SERVER-49548 Convert ServiceExecutor to use unique_function

6 files changed, 18 insertions, 15 deletions

diff --git a/src/mongo/transport/service_entry_point_utils.cpp b/src/mongo/transport/service_entry_point_utils.cpp
index f9489149ddf..f0c95a28dba 100644
--- a/src/mongo/transport/service_entry_point_utils.cpp
+++ b/src/mongo/transport/service_entry_point_utils.cpp
@@ -57,18 +57,19 @@ namespace mongo {
 
 namespace {
 void* runFunc(void* ctx) {
-    std::unique_ptr<std::function<void()>> taskPtr(static_cast<std::function<void()>*>(ctx));
+    auto taskPtr =
+        std::unique_ptr<unique_function<void()>>(static_cast<unique_function<void()>*>(ctx));
     (*taskPtr)();
 
     return nullptr;
 }
 }  // namespace
 
-Status launchServiceWorkerThread(std::function<void()> task) noexcept {
+Status launchServiceWorkerThread(unique_function<void()> task) noexcept {
 
     try {
 #if defined(_WIN32)
-        stdx::thread(std::move(task)).detach();
+        stdx::thread([task = std::move(task)]() mutable { task(); }).detach();
 #else
         pthread_attr_t attrs;
         pthread_attr_init(&attrs);
@@ -102,13 +103,13 @@ Status launchServiceWorkerThread(std::function<void()> task) noexcept {
 
         // Wrap the user-specified `task` so it runs with an installed `sigaltstack`.
         task = [sigAltStackController = std::make_shared<stdx::support::SigAltStackController>(),
-                f = std::move(task)] {
+                f = std::move(task)]() mutable {
             auto sigAltStackGuard = sigAltStackController->makeInstallGuard();
             f();
         };
 
         pthread_t thread;
-        auto ctx = std::make_unique<std::function<void()>>(std::move(task));
+        auto ctx = std::make_unique<unique_function<void()>>(std::move(task));
         ThreadSafetyContext::getThreadSafetyContext()->onThreadCreate();
         int failed = pthread_create(&thread, &attrs, runFunc, ctx.get());
 
diff --git a/src/mongo/transport/service_entry_point_utils.h b/src/mongo/transport/service_entry_point_utils.h
index c63afc5027b..f6f83d6d37e 100644
--- a/src/mongo/transport/service_entry_point_utils.h
+++ b/src/mongo/transport/service_entry_point_utils.h
@@ -32,9 +32,10 @@
 #include <functional>
 
 #include "mongo/transport/session.h"
+#include "mongo/util/functional.h"
 
 namespace mongo {
 
-Status launchServiceWorkerThread(std::function<void()> task) noexcept;
+Status launchServiceWorkerThread(unique_function<void()> task) noexcept;
 
 }  // namespace mongo
diff --git a/src/mongo/transport/service_executor.h b/src/mongo/transport/service_executor.h
index 6a1410ae86b..d44bb704c66 100644
--- a/src/mongo/transport/service_executor.h
+++ b/src/mongo/transport/service_executor.h
@@ -36,6 +36,7 @@
 #include "mongo/platform/bitwise_enum_operators.h"
 #include "mongo/transport/transport_mode.h"
 #include "mongo/util/duration.h"
+#include "mongo/util/functional.h"
 
