1 files changed, 134 insertions, 311 deletions
diff --git a/3rdParty/Boost/src/boost/asio/detail/strand_service.hpp b/3rdParty/Boost/src/boost/asio/detail/strand_service.hpp
index b228cec..d6b45b1 100644
--- a/3rdParty/Boost/src/boost/asio/detail/strand_service.hpp
+++ b/3rdParty/Boost/src/boost/asio/detail/strand_service.hpp
@@ -18,19 +18,19 @@
 #include <boost/asio/detail/push_options.hpp>
 
 #include <boost/asio/detail/push_options.hpp>
-#include <boost/aligned_storage.hpp>
-#include <boost/assert.hpp>
 #include <boost/functional/hash.hpp>
 #include <boost/scoped_ptr.hpp>
 #include <boost/asio/detail/pop_options.hpp>
 
 #include <boost/asio/io_service.hpp>
-#include <boost/asio/detail/bind_handler.hpp>
 #include <boost/asio/detail/call_stack.hpp>
+#include <boost/asio/detail/completion_handler.hpp>
+#include <boost/asio/detail/fenced_block.hpp>
 #include <boost/asio/detail/handler_alloc_helpers.hpp>
 #include <boost/asio/detail/handler_invoke_helpers.hpp>
 #include <boost/asio/detail/mutex.hpp>
-#include <boost/asio/detail/noncopyable.hpp>
+#include <boost/asio/detail/op_queue.hpp>
+#include <boost/asio/detail/operation.hpp>
 #include <boost/asio/detail/service_base.hpp>
 
 namespace boost {
@@ -41,252 +41,45 @@ namespace detail {
 class strand_service
   : public boost::asio::detail::service_base<strand_service>
 {
+private:
+  struct on_do_complete_exit;
+  struct on_dispatch_exit;
+
 public:
-  class handler_base;
-  class invoke_current_handler;
-  class post_next_waiter_on_exit;
 
   // The underlying implementation of a strand.
   class strand_impl
+    : public operation
   {
   public:
     strand_impl()
-      : current_handler_(0),
-        first_waiter_(0),
-        last_waiter_(0)
+      : operation(&strand_service::do_complete),
+        count_(0)
     {
     }
 
   private:
     // Only this service will have access to the internal values.
     friend class strand_service;
-    friend class post_next_waiter_on_exit;
-    friend class invoke_current_handler;
+    friend struct on_do_complete_exit;
+    friend struct on_dispatch_exit;
 
     // Mutex to protect access to internal data.
     boost::asio::detail::mutex mutex_;
 
