From 45446d263dbff5600616ffe686c425de01c5f349 Mon Sep 17 00:00:00 2001
From: "Maxim.Mossienko" <Maxim.Mossienko@jetbrains.com>
Date: Thu, 5 Nov 2015 00:30:49 +0100
Subject: [PATCH] [performance] for getValues() invokation with Iterable scope
 of single file do call processValueImpl with restrictToFile parameter set,
 thus bypassing possible costly projectIndexableFilter() invokation later

---
 .../util/indexing/FileBasedIndexImpl.java        | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/platform/lang-impl/src/com/intellij/util/indexing/FileBasedIndexImpl.java b/platform/lang-impl/src/com/intellij/util/indexing/FileBasedIndexImpl.java
index f82778573863..e781efb48fbd 100644
--- a/platform/lang-impl/src/com/intellij/util/indexing/FileBasedIndexImpl.java
+++ b/platform/lang-impl/src/com/intellij/util/indexing/FileBasedIndexImpl.java
@@ -875,7 +875,21 @@ public class FileBasedIndexImpl extends FileBasedIndex {
   @NotNull
   public <K, V> List<V> getValues(@NotNull final ID<K, V> indexId, @NotNull K dataKey, @NotNull final GlobalSearchScope filter) {
     final List<V> values = new SmartList<V>();
-    processValuesImpl(indexId, dataKey, true, null, new ValueProcessor<V>() {
+    VirtualFile restrictToFile = null;
+
+    if (filter instanceof Iterable) {
+      final Iterator<VirtualFile> virtualFileIterator = ((Iterable<VirtualFile>)filter).iterator();
+
+      if (virtualFileIterator.hasNext()) {
+        VirtualFile restrictToFileCandidate = virtualFileIterator.next();
+
+        if (!virtualFileIterator.hasNext()) {
+          restrictToFile = restrictToFileCandidate;
+        }
+      }
+    }
+
+    processValuesImpl(indexId, dataKey, true, restrictToFile, new ValueProcessor<V>() {
       @Override
       public boolean process(final VirtualFile file, final V value) {
         values.add(value);