Untangle external reader code (#776)

- move the following classes into package externalreader:
  - ExternalModuleResolver
  - ExternalResourceResolver
  - MessageTransportModuleResolver (renamed to ExternalModuleResolverImpl, made package-private)
  - MessageTransportResourceResolver (renamed to ExternalResourceResolverImpl, made package-private)
- replace interface ExternalModuleResolver.Spec with record ExternalModuleReaderSpec
- replace interface ExternalResourceResolver.Spec with record ExternalResourceReaderSpec
- translate between messaging.ResourceReaderSpec and ExternalResourceReaderSpec (eliminates dependency from messaging on higher layer)
- translate between messaging.ResourceResolverSpec and ExternalResourceResolverSpec (eliminates dependency from messaging on higher layer)
- add ServerMessages.ExternalReader and translate between this message component and the PklEvaluatorSettings.ExternalReader API
- add ServerMessages.Proxy and translate between this message component and the PklEvaluatorSettings.Proxy API
- change type of CreateEvaluatorRequest.allowedModules/allowedResources from List<Pattern>? to List<String>?
  - removes a lot of code
  - should not need to create a Pattern object to send a message
- deprecate method evaluatorSettings.PklEvaluatorSettings.Proxy.create()
  - only seems useful internally, inlined

Co-authored-by: Dan Chao <dan.chao@apple.com>

pkl-core/src/test/kotlin/org/pkl/core/externalreader/ExternalModuleReader.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2025 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,7 +18,7 @@ package org.pkl.core.externalreader
 import java.net.URI
 import org.pkl.core.messaging.Messages.ModuleReaderSpec
 
-/** An external module reader, to be used with [ExternalReaderRuntime]. */
+/** An external module reader, to be used with [ExternalReaderClient]. */
 interface ExternalModuleReader : ExternalReaderBase {
   val isLocal: Boolean
 

pkl-core/src/test/kotlin/org/pkl/core/externalreader/ExternalReaderClient.kt

@@ -19,14 +19,15 @@ import java.io.IOException
 import org.pkl.core.externalreader.ExternalReaderMessages.*
 import org.pkl.core.messaging.Message
 import org.pkl.core.messaging.MessageTransport
+import org.pkl.core.messaging.Messages
 import org.pkl.core.messaging.Messages.*
 import org.pkl.core.messaging.ProtocolException
 import org.pkl.core.util.Nullable
 
 /** An implementation of the client side of the external reader flow */
-class ExternalReaderRuntime(
-  private val moduleReaders: List<ExternalModuleReader>,
-  private val resourceReaders: List<ExternalResourceReader>,
+class ExternalReaderClient(
+  private val externalModuleReaders: List<ExternalModuleReader>,
+  private val externalResourceReaders: List<ExternalResourceReader>,
   private val transport: MessageTransport,
 ) {
   /** Close the runtime and its transport. */
@@ -35,7 +36,7 @@ class ExternalReaderRuntime(
   }
 
   private fun findModuleReader(scheme: String): @Nullable ExternalModuleReader? {
-    for (moduleReader in moduleReaders) {
+    for (moduleReader in externalModuleReaders) {
       if (moduleReader.scheme.equals(scheme, ignoreCase = true)) {
         return moduleReader
       }
@@ -44,7 +45,7 @@ class ExternalReaderRuntime(
   }
 
   private fun findResourceReader(scheme: String): @Nullable ExternalResourceReader? {
-    for (resourceReader in resourceReaders) {
+    for (resourceReader in externalResourceReaders) {
       if (resourceReader.scheme.equals(scheme, ignoreCase = true)) {
         return resourceReader
       }
@@ -72,7 +73,7 @@ class ExternalReaderRuntime(
           Message.Type.INITIALIZE_MODULE_READER_REQUEST -> {
             val req = msg as InitializeModuleReaderRequest
             val reader = findModuleReader(req.scheme)
-            var spec: @Nullable ModuleReaderSpec? = null
+            var spec: Messages.ModuleReaderSpec? = null
             if (reader != null) {
               spec = reader.spec
             }
@@ -81,7 +82,7 @@ class ExternalReaderRuntime(
           Message.Type.INITIALIZE_RESOURCE_READER_REQUEST -> {
             val req = msg as InitializeResourceReaderRequest
             val reader = findResourceReader(req.scheme)
-            var spec: @Nullable ResourceReaderSpec? = null
+            var spec: Messages.ResourceReaderSpec? = null
             if (reader != null) {
               spec = reader.spec
             }

pkl-core/src/test/kotlin/org/pkl/core/externalreader/ExternalResourceReader.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2025 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,7 +18,7 @@ package org.pkl.core.externalreader
 import java.net.URI
 import org.pkl.core.messaging.Messages.ResourceReaderSpec
 
