Minor optimization: filter non-relevant roots before searching for kotlin_module files

Author: zarechenskiy

kotlin-eclipse-core/src/org/jetbrains/kotlin/core/resolve/KotlinPackagePartProvider.kt

@@ -1,3 +1,19 @@
+/*******************************************************************************
+* Copyright 2000-2016 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 org.jetbrains.kotlin.core.resolve
 
 import org.jetbrains.kotlin.descriptors.PackagePartProvider
@@ -6,7 +22,7 @@ import org.eclipse.jdt.core.IJavaProject
 import org.jetbrains.kotlin.core.model.KotlinEnvironment
 
 public class KotlinPackagePartProvider(javaProject: IJavaProject) : PackagePartProvider {
-    val roots = KotlinEnvironment.getEnvironment(javaProject).getRoots()
+    val roots = KotlinEnvironment.getEnvironment(javaProject).getRoots().filter { it.findChild("META-INF") != null }
 
     override fun findPackageParts(packageFqName: String): List<String> {
         val pathParts = packageFqName.split('.')
@@ -18,9 +34,9 @@ public class KotlinPackagePartProvider(javaProject: IJavaProject) : PackagePartP
                 else  parent.findChild(part) ?: return@filter false
             }
             true
-        }.map {
+        }.mapNotNull {
             it.findChild("META-INF")
-        }.filterNotNull().flatMap {
+        }.flatMap {
             it.children.filter { it.name.endsWith(ModuleMapping.MAPPING_FILE_EXT) }.toList()
         }.map {
             ModuleMapping.create(it.contentsToByteArray())