf382c..be486d25eeff5 100644
--- a/GeneratorInterface/LHEInterface/plugins/ExternalLHEAsciiDumper.cc
+++ b/GeneratorInterface/LHEInterface/plugins/ExternalLHEAsciiDumper.cc
@@ -42,6 +42,8 @@ class ExternalLHEAsciiDumper : public edm::EDAnalyzer {
   edm::InputTag lheProduct_;
   std::string   lheFileName_;
 
+  edm::EDGetTokenT<LHEXMLStringProduct> LHEAsciiToken_;
+
   // ----------member data ---------------------------
   
 };
@@ -50,6 +52,8 @@ ExternalLHEAsciiDumper::ExternalLHEAsciiDumper(const edm::ParameterSet& ps):
   lheProduct_( ps.getParameter<edm::InputTag>("lheProduct") ),
   lheFileName_( ps.getParameter<std::string>("lheFileName") )
 {
+
+  LHEAsciiToken_ = consumes <LHEXMLStringProduct,edm::InRun> (edm::InputTag(lheProduct_));
   
   return;
   
@@ -70,7 +74,7 @@ void
 ExternalLHEAsciiDumper::endRun(edm::Run const& iRun, edm::EventSetup const&) {
 
   edm::Handle< LHEXMLStringProduct > LHEAscii;
-  iRun.getByLabel(lheProduct_,LHEAscii);
+  iRun.getByToken(LHEAsciiToken_,LHEAscii);
   
   const std::vector<std::string>& lheOutputs = LHEAscii->getStrings();
 
@@ -87,7 +91,7 @@ ExternalLHEAsciiDumper::endRun(edm::Run const& iRun, edm::EventSetup const&) {
     else {
       std::stringstream fname;
       fname << basename << "_" << iout ;
-      if (extension != "")
+      if (!extension.empty())
         fname << "." << extension;
       outfile.open (fname.str().c_str(), std::ofstream::out | std::ofstream::app);
     }
@@ -103,7 +107,7 @@ ExternalLHEAsciiDumper::endRun(edm::Run const& iRun, edm::EventSetup const&) {
     else {
       std::stringstream fname;
       fname << basename << "_" << iout ;
-      if (extension != "")
+      if (!extension.empty())
         fname << "." << extension;
       outfile.open (fname.str().c_str(), std::ofstream::out | std::ofstream::app);
     }
diff --git a/GeneratorInterface/LHEInterface/plugins/ExternalLHEProducer.cc b/GeneratorInterface/LHEInterface/plugins/ExternalLHEProducer.cc
index 2f18416c533bf..98dd211e1f7e5 100644
--- a/GeneratorInterface/LHEInterface/plugins/ExternalLHEProducer.cc
+++ b/GeneratorInterface/LHEInterface/plugins/ExternalLHEProducer.cc
@@ -93,6 +93,7 @@ class ExternalLHEProducer : public edm::one::EDProducer<edm::BeginRunProducer,
   std::vector<std::string> args_;
   uint32_t npars_;
   uint32_t nEvents_;
+  bool storeXML_;
   unsigned int nThreads_{1};
   std::string outputContents_;
 
@@ -133,7 +134,8 @@ ExternalLHEProducer::ExternalLHEProducer(const edm::ParameterSet& iConfig) :
   outputFile_(iConfig.getParameter<std::string>("outputFile")),
   args_(iConfig.getParameter<std::vector<std::string> >("args")),
   npars_(iConfig.getParameter<uint32_t>("numberOfParameters")),
-  nEvents_(iConfig.getUntrackedParameter<uint32_t>("nEvents"))
+  nEvents_(iConfig.getUntrackedParameter<uint32_t>("nEvents")),
+  storeXML_(iConfig.getUntrackedParameter<bool>("storeXML"))
 {
   if (npars_ != args_.size())
     throw cms::Exception("ExternalLHEProducer") << "Problem with configuration: " << args_.size() << " script arguments given, expected " << npars_;
@@ -256,17 +258,21 @@ ExternalLHEProducer::beginRunProduce(edm::Run& run, edm::EventSetup const& es)
 
   executeScript();
   
+
   //fill LHEXMLProduct (streaming read directly into compressed buffer to save memory)
   std::unique_ptr<LHEXMLStringProduct> p(new LHEXMLStringProduct);
-  std::ifstream instream(outputFile_);
-  if (!instream) {
-    throw cms::Exception("OutputOpenError") << "Unable to open script output file " << outputFile_ << ".";
-  }  
-  instream.seekg (0, instream.end);
-  int insize = instream.tellg();
-  instream.seekg (0, instream.beg);  
-  p->fillCompressedContent(instream, 0.25*insize);
-  instream.close();
+
+  //store the XML file only if explictly requested
+  if (storeXML_) {  std::ifstream instream(outputFile_);
+    if (!instream) {
+      throw cms::Exception("OutputOpenError") << "Unable to open script output file " << outputFile_ << ".";
+    }  
+    instream.seekg (0, instream.end);
+    int insize = instream.tellg();
+    instream.seekg (0, instream.beg);  
+    p->fillCompressedContent(instream, 0.25*insize);
+    instream.close();
+  }
   run.put(std::move(p), "LHEScriptOutput");
 
   // LHE C++ classes translation
@@ -499,6 +505,7 @@ ExternalLHEProducer::fillDescriptions(edm::ConfigurationDescriptions& descriptio
   desc.add<std::vector<std::string> >("args");
   desc.add<uint32_t>("numberOfParameters");
   desc.addUntracked<uint32_t>("nEvents");
+  desc.addUntracked<bool>("storeXML", false);
 
   descriptions.addDefault(desc);
 }
diff --git a/GeneratorInterface/LHEInterface/python/ExternalLHEProducer_cfi.py b/GeneratorInterface/LHEInterface/python/ExternalLHEProducer_cfi.py
index 59e4a9259898b..cbc8824b306f2 100644
--- a/GeneratorInterface/LHEInterface/python/ExternalLHEProducer_cfi.py
+++ b/GeneratorInterface/LHEInterface/python/ExternalLHEProducer_cfi.py
@@ -5,6 +5,7 @@
     outputFile = cms.string("W1Jet_7TeV_madgraph_final.lhe"),
     numberOfParameters = cms.uint32(10),
     args = cms.vstring('slc5_ia32_gcc434/madgraph/V5_1.3.27/test','W1Jet_7TeV_madgraph','false','true','wjets','5','20','false','0','99'),
-    nEvents = cms.untracked.uint32(100)                                    
+    nEvents = cms.untracked.uint32(100),
+    storeXML = cms.untracked.bool(False)                                    
 )