1 files changed, 69 insertions, 0 deletions

diff --git a/src/common/synchronized_wrapper.h b/src/common/synchronized_wrapper.h
new file mode 100644
index 000000000..946252b8c
--- /dev/null
+++ b/src/common/synchronized_wrapper.h
@@ -0,0 +1,69 @@
+// Copyright 2015 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <mutex>
+
+namespace Common {
+
+/**
+ * Wraps an object, only allowing access to it via a locking reference wrapper. Good to ensure no
+ * one forgets to lock a mutex before acessing an object. To access the wrapped object construct a
+ * SyncronizedRef on this wrapper. Inspired by Rust's Mutex type (http://doc.rust-lang.org/std/sync/struct.Mutex.html).
+ */
+template <typename T>
+class SynchronizedWrapper {
+public:
+    template <typename... Args>
+    SynchronizedWrapper(Args&&... args) :
+        data(std::forward<Args>(args)...) {
+    }
+
+private:
+    template <typename U>
+    friend class SynchronizedRef;
+
+    std::mutex mutex;
+    T data;
+};
+
+/**
+ * Synchronized reference, that keeps a SynchronizedWrapper's mutex locked during its lifetime. This
+ * greatly reduces the chance that someone will access the wrapped resource without locking the
+ * mutex.
+ */
+template <typename T>
+class SynchronizedRef {
+public:
+    SynchronizedRef(SynchronizedWrapper<T>& wrapper) : wrapper(&wrapper) {
+        wrapper.mutex.lock();
+    }
+
+    SynchronizedRef(SynchronizedRef&) = delete;
+    SynchronizedRef(SynchronizedRef&& o) : wrapper(o.wrapper) {
+        o.wrapper = nullptr;
+    }
+
+    ~SynchronizedRef() {
+        if (wrapper)
+            wrapper->mutex.unlock();
+    }
+
+    SynchronizedRef& operator=(SynchronizedRef&) = delete;
+    SynchronizedRef& operator=(SynchronizedRef&& o) {
+        std::swap(wrapper, o.wrapper);
+    }
+
+    T& operator*() { return wrapper->data; }
+    const T& operator*() const { return wrapper->data; }
+
+    T* operator->() { return &wrapper->data; }
+    const T* operator->() const { return &wrapper->data; }
+
+private:
+    SynchronizedWrapper<T>* wrapper;
+};
+
+} // namespace Common