Fallback to CoreJarFileSystem when JDK doesn't support buffers unmapping

compiler/cli/src/org/jetbrains/kotlin/cli/jvm/compiler/KotlinCoreEnvironment.kt

@@ -69,7 +69,6 @@ import org.jetbrains.kotlin.cli.common.messages.MessageCollector
 import org.jetbrains.kotlin.cli.common.toBooleanLenient
 import org.jetbrains.kotlin.cli.jvm.JvmRuntimeVersionsConsistencyChecker
 import org.jetbrains.kotlin.cli.jvm.compiler.jarfs.FastJarFileSystem
-import org.jetbrains.kotlin.cli.jvm.compiler.jarfs.FastJarHandler
 import org.jetbrains.kotlin.cli.jvm.config.*
 import org.jetbrains.kotlin.cli.jvm.index.*
 import org.jetbrains.kotlin.cli.jvm.javac.JavacWrapperRegistrar
@@ -171,9 +170,28 @@ class KotlinCoreEnvironment private constructor(
 
         val messageCollector = configuration.get(CLIConfigurationKeys.MESSAGE_COLLECTOR_KEY)
 
+        if (configuration.getBoolean(JVMConfigurationKeys.USE_FAST_JAR_FILE_SYSTEM)) {
+            messageCollector?.report(
+                STRONG_WARNING,
+                "Using new faster version of JAR FS: it should make your build faster, but the new implementation is experimental"
+            )
+        }
+
         jarFileSystem = when {
-            configuration.getBoolean(JVMConfigurationKeys.USE_FAST_JAR_FILE_SYSTEM) ||
-                    configuration.getBoolean(CommonConfigurationKeys.USE_FIR) -> FastJarFileSystem()
+            configuration.getBoolean(JVMConfigurationKeys.USE_FAST_JAR_FILE_SYSTEM) || configuration.getBoolean(CommonConfigurationKeys.USE_FIR) -> {
+                val fastJarFs = FastJarFileSystem.createIfUnmappingPossible()
+
+                if (fastJarFs == null) {
+                    messageCollector?.report(
+                        STRONG_WARNING,
+                        "Your JDK doesn't seem to support mapped buffer unmapping, so the slower (old) version of JAR FS will be used"
+                    )
+                    applicationEnvironment.jarFileSystem
+                } else {
+                    fastJarFs
+                }
+            }
+
             else -> applicationEnvironment.jarFileSystem
         }
 

compiler/cli/src/org/jetbrains/kotlin/cli/jvm/compiler/jarfs/FastJarFileSystem.kt

@@ -19,7 +19,7 @@ import java.nio.channels.FileChannel
 
 private typealias RandomAccessFileAndBuffer = Pair<RandomAccessFile, MappedByteBuffer>
 
-class FastJarFileSystem : DeprecatedVirtualFileSystem() {
+class FastJarFileSystem private constructor(internal val unmapBuffer: MappedByteBuffer.() -> Unit) : DeprecatedVirtualFileSystem() {
     private val myHandlers: MutableMap<String, FastJarHandler> =
         ConcurrentFactoryMap.createMap { key: String -> FastJarHandler(this@FastJarFileSystem, key) }
 
@@ -69,25 +69,27 @@ class FastJarFileSystem : DeprecatedVirtualFileSystem() {
             val pathInJar = path.substring(separator + 2)
             return Couple.of(localPath, pathInJar)
         }
+
+        fun createIfUnmappingPossible(): FastJarFileSystem? {
+            val cleanerCallBack = prepareCleanerCallback() ?: return null
+            return FastJarFileSystem(cleanerCallBack)
+        }
     }
 }
 
 
 private val IS_PRIOR_9_JRE = System.getProperty("java.specification.version", "").startsWith("1.")
 
-internal fun ByteBuffer.unmapBuffer() {
-    if (!isDirect) return
-
-    try {
+private fun prepareCleanerCallback(): ((ByteBuffer) -> Unit)? {
+    return try {
         if (IS_PRIOR_9_JRE) {
-            val cleaner = this::class.java.getMethod("cleaner")
-
+            val cleaner = Class.forName("java.nio.DirectByteBuffer").getMethod("cleaner")
             cleaner.isAccessible = true
 
             val clean = Class.forName("sun.misc.Cleaner").getMethod("clean")
             clean.isAccessible = true
 
-            clean.invoke(cleaner.invoke(this))
+            { buffer: ByteBuffer -> clean.invoke(cleaner.invoke(buffer)) }
         } else {
             val unsafeClass = try {
                 Class.forName("sun.misc.Unsafe")
@@ -103,10 +105,11 @@ internal fun ByteBuffer.unmapBuffer() {
             val theUnsafeField = unsafeClass.getDeclaredField("theUnsafe")
             theUnsafeField.isAccessible = true
 
-            val theUnsafe = theUnsafeField.get(null)
+            val theUnsafe = theUnsafeField.get(null);
 
-            clean.invoke(theUnsafe, this)
+            { buffer: ByteBuffer -> clean.invoke(theUnsafe, buffer) }
         }
     } catch (ex: Exception) {
+        null
     }
 }

compiler/cli/src/org/jetbrains/kotlin/cli/jvm/compiler/jarfs/FastJarHandler.kt

@@ -8,14 +8,10 @@ import com.intellij.openapi.util.text.StringUtil
 import com.intellij.openapi.vfs.VirtualFile
 import com.intellij.openapi.vfs.impl.ZipHandler
 import com.intellij.util.containers.FactoryMap
-import com.intellij.util.io.FileAccessorCache
 import com.intellij.util.text.ByteArrayCharSequence
-import java.io.File
 import java.io.FileNotFoundException
 import java.io.IOException
 import java.io.RandomAccessFile
-import java.nio.ByteBuffer
-import java.nio.MappedByteBuffer
 import java.nio.channels.FileChannel
 
 class FastJarHandler(val fileSystem: FastJarFileSystem, path: String) : ZipHandler(path) {
@@ -31,7 +27,9 @@ class FastJarHandler(val fileSystem: FastJarFileSystem, path: String) : ZipHandl
                 ourEntryMap = mappedByteBuffer.parseCentralDirectory().associateBy { it.relativePath }
                 cachedManifest = ourEntryMap[MANIFEST_PATH]?.let(mappedByteBuffer::contentsToByteArray)
             } finally {
-                mappedByteBuffer.unmapBuffer()
+                with(fileSystem) {
+                    mappedByteBuffer.unmapBuffer()
+                }
             }
         }