Only use TerminateThread when explicitly requested by the user by calling

asio::detail::thread::set_terminate_threads(true). This fixes a memory leak
that may occur with internally created threads.


[SVN r49201]

include/boost/asio/detail/null_thread.hpp

@@ -39,12 +39,9 @@ class null_thread
   : private noncopyable
 {
 public:
-  // The purpose of the thread.
-  enum purpose { internal, external };
-
   // Constructor.
   template <typename Function>
-  null_thread(Function f, purpose = internal)
+  null_thread(Function f)
   {
     boost::system::system_error e(
         boost::asio::error::operation_not_supported, "thread");

include/boost/asio/detail/posix_thread.hpp

@@ -43,12 +43,9 @@ class posix_thread
   : private noncopyable
 {
 public:
-  // The purpose of the thread.
-  enum purpose { internal, external };
-
   // Constructor.
   template <typename Function>
-  posix_thread(Function f, purpose = internal)
+  posix_thread(Function f)
     : joined_(false)
   {
     std::auto_ptr<func_base> arg(new func<Function>(f));

include/boost/asio/detail/win_thread.hpp

@@ -40,50 +40,67 @@ namespace detail {
 
 unsigned int __stdcall win_thread_function(void* arg);
 
-class win_thread
-  : private noncopyable
+#if (WINVER < 0x0500)
+void __stdcall apc_function(ULONG data);
+#else
+void __stdcall apc_function(ULONG_PTR data);
+#endif
+
+template <typename T>
+class win_thread_base
 {
 public:
-  // The purpose of the thread.
-  enum purpose { internal, external };
+  static bool terminate_threads()
+  {
+    return ::InterlockedExchangeAdd(&terminate_threads_, 0) != 0;
+  }
 
+  static void set_terminate_threads(bool b)
+  {
+    ::InterlockedExchange(&terminate_threads_, b ? 1 : 0);
+  }
+
+private:
+  static long terminate_threads_;
+};
+
+template <typename T>
+long win_thread_base<T>::terminate_threads_ = 0;
+
+class win_thread
+  : private noncopyable,
+    public win_thread_base<win_thread>
+{
+public:
   // Constructor.
   template <typename Function>
-  win_thread(Function f, purpose p = internal)
+  win_thread(Function f)
     : exit_event_(0)
   {
     std::auto_ptr<func_base> arg(new func<Function>(f));
 
     ::HANDLE entry_event = 0;
-    if (p == internal)
+    arg->entry_event_ = entry_event = ::CreateEvent(0, true, false, 0);
+    if (!entry_event)
     {
-      arg->entry_event_ = entry_event = ::CreateEvent(0, true, false, 0);
-      if (!entry_event)
-      {
-        DWORD last_error = ::GetLastError();
-        boost::system::system_error e(
-            boost::system::error_code(last_error,
-              boost::asio::error::get_system_category()),
-            "thread.entry_event");
-        boost::throw_exception(e);
-      }
-
-      arg->exit_event_ = exit_event_ = ::CreateEvent(0, true, false, 0);
-      if (!exit_event_)
-      {
-        DWORD last_error = ::GetLastError();
-        ::CloseHandle(entry_event);
-        boost::system::system_error e(
-            boost::system::error_code(last_error,
-              boost::asio::error::get_system_category()),
-            "thread.exit_event");
-        boost::throw_exception(e);
-      }
+      DWORD last_error = ::GetLastError();
+      boost::system::system_error e(
+          boost::system::error_code(last_error,
+            boost::asio::error::get_system_category()),
+          "thread.entry_event");
+      boost::throw_exception(e);
     }
-    else
+
+    arg->exit_event_ = exit_event_ = ::CreateEvent(0, true, false, 0);
+    if (!exit_event_)
     {
-      arg->entry_event_ = 0;
-      arg->exit_event_ = 0;
+      DWORD last_error = ::GetLastError();
+      ::CloseHandle(entry_event);
+      boost::system::system_error e(
+          boost::system::error_code(last_error,
+            boost::asio::error::get_system_category()),
+          "thread.exit_event");
+      boost::throw_exception(e);
     }
 
     unsigned int thread_id = 0;
@@ -123,14 +140,15 @@ public:
   // Wait for the thread to exit.
   void join()
   {
-    if (exit_event_)
+    ::WaitForSingleObject(exit_event_, INFINITE);
+    ::CloseHandle(exit_event_);
+    if (terminate_threads())
     {
-      ::WaitForSingleObject(exit_event_, INFINITE);
-      ::CloseHandle(exit_event_);
       ::TerminateThread(thread_, 0);
     }
     else
     {
+      ::QueueUserAPC(apc_function, thread_, 0);
       ::WaitForSingleObject(thread_, INFINITE);
     }
   }
@@ -138,6 +156,12 @@ public:
 private:
   friend unsigned int __stdcall win_thread_function(void* arg);
 
+#if (WINVER < 0x0500)
+  friend void __stdcall apc_function(ULONG);
+#else
+  friend void __stdcall apc_function(ULONG_PTR);
+#endif
+
   class func_base
   {
   public:
@@ -175,21 +199,30 @@ inline unsigned int __stdcall win_thread_function(void* arg)
   std::auto_ptr<win_thread::func_base> func(
       static_cast<win_thread::func_base*>(arg));
 
-  if (func->entry_event_)
-    ::SetEvent(func->entry_event_);
+  ::SetEvent(func->entry_event_);
 
   func->run();
 
-  if (HANDLE exit_event = func->exit_event_)
-  {
-    func.reset();
-    ::SetEvent(exit_event);
-    ::Sleep(INFINITE);
-  }
+  // Signal that the thread has finished its work, but rather than returning go
+  // to sleep to put the thread into a well known state. If the thread is being
+  // joined during global object destruction then it may be killed using
+  // TerminateThread (to avoid a deadlock in DllMain). Otherwise, the SleepEx
+  // call will be interrupted using QueueUserAPC and the thread will shut down
+  // cleanly.
+  HANDLE exit_event = func->exit_event_;
+  func.reset();
+  ::SetEvent(exit_event);
+  ::SleepEx(INFINITE, TRUE);
 
   return 0;
 }
 
+#if (WINVER < 0x0500)
+inline void __stdcall apc_function(ULONG) {}
+#else
+inline void __stdcall apc_function(ULONG_PTR) {}
+#endif
+
 } // namespace detail
 } // namespace asio
 } // namespace boost

include/boost/asio/detail/wince_thread.hpp

@@ -43,12 +43,9 @@ class wince_thread
   : private noncopyable
 {
 public:
-  // The purpose of the thread.
-  enum purpose { internal, external };
-
   // Constructor.
   template <typename Function>
-  wince_thread(Function f, purpose = internal)
+  wince_thread(Function f)
   {
     std::auto_ptr<func_base> arg(new func<Function>(f));
     DWORD thread_id = 0;