The Timer Class

/*
**	(c) COPYRIGHT MIT 1995.
**	Please first read the full copyright statement in the file COPYRIGH.
*/

The Timer class handles timers for libwww and the application. This works exactly as in X where you create a timer object with a callback function and a timeout. The callback will be called every time the timer expires. There are several timeouts that can be set in libwww:

1. The time we keep an idle persistent connection open. Here there are in fact two mechanisms depending on whether you use blocking or non-blocking sockets. The default is 60 secs. The timers can be accessed using the functions defined in the HTHost object
2. The idle time we want to wait when receiving a response from a server, that is, if it doesn't send anything in a number of secs. The default here is no timeout. It can be accessed in the HTHost object as well.
3. The timeout before we flush pending requests in a pipeline, the default here is 30 ms. It is also accessed in the HTHost object
4. The timeout before we start sending the body of a PUT or POST request. Normally we send the Expect: 100-continue header field but if the server doesn't send back a 100 Continue code then we upload the body anyway. The default is 2 secs and can be accessed in the HTTP module.

#ifndef HTTIMER_H
#define HTTIMER_H

#include "wwwsys.h"
#include "HTReq.h"

#ifdef __cplusplus
extern "C" { 
#endif 

typedef struct _HTTimer HTTimer;

typedef int HTTimerCallback (HTTimer *, void *, HTEventType type);

Create and Delete Timers

The callback function is the function that is to be called when timer expires.

extern HTTimer * HTTimer_new (HTTimer *, HTTimerCallback *, 
			      void *, ms_t millis,
                              BOOL relative, BOOL repetitive);
extern BOOL HTTimer_delete (HTTimer * timer);
extern BOOL HTTimer_deleteAll (void);
extern BOOL HTTimer_expireAll (void);

Dispatch Timer

Just do it

extern int HTTimer_dispatch (HTTimer * timer);

Get the next timer in line

Dispatches all expired timers and optionally returns the time till the next one.

extern int HTTimer_next (ms_t * pSoonest);

Reset an already existing Repetitive Timer

extern BOOL HTTimer_refresh(HTTimer * timer, ms_t now);

Get Information about a Timer Object

Absolute Time when This Timer Expires

Absolute time in millies when this timer will expire

extern ms_t HTTimer_expiresAbsolute (HTTimer * timer);

Relative Time this Timer is running

Gived the relative time in millies that this timer was registered with. For example, a relative timer set to expire in 20ms will return 20.

#define HTTimer_getTime(t)	HTTimer_expiresRelative(t)
extern ms_t HTTimer_expiresRelative (HTTimer * timer);

Has this Timer Expired?

If so then it's time to call the dispatcher!

extern BOOL HTTimer_hasTimerExpired (HTTimer * timer);

What callback is this Timer Registered with?

extern HTTimerCallback * HTTimer_callback (HTTimer * timer);

Is this Time relative or Absolute?

extern BOOL HTTimer_isRelative (HTTimer * timer);

Platform Specific Timers

On some platform, timers are supported via events or other OS specific mechanisms. You can make libwww can support these by registering a platform specific timer add and timer delete method.

typedef BOOL HTTimerSetCallback (HTTimer * timer);

extern BOOL HTTimer_registerSetTimerCallback (HTTimerSetCallback * cbf);
extern BOOL HTTimer_registerDeleteTimerCallback (HTTimerSetCallback * cbf);

#ifdef __cplusplus
}
#endif

#endif /* HTTIMER_H */