From 56d9c82c5b512b3638fb43cdcacf9d1432355f42 Mon Sep 17 00:00:00 2001
From: "Ilya.Kazakevich" <Ilya.Kazakevich@jetbrains.com>
Date: Wed, 1 Jun 2016 00:15:48 +0300
Subject: [PATCH] Strong references removed from ``PythonPathCache`` since
 cache should not prevent anything from GC

---
 .../python/psi/resolve/PythonPathCache.java   | 23 +++++++++++++------
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/python/src/com/jetbrains/python/psi/resolve/PythonPathCache.java b/python/src/com/jetbrains/python/psi/resolve/PythonPathCache.java
index 2ff1e388c903..c95e23707738 100644
--- a/python/src/com/jetbrains/python/psi/resolve/PythonPathCache.java
+++ b/python/src/com/jetbrains/python/psi/resolve/PythonPathCache.java
@@ -19,6 +19,7 @@ import com.intellij.openapi.diagnostic.Logger;
 import com.intellij.openapi.vfs.*;
 import com.intellij.psi.PsiElement;
 import com.intellij.psi.util.QualifiedName;
+import com.intellij.reference.SoftReference;
 import com.intellij.util.containers.ContainerUtil;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -26,13 +27,14 @@ import org.jetbrains.annotations.Nullable;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
+import java.util.stream.Collectors;
 
 /**
  * @author yole
  */
 public abstract class PythonPathCache {
-  private final Map<QualifiedName, List<PsiElement>> myCache = ContainerUtil.newConcurrentMap();
-  private final Map<VirtualFile, List<QualifiedName>> myQNameCache = ContainerUtil.newConcurrentMap();
+  private final Map<QualifiedName, List<SoftReference<PsiElement>>> myCache = ContainerUtil.newConcurrentMap();
+  private final Map<String, List<QualifiedName>> myQNameCache = ContainerUtil.newConcurrentMap();
 
   public void clearCache() {
     myCache.clear();
@@ -41,10 +43,11 @@ public abstract class PythonPathCache {
 
   @Nullable
   public List<PsiElement> get(QualifiedName qualifiedName) {
-    final List<PsiElement> result = myCache.get(qualifiedName);
-    if (result == null) {
+    final List<SoftReference<PsiElement>> references = myCache.get(qualifiedName);
+    if (references == null) {
       return null;
     }
+    final List<PsiElement> result = references.stream().map(r -> r.get()).filter(p -> p != null).collect(Collectors.toList());
     final boolean staleElementRemoved = result.removeIf(e -> !e.isValid());
     if (staleElementRemoved) {
       Logger.getInstance(PythonPathCache.class).warn("Removing invalid element from cache");
@@ -53,15 +56,21 @@ public abstract class PythonPathCache {
   }
 
   public void put(QualifiedName qualifiedName, List<PsiElement> results) {
-    myCache.put(qualifiedName, new ArrayList<>(results));
+    if (results != null) {
+      myCache.put(qualifiedName, new ArrayList<>(results.stream().map(e -> new SoftReference<>(e)).collect(Collectors.toList())));
+    }
   }
 
+  @Nullable
   public List<QualifiedName> getNames(VirtualFile vFile) {
-    return myQNameCache.get(vFile);
+    if (vFile == null) {
+      return null;
+    }
+    return myQNameCache.get(vFile.getUrl());
   }
 
   public void putNames(VirtualFile vFile, List<QualifiedName> qNames) {
-    myQNameCache.put(vFile, new ArrayList<>(qNames));
+    myQNameCache.put(vFile.getUrl(), new ArrayList<>(qNames));
   }
 
   protected class MyVirtualFileAdapter extends VirtualFileAdapter {