Implement expression completions

Author: fwcd

adapter/src/main/kotlin/org/javacs/ktda/adapter/DAPConverter.kt

@@ -15,11 +15,15 @@ private typealias DAPScope = org.eclipse.lsp4j.debug.Scope
 private typealias DAPVariable = org.eclipse.lsp4j.debug.Variable
 private typealias DAPThread = org.eclipse.lsp4j.debug.Thread
 private typealias DAPExceptionBreakpointsFilter = org.eclipse.lsp4j.debug.ExceptionBreakpointsFilter
+private typealias DAPCompletionItem = org.eclipse.lsp4j.debug.CompletionItem
+private typealias DAPCompletionItemType = org.eclipse.lsp4j.debug.CompletionItemType
 private typealias InternalSource = org.javacs.ktda.core.Source
 private typealias InternalSourceBreakpoint = org.javacs.ktda.core.breakpoint.SourceBreakpoint
 private typealias InternalExceptionBreakpoint = org.javacs.ktda.core.breakpoint.ExceptionBreakpoint
 private typealias InternalBreakpoint = org.javacs.ktda.core.breakpoint.Breakpoint
 private typealias InternalStackFrame = org.javacs.ktda.core.stack.StackFrame
+private typealias InternalCompletionItem = org.javacs.ktda.core.completion.CompletionItem
+private typealias InternalCompletionItemType = org.javacs.ktda.core.completion.CompletionItemType
 
 /**
  * Handles conversions between debug adapter types
@@ -95,4 +99,31 @@ class DAPConverter(
 		name = internalThread.name
 		id = internalThread.id
 	}
+
+	fun toDAPCompletionItem(internalItem: InternalCompletionItem) = DAPCompletionItem().apply {
+		label = internalItem.label
+		type = toDAPCompletionItemType(internalItem.type)
+	}
+	
+	fun toDAPCompletionItemType(internalType: InternalCompletionItemType) = when (internalType) {
+		InternalCompletionItemType.METHOD -> DAPCompletionItemType.METHOD
+		InternalCompletionItemType.FUNCTION -> DAPCompletionItemType.FUNCTION
+		InternalCompletionItemType.CONSTRUCTOR -> DAPCompletionItemType.CONSTRUCTOR
+		InternalCompletionItemType.FIELD -> DAPCompletionItemType.FIELD
+		InternalCompletionItemType.VARIABLE -> DAPCompletionItemType.VARIABLE
+		InternalCompletionItemType.CLASS -> DAPCompletionItemType.CLASS
+		InternalCompletionItemType.INTERFACE -> DAPCompletionItemType.INTERFACE
+		InternalCompletionItemType.MODULE -> DAPCompletionItemType.MODULE
+		InternalCompletionItemType.PROPERTY -> DAPCompletionItemType.PROPERTY
+		InternalCompletionItemType.UNIT -> DAPCompletionItemType.UNIT
+		InternalCompletionItemType.VALUE -> DAPCompletionItemType.VALUE
+		InternalCompletionItemType.ENUM -> DAPCompletionItemType.ENUM
+		InternalCompletionItemType.KEYWORD -> DAPCompletionItemType.KEYWORD
+		InternalCompletionItemType.SNIPPET -> DAPCompletionItemType.SNIPPET
+		InternalCompletionItemType.TEXT -> DAPCompletionItemType.TEXT
+		InternalCompletionItemType.COLOR -> DAPCompletionItemType.COLOR
+		InternalCompletionItemType.FILE -> DAPCompletionItemType.FILE
+		InternalCompletionItemType.REFERENCE -> DAPCompletionItemType.REFERENCE
+		InternalCompletionItemType.CUSTOMCOLOR -> DAPCompletionItemType.CUSTOMCOLOR
+	}
 }

adapter/src/main/kotlin/org/javacs/ktda/adapter/KotlinDebugAdapter.kt

@@ -56,6 +56,7 @@ class KotlinDebugAdapter(
 
 		val capabilities = Capabilities()
 		capabilities.supportsConfigurationDoneRequest = true
+		capabilities.supportsCompletionsRequest = true
 		capabilities.exceptionBreakpointFilters = ExceptionBreakpoint.values()
 			.map(converter::toDAPExceptionBreakpointsFilter)
 			.toTypedArray()
@@ -371,7 +372,16 @@ class KotlinDebugAdapter(
 
 	override fun gotoTargets(args: GotoTargetsArguments): CompletableFuture<GotoTargetsResponse> = notImplementedDAPMethod()
 
