[K/N] Worker API improvements ^KT-52429

Merge-request: KT-MR-6898
Merged-by: Alexander Shabalin <Alexander.Shabalin@jetbrains.com>

kotlin-native/runtime/src/main/cpp/Worker.cpp

@@ -30,6 +30,7 @@
 #include "Exceptions.h"
 #include "KAssert.h"
 #include "Memory.h"
+#include "Natives.h"
 #include "ObjCMMAPI.h"
 #include "Runtime.h"
 #include "Types.h"
@@ -632,6 +633,33 @@ class State {
     }
   }
 
+  KULong getWorkerPlatformThreadIdUnlocked(KInt id) {
+      Locker locker(&lock_);
+      auto it = workers_.find(id);
+      if (it == workers_.end()) {
+          ThrowWorkerAlreadyTerminated();
+      }
+      pthread_t thread = it->second->thread();
+      static_assert(sizeof(pthread_t) <= sizeof(KULong), "Casting pthread_t to ULong will lose data");
+      return reinterpret_cast<KULong>(thread);
+  }
+
+  OBJ_GETTER0(getActiveWorkers) {
+      std_support::vector<KInt> workers;
+      {
+          Locker locker(&lock_);
+
+          workers.reserve(workers_.size());
+          for (auto [id, worker] : workers_) {
+              workers.push_back(id);
+          }
+      }
+      ObjHolder arrayHolder;
+      AllocArrayInstance(theIntArrayTypeInfo, workers.size(), arrayHolder.slot());
+      std::copy(workers.begin(), workers.end(), IntArrayAddressOfElementAt(arrayHolder.obj()->array(), 0));
+      RETURN_OBJ(arrayHolder.obj());
+  }
+
  private:
   pthread_mutex_t lock_;
   pthread_cond_t cond_;
@@ -764,6 +792,14 @@ KNativePtr detachObjectGraphInternal(KInt transferMode, KRef producer) {
    }
 }
 
+KULong platformThreadId(KInt id) {
+    return theState()->getWorkerPlatformThreadIdUnlocked(id);
+}
+
+OBJ_GETTER0(activeWorkers) {
+    RETURN_RESULT_OF0(theState()->getActiveWorkers);
+}
+
 #else
 
 KInt startWorker(WorkerExceptionHandling exceptionHandling, KRef customName) {
@@ -822,6 +858,14 @@ KNativePtr detachObjectGraphInternal(KInt transferMode, KRef producer) {
   ThrowWorkerUnsupported();
 }
 
+KULong platformThreadId(KInt id) {
+    ThrowWorkerUnsupported();
+}
+
+OBJ_GETTER0(activeWorkers) {
+    ThrowWorkerUnsupported();
+}
+
 #endif  // WITH_WORKERS
 
 }  // namespace
@@ -1224,4 +1268,12 @@ void Kotlin_Worker_waitTermination(KInt id) {
     WaitNativeWorkerTermination(id);
 }
 
+KULong Kotlin_Worker_getPlatformThreadIdInternal(KInt id) {
+    return platformThreadId(id);
+}
+
+OBJ_GETTER0(Kotlin_Worker_getActiveWorkersInternal) {
+    RETURN_RESULT_OF0(activeWorkers);
+}
+
 }  // extern "C"

kotlin-native/runtime/src/main/kotlin/kotlin/native/concurrent/Internal.kt

@@ -128,3 +128,9 @@ external internal fun checkIfFrozen(ref: Any?)
 @InternalForKotlinNative
 @GCUnsafeCall("Kotlin_Worker_waitTermination")
 external public fun waitWorkerTermination(worker: Worker)
+
+@GCUnsafeCall("Kotlin_Worker_getPlatformThreadIdInternal")
+external internal fun getPlatfromThreadIdInternal(id: Int): ULong
+
+@GCUnsafeCall("Kotlin_Worker_getActiveWorkersInternal")
+external internal fun getActiveWorkersInternal(): IntArray

kotlin-native/runtime/src/main/kotlin/kotlin/native/concurrent/Worker.kt

@@ -60,6 +60,16 @@ public value class Worker @PublishedApi internal constructor(val id: Int) {
         @Deprecated("Use kotlinx.cinterop.StableRef instead", level = DeprecationLevel.WARNING)
         public fun fromCPointer(pointer: COpaquePointer?): Worker =
                 if (pointer != null) Worker(pointer.toLong().toInt()) else throw IllegalArgumentException()
+
+        /**
+         * Get a list of all unterminated workers.
+         *
+         * Thread safety: If some other thread calls [Worker.requestTermination] at the same time then this may
+         * return a [Worker] that's already terminated.
+         */
+        @ExperimentalStdlibApi
+        public val activeWorkers: List<Worker>
+            get() = getActiveWorkersInternal().map { Worker(it) }
     }
 
     /**
@@ -170,6 +180,15 @@ public value class Worker @PublishedApi internal constructor(val id: Int) {
      */
     @Deprecated("Use kotlinx.cinterop.StableRef instead", level = DeprecationLevel.WARNING)
     public fun asCPointer() : COpaquePointer? = id.toLong().toCPointer()
+
+    /**
+     * Get platform thread id of the worker thread.
+     *
+     * Usually returns `pthread_t` casted to [ULong].
+     */
+    @ExperimentalStdlibApi
+    public val platformThreadId: ULong
+        get() = getPlatfromThreadIdInternal(id)
 }
 
 /**