Make the task manager cancel operation thread-safe

qgis · Mar 20, 2020 · 046b1e8 · 046b1e8
1 parent 722a41e
commit 046b1e8
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Showing 3 changed files with 10 additions and 4 deletions.
diff --git a/src/core/qgstaskmanager.cpp b/src/core/qgstaskmanager.cpp
@@ -91,7 +91,9 @@ void QgsTask::cancel()
   if ( mOverallStatus == Complete || mOverallStatus == Terminated )
     return;
 
+  mShouldTerminateMutex.lock();
   mShouldTerminate = true;
+  mShouldTerminateMutex.unlock();
   if ( mStatus == Queued || mStatus == OnHold )
   {
     // immediately terminate unstarted jobs
@@ -111,6 +113,12 @@ void QgsTask::cancel()
   }
 }
 
+bool QgsTask::isCanceled() const
+{
+  QMutexLocker locker( &mShouldTerminateMutex );
+  return mShouldTerminate;
+}
+
 void QgsTask::hold()
 {
   if ( mStatus == Queued )

diff --git a/src/core/qgstaskmanager.h b/src/core/qgstaskmanager.h
@@ -283,7 +283,7 @@ class CORE_EXPORT QgsTask : public QObject
      * flag, then derived classes' run() methods should periodically check this and
      * terminate in a safe manner.
      */
-    bool isCanceled() const { return mShouldTerminate; }
+    bool isCanceled() const;
 
   protected slots:
 
@@ -323,6 +323,7 @@ class CORE_EXPORT QgsTask : public QObject
     //! Overall progress of this task and all subtasks
     double mTotalProgress = 0.0;
     bool mShouldTerminate = false;
+    mutable QMutex mShouldTerminateMutex;
     int mStartCount = 0;
 
     struct SubTask

diff --git a/tests/src/core/testqgstaskmanager.cpp b/tests/src/core/testqgstaskmanager.cpp
@@ -133,9 +133,6 @@ class CancelableTask : public QgsTask
     ~CancelableTask() override
     {
       qDebug() << "deleting task " << description();
-
-      int i = 1;
-      i++;
     }
 
   protected: