ACE之ACE_Event_Handler

简介

ACE_Event_Handler是事件处理器，包含处理网络io，定时器以及信号，异常

结构

• 句柄相关：get_handle ，set_handle
• 优先级相关：priority，优先级的设置及获取
• 事件相关：handle_input ，handle_output ，handle_exception ，handle_timeout ，handle_exit(进程退出)，handle_close（当handle_*方法返回-1时或者reactor调用remove_handler）,handle_signal(处理信号)
• qos相关：handle_qos， handle_group_qos
• reactor相关：reactor的设置及获取

支持的事件类型有

• READ_MASK
• WRITE_MASK
• EXCEPT_MASK
• ACCEPT_MASK
• CONNECT_MASK
• TIMER_MASK
• QOS_MASK
• GROUP_QOS_MASK
• SIGNAL_MASK

信号事件

ACE_Sig_Handler用于管理事件，包含注册和删除信号相关的事件

ACE_Sig_Handler 其方法有

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);
virtual int remove_handler (int signum,ACE_Sig_Action *new_disp = 0,ACE_Sig_Action *old_disp = 0,int sigkey = -1);
static int sig_pending (void);
static void sig_pending (int);
virtual ACE_Event_Handler *handler (int signum);
virtual ACE_Event_Handler *handler (int signum, ACE_Event_Handler *);
static void dispatch (int, siginfo_t *,ucontext_t *);
void dump (void) const;

sig_pending_处理信号事件的标识
ACE_Sig_Set是对sigset_t的封装，其原方法有

int sigemptyset(sigset_t *set);
int sigfillset(sigset_t *set);
int sigaddset(sigset_t *sest, int signo);
int sigdelset(sigset_t *set, int signo);
int sigismember(const sigset_t *set, int signo);

封装后方法为

int empty_set (void);
int fill_set (void);
int sig_add (int signo);
int sig_del (int signo);
int is_member (int signo) const;
operator sigset_t *();
sigset_t sigset (void) const;
void dump (void) const;

ACE_Sig_Action是对sigaction的封装，其原方法为

int sigaction(int signo, const struct sigaction *restrict act, struct sigaction *restrict oact);

//sigaction定义
struct sigaction
{
	void (*sa_handler)(int);
	sigset_t sa_mask;
	int sa_flags;
	void (*sa_sigaction)(int, siginfo_t *, void*);
};

封装后方法有

int register_action (int signum,ACE_Sig_Action *oaction = 0);
int restore_action (int signum,ACE_Sig_Action &oaction);
int retrieve_action (int signum);
void set (struct sigaction *);
struct sigaction *get (void);
operator struct sigaction *();
void flags (int);
int flags (void);
void mask (sigset_t *);
void mask (ACE_Sig_Set &);
sigset_t *mask (void);
void handler (ACE_SignalHandler);
ACE_SignalHandler handler (void);
void dump (void) const;

handle_signal方法是在ACE_Sig_Handler::dispatch中被调用，会将sig_pending_ 置为1，reactor在handle_events时会根据此标识判断是否有处理事件，同时将sig_pending_复位

void
ACE_Sig_Handler::dispatch (int signum,
                           siginfo_t *siginfo,
                           ucontext_t *ucontext)
{
  ACE_Errno_Guard error (errno);
  ACE_Sig_Handler::sig_pending_ = 1;
  ACE_ASSERT (ACE_Sig_Handler::in_range (signum));
  ACE_Event_Handler *eh = ACE_Sig_Handler::signal_handlers_[signum];
  if (eh != 0)
    {
      if (eh->handle_signal (signum, siginfo, ucontext) == -1)
        ACE_Sig_Handler::remove_handler_i (signum);
#if defined (ACE_WIN32)
      else
        ACE_Sig_Handler::register_handler_i (signum, eh);
#endif /* ACE_WIN32*/
    }
}

信号处理函数是通过ACE_Sig_Handler::register_handler_i
分为两种情况，一种是c函数，一个是c++的
c函数使用

extern "C" void
ace_sig_handler_dispatch (int signum, siginfo_t *info, ucontext_t *context)
{
  ACE_TRACE ("ace_sig_handler_dispatch");
  ACE_Sig_Handler::dispatch (signum, info, context);
}

#define ace_signal_handler_dispatcher ACE_SignalHandler(ace_sig_handler_dispatch)

extern "C" void
ace_sig_handlers_dispatch (int signum, siginfo_t *info, ucontext_t *context)
{
  ACE_TRACE ("ace_sig_handlers_dispatch");
  ACE_Sig_Handlers::dispatch (signum, info, context);
}

#define ace_signal_handlers_dispatcher ACE_SignalHandler(ace_sig_handlers_dispatch)

c++使用

#define ace_signal_handler_dispatcher ACE_SignalHandler(ACE_Sig_Handler::dispatch)
#define ace_signal_handlers_dispatcher ACE_SignalHandler(ACE_Sig_Handlers::dispatch)