Imported existing code

libraries/include/boost/asio/detail/reactor_op_queue.hpp

@@ -0,0 +1,456 @@
+//
+// reactor_op_queue.hpp
+// ~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2008 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef BOOST_ASIO_DETAIL_REACTOR_OP_QUEUE_HPP
+#define BOOST_ASIO_DETAIL_REACTOR_OP_QUEUE_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include <boost/asio/detail/push_options.hpp>
+
+#include <boost/asio/detail/push_options.hpp>
+#include <memory>
+#include <boost/asio/detail/pop_options.hpp>
+
+#include <boost/asio/error.hpp>
+#include <boost/asio/detail/handler_alloc_helpers.hpp>
+#include <boost/asio/detail/hash_map.hpp>
+#include <boost/asio/detail/noncopyable.hpp>
+
+namespace boost {
+namespace asio {
+namespace detail {
+
+template <typename Descriptor>
+class reactor_op_queue
+  : private noncopyable
+{
+public:
+  // Constructor.
+  reactor_op_queue()
+    : operations_(),
+      cancelled_operations_(0),
+      complete_operations_(0)
+  {
+  }
+
+  // Add a new operation to the queue. Returns true if this is the only
+  // operation for the given descriptor, in which case the reactor's event
+  // demultiplexing function call may need to be interrupted and restarted.
+  template <typename Operation>
+  bool enqueue_operation(Descriptor descriptor, Operation operation)
+  {
+    // Allocate and construct an object to wrap the handler.
+    typedef handler_alloc_traits<Operation, op<Operation> > alloc_traits;
+    raw_handler_ptr<alloc_traits> raw_ptr(operation);
+    handler_ptr<alloc_traits> ptr(raw_ptr, descriptor, operation);
+
+    typedef typename operation_map::iterator iterator;
+    typedef typename operation_map::value_type value_type;
+    std::pair<iterator, bool> entry =
+      operations_.insert(value_type(descriptor, ptr.get()));
+    if (entry.second)
+    {
+      ptr.release();
+      return true;
+    }
+
+    op_base* current_op = entry.first->second;
+    while (current_op->next_)
+      current_op = current_op->next_;
+    current_op->next_ = ptr.release();
+
+    return false;
+  }
+
+  // Cancel all operations associated with the descriptor. Any operations
+  // pending for the descriptor will be notified that they have been cancelled
+  // next time perform_cancellations is called. Returns true if any operations
+  // were cancelled, in which case the reactor's event demultiplexing function
+  // may need to be interrupted and restarted.
+  bool cancel_operations(Descriptor descriptor)
+  {
+    typename operation_map::iterator i = operations_.find(descriptor);
+    if (i != operations_.end())
+    {
+      op_base* last_op = i->second;
+      while (last_op->next_)
+        last_op = last_op->next_;
+      last_op->next_ = cancelled_operations_;
+      cancelled_operations_ = i->second;
+      operations_.erase(i);
+      return true;
+    }
+
+    return false;
+  }
+
+  // Whether there are no operations in the queue.
+  bool empty() const
+  {
+    return operations_.empty();
+  }
+
+  // Determine whether there are any operations associated with the descriptor.
+  bool has_operation(Descriptor descriptor) const
+  {
+    return operations_.find(descriptor) != operations_.end();
+  }
+
+  // Perform the first operation corresponding to the descriptor. Returns true
+  // if there are more operations queued for the descriptor.
+  bool perform_operation(Descriptor descriptor,
+      const boost::system::error_code& result)
+  {
+    typename operation_map::iterator i = operations_.find(descriptor);
+    if (i != operations_.end())
+    {
+      op_base* this_op = i->second;
+      i->second = this_op->next_;
+      this_op->next_ = complete_operations_;
+      complete_operations_ = this_op;
+      bool done = this_op->perform(result);
+      if (done)
+      {
+        // Operation has finished.
+        if (i->second)
+        {
+          return true;
+        }
+        else
+        {
+          operations_.erase(i);
+          return false;
+        }
+      }
+      else
+      {
+        // Operation wants to be called again. Leave it at the front of the
+        // queue for this descriptor, and remove from the completed list.
+        complete_operations_ = this_op->next_;
+        this_op->next_ = i->second;
+        i->second = this_op;
+        return true;
+      }
+    }
+    return false;
+  }
+
+  // Perform all operations corresponding to the descriptor.
