Implement quick non-script detection and lazy script discovery..

so ".kt" and ".java" files are not considered as scripts and quickly
filtered out, and for the other files the the checks are implemented
using sequences, mechanisms provided to supply script definitions
lazily, and script discovery is implemented using this mechanisms.

idea/idea-core/src/org/jetbrains/kotlin/idea/core/script/ScriptDefinitionsManager.kt

@@ -29,10 +29,7 @@ import com.intellij.openapi.vfs.VfsUtil
 import com.intellij.openapi.vfs.VirtualFile
 import org.jetbrains.kotlin.idea.caches.project.SdkInfo
 import org.jetbrains.kotlin.idea.caches.project.getScriptRelatedModuleInfo
-import org.jetbrains.kotlin.script.KotlinScriptDefinition
-import org.jetbrains.kotlin.script.KotlinScriptDefinitionFromAnnotatedTemplate
-import org.jetbrains.kotlin.script.ScriptDefinitionProvider
-import org.jetbrains.kotlin.script.ScriptTemplatesProvider
+import org.jetbrains.kotlin.script.*
 import org.jetbrains.kotlin.scripting.compiler.plugin.KotlinScriptDefinitionAdapterFromNewAPI
 import org.jetbrains.kotlin.utils.PathUtil
 import org.jetbrains.kotlin.utils.addToStdlib.firstIsInstanceOrNull
@@ -40,8 +37,6 @@ import org.jetbrains.kotlin.utils.addToStdlib.flattenTo
 import java.io.File
 import java.lang.reflect.InvocationTargetException
 import java.net.URLClassLoader
-import java.util.concurrent.locks.ReentrantReadWriteLock
-import kotlin.concurrent.read
 import kotlin.concurrent.write
 import kotlin.script.dependencies.Environment
 import kotlin.script.dependencies.ScriptContents
@@ -53,14 +48,12 @@ import kotlin.script.experimental.dependencies.ScriptDependencies
 import kotlin.script.experimental.dependencies.asSuccess
 import kotlin.script.templates.standard.ScriptTemplateWithArgs
 
-class ScriptDefinitionsManager(private val project: Project) : ScriptDefinitionProvider {
-    private val lock = ReentrantReadWriteLock()
+class ScriptDefinitionsManager(private val project: Project) : LazyScriptDefinitionProvider() {
     private var definitionsByContributor = mutableMapOf<ScriptDefinitionContributor, List<KotlinScriptDefinition>>()
-    private var definitions: List<KotlinScriptDefinition> = emptyList()
+    private var definitions: Sequence<KotlinScriptDefinition>? = null
 
     fun reloadDefinitionsBy(contributor: ScriptDefinitionContributor) = lock.write {
-        val notLoadedYet = definitions.isEmpty()
-        if (notLoadedYet) return
+        if (definitions == null) return // not loaded yet
 
         if (contributor !in definitionsByContributor) error("Unknown contributor: ${contributor.id}")
 
@@ -70,32 +63,19 @@ class ScriptDefinitionsManager(private val project: Project) : ScriptDefinitionP
     }
 
     fun getDefinitionsBy(contributor: ScriptDefinitionContributor): List<KotlinScriptDefinition> = lock.write {
-        val notLoadedYet = definitions.isEmpty()
-        if (notLoadedYet) return emptyList()
+        if (definitions == null) return emptyList() // not loaded yet
 
         if (contributor !in definitionsByContributor) error("Unknown contributor: ${contributor.id}")
 
         return definitionsByContributor[contributor] ?: emptyList()
     }
 
-    private fun currentDefinitions(): List<KotlinScriptDefinition> {
-        val hasDefinitions = definitions.isNotEmpty()
-        when {
-            hasDefinitions -> return definitions
-            else -> {
+    override val currentDefinitions: Sequence<KotlinScriptDefinition>
+        get() =
+            definitions ?: kotlin.run {
                 reloadScriptDefinitions()
-                return definitions
+                definitions!!
             }
-        }
-    }
-
-    override fun findScriptDefinition(fileName: String): KotlinScriptDefinition? = lock.read {
-        currentDefinitions().firstOrNull { it.isScript(fileName) }
-    }
-
-    override fun isScript(fileName: String) = lock.read {
-        currentDefinitions().any { it.isScript(fileName) }
-    }
 
     private fun getContributors(): List<ScriptDefinitionContributor> {
         @Suppress("DEPRECATION")
@@ -115,7 +95,8 @@ class ScriptDefinitionsManager(private val project: Project) : ScriptDefinitionP
     }
 
     private fun updateDefinitions() {
-        definitions = definitionsByContributor.values.flattenTo(mutableListOf())
+        definitions = definitionsByContributor.values.flattenTo(mutableListOf()).asSequence()
+        clearCache()
         // TODO: clear by script type/definition
         ServiceManager.getService(project, ScriptDependenciesUpdater::class.java).clear()
     }

idea/idea-core/src/org/jetbrains/kotlin/idea/core/script/ScriptDependenciesManager.kt

@@ -25,6 +25,7 @@ import com.intellij.util.io.URLUtil
 import org.jetbrains.annotations.TestOnly
 import org.jetbrains.kotlin.script.ScriptDefinitionProvider
 import org.jetbrains.kotlin.script.ScriptDependenciesProvider
+import org.jetbrains.kotlin.script.findScriptDefinition
 import java.io.File
 import kotlin.script.experimental.dependencies.ScriptDependencies