From 18460a5aa0f46fbd2416d90fb04808c2a191c5f0 Mon Sep 17 00:00:00 2001
From: Julian Viereck <jviereck@tuebingen.mpg.de>
Date: Wed, 23 Sep 2020 14:28:39 +0200
Subject: [PATCH] Tracer: Adding lock to make it threadsafe
---
include/dynamic-graph/tracer.h | 2 ++
src/traces/tracer-real-time.cpp | 1 +
src/traces/tracer.cpp | 9 +++++++++
3 files changed, 12 insertions(+)
diff --git a/include/dynamic-graph/tracer.h b/include/dynamic-graph/tracer.h
index 9861b04..f5c23f2 100644
--- a/include/dynamic-graph/tracer.h
+++ b/include/dynamic-graph/tracer.h
@@ -8,6 +8,7 @@
#include <boost/function.hpp>
#include <list>
#include <string>
+#include <mutex>
#include <dynamic-graph/entity.h>
#include <dynamic-graph/exception-traces.h>
@@ -27,6 +28,7 @@ class DG_TRACER_DLLAPI Tracer : public Entity {
protected:
typedef std::list<const SignalBase<int> *> SignalList;
SignalList toTraceSignals;
+ std::mutex files_mtx;
public:
enum TraceStyle {
diff --git a/src/traces/tracer-real-time.cpp b/src/traces/tracer-real-time.cpp
index ce7985d..70c4c12 100644
--- a/src/traces/tracer-real-time.cpp
+++ b/src/traces/tracer-real-time.cpp
@@ -146,6 +146,7 @@ void TracerRealTime::openFile(const SignalBase<int> &sig,
void TracerRealTime::closeFiles() {
dgDEBUGIN(15);
+ std::lock_guard<std::mutex> files_lock(files_mtx);
FileList::iterator iter = files.begin();
HardFileList::iterator hardIter = hardFiles.begin();
diff --git a/src/traces/tracer.cpp b/src/traces/tracer.cpp
index 99dadd7..e43df73 100644
--- a/src/traces/tracer.cpp
+++ b/src/traces/tracer.cpp
@@ -171,6 +171,7 @@ void Tracer::openFile(const SignalBase<int> &sig, const string &givenname) {
void Tracer::closeFiles() {
dgDEBUGIN(15);
+ std::lock_guard<std::mutex> files_lock(files_mtx);
for (FileList::iterator iter = files.begin(); files.end() != iter; ++iter) {
std::ostream *filePtr = *iter;
@@ -193,6 +194,14 @@ void Tracer::record() {
dgDEBUGIN(15);
+ // Ensure record() never hangs. If the attempt to acquire the lock fails,
+ // then closeFiles() is active and we shouldn't write to files anyways.
+ std::unique_lock<std::mutex> files_lock(files_mtx, std::try_to_lock);
+ if (!files_lock.owns_lock()) {
+ dgDEBUGOUT(15);
+ return;
+ }
+
if (files.size() != toTraceSignals.size()) {
DG_THROW
ExceptionTraces(ExceptionTraces::NOT_OPEN, "No files open for tracing",
--
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