1 //===----------------------------------------------------------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is dual licensed under the MIT and the University of Illinois Open 6 // Source Licenses. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 // <deque> 11 12 // void push_front(const value_type& x); 13 14 #include <deque> 15 #include <cassert> 16 17 // Flag that makes the copy constructor for CMyClass throw an exception 18 static bool gCopyConstructorShouldThow = false; 19 20 21 class CMyClass { 22 public: CMyClass(int tag); 23 public: CMyClass(const CMyClass& iOther); 24 public: ~CMyClass(); 25 26 bool equal(const CMyClass &rhs) const 27 { return fTag == rhs.fTag && fMagicValue == rhs.fMagicValue; } 28 private: 29 int fMagicValue; 30 int fTag; 31 32 private: static int kStartedConstructionMagicValue; 33 private: static int kFinishedConstructionMagicValue; 34 }; 35 36 // Value for fMagicValue when the constructor has started running, but not yet finished 37 int CMyClass::kStartedConstructionMagicValue = 0; 38 // Value for fMagicValue when the constructor has finished running 39 int CMyClass::kFinishedConstructionMagicValue = 12345; 40 41 CMyClass::CMyClass(int tag) : 42 fMagicValue(kStartedConstructionMagicValue), fTag(tag) 43 { 44 // Signal that the constructor has finished running 45 fMagicValue = kFinishedConstructionMagicValue; 46 } 47 48 CMyClass::CMyClass(const CMyClass& iOther) : 49 fMagicValue(kStartedConstructionMagicValue), fTag(iOther.fTag) 50 { 51 // If requested, throw an exception _before_ setting fMagicValue to kFinishedConstructionMagicValue 52 if (gCopyConstructorShouldThow) { 53 throw std::exception(); 54 } 55 // Signal that the constructor has finished running 56 fMagicValue = kFinishedConstructionMagicValue; 57 } 58 59 CMyClass::~CMyClass() { 60 // Only instances for which the constructor has finished running should be destructed 61 assert(fMagicValue == kFinishedConstructionMagicValue); 62 } 63 64 bool operator==(const CMyClass &lhs, const CMyClass &rhs) { return lhs.equal(rhs); } 65 66 int main() 67 { 68 CMyClass instance(42); 69 std::deque<CMyClass> vec; 70 71 vec.push_front(instance); 72 std::deque<CMyClass> vec2(vec); 73 74 gCopyConstructorShouldThow = true; 75 try { 76 vec.push_front(instance); 77 } 78 catch (...) { 79 assert(vec==vec2); 80 } 81 } 82
