Avoid another case of reading file content when building stubs

Do not read file content in isKotlinInternalCompiledFile() if possible

idea/idea-analysis/src/org/jetbrains/kotlin/idea/caches/IDEKotlinBinaryClassCache.kt

@@ -32,7 +32,7 @@ object IDEKotlinBinaryClassCache {
     /**
      * Checks if this file is a compiled Kotlin class file (not necessarily ABI-compatible with the current plugin)
      */
-    fun isKotlinJvmCompiledFile(file: VirtualFile): Boolean {
+    fun isKotlinJvmCompiledFile(file: VirtualFile, fileContent: ByteArray? = null): Boolean {
         if (file.extension != JavaClassFileType.INSTANCE!!.defaultExtension) {
             return false
         }
@@ -41,7 +41,7 @@ object IDEKotlinBinaryClassCache {
         if (cached != null) {
             return cached.isKotlinBinary
         }
-        return getKotlinBinaryClass(file) != null
+        return getKotlinBinaryClass(file, fileContent) != null
     }
 
     fun getKotlinBinaryClass(file: VirtualFile, fileContent: ByteArray? = null): KotlinJvmBinaryClass? {

idea/idea-analysis/src/org/jetbrains/kotlin/idea/decompiler/classFile/ClassFileDecompilerUtil.kt

@@ -49,16 +49,17 @@ fun isKotlinWithCompatibleAbiVersion(file: VirtualFile): Boolean {
  * Checks if this file is a compiled "internal" Kotlin class, i.e. a Kotlin class (not necessarily ABI-compatible with the current plugin)
  * which should NOT be decompiled (and, as a result, shown under the library in the Project view, be searchable via Find class, etc.)
  */
-fun isKotlinInternalCompiledFile(file: VirtualFile): Boolean {
-    if (!IDEKotlinBinaryClassCache.isKotlinJvmCompiledFile(file)) {
+fun isKotlinInternalCompiledFile(file: VirtualFile, fileContent: ByteArray): Boolean {
+    if (!IDEKotlinBinaryClassCache.isKotlinJvmCompiledFile(file, fileContent)) {
         return false
     }
 
-    if (ClassFileViewProvider.isInnerClass(file)) {
+    val innerClass = ClassFileViewProvider.isInnerClass(file, fileContent)
+    if (innerClass) {
         return true
     }
 
-    val (header, classId) = IDEKotlinBinaryClassCache.getKotlinBinaryClassHeaderData(file) ?: return false
+    val (header, classId) = IDEKotlinBinaryClassCache.getKotlinBinaryClassHeaderData(file, fileContent) ?: return false
     if (classId.isLocal) return true
 
     return header.kind == KotlinClassHeader.Kind.SYNTHETIC_CLASS ||

idea/idea-analysis/src/org/jetbrains/kotlin/idea/decompiler/classFile/KotlinClassFileDecompiler.kt

@@ -37,6 +37,7 @@ import org.jetbrains.kotlin.load.kotlin.header.KotlinClassHeader
 import org.jetbrains.kotlin.renderer.DescriptorRenderer
 import org.jetbrains.kotlin.types.asFlexibleType
 import org.jetbrains.kotlin.types.isFlexible
+import java.io.IOException
 
 class KotlinClassFileDecompiler : ClassFileDecompilers.Full() {
     private val stubBuilder = KotlinClsStubBuilder()
@@ -47,14 +48,21 @@ class KotlinClassFileDecompiler : ClassFileDecompilers.Full() {
 
     override fun createFileViewProvider(file: VirtualFile, manager: PsiManager, physical: Boolean): KotlinDecompiledFileViewProvider {
         val project = manager.project
-        return KotlinDecompiledFileViewProvider(manager, file, physical) { provider ->
+        return KotlinDecompiledFileViewProvider(manager, file, physical) factory@{ provider ->
             val virtualFile = provider.virtualFile
             val fileIndex = ServiceManager.getService(project, FileIndexFacade::class.java)
-            when {
-                !fileIndex.isInLibraryClasses(virtualFile) && fileIndex.isInSource(virtualFile) -> null
-                isKotlinInternalCompiledFile(virtualFile) -> null
-                else -> KtClsFile(provider)
+            if (!fileIndex.isInLibraryClasses(virtualFile) && fileIndex.isInSource(virtualFile)) return@factory null
+            val content = try {
+                virtualFile.contentsToByteArray(false)
             }
+            catch (e: IOException) {
+                return@factory null
+            }
+
+            if (isKotlinInternalCompiledFile(virtualFile, content))
+                null
+            else
+                KtClsFile(provider)
         }
     }
 }

idea/idea-analysis/src/org/jetbrains/kotlin/idea/decompiler/classFile/KotlinClsStubBuilder.kt

@@ -44,7 +44,7 @@ open class KotlinClsStubBuilder : ClsStubBuilder() {
     override fun buildFileStub(content: FileContent): PsiFileStub<*>? {
         val file = content.file
 
-        if (isKotlinInternalCompiledFile(file)) {
+        if (isKotlinInternalCompiledFile(file, content.content)) {
             return null
         }