From 082a5f63f8b0a5d0fc942cbab4b4f39b40459b3f Mon Sep 17 00:00:00 2001
From: Sergey Linev <S.Linev@gsi.de>
Date: Thu, 6 Sep 2018 17:08:18 +0200
Subject: [PATCH] webgui: use special mutex in canvas painter to protect I/O
When many threads tries to stream same class for first time - it causes
I/O problem while many TClass and TStreamerInfo instances need to be
created. Probably global ROOT mutex has to be used.
---
gui/canvaspainter/v7/src/TCanvasPainter.cxx | 23 ++++++++++++++++-----
1 file changed, 18 insertions(+), 5 deletions(-)
diff --git a/gui/canvaspainter/v7/src/TCanvasPainter.cxx b/gui/canvaspainter/v7/src/TCanvasPainter.cxx
index 69150ace1a7..ad4b861ac3b 100644
--- a/gui/canvaspainter/v7/src/TCanvasPainter.cxx
+++ b/gui/canvaspainter/v7/src/TCanvasPainter.cxx
@@ -23,6 +23,8 @@
#include <ROOT/TWebWindow.hxx>
#include <ROOT/TWebWindowsManager.hxx>
+// #include "TVirtualMutex.h"
+
#include <memory>
#include <string>
#include <vector>
@@ -30,6 +32,7 @@
#include <thread>
#include <chrono>
#include <fstream>
+#include <mutex>
#include "TList.h"
#include "TROOT.h"
@@ -612,12 +615,22 @@ std::string ROOT::Experimental::TCanvasPainter::CreateSnapshot(const ROOT::Exper
fPadDisplayItem->SetTitle(can.GetTitle());
fPadDisplayItem->SetWindowSize(can.GetSize());
- TString res = TBufferJSON::ToJSON(fPadDisplayItem.get(), 23);
+ static std::mutex sIOMutex;
+
+ TString res;
+
+ {
+ std::lock_guard<std::mutex> grd(sIOMutex);
- if (!fNextDumpName.empty()) {
- TBufferJSON::ExportToFile(fNextDumpName.c_str(), fPadDisplayItem.get(),
- gROOT->GetClass("ROOT::Experimental::RPadDisplayItem"));
- fNextDumpName.clear();
+ // R__LOCKGUARD(gROOTMutex);
+
+ res = TBufferJSON::ToJSON(fPadDisplayItem.get(), 23);
+
+ if (!fNextDumpName.empty()) {
+ TBufferJSON::ExportToFile(fNextDumpName.c_str(), fPadDisplayItem.get(),
+ gROOT->GetClass("ROOT::Experimental::RPadDisplayItem"));
+ fNextDumpName.clear();
+ }
}
fPadDisplayItem.reset(); // no need to keep memory any longer
--
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