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Edit File: timer.h
/* * Copyright (C) Internet Systems Consortium, Inc. ("ISC") * * This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, you can obtain one at https://mozilla.org/MPL/2.0/. * * See the COPYRIGHT file distributed with this work for additional * information regarding copyright ownership. */ #ifndef ISC_TIMER_H #define ISC_TIMER_H 1 /***** ***** Module Info *****/ /*! \file isc/timer.h * \brief Provides timers which are event sources in the task system. * * Three types of timers are supported: * *\li 'ticker' timers generate a periodic tick event. * *\li 'once' timers generate an idle timeout event if they are idle for too * long, and generate a life timeout event if their lifetime expires. * They are used to implement both (possibly expiring) idle timers and * 'one-shot' timers. * *\li 'limited' timers generate a periodic tick event until they reach * their lifetime when they generate a life timeout event. * *\li 'inactive' timers generate no events. * * Timers can change type. It is typical to create a timer as * an 'inactive' timer and then change it into a 'ticker' or * 'once' timer. * *\li MP: * The module ensures appropriate synchronization of data structures it * creates and manipulates. * Clients of this module must not be holding a timer's task's lock when * making a call that affects that timer. Failure to follow this rule * can result in deadlock. * The caller must ensure that isc_timermgr_destroy() is called only * once for a given manager. * * \li Reliability: * No anticipated impact. * * \li Resources: * TBS * * \li Security: * No anticipated impact. * * \li Standards: * None. */ /*** *** Imports ***/ #include <stdbool.h> #include <isc/event.h> #include <isc/eventclass.h> #include <isc/lang.h> #include <isc/time.h> #include <isc/types.h> ISC_LANG_BEGINDECLS /*** *** Types ***/ /*% Timer Type */ typedef enum { isc_timertype_undefined = -1, /*%< Undefined */ isc_timertype_ticker = 0, /*%< Ticker */ isc_timertype_once = 1, /*%< Once */ isc_timertype_limited = 2, /*%< Limited */ isc_timertype_inactive = 3 /*%< Inactive */ } isc_timertype_t; typedef struct isc_timerevent { struct isc_event common; isc_time_t due; } isc_timerevent_t; #define ISC_TIMEREVENT_FIRSTEVENT (ISC_EVENTCLASS_TIMER + 0) #define ISC_TIMEREVENT_TICK (ISC_EVENTCLASS_TIMER + 1) #define ISC_TIMEREVENT_IDLE (ISC_EVENTCLASS_TIMER + 2) #define ISC_TIMEREVENT_LIFE (ISC_EVENTCLASS_TIMER + 3) #define ISC_TIMEREVENT_LASTEVENT (ISC_EVENTCLASS_TIMER + 65535) /*** *** Timer and Timer Manager Functions *** *** Note: all Ensures conditions apply only if the result is success for *** those functions which return an isc_result_t. ***/ isc_result_t isc_timer_create(isc_timermgr_t *manager, isc_timertype_t type, const isc_time_t *expires, const isc_interval_t *interval, isc_task_t *task, isc_taskaction_t action, void *arg, isc_timer_t **timerp); /*%< * Create a new 'type' timer managed by 'manager'. The timers parameters * are specified by 'expires' and 'interval'. Events will be posted to * 'task' and when dispatched 'action' will be called with 'arg' as the * arg value. The new timer is returned in 'timerp'. * * Notes: * *\li For ticker timers, the timer will generate a 'tick' event every * 'interval' seconds. The value of 'expires' is ignored. * *\li For once timers, 'expires' specifies the time when a life timeout * event should be generated. If 'expires' is 0 (the epoch), then no life * timeout will be generated. 