Synced Chapter05 recipes [2,6]

Chapter05/02_mutex/main.cpp

@@ -4,6 +4,7 @@
 // In previous recipe we included
 // <boost/thread.hpp>, which includes all
 // the classes of Boost.Thread.
+// Following header includes only boost::thread.
 #include <boost/thread/thread.hpp>
 
 namespace without_sync {

Chapter05/03_atomics/main.cpp

@@ -8,23 +8,19 @@ boost::atomic<int> shared_i(0);
 
 void do_inc() {
     for (std::size_t i = 0; i < 30000; ++i) {
-        // do some work
-        // ...
         const int i_snapshot = ++ shared_i;
 
-        // do some work with i_snapshot
+        // Do some work with i_snapshot.
         // ...
         (void) i_snapshot;
     }
 }
 
 void do_dec() {
     for (std::size_t i = 0; i < 30000; ++i) {
-        // do some work
-        // ...
         const int i_snapshot = -- shared_i;
 
-        // do some work with i_snapshot
+        // Do some work with i_snapshot.
         // ...
         (void) i_snapshot;
     }

Chapter05/04_work_queue/main.cpp

@@ -9,8 +9,8 @@ class work_queue {
     typedef boost::function<void()> task_type;
 
 private:
-    std::deque<task_type>   tasks_;
-    boost::mutex            tasks_mutex_;
+    std::deque<task_type>     tasks_;
+    boost::mutex              tasks_mutex_;
     boost::condition_variable cond_;
 
 public:
@@ -61,19 +61,19 @@ class work_queue {
 
 work_queue g_queue;
 
-void do_nothing(){}
+void some_task();
 const std::size_t tests_tasks_count = 3000 /*000*/;
+
 void pusher() {
     for (std::size_t i = 0; i < tests_tasks_count; ++i) {
-        // Adding task to do nothing
-        g_queue.push_task(&do_nothing);
+        g_queue.push_task(&some_task);
     }
 }
 
 void popper_sync() {
     for (std::size_t i = 0; i < tests_tasks_count; ++i) {
-        g_queue.pop_task() // Getting task
-                (); // Executing task
+        work_queue::task_type t = g_queue.pop_task();
+        t();         // Executing task.
     }
 }
 
@@ -86,25 +86,27 @@ int main() {
     boost::thread push2(&pusher);
     boost::thread push3(&pusher);
 
-    // Waiting for all the tasks to push
+    // Waiting for all the tasks to push.
     push1.join();
     push2.join();
     push3.join();
-    g_queue.flush(); 
+    g_queue.flush();
 
-    // Waiting for all the tasks to pop
+    // Waiting for all the tasks to pop.
     pop_sync1.join();
     pop_sync2.join();
     pop_sync3.join();
 
 
     // Asserting that no tasks remained,
-    // and falling though without blocking
+    // and falling though without blocking.
     assert(!g_queue.try_pop_task());
 
-    g_queue.push_task(&do_nothing);
+    g_queue.push_task(&some_task);
+
     // Asserting that there is a task,
-    // and falling though without blocking
+    // and falling though without blocking.
     assert(g_queue.try_pop_task());
-
 }
+
+void some_task() { /* do nothing */ }

Chapter05/05_shared_lock/05_shared_lock.pro

@@ -2,5 +2,6 @@ if (!include(../../config.txt)) {
     error("Failed to open config.txt")
 }
 
+QMAKE_CXXFLAGS += $$CPP11FLAG
 SOURCES += main.cpp
 LIBS += -lboost_thread -lboost_system

Chapter05/05_shared_lock/main.cpp

@@ -1,7 +1,9 @@
-#include <map>
+#include <unordered_map>
 #include <boost/thread/mutex.hpp>
 #include <boost/thread/locks.hpp>
 
+namespace first_example {
+
 struct user_info {
     std::string address;
     unsigned short age;
@@ -10,61 +12,64 @@ struct user_info {
     // ...
 };
 
-namespace first_example {
-
 class users_online {
-    typedef boost::mutex                mutex_t;
-    mutable mutex_t                     users_mutex_;
-    std::map<std::string, user_info>    users_;
+    typedef boost::mutex mutex_t;
+
+    mutable mutex_t                             users_mutex_;
+    std::unordered_map<std::string, user_info>  users_;
 
 public:
     bool is_online(const std::string& username) const {
         boost::lock_guard<mutex_t> lock(users_mutex_);
         return users_.find(username) != users_.end();
     }
 
-    unsigned short get_age(const std::string& username) const {
+    std::string get_address(const std::string& username) const {
         boost::lock_guard<mutex_t> lock(users_mutex_);
-        return users_.at(username).age;
+        return users_.at(username).address;
     }
 
-    void set_online(const std::string& username, const user_info& data) {
+    void set_online(const std::string& username, user_info&& data) {
         boost::lock_guard<mutex_t> lock(users_mutex_);
-        users_.insert(std::make_pair(username, data));
+        users_.insert(std::make_pair(username, std::move(data)));
     }
 
-    // Other methods
+    // Other methods:
     // ...
 };
 
 }
 
+using first_example::user_info;
+
 #include <boost/thread/shared_mutex.hpp>
 
 namespace shared_lock_example {
 
+
 class users_online {
-    typedef boost::shared_mutex         mutex_t;
-    mutable mutex_t                     users_mutex_;
-    std::map<std::string, user_info>    users_;
+    typedef boost::shared_mutex mutex_t;
+
+    mutable mutex_t                             users_mutex_;
+    std::unordered_map<std::string, user_info>  users_;
 
 public:
     bool is_online(const std::string& username) const {
         boost::shared_lock<mutex_t> lock(users_mutex_);
         return users_.find(username) != users_.end();
     }
 
-    unsigned short get_age(const std::string& username) const {
+    std::string get_address(const std::string& username) const {
         boost::shared_lock<mutex_t> lock(users_mutex_);
-        return users_.at(username).age;
+        return users_.at(username).address;
     }
 
     void set_online(const std::string& username, const user_info& data) {
         boost::lock_guard<mutex_t> lock(users_mutex_);
         users_.insert(std::make_pair(username, data));
     }
 
-    // Other methods
+    // Other methods:
     // ...
 };
 
@@ -87,7 +92,7 @@ void log_in(T& u, std::size_t count) {
 template <class T>
 void thread_get_age(T& u) {
     for (std::size_t i = 0; i < users_count; ++i) {
-        u.get_age(boost::lexical_cast<std::string>(i));
+        u.get_address(boost::lexical_cast<std::string>(i));
     }
 }
 

Chapter05/06_thread_specific_ptr/main.cpp

@@ -12,11 +12,11 @@ class connection: boost::noncopyable {
     connection(): open_count_(0) {}
 };
 
-// In header file
+// In header file:
 #include <boost/thread/tss.hpp>
 connection& get_connection();
 
-// In source file
+// In source file:
 boost::thread_specific_ptr<connection> connection_ptr;
 
 connection& get_connection() {
@@ -33,10 +33,10 @@ connection& get_connection() {
 
 void task() {
     int result = 2;
-    // Some computations go there
+    // Some computations go there.
     // ...
 
-    // Sending result
+    // Sending the result:
     get_connection().send_result(result);
 }
 
@@ -61,10 +61,9 @@ int main() {
     boost::thread t3(&run_tasks);
     boost::thread t4(&run_tasks);
 
-    // Waiting for all the tasks to pop
+    // Waiting for all the tasks to stop.
     t1.join();
     t2.join();
     t3.join();
     t4.join();
-
 }