Provide exception details

Author: fwcd

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

@@ -17,13 +17,15 @@ 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 DAPExceptionDetails = org.eclipse.lsp4j.debug.ExceptionDetails
 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
+private typealias InternalException = org.javacs.ktda.core.exception.DebuggeeException
 
 /**
  * Handles conversions between debug adapter types
@@ -126,4 +128,12 @@ class DAPConverter(
 		InternalCompletionItemType.REFERENCE -> DAPCompletionItemType.REFERENCE
 		InternalCompletionItemType.CUSTOMCOLOR -> DAPCompletionItemType.CUSTOMCOLOR
 	}
+
+	fun toDAPExceptionDetails(internalException: InternalException): DAPExceptionDetails = DAPExceptionDetails().apply {
+		message = internalException.message
+		typeName = internalException.typeName
+		fullTypeName = internalException.fullTypeName
+		stackTrace = internalException.stackTrace
+		innerException = internalException.innerException?.let(::toDAPExceptionDetails)?.let { arrayOf(it) }
+	}
 }

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

@@ -17,9 +17,11 @@ import org.javacs.kt.LogMessage
 import org.javacs.kt.util.AsyncExecutor
 import org.javacs.ktda.util.JSON_LOG
 import org.javacs.ktda.util.KotlinDAException
+import org.javacs.ktda.util.ObjectPool
 import org.javacs.ktda.util.waitFor
 import org.javacs.ktda.core.Debuggee
 import org.javacs.ktda.core.DebugContext
+import org.javacs.ktda.core.exception.DebuggeeException
 import org.javacs.ktda.core.event.DebuggeeEventBus
 import org.javacs.ktda.core.event.BreakpointStopEvent
 import org.javacs.ktda.core.event.StepStopEvent
@@ -44,6 +46,8 @@ class KotlinDebugAdapter(
 	private var client: IDebugProtocolClient? = null
 	private var converter = DAPConverter()
 	private val context = DebugContext()
+
+	private val exceptionsPool = ObjectPool<Long, DebuggeeException>() // Contains exceptions thrown by the debuggee owned by thread ids
 
 	// TODO: This is a workaround for https://github.com/eclipse/lsp4j/issues/229
 	// For more information, see launch() method
@@ -57,6 +61,7 @@ class KotlinDebugAdapter(
 		val capabilities = Capabilities()
 		capabilities.supportsConfigurationDoneRequest = true
 		capabilities.supportsCompletionsRequest = true
+		capabilities.supportsExceptionInfoRequest = true
 		capabilities.exceptionBreakpointFilters = ExceptionBreakpoint.values()
 			.map(converter::toDAPExceptionBreakpointsFilter)
 			.toTypedArray()
@@ -133,6 +138,7 @@ class KotlinDebugAdapter(
 			sendStopEvent(it.threadID, StoppedEventArgumentsReason.STEP)
 		}
 		eventBus.exceptionListeners.add {
+			exceptionsPool.store(it.threadID, it.exception)
 			sendStopEvent(it.threadID, StoppedEventArgumentsReason.EXCEPTION)
 		}
 		stdoutAsync.execute {
@@ -171,7 +177,7 @@ class KotlinDebugAdapter(
 		client!!.terminated(TerminatedEventArguments())
 		LOG.info("Sent exit event")
 	}
-	
+
 	override fun attach(args: Map<String, Any>) = async.execute {
 		performInitialization()
 
@@ -258,6 +264,7 @@ class KotlinDebugAdapter(
 	override fun continue_(args: ContinueArguments) = async.compute {
 		val success = debuggee!!.threadByID(args.threadId)?.resume()
 		if (success ?: false) {
+			exceptionsPool.clear()
 			converter.variablesPool.clear()
 			converter.stackFramePool.removeAllOwnedBy(args.threadId)
 		}
@@ -333,7 +340,7 @@ class KotlinDebugAdapter(
 				.childs
 				?.map(converter::toDAPVariable)
 				?.toTypedArray()
-				?: emptyArray()
+				.orEmpty()
 		}
 	)
 
