1 files changed, 64 insertions, 0 deletions
diff --git a/common-util/src/main/kotlin/com/google/devtools/ksp/IncrementalUtil.kt b/common-util/src/main/kotlin/com/google/devtools/ksp/IncrementalUtil.kt
new file mode 100644
index 00000000..f0c94dc7
--- /dev/null
+++ b/common-util/src/main/kotlin/com/google/devtools/ksp/IncrementalUtil.kt
@@ -0,0 +1,64 @@
+/*
+ * Copyright 2022 Google LLC
+ * Copyright 2010-2022 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ *
+ * 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 com.google.devtools.ksp
+
+import com.google.devtools.ksp.symbol.*
+import java.io.File
+
+abstract class KSVirtualFile(val baseDir: File, val name: String) : KSFile {
+    override val annotations: Sequence<KSAnnotation>
+        get() = throw Exception("$name should not be used.")
+
+    override val declarations: Sequence<KSDeclaration>
+        get() = throw Exception("$name should not be used.")
+
+    override val fileName: String
+        get() = "<$name is a virtual file; DO NOT USE.>"
+
+    override val filePath: String
+        get() = File(baseDir, fileName).path
+
+    override val packageName: KSName
+        get() = throw Exception("$name should not be used.")
+
+    override val origin: Origin
+        get() = throw Exception("$name should not be used.")
+
+    override val location: Location
+        get() = throw Exception("$name should not be used.")
+
+    override val parent: KSNode?
+        get() = throw Exception("$name should not be used.")
+
+    override fun <D, R> accept(visitor: KSVisitor<D, R>, data: D): R {
+        throw Exception("$name should not be used.")
+    }
+}
+
+/**
+ * Used when an output potentially depends on new information.
+ */
+class AnyChanges(baseDir: File) : KSVirtualFile(baseDir, "AnyChanges")
+
+/**
+ * Used for classes from classpath, i.e., classes without source files.
+ */
+class NoSourceFile(baseDir: File, val fqn: String) : KSVirtualFile(baseDir, "NoSourceFile") {
+    override val fileName: String
+        get() = "<NoSourceFile for $fqn is a virtual file; DO NOT USE.>"
+}