-	override fun completions(args: CompletionsArguments): CompletableFuture<CompletionsResponse> = notImplementedDAPMethod()
+	override fun completions(args: CompletionsArguments): CompletableFuture<CompletionsResponse> = async.compute {
+		CompletionsResponse().apply {
+			targets = (args.frameId
+				.let(converter::toInternalStackFrame)
+					?: throw KotlinDAException("Could not find stack frame with ID ${args.frameId}"))
+				.completions(args.text)
+				.map(converter::toDAPCompletionItem)
+				.toTypedArray()
+		}
+	}
 
 	override fun exceptionInfo(args: ExceptionInfoArguments): CompletableFuture<ExceptionInfoResponse> = notImplementedDAPMethod()
 

adapter/src/main/kotlin/org/javacs/ktda/core/completion/CompletionItem.kt

@@ -0,0 +1,6 @@
+package org.javacs.ktda.core.completion
+
+data class CompletionItem(
+    val label: String,
+    val type: CompletionItemType
+)

adapter/src/main/kotlin/org/javacs/ktda/core/completion/CompletionItemType.kt

@@ -0,0 +1,23 @@
+package org.javacs.ktda.core.completion
+
+enum class CompletionItemType {
+    METHOD,
+    FUNCTION,
+    CONSTRUCTOR,
+    FIELD,
+    VARIABLE,
+    CLASS,
+    INTERFACE,
+    MODULE,
+    PROPERTY,
+    UNIT,
+    VALUE,
+    ENUM,
+    KEYWORD,
+    SNIPPET,
+    TEXT,
+    COLOR,
+    FILE,
+    REFERENCE,
+    CUSTOMCOLOR
+}

adapter/src/main/kotlin/org/javacs/ktda/core/stack/StackFrame.kt

@@ -1,6 +1,7 @@
 package org.javacs.ktda.core.stack
 
 import org.javacs.ktda.core.Position
+import org.javacs.ktda.core.completion.CompletionItem
 import org.javacs.ktda.core.scope.VariableTreeNode
 
 interface StackFrame {
@@ -9,4 +10,6 @@ interface StackFrame {
 	val scopes: List<VariableTreeNode>
 
 	fun evaluate(expression: String): VariableTreeNode?
+
+	fun completions(expression: String): List<CompletionItem>
 }

adapter/src/main/kotlin/org/javacs/ktda/jdi/stack/JDIStackFrame.kt

@@ -1,6 +1,8 @@
 package org.javacs.ktda.jdi.stack
 
 import org.javacs.ktda.core.Position
+import org.javacs.ktda.core.completion.CompletionItem
+import org.javacs.ktda.core.completion.CompletionItemType
 import org.javacs.ktda.core.scope.VariableTreeNode
 import org.javacs.ktda.core.stack.StackFrame
 import org.javacs.ktda.jdi.JDISessionContext
@@ -17,18 +19,35 @@ class JDIStackFrame(
 		JDILocalScope(frame)
 	) }
 
+	private val variables by lazy { scopes.flatMap { it.childs ?: emptyList() } }
+
 	// TODO: Scope "Fields"
 	// TODO: Argument values?
 
-	private fun evaluateQualified(qualName: List<String>, variables: List<VariableTreeNode> = scopes.flatMap { it.childs ?: emptyList() }): VariableTreeNode? =
+	private fun evaluateQualified(qualName: List<String>, scopeVariables: List<VariableTreeNode> = variables): VariableTreeNode? =
 		qualName.firstOrNull().let { qual ->
 			val rest = qualName.drop(1)
-			variables
+			scopeVariables
 				.filter { it.name == qual }
 				.mapNotNull { if (rest.isEmpty()) it else evaluateQualified(rest, it.childs ?: emptyList()) }
 				.firstOrNull()
 		}
 
+	private fun completeQualified(qualName: List<String>, scopeVariables: List<VariableTreeNode> = variables): List<CompletionItem> =
+		qualName.firstOrNull()?.let { qual ->
+			val rest = qualName.drop(1)
+			scopeVariables
+				.filter { it.name == qual }
+				.flatMap { completeQualified(rest, it.childs ?: emptyList()) }
+				.takeIf { it.isNotEmpty() }
+				?: scopeVariables
+					.takeIf { rest.isEmpty() }
+					?.filter { it.name.startsWith(qual) }
+					?.map { CompletionItem(it.name, CompletionItemType.VARIABLE) }
+		} ?: emptyList()
+
+	private fun parseQualified(expression: String): List<String> = expression.split(".")
+
 	override fun evaluate(expression: String): VariableTreeNode? {
 		// TODO: Implement proper expression parsing
 		//
@@ -43,8 +62,13 @@ class JDIStackFrame(
 		// Creating JDI values from primitives and strings is possible though,
 		// using VirtualMachine.mirrorOf.
 
-		val qualified = expression.split(".")
+		val qualified = parseQualified(expression)
 		return evaluateQualified(qualified)
 			?: evaluateQualified(listOf("this") + qualified)
 	}
+
+	override fun completions(expression: String): List<CompletionItem> {
+		val qualified = parseQualified(expression)
+		return completeQualified(qualified) + completeQualified(listOf("this") + qualified)
+	}
 }