Port web_service from Citra

src/common/detached_tasks.cpp

@@ -0,0 +1,41 @@
+// Copyright 2018 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <thread>
+#include "common/assert.h"
+#include "common/detached_tasks.h"
+
+namespace Common {
+
+DetachedTasks* DetachedTasks::instance = nullptr;
+
+DetachedTasks::DetachedTasks() {
+    ASSERT(instance == nullptr);
+    instance = this;
+}
+
+void DetachedTasks::WaitForAllTasks() {
+    std::unique_lock<std::mutex> lock(mutex);
+    cv.wait(lock, [this]() { return count == 0; });
+}
+
+DetachedTasks::~DetachedTasks() {
+    std::unique_lock<std::mutex> lock(mutex);
+    ASSERT(count == 0);
+    instance = nullptr;
+}
+
+void DetachedTasks::AddTask(std::function<void()> task) {
+    std::unique_lock<std::mutex> lock(instance->mutex);
+    ++instance->count;
+    std::thread([task{std::move(task)}]() {
+        task();
+        std::unique_lock<std::mutex> lock(instance->mutex);
+        --instance->count;
+        std::notify_all_at_thread_exit(instance->cv, std::move(lock));
+    })
+        .detach();
+}
+
+} // namespace Common