[PLAT-33341] Add Caffeine interface to limit Sjsonnet worker cache size

sjsonnet/src-js/sjsonnet/SjsonnetMain.scala

@@ -6,7 +6,7 @@ import scala.scalajs.js.annotation.{JSExport, JSExportTopLevel}
 
 @JSExportTopLevel("SjsonnetMain")
 object SjsonnetMain {
-  def createParseCache() = collection.mutable.HashMap[(Path, String), Either[String, (Expr, FileScope)]]()
+  def createParseCache() = new DefaultParseCache
   @JSExport
   def interpret(text: String,
                 extVars: js.Any,

sjsonnet/src-jvm-native/sjsonnet/SjsonnetMain.scala

@@ -7,8 +7,22 @@ import java.nio.file.NoSuchFileException
 import scala.util.Try
 import scala.util.control.NonFatal
 
+// Trait extended by JsonnetWorker (in universe) so that it can pass the cache based on Caffeine to main0 here
+trait ParseCache {
+  def getOrElseUpdate(key: (Path, String), defaultValue:  => Either[Error, (Expr, FileScope)]): Either[Error, (Expr, FileScope)]
+}
+
+// A default implementation based on a mutable HashMap. This implementation is not thread-safe.
+class DefaultParseCache extends ParseCache {
+  val cache = new collection.mutable.HashMap[(Path, String), Either[Error, (Expr, FileScope)]]()
+
+  override def getOrElseUpdate(key: (Path, String), defaultValue:  => Either[Error, (Expr, FileScope)]): Either[Error, (Expr, FileScope)] = {
+    cache.getOrElseUpdate(key, defaultValue)
+  }
+}
+
 object SjsonnetMain {
-  def createParseCache() = collection.mutable.HashMap[(Path, String), Either[Error, (Expr, FileScope)]]()
+  def createParseCache() = new DefaultParseCache
 
   def resolveImport(searchRoots0: Seq[Path], allowedInputs: Option[Set[os.Path]] = None) = new Importer {
     def resolve(docBase: Path, importName: String): Option[Path] =
@@ -33,7 +47,7 @@ object SjsonnetMain {
         case Array(s, _*) if s == "-i" || s == "--interactive" => args.tail
         case _ => args
       },
-      collection.mutable.HashMap.empty,
+      new DefaultParseCache,
       System.in,
       System.out,
       System.err,
@@ -44,7 +58,7 @@ object SjsonnetMain {
   }
 
   def main0(args: Array[String],
-            parseCache: collection.mutable.HashMap[(Path, String), Either[Error, (Expr, FileScope)]],
+            parseCache: ParseCache,
             stdin: InputStream,
             stdout: PrintStream,
             stderr: PrintStream,
@@ -127,7 +141,7 @@ object SjsonnetMain {
 
   def mainConfigured(file: String,
                      config: Config,
-                     parseCache: collection.mutable.HashMap[(Path, String), Either[Error, (Expr, FileScope)]],
+                     parseCache: ParseCache,
                      wd: os.Path,
                      allowedInputs: Option[Set[os.Path]] = None,
                      importer: Option[(Path, String) => Option[os.Path]] = None): Either[String, String] = {

sjsonnet/src/sjsonnet/Importer.scala

@@ -43,8 +43,8 @@ class CachedImporter(parent: Importer) extends Importer {
 
 class CachedResolver(
   parentImporter: Importer,
-  val parseCache: mutable.HashMap[(Path, String), Either[Error, (Expr, FileScope)]] = new mutable.HashMap
-) extends CachedImporter(parentImporter) {
+  val parseCache: ParseCache = new DefaultParseCache
+                    ) extends CachedImporter(parentImporter) {
 
   def parse(path: Path, txt: String)(implicit ev: EvalErrorScope): Either[Error, (Expr, FileScope)] = {
     parseCache.getOrElseUpdate((path, txt), {

sjsonnet/src/sjsonnet/Interpreter.scala

@@ -18,8 +18,8 @@ class Interpreter(extVars: Map[String, ujson.Value],
                   preserveOrder: Boolean = false,
                   strict: Boolean = false,
                   storePos: Position => Unit = null,
-                  val parseCache: mutable.HashMap[(Path, String), Either[Error, (Expr, FileScope)]] = new mutable.HashMap,
-                  ) { self =>
+                  val parseCache: ParseCache = new DefaultParseCache
+                 ) { self =>
 
   val resolver = new CachedResolver(importer, parseCache) {
     override def process(expr: Expr, fs: FileScope): Either[Error, (Expr, FileScope)] =

sjsonnet/test/src-jvm-native/sjsonnet/MainTests.scala

@@ -16,9 +16,9 @@ object MainTests extends TestSuite {
       val outF = File.createTempFile("sjsonnet", ".json")
       val out = new ByteArrayOutputStream()
       val pout = new PrintStream(out)
-      SjsonnetMain.main0(Array(source), collection.mutable.HashMap.empty, System.in, pout, System.err, os.pwd, None)
+      SjsonnetMain.main0(Array(source), new DefaultParseCache, System.in, pout, System.err, os.pwd, None)
       pout.flush()
-      SjsonnetMain.main0(Array("-o", outF.getAbsolutePath, source), collection.mutable.HashMap.empty, System.in, System.out, System.err, os.pwd, None)
+      SjsonnetMain.main0(Array("-o", outF.getAbsolutePath, source), new DefaultParseCache, System.in, System.out, System.err, os.pwd, None)
       val stdoutBytes = out.toByteArray
       val fileBytes = os.read(os.Path(outF)).getBytes
       // stdout mode uses println so it has an extra platform-specific line separator at the end