Add a task scheduler for background indexing and preparation

The scheduler isn’t actually being used yet but it’s complex and generic enough that it’s possible to review it by itself.

Package.swift

@@ -49,6 +49,12 @@ let package = Package(
       swiftSettings: [.enableExperimentalFeature("StrictConcurrency")]
     ),
 
+    // MARK: CAtomics
+    .target(
+      name: "CAtomics",
+      dependencies: []
+    ),
+
     // MARK: CSKTestSupport
     .target(
       name: "CSKTestSupport",
@@ -170,6 +176,7 @@ let package = Package(
       name: "SKCore",
       dependencies: [
         "BuildServerProtocol",
+        "CAtomics",
         "LanguageServerProtocol",
         "LanguageServerProtocolJSONRPC",
         "LSPLogging",

Sources/CAtomics/CMakeLists.txt

@@ -0,0 +1,2 @@
+add_library(CAtomics INTERFACE)
+target_include_directories(CAtomics INTERFACE "include")

Sources/CAtomics/include/CAtomics.h

@@ -0,0 +1,66 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2024 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SOURCEKITLSP_CATOMICS_H
+#define SOURCEKITLSP_CATOMICS_H
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <sys/types.h>
+
+// MARK: - AtomicBool
+
+typedef struct {
+  _Atomic(bool) value;
+} AtomicBool;
+
+__attribute__((swift_name("AtomicBool.init(initialValue:)")))
+static inline AtomicBool atomic_bool_create(bool initialValue) {
+  AtomicBool atomic;
+  atomic.value = initialValue;
+  return atomic;
+}
+
+__attribute__((swift_name("getter:AtomicBool.value(self:)")))
+static inline bool atomic_bool_get(AtomicBool *atomic) {
+  return atomic->value;
+}
+
+__attribute__((swift_name("setter:AtomicBool.value(self:_:)")))
+static inline void atomic_bool_set(AtomicBool *atomic, bool newValue) {
+  atomic->value = newValue;
+}
+
+// MARK: - AtomicUInt8
+
+typedef struct {
+  _Atomic(uint8_t) value;
+} AtomicUInt8;
+
+__attribute__((swift_name("AtomicUInt8.init(initialValue:)")))
+static inline AtomicUInt8 atomic_uint8_create(uint8_t initialValue) {
+  AtomicUInt8 atomic;
+  atomic.value = initialValue;
+  return atomic;
+}
+
+__attribute__((swift_name("getter:AtomicUInt8.value(self:)")))
+static inline uint8_t atomic_uint8_get(AtomicUInt8 *atomic) {
+  return atomic->value;
+}
+
+__attribute__((swift_name("setter:AtomicUInt8.value(self:_:)")))
+static inline void atomic_uint8_set(AtomicUInt8 *atomic, uint8_t newValue) {
+  atomic->value = newValue;
+}
+
+#endif // SOURCEKITLSP_CATOMICS_H

Sources/CAtomics/include/module.modulemap

@@ -0,0 +1,4 @@
+module CAtomics {
+  header "CAtomics.h"
+  export *
+}

Sources/CMakeLists.txt

@@ -1,4 +1,5 @@
 add_subdirectory(BuildServerProtocol)
+add_subdirectory(CAtomics)
 add_subdirectory(Csourcekitd)
 add_subdirectory(Diagnose)
 add_subdirectory(LanguageServerProtocol)

Sources/SKCore/CMakeLists.txt

@@ -13,13 +13,15 @@ add_library(SKCore STATIC
   MainFilesProvider.swift
   PathPrefixMapping.swift
   SplitShellCommand.swift
+  TaskScheduler.swift
   Toolchain.swift
   ToolchainRegistry.swift
   XCToolchainPlist.swift)
 set_target_properties(SKCore PROPERTIES
   INTERFACE_INCLUDE_DIRECTORIES ${CMAKE_Swift_MODULE_DIRECTORY})
 target_link_libraries(SKCore PUBLIC
   BuildServerProtocol
+  CAtomics
   LanguageServerProtocol
   LanguageServerProtocolJSONRPC
   LSPLogging