 namespace mongo {
 // This needs to be forward declared here because the service_context.h is a circular dependency.
@@ -49,7 +50,7 @@ namespace transport {
 class ServiceExecutor {
 public:
     virtual ~ServiceExecutor() = default;
-    using Task = std::function<void()>;
+    using Task = unique_function<void()>;
     enum ScheduleFlags {
         // No flags (kEmptyFlags) specifies that this is a normal task and that the executor should
         // launch new threads as needed to run the task.
diff --git a/src/mongo/transport/service_executor_fixed.cpp b/src/mongo/transport/service_executor_fixed.cpp
index 48a94cd57cd..ba8eca2bfaf 100644
--- a/src/mongo/transport/service_executor_fixed.cpp
+++ b/src/mongo/transport/service_executor_fixed.cpp
@@ -128,7 +128,7 @@ Status ServiceExecutorFixed::schedule(Task task, ScheduleFlags flags) {
         if (_executorContext->getRecursionDepth() <
             fixedServiceExecutorRecursionLimit.loadRelaxed()) {
             // Recursively executing the task on the executor thread.
-            _executorContext->run(task);
+            _executorContext->run(std::move(task));
             return Status::OK();
         }
     }
@@ -137,10 +137,10 @@ Status ServiceExecutorFixed::schedule(Task task, ScheduleFlags flags) {
 
     // May throw if an attempt is made to schedule after the thread pool is shutdown.
     try {
-        _threadPool->schedule([task = std::move(task)](Status status) {
+        _threadPool->schedule([task = std::move(task)](Status status) mutable {
             internalAssert(status);
             invariant(_executorContext);
-            _executorContext->run(task);
+            _executorContext->run(std::move(task));
         });
     } catch (DBException& e) {
         return e.toStatus();
diff --git a/src/mongo/transport/service_executor_synchronous.cpp b/src/mongo/transport/service_executor_synchronous.cpp
index 15724d3470c..10cc0ad3cce 100644
--- a/src/mongo/transport/service_executor_synchronous.cpp
+++ b/src/mongo/transport/service_executor_synchronous.cpp
@@ -114,7 +114,7 @@ Status ServiceExecutorSynchronous::schedule(Task task, ScheduleFlags flags) {
     LOGV2_DEBUG(22983, 3, "Starting new executor thread in passthrough mode");
 
     Status status = launchServiceWorkerThread(
-        [this, condVarAnchor = _shutdownCondition, task = std::move(task)] {
+        [this, condVarAnchor = _shutdownCondition, task = std::move(task)]() mutable {
             _numRunningWorkerThreads.addAndFetch(1);
 
             _localWorkQueue.emplace_back(std::move(task));
diff --git a/src/mongo/transport/service_executor_test.cpp b/src/mongo/transport/service_executor_test.cpp
index 99ee7f3ddb5..f79597a5521 100644
--- a/src/mongo/transport/service_executor_test.cpp
+++ b/src/mongo/transport/service_executor_test.cpp
@@ -233,8 +233,8 @@ TEST_F(ServiceExecutorFixedFixture, RecursiveTask) {
     auto executor = startAndGetServiceExecutor();
     auto barrier = std::make_shared<unittest::Barrier>(2);
 
-    ServiceExecutor::Task recursiveTask;
-    recursiveTask = [this, executor, barrier, &recursiveTask] {
+    std::function<void()> recursiveTask;
+    recursiveTask = [&, barrier] {
         auto recursionGuard = makeRecursionGuard();
         if (getRecursionDepth() < fixedServiceExecutorRecursionLimit.load()) {
             ASSERT_OK(executor->schedule(recursiveTask, ServiceExecutor::kMayRecurse));
@@ -257,8 +257,8 @@ TEST_F(ServiceExecutorFixedFixture, FlattenRecursiveScheduledTasks) {
     // A recursive task that expects to be executed non-recursively. The task recursively schedules
     // "tasksToSchedule" tasks to the service executor, and each scheduled task verifies that the
     // recursion depth remains zero during its execution.
-    ServiceExecutor::Task recursiveTask;
-    recursiveTask = [this, executor, barrier, &recursiveTask, &tasksToSchedule] {
+    std::function<void()> recursiveTask;
+    recursiveTask = [&, barrier] {
         auto recursionGuard = makeRecursionGuard();
         ASSERT_EQ(getRecursionDepth(), 1);
         if (tasksToSchedule.fetchAndSubtract(1) > 0) {