path: root/ace/Reactor.h

/* -*- C++ -*- */
// $Id$

// ============================================================================
//
// = LIBRARY
//    ace
//
// = FILENAME
//    Reactor.h
//
// = AUTHOR
//    Irfan Pyarali
//
// ============================================================================

#ifndef ACE_REACTOR_H
#define ACE_REACTOR_H
#include "ace/pre.h"

class ACE_Reactor_Impl;

// Need the class def for ACE_Handle_Set to compile references to it in
// programs.
#include "ace/Handle_Set.h"

#if !defined (ACE_LACKS_PRAGMA_ONCE)
# pragma once
#endif /* ACE_LACKS_PRAGMA_ONCE */

// Timer Queue is a complicated template class. A simple forward
// declaration will not work
#include "ace/Timer_Queue.h"

// Event_Handler.h contains the definition of ACE_Reactor_Mask
#include "ace/Event_Handler.h"

// We are using 4 or 5 signal classes, we could forward declare
// them.... But Timer_Queue_T.h includes Signal.h, so I don't think
// forward declaration will be useful here
#include "ace/Signal.h"

class ACE_Export ACE_Reactor
{
  // = TITLE
  //     The resposiblility of this class is to forward all methods to
  //     its delegation/implementation class, e.g.,
  //     <ACE_Select_Reactor> or <ACE_WFMO_Reactor>.
public:
  enum
  {
    // = Operations on the "ready" mask and the "dispatch" mask.
    GET_MASK = 1,
    // Retrieve current value of the the "ready" mask or the
    // "dispatch" mask.
    SET_MASK = 2,
    // Set value of bits to new mask (changes the entire mask).
    ADD_MASK = 3,
    // Bitwise "or" the value into the mask (only changes enabled
    // bits).
    CLR_MASK = 4
    // Bitwise "and" the negation of the value out of the mask (only
    // changes enabled bits).
  };

  typedef int (*REACTOR_EVENT_HOOK)(void*);
  // You can add a hook to various run_event methods and the hook will
  // be called after handling every reactor event.  If this function
  // returns 0, run_reactor_event_loop will check for the return value of
  // handle_event.  If it is -1, the the run_reactor_event_loop will return
  // (pre-maturely.)

  static ACE_Reactor *instance (void);
  // Get pointer to a process-wide <ACE_Reactor>.

  static ACE_Reactor *instance (ACE_Reactor *,
                                int delete_reactor = 0);
  // Set pointer to a process-wide <ACE_Reactor> and return existing
  // pointer.  If <delete_reactor> != 0 then we'll delete the Reactor
  // at destruction time.

  static void close_singleton (void);
  // Delete the dynamically allocated Singleton

  // = Singleton reactor event loop management methods.

  // Note that these method ONLY work on the "Singleton Reactor,"
  // i.e., the one returned from <ACE_Reactor::instance>.
  static int run_event_loop (void);
  static int run_alertable_event_loop (void);
  // Run the event loop until the
  // <ACE_Reactor::handle_events/ACE_Reactor::alertable_handle_events>
  // method returns -1 or the <end_event_loop> method is invoked.
  // Note that this method can only be used by the singleton
  // <ACE_Reactor::instance>.  Thus, to run another reactor use
  // <ACE_Reactor::run_reactor_event_loop>.

  static int run_event_loop (ACE_Time_Value &tv);
  static int run_alertable_event_loop (ACE_Time_Value &tv);
  // Run the event loop until the <ACE_Reactor::handle_events> or
  // <ACE_Reactor::alertable_handle_events> methods returns -1, the
  // <end_event_loop> method is invoked, or the <ACE_Time_Value>
  // expires.  Note that this method can only be used by the singleton
  // <ACE_Reactor::instance>.  Thus, to run another reactor use
  // <ACE_Reactor::run_reactor_event_loop>.

  static int end_event_loop (void);
  // Instruct the <ACE_Reactor::instance> to terminate its event loop
  // and notifies the <ACE_Reactor::instance> so that it can wake up
  // and close down gracefully.  Note that this method can only be
  // used by the singleton <ACE_Reactor::instance>.  Thus, to
  // terminate another reactor, use
  // <ACE_Reactor::end_reactor_event_loop>.

  static int event_loop_done (void);
  // Report if the <ACE_Reactor::instance>'s event loop is finished.
  // Note that this method can only be used by the singleton
  // <ACE_Reactor::instance>.  Thus, to check another reactor use
  // <ACE_Reactor::reactor_event_loop_done>.

  static void reset_event_loop (void);
  // Resets the <ACE_Reactor::end_event_loop_> static so that the
  // <run_event_loop> method can be restarted.  Note that this method
  // can only be used by the singleton <ACE_Reactor::instance>.  Thus,
  // to reset another reactor use
  // <ACE_Reactor::reset_reactor_event_loop>.

  static int check_reconfiguration (void *);
  // The singleton reactor is used by the <ACE_Service_Config>.
  // Therefore, we must check for the reconfiguration request and
  // handle it after handling an event.

  // = Reactor event loop management methods.

  // These methods work with an instance of a reactor.
  virtual int run_reactor_event_loop (REACTOR_EVENT_HOOK = 0);
  virtual int run_alertable_reactor_event_loop (REACTOR_EVENT_HOOK = 0);
  // Run the event loop until the
  // <ACE_Reactor::handle_events/ACE_Reactor::alertable_handle_events>
  // method returns -1 or the <end_event_loop> method is invoked.

  virtual int run_reactor_event_loop (ACE_Time_Value &tv,
                                      REACTOR_EVENT_HOOK = 0);
  virtual int run_alertable_reactor_event_loop (ACE_Time_Value &tv,
                                                REACTOR_EVENT_HOOK = 0);
  // Run the event loop until the <ACE_Reactor::handle_events> or
  // <ACE_Reactor::alertable_handle_events> methods returns -1, the
  // <end_event_loop> method is invoked, or the <ACE_Time_Value>
  // expires.

  virtual int end_reactor_event_loop (void);
  // Instruct the <ACE_Reactor::instance> to terminate its event loop
  // and notifies the <ACE_Reactor::instance> so that it can wake up
  // and close down gracefully.

  virtual int reactor_event_loop_done (void);
  // Report if the <ACE_Reactor::instance>'s event loop is finished.

  virtual void reset_reactor_event_loop (void);
  // Resets the <ACE_Reactor::end_event_loop_> static so that the
  // <run_event_loop> method can be restarted.

  ACE_Reactor (ACE_Reactor_Impl *implementation = 0,
               int delete_implementation = 0);
  // Create the Reactor using <implementation>.  The flag
  // <delete_implementation> tells the Reactor whether or not to
  // delete the <implementation> on destruction.

  virtual ~ACE_Reactor (void);
  // Close down and release all resources.

  virtual int open (size_t max_number_of_handles,
                    int restart = 0,
                    ACE_Sig_Handler *signal_handler = 0,
                    ACE_Timer_Queue *timer_queue = 0);
  // Initialize the <ACE_Reactor> to manage <max_number_of_handles>.
  // If <restart> is non-0 then the <ACE_Reactor>'s <handle_events>
  // method will be restarted automatically when <EINTR> occurs.  If
  // <signal_handler> or <timer_queue> are non-0 they are used as the
  // signal handler and timer queue, respectively.

  virtual int set_sig_handler (ACE_Sig_Handler *signal_handler);
  // Use a user specified signal handler instead.

  // = The following method is deprecated.  Use <timer_queue> instead.
  virtual int set_timer_queue (ACE_Timer_Queue *tq);
  // Set a user specified timer queue.

  virtual int timer_queue (ACE_Timer_Queue *tq);
  // Set a user-specified timer queue.
  virtual ACE_Timer_Queue *timer_queue (void) const;
  // Return the current <ACE_Timer_Queue>. 

  virtual int close (void);
  // Close down and release all resources.

  // = Event loop drivers.

  virtual int work_pending (const ACE_Time_Value &max_wait_time =  ACE_Time_Value::zero);
  // Returns non-zero if there are I/O events "ready" for dispatching,
  // but does not actually dispatch the event handlers.  By default,
  // don't block while checking this, i.e., "poll".

  virtual int handle_events (ACE_Time_Value *max_wait_time = 0);
  virtual int alertable_handle_events (ACE_Time_Value *max_wait_time = 0);
  // This event loop driver blocks for up to <max_wait_time> before
  // returning.  It will return earlier if events occur.  Note that
  // <max_wait_time> can be 0, in which case this method blocks
  // indefinitely until events occur.
  //
  // <max_wait_time> is decremented to reflect how much time this call
  // took.  For instance, if a time value of 3 seconds is passed to
  // handle_events and an event occurs after 2 seconds,
  // <max_wait_time> will equal 1 second.  This can be used if an
  // application wishes to handle events for some fixed amount of
  // time.
  //
  // Returns the total number of timers and I/O <ACE_Event_Handler>s
  // that were dispatched, 0 if the <max_wait_time> elapsed without
  // dispatching any handlers, or -1 if an error occurs.
  //
  // The only difference between <alertable_handle_events> and
  // <handle_events> is that in the alertable case, the eventloop will
  // return when the system queues an I/O completion routine or an
  // Asynchronous Procedure Call.

  virtual int handle_events (ACE_Time_Value &max_wait_time);
  virtual int alertable_handle_events (ACE_Time_Value &max_wait_time);
  // This method is just like the one above, except the
  // <max_wait_time> value is a reference and can therefore never be
  // NULL.
  //
  // The only difference between <alertable_handle_events> and
  // <handle_events> is that in the alertable case, the eventloop will
  // return when the system queues an I/O completion routine or an
  // Asynchronous Procedure Call.

  // = Register and remove Handlers.

  virtual int register_handler (ACE_Event_Handler *event_handler,
                                ACE_Reactor_Mask mask);
  // Register <event_handler> with <mask>.  The I/O handle will always
  // come from <get_handle> on the <event_handler>.

  virtual int register_handler (ACE_HANDLE io_handle,
                                ACE_Event_Handler *event_handler,
                                ACE_Reactor_Mask mask);
  // Register <event_handler> with <mask>.  The I/O handle is provided
  // through the <io_handle> parameter.

#if defined (ACE_WIN32)
  virtual int register_handler (ACE_Event_Handler *event_handler,
                                ACE_HANDLE event_handle = ACE_INVALID_HANDLE);
  // Register an <event_handler> that will be notified when
  // <event_handle> is signaled.  Since no event mask is passed
  // through this interface, it is assumed that the <event_handle>
  // being passed in is an event handle and not an I/O handle.
  //
  // Originally this interface was available for all platforms, but
  // because ACE_HANDLE is an int on non-Win32 platforms, compilers
  // are not able to tell the difference between
  // register_handler(ACE_Event_Handler*,ACE_Reactor_Mask) and
  // register_handler(ACE_Event_Handler*,ACE_HANDLE). Therefore, we
  // have restricted this method to Win32 only.
#endif /* ACE_WIN32 */

  virtual int register_handler (ACE_HANDLE event_handle,
                                ACE_HANDLE io_handle,
                                ACE_Event_Handler *event_handler,
                                ACE_Reactor_Mask mask);
  // Register an <event_handler> that will be notified when
  // <event_handle> is signaled.  <mask> specifies the network events
  // that the <event_handler> is interested in.

  virtual int register_handler (const ACE_Handle_Set &handles,
                                ACE_Event_Handler *event_handler,
                                ACE_Reactor_Mask mask);
  // Register <event_handler> with all the <handles> in the <Handle_Set>.

