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Diffstat (limited to 'ACE/ace/Dev_Poll_Reactor.h')
| -rw-r--r-- | ACE/ace/Dev_Poll_Reactor.h | 1281 |
1 files changed, 1281 insertions, 0 deletions
diff --git a/ACE/ace/Dev_Poll_Reactor.h b/ACE/ace/Dev_Poll_Reactor.h new file mode 100644 index 00000000000..78b0949b7d3 --- /dev/null +++ b/ACE/ace/Dev_Poll_Reactor.h @@ -0,0 +1,1281 @@ +// -*- C++ -*- + +// ========================================================================= +/** + * @file Dev_Poll_Reactor.h + * + * $Id$ + * + * @em Experimental @c /dev/poll (or Linux @c sys_epoll) based + * Reactor implementation. + * + * @author Ossama Othman <ossama@dre.vanderbilt.edu> + */ +// ========================================================================= + + +#ifndef ACE_DEV_POLL_REACTOR_H +#define ACE_DEV_POLL_REACTOR_H + +#include /**/ "ace/pre.h" + +#include "ace/ACE_export.h" + +#if !defined (ACE_LACKS_PRAGMA_ONCE) +# pragma once +#endif /* ACE_LACKS_PRAGMA_ONCE */ + +#if defined (ACE_HAS_EVENT_POLL) +// The sys_epoll interface was introduced in Linux kernel 2.5.45. +// Don't support backported versions since they appear to be buggy. +// The obsolete ioctl()-based interface is no longer supported. +#if 0 +// linux/version.h may not be accurate. It's not for Fedora Core 2... +# include /**/ <linux/version.h> +# if LINUX_VERSION_CODE < KERNEL_VERSION (2,5,45) +# undef ACE_HAS_EVENT_POLL +# error Disabling Linux epoll support. Kernel used in C library is too old. +# error Linux kernel 2.5.45 or better is required. +# endif /* LINUX_VERSION_CODE < KERNEL_VERSION (2,5,45) */ +#endif /* ACE_HAS_EVENT_POLL */ +#endif + +#if defined (ACE_HAS_EVENT_POLL) && defined (ACE_HAS_DEV_POLL) +# error ACE_HAS_EVENT_POLL and ACE_HAS_DEV_POLL are mutually exclusive. +#endif /* ACE_HAS_EVENT_POLL && defined ACE_HAS_DEV_POLL */ + + +#if defined (ACE_HAS_EVENT_POLL) || defined (ACE_HAS_DEV_POLL) + +#include "ace/Pipe.h" +#include "ace/Lock_Adapter_T.h" +#include "ace/Reactor_Impl.h" +#include "ace/Reactor_Token_T.h" +#include "ace/Token.h" + +#if defined (ACE_HAS_REACTOR_NOTIFICATION_QUEUE) +# include "ace/Unbounded_Queue.h" +#endif /* ACE_HAS_REACTOR_NOTIFICATION_QUEUE */ + +#if defined (ACE_HAS_DEV_POLL) +struct pollfd; +#elif defined (ACE_HAS_EVENT_POLL) +struct epoll_event; +#endif + +ACE_BEGIN_VERSIONED_NAMESPACE_DECL + +// Forward declarations +class ACE_Sig_Handler; +class ACE_Dev_Poll_Reactor; + +/** + * @class ACE_Dev_Poll_Event_Tuple + * + * @brief Class that associates specific event mask with a given event + * handler. + * + * This class merely provides a means to associate an event mask + * with an event handler. Such an association is needed since it is + * not possible to retrieve the event mask from the "interest set" + * stored in the `/dev/poll' or `/dev/epoll' driver. Without this + * external association, it would not be possible keep track of the + * event mask for a given event handler when suspending it or resuming + * it. + * + * @note An ACE_Handle_Set is not used since the number of handles may + * exceed its capacity (ACE_DEFAULT_SELECT_REACTOR_SIZE). + */ +class ACE_Dev_Poll_Event_Tuple +{ +public: + + /// Constructor. + ACE_Dev_Poll_Event_Tuple (void); + +public: + + /// The event handler. + ACE_Event_Handler *event_handler; + + /// The event mask for the above event handler. + ACE_Reactor_Mask mask; + + /// Flag that states whether or not the event handler is suspended. + char suspended; +}; + +// --------------------------------------------------------------------- + +#if 0 +/** + * @class ACE_Dev_Poll_Ready_Set + * + * @brief Class that contains the list of "ready" file descriptors. + * + * This class points to an array of pollfd structures corresponding to + * "ready" file descriptors, such as those corresponding to event + * handlers that request an additional callback after being initially + * dispatched (i.e. return a value greater than zero). + * @par + * The idea is to store the "ready" set in an existing area of memory + * that already contains pollfd instances. Doing so is safe since the + * "ready" set is dispatched before polling for additional events, + * thus avoiding being potentially overwritten during the event poll. + * @par + * When the "ready" set is dispatched, all that needs to be done is to + * iterate over the contents of the array. There is no need to "walk" + * the array in search of ready file descriptors since the array by + * design only contains ready file descriptors. As such, this + * implementation of a ready set is much more efficient in the + * presence of a large number of file descriptors in terms of both + * time and space than the one used in the Select_Reactor, for + * example. + */ +class ACE_Dev_Poll_Ready_Set +{ +public: + + /// Constructor. + ACE_Dev_Poll_Ready_Set (void); + +public: + + /// The array containing the pollfd structures corresponding to the + /// "ready" file descriptors. + struct pollfd *pfds; + + /// The number of "ready" file descriptors in the above array. + int nfds; + +}; +#endif /* 0 */ + +// --------------------------------------------------------------------- + +/** + * @class ACE_Dev_Poll_Reactor_Notify + * + * @brief Event handler used for unblocking the ACE_Dev_Poll_Reactor + * from its event loop. + * + * This event handler is used internally by the ACE_Dev_Poll_Reactor + * as a means to allow a thread other then the one running the event + * loop to unblock the event loop. + */ +class ACE_Dev_Poll_Reactor_Notify : public ACE_Reactor_Notify +{ +public: + + /// Constructor + ACE_Dev_Poll_Reactor_Notify (void); + + /** + * @name Initialization and Termination Methods + * + * Methods called when initializing and terminating this event + * handler. + */ + virtual int open (ACE_Reactor_Impl *, + ACE_Timer_Queue *timer_queue = 0, + int disable_notify = 0); + virtual int close (void); + + /** + * Called by a thread when it wants to unblock the Reactor_Impl. + * This wakes up the Reactor_Impl if currently blocked. Pass over + * both the Event_Handler and the mask to allow the caller to + * dictate which Event_Handler method the Reactor_Impl will + * invoke. The ACE_Time_Value indicates how long to block + * trying to notify the Reactor_Impl. If timeout == 0, the + * caller will block until action is possible, else will wait until + * the relative time specified in *timeout elapses). + */ + virtual int notify (ACE_Event_Handler *eh = 0, + ACE_Reactor_Mask mask = ACE_Event_Handler::EXCEPT_MASK, + ACE_Time_Value *timeout = 0); + + /// Unimplemented method required by pure virtual method in abstract + /// base class. + /** + * This method's interface is not very compatibile with this + * Reactor's design. It's not clear why this method is pure virtual + * either. + */ + virtual int dispatch_notifications (int &number_of_active_handles, + ACE_Handle_Set &rd_mask); + + /// Returns the ACE_HANDLE of the notify pipe on which the reactor + /// is listening for notifications so that other threads can unblock + /// the Reactor_Impl. + virtual ACE_HANDLE notify_handle (void); + + /// Verify whether the buffer has dispatchable info or not. + virtual int is_dispatchable (ACE_Notification_Buffer &buffer); + + /// Handle one notify call represented in @a buffer. This could be + /// because of a thread trying to unblock the Reactor_Impl. + virtual int dispatch_notify (ACE_Notification_Buffer &buffer); + + /// Read one notify call on the handle into @a buffer. + /// This could be because of a thread trying to unblock the Reactor_Impl. + virtual int read_notify_pipe (ACE_HANDLE handle, + ACE_Notification_Buffer &buffer); + + /// Called back by the ACE_Dev_Poll_Reactor when a thread wants to + /// unblock us. + virtual int handle_input (ACE_HANDLE handle); + + /** + * Set the maximum number of times that the handle_input method + * will iterate and dispatch the ACE_Event_Handlers that are + * passed in via the notify queue before breaking out of the event + * 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 void max_notify_iterations (int); + + /** + * Get the maximum number of times that the handle_input method + * will iterate and dispatch the ACE_Event_Handlers that are + * passed in via the notify queue before breaking out of its event + * loop. + */ + virtual int max_notify_iterations (void); + + /** + * Purge any notifications pending in this reactor for the specified + * ACE_Event_Handler object. Returns the number of notifications + * purged. Returns -1 on error. + */ + virtual int purge_pending_notifications ( + ACE_Event_Handler * = 0, + ACE_Reactor_Mask = ACE_Event_Handler::ALL_EVENTS_MASK); + + /// Dump the state of an object. + virtual void dump (void) const; + +protected: + + /** + * Keep a back pointer to the ACE_Dev_Poll_Reactor. If this value + * if NULL then the ACE_Dev_Poll_Reactor has been initialized with + * disable_notify_pipe. + */ + ACE_Dev_Poll_Reactor *dp_reactor_; + + /** + * Contains the ACE_HANDLE the ACE_Dev_Poll_Reactor is listening + * on, as well as the ACE_HANDLE that threads wanting the attention + * of the ACE_Dev_Poll_Reactor will write to. + */ + ACE_Pipe notification_pipe_; + + /** + * Keeps track of the maximum number of times that the + * ACE_Dev_Poll_Reactor_Notify::handle_input method will iterate and + * dispatch the ACE_Event_Handlers that are passed in via the + * notify pipe before breaking out of its recv loop. By default, + * this is set to -1, which means "iterate until the pipe is empty." + */ + int max_notify_iterations_; + +#if defined (ACE_HAS_REACTOR_NOTIFICATION_QUEUE) + /** + * @name Reactor Notification Attributes + * + * This configuration queues up notifications in separate buffers + * that are in user-space, rather than stored in a pipe in the OS + * kernel. The kernel-level notifications are used only to trigger + * the Reactor to check its notification queue. This enables many + * more notifications to be stored than would otherwise be the + * case. + */ + //@{ + + /// ACE_Notification_Buffers are allocated in chunks. Each time a chunk is + /// allocated, the chunk is added to alloc_queue_ so it can be freed later. + /// Each individual ACE_Notification_Buffer is added to the free_queue_ + /// when it's free. Those in use for queued notifications are placed on the + /// notify_queue_. + ACE_Unbounded_Queue <ACE_Notification_Buffer *> alloc_queue_; + ACE_Unbounded_Queue <ACE_Notification_Buffer *> notify_queue_; + ACE_Unbounded_Queue <ACE_Notification_Buffer *> free_queue_; + + /// Synchronization for handling of queues. + ACE_SYNCH_MUTEX notify_queue_lock_; + + //@} +#endif /* ACE_HAS_REACTOR_NOTIFICATION_QUEUE */ + +}; + +// --------------------------------------------------------------------- + +/** + * @class ACE_Dev_Poll_Reactor_Handler_Repository + * + * @internal + + * @brief Used to map ACE_HANDLEs onto the appropriate + * ACE_Event_Handler *. + * + * + * This class is simply a container that maps a handle to its + * corresponding event handler. It is not meant for use outside of + * the Dev_Poll_Reactor. + */ +class ACE_Dev_Poll_Reactor_Handler_Repository +{ +public: + + /// Constructor. + ACE_Dev_Poll_Reactor_Handler_Repository (void); + + /// Initialize a repository of the appropriate <size>. + int open (size_t size); + + /// Close down the repository. + int close (void); + + /** + * @name Repository Manipulation Operations + * + * Methods used to search and modify the handler repository. + */ + //@{ + + /** + * Return the @c ACE_Event_Handler associated with @c ACE_HANDLE. If + * @a index_p is non-zero, then return the index location of the + * handle, if found. + */ + ACE_Event_Handler *find (ACE_HANDLE handle, size_t *index_p = 0); + + /// Set the event mask for event handler associated with the given + /// handle. + void mask (ACE_HANDLE handle, ACE_Reactor_Mask mask); + + /// Retrieve the event mask for the event handler associated with + /// the given handle. + ACE_Reactor_Mask mask (ACE_HANDLE handle); + + /// Mark the event handler associated with the given handle as + /// "suspended." + void suspend (ACE_HANDLE handle); + + /// Mark the event handler associated with the given handle as + /// "resumed." + void resume (ACE_HANDLE handle); + + /// Is the event handler for the given handle suspended? + int suspended (ACE_HANDLE handle) const; + + /// Bind the ACE_Event_Handler to the @c ACE_HANDLE with the + /// appropriate ACE_Reactor_Mask settings. + int bind (ACE_HANDLE handle, + ACE_Event_Handler *handler, + ACE_Reactor_Mask mask); + + /// Remove the binding for @c ACE_HANDLE; optionally decrement the associated + /// handler's reference count. + int unbind (ACE_HANDLE handle, bool decr_refcnt = true); + + /// Remove all the (@c ACE_HANDLE, @c ACE_Event_Handler) tuples. + int unbind_all (void); + + /** + * @name Sanity Checking + * + * Methods used to prevent "out-of-range" errors when indexing the + * underlying handler array. + */ + //@{ + + // Check the @a handle to make sure it's a valid @c ACE_HANDLE that + // within the range of legal handles (i.e., greater than or equal to + // zero and less than @c max_size_). + int invalid_handle (ACE_HANDLE handle) const; + + // Check the handle to make sure it's a valid @c ACE_HANDLE that is + // within the range of currently registered handles (i.e., greater + // than or equal to zero and less than @c max_handlep1_). + int handle_in_range (ACE_HANDLE handle) const; + + //@} + + /// Returns the current table size. + size_t size (void) const; + + /// Dump the state of an object. + void dump (void) const; + + /// Declare the dynamic allocation hooks. + ACE_ALLOC_HOOK_DECLARE; + +private: + + /// Maximum number of handles. + int max_size_; + + /// The underlying array of event handlers. + /** + * The array of event handlers is directly indexed directly using + * an @c ACE_HANDLE value. This is Unix-specific. + */ + ACE_Dev_Poll_Event_Tuple *handlers_; + +}; + +// --------------------------------------------------------------------- + +/** + * @class ACE_Dev_Poll_Reactor + * + * @brief A `/dev/poll' or `/dev/epoll' based Reactor implemenatation. + * + * @attention This reactor is @em experimental. + * + * The ACE_Dev_Poll_Reactor uses the `/dev/poll' or '/dev/epoll' + * character devices to demultiplex events on a given set of file + * descriptors. Unlike @c select(), `/dev/poll' and `/dev/epoll' have + * no hard-coded limit on the number of file descriptors that may be + * handled at any given time. As such, the ACE_Dev_Poll_Reactor can + * generally handle a much larger number of file descriptors than + * @c select() -based reactors. Furthermore, since `/dev/poll' and + * `/dev/epoll' both return a set of file descriptors that are active, + * there is no need to "walk" the set of file descriptors to determine + * which ones are active, such as what is done with the @c select() and + * @c poll() system calls. All returned file descriptors are active. + * This makes event