1 files changed, 22 insertions, 2 deletions
diff --git a/comphelper/source/misc/threadpool.cxx b/comphelper/source/misc/threadpool.cxx
index f93400d96f9f..906189202cdd 100644
--- a/comphelper/source/misc/threadpool.cxx
+++ b/comphelper/source/misc/threadpool.cxx
@@ -79,12 +79,14 @@ public:
             std::unique_ptr<ThreadTask> pTask = mpPool->popWorkLocked( aGuard, true );
             if( pTask )
             {
+                mpPool->incBusyWorker();
                 aGuard.unlock();
 
                 pTask->exec();
                 pTask.reset();
 
                 aGuard.lock();
+                mpPool->decBusyWorker();
             }
         }
     }
@@ -92,7 +94,8 @@ public:
 
 ThreadPool::ThreadPool(sal_Int32 nWorkers)
     : mbTerminate(true)
-    , mnWorkers(nWorkers)
+    , mnMaxWorkers(nWorkers)
+    , mnBusyWorkers(0)
 {
 }
 
@@ -104,6 +107,7 @@ ThreadPool::~ThreadPool()
     // still 0, but hopefully they will be more helpful on non-WNT platforms
     assert(mbTerminate);
     assert(maTasks.empty());
+    assert(mnBusyWorkers == 0);
 }
 
 namespace {
@@ -198,7 +202,8 @@ void ThreadPool::pushTask( std::unique_ptr<ThreadTask> pTask )
 
     mbTerminate = false;
 
-    if (maWorkers.size() < mnWorkers && maWorkers.size() <= maTasks.size())
+    // Worked on tasks are already removed from maTasks, so include the count of busy workers.
+    if (maWorkers.size() < mnMaxWorkers && maWorkers.size() <= maTasks.size() + mnBusyWorkers)
     {
         maWorkers.push_back( new ThreadWorker( this ) );
         maWorkers.back()->launch();
@@ -230,6 +235,17 @@ std::unique_ptr<ThreadTask> ThreadPool::popWorkLocked( std::unique_lock< std::mu
     return nullptr;
 }
 
+void ThreadPool::incBusyWorker()
+{
+    ++mnBusyWorkers;
+}
+
+void ThreadPool::decBusyWorker()
+{
+    --mnBusyWorkers;
+    assert(mnBusyWorkers >= 0);
+}
+
 void ThreadPool::waitUntilDone(const std::shared_ptr<ThreadTaskTag>& rTag, bool bJoinAll)
 {
 #if defined DBG_UTIL && (defined LINUX || defined _WIN32)
@@ -294,6 +310,10 @@ void ThreadTask::exec()
     {
         SAL_WARN("comphelper", "exception in thread worker while calling doWork(): " << e);
     }
+    catch (...)
+    {
+        SAL_WARN("comphelper", "unknown exception in thread worker while calling doWork()");
+    }
 
     pTag->onTaskWorkerDone();
 }