Allow alternate build systems to have larger indexing batch sizes

Author: rockbruno

Sources/BuildServerIntegration/BuildServerManager.swift

@@ -316,13 +316,17 @@ package actor BuildServerManager: QueueBasedMessageHandler {
   /// `nil` if the `BuildServerManager` does not have an underlying build server.
   package let configPath: URL?
 
+  /// The kind of underlying build server adapter that is being managed.
+  /// `nil` if the `BuildServerManager` does not have an underlying build server.
+  package var kind: BuildServerSpec.Kind?
+
   /// The files for which the delegate has requested change notifications, ie. the files for which the delegate wants to
   /// get `fileBuildSettingsChanged` and `filesDependenciesUpdated` callbacks.
   private var watchedFiles: [DocumentURI: (mainFile: DocumentURI, language: Language)] = [:]
 
   private var connectionToClient: BuildServerManagerConnectionToClient
 
-  /// The build serer adapter that is used to answer build server queries.
+  /// The build server adapter that is used to answer build server queries.
   private var buildServerAdapter: BuildServerAdapter?
 
   /// The build server adapter after initialization finishes. When sending messages to the BSP server, this should be
@@ -451,6 +455,7 @@ package actor BuildServerManager: QueueBasedMessageHandler {
     self.toolchainRegistry = toolchainRegistry
     self.options = options
     self.connectionToClient = connectionToClient
+    self.kind = buildServerSpec?.kind
     self.configPath = buildServerSpec?.configPath
     self.buildServerAdapter = await buildServerSpec?.createBuildServerAdapter(
       toolchainRegistry: toolchainRegistry,

Sources/SemanticIndex/SemanticIndexManager.swift

@@ -222,6 +222,9 @@ package final actor SemanticIndexManager {
   /// The parameter is the number of files that were scheduled to be indexed.
   private let indexTasksWereScheduled: @Sendable (_ numberOfFileScheduled: Int) -> Void
 
+  /// The number of tasks to prepare concurrently, whenever a index request is scheduled.
+  private let indexTaskBatchSize: Int
+
   /// Callback that is called when `progressStatus` might have changed.
   private let indexProgressStatusDidChange: @Sendable () -> Void
 
@@ -261,6 +264,7 @@ package final actor SemanticIndexManager {
     updateIndexStoreTimeout: Duration,
     hooks: IndexHooks,
     indexTaskScheduler: TaskScheduler<AnyIndexTaskDescription>,
+    indexTaskBatchSize: Int,
     logMessageToIndexLog:
       @escaping @Sendable (
         _ message: String, _ type: WindowMessageType, _ structure: StructuredLogKind
@@ -273,6 +277,7 @@ package final actor SemanticIndexManager {
     self.updateIndexStoreTimeout = updateIndexStoreTimeout
     self.hooks = hooks
     self.indexTaskScheduler = indexTaskScheduler
+    self.indexTaskBatchSize = indexTaskBatchSize
     self.logMessageToIndexLog = logMessageToIndexLog
     self.indexTasksWereScheduled = indexTasksWereScheduled
     self.indexProgressStatusDidChange = indexProgressStatusDidChange
@@ -877,10 +882,7 @@ package final actor SemanticIndexManager {
 
     var indexTasks: [Task<Void, Never>] = []
 
-    // TODO: When we can index multiple targets concurrently in SwiftPM, increase the batch size to half the
-    // processor count, so we can get parallelism during preparation.
-    // (https://github.com/swiftlang/sourcekit-lsp/issues/1262)
-    for targetsBatch in sortedTargets.partition(intoBatchesOfSize: 1) {
+    for targetsBatch in sortedTargets.partition(intoBatchesOfSize: indexTaskBatchSize) {
       let preparationTaskID = UUID()
       let filesToIndex = targetsBatch.flatMap({ filesByTarget[$0]! })
 

Sources/SourceKitLSP/Workspace.swift

@@ -162,12 +162,23 @@ package final class Workspace: Sendable, BuildServerManagerDelegate {
     if options.backgroundIndexingOrDefault, let uncheckedIndex,
       await buildServerManager.initializationData?.prepareProvider ?? false
     {
+      let batchSize: Int
+      switch await buildServerManager.kind {
+      case .swiftPM:
+        // TODO: When we can index multiple targets concurrently in SwiftPM, increase the batch size to half the
+        // processor count, so we can get parallelism during preparation.
+        // (https://github.com/swiftlang/sourcekit-lsp/issues/1262)
+        batchSize = 1
+      default:
+        batchSize = max(1, ProcessInfo.processInfo.activeProcessorCount / 2)
+      }
       self.semanticIndexManager = SemanticIndexManager(
         index: uncheckedIndex,
         buildServerManager: buildServerManager,
         updateIndexStoreTimeout: options.indexOrDefault.updateIndexStoreTimeoutOrDefault,
         hooks: hooks.indexHooks,
         indexTaskScheduler: indexTaskScheduler,
+        indexTaskBatchSize: batchSize,
         logMessageToIndexLog: { [weak sourceKitLSPServer] in
           sourceKitLSPServer?.logMessageToIndexLog(message: $0, type: $1, structure: $2)
         },