+  void perform_all_operations(Descriptor descriptor,
+      const boost::system::error_code& result)
+  {
+    typename operation_map::iterator i = operations_.find(descriptor);
+    if (i != operations_.end())
+    {
+      while (i->second)
+      {
+        op_base* this_op = i->second;
+        i->second = this_op->next_;
+        this_op->next_ = complete_operations_;
+        complete_operations_ = this_op;
+        bool done = this_op->perform(result);
+        if (!done)
+        {
+          // Operation has not finished yet, so leave at front of queue, and
+          // remove from the completed list.
+          complete_operations_ = this_op->next_;
+          this_op->next_ = i->second;
+          i->second = this_op;
+          return;
+        }
+      }
+      operations_.erase(i);
+    }
+  }
+
+  // Fill a descriptor set with the descriptors corresponding to each active
+  // operation.
+  template <typename Descriptor_Set>
+  void get_descriptors(Descriptor_Set& descriptors)
+  {
+    typename operation_map::iterator i = operations_.begin();
+    while (i != operations_.end())
+    {
+      Descriptor descriptor = i->first;
+      ++i;
+      if (!descriptors.set(descriptor))
+      {
+        boost::system::error_code ec(error::fd_set_failure);
+        perform_all_operations(descriptor, ec);
+      }
+    }
+  }
+
+  // Perform the operations corresponding to the ready file descriptors
+  // contained in the given descriptor set.
+  template <typename Descriptor_Set>
+  void perform_operations_for_descriptors(const Descriptor_Set& descriptors,
+      const boost::system::error_code& result)
+  {
+    typename operation_map::iterator i = operations_.begin();
+    while (i != operations_.end())
+    {
+      typename operation_map::iterator op_iter = i++;
+      if (descriptors.is_set(op_iter->first))
+      {
+        op_base* this_op = op_iter->second;
+        op_iter->second = this_op->next_;
+        this_op->next_ = complete_operations_;
+        complete_operations_ = this_op;
+        bool done = this_op->perform(result);
+        if (done)
+        {
+          if (!op_iter->second)
+            operations_.erase(op_iter);
+        }
+        else
+        {
+          // Operation has not finished yet, so leave at front of queue, and
+          // remove from the completed list.
+          complete_operations_ = this_op->next_;
+          this_op->next_ = op_iter->second;
+          op_iter->second = this_op;
+        }
+      }
+    }
+  }
+
+  // Perform any pending cancels for operations.
+  void perform_cancellations()
+  {
+    while (cancelled_operations_)
+    {
+      op_base* this_op = cancelled_operations_;
+      cancelled_operations_ = this_op->next_;
+      this_op->next_ = complete_operations_;
+      complete_operations_ = this_op;
+      this_op->perform(boost::asio::error::operation_aborted);
+    }
+  }
+
+  // Complete all operations that are waiting to be completed.
+  void complete_operations()
+  {
+    while (complete_operations_)
+    {
+      op_base* next_op = complete_operations_->next_;
+      complete_operations_->next_ = 0;
+      complete_operations_->complete();
+      complete_operations_ = next_op;
+    }
+  }
+
+  // Destroy all operations owned by the queue.
+  void destroy_operations()
+  {
+    while (cancelled_operations_)
+    {
+      op_base* next_op = cancelled_operations_->next_;
+      cancelled_operations_->next_ = 0;
+      cancelled_operations_->destroy();
+      cancelled_operations_ = next_op;
+    }
+
+    while (complete_operations_)
+    {
+      op_base* next_op = complete_operations_->next_;
+      complete_operations_->next_ = 0;
+      complete_operations_->destroy();
+      complete_operations_ = next_op;
+    }
+
+    typename operation_map::iterator i = operations_.begin();
+    while (i != operations_.end())
+    {
+      typename operation_map::iterator op_iter = i++;
+      op_base* curr_op = op_iter->second;
+      operations_.erase(op_iter);
+      while (curr_op)
+      {
+        op_base* next_op = curr_op->next_;
+        curr_op->next_ = 0;
+        curr_op->destroy();
+        curr_op = next_op;
+      }
+    }
+  }
+
+private:
+  // Base class for reactor operations. A function pointer is used instead of
+  // virtual functions to avoid the associated overhead.
+  class op_base
+  {
+  public:
+    // Get the descriptor associated with the operation.
+    Descriptor descriptor() const
+    {
+      return descriptor_;
+    }
+
+    // Perform the operation.
+    bool perform(const boost::system::error_code& result)
+    {
+      result_ = result;
+      return perform_func_(this, result_, bytes_transferred_);
+    }
+
+    // Destroy the operation and post the handler.
