platform_system_core/include/utils/Singleton.h
Colin Cross 17b5b82d64 Fix warnings in libutils headers
system/core/include is included in the global include path using
-isystem, which hides all warnings.  Fix warnings in libutils
headers in preparation for moving from -isystem to -I.

- Fix implicit cast from int64_t to long in Condition.h.  Remove
  the __LP64__ check and always compare against LONG_MAX before
  casting.
- Fix implicit cast from size_t to ssize_t in KeyedVector.h
- Fix -Wshadow-field-in-constructor warnings in Looper.h and RefBase.h
- Move destructors for MessageHandler and LooperCallback to Looper.cpp
  and ReferenceRenamer and VirtualLightRefBase to RefBase.cpp to prevent
  vtables in every compilation unit.
- Declare template variables in Singleton.h
- Fix old-style casts in StrongPointer.h and TypeHelpers.h
- Use template metaprogramming in TypeHelpers.h to avoid warnings on
  memmove on non-trivial types.
- Add an assignment operator to key_value_pair_t to complete
  rule-of-three
- Use memcpy instead of dereferencing a reinterpret_casted pointer to
  treat the bits of a float or double as int32_t or int64_t
- Escape unicode sequences inside doxygen comments between \code and
  \endcode
- Remove WIN32 ZD definition in Compat.h, %zd works fine with mingw
- Fix WIN32 printf warnings in Filemap.cpp
- Initialize mNullValue with 0 in LruCache.h, some of the tests use a
  non-pointer type for TValue.

Test: m -j native
Bug: 31492149
Change-Id: I385a05a3ca01258e44fe3b37ef77e4aaff547b26
2016-09-22 13:03:15 -07:00

85 lines
2.4 KiB
C++

/*
* 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/Mutex.h>
#include <utils/threads.h>
#include <cutils/compiler.h>
namespace android {
// ---------------------------------------------------------------------------
template <typename TYPE>
class ANDROID_API Singleton
{
public:
static TYPE& getInstance() {
Mutex::Autolock _l(sLock);
TYPE* instance = sInstance;
if (instance == 0) {
instance = new TYPE();
sInstance = instance;
}
return *instance;
}
static bool hasInstance() {
Mutex::Autolock _l(sLock);
return sInstance != 0;
}
protected:
~Singleton() { }
Singleton() { }
private:
Singleton(const Singleton&);
Singleton& operator = (const Singleton&);
static Mutex sLock;
static TYPE* sInstance;
};
template <typename TYPE>
Mutex Singleton<TYPE>::sLock;
template <typename TYPE>
TYPE* Singleton<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.
* NOTE: we use a version of Mutex ctor that takes a parameter, because
* for some unknown reason using the default ctor doesn't emit the variable!
*/
#define ANDROID_SINGLETON_STATIC_INSTANCE(TYPE) \
template<> ::android::Mutex \
(::android::Singleton< TYPE >::sLock)(::android::Mutex::PRIVATE); \
template<> TYPE* ::android::Singleton< TYPE >::sInstance(0); \
template class ::android::Singleton< TYPE >;
// ---------------------------------------------------------------------------
}; // namespace android
#endif // ANDROID_UTILS_SINGLETON_H