HEAD without the locks in Graph.cpp
It's a typical race condition, see output with attached patch:
184 74127768 size 1 , thread:
186 74127768 size 1 , thread:
36 19714232 size 0 , thread:
This means
line 184: thread 74127768 checks if Q is not empty > enter the while loop
line 186: Q is still not empty, the thread will call front in the next line
line 36: But in he meantime a other thread has cleared Q so it craches
when thread 74127768 calls front()
Peter
Index: Graph.cpp
===================================================================
--- Graph.cpp (revision 37227)
+++ Graph.cpp (working copy)
@@ -19,6 +19,9 @@
#include <algorithm>
+#include <QDebug>
+#include <QThread>
+
using namespace std;
namespace lyx {
@@ -30,6 +33,7 @@
return false;
Q_ = queue<int>();
+ qDebug() << __LINE__ << (int)QThread::currentThread() << "size" << Q_.size() << ", thread: ";
if (clear_visited) {
vector<Vertex>::iterator it = vertices_.begin();
@@ -57,7 +61,7 @@
vector<int> const
Graph::getReachableTo(int target, bool clear_visited)
{
- Mutex::Locker lock(&mutex_);
+ //Mutex::Locker lock(&mutex_);
vector<int> result;
if (!bfs_init(target, clear_visited))
@@ -94,7 +98,7 @@
Graph::getReachable(int from, bool only_viewable,
bool clear_visited)
{
- Mutex::Locker lock(&mutex_);
+ //Mutex::Locker lock(&mutex_);
vector<int> result;
if (!bfs_init(from, clear_visited))
@@ -132,7 +136,7 @@
bool Graph::isReachable(int from, int to)
{
- Mutex::Locker lock(&mutex_);
+ //Mutex::Locker lock(&mutex_);
if (from == to)
return true;
@@ -165,18 +169,25 @@
Graph::EdgePath const Graph::getPath(int from, int to)
{
- Mutex::Locker lock(&mutex_);
+ //Mutex::Locker lock(&mutex_);
+ //qDebug() << __LINE__ << (int)QThread::currentThread() << "Graph:" << (int) this;
+
if (from == to)
return EdgePath();
if (to < 0 || !bfs_init(from))
return EdgePath();
+
clearPaths();
+ qDebug() << __LINE__ << (int)QThread::currentThread() << "size" << Q_.size() << ", thread: ";
while (!Q_.empty()) {
+ qDebug() << __LINE__ << (int)QThread::currentThread() << "size" << Q_.size() << ", thread: ";
int const current = Q_.front();
+ qDebug() << __LINE__ << (int)QThread::currentThread() << "size" << Q_.size() << ", thread: ";
Q_.pop();
+ qDebug() << __LINE__ << (int)QThread::currentThread() << "size" << Q_.size() << ", thread: ";
vector<Arrow *>::const_iterator cit =
vertices_[current].out_arrows.begin();
@@ -206,7 +217,7 @@
void Graph::init(int size)
{
- Mutex::Locker lock(&mutex_);
+ //Mutex::Locker lock(&mutex_);
vertices_ = vector<Vertex>(size);
arrows_.clear();
@@ -216,7 +227,7 @@
void Graph::addEdge(int from, int to)
{
- Mutex::Locker lock(&mutex_);
+ //Mutex::Locker lock(&mutex_);
arrows_.push_back(Arrow(from, to, numedges_));
numedges_++;
