VSC: better suspend logic for continuation, to avoid potential duplicate tasks after suspend-awake (separate progress runner)

platform/vcs-impl/src/com/intellij/util/continuation/GeneralRunner.java

@@ -28,6 +28,7 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 import java.util.*;
+import java.util.concurrent.atomic.AtomicInteger;
 
 /**
 * @author irengrig
@@ -39,7 +40,7 @@ abstract class GeneralRunner implements ContinuationContext {
   protected final boolean myCancellable;
   protected final List<TaskDescriptor> myQueue;
   protected final Object myQueueLock;
-  protected volatile boolean myTriggerSuspend;
+  private boolean myTriggerSuspend;
   protected ProgressIndicator myIndicator;
   protected final Map<Object, Object> myDisasters;
   private final List<Consumer<TaskDescriptor>> myTasksPatchers;
@@ -53,6 +54,7 @@ abstract class GeneralRunner implements ContinuationContext {
     myDisasters = new HashMap<Object, Object>();
     myHandlersMap = new HashMap<Class<? extends Exception>, Consumer<Exception>>();
     myTasksPatchers = new ArrayList<Consumer<TaskDescriptor>>();
+    myTriggerSuspend = false;
   }
 
   public <T extends Exception> void addExceptionHandler(final Class<T> clazz, final Consumer<T> consumer) {
@@ -113,7 +115,21 @@ abstract class GeneralRunner implements ContinuationContext {
   }
 
   public void suspend() {
-    myTriggerSuspend = true;
+    synchronized (myQueueLock) {
+      myTriggerSuspend = true;
+    }
+  }
+
+  protected boolean getSuspendFlag() {
+    synchronized (myQueueLock) {
+      return myTriggerSuspend;
+    }
+  }
+
+  protected void clearSuspend() {
+    synchronized (myQueueLock) {
+      myTriggerSuspend = false;
+    }
   }
 
   @Override
@@ -241,13 +257,10 @@ abstract class GeneralRunner implements ContinuationContext {
     ping();
   }
 
-  // null - no more tasks or suspend
+  // null - no more tasks
   @Nullable
   protected TaskDescriptor getNextMatching() {
     while (true) {
-      if (myTriggerSuspend) {
-        return null;
-      }
       synchronized (myQueueLock) {
         if (myQueue.isEmpty()) return null;
         TaskDescriptor current = myQueue.remove(0);

platform/vcs-impl/src/com/intellij/util/continuation/SameProgressRunner.java

@@ -52,7 +52,7 @@ public class SameProgressRunner extends GeneralRunner {
 
   @Override
   public void ping() {
-    myTriggerSuspend = false;
+    clearSuspend();
     if (Thread.currentThread().equals(myInitThread)) {
       pingInSourceThread();
     } else {
@@ -66,17 +66,16 @@ public class SameProgressRunner extends GeneralRunner {
         // stop if project is being disposed
         if (! myProject.isOpen()) return;
 
+        if (getSuspendFlag()) {
+          mySemaphore.down();
+          while (getSuspendFlag()) {
+            mySemaphore.waitFor(500);
+          }
+        }
+
         final TaskDescriptor current = getNextMatching();
         if (current == null) {
-          if (myTriggerSuspend) {
-            mySemaphore.down();
-            while (myTriggerSuspend) {
-              mySemaphore.waitFor(500);
-            }
-            continue;
-          } else {
-            return;
-          }
+          return;
         }
 
         if (Where.AWT.equals(current.getWhere())) {

platform/vcs-impl/src/com/intellij/util/continuation/SeparatePiecesRunner.java

@@ -40,6 +40,7 @@ public class SeparatePiecesRunner extends GeneralRunner {
 
   @CalledInAwt
   public void ping() {
+    clearSuspend();
     if (! ApplicationManager.getApplication().isDispatchThread()) {
       Runnable command = new Runnable() {
         public void run() {
@@ -52,15 +53,14 @@ public class SeparatePiecesRunner extends GeneralRunner {
     }
   }
 
+  @CalledInAwt
   private void pingImpl() {
     while (true) {
     // stop if project is being disposed
       if (! myProject.isDefault() && ! myProject.isOpen()) return;
+      if (getSuspendFlag()) return;
       final TaskDescriptor current = getNextMatching();
       if (current == null) {
-        synchronized (myQueueLock) {
-          myTriggerSuspend = false;
-        }
         return;
       }