  virtual int register_handler (int signum,
                                ACE_Event_Handler *new_sh,
                                ACE_Sig_Action *new_disp = 0,
                                ACE_Event_Handler **old_sh = 0,
                                ACE_Sig_Action *old_disp = 0);
  // Register <new_sh> to handle the signal <signum> using the
  // <new_disp>.  Returns the <old_sh> that was previously registered
  // (if any), along with the <old_disp> of the signal handler.

  virtual int register_handler (const ACE_Sig_Set &sigset,
                                ACE_Event_Handler *new_sh,
                                ACE_Sig_Action *new_disp = 0);
  // Registers <new_sh> to handle a set of signals <sigset> using the
  // <new_disp>.

  virtual int remove_handler (ACE_Event_Handler *event_handler,
                              ACE_Reactor_Mask mask);
  // Removes <event_handler>.  Note that the I/O handle will be
  // obtained using <get_handle> method of <event_handler> .  If
  // <mask> == <ACE_Event_Handler::DONT_CALL> then the <handle_close>
  // method of the <event_handler> is not invoked.

  virtual int remove_handler (ACE_HANDLE handle,
                              ACE_Reactor_Mask mask);
  // Removes <handle>.  If <mask> == <ACE_Event_Handler::DONT_CALL>
  // then the <handle_close> method of the associated <event_handler>
  // is not invoked.

  virtual int remove_handler (const ACE_Handle_Set &handle_set,
                              ACE_Reactor_Mask mask);
  // Removes all handles in <handle_set>.  If <mask> ==
  // <ACE_Event_Handler::DONT_CALL> then the <handle_close> method of
  // the associated <event_handler>s is not invoked.

  virtual int remove_handler (int signum,
                              ACE_Sig_Action *new_disp,
                              ACE_Sig_Action *old_disp = 0,
                              int sigkey = -1);
  // Remove the ACE_Event_Handler currently associated with <signum>.
  // Install the new disposition (if given) and return the previous
  // disposition (if desired by the caller).  Returns 0 on success and
  // -1 if <signum> is invalid.

  virtual int remove_handler (const ACE_Sig_Set &sigset);
  // Calls <remove_handler> for every signal in <sigset>.

  // = Suspend and resume Handlers.

  virtual int suspend_handler (ACE_Event_Handler *event_handler);
  // Suspend <event_handler> temporarily.  Use
  // <ACE_Event_Handler::get_handle> to get the handle.

  virtual int suspend_handler (ACE_HANDLE handle);
  // Suspend <handle> temporarily.

  virtual int suspend_handler (const ACE_Handle_Set &handles);
  // Suspend all <handles> in handle set temporarily.

  virtual int suspend_handlers (void);
  // Suspend all <handles> temporarily.

  virtual int resume_handler (ACE_Event_Handler *event_handler);
  // Resume <event_handler>. Use <ACE_Event_Handler::get_handle> to
  // get the handle.

  virtual int resume_handler (ACE_HANDLE handle);
  // Resume <handle>.

  virtual int resume_handler (const ACE_Handle_Set &handles);
  // Resume all <handles> in handle set.

  virtual int resume_handlers (void);
  // Resume all <handles>.

  // = Timer management.

  virtual long schedule_timer (ACE_Event_Handler *event_handler,
                               const void *arg,
                               const ACE_Time_Value &delta,
                               const ACE_Time_Value &interval = ACE_Time_Value::zero);
  // Schedule an <event_handler> that will expire after <delay> amount
  // of time, which is specified as relative time to the current
  // <gettimeofday>.  If it expires then <arg> is passed in as the
  // value to the <event_handler>'s <handle_timeout> callback method.
  // If <interval> is != to <ACE_Time_Value::zero> then it is used to
  // reschedule the <event_handler> automatically, also specified
  // using relative time.  This method returns a <timer_id> that
  // uniquely identifies the <event_handler> in an internal list.
  // This <timer_id> can be used to cancel an <event_handler> before
  // it expires.  The cancellation ensures that <timer_ids> are unique
  // up to values of greater than 2 billion timers.  As long as timers
  // don't stay around longer than this there should be no problems
  // with accidentally deleting the wrong timer.  Returns -1 on
  // failure (which is guaranteed never to be a valid <timer_id>.