+    void complete()
+    {
+      complete_func_(this, result_, bytes_transferred_);
+    }
+
+    // Destroy the operation.
+    void destroy()
+    {
+      destroy_func_(this);
+    }
+
+  protected:
+    typedef bool (*perform_func_type)(op_base*,
+        boost::system::error_code&, std::size_t&);
+    typedef void (*complete_func_type)(op_base*,
+        const boost::system::error_code&, std::size_t);
+    typedef void (*destroy_func_type)(op_base*);
+
+    // Construct an operation for the given descriptor.
+    op_base(perform_func_type perform_func, complete_func_type complete_func,
+        destroy_func_type destroy_func, Descriptor descriptor)
+      : perform_func_(perform_func),
+        complete_func_(complete_func),
+        destroy_func_(destroy_func),
+        descriptor_(descriptor),
+        result_(),
+        bytes_transferred_(0),
+        next_(0)
+    {
+    }
+
+    // Prevent deletion through this type.
+    ~op_base()
+    {
+    }
+
+  private:
+    friend class reactor_op_queue<Descriptor>;
+
+    // The function to be called to perform the operation.
+    perform_func_type perform_func_;
+
+    // The function to be called to delete the operation and post the handler.
+    complete_func_type complete_func_;
+
+    // The function to be called to delete the operation.
+    destroy_func_type destroy_func_;
+
+    // The descriptor associated with the operation.
+    Descriptor descriptor_;
+
+    // The result of the operation.
+    boost::system::error_code result_;
+
+    // The number of bytes transferred in the operation.
+    std::size_t bytes_transferred_;
+
+    // The next operation for the same file descriptor.
+    op_base* next_;
+  };
+
+  // Adaptor class template for operations.
+  template <typename Operation>
+  class op
+    : public op_base
+  {
+  public:
+    // Constructor.
+    op(Descriptor descriptor, Operation operation)
+      : op_base(&op<Operation>::do_perform, &op<Operation>::do_complete,
+          &op<Operation>::do_destroy, descriptor),
+        operation_(operation)
+    {
+    }
+
+    // Perform the operation.
+    static bool do_perform(op_base* base,
+        boost::system::error_code& result, std::size_t& bytes_transferred)
+    {
+      return static_cast<op<Operation>*>(base)->operation_.perform(
+          result, bytes_transferred);
+    }
+
+    // Destroy the operation and post the handler.
+    static void do_complete(op_base* base,
+        const boost::system::error_code& result, std::size_t bytes_transferred)
+    {
+      // Take ownership of the operation object.
+      typedef op<Operation> this_type;
+      this_type* this_op(static_cast<this_type*>(base));
+      typedef handler_alloc_traits<Operation, this_type> alloc_traits;
+      handler_ptr<alloc_traits> ptr(this_op->operation_, this_op);
+
+      // Make a copy of the error_code and the operation so that the memory can
+      // be deallocated before the upcall is made.
+      boost::system::error_code ec(result);
+      Operation operation(this_op->operation_);
+
+      // Free the memory associated with the operation.
+      ptr.reset();
+
+      // Make the upcall.
+      operation.complete(ec, bytes_transferred);
+    }
+
+    // Destroy the operation.
+    static void do_destroy(op_base* base)
+    {
+      // Take ownership of the operation object.
+      typedef op<Operation> this_type;
+      this_type* this_op(static_cast<this_type*>(base));
+      typedef handler_alloc_traits<Operation, this_type> alloc_traits;
+      handler_ptr<alloc_traits> ptr(this_op->operation_, this_op);
+
+      // A sub-object of the operation may be the true owner of the memory
+      // associated with the operation. Consequently, a local copy of the
+      // operation is required to ensure that any owning sub-object remains
+      // valid until after we have deallocated the memory here.
+      Operation operation(this_op->operation_);
+      (void)operation;
+
+      // Free the memory associated with the operation.
+      ptr.reset();
+    }
+
+  private:
+    Operation operation_;
+  };
+
+  // The type for a map of operations.
+  typedef hash_map<Descriptor, op_base*> operation_map;
+
+  // The operations that are currently executing asynchronously.
+  operation_map operations_;
+
+  // The list of operations that have been cancelled.
+  op_base* cancelled_operations_;
+
+  // The list of operations waiting to be completed.
+  op_base* complete_operations_;
+};
+
+} // namespace detail
+} // namespace asio
+} // namespace boost
+
+#include <boost/asio/detail/pop_options.hpp>
+
+#endif // BOOST_ASIO_DETAIL_REACTOR_OP_QUEUE_HPP