-    // The handler that is ready to execute. If this pointer is non-null then it
-    // indicates that a handler holds the lock.
-    handler_base* current_handler_;
-
-    // The start of the list of waiting handlers for the strand.
-    handler_base* first_waiter_;
-    
-    // The end of the list of waiting handlers for the strand.
-    handler_base* last_waiter_;
-
-    // Storage for posted handlers.
-    typedef boost::aligned_storage<128> handler_storage_type;
-#if defined(__BORLANDC__)
-    boost::aligned_storage<128> handler_storage_;
-#else
-    handler_storage_type handler_storage_;
-#endif
-  };
-
-  friend class strand_impl;
-
-  typedef strand_impl* implementation_type;
-
-  // Base class for all handler types.
-  class handler_base
-  {
-  public:
-    typedef void (*invoke_func_type)(handler_base*,
-        strand_service&, implementation_type&);
-    typedef void (*destroy_func_type)(handler_base*);
-
-    handler_base(invoke_func_type invoke_func, destroy_func_type destroy_func)
-      : next_(0),
-        invoke_func_(invoke_func),
-        destroy_func_(destroy_func)
-    {
-    }
-
-    void invoke(strand_service& service_impl, implementation_type& impl)
-    {
-      invoke_func_(this, service_impl, impl);
-    }
-
-    void destroy()
-    {
-      destroy_func_(this);
-    }
-
-  protected:
-    ~handler_base()
-    {
-    }
-
-  private:
-    friend class strand_service;
-    friend class strand_impl;
-    friend class post_next_waiter_on_exit;
-    handler_base* next_;
-    invoke_func_type invoke_func_;
-    destroy_func_type destroy_func_;
-  };
-
-  // Helper class to allow handlers to be dispatched.
-  class invoke_current_handler
-  {
-  public:
-    invoke_current_handler(strand_service& service_impl,
-        const implementation_type& impl)
-      : service_impl_(service_impl),
-        impl_(impl)
-    {
-    }
-
-    void operator()()
-    {
-      impl_->current_handler_->invoke(service_impl_, impl_);
-    }
-
-    friend void* asio_handler_allocate(std::size_t size,
-        invoke_current_handler* this_handler)
-    {
-      return this_handler->do_handler_allocate(size);
-    }
-
-    friend void asio_handler_deallocate(void*, std::size_t,
-        invoke_current_handler*)
-    {
-    }
-
-    void* do_handler_allocate(std::size_t size)
-    {
-#if defined(__BORLANDC__)
-      BOOST_ASSERT(size <= boost::aligned_storage<128>::size);
-#else
-      BOOST_ASSERT(size <= strand_impl::handler_storage_type::size);
-#endif
-      (void)size;
-      return impl_->handler_storage_.address();
-    }
-
-    // The asio_handler_invoke hook is not defined here since the default one
-    // provides the correct behaviour, and including it here breaks MSVC 7.1
-    // in some situations.
-
-  private:
-    strand_service& service_impl_;
-    implementation_type impl_;
-  };
-
-  // Helper class to automatically enqueue next waiter on block exit.
-  class post_next_waiter_on_exit
-  {
-  public:
-    post_next_waiter_on_exit(strand_service& service_impl,
-        implementation_type& impl)
-      : service_impl_(service_impl),
-        impl_(impl),
-        cancelled_(false)
-    {
-    }
-
-    ~post_next_waiter_on_exit()
-    {
-      if (!cancelled_)
-      {
-        boost::asio::detail::mutex::scoped_lock lock(impl_->mutex_);
-        impl_->current_handler_ = impl_->first_waiter_;
-        if (impl_->current_handler_)
-        {
-          impl_->first_waiter_ = impl_->first_waiter_->next_;
-          if (impl_->first_waiter_ == 0)
-            impl_->last_waiter_ = 0;
-          lock.unlock();
-          service_impl_.get_io_service().post(
-              invoke_current_handler(service_impl_, impl_));
-        }
-      }
-    }
-
-    void cancel()
-    {
-      cancelled_ = true;
-    }
+    // The count of handlers in the strand, including the upcall (if any).
+    std::size_t count_;
 
-  private:
-    strand_service& service_impl_;
-    implementation_type& impl_;
-    bool cancelled_;
+    // The handlers waiting on the strand.
+    op_queue<operation> queue_;
   };
 
-  // Class template for a waiter.
-  template <typename Handler>
-  class handler_wrapper
-    : public handler_base
-  {
-  public:
-    handler_wrapper(Handler handler)
-      : handler_base(&handler_wrapper<Handler>::do_invoke,
-          &handler_wrapper<Handler>::do_destroy),
-        handler_(handler)
-    {
-    }
-
-    static void do_invoke(handler_base* base,
-        strand_service& service_impl, implementation_type& impl)
-    {
-      // Take ownership of the handler object.
-      typedef handler_wrapper<Handler> this_type;
-      this_type* h(static_cast<this_type*>(base));
-      typedef handler_alloc_traits<Handler, this_type> alloc_traits;
-      handler_ptr<alloc_traits> ptr(h->handler_, h);
-
-      post_next_waiter_on_exit p1(service_impl, impl);
-
-      // Make a copy of the handler so that the memory can be deallocated before
-      // the upcall is made.
-      Handler handler(h->handler_);
-
-      // A handler object must still be valid when the next waiter is posted
-      // since destroying the last handler might cause the strand object to be
-      // destroyed. Therefore we create a second post_next_waiter_on_exit object
-      // that will be destroyed before the handler object.
-      p1.cancel();
-      post_next_waiter_on_exit p2(service_impl, impl);
-
-      // Free the memory associated with the handler.
-      ptr.reset();
-
-      // Indicate that this strand is executing on the current thread.
-      call_stack<strand_impl>::context ctx(impl);
-
-      // Make the upcall.
-      boost_asio_handler_invoke_helpers::invoke(handler, handler);
-    }
-
-    static void do_destroy(handler_base* base)
-    {
-      // Take ownership of the handler object.
-      typedef handler_wrapper<Handler> this_type;
-      this_type* h(static_cast<this_type*>(base));
-      typedef handler_alloc_traits<Handler, this_type> alloc_traits;
-      handler_ptr<alloc_traits> ptr(h->handler_, h);
-
-      // A sub-object of the handler may be the true owner of the memory
-      // associated with the handler. Consequently, a local copy of the handler
-      // is required to ensure that any owning sub-object remains valid until
-      // after we have deallocated the memory here.
-      Handler handler(h->handler_);
-      (void)handler;
-
-      // Free the memory associated with the handler.
-      ptr.reset();
-    }
-
-  private:
-    Handler handler_;
-  };
+  typedef strand_impl* implementation_type;
 
   // Construct a new strand service for the specified io_service.
   explicit strand_service(boost::asio::io_service& io_service)
     : boost::asio::detail::service_base<strand_service>(io_service),
+      io_service_(boost::asio::use_service<io_service_impl>(io_service)),
       mutex_(),
       salt_(0)
   {
@@ -295,37 +88,13 @@ public:
   // Destroy all user-defined handler objects owned by the service.
   void shutdown_service()
   {
-    // Construct a list of all handlers to be destroyed.
+    op_queue<operation> ops;
+
     boost::asio::detail::mutex::scoped_lock lock(mutex_);
-    handler_base* first_handler = 0;
+
     for (std::size_t i = 0; i < num_implementations; ++i)
-    {
       if (strand_impl* impl = implementations_[i].get())
-      {
-        if (impl->current_handler_)
-        {
-          impl->current_handler_->next_ = first_handler;
-          first_handler = impl->current_handler_;
-          impl->current_handler_ = 0;
-        }
-        if (impl->first_waiter_)
-        {
-          impl->last_waiter_->next_ = first_handler;
-          first_handler = impl->first_waiter_;
-          impl->first_waiter_ = 0;
-          impl->last_waiter_ = 0;
-        }
-      }
-    }
-
-    // Destroy all handlers without holding the lock.
-    lock.unlock();
-    while (first_handler)
-    {
-      handler_base* next = first_handler->next_;
-      first_handler->destroy();
-      first_handler = next;
-    }
+        ops.push(impl->queue_);
   }
 
   // Construct a new strand implementation.
@@ -352,45 +121,54 @@ public:
   template <typename Handler>
   void dispatch(implementation_type& impl, Handler handler)
   {
+    // If we are already in the strand then the handler can run immediately.
     if (call_stack<strand_impl>::contains(impl))
     {
+      boost::asio::detail::fenced_block b;
       boost_asio_handler_invoke_helpers::invoke(handler, handler);
+      return;
     }
-    else
+
+    // Allocate and construct an object to wrap the handler.
+    typedef completion_handler<Handler> value_type;
+    typedef handler_alloc_traits<Handler, value_type> alloc_traits;
+    raw_handler_ptr<alloc_traits> raw_ptr(handler);
+    handler_ptr<alloc_traits> ptr(raw_ptr, handler);
+
+    // If we are running inside the io_service, and no other handler is queued
+    // or running, then the handler can run immediately.
+    bool can_dispatch = call_stack<io_service_impl>::contains(&io_service_);
+    impl->mutex_.lock();
+    bool first = (++impl->count_ == 1);
+    if (can_dispatch && first)
     {
-      // Allocate and construct an object to wrap the handler.
-      typedef handler_wrapper<Handler> value_type;
-      typedef handler_alloc_traits<Handler, value_type> alloc_traits;
-      raw_handler_ptr<alloc_traits> raw_ptr(handler);
-      handler_ptr<alloc_traits> ptr(raw_ptr, handler);
-
-      boost::asio::detail::mutex::scoped_lock lock(impl->mutex_);
-
-      if (impl->current_handler_ == 0)
-      {
-        // This handler now has the lock, so can be dispatched immediately.
-        impl->current_handler_ = ptr.release();
-        lock.unlock();
-        this->get_io_service().dispatch(invoke_current_handler(*this, impl));
-      }
-      else
-      {
-        // Another handler already holds the lock, so this handler must join
-        // the list of waiters. The handler will be posted automatically when
-        // its turn comes.
-        if (impl->last_waiter_)
-        {
-          impl->last_waiter_->next_ = ptr.get();
-          impl->last_waiter_ = impl->last_waiter_->next_;
-        }
-        else
-        {
-          impl->first_waiter_ = ptr.get();
-          impl->last_waiter_ = ptr.get();
-        }
-        ptr.release();
-      }
+      // Immediate invocation is allowed.
+      impl->mutex_.unlock();
+
+      // Memory must be releaesed before any upcall is made.
+      ptr.reset();
+
+      // Indicate that this strand is executing on the current thread.
+      call_stack<strand_impl>::context ctx(impl);
+
+      // Ensure the next handler, if any, is scheduled on block exit.
+      on_dispatch_exit on_exit = { &io_service_, impl };
+      (void)on_exit;
+
+      boost::asio::detail::fenced_block b;
+      boost_asio_handler_invoke_helpers::invoke(handler, handler);
+      return;
     }
+
+    // Immediate invocation is not allowed, so enqueue for later.
+    impl->queue_.push(ptr.get());
+    impl->mutex_.unlock();
+    ptr.release();
+
+    // The first handler to be enqueued is responsible for scheduling the
+    // strand.
+    if (first)
+      io_service_.post_immediate_completion(impl);
   }
 
   // Request the io_service to invoke the given handler and return immediately.
@@ -398,40 +176,85 @@ public:
   void post(implementation_type& impl, Handler handler)
   {
     // Allocate and construct an object to wrap the handler.
-    typedef handler_wrapper<Handler> value_type;
+    typedef completion_handler<Handler> value_type;
     typedef handler_alloc_traits<Handler, value_type> alloc_traits;
     raw_handler_ptr<alloc_traits> raw_ptr(handler);
     handler_ptr<alloc_traits> ptr(raw_ptr, handler);
 
-    boost::asio::detail::mutex::scoped_lock lock(impl->mutex_);
+    // Add the handler to the queue.
+    impl->mutex_.lock();
+    bool first = (++impl->count_ == 1);
+    impl->queue_.push(ptr.get());
+    impl->mutex_.unlock();
+    ptr.release();
+
+    // The first handler to be enqueue is responsible for scheduling the strand.
+    if (first)
+      io_service_.post_immediate_completion(impl);
+  }
+
+private:
+  static void do_complete(io_service_impl* owner, operation* base,
+      boost::system::error_code /*ec*/, std::size_t /*bytes_transferred*/)
+  {
+    if (owner)
+    {
+      strand_impl* impl = static_cast<strand_impl*>(base);
+
+      // Get the next handler to be executed.
+      impl->mutex_.lock();
+      operation* o = impl->queue_.front();
+      impl->queue_.pop();
+      impl->mutex_.unlock();
+
+      // Indicate that this strand is executing on the current thread.
+      call_stack<strand_impl>::context ctx(impl);
+
+      // Ensure the next handler, if any, is scheduled on block exit.
+      on_do_complete_exit on_exit = { owner, impl };
+      (void)on_exit;
+
+      o->complete(*owner);
+    }
+  }
+
+  // Helper class to re-post the strand on exit.
+  struct on_do_complete_exit
+  {
+    io_service_impl* owner_;
+    strand_impl* impl_;
 
-    if (impl->current_handler_ == 0)
+    ~on_do_complete_exit()
     {
-      // This handler now has the lock, so can be dispatched immediately.
-      impl->current_handler_ = ptr.release();
-      lock.unlock();
-      this->get_io_service().post(invoke_current_handler(*this, impl));
+      impl_->mutex_.lock();
+      bool more_handlers = (--impl_->count_ > 0);
+      impl_->mutex_.unlock();
+
+      if (more_handlers)
+        owner_->post_immediate_completion(impl_);
     }
-    else
+  };
+
+  // Helper class to re-post the strand on exit.
+  struct on_dispatch_exit
+  {
+    io_service_impl* io_service_;
+    strand_impl* impl_;
+
+    ~on_dispatch_exit()
     {
-      // Another handler already holds the lock, so this handler must join the
-      // list of waiters. The handler will be posted automatically when its turn
-      // comes.
-      if (impl->last_waiter_)
-      {
-        impl->last_waiter_->next_ = ptr.get();
-        impl->last_waiter_ = impl->last_waiter_->next_;
-      }
-      else
-      {
-        impl->first_waiter_ = ptr.get();
-        impl->last_waiter_ = ptr.get();
-      }
-      ptr.release();
+      impl_->mutex_.lock();
+      bool more_handlers = (--impl_->count_ > 0);
+      impl_->mutex_.unlock();
+
+      if (more_handlers)
+        io_service_->post_immediate_completion(impl_);
     }
-  }
+  };
+
+  // The io_service implementation used to post completions.
+  io_service_impl& io_service_;
 
-private:
   // Mutex to protect access to the array of implementations.
   boost::asio::detail::mutex mutex_;