  virtual int reset_timer_interval (long timer_id, 
                                    const ACE_Time_Value &interval);
  // Resets the interval of the timer represented by <timer_id> to
  // <interval>, which is specified in relative time to the current
  // <gettimeofday>.  If <interval> is equal to
  // <ACE_Time_Value::zero>, the timer will become a non-rescheduling
  // timer.  Returns 0 if successful, -1 if not.

  virtual int cancel_timer (ACE_Event_Handler *event_handler,
                            int dont_call_handle_close = 1);
  // Cancel all <Event_Handler>s that match the address of
  // <event_handler>.  Returns number of handlers cancelled.

  virtual int cancel_timer (long timer_id,
                            const void **arg = 0,
                            int dont_call_handle_close = 1);
  // Cancel the single <Event_Handler> that matches the <timer_id>
  // value, which was returned from the schedule method.  If arg is
  // non-NULL then it will be set to point to the ``magic cookie''
  // argument passed in when the Event_Handler was registered.  This
  // makes it possible to free up the memory and avoid memory leaks.
  // Returns 1 if cancellation succeeded and 0 if the <timer_id>
  // wasn't found.

  // = High-level Event_Handler scheduling operations

  virtual int schedule_wakeup (ACE_Event_Handler *event_handler,
                               ACE_Reactor_Mask masks_to_be_added);
  // Add <masks_to_be_added> to the <event_handler>'s entry.
  // <event_handler> must already have been registered.

  virtual int schedule_wakeup (ACE_HANDLE handle,
                               ACE_Reactor_Mask masks_to_be_added);
  // Add <masks_to_be_added> to the <handle>'s entry.  <event_handler>
  // associated with <handle> must already have been registered.

  virtual int cancel_wakeup (ACE_Event_Handler *event_handler,
                             ACE_Reactor_Mask masks_to_be_cleared);
  // Clear <masks_to_be_cleared> from the <event_handler>'s entry.

  virtual int cancel_wakeup (ACE_HANDLE handle,
                             ACE_Reactor_Mask masks_to_be_cleared);
  // Clear <masks_to_be_cleared> from the <handle>'s entry.

  // = Notification methods.

  virtual int notify (ACE_Event_Handler *event_handler = 0,
                      ACE_Reactor_Mask mask = ACE_Event_Handler::EXCEPT_MASK,
                      ACE_Time_Value *tv = 0);
  // Notify <event_handler> of <mask> event.  The <ACE_Time_Value>
  // indicates how long to blocking trying to notify.  If <timeout> ==
  // 0, the caller will block until action is possible, else will wait
  // until the relative time specified in <timeout> elapses).

  virtual void max_notify_iterations (int iterations);
  // Set the maximum number of times that ACE_Reactor will
  // iterate and dispatch the <ACE_Event_Handlers> that are passed in
  // via the notify queue before breaking out of its
  // <ACE_Message_Queue::dequeue> loop.  By default, this is set to
  // -1, which means "iterate until the queue is empty."  Setting this
  // to a value like "1 or 2" will increase "fairness" (and thus
  // prevent starvation) at the expense of slightly higher dispatching
  // overhead.

  virtual int max_notify_iterations (void);
  // Get the maximum number of times that the ACE_Reactor will
  // iterate and dispatch the <ACE_Event_Handlers> that are passed in
  // via the notify queue before breaking out of its
  // <ACE_Message_Queue::dequeue> loop.

