Page Speed Optimization Libraries
1.3.25.1
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00001 /* 00002 * Copyright 2011 Google Inc. 00003 * 00004 * Licensed under the Apache License, Version 2.0 (the "License"); 00005 * you may not use this file except in compliance with the License. 00006 * You may obtain a copy of the License at 00007 * 00008 * http:///www.apache.org/licenses/LICENSE-2.0 00009 * 00010 * Unless required by applicable law or agreed to in writing, software 00011 * distributed under the License is distributed on an "AS IS" BASIS, 00012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 00013 * See the License for the specific language governing permissions and 00014 * limitations under the License. 00015 */ 00016 00043 00044 00045 #ifndef NET_INSTAWEB_UTIL_PUBLIC_REF_COUNTED_OWNER_H_ 00046 #define NET_INSTAWEB_UTIL_PUBLIC_REF_COUNTED_OWNER_H_ 00047 00048 #include "base/logging.h" 00049 #include "net/instaweb/util/public/basictypes.h" 00050 00052 template<typename T> 00053 class RefCountedOwner { 00054 public: 00055 class Family { 00056 public: 00057 Family() : ptr_(NULL), ref_count_(0) {} 00058 00059 private: 00060 friend class RefCountedOwner<T>; 00061 T* ptr_; 00062 int ref_count_; 00063 DISALLOW_COPY_AND_ASSIGN(Family); 00064 }; 00065 00068 explicit RefCountedOwner(Family* family) 00069 : family_(family), 00070 attached_(false) {} 00071 00072 ~RefCountedOwner() { 00073 if (attached_) { 00074 --family_->ref_count_; 00075 if (family_->ref_count_ == 0) { 00076 delete family_->ptr_; 00077 family_->ptr_ = NULL; 00078 } 00079 } 00080 } 00081 00088 bool Attach() { 00089 if (attached_) { 00090 return true; 00091 } else if (family_->ref_count_ != 0) { 00093 attached_ = true; 00094 ++family_->ref_count_; 00095 return true; 00096 } else { 00098 return false; 00099 } 00100 } 00101 00105 void Initialize(T* value) { 00106 CHECK(!attached_ && family_->ref_count_ == 0); 00107 attached_ = true; 00108 family_->ref_count_ = 1; 00109 family_->ptr_ = value; 00110 } 00111 00114 T* Get() { 00115 DCHECK(attached_); 00116 return family_->ptr_; 00117 } 00118 00119 const T* Get() const { 00120 DCHECK(attached_); 00121 return family_->ptr_; 00122 } 00123 00124 private: 00125 friend class Family; 00126 Family* family_; 00127 bool attached_; 00128 DISALLOW_COPY_AND_ASSIGN(RefCountedOwner); 00129 }; 00130 00131 #endif ///< NET_INSTAWEB_UTIL_PUBLIC_REF_COUNTED_OWNER_H_