From: dahyeong.kim <dahyeong.kim@samsung.com>
Date: Mon, 27 May 2013 08:20:01 +0000 (+0900)
Subject: Use atomic operation for Reference counting
X-Git-Tag: accepted/tizen/20130912.081851^2~291^2
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=81cb37643704dafd441119799598ea7e4936fabb;p=platform%2Fframework%2Fnative%2Fappfw.git

Use atomic operation for Reference counting

Change-Id: Icc9d415736013d641028696bbc840cdeca7c15f7
Signed-off-by: dahyeong.kim <dahyeong.kim@samsung.com>
---

diff --git a/inc/FBaseString.h b/inc/FBaseString.h
index 8cd87f9..f9b6fe0 100644
--- a/inc/FBaseString.h
+++ b/inc/FBaseString.h
@@ -1097,7 +1097,7 @@ private:
 	int __capacity;
 	int __length;
 	mutable int __hash;
-	mutable int* __pRefCount;
+	mutable volatile int* __pRefCount;
 	mutable wchar_t* __pValue;
 
 	static const float GROWTH_FACTOR;
diff --git a/src/base/FBaseString.cpp b/src/base/FBaseString.cpp
index 03ce90e..e5ff018 100644
--- a/src/base/FBaseString.cpp
+++ b/src/base/FBaseString.cpp
@@ -37,6 +37,7 @@
 #include <FBaseResult.h>
 #include <FBaseSysLog.h>
 #include <unique_ptr.h>
+#include "FBase_String.h"
 
 
 namespace Tizen { namespace Base
@@ -158,7 +159,7 @@ String::String(const String& value)
 {
 	SysTryReturnVoidResult(NID_BASE, value.__length >= 0, E_OUT_OF_RANGE, "The length has to be greater than 0.");
 
-	++(*value.__pRefCount);
+	_String::AtomicInc(value.__pRefCount);
 	__pRefCount = value.__pRefCount;
 }
 
@@ -171,7 +172,7 @@ String::~String(void)
 	}
 	else
 	{
-		(*__pRefCount)--;
+		_String::AtomicDec(__pRefCount);
 		__pRefCount = null;
 	}
 }
@@ -378,7 +379,7 @@ String::Append(const wchar_t* p)
 		SysTryReturnResult(NID_BASE, pRefCntTemp != null, E_OUT_OF_MEMORY, "Memory allocation failed");
 
 		wcsncpy(__pValue, pValue, __length);
-		(*__pRefCount)--;
+		_String::AtomicDec(__pRefCount);
 		__pRefCount = pRefCntTemp.release();
 	}
 
@@ -1044,7 +1045,7 @@ String::SetCapacity(int capacity)
 		{
 			std::unique_ptr<int> pRefCntTemp(new (std::nothrow) int(1));
 			SysTryReturnResult(NID_BASE, pRefCntTemp != null, E_OUT_OF_MEMORY, "Memory allocation failed");
-			(*__pRefCount)--;
+			_String::AtomicDec(__pRefCount);
 			__pRefCount = pRefCntTemp.release();
 		}
 	}
@@ -1514,7 +1515,7 @@ String::ExpandCapacity(int minCapacity)
 			std::unique_ptr<int> pRefCntTemp(new (std::nothrow) int(1));
 			SysTryReturn(NID_BASE, pRefCntTemp != null, false, E_OUT_OF_MEMORY, "[%s] Memory allocation failed",
 				GetErrorMessage(E_OUT_OF_MEMORY));
-			(*__pRefCount)--;
+			_String::AtomicDec(__pRefCount);
 			__pRefCount = pRefCntTemp.release();
 		}
 	}
@@ -1546,7 +1547,7 @@ String::CopyOnWrite(int capacity)
 
 	wcsncpy(__pValue, pValue, __length);
 	__pValue[__length] = '\0';
-	--(*__pRefCount);
+	_String::AtomicDec(__pRefCount);
 	__pRefCount = pRefCntTemp.release();
 	return E_SUCCESS;
 }
diff --git a/src/base/inc/FBase_String.h b/src/base/inc/FBase_String.h
new file mode 100644
index 0000000..530968f
--- /dev/null
+++ b/src/base/inc/FBase_String.h
@@ -0,0 +1,78 @@
+//
+// Copyright (c) 2012 Samsung Electronics Co., Ltd.
+//
+// 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.
+//
+
+/**
+ * @file		FBase_String.h
+ * @brief		This is the header file for handling atomic operations.
+ */
+
+#ifndef _FBASE_INTERNAL_STRING_H_
+#define _FBASE_INTERNAL_STRING_H_
+
+namespace Tizen { namespace Base
+{
+namespace _String
+{
+
+/**
+ * Atomically add the value to the variable that pRefCount points to.
+ *
+ * @since 2.1
+ */
+inline int AtomicAdd(volatile int* pRefCount, int value)
+{
+#if defined(__arm__)
+	register int result;
+	asm volatile (
+		"1: ldrex   %0,  [%1]	\n\t"
+		"add     r1,   %0,  %2	\n\t"
+		"strex   r2,   r1, [%1]	\n\t"
+		"cmp     r2,   #0 \n\t"
+		"bne     1b"
+		: "=&r" (result)
+		: "r"(pRefCount), "r"(value)
+		: "r1","r2"
+	);
+	return result;
+#else
+	return __sync_fetch_and_add(pRefCount, value);
+#endif
+}
+
+/**
+ * Atomically increase the variable that pRefCount points to by 1
+ *
+ * @since 2.1
+ */
+inline int AtomicInc(volatile int* pRefCount)
+{
+	return AtomicAdd(pRefCount, 1);
+}
+
+/**
+ * Atomically decrease the variable that pRefCount points to by 1
+ *
+ * @since 2.1
+ */
+inline int AtomicDec(volatile int* pRefCount)
+{
+	return AtomicAdd(pRefCount, -1);
+}
+
+}// _String
+}}	// Tizen::Base
+
+#endif	// _FBASE_INTERNAL_STRING_H_
\ No newline at end of file