same directory proximity weigher for use in non-IDEA IDEs

platform/lang-impl/src/com/intellij/psi/util/proximity/SameDirectoryWeigher.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright 2000-2010 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.intellij.psi.util.proximity;
+
+import com.intellij.openapi.util.NullableLazyKey;
+import com.intellij.psi.PsiDirectory;
+import com.intellij.psi.PsiElement;
+import com.intellij.psi.util.ProximityLocation;
+import com.intellij.psi.util.PsiTreeUtil;
+import com.intellij.util.NullableFunction;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * NOTE: This class is only registered in platform-based IDEs. In IDEA, SamePackageWeigher is used instead.
+ *
+ * @author yole
+ */
+public class SameDirectoryWeigher extends ProximityWeigher {
+  private static final NullableLazyKey<PsiDirectory, ProximityLocation>
+    PLACE_DIRECTORY = NullableLazyKey.create("placeDirectory", new NullableFunction<ProximityLocation, PsiDirectory>() {
+    @Override
+    public PsiDirectory fun(ProximityLocation location) {
+      return PsiTreeUtil.getParentOfType(location.getPosition(), PsiDirectory.class, false);
+    }
+  });
+
+  public Comparable weigh(@NotNull final PsiElement element, final ProximityLocation location) {
+    final PsiDirectory placeDirectory = PLACE_DIRECTORY.getValue(location);
+    if (placeDirectory == null) {
+      return false;
+    }
+
+    return placeDirectory.equals(PsiTreeUtil.getParentOfType(element, PsiDirectory.class, false));
+  }
+}

platform/platform-resources/src/META-INF/PlatformLangPlugin.xml

@@ -80,6 +80,8 @@
 
     <checkoutCompletedListener implementation="com.intellij.openapi.vcs.checkout.PlatformProjectCheckoutListener"/>
 
+    <weigher key="proximity" implementationClass="com.intellij.psi.util.proximity.SameDirectoryWeigher" id="sameDirectory"
+             order="after openedInEditor"/>
   </extensions>
 
   <xi:include href="xdebugger.xml" xpointer="xpointer(/root/*)"/>