From bb551432e3ffd39cae5cb4e342eabd79ee38296f Mon Sep 17 00:00:00 2001
From: Erik Broberg <Erik Broberg>
Date: Fri, 20 May 2016 12:55:37 -0400
Subject: [PATCH] ConcurrentJobManager uses ThreadPool to do parallel Gdal
 RasterIO calls. Some tile gets corrupted...

---
 .../other/concurrentjobmanager.h              | 39 +++----------------
 modules/globebrowsing/other/threadpool.cpp    |  9 ++++-
 modules/globebrowsing/other/threadpool.h      |  1 +
 modules/globebrowsing/other/tileprovider.cpp  |  1 +
 modules/globebrowsing/other/tileprovider.h    |  2 +-
 5 files changed, 16 insertions(+), 36 deletions(-)

diff --git a/modules/globebrowsing/other/concurrentjobmanager.h b/modules/globebrowsing/other/concurrentjobmanager.h
index 33cd150b5a..04df7c5f90 100644
--- a/modules/globebrowsing/other/concurrentjobmanager.h
+++ b/modules/globebrowsing/other/concurrentjobmanager.h
@@ -65,7 +65,6 @@ namespace openspace {
     class ConcurrentJobManager{
     public:
         ConcurrentJobManager()
-        : _hasWorkingThread(false)
         {
 
         }
@@ -76,17 +75,14 @@ namespace openspace {
 
 
         void enqueueJob(std::shared_ptr<Job<P>> job) {
-            _incomingJobs.push(job);
-            if (!_hasWorkingThread) {
-                _hasWorkingThread = true; // Can only be set to true by the main thread
-                executeJobsInSeparateThread();
-            }
+            TileProvider::threadPool.enqueue([this, job]() {
+                job->execute();
+                _finishedJobs.push(job);
+            });
         }
 
         void clearEnqueuedJobs() {
-            while (_incomingJobs.size()) {
-                _incomingJobs.pop();
-            }
+            TileProvider::threadPool.clearTasks();
         }
 
         std::shared_ptr<Job<P>> popFinishedJob() {
@@ -102,33 +98,8 @@ namespace openspace {
     
     private:
 
-
-        void executeJobsInSeparateThread() {
-            // Create new thread and run workerThreadMainTask on that thread
-            std::thread t(&ConcurrentJobManager::workerThreadMainTask, this);
-            t.detach();
-        }
-        
-        void workerThreadMainTask() {
-            while (_incomingJobs.size() > 0) {
-                auto job = _incomingJobs.pop();                
-
-                job->execute();
-
-                _finishedJobs.push(job);
-            }
-
-            _hasWorkingThread = false; // Can only be set to false by worker thread
-        }
-
-        ConcurrentQueue<std::shared_ptr<Job<P>>> _incomingJobs;
         ConcurrentQueue<std::shared_ptr<Job<P>>> _finishedJobs;
 
-        // Using this atomic bool is probably not optimal - Should probably
-        // use a conditional variable instead
-        std::atomic<bool> _hasWorkingThread;
-        std::atomic<int> _numActiveThreads;
-
     };
 
 
diff --git a/modules/globebrowsing/other/threadpool.cpp b/modules/globebrowsing/other/threadpool.cpp
index 8712ed65b6..daf3c80559 100644
--- a/modules/globebrowsing/other/threadpool.cpp
+++ b/modules/globebrowsing/other/threadpool.cpp
@@ -113,8 +113,15 @@ namespace openspace {
         } // release lock
 
           // wake up one thread
-        std::cout << "Notify one thread" << std::endl;
         condition.notify_one();
     }
 
+    void ThreadPool::clearTasks() {
+        { // acquire lock
+            std::unique_lock<std::mutex> lock(queue_mutex);
+            tasks.clear();
+        } // release lock
+    }
+
+
 } // namespace openspace
\ No newline at end of file
diff --git a/modules/globebrowsing/other/threadpool.h b/modules/globebrowsing/other/threadpool.h
index 73ae6a2d6d..d792ee01d0 100644
--- a/modules/globebrowsing/other/threadpool.h
+++ b/modules/globebrowsing/other/threadpool.h
@@ -59,6 +59,7 @@ namespace openspace {
         ~ThreadPool();
 
         void enqueue(std::function<void()> f);
+        void clearTasks();
 
     private:
         friend class Worker;
diff --git a/modules/globebrowsing/other/tileprovider.cpp b/modules/globebrowsing/other/tileprovider.cpp
index 6ff9d420fa..36c7c85378 100644
--- a/modules/globebrowsing/other/tileprovider.cpp
+++ b/modules/globebrowsing/other/tileprovider.cpp
@@ -45,6 +45,7 @@ namespace openspace {
 
     bool TileProvider::hasInitializedGDAL = false;
 
+    ThreadPool TileProvider::threadPool(10);
 
 
     TileProvider::TileProvider(
diff --git a/modules/globebrowsing/other/tileprovider.h b/modules/globebrowsing/other/tileprovider.h
index 02b70c585b..28b43f44f9 100644
--- a/modules/globebrowsing/other/tileprovider.h
+++ b/modules/globebrowsing/other/tileprovider.h
@@ -82,7 +82,7 @@ namespace openspace {
 
         void prerender();
 
-        
+        static ThreadPool threadPool;
 
 
     private: