| 1 | // Copyright (C) 2012 Vicente Botet |
|---|---|
| 2 | // |
| 3 | // Distributed under the Boost Software License, Version 1.0. (See accompanying |
| 4 | // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
| 5 | |
| 6 | #define BOOST_THREAD_VERSION 4 |
| 7 | |
| 8 | #include <boost/thread/mutex.hpp> |
| 9 | #include <boost/thread/lockable_adapter.hpp> |
| 10 | #include <boost/thread/externally_locked.hpp> |
| 11 | #include <boost/thread/strict_lock.hpp> |
| 12 | #include <boost/thread/lock_types.hpp> |
| 13 | #include <iostream> |
| 14 | |
| 15 | #ifdef BOOST_MSVC |
| 16 | # pragma warning(disable: 4355) // 'this' : used in base member initializer list |
| 17 | #endif |
| 18 | |
| 19 | using namespace boost; |
| 20 | |
| 21 | class BankAccount |
| 22 | { |
| 23 | int balance_; |
| 24 | public: |
| 25 | void Deposit(int amount) |
| 26 | { |
| 27 | balance_ += amount; |
| 28 | } |
| 29 | void Withdraw(int amount) |
| 30 | { |
| 31 | balance_ -= amount; |
| 32 | } |
| 33 | int GetBalance() |
| 34 | { |
| 35 | return balance_; |
| 36 | } |
| 37 | }; |
| 38 | |
| 39 | //[AccountManager |
| 40 | class AccountManager: public basic_lockable_adapter<mutex> |
| 41 | { |
| 42 | public: |
| 43 | typedef basic_lockable_adapter<mutex> lockable_base_type; |
| 44 | AccountManager() : |
| 45 | lockable_base_type(), checkingAcct_(*this), savingsAcct_(*this) |
| 46 | { |
| 47 | } |
| 48 | inline void Checking2Savings(int amount); |
| 49 | inline void AMoreComplicatedChecking2Savings(int amount); |
| 50 | private: |
| 51 | /*<-*/ |
| 52 | bool some_condition() |
| 53 | { |
| 54 | return true; |
| 55 | } /*->*/ |
| 56 | externally_locked<BankAccount, AccountManager > checkingAcct_; |
| 57 | externally_locked<BankAccount, AccountManager > savingsAcct_; |
| 58 | }; |
| 59 | //] |
| 60 | |
| 61 | //[Checking2Savings |
| 62 | void AccountManager::Checking2Savings(int amount) |
| 63 | { |
| 64 | strict_lock<AccountManager> guard(*this); |
| 65 | checkingAcct_.get(lk&: guard).Withdraw(amount); |
| 66 | savingsAcct_.get(lk&: guard).Deposit(amount); |
| 67 | } |
| 68 | //] |
| 69 | |
| 70 | //#if DO_NOT_COMPILE |
| 71 | ////[AMoreComplicatedChecking2Savings_DO_NOT_COMPILE |
| 72 | //void AccountManager::AMoreComplicatedChecking2Savings(int amount) { |
| 73 | // unique_lock<AccountManager> guard(*this); |
| 74 | // if (some_condition()) { |
| 75 | // guard.lock(); |
| 76 | // } |
| 77 | // checkingAcct_.get(guard).Withdraw(amount); |
| 78 | // savingsAcct_.get(guard).Deposit(amount); |
| 79 | // guard1.unlock(); |
| 80 | //} |
| 81 | ////] |
| 82 | //#elif DO_NOT_COMPILE_2 |
| 83 | ////[AMoreComplicatedChecking2Savings_DO_NOT_COMPILE2 |
| 84 | //void AccountManager::AMoreComplicatedChecking2Savings(int amount) { |
| 85 | // unique_lock<AccountManager> guard1(*this); |
| 86 | // if (some_condition()) { |
| 87 | // guard1.lock(); |
| 88 | // } |
| 89 | // { |
| 90 | // strict_lock<AccountManager> guard(guard1); |
| 91 | // checkingAcct_.get(guard).Withdraw(amount); |
| 92 | // savingsAcct_.get(guard).Deposit(amount); |
| 93 | // } |
| 94 | // guard1.unlock(); |
| 95 | //} |
| 96 | ////] |
| 97 | //#else |
| 98 | ////[AMoreComplicatedChecking2Savings |
| 99 | void AccountManager::AMoreComplicatedChecking2Savings(int amount) { |
| 100 | unique_lock<AccountManager> guard1(*this); |
| 101 | if (some_condition()) { |
| 102 | guard1.lock(); |
| 103 | } |
| 104 | { |
| 105 | nested_strict_lock<unique_lock<AccountManager> > guard(guard1); |
| 106 | checkingAcct_.get(lk&: guard).Withdraw(amount); |
| 107 | savingsAcct_.get(lk&: guard).Deposit(amount); |
| 108 | } |
| 109 | guard1.unlock(); |
| 110 | } |
| 111 | ////] |
| 112 | //#endif |
| 113 | |
| 114 | int main() |
| 115 | { |
| 116 | AccountManager mgr; |
| 117 | mgr.Checking2Savings(amount: 100); |
| 118 | return 0; |
| 119 | } |
| 120 | |
| 121 |