From c3d949ddba1e9c5ade93a629a722a782c60e94a0 Mon Sep 17 00:00:00 2001
From: vsonnier <vsonnier@users.noreply.github.com>
Date: Wed, 1 Jun 2016 19:51:01 +0200
Subject: [PATCH] MISC 3: Make the whole BufferType life-cycle and recycling
 properly guarded against concurrent access

---
 src/IOThread.h | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/src/IOThread.h b/src/IOThread.h
index eb4e94d..9d9232b 100644
--- a/src/IOThread.h
+++ b/src/IOThread.h
@@ -20,6 +20,7 @@ struct map_string_less : public std::binary_function<std::string,std::string,boo
 
 
 class ReferenceCounter {
+
 public:
     
     void setRefCount(int rc) {
@@ -56,17 +57,19 @@ public:
     }
     
     BufferType *getBuffer() {
-        BufferType* buf = NULL;
+        std::lock_guard < std::mutex > lock(m_mutex);
+
+        BufferType* buf = nullptr;
         for (outputBuffersI = outputBuffers.begin(); outputBuffersI != outputBuffers.end(); outputBuffersI++) {
-            if (!buf && (*outputBuffersI)->getRefCount() <= 0) {
+            if (buf == nullptr && (*outputBuffersI)->getRefCount() <= 0) {
                 buf = (*outputBuffersI);
-                (*outputBuffersI)->setRefCount(0);
+                buf->setRefCount(0);
             } else if ((*outputBuffersI)->getRefCount() <= 0) {
                 (*outputBuffersI)->decRefCount();
             }
         }
         
-        if (buf) {
+        if (buf != nullptr) {
             if (outputBuffers.back()->getRefCount() < -REBUFFER_GC_LIMIT) {
                 BufferType *ref = outputBuffers.back();
                 outputBuffers.pop_back();
@@ -87,6 +90,7 @@ public:
     }
     
     void purge() {
+        std::lock_guard < std::mutex > lock(m_mutex);
         while (!outputBuffers.empty()) {
             BufferType *ref = outputBuffers.front();
             outputBuffers.pop_front();
@@ -97,6 +101,7 @@ private:
     std::string bufferId;
     std::deque<BufferType*> outputBuffers;
     typename std::deque<BufferType*>::iterator outputBuffersI;
+    mutable std::mutex m_mutex;
 };