-/** An external resource reader, to be used with [ExternalReaderRuntime]. */
+/** An external resource reader, to be used with [ExternalReaderClient]. */
 interface ExternalResourceReader : ExternalReaderBase {
   fun read(uri: URI): ByteArray
 

pkl-core/src/test/kotlin/org/pkl/core/externalreader/MessagePackCodecTest.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2025 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -23,7 +23,7 @@ import org.msgpack.core.MessagePack
 import org.pkl.core.externalreader.ExternalReaderMessages.*
 import org.pkl.core.messaging.*
 
-class ExternalProcessProcessReaderMessagePackCodecTest {
+class MessagePackCodecTest {
   private val encoder: MessageEncoder
   private val decoder: MessageDecoder
 

pkl-core/src/test/kotlin/org/pkl/core/externalreader/TestExternalModuleReader.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2025 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.

pkl-core/src/test/kotlin/org/pkl/core/externalreader/TestExternalReaderProcess.kt

@@ -25,10 +25,7 @@ import java.util.concurrent.Future
 import kotlin.random.Random
 import org.pkl.core.externalreader.ExternalReaderMessages.*
 import org.pkl.core.messaging.MessageTransport
-import org.pkl.core.messaging.MessageTransportModuleResolver
-import org.pkl.core.messaging.MessageTransportResourceResolver
 import org.pkl.core.messaging.MessageTransports
-import org.pkl.core.messaging.Messages.*
 import org.pkl.core.messaging.ProtocolException
 
 class TestExternalReaderProcess(private val transport: MessageTransport) : ExternalReaderProcess {
@@ -42,11 +39,11 @@ class TestExternalReaderProcess(private val transport: MessageTransport) : Exter
     transport.close()
   }
 
-  override fun getModuleResolver(evaluatorId: Long): MessageTransportModuleResolver =
-    MessageTransportModuleResolver(transport, evaluatorId)
+  override fun getModuleResolver(evaluatorId: Long): ExternalModuleResolver =
+    ExternalModuleResolver.of(transport, evaluatorId)
 
-  override fun getResourceResolver(evaluatorId: Long): MessageTransportResourceResolver =
-    MessageTransportResourceResolver(transport, evaluatorId)
+  override fun getResourceResolver(evaluatorId: Long): ExternalResourceResolver =
+    ExternalResourceResolver.of(transport, evaluatorId)
 
   fun run() {
     try {
@@ -69,7 +66,11 @@ class TestExternalReaderProcess(private val transport: MessageTransport) : Exter
           transport.send(request) { response ->
             when (response) {
               is InitializeModuleReaderResponse -> {
-                complete(response.spec)
+                val spec =
+                  response.spec?.let {
+                    ModuleReaderSpec(it.scheme, it.hasHierarchicalUris, it.isLocal, it.isGlobbable)
+                  }
+                complete(spec)
               }
               else -> completeExceptionally(ProtocolException("unexpected response"))
             }
@@ -86,7 +87,11 @@ class TestExternalReaderProcess(private val transport: MessageTransport) : Exter
           transport.send(request) { response ->
             when (response) {
               is InitializeResourceReaderResponse -> {
-                complete(response.spec)
+                val spec =
+                  response.spec?.let {
+                    ResourceReaderSpec(it.scheme, it.hasHierarchicalUris, it.isGlobbable)
+                  }
+                complete(spec)
               }
               else -> completeExceptionally(ProtocolException("unexpected response"))
             }
@@ -97,9 +102,9 @@ class TestExternalReaderProcess(private val transport: MessageTransport) : Exter
 
   companion object {
     fun initializeTestHarness(
-      moduleReaders: List<ExternalModuleReader>,
-      resourceReaders: List<ExternalResourceReader>,
-    ): Pair<TestExternalReaderProcess, ExternalReaderRuntime> {
+      externalModuleReaders: List<ExternalModuleReader>,
+      externalResourceReaders: List<ExternalResourceReader>,
+    ): Pair<TestExternalReaderProcess, ExternalReaderClient> {
       val rxIn = PipedInputStream(10240)
       val rxOut = PipedOutputStream(rxIn)
       val txIn = PipedInputStream(10240)
@@ -115,13 +120,14 @@ class TestExternalReaderProcess(private val transport: MessageTransport) : Exter
           ExternalReaderMessagePackEncoder(rxOut),
         ) {}
 
-      val runtime = ExternalReaderRuntime(moduleReaders, resourceReaders, clientTransport)
+      val client =
+        ExternalReaderClient(externalModuleReaders, externalResourceReaders, clientTransport)
       val proc = TestExternalReaderProcess(serverTransport)
 
-      Thread(runtime::run).start()
+      Thread(client::run).start()
       Thread(proc::run).start()
 
-      return proc to runtime
+      return proc to client
     }
   }
 }

pkl-core/src/test/kotlin/org/pkl/core/resource/ResourceReadersTest.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2025 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.