The prot layer, defined in prot.h, is a stdio replacement for network i/o. It does the standard buffering of input and output and allows certain operations especially suited for request/response protocols like IMAP.
The prot layer allows "events" to be associated with each prot stream. These events are trigger at the given time or after when the protstream is attempted to be read from.
An event is currently represented by the following datastructure:
struct prot_waitevent;
typedef struct prot_waitevent *prot_waiteventcallback_t(struct protstream *s,
struct prot_waitevent *ev,
void *rock);
struct prot_waitevent {
time_t mark;
prot_waiteventcallback_t *proc;
void *rock;
struct prot_waitevent *next;
};
The application is currently allowed to modify mark, proc, and rock as desired when there are no active calls to a prot function on the stream which this event is associated.
The API is as followed:
extern struct prot_waitevent *prot_addwaitevent(struct protstream *s,
time_t mark,
prot_waiteventcallback_t *proc,
void *rock);
where s is the stream to add the event to, mark is
the time to trigger the event, proc is the callback to make,
and rock is an opaque data item handed to the callback. It
returns a pointer to the event structure; this is the pointer that
must be used to remove the event or modify it in some way.
extern void prot_removewaitevent(struct protstream *s,
struct prot_waitevent *event);
It requires event to have been returned from
prot_addwaitevent() previously. No further references are
allowed to event or its fields. event->rock is not
free'd nor examined in any way. This function may be called while
inside the callback event->proc(). If an event is removed
inside of its callback, that callback must return
NULL.Some common things to do with events: