From 2add119d9f50b60f45c1ec5a34a80c9b6babc09a Mon Sep 17 00:00:00 2001
From: Tomasz Godzik <tomek.godzik@gmail.com>
Date: Mon, 14 Oct 2019 17:22:47 +0200
Subject: [PATCH] Make find implementation run on a separate thread for each
 file

---
 .../ImplementationProvider.scala              | 52 ++++++++++++-------
 1 file changed, 32 insertions(+), 20 deletions(-)

diff --git a/metals/src/main/scala/scala/meta/internal/implementation/ImplementationProvider.scala b/metals/src/main/scala/scala/meta/internal/implementation/ImplementationProvider.scala
index 22b439b32b8..18b298cb25f 100644
--- a/metals/src/main/scala/scala/meta/internal/implementation/ImplementationProvider.scala
+++ b/metals/src/main/scala/scala/meta/internal/implementation/ImplementationProvider.scala
@@ -27,6 +27,8 @@ import scala.collection.mutable
 import scala.meta.internal.symtab.GlobalSymbolTable
 import scala.util.control.NonFatal
 import scala.meta.internal.mtags.Mtags
+import scala.concurrent.ExecutionContext
+import java.util.concurrent.ConcurrentLinkedQueue
 
 final class ImplementationProvider(
     semanticdbs: Semanticdbs,
@@ -35,7 +37,7 @@ final class ImplementationProvider(
     buildTargets: BuildTargets,
     buffer: Buffers,
     definitionProvider: DefinitionProvider
-) {
+)(implicit ec: ExecutionContext) {
   import ImplementationProvider._
 
   private val globalTable = new GlobalClassTable(buildTargets)
@@ -81,7 +83,9 @@ final class ImplementationProvider(
     }
   }
 
-  def implementations(params: TextDocumentPositionParams): List[Location] = {
+  def implementations(
+      params: TextDocumentPositionParams
+  ): List[Location] = {
     val source = params.getTextDocument.getUri.toAbsolutePath
     lazy val global = globalTable.globalSymbolTableFor(source)
     val locations = for {
@@ -177,29 +181,37 @@ final class ImplementationProvider(
     }
 
     import TokenEditDistance.fromBuffer
-
+    val allLocations = new ConcurrentLinkedQueue[Location]
     for {
       classContext <- inheritanceContext.toIterable
       plainParentSymbol <- classContext.findSymbol(symbol).toIterable
       parentSymbol = addParameterSignatures(plainParentSymbol, classContext)
       symbolClass <- classFromSymbol(parentSymbol, classContext.findSymbol)
-      (file, locations) <- findImplementation(symbolClass.symbol, classContext)
-      implPath = AbsolutePath(file)
-      implDocument <- findSemanticdb(implPath).toIterable
-      distance = fromBuffer(implPath, implDocument.text, buffer)
-      implLocation <- locations
-      implReal = implLocation.toRealNames(symbolClass, translateKey = true)
-      implSymbol <- findImplementationSymbol(
-        parentSymbol,
-        implDocument,
-        symbolClass,
-        classContext,
-        implReal
-      )
-      implOccurrence <- findDefOccurrence(implDocument, implSymbol, source)
-      range <- implOccurrence.range
-      revised <- distance.toRevised(range.toLSP)
-    } yield new Location(file.toUri.toString, revised)
+      parallelMap = findImplementation(
+        symbolClass.symbol,
+        classContext
+      ).par
+    } parallelMap.foreach {
+      case (file, locations) =>
+        val implPath = AbsolutePath(file)
+        for {
+          implDocument <- findSemanticdb(implPath).toIterable
+          distance = fromBuffer(implPath, implDocument.text, buffer)
+          implLocation <- locations
+          implReal = implLocation.toRealNames(symbolClass, translateKey = true)
+          implSymbol <- findImplementationSymbol(
+            parentSymbol,
+            implDocument,
+            symbolClass,
+            classContext,
+            implReal
+          )
+          implOccurence <- findDefOccurrence(implDocument, implSymbol, source)
+          range <- implOccurence.range
+          revised <- distance.toRevised(range.toLSP)
+        } allLocations.add(new Location(file.toUri.toString, revised))
+    }
+    allLocations.asScala
   }
 
   private def findSemanticdb(fileSource: AbsolutePath): Option[TextDocument] =