  // = Assorted helper methods.
  
  virtual int handler (ACE_HANDLE handle,
                       ACE_Reactor_Mask mask,
                       ACE_Event_Handler **event_handler = 0);
  // Check to see if <handle> is associated with a valid Event_Handler
  // bound to <mask>.  Return the <event_handler> associated with this
  // <handler> if <event_handler> != 0.

  virtual int handler (int signum,
                       ACE_Event_Handler **event_handler = 0);
  // Check to see if <signum> is associated with a valid Event_Handler
  // bound to a signal.  Return the <event_handler> associated with
  // this <handler> if <event_handler> != 0.

  virtual int initialized (void);
  // Returns true if Reactor has been successfully initialized, else
  // false.

  virtual size_t size (void);
  // Returns the current size of the Reactor's internal descriptor
  // table.

  virtual ACE_Lock &lock (void);
  // Returns a reference to the Reactor's internal lock.

  virtual void wakeup_all_threads (void);
  // Wake up all threads in waiting in the event loop

  virtual int owner (ACE_thread_t new_owner,
                     ACE_thread_t *old_owner = 0);
  // Transfers ownership of Reactor to the <new_owner>.

  virtual int owner (ACE_thread_t *owner);
  // Return the ID of the "owner" thread.

  virtual void requeue_position (int position);
  // Set position of the owner thread.

  virtual int requeue_position (void);
  // Get position of the owner thread.

  virtual int restart (void);
  // Get the existing restart value.
  
  virtual int restart (int r);
  // Set a new value for restart and return the original value.

  // = Low-level wait_set mask manipulation methods.

  virtual int mask_ops (ACE_Event_Handler *event_handler,
                        ACE_Reactor_Mask mask,
                        int ops);
  // GET/SET/ADD/CLR the dispatch mask "bit" bound with the
  // <event_handler> and <mask>.

  virtual int mask_ops (ACE_HANDLE handle,
                        ACE_Reactor_Mask mask,
                        int ops);
  // GET/SET/ADD/CLR the dispatch MASK "bit" bound with the <handle>
  // and <mask>.

  // = Low-level ready_set mask manipulation methods.
  virtual int ready_ops (ACE_Event_Handler *event_handler,
                         ACE_Reactor_Mask mask,
                         int ops);
  // GET/SET/ADD/CLR the ready "bit" bound with the <event_handler>
  // and <mask>.

  virtual int ready_ops (ACE_HANDLE handle,
                         ACE_Reactor_Mask mask,
                         int ops);
  // GET/SET/ADD/CLR the ready "bit" bound with the <handle> and <mask>.

  virtual ACE_Reactor_Impl *implementation (void);
  // Get the implementation class

  virtual int current_info (ACE_HANDLE handle,
                            size_t &msg_size);
  // Returns 0, if the size of the current message has been put in
  // <size> returns -1, if not.  ACE_HANDLE allows the reactor to
  // check if the caller is valid.  Used for CLASSIX Reactor
  // implementation.

  virtual int uses_event_associations (void);
  // Return 1 if we any event associations were made by the reactor
  // for the handles that it waits on, 0 otherwise.

  ACE_ALLOC_HOOK_DECLARE;
  // Declare the dynamic allocation hooks.

  void dump (void) const;
  // Dump the state of the object.

protected:
  virtual void implementation (ACE_Reactor_Impl *implementation);
  // Set the implementation class.

  ACE_Reactor_Impl *implementation_;
  // Delegation/implementation class that all methods will be
  // forwarded to.

  int delete_implementation_;
  // Flag used to indicate whether we are responsible for cleaning up
  // the implementation instance

  static ACE_Reactor *reactor_;
  // Pointer to a process-wide <ACE_Reactor> singleton.

  static int delete_reactor_;
  // Must delete the <reactor_> singleton if non-0.

  ACE_Reactor (const ACE_Reactor &);
  ACE_Reactor &operator = (const ACE_Reactor &);
  // Deny access since member-wise won't work...
};

#if defined (__ACE_INLINE__)
#include "ace/Reactor.i"
#endif /* __ACE_INLINE__ */

#include "ace/post.h"
#endif /* ACE_REACTOR_H */