dispatching very efficient. + * + * @note In general, this reactor may only be used to demultiplex + * events on sockets. Demultiplexing events on pipes, for + * example may not work. This is due to a limitation in the + * underlying `/dev/poll' device driver. + * + * @note It is only possible to achieve millisecond timeout + * resolutions with the @c ACE_Dev_Poll_Reactor. However, the + * timeout resolution for timers is independent of the reactors + * timeout resolution. As such, it may be possible to achieve + * sub-millisecond timeout resolutions for timers but that is + * entirely platform dependent. + */ + +#if defined (ACE_MT_SAFE) && (ACE_MT_SAFE != 0) +typedef ACE_Token ACE_DEV_POLL_TOKEN; +#else +typedef ACE_Noop_Token ACE_DEV_POLL_TOKEN; +#endif /* ACE_MT_SAFE && ACE_MT_SAFE != 0 */ +typedef ACE_Reactor_Token_T<ACE_DEV_POLL_TOKEN> ACE_Dev_Poll_Reactor_Token; + +class ACE_Export ACE_Dev_Poll_Reactor : public ACE_Reactor_Impl +{ +public: + + /// Initialize @c ACE_Dev_Poll_Reactor with the default size. + /** + * The default size for the @c ACE_Dev_Poll_Reactor is the maximum + * number of open file descriptors for the process. + */ + ACE_Dev_Poll_Reactor (ACE_Sig_Handler * = 0, + ACE_Timer_Queue * = 0, + int disable_notify_pipe = 0, + ACE_Reactor_Notify *notify = 0, + int mask_signals = 1, + int s_queue = ACE_DEV_POLL_TOKEN::FIFO); + + /// Initialize ACE_Dev_Poll_Reactor with size @a size. + /** + * @note On Unix platforms, the @a size parameter should be as large + * as the maximum number of file descriptors allowed for a + * given process. This is necessary since a file descriptor + * is used to directly index the array of event handlers + * maintained by the Reactor's handler repository. Direct + * indexing is used for efficiency reasons. If the size + * parameter is less than the process maximum, the process + * maximum will be decreased in order to prevent potential + * access violations. + */ + ACE_Dev_Poll_Reactor (size_t size, + int restart = 0, + ACE_Sig_Handler * = 0, + ACE_Timer_Queue * = 0, + int disable_notify_pipe = 0, + ACE_Reactor_Notify *notify = 0, + int mask_signals = 1, + int s_queue = ACE_DEV_POLL_TOKEN::FIFO); + + /// Close down and release all resources. + virtual ~ACE_Dev_Poll_Reactor (void); + + /// Initialization. + virtual int open (size_t size, + int restart = 0, + ACE_Sig_Handler * = 0, + ACE_Timer_Queue * = 0, + int disable_notify_pipe = 0, + ACE_Reactor_Notify * = 0); + + /** + * @param handle allows the reactor to check if the caller is + * valid. + * + * @return 0 if the size of the current message has been put in + * size. -1 if not. + */ + virtual int current_info (ACE_HANDLE handle, size_t & /* size */); + + /// Use a user specified signal handler instead. + virtual int set_sig_handler (ACE_Sig_Handler *signal_handler); + + /// Set a user-specified timer queue. + virtual int timer_queue (ACE_Timer_Queue *tq); + + /// Get the timer queue + /// @return The current @c ACE_Timer_Queue. + virtual ACE_Timer_Queue *timer_queue (void) const; + + /// Close down and release all resources. + virtual int close (void); + + // = Event loop drivers. + /** + * 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". + * + * @note It is only possible to achieve millisecond timeout + * resolutions with the @c ACE_Dev_Poll_Reactor. + */ + virtual int work_pending ( + const ACE_Time_Value &max_wait_time = ACE_Time_Value::zero); + + /** + * This event loop driver blocks for up to @a max_wait_time before + * returning. It will return earlier if events occur. Note that + * @a max_wait_time can be 0, in which case this method blocks + * indefinitely until events occur. + * @par + * @a 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 @c handle_events() and an event occurs after 2 seconds, + * @a max_wait_time will equal 1 second. This can be used if an + * application wishes to handle events for some fixed amount of + * time. + * @par + * The only difference between @c alertable_handle_events() and + * handle_events() is that in the alertable case, the event loop + * will return when the system queues an I/O completion routine or + * an Asynchronous Procedure Call. + * + * @return The total number of @c ACE_Event_Handlers that were + * dispatched, 0 if the @a max_wait_time elapsed without + * dispatching any handlers, or -1 if an error occurs. + + * @note It is only possible to achieve millisecond timeout + * resolutions with the @c ACE_Dev_Poll_Reactor. + */ + virtual int handle_events (ACE_Time_Value *max_wait_time = 0); + virtual int alertable_handle_events (ACE_Time_Value *max_wait_time = 0); + + /** + * This method is just like the one above, except the + * @a max_wait_time value is a reference and can therefore never be + * @c NULL. + * + * @note It is only possible to achieve millisecond timeout + * resolutions with the @c ACE_Dev_Poll_Reactor. + */ + virtual int handle_events (ACE_Time_Value &max_wait_time); + virtual int alertable_handle_events (ACE_Time_Value &max_wait_time); + + // = Event handling control. + + /** + * @return The status of Reactor. If this function returns 0, the + * reactor is actively handling events. If it returns + * non-zero, @c handle_events() and + * @c handle_alertable_events() return -1 immediately. + */ + virtual int deactivated (void); + + /** + * Control whether the Reactor will handle any more incoming events + * or not. If @a do_stop == 1, the Reactor will be disabled. By + * default, a reactor is in active state and can be + * deactivated/reactived as desired. + */ + virtual void deactivate (int do_stop); + + // = Register and remove Handlers. + + /// Register @a event_handler with @a mask. The I/O handle will + /// always come from get_handle on the event_handler. + virtual int register_handler (ACE_Event_Handler *event_handler, + ACE_Reactor_Mask mask); + + /// Register @a event_handler with @a mask. The I/O handle is + /// provided through the @a io_handle parameter. + virtual int register_handler (ACE_HANDLE io_handle, + ACE_Event_Handler *event_handler, + ACE_Reactor_Mask mask); + + /** + * Register an @a event_handler that will be notified when + * @a event_handle is signaled. @a mask specifies the network + * events that the @a event_handler is interested in. + */ + virtual int register_handler (ACE_HANDLE event_handle, + ACE_HANDLE io_handle, + ACE_Event_Handler *event_handler, + ACE_Reactor_Mask mask); + + /// Register @a event_handler> with all the @a handles> in the @c + /// Handle_Set. + virtual int register_handler (const ACE_Handle_Set &handles, + ACE_Event_Handler *event_handler, + ACE_Reactor_Mask mask); + + /** + * Register @a new_sh to handle the signal @a signum using the + * @a new_disp. Returns the @a old_sh that was previously + * registered (if any), along with the @a old_disp of the signal + * handler. + */ + 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); + + /// Registers <new_sh> to handle a set of signals <sigset> using the + /// <new_disp>. + virtual int register_handler (const ACE_Sig_Set &sigset, + ACE_Event_Handler *new_sh, + ACE_Sig_Action *new_disp = 0); + + /// Removes @a event_handler. + /** + * @note The I/O handle will be obtained using @c get_handle() + * method of @a event_handler . If @a mask == + * @c ACE_Event_Handler::DONT_CALL then the @c handle_close() + * method of the @a event_handler is not invoked. + */ + virtual int remove_handler (ACE_Event_Handler *event_handler, + 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 (ACE_HANDLE handle, + 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 (const ACE_Handle_Set &handle_set, + ACE_Reactor_Mask mask); + + /** + * 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 (int signum, + ACE_Sig_Action *new_disp, + ACE_Sig_Action *old_disp = 0, + int sigkey = -1); + + /// Calls <remove_handler> for every signal in <sigset>. + virtual int remove_handler (const ACE_Sig_Set &sigset); + + // = Suspend and resume Handlers. + + /// Suspend event_handler temporarily. Use + /// ACE_Event_Handler::get_handle() to get the handle. + virtual int suspend_handler (ACE_Event_Handler *event_handler); + + /// Suspend handle temporarily. + virtual int suspend_handler (ACE_HANDLE handle); + + /// Suspend all handles in handle set temporarily. + virtual int suspend_handler (const ACE_Handle_Set &handles); + + /// Suspend all handles temporarily. + virtual int suspend_handlers (void); + + /// Resume event_handler. Use ACE_Event_Handler::get_handle() to + /// get the handle. + virtual int resume_handler (ACE_Event_Handler *event_handler); + + /// Resume handle. + virtual int resume_handler (ACE_HANDLE handle); + + /// Resume all handles in handle set. + virtual int resume_handler (const ACE_Handle_Set &handles); + + /// Resume all handles. + virtual int resume_handlers (void); + + /// Does the reactor allow the application to resume the handle on + /// its own, i.e., can it pass on the control of handle resumption to + /// the application. + virtual int resumable_handler (void); + + /// Return 1 if we any event associations were made by the reactor + /// for the handles that it waits on, 0 otherwise. + virtual int uses_event_associations (void); + + // = Timer management. + + /** + * Schedule an ACE_Event_Handler that will expire after an amount + * of time. The return value of this method, a timer_id value, + * uniquely identifies the event_handler in the ACE_Reactor's + * internal list of timers. + * This timer_id value can be used to cancel the timer + * with the cancel_timer() call. + * + * @see cancel_timer() + * @see reset_timer_interval() + * + * @param event_handler event handler to schedule on reactor + * @param arg argument passed to the handle_timeout() method of + * event_handler. + * @param delay time interval after which the timer will expire. + * @param interval time interval for which the timer will be + * automatically rescheduled. + * @return -1 on failure, a timer_id value on success + */ + virtual long schedule_timer (ACE_Event_Handler *event_handler, + const void *arg, + const ACE_Time_Value &delay, + const ACE_Time_Value &interval = ACE_Time_Value::zero); + + /** + * 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 reset_timer_interval (long timer_id, + const ACE_Time_Value &interval); + + /// Cancel all Event_Handlers that match the address of + /// <event_handler>. Returns number of handlers cancelled. + virtual int cancel_timer (ACE_Event_Handler *event_handler, + int dont_call_handle_close = 1); + + /** + * Cancel the single event handler that matches the @a timer_id value + * (which was returned from the schedule method). If @a 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 @a timer_id + * wasn't found. + */ + virtual int cancel_timer (long timer_id, + const void **arg = 0, + int dont_call_handle_close = 1); + + // = High-level event handler scheduling operations + + /// Add <masks_to_be_added> to the <event_handler>'s entry. + /// <event_handler> must already have been registered. + virtual int schedule_wakeup (ACE_Event_Handler *event_handler, + 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 schedule_wakeup (ACE_HANDLE handle, + ACE_Reactor_Mask masks_to_be_added); + + /// Clear <masks_to_be_cleared> from the <event_handler>'s entry. + virtual int cancel_wakeup (ACE_Event_Handler *event_handler, + ACE_Reactor_Mask masks_to_be_cleared); + + /// Clear <masks_to_be_cleared> from the <handle>'s entry. + virtual int cancel_wakeup (ACE_HANDLE handle, + ACE_Reactor_Mask masks_to_be_cleared); + + // = Notification methods. + + /** + * 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 int notify (ACE_Event_Handler *event_handler = 0, + ACE_Reactor_Mask mask = ACE_Event_Handler::EXCEPT_MASK, + ACE_Time_Value * = 0); + + /** + * Set the maximum number of times that ACE_Reactor_Impl 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 void max_notify_iterations (int); + + /** + * Get the maximum number of times that the ACE_Reactor_Impl 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. + */ + virtual int max_notify_iterations (void); + + /** + * Purge any notifications pending in this reactor for the specified + * ACE_Event_Handler object. Returns the number of notifications + * purged. Returns -1 on error. + */ + virtual int purge_pending_notifications (ACE_Event_Handler * = 0, + ACE_Reactor_Mask = ACE_Event_Handler::ALL_EVENTS_MASK); + + /** + * Return the Event_Handler associated with <handle>. Return 0 if + * <handle> is not registered. + */ + virtual ACE_Event_Handler *find_handler (ACE_HANDLE handle); + + /** + * 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 (ACE_HANDLE handle, + ACE_Reactor_Mask mask, + 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 handler (int signum, + ACE_Event_Handler ** = 0); + + /// Returns true if Reactor has been successfully initialized, else + /// false. + virtual int initialized (void); + + /// Returns the current size of the Reactor's internal descriptor + /// table. + virtual size_t size (void) const; + + /// Returns a reference to the Reactor's internal lock. + virtual ACE_Lock &lock (void); + + /// Wake up all threads waiting in the event loop. + virtual void wakeup_all_threads (void); + + /// Transfers ownership of Reactor_Impl to the new_owner. + /** + * @note There is no need to set the owner of the event loop for the + * ACE_Dev_Poll_Reactor. Multiple threads may invoke the + * event loop simulataneously. As such, this method is a + * no-op. + */ + virtual int owner (ACE_thread_t new_owner, ACE_thread_t *old_owner = 0); + + /// Return the ID of the "owner" thread. + /** + * @note There is no need to set the owner of the event loop for the + * ACE_Dev_Poll_Reactor. Multiple threads may invoke the + * event loop simulataneously. As such, this method is a + * no-op. + */ + virtual int owner (ACE_thread_t *owner); + + /// Get the existing restart value. + virtual int restart (void); + + /// Set a new value for restart and return the original value. + /** + * @param r If zero, then the event loop will not be automatically + * restarted if the underlying poll is interrupted via the + * INTR (interrupt) signal. + * + * @return Returns the previous "restart" value. + */ + virtual int restart (int r); + + /// Set position of the owner thread. + /** + * @note This is currently a no-op. + */ + virtual void requeue_position (int); + + /// Get position of the owner thread. + /** + * @note This is currently a no-op. + */ + virtual int requeue_position (void); + + /** + * @name Low-level wait_set mask manipulation methods + * + * Low-level methods to manipulate the event/reactor mask associated + * with a handle and event handler when polling for events. + * @par + * The "interest set," i.e. the wait set, can be directly + * manipulated with these methods. + */ + //@{ + + /// GET/SET/ADD/CLR the dispatch mask "bit" bound with the + /// event_handler and mask. + /** + * @return Old mask on success, -1 on error. + */ + 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 handle + /// and mask. + /** + * @return Old mask on success, -1 on error. + */ + virtual int mask_ops (ACE_HANDLE handle, + ACE_Reactor_Mask mask, + int ops); + + //@} + + /** + * @name Low-level ready_set mask manipulation methods + * + * These methods are unimplemented. + */ + //@{ + + /// GET/SET/ADD/CLR the ready "bit" bound with the event_handler + /// and mask. + 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 handle and mask. + virtual int ready_ops (ACE_HANDLE handle, + ACE_Reactor_Mask, + int ops); + + //@} + + /// Dump the state of an object. + virtual void dump (void) const; + + /// Declare the dynamic allocation hooks. + ACE_ALLOC_HOOK_DECLARE; + +protected: + + class Token_Guard; + + /// Non-locking version of wait_pending(). + /** + * 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". + * + * @note It is only possible to achieve millisecond timeout + * resolutions with the ACE_Dev_Poll_Reactor. + */ + int work_pending_i (ACE_Time_Value *max_wait_time); + + /// Poll for events and return the number of event handlers that + /// were dispatched. + /** + * This is a helper method called by all handle_events() methods. + */ + int handle_events_i (ACE_Time_Value *max_wait_time, Token_Guard &guard); + + /// Perform the upcall with the given event handler method. + int upcall (ACE_Event_Handler *event_handler, + int (ACE_Event_Handler::*callback)(ACE_HANDLE), + ACE_HANDLE handle); + + /** + * Dispatch ACE_Event_Handlers for time events, I/O events, and + * signal events. Returns the total number of ACE_Event_Handlers + * that were dispatched or -1 if something goes wrong. + */ + int dispatch (Token_Guard &guard); + + /// Dispatch a single timer, if ready. + /// Returns: 0 if no timers ready (token still held), + /// 1 if a timer was expired (token released), + /// -1 on error (token still held). + int dispatch_timer_handler (Token_Guard &guard); + + /// Dispatch an IO event to the corresponding event handler. Returns + /// Returns: 0 if no events ready (token still held), + /// 1 if an event was expired (token released), + /// -1 on error (token still held). + int dispatch_io_event (Token_Guard &guard); + + /// Register the given event handler with the reactor. + int register_handler_i (ACE_HANDLE handle, + ACE_Event_Handler *eh, + ACE_Reactor_Mask mask); + + /// Remove the event handler associated with the given handle and + /// event mask from the "interest set." + int remove_handler_i (ACE_HANDLE handle, ACE_Reactor_Mask mask); + + /// Temporarily remove the given handle from the "interest set." + int suspend_handler_i (ACE_HANDLE handle); + + /// Place the given handle that was temporarily removed from the + /// "interest set," i.e that was suspended, back in to the interest + /// set. The given handle will once again be polled for events. + int resume_handler_i (ACE_HANDLE handle); + + /// GET/SET/ADD/CLR the dispatch MASK "bit" bound with the handle + /// and mask. This internal helper method acquires no lock. + /** + * @return Old mask on success, -1 on error. + */ + int mask_ops_i (ACE_HANDLE handle, + ACE_Reactor_Mask mask, + int ops); + + /// Convert a reactor mask to its corresponding poll() event mask. + short reactor_mask_to_poll_event (ACE_Reactor_Mask mask); + +protected: + + /// Has the reactor been initialized. + bool initialized_; + + /// The file descriptor associated with the open `/dev/poll' or + /// `/dev/epoll' device. + /** + * All interactions with the `/dev/poll' or `/dev/epoll' device are + * done through this file descriptor. + */ + ACE_HANDLE poll_fd_; + + /// The maximum number of file descriptors over which demultiplexing + /// will occur. + size_t size_; + + /// Track HANDLES we are interested in for various events that must + /// be dispatched *without* polling. + /// ACE_Dev_Poll_Ready_Set ready_set_; + +#if defined (ACE_HAS_EVENT_POLL) + /// Table of event structures to be filled by epoll_wait: + struct epoll_event *events_; + + /// Pointer to the next epoll_event array element that contains the next + /// event to be dispatched. + struct epoll_event *start_pevents_; + + /// The last element in the event array plus one. + /** + * The loop that dispatches IO events stops when this->start_pevents_ == + * this->end_pevents_. + */ + struct epoll_event *end_pevents_; + +#else + /// The pollfd array that `/dev/poll' will feed its results to. + struct pollfd *dp_fds_; + + + /// Pointer to the next pollfd array element that contains the next + /// event to be dispatched. + struct pollfd *start_pfds_; + + /// The last element in the pollfd array plus one. + /** + * The loop that dispatches IO events stops when this->start_pfds == + * this->end_pfds_. + */ + struct pollfd *end_pfds_; +#endif /* ACE_HAS_EVENT_POLL */ + + /// This flag is used to keep track of whether we are actively handling + /// events or not. + sig_atomic_t deactivated_; + + /// Lock used for synchronization of reactor