General override member(s) functionality

server/src/main/kotlin/org/javacs/kt/KotlinProtocolExtensionService.kt

@@ -4,6 +4,8 @@ import org.eclipse.lsp4j.*
 import org.javacs.kt.util.AsyncExecutor
 import org.javacs.kt.util.parseURI
 import org.javacs.kt.resolve.resolveMain
+import org.javacs.kt.position.offset
+import org.javacs.kt.overridemembers.listOverridableMembers
 import java.util.concurrent.CompletableFuture
 import java.nio.file.Paths
 
@@ -39,4 +41,12 @@ class KotlinProtocolExtensionService(
             "projectRoot" to workspacePath
         )
     }
+
+    override fun overrideMember(position: TextDocumentPositionParams): CompletableFuture<List<CodeAction>> = async.compute {
+        val fileUri = parseURI(position.textDocument.uri)
+        val compiledFile = sp.currentVersion(fileUri)
+        val cursorOffset = offset(compiledFile.content, position.position)
+
+        listOverridableMembers(compiledFile, cursorOffset)
+    }
 }

server/src/main/kotlin/org/javacs/kt/KotlinProtocolExtensions.kt

@@ -15,4 +15,7 @@ interface KotlinProtocolExtensions {
 
     @JsonRequest
     fun mainClass(textDocument: TextDocumentIdentifier): CompletableFuture<Map<String, Any?>>
+
+    @JsonRequest
+    fun overrideMember(position: TextDocumentPositionParams): CompletableFuture<List<CodeAction>>
 }

server/src/main/kotlin/org/javacs/kt/codeaction/quickfix/ImplementAbstractMembersQuickFix.kt

@@ -7,6 +7,14 @@ import org.javacs.kt.index.SymbolIndex
 import org.javacs.kt.position.offset
 import org.javacs.kt.position.position
 import org.javacs.kt.util.toPath
+import org.javacs.kt.overridemembers.createFunctionStub
+import org.javacs.kt.overridemembers.createVariableStub
+import org.javacs.kt.overridemembers.getClassDescriptor
+import org.javacs.kt.overridemembers.getDeclarationPadding
+import org.javacs.kt.overridemembers.getNewMembersStartPosition
+import org.javacs.kt.overridemembers.getSuperClassTypeProjections
+import org.javacs.kt.overridemembers.hasNoBody
+import org.javacs.kt.overridemembers.overridesDeclaration
 import org.jetbrains.kotlin.descriptors.ClassDescriptor
 import org.jetbrains.kotlin.descriptors.ClassConstructorDescriptor
 import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
@@ -32,8 +40,6 @@ import org.jetbrains.kotlin.types.KotlinType
 import org.jetbrains.kotlin.types.TypeProjection
 import org.jetbrains.kotlin.types.typeUtil.asTypeProjection
 
