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/* -*- 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++
#include "mozilla/MemoryReporting.h"
/**
* 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++
virtual size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const = 0;
%}
};
%{C++
#define NS_TIMER_CONTRACTID "@mozilla.org/timer;1"
#define NS_TIMER_CALLBACK_TOPIC "timer-callback"
%}
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