state. + ACE_Dev_Poll_Reactor_Token token_; + + /// Adapter used to return internal lock to outside world. + ACE_Lock_Adapter<ACE_Dev_Poll_Reactor_Token> lock_adapter_; + + /// The repository that contains all registered event handlers. + ACE_Dev_Poll_Reactor_Handler_Repository handler_rep_; + + /// Defined as a pointer to allow overriding by derived classes... + ACE_Timer_Queue *timer_queue_; + + /// Keeps track of whether we should delete the timer queue (if we + /// didn't create it, then we don't delete it). + int delete_timer_queue_; + + /// Handle signals without requiring global/static variables. + ACE_Sig_Handler *signal_handler_; + + /// Keeps track of whether we should delete the signal handler (if we + /// didn't create it, then we don't delete it). + int delete_signal_handler_; + + /// Callback object that unblocks the <ACE_Select_Reactor> if it's + /// sleeping. + ACE_Reactor_Notify *notify_handler_; + + /// Keeps track of whether we need to delete the notify handler (if + /// we didn't create it, then we don't delete it). + int delete_notify_handler_; + + /// Flag that determines if signals are masked during event + /// dispatching. + /** + * If 0 then the Reactor will not mask the signals during the event + * dispatching. This is useful for applications that do not + * register any signal handlers and want to reduce the overhead + * introduce by the kernel level locks required to change the mask. + */ + int mask_signals_; + + /// Restart the handle_events event loop method automatically when + /// polling function in use (ioctl() in this case) is interrupted + /// via an EINTR signal. + int restart_; + +protected: + + /** + * @class Token_Guard + * + * @brief A helper class that helps grabbing, releasing and waiting + * on tokens for a thread that needs access to the reactor's token. + */ + class Token_Guard + { + public: + + /// Constructor that will grab the token for us + Token_Guard (ACE_Dev_Poll_Reactor_Token &token); + + /// Destructor. This will release the token if it hasn't been + /// released till this point + ~Token_Guard (void); + + /// Release the token .. + void release_token (void); + + /// Returns whether the thread that created this object owns the + /// token or not. + int is_owner (void); + + /// A helper method that acquires the token 1) at a low priority, and + /// 2) wait quietly for the token, not waking another thread. This + /// is appropriate for cases where a thread wants to wait for and + /// dispatch an event, not causing an existing waiter to relinquish the + /// token, and also queueing up behind other threads waiting to modify + /// event records. + int acquire_quietly (ACE_Time_Value *max_wait = 0); + + /// A helper method that acquires the token at a high priority, and + /// does wake the current token holder. + int acquire (ACE_Time_Value *max_wait = 0); + + private: + + Token_Guard (void); + + private: + + /// The Reactor token. + ACE_Dev_Poll_Reactor_Token &token_; + + /// Flag that indicate whether the thread that created this object + /// owns the token or not. A value of 0 indicates that this class + /// hasn't got the token (and hence the thread) and a value of 1 + /// vice-versa. + int owner_; + + }; + +}; + + +/** + * @class ACE_Dev_Poll_Handler_Guard + * + * @brief Class used to make event handler reference count + * manipulation exception-safe. + * + * This class makes the reference count manipulation that occurs + * during an upcall exception-safe. Prior to dispatching the event + * handler, the reference count is increased. Once the upcall for the + * given event handler is complete, its reference count will be decreased. + */ +class ACE_Dev_Poll_Handler_Guard +{ +public: + + /// Constructor + /** + * The constructor checks to see if @a eh is a reference-counted handler and + * remember that for later. If @a eh is reference counted, its reference + * count is incremented unless @a do_incr is false. + * @a do_incr should be false if the reference count was incremented + * independently of this guard, for example, on a notify handler since + * the reference count is incremented when the notify is queued. + */ + ACE_Dev_Poll_Handler_Guard (ACE_Event_Handler *eh, bool do_incr = true); + + /// Destructor + /** + * The destructor decrements the reference count on the event + * handler corresponding to the given handle. + */ + ~ACE_Dev_Poll_Handler_Guard (void); + + /// Release the event handler from this guard; when the destructor is + /// called, the handler's reference count will not be decremented. + void release (void); + +private: + + /// The event handler being managed. + ACE_Event_Handler *eh_; + + /// true if eh_ is a reference-counted handler. + bool refcounted_; + +}; + +ACE_END_VERSIONED_NAMESPACE_DECL + +#if defined (__ACE_INLINE__) +# include "ace/Dev_Poll_Reactor.inl" +#endif /* __ACE_INLINE__ */ + +#endif /* ACE_HAS_EVENT_POLL || ACE_HAS_DEV_POLL */ + +#include /**/ "ace/post.h" + +#endif /* ACE_DEV_POLL_REACTOR_H */ |