diff -r 000000000000 -r 6474c204b198 xpcom/threads/nsITimer.idl --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/xpcom/threads/nsITimer.idl Wed Dec 31 06:09:35 2014 +0100 @@ -0,0 +1,203 @@ +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- + * 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 http://mozilla.org/MPL/2.0/. */ + +#include "nsISupports.idl" + +interface nsIObserver; +interface nsIEventTarget; + +%{C++ +/** + * The signature of the timer callback function passed to initWithFuncCallback. + * This is the function that will get called when the timer expires if the + * timer is initialized via initWithFuncCallback. + * + * @param aTimer the timer which has expired + * @param aClosure opaque parameter passed to initWithFuncCallback + */ +class nsITimer; +typedef void (*nsTimerCallbackFunc) (nsITimer *aTimer, void *aClosure); +%} + +native nsTimerCallbackFunc(nsTimerCallbackFunc); + +/** + * The callback interface for timers. + */ +interface nsITimer; + +[function, scriptable, uuid(a796816d-7d47-4348-9ab8-c7aeb3216a7d)] +interface nsITimerCallback : nsISupports +{ + /** + * @param aTimer the timer which has expired + */ + void notify(in nsITimer timer); +}; + +%{C++ +// Two timer deadlines must differ by less than half the PRIntervalTime domain. +#define DELAY_INTERVAL_LIMIT PR_BIT(8 * sizeof(PRIntervalTime) - 1) +%} + +/** + * nsITimer instances must be initialized by calling one of the "init" methods + * documented below. You may also re-initialize (using one of the init() + * methods) an existing instance to avoid the overhead of destroying and + * creating a timer. It is not necessary to cancel the timer in that case. + * + * By default a timer will fire on the thread that created it. Set the .target + * attribute to fire on a different thread. Once you have set a timer's .target + * and called one of its init functions, any further interactions with the timer + * (calling cancel(), changing member fields, etc) should only be done by the + * target thread, or races may occur with bad results like timers firing after + * they've been canceled, and/or not firing after re-initiatization. + */ +[scriptable, uuid(193fc37a-8aa4-4d29-aa57-1acd87c26b66)] +interface nsITimer : nsISupports +{ + /* Timer types */ + + /** + * Type of a timer that fires once only. + */ + const short TYPE_ONE_SHOT = 0; + + /** + * After firing, a TYPE_REPEATING_SLACK timer is stopped and not restarted + * until its callback completes. Specified timer period will be at least + * the time between when processing for last firing the callback completes + * and when the next firing occurs. + * + * This is the preferable repeating type for most situations. + */ + const short TYPE_REPEATING_SLACK = 1; + + /** + * An TYPE_REPEATING_PRECISE repeating timer aims to have constant period + * between firings. The processing time for each timer callback should not + * influence the timer period. However, if the processing for the last + * timer firing could not be completed until just before the next firing + * occurs, then you could have two timer notification routines being + * executed in quick succession. Furthermore, if your callback processing + * time is longer than the timer period, then the timer will post more + * notifications while your callback is running. For example, if a + * REPEATING_PRECISE timer has a 10ms period and a callback takes 50ms, + * then by the time the callback is done there will be 5 events to run the + * timer callback in the event queue. Furthermore, the next scheduled time + * will always advance by exactly the delay every time the timer fires. + * This means that if the clock increments without the timer thread running + * (e.g. the computer is asleep) when the timer thread gets to run again it + * will post all the events that it "missed" while it wasn't running. Use + * this timer type with extreme caution. Chances are, this is not what you + * want. + */ + const short TYPE_REPEATING_PRECISE = 2; + + /** + * A TYPE_REPEATING_PRECISE_CAN_SKIP repeating timer aims to have constant + * period between firings. The processing time for each timer callback + * should not influence the timer period. However this timer type + * guarantees that it will not queue up new events to fire the callback + * until the previous callback event finishes firing. If the callback + * takes a long time, then the next callback will be scheduled immediately + * afterward, but only once, unlike TYPE_REPEATING_PRECISE. If you want a + * non-slack timer, you probably want this one. + */ + const short TYPE_REPEATING_PRECISE_CAN_SKIP = 3; + + /** + * Initialize a timer that will fire after the said delay. + * A user must keep a reference to this timer till it is + * is no longer needed or has been cancelled. + * + * @param aObserver the callback object that observes the + * ``timer-callback'' topic with the subject being + * the timer itself when the timer fires: + * + * observe(nsISupports aSubject, => nsITimer + * string aTopic, => ``timer-callback'' + * wstring data => null + * + * @param aDelay delay in milliseconds for timer to fire + * @param aType timer type per TYPE* consts defined above + */ + void init(in nsIObserver aObserver, in unsigned long aDelay, + in unsigned long aType); + + + /** + * Initialize a timer to fire after the given millisecond interval. + * This version takes a function to call and a closure to pass to + * that function. + * + * @param aFunc The function to invoke + * @param aClosure An opaque pointer to pass to that function + * @param aDelay The millisecond interval + * @param aType Timer type per TYPE* consts defined above + */ + [noscript] void initWithFuncCallback(in nsTimerCallbackFunc aCallback, + in voidPtr aClosure, + in unsigned long aDelay, + in unsigned long aType); + + /** + * Initialize a timer to fire after the given millisecond interval. + * This version takes a function to call. + * + * @param aFunc nsITimerCallback interface to call when timer expires + * @param aDelay The millisecond interval + * @param aType Timer type per TYPE* consts defined above + */ + void initWithCallback(in nsITimerCallback aCallback, + in unsigned long aDelay, + in unsigned long aType); + + /** + * Cancel the timer. This method works on all types, not just on repeating + * timers -- you might want to cancel a TYPE_ONE_SHOT timer, and even reuse + * it by re-initializing it (to avoid object destruction and creation costs + * by conserving one timer instance). + */ + void cancel(); + + /** + * The millisecond delay of the timeout. + * + * NOTE: Re-setting the delay on a one-shot timer that has already fired + * doesn't restart the timer. Call one of the init() methods to restart + * a one-shot timer. + */ + attribute unsigned long delay; + + /** + * The timer type - one of the above TYPE_* constants. + */ + attribute unsigned long type; + + /** + * The opaque pointer pass to initWithFuncCallback. + */ + [noscript] readonly attribute voidPtr closure; + + /** + * The nsITimerCallback object passed to initWithCallback. + */ + readonly attribute nsITimerCallback callback; + + /** + * The nsIEventTarget where the callback will be dispatched. Note that this + * target may only be set before the call to one of the init methods above. + * + * By default the target is the thread that created the timer. + */ + attribute nsIEventTarget target; +}; + +%{C++ +#define NS_TIMER_CONTRACTID "@mozilla.org/timer;1" +#define NS_TIMER_CALLBACK_TOPIC "timer-callback" +%} +