-private const val DEFAULT_TAB_SIZE = 4
-
 class ImplementAbstractMembersQuickFix : QuickFix {
     override fun compute(file: CompiledFile, index: SymbolIndex, range: Range, diagnostics: List<Diagnostic>): List<Either<Command, CodeAction>> {
         val diagnostic = findDiagnosticMatch(diagnostics, range)
@@ -108,127 +114,3 @@ private fun getAbstractMembersStubs(file: CompiledFile, kotlinClass: KtClass) =
             null
         }
     }.flatten()
-
-// interfaces are ClassDescriptors by default. When calling AbstractClass super methods, we get a ClassConstructorDescriptor    
-private fun getClassDescriptor(descriptor: DeclarationDescriptor?): ClassDescriptor? = if (descriptor is ClassDescriptor) {
-    descriptor
-} else if (descriptor is ClassConstructorDescriptor) {
-    descriptor.containingDeclaration
-} else {
-    null
-}
-
-private fun getSuperClassTypeProjections(file: CompiledFile, superType: KtSuperTypeListEntry): List<TypeProjection> = superType.typeReference?.typeElement?.children?.filter {
-    it is KtTypeArgumentList
-}?.flatMap {
-    (it as KtTypeArgumentList).arguments
-}?.mapNotNull {
-    (file.referenceExpressionAtPoint(it?.startOffset ?: 0)?.second as? ClassDescriptor)?.defaultType?.asTypeProjection()
-} ?: emptyList()
-
-// Checks if the class overrides the given declaration
-private fun overridesDeclaration(kotlinClass: KtClass, descriptor: FunctionDescriptor): Boolean =
-    kotlinClass.declarations.any {
-        if (it.name == descriptor.name.asString() && it.hasModifier(KtTokens.OVERRIDE_KEYWORD)) {
-            if (it is KtNamedFunction) {
-                parametersMatch(it, descriptor)
-            } else {
-                true
-            }
-        } else {
-            false
-        }
-    }
-
-private fun overridesDeclaration(kotlinClass: KtClass, descriptor: PropertyDescriptor): Boolean =
-    kotlinClass.declarations.any {
-        it.name == descriptor.name.asString() && it.hasModifier(KtTokens.OVERRIDE_KEYWORD)
-    }
-
-// Checks if two functions have matching parameters
-private fun parametersMatch(function: KtNamedFunction, functionDescriptor: FunctionDescriptor): Boolean {
-    if (function.valueParameters.size == functionDescriptor.valueParameters.size) {
-        for (index in 0 until function.valueParameters.size) {
-            if (function.valueParameters[index].name != functionDescriptor.valueParameters[index].name.asString()) {
-                return false
-            } else if (function.valueParameters[index].typeReference?.typeName() != functionDescriptor.valueParameters[index].type.unwrappedType().toString()) {
-                // Note: Since we treat Java overrides as non nullable by default, the above test will fail when the user has made the type nullable.
-                // TODO: look into this
-                return false
-            }
-        }
-
-        if (function.typeParameters.size == functionDescriptor.typeParameters.size) {
-            for (index in 0 until function.typeParameters.size) {
-                if (function.typeParameters[index].variance != functionDescriptor.typeParameters[index].variance) {
-                    return false
-                }
-            }
-        }
-
-        return true
-    }
-
-    return false
-}
-
-private fun KtTypeReference.typeName(): String? = this.name ?: this.typeElement?.children?.filter {
-    it is KtSimpleNameExpression
-}?.map {
-    (it as KtSimpleNameExpression).getReferencedName()
-}?.firstOrNull()
-
-private fun createFunctionStub(function: FunctionDescriptor): String {
-    val name = function.name
-    val arguments = function.valueParameters.map { argument ->
-        val argumentName = argument.name
-        val argumentType = argument.type.unwrappedType()
-
-        "$argumentName: $argumentType"
-    }.joinToString(", ")
-    val returnType = function.returnType?.unwrappedType()?.toString()?.takeIf { "Unit" != it }
-
-    return "override fun $name($arguments)${returnType?.let { ": $it" } ?: ""} { }"
-}
-
-private fun createVariableStub(variable: PropertyDescriptor): String {
-    val variableType = variable.returnType?.unwrappedType()?.toString()?.takeIf { "Unit" != it }
-    return "override val ${variable.name}${variableType?.let { ": $it" } ?: ""} = TODO(\"SET VALUE\")"
-}
-
-// about types: regular Kotlin types are marked T or T?, but types from Java are (T..T?) because nullability cannot be decided.
-// Therefore we have to unpack in case we have the Java type. Fortunately, the Java types are not marked nullable, so we default to non nullable types. Let the user decide if they want nullable types instead. With this implementation Kotlin types also keeps their nullability
-private fun KotlinType.unwrappedType(): KotlinType = this.unwrap().makeNullableAsSpecified(this.isMarkedNullable)
-
-private fun getDeclarationPadding(file: CompiledFile, kotlinClass: KtClass): String {
-    // If the class is not empty, the amount of padding is the same as the one in the last declaration of the class
-    val paddingSize = if (kotlinClass.declarations.isNotEmpty()) {
-        val lastFunctionStartOffset = kotlinClass.declarations.last().startOffset
-        position(file.content, lastFunctionStartOffset).character
-    } else {
-        // Otherwise, we just use a default tab size in addition to any existing padding
-        // on the class itself (note that the class could be inside another class, for example)
-        position(file.content, kotlinClass.startOffset).character + DEFAULT_TAB_SIZE
-    }
-
-    return " ".repeat(paddingSize)
-}
-
-private fun getNewMembersStartPosition(file: CompiledFile, kotlinClass: KtClass): Position? =
-    // If the class is not empty, the new member will be put right after the last declaration
-    if (kotlinClass.declarations.isNotEmpty()) {
-        val lastFunctionEndOffset = kotlinClass.declarations.last().endOffset
-        position(file.content, lastFunctionEndOffset)
-    } else { // Otherwise, the member is put at the beginning of the class
-        val body = kotlinClass.body
-        if (body != null) {
-            position(file.content, body.startOffset + 1)
-        } else {
-            // function has no body. We have to create one. New position is right after entire kotlin class text (with space)
-            val newPosCorrectLine = position(file.content, kotlinClass.startOffset + 1)
-            newPosCorrectLine.character = (kotlinClass.text.length + 2)
-            newPosCorrectLine
-        }
-    }
-
-private fun KtClass.hasNoBody() = null == this.body