Implement overriders search

annotations/com/intellij/psi/annotations.xml

@@ -1,4 +1,7 @@
 <root>
+  <item name='com.intellij.psi.JavaPsiFacade com.intellij.psi.JavaPsiFacade getInstance(com.intellij.openapi.project.Project)'>
+    <annotation name='org.jetbrains.annotations.NotNull'/>
+  </item>
   <item name='com.intellij.psi.PsiDocumentManager com.intellij.psi.PsiDocumentManager getInstance(com.intellij.openapi.project.Project)'>
     <annotation name='org.jetbrains.annotations.NotNull'/>
   </item>

compiler/frontend/src/org/jetbrains/jet/lang/psi/psiUtil/jetPsiUtil.kt

@@ -37,6 +37,8 @@ import org.jetbrains.jet.lang.psi.JetPsiFactory
 import kotlin.test.assertTrue
 import com.intellij.psi.search.SearchScope
 import com.intellij.psi.search.PsiSearchScopeUtil
+import org.jetbrains.jet.lang.psi.JetClassBody
+import org.jetbrains.jet.lang.psi.JetParameterList
 
 fun PsiElement.getParentByTypesAndPredicate<T: PsiElement>(
         strict : Boolean = false, vararg parentClasses : Class<T>, predicate: (T) -> Boolean
@@ -156,3 +158,16 @@ fun SearchScope.contains(element: PsiElement): Boolean = PsiSearchScopeUtil.isIn
 fun JetClass.isInheritable(): Boolean {
     return isTrait() || hasModifier(JetTokens.OPEN_KEYWORD)
 }
+
+fun JetDeclaration.isOverridable(): Boolean {
+    val parent = getParent()
+    if (!(parent is JetClassBody || parent is JetParameterList)) return false
+
+    val klass = parent.getParent()
+    if (!(klass is JetClass && klass.isInheritable())) return false
+
+    if (hasModifier(JetTokens.FINAL_KEYWORD) || hasModifier(JetTokens.PRIVATE_KEYWORD)) return false
+
+    return klass.isTrait() ||
+        hasModifier(JetTokens.ABSTRACT_KEYWORD) || hasModifier(JetTokens.OPEN_KEYWORD) || hasModifier(JetTokens.OVERRIDE_KEYWORD)
+}