@@ -383,7 +390,14 @@ class KotlinDebugAdapter(
 		}
 	}
 
-	override fun exceptionInfo(args: ExceptionInfoArguments): CompletableFuture<ExceptionInfoResponse> = notImplementedDAPMethod()
+	override fun exceptionInfo(args: ExceptionInfoArguments): CompletableFuture<ExceptionInfoResponse> = async.compute {
+		val id = exceptionsPool.getIDsOwnedBy(args.threadId).firstOrNull()
+		val exception = id?.let { exceptionsPool.getByID(it) }
+		ExceptionInfoResponse().apply {
+			exceptionId = id?.toString() ?: ""
+			details = exception?.let(converter::toDAPExceptionDetails)
+		}
+	}
 
 	private fun connectLoggingBackend(client: IDebugProtocolClient) {
 		val backend: (LogMessage) -> Unit = {

adapter/src/main/kotlin/org/javacs/ktda/core/event/ExceptionStopEvent.kt

@@ -1,6 +1,8 @@
 package org.javacs.ktda.core.event
 
+import org.javacs.ktda.core.exception.DebuggeeException
+
 class ExceptionStopEvent(
 	val threadID: Long,
-	val exceptionName: String
+	val exception: DebuggeeException
 )

adapter/src/main/kotlin/org/javacs/ktda/core/exception/DebuggeeException.kt

@@ -0,0 +1,14 @@
+package org.javacs.ktda.core.exception
+
+interface DebuggeeException {
+    val message: String?
+        get() = null
+    val typeName: String?
+        get() = null
+    val fullTypeName: String?
+        get() = null
+    val stackTrace: String?
+        get() = null
+    val innerException: DebuggeeException?
+        get() = null
+}

adapter/src/main/kotlin/org/javacs/ktda/jdi/event/VMEventBus.kt

@@ -4,10 +4,12 @@ import org.javacs.kt.LOG
 import org.javacs.ktda.util.ListenerList
 import org.javacs.ktda.util.Subscription
 import org.javacs.ktda.core.event.DebuggeeEventBus
+import org.javacs.ktda.core.exception.DebuggeeException
 import org.javacs.ktda.core.event.ExitEvent
 import org.javacs.ktda.core.event.BreakpointStopEvent
 import org.javacs.ktda.core.event.ExceptionStopEvent
 import org.javacs.ktda.core.event.StepStopEvent
+import org.javacs.ktda.jdi.exception.JDIException
 import com.sun.jdi.VirtualMachine
 import com.sun.jdi.VMDisconnectedException
 import com.sun.jdi.event.VMDeathEvent
@@ -81,10 +83,9 @@ class VMEventBus(private val vm: VirtualMachine): DebuggeeEventBus {
 			it.resumeThreads = false
 		}
 		subscribe(JDIExceptionEvent::class) {
-			val exception = it.jdiEvent.exception()
 			exceptionListeners.fire(ExceptionStopEvent(
 				threadID = toThreadID(it.jdiEvent),
-				exceptionName = exception.referenceType().name()
+				exception = JDIException(it.jdiEvent.exception(), it.jdiEvent.thread())
 			))
 		}
 	}

adapter/src/main/kotlin/org/javacs/ktda/jdi/exception/JDIException.kt

@@ -0,0 +1,23 @@
+package org.javacs.ktda.jdi.exception
+
+import com.sun.jdi.ObjectReference
+import com.sun.jdi.ThreadReference
+import org.javacs.ktda.core.exception.DebuggeeException
+
+class JDIException(
+    private val exception: ObjectReference,
+    private val thread: ThreadReference
+) : DebuggeeException {
+    private val type by lazy { exception.referenceType() }
+
+    override val fullTypeName: String by lazy { type.name() }
+    override val typeName: String? by lazy { fullTypeName.split(".").last() }
+    override val message: String? by lazy {
+        type.methodsByName("getMessage")
+            .firstOrNull()
+            ?.let { exception.invokeMethod(thread, it, emptyList(), 0) }
+            ?.toString()
+    }
+
+    // TODO: Stack frames, inner exception
+}

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

@@ -44,7 +44,7 @@ class JDIStackFrame(
 					.takeIf { rest.isEmpty() }
 					?.filter { it.name.startsWith(qual) }
 					?.map { CompletionItem(it.name, CompletionItemType.VARIABLE) }
-		} ?: emptyList()
+		}.orEmpty()
 
 	private fun parseQualified(expression: String): List<String> = expression.split(".")
 

adapter/src/main/kotlin/org/javacs/ktda/util/ObjectPool.kt

@@ -62,6 +62,11 @@ class ObjectPool<O, V> {
 	}
 
 	fun getByID(id: Long) = mappingsByID[id]?.value
+
+	fun getIDsOwnedBy(owner: O): Set<Long> = mappingsByOwner[owner]
+		?.map { it.key.id }
+		?.toSet()
+		.orEmpty()
 
 	fun getOwnedBy(owner: O): Set<V> = mappingsByOwner[owner]
 		?.map { it.value }