os: implement SdkRecursiveMutex

libraries/libstratosphere/source/os/os_sdk_condition_variable.cpp

@@ -45,4 +45,58 @@ namespace ams::os {
         return status == ConditionVariableStatus::Success;
     }
 
+    void SdkConditionVariableType::Wait(SdkRecursiveMutexType &mutex) {
+        /* Check preconditions. */
+        AMS_ABORT_UNLESS(os::IsSdkRecursiveMutexLockedByCurrentThread(std::addressof(mutex)));
+        AMS_ABORT_UNLESS(mutex.recursive_count == 1);
+
+        /* Decrement the mutex's recursive count. */
+        --mutex.recursive_count;
+
+        /* Wait on the mutex. */
+        GetReference(this->_storage).Wait(GetPointer(mutex._storage));
+
+        /* Increment the mutex's recursive count. */
+        ++mutex.recursive_count;
+
+        /* Check that the mutex's recursive count is valid. */
+        AMS_ABORT_UNLESS(mutex.recursive_count != 0);
+    }
+
+    bool SdkConditionVariableType::TimedWait(SdkRecursiveMutexType &mutex, TimeSpan timeout) {
+        /* Check preconditions. */
+        AMS_ASSERT(timeout.GetNanoSeconds() >= 0);
+        AMS_ABORT_UNLESS(os::IsSdkRecursiveMutexLockedByCurrentThread(std::addressof(mutex)));
+
+        /* Handle zero timeout by unlocking and re-locking. */
+        if (timeout == TimeSpan(0)) {
+            /* NOTE: Nintendo doesn't check recursive_count here...seems really suspicious? */
+            /*       Not sure that this is correct, or if they just forgot to check. */
+            GetReference(mutex._storage).Leave();
+            GetReference(mutex._storage).Enter();
+            return false;
+        }
+
+        /* Check that the mutex is held exactly once. */
+        AMS_ABORT_UNLESS(mutex.recursive_count == 1);
+
+        /* Decrement the mutex's recursive count. */
+        --mutex.recursive_count;
+
+        /* Create timeout helper. */
+        impl::TimeoutHelper timeout_helper(timeout);
+
+        /* Perform timed wait. */
+        auto status = GetReference(this->_storage).TimedWait(GetPointer(mutex._storage), timeout_helper);
+
+        /* Increment the mutex's recursive count. */
+        ++mutex.recursive_count;
+
+        /* Check that the mutex's recursive count is valid. */
+        AMS_ABORT_UNLESS(mutex.recursive_count != 0);
+
+        /* Return whether we succeeded. */
+        return status == ConditionVariableStatus::Success;
+    }
+
 }