idea/src/org/jetbrains/jet/plugin/search/declarationsSearch/overridersSearch.kt

@@ -0,0 +1,116 @@
+/*
+ * Copyright 2010-2013 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.jet.plugin.search.declarationsSearch
+
+import com.intellij.psi.PsiMethod
+import com.intellij.psi.util.PsiUtil
+import org.jetbrains.jet.lang.psi.JetDeclaration
+import com.intellij.psi.PsiElement
+import com.intellij.util.Processor
+import com.intellij.util.Query
+import com.intellij.psi.search.GlobalSearchScope
+import java.util.HashMap
+import org.jetbrains.jet.lang.psi.psiUtil.*
+import org.jetbrains.jet.lang.psi.JetNamedFunction
+import java.util.Collections
+import org.jetbrains.jet.asJava.LightClassUtil
+import org.jetbrains.jet.lang.psi.JetProperty
+import org.jetbrains.jet.lang.psi.JetPropertyAccessor
+import com.intellij.psi.PsiClass
+import org.jetbrains.jet.lang.psi.JetParameter
+import com.intellij.psi.util.TypeConversionUtil
+import com.intellij.psi.PsiSubstitutor
+import com.intellij.psi.util.MethodSignatureUtil
+import com.intellij.psi.PsiModifier
+import com.intellij.psi.JavaPsiFacade
+import com.intellij.psi.search.searches.DirectClassInheritorsSearch
+import com.intellij.util.EmptyQuery
+import com.intellij.util.MergeQuery
+import com.intellij.util.UniqueResultsQuery
+import com.intellij.util.containers.ContainerUtil
+
+fun PsiElement.isOverridableElement(): Boolean = when (this) {
+    is PsiMethod -> PsiUtil.canBeOverriden(this)
+    is JetDeclaration -> isOverridable()
+    else -> false
+}
+
+public fun HierarchySearchRequest<PsiElement>.searchOverriders(): Query<PsiMethod> {
+    val psiMethods: List<PsiMethod> = when (originalElement) {
+        is JetNamedFunction -> Collections.singletonList(LightClassUtil.getLightClassMethod(originalElement))
+        is JetProperty -> LightClassUtil.getLightClassPropertyMethods(originalElement).iterator().toArrayList()
+        is JetParameter -> LightClassUtil.getLightClassPropertyMethods(originalElement).iterator().toArrayList()
+        is JetPropertyAccessor -> Collections.singletonList(LightClassUtil.getLightClassAccessorMethod(originalElement))
+        is PsiMethod -> Collections.singletonList(originalElement)
+        else -> return EmptyQuery.getEmptyQuery()
+    }
+    return psiMethods
+            .map { psiMethod -> KotlinPsiMethodOverridersSearch.search(copy(psiMethod)) }
+            .reduce {(query1, query2) -> MergeQuery(query1, query2)}
+}
+
+public object KotlinPsiMethodOverridersSearch : HierarchySearch<PsiMethod>(PsiMethodOverridingHierarchyTraverser) {
+    fun searchDirectOverriders(psiMethod: PsiMethod): Iterable<PsiMethod> {
+        fun PsiMethod.isAcceptable(inheritor: PsiClass, baseMethod: PsiMethod, baseClass: PsiClass): Boolean =
+                when {
+                    hasModifierProperty(PsiModifier.STATIC) -> false
+                    baseMethod.hasModifierProperty(PsiModifier.PACKAGE_LOCAL) ->
+                        JavaPsiFacade.getInstance(getProject()).arePackagesTheSame(baseClass, inheritor)
+                    else -> true
+                }
+
+        val psiClass = psiMethod.getContainingClass()
+        if (psiClass == null) return Collections.emptyList()
+
+        val classToMethod = HashMap<PsiClass, PsiMethod>()
+        val classTraverser = object : HierarchyTraverser<PsiClass> {
+            override fun nextElements(current: PsiClass): Iterable<PsiClass> =
+                    DirectClassInheritorsSearch.search(
+                            aClass = current,
+                            scope = GlobalSearchScope.allScope(current.getProject()),
+                            checkInheritance = true,
+                            includeAnonymous = true
+                    )
+
+            override fun shouldDescend(element: PsiClass): Boolean =
+                    element.isInheritable() && !classToMethod.containsKey(element)
+        }
+
+        classTraverser.forEach(psiClass) { inheritor ->
+            val substitutor = TypeConversionUtil.getSuperClassSubstitutor(psiClass, inheritor, PsiSubstitutor.EMPTY)
+            val signature = psiMethod.getSignature(substitutor)
+            val candidate = MethodSignatureUtil.findMethodBySuperSignature(inheritor, signature, false)
+            if (candidate != null && candidate.isAcceptable(inheritor, psiMethod, psiClass)) {
+                classToMethod.put(inheritor, candidate)
+            }
+        }
+
+        return classToMethod.values()
+    }
+
+    protected override fun isApplicable(request: HierarchySearchRequest<PsiMethod>): Boolean =
+            request.originalElement.isOverridableElement()
+
+    override fun doSearchDirect(request: HierarchySearchRequest<PsiMethod>, consumer: Processor<PsiMethod>) {
+        searchDirectOverriders(request.originalElement).forEach { method -> consumer.process(method) }
+    }
+}
+
+object PsiMethodOverridingHierarchyTraverser: HierarchyTraverser<PsiMethod> {
+    override fun nextElements(current: PsiMethod): Iterable<PsiMethod> = KotlinPsiMethodOverridersSearch.searchDirectOverriders(current)
+    override fun shouldDescend(element: PsiMethod): Boolean = PsiUtil.canBeOverriden(element)
+}