'interval' specifies how long the timer * can be idle before it generates an idle timeout. If 0, then no * idle timeout will be generated. * *\li If 'expires' is NULL, the epoch will be used. * * If 'interval' is NULL, the zero interval will be used. * * Requires: * *\li 'manager' is a valid manager * *\li 'task' is a valid task * *\li 'action' is a valid action * *\li 'expires' points to a valid time, or is NULL. * *\li 'interval' points to a valid interval, or is NULL. * *\li type == isc_timertype_inactive || * ('expires' and 'interval' are not both 0) * *\li 'timerp' is a valid pointer, and *timerp == NULL * * Ensures: * *\li '*timerp' is attached to the newly created timer * *\li The timer is attached to the task * *\li An idle timeout will not be generated until at least Now + the * timer's interval if 'timer' is a once timer with a non-zero * interval. * * Returns: * *\li Success *\li No memory *\li Unexpected error */ isc_result_t isc_timer_reset(isc_timer_t *timer, isc_timertype_t type, const isc_time_t *expires, const isc_interval_t *interval, bool purge); /*%< * Change the timer's type, expires, and interval values to the given * values. If 'purge' is TRUE, any pending events from this timer * are purged from its task's event queue. * * Notes: * *\li If 'expires' is NULL, the epoch will be used. * *\li If 'interval' is NULL, the zero interval will be used. * * Requires: * *\li 'timer' is a valid timer * *\li The same requirements that isc_timer_create() imposes on 'type', * 'expires' and 'interval' apply. * * Ensures: * *\li An idle timeout will not be generated until at least Now + the * timer's interval if 'timer' is a once timer with a non-zero * interval. * * Returns: * *\li Success *\li No memory *\li Unexpected error */ isc_result_t isc_timer_touch(isc_timer_t *timer); /*%< * Set the last-touched time of 'timer' to the current time. * * Requires: * *\li 'timer' is a valid once timer. * * Ensures: * *\li An idle timeout will not be generated until at least Now + the * timer's interval if 'timer' is a once timer with a non-zero * interval. * * Returns: * *\li Success *\li Unexpected error */ void isc_timer_attach(isc_timer_t *timer, isc_timer_t **timerp); /*%< * Attach *timerp to timer. * * Requires: * *\li 'timer' is a valid timer. * *\li 'timerp' points to a NULL timer. * * Ensures: * *\li *timerp is attached to timer. */ void isc_timer_detach(isc_timer_t **timerp); /*%< * Detach *timerp from its timer. * * Requires: * *\li 'timerp' points to a valid timer. * * Ensures: * *\li *timerp is NULL. * *\li If '*timerp' is the last reference to the timer, * then: * *\code * The timer will be shutdown * * The timer will detach from its task * * All resources used by the timer have been freed * * Any events already posted by the timer will be purged. * Therefore, if isc_timer_detach() is called in the context * of the timer's task, it is guaranteed that no more * timer event callbacks will run after the call. *\endcode */ isc_timertype_t isc_timer_gettype(isc_timer_t *timer); /*%< * Return the timer type. * * Requires: * *\li 'timer' to be a valid timer. */ isc_result_t isc_timermgr_create(isc_mem_t *mctx, isc_timermgr_t **managerp); /*%< * Create a timer manager. * * Notes: * *\li All memory will be allocated in memory context 'mctx'. * * Requires: * *\li 'mctx' is a valid memory context. * *\li 'managerp' points to a NULL isc_timermgr_t. * * Ensures: * *\li '*managerp' is a valid isc_timermgr_t. * * Returns: * *\li Success *\li No memory *\li Unexpected error */ void isc_timermgr_destroy(isc_timermgr_t **managerp); /*%< * Destroy a timer manager. * * Notes: * *\li This routine blocks until there are no timers left in the manager, * so if the caller holds any timer references using the manager, it * must detach them before calling isc_timermgr_destroy() or it will * block forever. * * Requires: * *\li '*managerp' is a valid isc_timermgr_t. * * Ensures: * *\li *managerp == NULL * *\li All resources used by the manager have been freed. */ void isc_timermgr_poke(isc_timermgr_t *m); ISC_LANG_ENDDECLS #endif /* ISC_TIMER_H */