Optimize Strings representation at FastJarHandler

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

@@ -0,0 +1,40 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+package org.jetbrains.kotlin.cli.jvm.compiler.jarfs
+
+class ByteArrayCharSequence(
+    private val bytes: ByteArray,
+    private val start: Int = 0,
+    private val end: Int = bytes.size
+) : CharSequence {
+
+    override fun hashCode(): Int {
+        error("Do not try computing hashCode ByteArrayCharSequence")
+    }
+
+    override fun equals(other: Any?): Boolean {
+        error("Do not try comparing ByteArrayCharSequence")
+    }
+
+    override val length get() = end - start
+
+    override fun get(index: Int): Char = bytes[index + start].toChar()
+
+    override fun subSequence(startIndex: Int, endIndex: Int): CharSequence {
+        if (startIndex == 0 && endIndex == length) return this
+        return ByteArrayCharSequence(bytes, start + startIndex, start + endIndex)
+    }
+
+    override fun toString(): String {
+        val chars = CharArray(length)
+
+        for (i in 0 until length) {
+            chars[i] = bytes[i + start].toChar()
+        }
+
+        return String(chars)
+    }
+}
+

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

@@ -4,6 +4,7 @@
  */
 package org.jetbrains.kotlin.cli.jvm.compiler.jarfs
 
+import com.intellij.openapi.util.text.StringUtil
 import com.intellij.openapi.vfs.VirtualFile
 import java.io.File
 import java.io.FileNotFoundException
@@ -22,7 +23,9 @@ class FastJarHandler(val fileSystem: FastJarFileSystem, path: String) {
             val mappedByteBuffer = randomAccessFile.channel.map(FileChannel.MapMode.READ_ONLY, 0, randomAccessFile.length())
             try {
                 entries = mappedByteBuffer.parseCentralDirectory()
-                cachedManifest = entries.singleOrNull { it.relativePath == MANIFEST_PATH }?.let(mappedByteBuffer::contentsToByteArray)
+                cachedManifest =
+                    entries.singleOrNull { StringUtil.equals(MANIFEST_PATH, it.relativePath) }
+                        ?.let(mappedByteBuffer::contentsToByteArray)
             } finally {
                 with(fileSystem) {
                     mappedByteBuffer.unmapBuffer()
@@ -66,8 +69,8 @@ class FastJarHandler(val fileSystem: FastJarFileSystem, path: String) {
         )
     }
 
-    private fun getOrCreateDirectory(entryName: String, directories: MutableMap<String, FastJarVirtualFile>): FastJarVirtualFile {
-        return directories.getOrPut(entryName) {
+    private fun getOrCreateDirectory(entryName: CharSequence, directories: MutableMap<String, FastJarVirtualFile>): FastJarVirtualFile {
+        return directories.getOrPut(entryName.toString()) {
             val (parentPath, shortName) = entryName.splitPath()
             val parentFile = getOrCreateDirectory(parentPath, directories)
 
@@ -75,7 +78,7 @@ class FastJarHandler(val fileSystem: FastJarFileSystem, path: String) {
         }
     }
 
-    private fun String.splitPath(): Pair<String, String> {
+    private fun CharSequence.splitPath(): Pair<CharSequence, CharSequence> {
         var slashIndex = this.length - 1
 
         while (slashIndex >= 0 && this[slashIndex] != '/') {
@@ -83,7 +86,7 @@ class FastJarHandler(val fileSystem: FastJarFileSystem, path: String) {
         }
 
         if (slashIndex == -1) return Pair("", this)
-        return Pair(substring(0, slashIndex), substring(slashIndex + 1))
+        return Pair(subSequence(0, slashIndex), subSequence(slashIndex + 1, this.length))
     }
 
     fun findFileByPath(pathInJar: String): VirtualFile? {
@@ -92,7 +95,7 @@ class FastJarHandler(val fileSystem: FastJarFileSystem, path: String) {
 
     fun contentsToByteArray(zipEntryDescription: ZipEntryDescription): ByteArray {
         val relativePath = zipEntryDescription.relativePath
-        if (relativePath == MANIFEST_PATH) return cachedManifest ?: throw FileNotFoundException("$file!/$relativePath")
+        if (StringUtil.equals(relativePath, MANIFEST_PATH)) return cachedManifest ?: throw FileNotFoundException("$file!/$relativePath")
         return fileSystem.cachedOpenFileHandles[file].use {
             synchronized(it) {
                 it.get().second.contentsToByteArray(zipEntryDescription)

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

@@ -12,12 +12,12 @@ import java.util.zip.Inflater
 
 
 class ZipEntryDescription(
-    val relativePath: String,
+    val relativePath: CharSequence,
     val compressedSize: Int,
     val uncompressedSize: Int,
     val offsetInFile: Int,
     val compressionKind: CompressionKind,
-    val fileNameSize: Int
+    val fileNameSize: Int,
 ) {
 
     enum class CompressionKind {
@@ -101,7 +101,7 @@ fun MappedByteBuffer.parseCentralDirectory(): List<ZipEntryDescription> {
 
         val name =
             if (bytesForName.all { it >= 0 })
-                String(bytesForName.asASCICharArray())
+                ByteArrayCharSequence(bytesForName)
             else
                 String(bytesForName, Charsets.UTF_8)
 
@@ -126,6 +126,4 @@ fun MappedByteBuffer.parseCentralDirectory(): List<ZipEntryDescription> {
     return result
 }
 
-private fun ByteArray.asASCICharArray(): CharArray = CharArray(size) { this@asASCICharArray[it].toChar() }
-
 private fun ByteBuffer.getUnsignedShort(offset: Int): Int = java.lang.Short.toUnsignedInt(getShort(offset))