Kotlin: Add explorer

java/kotlin-explorer/README

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+
+This shows what is encoded in the kotlin.Metadata section shown in the
+output of `javap -v SomeKotlinClass`.
+
+It is not currently able to extract the information from .class files
+itself; the values are hard coded in src/main/kotlin/Explorer.kt
+
+Run `gradle run` in this directory to run it.
+

java/kotlin-explorer/build.gradle

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+plugins {
+    id 'org.jetbrains.kotlin.jvm' version "${kotlinVersion}"
+    id 'org.jetbrains.dokka' version '1.4.32'
+    id "com.vanniktech.maven.publish" version '0.15.1'
+    id 'application'
+}
+
+group 'com.github.codeql'
+version '0.0.1'
+
+dependencies {
+    implementation "org.jetbrains.kotlin:kotlin-stdlib"
+    implementation "org.jetbrains.kotlinx:kotlinx-metadata-jvm:0.3.0"
+}
+
+repositories {
+    mavenCentral()
+}
+
+tasks.withType(org.jetbrains.kotlin.gradle.tasks.KotlinCompile).configureEach {
+    kotlinOptions {
+        jvmTarget = "1.8"
+    }
+}
+
+application {
+    mainClass = 'com.github.codeql.ExplorerKt'
+}

java/kotlin-explorer/gradle.properties

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+kotlin.code.style=official
+kotlinVersion=1.5.21
+
+GROUP=com.github.codeql
+VERSION_NAME=0.0.1
+POM_DESCRIPTION=CodeQL Kotlin explorer
+

java/kotlin-explorer/settings.gradle

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+pluginManagement {
+    repositories {
+        mavenCentral()
+        gradlePluginPortal()
+    }
+}
+
+rootProject.name = 'codeql-kotlin-explorer'

