Restore broken low memory watcher functionality in JPS process;

JPS: on LowMemory signal clear also FSCache

jps/jps-builders/src/org/jetbrains/jps/cmdline/BuildSession.java

@@ -16,6 +16,8 @@
 package org.jetbrains.jps.cmdline;
 
 import com.intellij.openapi.diagnostic.Logger;
+import com.intellij.openapi.util.Disposer;
+import com.intellij.openapi.util.LowMemoryWatcherManager;
 import com.intellij.openapi.util.Pair;
 import com.intellij.openapi.util.Ref;
 import com.intellij.openapi.util.io.BufferExposingByteArrayOutputStream;
@@ -121,6 +123,7 @@ final class BuildSession implements Runnable, CanceledStatus {
 
   @Override
   public void run() {
+    final LowMemoryWatcherManager memWatcher = new LowMemoryWatcherManager(SharedThreadPool.getInstance());
     Throwable error = null;
     final Ref<Boolean> hasErrors = new Ref<>(false);
     final Ref<Boolean> doneSomething = new Ref<>(false);
@@ -198,6 +201,7 @@ final class BuildSession implements Runnable, CanceledStatus {
     }
     finally {
       finishBuild(error, hasErrors.get(), doneSomething.get());
+      Disposer.dispose(memWatcher);
     }
   }
 

jps/jps-builders/src/org/jetbrains/jps/incremental/IncProjectBuilder.java

@@ -170,6 +170,7 @@ public class IncProjectBuilder {
   public void build(CompileScope scope, boolean forceCleanCaches) throws RebuildRequestedException {
 
     final LowMemoryWatcher memWatcher = LowMemoryWatcher.register(() -> {
+      myProjectDescriptor.getFSCache().clear();
       JavacMain.clearCompilerZipFileCache();
       myProjectDescriptor.dataManager.flush(false);
       myProjectDescriptor.timestamps.getStorage().force();

jps/standalone-builder/src/org/jetbrains/jps/build/Standalone.java

@@ -15,6 +15,8 @@
  */
 package org.jetbrains.jps.build;
 
+import com.intellij.openapi.util.Disposer;
+import com.intellij.openapi.util.LowMemoryWatcherManager;
 import com.intellij.openapi.util.io.FileUtil;
 import com.intellij.util.ArrayUtil;
 import com.intellij.util.ParameterizedRunnable;
@@ -31,6 +33,7 @@ import org.jetbrains.jps.incremental.fs.BuildFSState;
 import org.jetbrains.jps.incremental.messages.BuildMessage;
 import org.jetbrains.jps.incremental.messages.CompilerMessage;
 import org.jetbrains.jps.model.JpsModel;
+import org.jetbrains.jps.service.SharedThreadPool;
 
 import java.io.File;
 import java.util.*;
@@ -200,6 +203,7 @@ public class Standalone {
 
   public static void runBuild(JpsModelLoader loader, File dataStorageRoot, MessageHandler messageHandler, List<TargetTypeBuildScope> scopes,
                               boolean includeDependenciesToScope) throws Exception {
+    final LowMemoryWatcherManager memWatcher = new LowMemoryWatcherManager(SharedThreadPool.getInstance());
     final BuildRunner buildRunner = new BuildRunner(loader);
     ProjectDescriptor descriptor = buildRunner.load(messageHandler, dataStorageRoot, new BuildFSState(true));
     try {
@@ -207,6 +211,7 @@ public class Standalone {
     }
     finally {
       descriptor.release();
+      Disposer.dispose(memWatcher);
     }
   }
 

platform/util/src/com/intellij/openapi/util/LowMemoryWatcherManager.java

@@ -31,6 +31,7 @@ import java.lang.management.MemoryNotificationInfo;
 import java.lang.management.MemoryPoolMXBean;
 import java.lang.management.MemoryType;
 import java.util.MissingResourceException;
+import java.util.concurrent.Executor;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Future;
 import java.util.concurrent.atomic.AtomicBoolean;
@@ -55,7 +56,7 @@ public class LowMemoryWatcherManager implements Disposable {
     }
   };
 
-  public LowMemoryWatcherManager(@NotNull ExecutorService executorService) {
+  public LowMemoryWatcherManager(@NotNull Executor executorService) {
     myExecutorService = SequentialTaskExecutor.createSequentialApplicationPoolExecutor("LowMemoryWatcherManager", executorService);
     try {
       for (MemoryPoolMXBean bean : ManagementFactory.getMemoryPoolMXBeans()) {