From cc8c35cee5de7fdf2d79a1a3716120b64301cdfe Mon Sep 17 00:00:00 2001
From: Jean-Baptiste Queru <jbq@google.com>
Date: Thu, 12 Nov 2009 18:45:53 -0800
Subject: eclair snapshot

---
 include/utils/Singleton.h | 69 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 69 insertions(+)
 create mode 100644 include/utils/Singleton.h

(limited to 'include/utils/Singleton.h')

diff --git a/include/utils/Singleton.h b/include/utils/Singleton.h
new file mode 100644
index 0000000000..bc7626a821
--- /dev/null
+++ b/include/utils/Singleton.h
@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2007 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_UTILS_SINGLETON_H
+#define ANDROID_UTILS_SINGLETON_H
+
+#include <stdint.h>
+#include <sys/types.h>
+#include <utils/threads.h>
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+template <typename TYPE>
+class Singleton
+{
+public:
+    static TYPE& getInstance() {
+        Mutex::Autolock _l(sLock);
+        TYPE* instance = sInstance;
+        if (instance == 0) {
+            instance = new TYPE();
+            sInstance = instance;
+        }
+        return *instance;
+    }
+    
+protected:
+    ~Singleton() { };
+    Singleton() { };
+
+private:
+    Singleton(const Singleton&);
+    Singleton& operator = (const Singleton&);
+    static Mutex sLock;
+    static TYPE* sInstance;
+};
+
+/*
+ * use ANDROID_SINGLETON_STATIC_INSTANCE(TYPE) in your implementation file
+ * (eg: <TYPE>.cpp) to create the static instance of Singleton<>'s attributes,
+ * and avoid to have a copy of them in each compilation units Singleton<TYPE>
+ * is used.
+ */
+
+#define ANDROID_SINGLETON_STATIC_INSTANCE(TYPE)             \
+    template class Singleton< TYPE >;                       \
+    template< class TYPE > Mutex Singleton< TYPE >::sLock;  \
+    template<> TYPE* Singleton< TYPE >::sInstance(0);
+
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
+#endif // ANDROID_UTILS_SINGLETON_H
+
-- 
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