java/kotlin-explorer/src/main/kotlin/Explorer.kt

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+package com.github.codeql
+import kotlinx.metadata.internal.metadata.jvm.deserialization.JvmMetadataVersion
+import kotlinx.metadata.jvm.*
+import kotlinx.metadata.*
+
+fun main(args : Array<String>) {
+    /*
+    Values from `javap -v` on TestKt.class from:
+
+    class MyClass {}
+
+    class MyParamClass<T> {}
+
+    fun f(x: MyClass, y: MyClass?,
+          l1: MyParamClass<MyClass>,
+          l2: MyParamClass<MyClass?>,
+          l3: MyParamClass<MyClass>?,
+          l4: MyParamClass<MyClass?>?) {
+    }
+    */
+    val kind = 2
+    val metadataVersion = intArrayOf(1, 5, 1)
+    val data1 = arrayOf("\u0000\u0018\n\u0000\n\u0002\u0010\u0002\n\u0000\n\u0002\u0018\u0002\n\u0002\b\u0002\n\u0002\u0018\u0002\n\u0002\b\u0003\u001aX\u0010\u0000\u001a\u00020\u00012\u0006\u0010\u0002\u001a\u00020\u00032\b\u0010\u0004\u001a\u0004\u0018\u00010\u00032\u000c\u0010\u0005\u001a\b\u0012\u0004\u0012\u00020\u00030\u00062\u000e\u0010\u0007\u001a\n\u0012\u0006\u0012\u0004\u0018\u00010\u00030\u00062\u000e\u0010\b\u001a\n\u0012\u0004\u0012\u00020\u0003\u0018\u00010\u00062\u0010\u0010\t\u001a\u000c\u0012\u0006\u0012\u0004\u0018\u00010\u0003\u0018\u00010\u0006")
+    val data2 = arrayOf("f","","x","LMyClass;","y","l1","LMyParamClass;","l2","l3","l4")
+    val extraString = null
+    val packageName = null
+    val extraInt = 48
+    val kch = KotlinClassHeader(kind, metadataVersion, data1, data2, extraString, packageName, extraInt)
+
+    val md = KotlinClassMetadata.read(kch)
+    when (md) {
+        is KotlinClassMetadata.Class -> println("Metadata for Class not yet supported")
+        is KotlinClassMetadata.FileFacade -> {
+            println("Metadata for FileFacade:")
+            val kmp = md.toKmPackage()
+            kmp.accept(MyPackageVisitor(0))
+        }
+        is KotlinClassMetadata.SyntheticClass -> println("Metadata for SyntheticClass not yet supported")
+        is KotlinClassMetadata.MultiFileClassFacade -> println("Metadata for MultiFileClassFacade not yet supported")
+        is KotlinClassMetadata.MultiFileClassPart -> println("Metadata for MultiFileClassPart not yet supported")
+        is KotlinClassMetadata.Unknown -> println("Unknown kind")
+        else -> println("Unexpected kind")
+    }
+}
+
+fun pr(indent: Int, s: String) {
+    println("    ".repeat(indent) + s)
+}
+
+class MyPackageVisitor(val indent: Int): KmPackageVisitor() {
+    override fun visitFunction(flags: Flags, name: String): KmFunctionVisitor? {
+        pr(indent, "=> Function; flags:$flags, name:$name")
+        return MyFunctionVisitor(indent + 1)
+    }
+
+    override fun visitProperty(flags: Flags, name: String, getterFlags: Flags, setterFlags: Flags): KmPropertyVisitor? {
+        pr(indent, "=> Properties not yet handled")
+        return null
+    }
+
+    override fun visitTypeAlias(flags: Flags, name: String): KmTypeAliasVisitor? {
+        pr(indent, "=> Type aliases not yet handled")
+        return null
+    }
+
+    override fun visitExtensions(type: KmExtensionType): KmPackageExtensionVisitor? {
+        pr(indent, "=> Package extensions; type:$type")
+        when (type) {
+            JvmPackageExtensionVisitor.TYPE -> return MyJvmPackageExtensionVisitor(indent + 1)
+            else -> {
+                pr(indent, "- Not yet handled")
+                return null
+            }
+        }
+    }
+}
+
+class MyFunctionVisitor(val indent: Int): KmFunctionVisitor() {
+    override fun visitTypeParameter(flags: Flags, name: String, id: Int, variance: KmVariance): KmTypeParameterVisitor? {
+        pr(indent, "=> Type parameter; flags:$flags, name:$name, id:$id, variance:$variance")
+        pr(indent, "    -> Not yet handled")
+        return null
+    }
+    override fun visitReceiverParameterType(flags: Flags): KmTypeVisitor? {
+        pr(indent, "=> Receiver parameter type; flags:$flags")
+        pr(indent, "    -> Not yet handled")
+        return null
+    }
+
+    override fun visitValueParameter(flags: Flags, name: String): KmValueParameterVisitor? {
+        pr(indent, "=> Value parameter; flags:$flags, name:$name")
+        return MyValueParameterVisitor(indent + 1)
+    }
+
+    override fun visitReturnType(flags: Flags): KmTypeVisitor? {
+        pr(indent, "=> Return type; flags:$flags")
+        return MyTypeVisitor(indent + 1)
+    }
+
+    override fun visitVersionRequirement(): KmVersionRequirementVisitor? {
+        pr(indent, "=> VersionRequirement not yet handled")
+        return null
+    }
+
+    override fun visitContract(): KmContractVisitor? {
+        pr(indent, "=> Contract not yet handled")
+        return null
+    }
+
+    override fun visitExtensions(type: KmExtensionType): KmFunctionExtensionVisitor? {
+        pr(indent, "=> Function extensions; type:$type")
+        when (type) {
+            JvmFunctionExtensionVisitor.TYPE -> return MyJvmFunctionExtensionVisitor(indent + 1)
+            else -> {
+                pr(indent, "- Not yet handled")
+                return null
+            }
+        }
+    }
+}
+
+class MyValueParameterVisitor(val indent: Int): KmValueParameterVisitor() {
+    override fun visitType(flags: Flags): KmTypeVisitor? {
+        pr(indent, "=> Type; flags:$flags")
+        return MyTypeVisitor(indent + 1)
+    }
+
+    override fun visitVarargElementType(flags: Flags): KmTypeVisitor? {
+        pr(indent, "=> VarargElementType not yet handled")
+        return null
+    }
+
+    override fun visitExtensions(type: KmExtensionType): KmValueParameterExtensionVisitor? {
+        pr(indent, "=> Value parameter extensions; type:$type; not yet handled")
+        return null
+    }
+}
+
+class MyTypeVisitor(val indent: Int): KmTypeVisitor() {
+    override fun visitClass(name: ClassName) {
+        pr(indent, "=> Class; name:$name")
+    }
+
+    override fun visitTypeAlias(name: ClassName) {
+        pr(indent, "=> Type alias; name:$name")
+    }
+
+    override fun visitTypeParameter(id: Int) {
+        pr(indent, "=> Type parameter; id:$id")
+    }
+
+    override fun visitArgument(flags: Flags, variance: KmVariance): KmTypeVisitor? {
+        pr(indent, "=> Argument; flags:$flags, variance:$variance")
+        return MyTypeVisitor(indent + 1)
+    }
+
+    override fun visitStarProjection() {
+        pr(indent, "=> Star projection")
+    }
+
+    override fun visitAbbreviatedType(flags: Flags): KmTypeVisitor? {
+        pr(indent, "=> AbbreviatedType not yet handled")
+        return null
+    }
+
+    override fun visitOuterType(flags: Flags): KmTypeVisitor? {
+        pr(indent, "=> OuterType not yet handled")
+        return null
+    }
+
+    override fun visitFlexibleTypeUpperBound(flags: Flags, typeFlexibilityId: String?): KmTypeVisitor? {
+        pr(indent, "=> FlexibleTypeUpperBound not yet handled")
+        return null
+    }
+
+    override fun visitExtensions(type: KmExtensionType): KmTypeExtensionVisitor? {
+        pr(indent, "=> Type extensions; type:$type")
+        when (type) {
+            JvmTypeExtensionVisitor.TYPE -> return MyJvmTypeExtensionVisitor(indent + 1)
+            else -> {
+                pr(indent, "- Not yet handled")
+                return null
+            }
+        }
+    }
+}
+
+class MyJvmTypeExtensionVisitor(val indent: Int): JvmTypeExtensionVisitor() {
+    override fun visit(isRaw: Boolean) {
+        pr(indent, "=> isRaw:$isRaw")
+    }
+
+    override fun visitAnnotation(annotation: KmAnnotation) {
+        pr(indent, "=> Annotation; annotation:$annotation")
+    }
+}
+
+class MyJvmPackageExtensionVisitor(val indent: Int): JvmPackageExtensionVisitor() {
+    override fun visitLocalDelegatedProperty(flags: Flags, name: String, getterFlags: Flags, setterFlags: Flags): KmPropertyVisitor? {
+        pr(indent, "=> Local delegate not yet handled")
+        return null
+    }
+
+    override fun visitModuleName(name: String) {
+        pr(indent, "=> Module name; name:$name")
+    }
+}
+
+class MyJvmFunctionExtensionVisitor(val indent: Int): JvmFunctionExtensionVisitor() {
+    override fun visit(signature: JvmMethodSignature?) {
+        pr(indent, "=> signature:$signature")
+    }
+
+    override fun visitLambdaClassOriginName(internalName: String) {
+        pr(indent, "=> LambdaClassOriginName; internalName:$internalName")
+    }
+}