Merge pull request #550 from JetBrains/kdoc-inherit

allow inheriting doc comments from base classes

compiler/frontend/src/org/jetbrains/kotlin/kdoc/KDocFinder.kt

@@ -0,0 +1,47 @@
+/*
+ * Copyright 2010-2015 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.kdoc
+
+import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
+import org.jetbrains.kotlin.descriptors.DeclarationDescriptorWithSource
+import org.jetbrains.kotlin.resolve.source.PsiSourceElement
+import org.jetbrains.kotlin.psi.JetDeclaration
+import org.jetbrains.kotlin.descriptors.FunctionDescriptor
+import org.jetbrains.kotlin.kdoc.psi.impl.KDocTag
+
+fun findKDoc(declaration: DeclarationDescriptor): KDocTag? {
+    if (declaration is DeclarationDescriptorWithSource) {
+        val psiDeclaration = (declaration.getSource() as? PsiSourceElement)?.psi?.getNavigationElement()
+        if (psiDeclaration is JetDeclaration) {
+            val kdoc = psiDeclaration.getDocComment()
+            if (kdoc != null) {
+                return kdoc.getDefaultSection()
+            }
+        }
+    }
+
+    if (declaration is FunctionDescriptor) {
+        for (baseDescriptor in declaration.getOverriddenDescriptors()) {
+            val baseKDoc = findKDoc(baseDescriptor)
+            if (baseKDoc != null) {
+                return baseKDoc
+            }
+        }
+    }
+
+    return null
+}