LocalHistory: small optimization

platform/lvcs-impl/src/com/intellij/history/core/tree/DirectoryEntry.java

@@ -24,6 +24,7 @@ import java.io.DataInput;
 import java.io.DataOutput;
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.List;
 
 public class DirectoryEntry extends Entry {
@@ -64,21 +65,30 @@ public class DirectoryEntry extends Entry {
 
   @Override
   public void addChild(Entry child) {
-    checkDoesNotExist(child, child.getName());
+    if (!checkDoesNotExist(child, child.getName())) return;
     unsafeAddChild(child);
   }
 
+  public void addChildren(Collection<Entry> children) {
+    myChildren.ensureCapacity(myChildren.size() + children.size());
+    for (Entry each : children) {
+      unsafeAddChild(each);
+    }
+  }
+
   private void unsafeAddChild(Entry child) {
     myChildren.add(child);
     child.setParent(this);
   }
 
-  protected void checkDoesNotExist(Entry e, String name) {
+  protected boolean checkDoesNotExist(Entry e, String name) {
     Entry found = findChild(name);
-    if (found == null || found == e) return;
+    if (found == null) return true;
+    if (found == e) return false;
 
     removeChild(found);
     LocalHistoryLog.LOG.warn(String.format("entry '%s' already exists in '%s'", name, getPath()));
+    return true;
   }
 
   @Override
@@ -171,7 +181,7 @@ public class DirectoryEntry extends Entry {
   @Override
   protected void collectDeletedDifferences(List<Difference> result) {
     result.add(new Difference(false, this, null));
-    
+
     for (Entry child : myChildren) {
       child.collectDeletedDifferences(result);
     }

platform/lvcs-impl/src/com/intellij/history/core/tree/Entry.java

@@ -26,6 +26,7 @@ import java.io.DataInput;
 import java.io.DataOutput;
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 
@@ -114,6 +115,10 @@ public abstract class Entry {
     throw new UnsupportedOperationException(formatAddRemove(child));
   }
 
+  public void addChildren(Collection<Entry> children) {
+    throw new UnsupportedOperationException();
+  }
+
   public void removeChild(Entry child) {
     throw new UnsupportedOperationException(formatAddRemove(child));
   }

platform/lvcs-impl/src/com/intellij/history/integration/IdeaGateway.java

@@ -37,16 +37,14 @@ import com.intellij.openapi.util.Pair;
 import com.intellij.openapi.vfs.*;
 import com.intellij.openapi.vfs.newvfs.ManagingFS;
 import com.intellij.openapi.vfs.newvfs.NewVirtualFile;
+import com.intellij.util.NullableFunction;
 import com.intellij.util.containers.ContainerUtil;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 import java.io.IOException;
 import java.io.UnsupportedEncodingException;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collections;
-import java.util.List;
+import java.util.*;
 
 public class IdeaGateway {
   private static final Key<ContentAndTimestamps> SAVED_DOCUMENT_CONTENT_AND_STAMP_KEY
@@ -137,8 +135,8 @@ public class IdeaGateway {
     return result;
   }
 
-  public static Iterable<VirtualFile> iterateDBChildren(VirtualFile f) {
-    if (!(f instanceof NewVirtualFile)) return ContainerUtil.emptyIterable();
+  public static Collection<VirtualFile> iterateDBChildren(VirtualFile f) {
+    if (!(f instanceof NewVirtualFile)) return Collections.emptyList();
     NewVirtualFile nf = (NewVirtualFile)f;
     return nf.getCachedChildren();
   }
@@ -184,11 +182,14 @@ public class IdeaGateway {
     return newDir;
   }
 
-  private void doCreateChildren(DirectoryEntry parent, Iterable<VirtualFile> children, boolean forDeletion) {
-    for (VirtualFile each : children) {
-      Entry child = doCreateEntry(each, forDeletion);
-      if (child != null) parent.addChild(child);
-    }
+  private void doCreateChildren(DirectoryEntry parent, Collection<VirtualFile> children, final boolean forDeletion) {
+    List<Entry> entries = ContainerUtil.mapNotNull(children, new NullableFunction<VirtualFile, Entry>() {
+      @Override
+      public Entry fun(VirtualFile each) {
+        return doCreateEntry(each, forDeletion);
+      }
+    });
+    parent.addChildren(entries);
   }
 
   public void registerUnsavedDocuments(final LocalHistoryFacade vcs) {